WO2015185660A1

WO2015185660A1 - Trifluoroborate-substituted lithium pyrazoles and use thereof as conducting salt for lithium-based energy storage

Info

Publication number: WO2015185660A1
Application number: PCT/EP2015/062444
Authority: WO
Inventors: Martin Manuel Hiller; Mariano GRÜNEBAUM; Hans-Dieter WIEMHÖFER
Original assignee: Westfälische Wilhelms-Universität Münster
Priority date: 2014-06-06
Filing date: 2015-06-03
Publication date: 2015-12-10
Also published as: DE102014108012B4; DE102014108012A1

Abstract

The invention relates to trifluoroborate-substituted lithium-pyrazolides, use thereof as conducting salt in lithium-based electrochemical energy storage devices and electrolytes containing trifluoroborate-substituted lithium-pyrazolides.

Description

TRIFLUORBORATE-SUBSTITUTED LITHIUM PYRAZOLE AND THEIR USE AS A LEAD SALT FOR LITHIUM-BASED ENERGY STORAGE

The invention relates to conductive salts and these containing electrolytes for lithium-based energy storage.

In recent years, lithium-ion batteries have become compared to others

Battery concepts proved to be the most efficient and powerful battery concept on the market. In this case, lithium salts are used as conductive salt in combination with lithium ion-conducting polymers or dissolved in organic solvents in combination with

Separator materials used, which then find use as electrolytes in lithium polymer batteries. In commercially available lithium-ion batteries, lithium hexafluorophosphate (LiPF ₆ ) is mostly used as conductive salt. Since its introduction, in addition to a rare use of lithium tetrafluoroborate (LiBF ₄ ) or lithium perchlorate (LiC10 ₄ ), largely due to the high electrochemical stability and good conductivity of LiPF _ö only this made its way into the battery market. However, LiPF ₆ forms under the influence of traces of moisture hydrogen fluoride (HF) and phosphoryl fluoride POF ₃ , which destroys the lithium-ion batteries from the inside. In addition, LiPF _ö -based battery systems can not be operated at temperatures above 70 ° C, since LiPF ₆ decomposes from this temperature. Despite intensive efforts to develop lithium salts that can replace LiPF ₆ as conductive salt, no alternative lithium salts have yet been established for commercial use for various reasons. Lithium salts of sulfonylimides such as LiN (S0 ₂ CF ₃ ) ₂ (LiTFSI) and LiN (S0 ₂ C ₂ F ₅ ) ₂ (LiBETI) as well as methides have a corrosive and non-passivating effect on aluminum current collectors. In addition, like most lithium salts, they are too expensive for commercial use.

Borates, for example, the lithium bis (oxalato) borate (LiBOB) disclosed in DE 198 29 030 C1, and oxo-phosphates usually have too low an ionic conductivity. This is due to too large molecular anions, which greatly increase the viscosity of liquid electrolytes and have a low degree of dissociation of anion and cation.

In addition, the conductivity is lowered by the formation of poorly ion-conducting electrode solid electrolyte interphase boundaries (SEI).

Despite a large number of proposed salts, no suitable substitute for LiPF _{6 has} yet been found as conducting salt in the carbonate mixtures usually used as solvents. Therefore, there is a need for alternative lithium salts for use in lithium ion batteries.

The present invention was therefore based on the object, a connection to

To provide, which overcomes at least one of the aforementioned disadvantages of the prior art. In particular, the object of the present invention was to provide a lithium compound suitable as a conductive salt.

This object is achieved by a trifluoroborate-substituted lithium pyrazolide according to the general formula (1) as indicated below

wherein:

R R is the same or independently selected from the

Group comprising linear or branched alkyl or cycloalkyl groups having 1 to 12 carbon atoms, linear or branched perfluorinated or partially fluorinated alkyl or cycloalkyl groups having 1 to 12 carbon atoms and / or perfluorinated or partially fluorinated phenyl. Surprisingly, it has been found that trifluoroborate-substituted lithium pyrazolides according to the general formula (1) in commercially used battery solvents such as

Mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) in the ratio 1: 1 in a wide temperature range have a high ionic conductivity. Thus, it was found that the lithium salts have a high ionic conductivities in a broad range

Temperature windows, for example, 1-1 (T -2 S / cm at 90 ° C, 5.4 · 10 - ^" 3 ^J S / cm at 25 ° C and 2 x 10 ^{" 3} S / cm at -20 ° C. ,

Another advantage is that the trifluoroborate-substituted pyrazolides a high

have electrochemical stability. Thus, the trifluoroborate-substituted pyrazolides show stability above 5 V in the anodic region. Li / Li ⁺ and are stable to standard hydrogen in the cathodic range up to lithium metal deposition / dissolution at -3.02V. Furthermore, the salts show passivating properties against aluminum current collectors. High cycle stability over long periods of time is also advantageous

Battery solvents in half and full cells with commercially used

Electrode materials such as lithium iron phosphate (LFP), graphite, lithium titanate (LTO) and lithium-nickel-cobalt-manganese oxide (NCM). Even at high unloading and loading rates, a high capacity was achieved. In addition, the trifluoroborate-substituted lithium pyrazolides are easily accessible chemically and can be prepared from favorable starting materials. Of particular advantage is the high ionic conductivity of the trifluoroborate-substituted lithium pyrazolides. Without being bound to any particular theory, it is believed that this is effected by the BF ₃ modification of the nitrogen atoms. A high Ionic conductivity was especially observed at low temperatures.

In preferred embodiments, the substituents R Fl and R F2 are each the same or independently selected from the group comprising linear or branched perfluorinated alkyl or cycloalkyl groups having 1 to 12, preferably 1 to 6, carbon atoms and / or pentafluorophenyl. Advantageously, trifluoroborate-substituted

Pyrazolides with perfluorinated groups R Fl and R F2 are not susceptible to hydrolysis. Preferably, R Fl and R F2 are each the same or independently of one another a linear perfluorinated alkyl group having 1 to 12, preferably 1 to 6, carbon atoms. Particularly preferably, R Fl and R F _{2 are} each the same or independently selected from the group comprising CF ₃ , C ₂ F ₅ , C ₃ F ₇ and / or C ₄ F ₉ . Trifluoroborate-substituted pyrazolides with smaller perfluorinated groups R Fl and R F2 show good conductivity and performance in an electrochemical cell.

R Fl and R F2 may be the same or different. For example, R Fl

CF ₃ and R F _{2 is} CF ₃ , C ₂ F ₅ , C ₃ F ₇ or C ₄ F ₉ . Alternatively, R ^F2 may be CF ₃ and R ^{F1 is} CF ₃ , C ₂ F ₅ , C ₃ F ₇ or C ₄ F ₉ .

Alternatively, R Fl and R F2 may both be C ₂ F ₅ . In preferred embodiments, the trifluoroborate-substituted lithium pyrazolide is selected from the group comprising:

Lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate,

Lithium [5 - (perfluoroethyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate,

- Lithium [5- (perfluoropropyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate and / or

- Lithium [5- (perfluorobutyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate. In further preferred embodiments, one of the substituents R F1 and R F2 is a linear or branched alkyl or cycloalkyl group having 1 to 12, preferably 1 to 6, carbon atoms.

Atoms and one of the substituents R Fl and R F2 is a linear or branched perfluorinated or partially fluorinated alkyl or cycloalkyl group having 1 to 12, preferably 1 to 6, Carbon atoms. R or R may be selected from the group comprising CH ₃ , C ₃ H ₇ and / or R may be R Fl

C ₂ H ₅ , C ₄ H ₉ . For example, be selected from the group comprising CH ₃ , F2

C ₂ H ₅ , C ₃ H ₇ and / or C ₄ H ₉ and R are selected from the group comprising CF ₃ , C ₂ F ₅ , C ₃ F ₇ and / or C ₄ F ₉ . A preferred trifluoroborate-substituted lithium pyrazolide having a non-fluorinated group R Fl or R F2 is lithium (3-methyl-5- (trifluoromethyl) pyrazolyl) trifluoroborate.

In further preferred embodiments, one of the substituents R Fl and R F2 is a linear or branched perfluorinated or partially fluorinated alkyl or cycloalkyl group having 1 to 12, preferably 1 to 6, carbon atoms and one of the substituents R Fl and R F2 perfluorinated or partially fluorinated phenyl. In particular, R F2 may be perfluorinated or partially fluorinated phenyl. A preferred trifluoroborate-substituted lithium pyrazolide having a perfluorinated or partially fluorinated phenyl group R Fl or R F 2 is lithium (3- (perfluorophenyl) -5- (trifluoromethyl) pyrazolyl) trifluoroborate.

By combining the properties of a high ionic conductivity in a wide temperature range, high solubility and dissociation in organic

Solvents, a high electrochemical stability of up to 5 V vs. Li / Li ⁺ , a high cycle stability over long periods of time, even at high loading and unloading rates against commercial electrode materials, high temperature stability, passivating properties against aluminum current collectors, and insensitivity to moisture, the trifluoroborate-substituted lithium pyrazolides are advantageous as conductive salt in lithium -based electrochemical cells and energy storage devices. Another object of the invention therefore relates to the use of a trifluoroborate-substituted lithium pyrazolide according to the general formula (1) as indicated below BF,

N-N

R F1 F2 Li

(1)

Wonn:

R Fl R F2 is in each case the same or independently selected from the group comprising linear or branched alkyl or cycloalkyl groups having 1 to 12 carbon atoms, linear or branched perfluorinated or partially fluorinated alkyl or cycloalkyl groups having 1 to 12 carbon Atoms and / or perfluorinated or partially fluorinated phenyl,

as conducting salt in lithium-based electrochemical cells and

Energy storage devices.

In preferred embodiments, trifluoroborate-substituted lithium pyrazolides are useful whose substituents R Fl and R F2 are each equal to or independently selected from the group comprising linear or branched perfluorinated alkyl or cycloalkyl groups having 1 to 12, preferably 1 to 6, Carbon atoms and / or

Pentafluorophenyl. Advantageously, in contrast to the commercial lithium salts LiPF ₆ and LiBF ₄ , trifluoroborate-substituted pyrazolides with perfluorinated groups R.sub.F and R.sub.F2 are not susceptible to hydrolysis and formation of HF is not present in solvents. Such decomposition was substituted on the perfluorinated trifluoroborate

Lithium salts not observed. Preferably, R Fl and R F2 are each the same or independently of each other, a linear perfluorinated alkyl group having 1 to 12, preferably 1 to

6, carbon atoms. Particularly preferably, R Fl and R F2 are each the same or independently selected from the group comprising CF ₃ , C ₂ F ₅ , C ₃ F ₇ and / or substituted pyrazolides having smaller perfluorinated groups R Fl and R F2

C ₄ F ₉ . Trifluoroborate-s

show, in suitable amounts dissolved in a solvent, a lower viscosity than the longer homologs and are useful with particularly good conductivity and performance in a cell. R and R may be the same or different. For example, R can be CF ₃ and R CF ₃ , C ₂ F ₅ , C ₃ F ₇ or C ₄ F ₉ . Alternatively, R ^F2 may be CF ₃ and R ^{F1 is} CF ₃ , C ₂ F ₅ , C ₃ F ₇ or C ₄ F ₉ .

Alternatively, R Fl and R F2 may both be C ₂ F ₅ . Particularly preferably usable is a trifluoroborate-substituted lithium pyrazolide selected from the group comprising:

Lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate,

- Lithium [5- (perfluorobutyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate.

In particular, these trifluoroborate-substituted lithium pyrazolides show a favorable combination of the properties of a high ionic conductivity in a wide

Temperature range, high solubility in salt and dissociation in organic solvents, an electrochemical stability above 5 V, passivating properties against aluminum current collectors, high temperature and cycle stability and insensitivity to moisture. Lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate, lithium [5- (perfluoroethyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate, lithium [5- (5) perfluoropropyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate and lithium [5- (perfluorobutyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate are particularly advantageous as conductive salt in lithium based electrochemical cells and energy storage devices usable.

In further preferred embodiments, one of the substituents R F1 and R F2 is a linear or branched alkyl or cycloalkyl group having 1 to 12, preferably 1 to 6, carbon atoms.

Atoms and one of the substituents R Fl and R F2 is a linear or branched perfluorinated or partially fluorinated alkyl or cycloalkyl group having 1 to 12, preferably 1 to 6,

Carbon atoms. R Fl or R F2 may be selected from the group comprising CH ₃ , d / or C ₄ H ₉ . For example, R Fl

C ₂ H ₅ , C ₃ H ₇ un be selected from the group

F2

comprising CH ₃ , C ₂ H ₅ , C ₃ H ₇ and / or C ₄ Hg and R selected from the group comprising CF ₃ , C ₂ F ₅ , C ₃ F ₇ uno / or C ₄ F ₉ . A preferred trifluoroborate-substituted lithium

Pyrazolide with a non-fluorinated group R F1 or R F2 is lithium (3-methyl-5- (trifluoromethyl) pyrazolyl) trifluoroborate. In further preferred embodiments, one of the substituents R Fl and R F2 is a linear or branched perfluorinated or partially fluorinated alkyl or cycloalkyl group having 1 to 12, preferably 1 to 6, carbon atoms and one of the substituents R Fl and R F2 perfluorinated or partially fluorinated phenyl. In particular, R F2 may be perfluorinated or partially fluorinated phenyl. A preferred trifluoroborate-substituted lithium pyrazolide having a perfluorinated or partially fluorinated phenyl group R Fl or R F 2 is lithium (3- (perfluorophenyl) -5- (trifluoromethyl) pyrazolyl) trifluoroborate.

Another object of the invention relates to an electrolyte for a lithium-based electrochemical cell or energy storage device comprising a trifluoroborate-substituted lithium pyrazolide according to the general formula (1) as indicated below

wherein:

Each F2 is the same or independently selected from the group comprising linear or branched alkyl or cycloalkyl groups having 1 to 12 carbon atoms, linear or branched perfluorinated or partially fluorinated alkyl or cycloalkyl groups having 1 to 12 carbon atoms and / or perfluorinated or partially fluorinated phenyl.

Electrolytes comprising trifluoroborate-substituted lithium pyrazolides according to the general formula (1) have a high electrochemical stability and allow highly efficient Lithium-based energy storage systems with partially better performance than comparable commercial LiPF _ö -based systems. Electrolytes comprising trifluoroborate-substituted lithium pyrazolides as conductive salt are characterized by their thermal and

electrochemical stability excellent in electrochemical cells and

Energy storage devices usable.

Furthermore, electrolytes comprising trifluoroborate-substituted lithium pyrazolides show no corrosion of the aluminum used as a current collector, but like LiPF ₆ passivating properties against aluminum current collectors. In particular, electrolytes comprising trifluoroborate-substituted lithium pyrazolides even at high loading and

Discharge rates high cycle stability over long periods against commercial

Electrode materials.

In preferred embodiments, the substituents R F1 and R F2 are each the same or independently selected from the group comprising linear or branched perfluorinated alkyl or cycloalkyl groups having 1 to 12, preferably 1 to 6, carbon atoms.

Atoms and / or pentafluorophenyl. Preferably, R Fl and R F2 are each the same or independently of each other, a linear perfluorinated alkyl group having 1 to 12, preferably 1 to

6, carbon atoms. Particularly preferably, R Fl and R F2 are each the same or independently selected from the group comprising CF ₃ , C ₂ F ₅ , C ₃ F ₇ and / or orborate-substituted pyrazolides having smaller perfluorinated groups R Fl and R F2

C ₄ F ₉ . trifluoroacetic

show good conductivity and performance in an electrochemical cell.

R Fl and R F2 may be the same or different. For example, R Fl can be CF ₃ and R F _{2 is} CF ₃ , C ₂ F ₅ , C ₃ F ₇ or C ₄ F ₉ . Alternatively, R ^F2 may be CF ₃ and R ^{F1 is} CF ₃ , C ₂ F ₅ , C ₃ F ₇ or C ₄ F ₉ .

Alternatively, R Fl and R F2 may both be C ₂ F ₅ . Preferably, the trifluoroborate-substituted lithium pyrazolide is selected from the group comprising:

Lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate, Lithium [5- (perfluoroethyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate,

- Lithium [5- (perfluorobutyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate. These trifluoroborate-substituted lithium pyrazolides show a particularly advantageous combination of the properties of a high ionic conductivity in a wide

Temperature range, high solubility in salt and dissociation in organic solvents, an electrochemical stability above 5 V, passivating properties against aluminum current collectors, high temperature and cycle stability and insensitivity to moisture.

Carbon atoms. R Fl or R F2 can be selected from the group comprising CH ₃ , as can R Fl

C ₂ H ₅ , C ₃ H ₇ and / or C ₄ H ₉ . For example, be selected from the group comprising CH ₃ , C ₃ H ₇ and / or F2

C ₂ H ₅ , C ₄ H ₉ and R selected from the group comprising CF ₃ , C ₂ F ₅ , C ₃ F ₇ and / or C ₄ F ₉ . A preferred trifluoroborate-substituted lithium pyrazolide having a non-fluorinated group R Fl or R F2 is lithium (3-methyl-5- (trifluoromethyl) pyrazolyl) trifluoroborate.

In further preferred embodiments, one of the substituents R Fl and R F2 is a linear or branched perfluorinated or partially fluorinated alkyl or cycloalkyl group having 1 to 12, preferably 1 to 6, carbon atoms and one of the substituents R Fl and R F2 perfluorinated or partially fluorinated phenyl. In particular, R F2 may be perfluorinated or partially fluorinated phenyl. A preferred trifluoroborate-substituted lithium pyrazolide with a perfluorinated or partially fluorinated phenyl group R or R is lithium (3- (perfluorophenyl) -5- (trifluoromethyl) pyrazolyl) trifluoroborate.

Trifluoroborate-substituted lithium pyrazolides can be used as conducting salt in combination with lithium ion-conducting polymers, polymer gels or dissolved in solvents

Combination with separator materials can be used. These electrolytes can be used advantageously as safe and easy to handle electrolytes in lithium-ion or polymer batteries use. The electrolyte in lithium-based

storing electrochemical energy ensures charge transport. The conductive salt is therefore preferably dissolved as a liquid electrolyte in a solvent.

The electrolyte may contain conventional non-aqueous solvents used in electrolytes, for example cyclic or linear carbonates, nitriles or lactones.

Solvents are in particular selected from the group comprising propylene carbonate, ethylene carbonate (EC), diethyl carbonate, dimethyl carbonate (DMC), ethylmethyl carbonate, acetonitrile, glutaronitrile, adiponitrile, pimelonitrile, gamma-butyrolactone, gamma-valerolactone and / or mixtures thereof. Preferred solvents are selected from mixtures of ethylene carbonate and dimethyl carbonate or diethyl carbonate

Propylene carbonate and / or gamma-butyrolactone.

In preferred embodiments, the concentration of trifluoroborate-substituted lithium pyrazolide in the electrolyte is in the range of> 0.5 mol / kg to <1.25 mol / kg, preferably in the range of> 0.75 mol / kg to <1 mol / kg, more preferably in the range of> 0.75 mol / kg to <0.85 mol / kg. For example, the concentration may be 0.75 mol / kg, 0.8 mol / kg or 1 mol / kg. It was found that the ionic conductivities of the perfluorinated trifluoroborate-substituted lithium pyrazolides at a concentration of 0.75 mol / kg of solvent at 1-10 ^"2 S / cm at 90 ° C, 5.4 · 10 ^{" 3} S / cm at 25 ° C and 2 · 10 ^" S / cm at -20 ° C and thus comparable to the very high conductivity of the commercial system 1 mol / kg LiPF ₆ in EC / DMC 1: 1. At lower temperatures, lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate in EC / DMC showed 1: 1 higher conductivity than the commercial LiPF ₆ in ethylene carbonate / diethyl carbonate (3: 7 weight ratio). , Similarly high conductivities also showed 0.8 mol / kg of lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate in propylene carbonate of 4 · 1 (Γ S / cm at 25 ° C.

The electrolyte may further comprise additives, in particular compounds which are suitable for forming a so-called solid electrolyte interphase (SEI), a solid-electrolyte interface, in a targeted manner. These can be the specific capacity and thus the

Improve overall properties of the electrolyte.

Another object of the invention relates to a lithium-based electrochemical cell or energy storage device comprising an electrolyte according to the invention. The term "electrochemical energy storage device" includes batteries (primary storage) and accumulators (secondary storage) .These are usually constructed from one or more electrochemical cells However, in common usage, accumulators are often also referred to as the term battery commonly used as a generic term. Unless otherwise indicated In the present case, the term lithium-ion battery is also used synonymously with lithium-ion accumulator. <br /><br/> Preferred lithium-based electrochemical energy storage devices are selected from the group consisting of lithium battery, lithium ion battery, lithium ion accumulator, lithium ion battery. Polymer battery, lithium-ion capacitor and / or dual-ion cell The trifluoroborate-substituted lithium pyrazolides according to the general formula (1) can be prepared by customary methods, preference being given to a process for preparing a trifluoroborate-substituted lithium Pyraz olides, wherein a pyrazole according to the general formula (2) as indicated below:

wherein:

R Fl R F2 is in each case the same or independently selected from the group comprising linear or branched alkyl or cycloalkyl groups having 1 to 12 carbon atoms, linear or branched perfluorinated or partially fluorinated

Alkyl or cycloalkyl groups having 1 to 12 carbon atoms and / or perfluorinated or partially fluorinated phenyl,

lithiated and then reacted with BF ₃ . It is particularly advantageous in the process according to the invention that the lithiation and reaction with BF _{3 take place} without separation of a lithiated intermediate in one step. The trifluoroborate-substituted lithium pyrazolides are thereby chemically readily accessible. By means of the process according to the invention, the trifluoroborate-substituted lithium pyrazolides can be prepared from inexpensive and commercially readily available educts by means of a short and reliable synthesis without expensive purification steps.

Preferably, R Fl and R F2 are each the same or independently selected from the group comprising linear or branched perfluorinated alkyl or cycloalkyl groups having 1 to 12, preferably 1 to 6, carbon atoms and / or pentafluorophenyl. Preferably, R Fl and R F 2 are each the same or independently of each other a linear perfluorinated alkyl

Group of 1 to 12, preferably 1 to 6, carbon atoms. Particularly preferably, R Fl and R F2 are each the same or independently selected from the group comprising

CF ₃ , F ₇ and / or Fl F2

C ₂ F ₅ , C ₃ C ₄ F ₉ . R and R may be the same or different.

For example, RF 1 can be CF ₃ and RF "2 CF ₃ , C ₂ F ₅ , C ₃ F ₇ or C ₄ F ₉ Alternatively, RF" 2 CF ₃ and R Fl CF ₃ , ₃ F ₇ or C ₄ F ₉ . Alternatively, R Fl and R F2

C ₂ F ₅ , C be both C ₂ F ₅ . In further preferred embodiments, one of the substituents R and R is a linear or branched alkyl or cycloalkyl group having 1 to 12, preferably 1 to 6, carbon atoms.

Atoms and one of the substituents R Fl and R F2 is a linear or branched perfluorinated or partially fluorinated alkyl or cycloalkyl group having 1 to 12, preferably 1 to 6, carbon atoms. R Fl or R F2 can be selected from the group comprising CH ₃ ,

Fl

C ₂ H ₅ , C ₃ H ₇ and / or C ₄ H ₉ . For example, R can be selected from the group comprising CH ₃ , F ₂

C ₂ H ₅ , C ₃ H ₇ and / or C ₄ H ₉ and R are selected from the group comprising CF ₃ , C ₂ F ₅ , C ₃ F ₇ and / or C ₄ F ₉ . In further preferred embodiments, one of the

Substituents R Fl and R F2 is a linear or branched perfluorinated or partially fluorinated alkyl or cycloalkyl group having 1 to 12, preferably 1 to 6, carbon atoms and one of the substituents R Fl and R F2 perfluorinated or partially fluorinated phenyl.

In particular, R F2 may be perfluorinated or partially fluorinated phenyl.

The starting material, the pyrazole according to the general formula (2) is conventional

Methods, preferably by reacting a diketone R ^F1 CH ₂ -C (O) -CH ₂ -C (O) -CH ₂ R ^F2 with hydrazine hydrate with the addition of phosphorus pentoxide, produced. The reaction of the diketone with hydrazine hydrate can be carried out in the presence of equivalent amounts of phosphorus pentoxide, preferably with heating, in particular under reflux in chloroform. The lithiation of the pyrazole according to the general formula (2) is preferably carried out using metal salts or organometallic compounds such as n-butyllithium or

Lithium amide. Suitable are organic solvents such as w-hexane. According to the invention, BF _{3 is} added directly to the reaction solution without subsequent removal of a lithiated intermediate. Preferably, BF ₃ is useful as an etherate. It may alternatively be used as BF ₃ gas or in combination with an inert carrier gas such as nitrogen or argon, or in the form of the condensed gas. Suitable BF ₃ ethers are ethereal complex compounds or complex solutions with ethers having alkyl-based substituents with the same or different chain length, such as dimethyl ether, diethyl ether, dipropyl ether, tetrahydrofuran or tetrahydropyran. Also suitable are alcoholic complex compounds or complex solutions with alcohols having alkyl-based substituents with the same or different chain lengths, such as methanol, ethanol, propanol, isopropanol or butanol. Also suitable are Aminic

Complex compounds or complex solutions with tertiary amines having alkyl-based substituents of the same or different chain length, such as trimethylamine,

Triethylamine, tripropylamine or diethylethylamine.

Preference is given to ethers, in particular diethyl ether-boron trifluoride. The reaction of the lithiated pyrazole can be treated with etherate in an amount of equivalents in the range of> 0.2 equiv. to <2 equiv., preferably in the range of> 0.5 equiv. to <1.5 equiv., preferably in the range of> 0.9 equiv. to <1 equiv., take place. When reacted below 0.2 equiv. BF ₃ etherate, the effect is too low, while equivalent amounts above 2.0 equiv. can no longer be bound chemically to the body.

The lithiation and / or the reaction with BF ₃ etherate are preferably carried out while cooling the reaction mixture, for example to -78 ° C. After

Reaction with BF ₃ , the reaction solution can be warmed to ambient temperature and the

Solvent are removed. The trifluoroborate-substituted lithium pyrazolides can be obtained in good yield.

Examples and figures which serve to illustrate the present invention are given below.

Here are the figures: FIG. 1 shows the temperature-dependent ionic conductivities of lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 1-mod). Figure la) shows the ionic conductivity of LiPFAPl 1-mod in one

Solvent mixture of ethylene carbonate and dimethyl carbonate (EC: DMC, 1: 1), Figure lb) in propylene carbonate.

FIG. 2 shows a comparison of the temperature-dependent ionic conductivity of FIG

Trifluoroborate-substituted lithium pyrazolides and non-substituted lithium pyrazolides. FIG. 2 a) shows the ionic conductivity of lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP 1 -mod) and unsubstituted lithium pyrazoles lithium [3,5-bis (trifluoromethyl) pyrazolide]

(LiPFAPI 1) (EC: DMC, 1: 1), Figure 2b) shows the ionic conductivity of lithium [5- (perfluoroethyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 2-mod ) and lithium [5- (perfluoroethyl) -3- (trifluoromethyl) pyrazolide] (LiPFAP12) in adiponitrile (ADN).

Figure 3 shows the electrochemical stability of LiPFAPl 1-mod in propylene carbonate (PC).

FIG. 4 shows a corrosion measurement of lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP11-mod) in EC / DMC 1: 1 against aluminum as

Working electrode.

Figure 5 shows the specific capacity of an electrolyte containing 0.75 mol / kg

(Lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 1-mod) in EC / DMC 1: 1 using a lithium iron phosphate electrode.

Plotted is the loading and unloading capacity (left ordinate axis) and Coulomb's efficiency (right ordinate axis) against the number of charge / discharge cycles.

Figure 6 shows the specific capacity of an electrolyte containing 0.75 mol / kg

(Lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP11-mod) in EC / DMC 1: 1 using a lithium titanate (LTO) electrode.

The loading and unloading capacity (left ordinate axis) and Coulomb efficiency (right axis of ordinate) against the number of charge / discharge cycles.

Figure 7 shows the specific capacity of an electrolyte containing 0.75 mol / kg

(Lithium [3,5-bis (trifluoromethyl) -lH-pyrazol-1-yl] trifluoroborate (LiPFAPl 1-mod) in EC / DMC 1: 1 using a graphite electrode Plotted is the charge and discharge capacity (left ordinate axis) and Coulomb efficiency (right ordinate axis) versus the number of charge / discharge cycles.

Figure 8 shows the specific capacity of an electrolyte containing 0.75 mol / kg

(Lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP11-mod) in EC / DMC 1: 1 using a lithium nickel-cobalt-manganese oxide (NCM) electrode. Plotted is the loading and unloading capacity (left ordinate axis) and Coulomb's efficiency (right ordinate axis) against the number of charge / discharge cycles.

FIG. 9 shows a comparison of the cyclization of trifluoroborate-substituted lithium [5- (perfluoropropyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (electrolyte 2) and unsubstituted lithium [5 - (perfluorobutyl) - 3 - (trifluoromethyl) pyrazolide] (electrolyte 1). Figure 9a) shows the result of the C rate test, Figure 9b) shows the specific capacity.

Figure 10 shows the specific capacity of an electrolyte containing 0.75 mol / kg

(Lithium [3,5-bis (trifluoromethyl) -lH-pyrazol-1-yl] trifluoroborate (LiPFAPl 1-mod) in EC / DMC 1: 1 in a full cell The loading and unloading capacity is plotted (left axis of the ordinate) ) and efficiency (right ordinate axis) against the number of charge / discharge cycles.

FIG. 11 shows the result of the C-rate test of the cyclization of lithium [5

(perfluoroethyl) -3- (trifluoromethyl) -1 H -pyrazol-1-yl] trifluoroborate (LiPFAP 12-mod).

Figure 12 shows the specific capacity of the cyclization of lithium [5- (perfluoroethyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP 12-mod). Is applied the load and unload capacity (left ordinate axis) and efficiency (right ordinate axis) versus the number of charge / discharge cycles.

FIG. 13 shows the result of the C-rate test of the cyclization of lithium [5

(perfluoropropyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP13-mod).

FIG. 14 shows the specific capacity of the cyclization of lithium [5- (perfluoropropyl) -3-

(trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP13-mod). The loading and unloading capacity (left ordinate axis) and efficiency (right

Ordinate axis) against the number of charge / discharge cycles.

FIG. 15 shows the temperature-dependent ionic conductivities of lithium (3

(perfluorophenyl) -5- (trifluoromethyl) pyrazolyl) trifluoroborate (LiPFMPP-mod).

FIG. 16 shows the temperature-dependent ionic conductivities of lithium (3-methyl-5-)

(trifluoromethyl) pyrazolyl) trifluoroborate (LiPFAP0.5-mod).

Figure 17 shows the electrochemical stability of LiPFAP0.5-mod in propylene carbonate (PC). FIG. 18 shows the result of the C-rate test of the cyclization of lithium (3-methyl-5-)

(trifluoromethyl) pyrazolyl) trifluoroborate (LiPFAP0.5-mod).

FIG. 19 shows the specific capacity of the cyclization of lithium (3-methyl-5-)

(trifluoromethyl) pyrazolyl) trifluoroborate (LiPFAP0.5-mod). Plotted is the

Charging and discharging capacity (left ordinate axis) and efficiency (right

Ordinate axis) against the number of charge / discharge cycles.

FIG. 20 shows the result of the C-rate test of the cyclization of lithium (3

FIG. 21 shows the specific capacity of the cyclization of lithium (3- (perfluorophenyl) -5-

(trifluoromethyl) pyrazolyl) trifluoroborate (LiPFMPP-mod). The loading and unloading capacity (left ordinate axis) and efficiency (right

Ordinate axis) against the number of charge / discharge cycles.

Solvent: For synthesis, n-pentane was each dried over benzophenone / sodium and under an N 2 blanket gas atmosphere before use and distilled. The required amount was removed under protective gas with a dry and clean cannula, the solvent used for the crystallization chloroform pa (Sigma-Aldrich, 99.9%) was used directly without further pretreatment. Propylene carbonate (Merck, Selectilyte, 99.9%) was stored in a glove box at 4 ° C and taken there the required quantities.

Starting materials and reagents:

Hydrazine hydrate (64% hydrazine, 100% hydrazine hydrate, Acros), 3H H-perfluoropentane-2,4-dione (but, 99%), 3H, 3H-perfluorohexane-2,4-dione (Acros 90%), 3Ji3H-perfluoroheptane -2,4-dione (but, 97%), 3H-H-perfluorooctane-2,4-dione (but, 97%), and 3,5-bis (trifluoromethyl) pyrazole (Sigma-Aldrich, 99%) were added stored at a temperature of 4 ° C and used directly without further purification. n-Butyllithium (1.6 M in n-hexane, Acros) was stored at a temperature of 4 ° C and the volumes used under argon inert gas atmosphere removed.

example 1

Preparation of Lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate a) Preparation of 3,5-bis (trifluoromethyl) pyrazole

In a 100 mL two-necked flask with magnetic stirrer, septum and reflux condenser, 1 equivalent (equiv.) (5 g, 24.03 mmol) of 3i ^ 3H-perfluoropentane-2,4-dione were placed and dissolved in 15 mL of chloroform. To this solution was added slowly and with stirring 1.07 equiv. (1.287 g, 25.71 mmol) of hydrazine hydrate (64% hydrazine) was added dropwise through the septum. The reaction mixture was refluxed for one hour. After cooling the reaction mixture, 6 g of phosphorus pentoxide were added to the reaction mixture, the flask was resealed, as the solution heated after the addition of phosphorus pentoxide, and heated under reflux for a further six hours. Following was the while still slightly hot yellow from the white to gelatinous sediment, decant into a clean flask and wash the sediment once more with 5 mL of chloroform. The United Reaction Solutions were then crystallized at -32 ° C for three days. The crystals were filtered off in vacuo, washed with a little ice cold chloroform (-32 ° C.) and dried in vacuo for 2 minutes, since the crystals sublime significantly even at room temperature. For purification, the 3,5-bis (trifluoromethyl) pyrazole was then sublimed and thus obtained in the form of white crystal needles. b) reaction with BF ₃

1 equivalent of 3,5-bis (trifluoromethyl) pyrazole (2.05 g, 10 mmol) in 20 times the amount by weight of w-pentane was dissolved in a Schlenk flask under argon protective gas and the solution in an ice bath (dry ice / acetone) under Stirred to -78 ° C cooled. The cooling time was about 10 minutes. Then 1 equiv. a 1.6 molar solution of w-butyllithium in w-hexane slowly added dropwise to the cooled and well-stirred solution. The mixture was stirred for a further 20 minutes at -78 ° C and in

Follow this 1 equiv. BF ₃ etherate (diethyl ether-boron trifluoride, Sigma-Aldrich,> 46.5% BF ₃ ) was slowly added dropwise to the solution. The solution was warmed to room temperature overnight by thawing the dry ice-acetone bath. The solvent was in

Vacuum removed and the resulting white powdered lithium salt dried for a further 48 h in vacuo at room temperature (22 ° C ± 2 ° C). The yield was 98%.

Example 2

Preparation of lithium [5- (perfluoroethyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate a) Preparation of 5- (perfluoroethyl) -3- (trifluoromethyl) pyrazole

The preparation was carried out as described in Example la), wherein deviating 1 equiv. Dissolve 3H, 3H-perfluorohexane-2,4-dione (6.76 g, 26, 19 mmol) in 15 mL chloroform and then slowly and with good stirring 1.07 equiv. (1.403 g, 28.03 mmol) of hydrazine hydrate (64% hydrazine) was added dropwise through the septum. 5- (Perfluoroethyl) -3- (trifluoromethyl) pyrazole was obtained in the form of white crystals. b) reaction with BF ₃

The preparation was carried out as described in Example lb), wherein deviating 1 equiv. 5- (perfluoroethyl) -3- (trifluoromethyl) pyrazole was used. Lithium [5- (perfluoroethyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate was obtained as a white powder. The yield was 95%.

Example 3

Preparation of Lithium [5- (perfluoropropyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate a) Preparation of 5- (perfluoropropyl) -3- (trifluoromethyl) pyrazole

The preparation was carried out as described in Example la), wherein deviating 1 equiv. Dissolve 3H, 3H-perfluoroheptane-2,4-dione (2.00 g, 6.49 mmol) in 15 mL chloroform, then add 1.07 eq. (0.347 g, 6.94 mmol) of hydrazine hydrate (64% hydrazine) was added dropwise through the septum. 5- (Perfluoropropyl) -3- (trifluoromethyl) pyrazole was obtained as white crystals. b) reaction with BF ₃

The preparation was carried out as described in Example lb), wherein deviating 1 equiv. 5- (perfluoropropyl) -3- (trifluoromethyl) pyrazole was used. Lithium [5- (perfluoropropyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate was obtained as a white powder. The yield was 96%.

Example 4

Preparation of lithium [5- (perfluorobutyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate a) Preparation of 5- (perfluorobutyl) -3- (trifluoromethyl) pyrazole

The preparation was carried out as described in Example la), wherein deviating 1 equiv. Dissolve 3H, 3H-perfluorooctane-2,4-dione (2.95 g, 8.24 mmol) in 15 mL chloroform, then slowly add 1.07 eq. (0.44 g, 8.82 mmol) of hydrazine hydrate (64% hydrazine) was added dropwise through the septum. 5- (Perfluorobutyl) -3- (trifluoromethyl) pyrazole was obtained as white crystals. b) reaction with BF ₃

The preparation was carried out as described in Example lb), wherein deviating 1 equiv. 5- (perfluorobutyl) -3- (trifluoromethyl) pyrazole was used. Lithium [5- (perfluorobutyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate was obtained as a white powder. The yield was 93%.

Comparative Example 5

Preparation of non-BF ₃ substituted lithium pyrazoles 5.1 Lithium [3,5-bis (trifluoromethyl) pyrazolide]

1 equiv. of the obtained according to Example 1 from step a) of the synthesis, not substituted with BF ₃ 3,5-bis (trifluoromethyl) pyrazole was weighed under argon blanketing in a heated 100 mL Schlenk flask with magnetic stirrer and sealed with a septum. The weighed substance was then dissolved in 25 mL of anhydrous n-pentane. After complete dissolution, the solution was cooled with continued stirring to a temperature of -78 ° C in an isopropanol / dry ice cold bath. After cooling, the septum slowly added 1 equiv. n-Butyllithium (1.6 M in n-hexane) was added dropwise. The reaction mixture was stirred for 30 minutes at -78 ° C, then exchanged the isopropanol / dry ice cooling bath for an ice bath and the reaction mixture stirred for a further 30 minutes at 0 ° C. The fancy white salt was cannulated in transferred a reverse frit and separated there from the solvent. The salt was washed twice more with 10 mL of anhydrous n-pentane, dried in vacuo. Lithium [3,5-bis (trifluoromethyl) pyrazolide] was obtained in the form of a white powder. 5.2 Lithium [5- (perfluoroethyl) -3- (trifluoromethyl) pyrazolide]

The preparation was carried out as described in 5.1, exceptionally 1 equiv. of the obtained according to Example 2 from step a) of the synthesis 5- (perfluoroethyl) -3- (trifluoromethyl) pyrazole with 1 equiv. n-Butyllithium added and 20 mL of anhydrous w-pentane were used as a solvent. Lithium [5- (perfluoroethyl) -3- (trifluoromethyl) pyrazolide] was obtained in the form of a white powder.

5.3 Lithium [5 - (perfluorobutyl) -3 - (trifluoromethyl) pyrazolide]

The preparation was carried out as described in 5.1, exceptionally 1 equiv. of the obtained according to Example 3 from step a) of the synthesis 5- (perfluorobutyl) -3- (trifluoromethyl) pyrazole with 1.0 equiv. w-Butyllithium added and 20 mL of anhydrous w-pentane were used as a solvent. Lithium [5- (perfluorobutyl) -3- (trifluoromethyl) pyrazolide] was obtained in the form of a white powder.

Electrochemical characterization

Preparation of the electrolyte solutions:

Propylene carbonate (Merck, Selectilyte, 99.9%), adiponitrile (Sigma-Aldrich, 99%), or mixtures of 50% by weight of ethylene carbonate (EC, Merck, Selectilyte, 99.9%) and

50% by weight of dimethyl carbonate (DMC, Merck, Selectilyte, 99%) (EC: DMC, 1: 1) were initially charged. In these solvents or solvent mixture were according to the

Example 1 to 5 synthesized salts, so as to give the desired concentration of the respective lithium salt. The salts synthesized according to Example 5 were cooled to -20 ° C until use. Electrode production:

1 Preparation of active material suspensions

1.1 Lithium iron phosphate suspension

To prepare a lithium iron phosphate suspension, first 0.15 g of sodium carboxymethylcellulose (Na-CMC, WALOCEL ™ CRT 2000 PPA 12, Dow Wolff

Cellulosics) dissolved in 3 ml of deionized water and stirred for 2 hours. To this

Binder solution was added 300 mg of conductive carbon "carbon black" (Super P ^®, Timcal) and again stirred for 15 hours. Then, 2.6 g of

Lithium iron phosphate (Life ^Power® P2, Süd-Chemie) added and stirred until the homogeneity of the suspension. This conclusion was dispersed for one hour at 5000 rpm with a Hochenergierührer (T 18 ULTRA-TURRAX ^®, IKA). The solids content in the suspension had a composition of 85% by weight of lithium iron phosphate (LiFePO ₄ , LFP), 10% by weight of carbon and 5% by weight of binder.

1.2 Nickel-cobalt-manganese oxide (NCM) suspension

The suspension was prepared as indicated under 1.1, wherein as active material different lithium-nickel-cobalt-manganese oxide (NCM, TODA America, NM3100) was used. The Fe ststof fanteile in the suspension had a composition of 85 wt .-% NCM, 10 wt .-% carbon and 5 wt .-% binder on.

1.3 Lithium titanate (LTO) suspension

The suspension was prepared as indicated under 1.1. As active material was

Lithium titanate (LTO, Sigma-Aldrich, -325 mesh) used. The solids content in the suspension had a composition of 87% by weight LTO, 8% by weight carbon and 5% by weight binder.

1.4 graphite suspension The suspension was prepared as indicated under 1.1. As the binder, an Ir l mixture of styrene-butadiene rubber (SBR, ΜΓΓ Corporation) and NaCMC was used. The active material used was graphite (MAGD, Hitachi Chemical). The solids content in the suspension had a composition of 90% by weight graphite (MAGD), 5% by weight carbon and 5% by weight binder mixture.

2 coating

2.1 coating on aluminum

The suspensions 1.1, 1.2 and 1.3 were coated on aluminum foil. For this purpose, this film was first etched in 5 wt .-% aqueous KOH solution (60 ° C, 60 s, d _before h _e r = 20 μιη), rinsed with pure water (Millipore) and then with a knife with the suspension, for example with a wet film thickness of 120 μιη coated. The thickness of the dried layer was then 22 μιη to 24 μιη. The films were at 80 ° C for 15 hours

dried. Subsequently, round electrodes were punched out with a diameter of 12 mm and dried for 48 hours at 120 ° C and 10 ^" mbar.

The area loading for LFP electrodes was 2.85 mg cm ^" total, corresponding to 2.42 mg cm - ^" 2 LFP. The surface loading for LTO electrodes was 3.5 mg cm - ^" 2, corresponding to

3.04 mg cm - ^" 2 LTO The area loading for NCM electrodes was 2.75 mg cm - ^" 2, corresponding to 2.34 mg cm ^"2 NCM.

2.2 Coating on copper

In contrast to 2.1, the graphite electrodes were applied to untreated copper foil.

The area loading for graphite electrodes was 5.0 mg cm - ^" 2, corresponding to 4.5 mg cm - ^" 2 graphite.

Lithium films: From lithium foil (99.99%, Rockwood Lithium) were round electrodes with a

Diameter of 12 mm and a thickness of 0.5 mm punched and used as a counter electrode (CE). Example 6

Measurement of temperature-dependent ionic conductivity via impedance

The salt lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate prepared according to Example 1 was dissolved under argon protective gas in a mixture of ethylene carbonate and dimethyl carbonate (in a weight ratio of 1: 1). Aliquots of this solution were diluted with further solvent mixture (EC / DMC 1: 1) to form a concentration series. Measured in each case 350 μΐ _^ in liquid impedance cells, which were constructed according to document DE 10 2013 004 204.6 "Proto-MDE cell." The impedance measurements were carried out with a potentiostat Autolab PGSTAT302N® with additional FRA32 module from Deutsche Metrohm. Bad was used the thermostat FP88-ME of the company Julabo Labortechnik GmbH The data acquisition and evaluation was with the programs NOVA 1.10.3, ZView version 2.9c ^® , and

OriginPro ^® 8 SRO v8.5.0 SRI. The frequency range of the impedance measurement was in the range of 10 to 20,000 Hz, the voltage amplitude was 40 mV. The

Temperature program provided that the sample started at a temperature of -20 ° C.

Subsequently, the sample was heated in 5 ° C increments up to 90 ° C.

The measurement was carried out for concentrations of 0.5 mol / kg, 0.75 mol / kg, 1 mol / kg and 1.25 mol / kg of lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate in a 1: 1 mixture of ethylene carbonate and dimethyl carbonate (EC: DMC, 1: 1) and 0.6 mol / kg, 0.8 mol / kg, 1 mol / kg and 1.2 mol / kg of lithium [3, 5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate in propylene carbonate. The temperature-dependent ionic conductivities of the salt lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 1-mod) in the common battery solvent mixture EC / DMC in the ratio 1: 1 is shown in FIG. shown. As the Figure la) can be removed, the ionic conductivity was at a concentration of 0.75 mol / kg of solvent 1 - 10 ^"2 S / cm at 90 ° C, 5.4 x ^{10" 3} S / cm at 25 ° C and 2 · 10 ^" S / cm at -20 ° C. The ionic conductivity of lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate is thus comparable to the very high conductivity of the commercial system 1 mol / kg of LiPF ₆ in EC / DMC 1: 1. At lower temperatures, lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate shows even higher

Conductivity as the commercial LiPFö system.

FIG. 1 b) shows the temperature-dependent ionic conductivities of lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 1-mod) in propylene carbonate. As can be seen from FIG. 1b), the trifluoroborate-substituted lithium pyrazolide at a concentration of 0.8 mol / kg also exhibited similarly high conductivities in propylene carbonate, for example 4-10 ^"J s / cm at 25 ° C.

The measurement of the temperature-dependent ionic conductivity was carried out for lithium [5- (perfluoroethyl) -3- (trifluoromethyl) -1 H -pyrazol-1-yl] trifluoroborate (LiPFAP 12-mod),

Lithium [5- (perfluoropropyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP 13-mod) and lithium [5- (perfluorobutyl) -3- (trifluoromethyl) -1H-pyrazole-1-one yl] trifluoroborate (LiPFAP14-mod). The results of the measurements are in the following Table 1

summarized: Table 1: Results of ionic conductivities via impedance measurement

Table 1 shows that the trifluoroborate-substituted lithium pyrazolides show high lithium ion conductivity even at very low temperatures.

Example 7

Comparison of the temperature-dependent ionic conductivity with non-trifluoroborate-substituted pyrazoles The temperature-dependent ionic conductivity of the trifluoroborate-substituted pyrazoles lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 1-mod) and lithium [5 - (Perfluoroethyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 2-mod) was unsubstituted with the conductivity of the Comparative Example 5 prepared Lithium pyrazoles lithium [3,5-bis (trifluoromethyl) pyrazolide] (LiPFAPl l) and lithium [5- (perfluoroethyl) -3- (trifluoromethyl) pyrazolide] (LiPFAP12) compared.

For this purpose, in each case 1 molar solutions LiPFAPl l and LiPFAPl l-mod were prepared in EC / DMC 1: 1, and LiPFAP12 and LiPFAP12-mod in adiponitrile (ADN) and in one

Temperature range from -20 ° C to +90 ° C measured as described in Example 6. The frequency range was between 10 Hz and 20000 Hz measuring point number = 20 per temperature) with a voltage of 40 mV.

The results of the measurements for 1 mol / kg of lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP11-mod) and lithium [3,5-bis (trifluoromethyl) pyrazolide]

(LiPFAPI 1) are summarized in the following Table 2:

Table 2

The results of the measurements for 1 mol / kg of lithium [5- (perfluoroethyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 2-mod) and lithium [5- (perfluoroethyl) -3- ( trifluoromethyl) pyrazolide] (LiPFAPl 2) in adiponitrile (ADN) are summarized in the following Table 3: Table 3

A comparison of the conductivities of the lithium salts shows that the modification according to the invention with trifluoroborate increased the conductivity of both salts by about half a decade to one decade.

FIGS. 2a) and 2b) show a graph of the temperature-dependent ionic conductivities of lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP11-mod) and lithium [3,5-bis (trifluoromethyl) pyrazolide]

(LiPFAPl l) in the solvent mixture EC / DMC in the ratio 1: 1 and 1 mol / kg

Lithium [5- (perfluoroethyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP12-mod) and lithium [5- (perfluoroethyl) -3- (trifluoromethyl) pyrazolide] (LiPFAP12) in adiponitrile ( ADN). Figures 2a) and 2b) can also be seen that the modification with trifluoroborate significantly increased the conductivity of both salts.

Example 8

Measurement of the Electrochemical Stability of Lithium [3,5-bis (trifluoromethyl) -1-H-pyrazol-1-yl] trifluoroborate The electrochemical stability was determined by means of linear sweep voltammetry (LSV) of the salt lithium synthesized according to Example 1 [3 5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP11-mod) in a solution at a concentration of 1 mol / kg in propylene carbonate (PC). Of the

Voltage feed was 1 mV / s. Measured in each case 350 μΐ _^ in three-electrode stability measuring cells, which were constructed according to document DE 10 2013 004 204.6 "Proto-MDE cell"

Working electrodes were designed for measurements in the potential range below the open circuit voltage of copper and platinum above. The diameter of the circular

Working electrodes was 1 mm. The measurements were made against a lithium pseudo reference electrode and a copper counterelectrode. The measurements were carried out at 22 ° C with a potentiostat (Autolab PGSTAT302N ^®, German Metrohm). The data were acquired with the program NOVA ^® 1.10.3 and saved as ASCII files. The evaluation was done with the program OriginPro 8.5 SRI.

The result of the measurements is shown graphically in FIG. As can be seen from FIG. 3, the anion of the salt LiPFAPl 1-mod showed an electrochemical oxidation stability of up to 5 V. Li / Li ⁺ . The recognizable in the figure 3

Reduction reactions were caused by the solvent used as propylene carbonate (PC). The formation of a passivation layer (SEI) on the electrode prevented further reduction of the propylene carbonate.

Example 9

Corrosion measurements on aluminum current collectors

The measurement to determine a possible corrosion of aluminum current collectors was carried out in a three-electrode stability cells as described in Example 8. The working electrodes were made of aluminum in these measurements. The diameter of the circular aluminum electrodes was 1 mm. It became a solution to a

Concentration of 1 mol / kg of lithium [3,5-bis (trifluoromethyl) -lH-pyrazol-l-yl] trifluoroborate (LiPFAPl 1-mod) in the solvent mixture EC / DMC in the ratio 1: 1 used. Five cycles of a cyclic voltammetry measurement (CV measurement, CV = cyclic voltammetry) were carried out.

The result of the measurement is shown graphically in FIG. As can be seen from FIG. 4, the corrosion measurement of the system showed lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP11-mod) in EC / DMC 1: 1 against aluminum as the working electrode first in the first cycle a high current density plateau. The following cycles showed successive decreases of the peak intensities, which speaks for the formation of a passivation layer and thus for a suppression of the

Aluminum corrosion.

Example 10

Cyclization of a lithium iron phosphate electrode in an electrolyte containing

Lithium [3,5-bis (trifluoromethyl) - ΙΗ-pyrazol-1-yl] trifluoroborate

The cyclization was carried out in three-electrode Swagelok ^® cells with lithium metal foils as the counter and reference electrodes (CE, RE) and lithium iron phosphate (LFP) electrode as a working electrode (WE). The assembly of the cell was done in one with a

Inert gas atmosphere on argon-filled glove box with an oxygen content below 0.6 ppm and water content less than 0.2 ppm. The experiments were performed using a Series 4000 battery tester (Maccor). The cells were grown using two nonwovens FS 2190 (d ~ 1.2 mm, 0 = 13 mm, Freudenberg) as a separator and 50 μL liquid

Electrolytes built. The electrolyte used was a 0.75 mol / kg solution of (lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 1-mod) in a 1: 1 mixture, based on the Weight, of ethylene carbonate and dimethyl carbonate, EC / DMC 1: 1 used. The constant current (CC) was related to the LFP content of the electrode and the specific capacity of 170 mAh g ^{"1 was} taken into account The cells were cycled between 2.8 and 4.2 V vs. Li / Li ⁺ , the potential being The cyclization was first carried out at different charge / discharge rates of 0, IC, 0.5C, IC, 2C, 3C, 4C, and 5C, whereby the electrolyte containing 0.75 mol / kg ( Lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 1-mod) in EC / DMC 1: 1 in the three-electrode arrangement with LFP as

Active material has a very high capacity of 110 mAh / g at 5C even at high C rates. The current density was about 2, 1 mA / cm ² .

The cell was further tested for this constant charge / discharge rate procedure by IC. The result of the cyclization with constant charging / discharging rate is shown graphically in FIG. As can be seen from Figure 5, a stable charge / discharge capacity of about 150 mAh / g was observed for over 200 cycles. The Coulomb efficiency of the charge / discharge test was consistently over 99%.

Further investigations showed that even at very high C-rates, such as 50C, a high capacity of 58 mAh / g could be achieved. The current density was approx.

21 mA / cm ² . Up to 100C charge / discharge rates were possible. In a subsequent study with a constant charge / discharge rate of 40C, a stable charging

/ Discharge capacity of about 70 mAh / g observed for over 50 cycles. The Coulomb efficiency of the charge / discharge test was always over 98%.

Example 11

Cyclization of a lithium titanate (LTO) electrode in an electrolyte containing

Lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate The cyclization was carried out in three-electrode Swagelok cell as described in Example 10, wherein a lithium titanate (LTO) electrode was used as the working electrode (WE). The electrolyte used was again a 0.75 mol / kg solution of (lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP1-mod) in EC / DMC 1: 1 Cells were cycled between 1.0 and 2.0 V vs. Li / Li ⁺ The cyclization was first performed at various charge / discharge rates of 0.1C, 0.5C, IC, 2C, 3C, 4C, and 5C. Then, the constant current was set to IC charging / discharging to obtain the electrolyte containing 0.75 mol / kg (lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP1-mod) in EC / DMC 1: 1 with lithium titanate as

Active material has a capacity of 142 mAh / g at 5C. The current density was about 3.5 mA / cm ² .

In the subsequent constant charge / discharge rate study of IC, a stable charge / discharge capacity of about 160 mAh / g was observed for over 190 cycles. The Coulomb efficiency of the charge / discharge test was consistently over 99%. The result is shown graphically in FIG.

Example 12

Cyclization of a graphite electrode in an electrolyte containing lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate

Cyclization was as described under Example 10 in three-electrode Swagelok ^® cell, using a graphite electrode as a working electrode (WE) was used. The electrolyte used was again a 0.75 mol / kg solution of (lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 1-mod) in EC / DMC 1: 1 Cells were cycled between 0.02 and 1.5 V vs. Li / Li ⁺ The cyclization was first performed at various charge / discharge rates of 0.1C, 0.5C, IC, 2C, 3C, 4C and 5C After reaching the cell voltage of 0.02 V, the charge was kept constant for the duration of the galvanostatic charge, provided that the current did not fall below one fifth of the charge Electricity at IC fell. Subsequently, with the same charging method, IC was continuously charged and discharged with IC. The comparative electrolyte used was a solution of 1 mol / kg of LiPF ₆ in EC / DEC 3: 7. The electrolyte containing 0.75 mol / kg (lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 1-mod) in EC / DMC 1: 1 achieved significantly with graphite as the active material The current density at 5C was in each case about 8 mA / cm ^2, whereby 146 mAh / g of 372 mAh / g were achieved for the described electrolyte, whereas with 1 mol / kg LiPF ₆ in EC / DEC 3 : 7 at 5C only about 122 mAh / g were reached.

In the subsequent constant charge / discharge rate study of IC, a stable charge / discharge capacity of approximately 372 mAh / g (corresponding to specific capacity) was observed for over 25 cycles. The Coulomb efficiency of the charge / discharge test was consistently over 99%. The result is shown graphically in FIG.

Example 13

Cyclization of a lithium-nickel-cobalt-manganese oxide (NCM) electrode in one

Electrolytes containing lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate

The cyclization was carried out in three-electrode cell Swagelok ^® as described in Example 10, whereby a lithium-nickel-cobalt-manganese oxide (NCM) electrode as the

Working electrode (WE) was used. The electrolyte used was again a 0.75 mol / kg solution of (lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 1-mod) in EC / DMC 1: 1 Cells were cycled between 3.0 and 4.3 V vs. Li / Li ⁺ Cyclization was first performed at different charge / discharge rates of 0, 1C, 0.5C, IC, 2C, 3C, 4C, and 5C. Subsequently, the constant current was set to IC charge / discharge. The electrolyte containing 0.75 mol / kg (lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAPl 1-mod) in EC / DMC 1: 1 was obtained with lithium nickel chloride. Cobalt manganese oxide (NCM) as an active material at high C rates of 5C has a very good capacity of 92 mAh / g, with a current density of 2.2 mA / cm ² .

In the subsequent constant charge / discharge rate study of IC, a stable charge / discharge capacity of about 130 mAh / g was observed for over 25 cycles. The Coulomb efficiency of the charge / discharge test was consistently over 99%. The result is shown graphically in FIG.

Example 14

Comparison of the charge / Entladeuntersuchungen with non trifluoroborate-substituted pyrazoles of the comparison of the cyclization was carried out in three-electrode cell Swagelok ^® as described in Example 10 with lithium iron phosphate (LFP) as the working electrode. As described in Example 10, a C-rate test was first performed. Charge / discharge rates of 0.1C, 0.5C, IC, 2C, 3C, 4C, and 5C were used. Subsequently, the constant current was set to IC charge / discharge.

The electrolyte used was a 0.7 mol / kg solution of lithium [5- (perfluoropropyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP13-mod) in a 1: 1 mixture, based on the weight used of ethylene carbonate and dimethyl carbonate, EC / DMC 1: 1 (electrolyte 2). As a comparative electrolyte (electrolyte 1), a 0.7 mol / kg solution of lithium [5- (perfluoropropyl) -3- (trifluoromethyl) pyrazolide] (LiPFAP13) in a 1: 1 mixture by weight of ethylene carbonate and Dimethyl carbonate, EC / DMC 1: 1. The result of the C-rate test is shown graphically in FIG. 9a). As can be seen from FIG. 9a), electrolyte 2 achieved a capacity of about 152 mAh / g at 0.1 C, while electrolyte 1 only reached a capacity of 115 mAh / g. Up to 5C, the capacity of the electrolyte 2 only dropped to about 125 mAh / g while it decreased in comparison electrolyte 1 to a capacity of less than 3 mAh / g.

The result of the subsequent constant charge / discharge rate study of IC is shown graphically in Figure 9b). For the electrolyte containing the lithium pyrazolide (electrolyte 2) substituted according to the invention with trifluoroborate, a stable charge / discharge capacity was observed at IC of about 145 mAh / g for more than 250 cycles. The

Coulomb efficiency of the charge / discharge test was over 98%. For the

Comparative Electrolyte 1, a charge / discharge capacity of about 45 mAh / g was observed for 100 cycles. The capacity dropped significantly in less than 30 mAh / g in a further 150 cycles. The Coulomb efficiency of the charge / discharge test was over 98%.

It can be seen from FIG. 9b) that the higher conductivity of the electrolyte 2 resulted in a significantly higher discharge capacity compared to the electrolyte 1. This was manifested both in the range of higher C rates (5C) and in the constant charging / discharging of cells (IC). As FIG. 9b) further shows, the discharge capacity of the comparative electrolyte 1 was not stable. It decreased significantly after 200 cycles. It is believed that this is due to a side reaction of the pyrazole with the solvent mixture

Dimethlycarbonate / ethylene carbonate was caused, which is prevented by the inventive substitution with trifluoroborate.

Example 15

Cyclization of a full cell The full cells were made from LFP and graphite electrodes in a two-electrode arrangement. The electrolyte used was a 0.75 mol / kg solution of (lithium [3,5-bis (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate in a 1: 1 mixture, by weight, of ethylene carbonate and dimethyl carbonate , EC / DMC 1: 1.

First, the cell was formed at a low C rate of 0.2C. Subsequently, the cell was continuously charged and discharged for 25 cycles with IC. The result of the cyclization of the full cell is shown graphically in FIG. As can be seen from FIG. 10, after the formation a largely stable cyclization behavior has been observed for IC. The irreversible ones occurring in the first cycle

Losses of about 30% are attributed to the low mass loadings of the LFP electrode in relation to the graphite. This shows that the electrolyte containing a 0.75 mol / kg solution of a trifluoroborate-substituted lithium pyrazolide also achieved a promising result in a full cell.

Example 16

Charge / Entladeuntersuchungen with lithium [5- (perfluoroethyl) -3- (trifluoromethyl) -lH-pyrazol-l- yl] trifluoroborate The cyclization was carried out in three-electrode cell Swagelok ^® as described in Example 10 with lithium iron phosphate as a working electrode. By contrast, thicker electrodes were used whose mass loading was greater and averaged 8 mg. As described in Example 10, a C-rate test was first performed. Charge / discharge rates of 0.1C, 0.5C, IC, 2C, 3C, 4C, and 5C were used. Subsequently, the constant current was set to IC charge / discharge.

The electrolyte used was a 0.6 mol / kg solution of lithium [5- (perfluoroethyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP12-mod) in a 1: 1 mixture, by weight, of ethylene carbonate and dimethyl carbonate, EC / DMC 1: 1. The result of the C-rate test is shown graphically in FIG. As the figure 11 can be removed, scored Lithium [5- (perfluoroethyl) -3- (trifluoromethyl) -lH- pyrazol-l-yl] trifluoroborate a capacity of about 142 g mAh- ^"1 at 0.1C. To 5C the capacity only dropped to about 78 mAhg ^"1 . The result of the subsequent constant charge / discharge rate study of IC is shown in FIG. A stable charge / discharge capacity was observed for IC of about 110 mAhg ^"1 over 500 cycles

Coulomb efficiency of the charge / discharge test was over 98%. Example 17

Charge / discharge studies with lithium [5- (perfluoropropyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate

The cyclization was carried out in three-electrode Swagelok ^® cell as described in Example 10 with lithium iron phosphate as the working electrode. By contrast, thicker electrodes were used whose mass loading was greater and averaged 8 mg. As described in Example 10, a C-rate test was first performed. Charge / discharge rates of 0.1C, 0.5C, IC, 2C, 3C, 4C, and 5C were used. Subsequently, the constant current was set to IC charge / discharge.

The electrolyte used was a 0.4 mol / kg solution of lithium [5- (perfluoropropyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate (LiPFAP13-mod) in a 1: 1 mixture, based on the weight of ethylene carbonate and dimethyl carbonate, EC / DMC 1: 1. The result of the C-rate test is shown graphically in FIG. As the figure 13 can be removed, scored Lithium [5- (perfluoropropyl) -3- (trifluoromethyl) - LH-pyrazol-l-yl] trifluoroborate at 0.1C a capacity of about 147 g mAh- ^"1 to 5C. the capacity only dropped to approx. 62 mAhg ^"1 . The result of the subsequent constant charge / discharge rate study of IC is shown in FIG. It became a stable Charging / discharging capacity with IC of about 110 mAhg ^"1 over 500 cycles observed

Coulomb efficiency of the charge / discharge test was over 98%.

Example 18

Preparation of Lithium (3- (perfluorophenyl) -5- (trifluoromethyl) pyrazolyl) trifluoroborate a) Preparation of 4,4,4-trifluoro-1- (perfluorophenyl) butane-1,3-dione

5.47 g (56.92 mmol, 0.9 eq) of sodium tert-butoxide (but) were weighed into a heated 100 mL Schlenk flask under argon protective gas atmosphere and 60 mL of dry pentane were added. To the stirred, yellowish suspension at 0 ° C was added 10.36 g (72.88 mmol, 1 eq.) Of ethyl trifluoroacetate (Chempur). After 10 minutes, 13.77 g (65.54 mmol, 1 eq.) Of 2 ', 3', 4 ', 5', 6'-pentafluoroacetophenone (but) were added dropwise at 0 ° C. The reaction mixture already became clear during the addition and discolored inside

Seconds from pale yellow to orange yellow. There followed a quick fail of a white one

Precipitate. After stirring for 1 h at room temperature (RT), the

Solvent filtered through a glass frit Por 4 and washed with 80 mL of pentane. The solid was transferred to a beaker and distilled in about 150 mL. Dissolved water. The solution was transferred to a 250 mL separatory funnel with Teflon stopcock and slowly added dropwise to a strongly stirred copper sulfate pentahydrate solution (9.63 g in 150 mL distilled H ₂ O). The result was a light green precipitate which was filtered off with suction through a glass frit Por 4, with dist. H ₂ 0 washed and dried for 2 days in a vacuumized desiccator over CaCl ₂ . The dried solid was treated with 3 mL concentrated sulfuric acid in a 100 mL Schlenk flask. It was stirred for about 10 minutes until the green complex gave way to a white precipitate and a clear solution. The clear liquid was separated by distillation (6.6 x 10 ^"2 mbar, 55 ° C) separated from the solids and at -78 ° C (C0 ₂ / acetone cooling bath) was collected in a flask. B) Preparation of 3- (perfluorophenyl ) -5- (trifluoromethyl) -1H-pyrazole 12.74 g (41.62 mmol, 1 eq.) Of the 4,4,4-trifluoro-1- (perfluorophenyl) butane-1,3-dione obtained from step a) were weighed into a 100 ml Schlenk flask and 60 ml

Chloroform (prolabo) added. A reflux condenser was placed on the flask. To the stirring solution, 1.90 g (37.96 mmol, 0.9 eq.) Of hydrazine hydrate (but) was slowly added dropwise through the Schlenk valve of the flask. The reaction solution became cloudy and hot.

After stirring for 30 min., 3 tl of P ₄ O _{10 were} added over 10 min. It was refluxed for 3 hours. In the flask was next to the remaining P ₄ O _10, a crystalline solid can be seen. The contents of the reaction flask were washed with approx. 300 mL chloroform and 200 mL dist. Dissolved H ₂ 0, transferred to a 1000 mL separatory funnel with Teflon tap and shaken vigorously. The organic phase was separated from the aqueous and shaken twice more with chloroform. For purification by recrystallization, the organic phases were collected in a 500 ml one-necked flask and the solvent was removed on a rotary evaporator. The residual solid was redissolved in 45 mL of warm chloroform and allowed to stand at RT for one hour. It formed crystals. The flask was cooled for 24 h at -36 ° C in the freezer. The resulting crystals were filtered with suction through a Por 4 glass frit and washed with chloroform which was cooled with a C0 ₂ / acetone cooling bath. The product was sublimed at 160 ° C and under reduced pressure. c) Preparation of lithium (3- (perfluorophenyl) -5- (trifluoromethyl) pyrazolyl) trifluoroborate

3.07 g (10.15 mmol, 1 eq.) Of the 3- (perfluorophenyl) -5- (trifluoromethyl) -1-pyrazole obtained from step b) were weighed into a heated 100 mL Schlenk flask under argon protective gas atmosphere and 55 mL added dry diethyl ether. The clear solution was cooled to -78 ° C (C0 ₂ / acetone cold bath). 6.34 ml (10.15 mmol, 1 eq.) Of a 1.6 molar solution of n-butyllithium in hexane (Sigma-Aldrich) were added dropwise and the cloudy solution was stirred for 2 h. 1.25 mL (10.15 mmol, 1 eq.) Trifluoroborane diethyl ether complex (Sigma-Aldrich) was added. After 3 h, the reaction mixture was brought to RT and stirred for a further 12 h. The solvent was removed in vacuo and a fine, white powder remained in the reaction flask. This solid was dried at 120 ° C and 7.5-10 ^" mbar for 14 h.

Example 19

Preparation of lithium (3-methyl-5- (trifluoromethyl) pyrazolyl) trifluoroborate a) Preparation of 3-methyl-5- (trifluoromethyl) pyrazole starting from 1,1,1-trifluoroacetylacetone

In a 100 mL two-necked flask with magnetic stirrer, septum and

Reflux condenser 1 equiv. (14.54 g, 94.34 mmol) of trifluoroacetylacetone (but) and dissolved in 50 ml of chloroform (Prolabo). To this solution was added slowly with stirring 0.95 equiv. (4.49 g, 89.62 mmol) of hydrazine hydrate (but) added dropwise through the septum. The reaction mixture was stirred for 1 hour at room temperature and refluxed for a further 1 hour. This was followed by the slightly yellow reaction mixture with 10 g

Phosphorus pentoxide (Sigma-Aldrich) and heated under reflux for a further 2 hours. After cooling, the resulting suspension was mixed with 50 ml of water and stirred until the phosphorus pentoxide has completely dissolved. The chloroform phase was separated off and the aqueous phase was extracted by shaking again with 50 ml of chloroform. The combined phases were cooled at -20 ° C in the freezer, so that the starting material could be crystallized for two days. The resulting crystals were filtered off and washed with 20 ml of cold chloroform. Subsequently, the crystals were sublimed in vacuo at 5-10 ^" mbar and a temperature of 140 ° C. There were 10.20 g of white

Preserved crystal needles. b) Preparation of lithium (3-methyl-5- (trifluoromethyl) pyrazolyl) trifluoroborate

3.0 g (19.99 mmol, 1 eq.) Of the 3-methyl-5- (trifluoromethyl) -1H-pyrazole obtained from step a) were weighed into a heated 100 mL Schlenk flask under an argon protective gas atmosphere and 30 mL dry diethyl ether added. The clear solution was at -78 ° C (C0 ₂ / acetone cold bath) cooled. 12.49 ml (19.99 mmol, 1 eq.) Of a 1.6 molar solution of n-butyllithium in hexane (Sigma-Aldrich) were added dropwise and the turbid solution was stirred for 2 h. 2.47 mL (19.99 mmol, 1 eq.) Trifluoroborane diethyl ether complex (Sigma-Aldrich) was added. After 3 h, the reaction mixture was brought to RT and stirred for a further 12 h. The solvent was removed in vacuo leaving a fine, white powder in the reaction flask. This solid was dried at 120 ° C and 7.5-10 ^" mbar for 14 h.

Example 20

Measurement of temperature-dependent ionic conductivity via impedance

The salts lithium (3- (perfluorophenyl) -5- (trifluoromethyl) pyrazolyl) trifluoroborate prepared according to Examples 18 and 19 and lithium (3-methyl-5- (trifluoromethyl) pyrazolyl) trifluoroborate were mixed from ethylene carbonate and dimethyl carbonate (in the weight ratio 1: 1) dissolved and created concentration series. The measurement of the temperature-dependent ionic conductivity was carried out in liquid-impedance cells as described in Example 6. Measurements were carried out in each case for concentrations of 0.2, 0.4, 0.6, 0.8, 1 and 1.2 mol / kg of the respective salt. The temperature-dependent ionic conductivities of the salt lithium (3- (perfluorophenyl) -5- (trifluoromethyl) pyrazolyl) trifluoroborate (LiPFMPP-mod) is shown in FIG. 15 and that of lithium (3-methyl-5- (trifluoromethyl) pyrazolyl) trifluoroborate (LiPFAP0.5-mod) is shown in FIG. As can be seen from Figure 15, the ionic

Conductivity of lithium (3- (perfluorophenyl) -5- (trifluoromethyl) -pyrazolyl) -trifluorborat (LiPFMPP-mod) at a concentration of 0.8 mol / kg of solvent 6.8 x 10 ^"S / cm at 80 ° C , 3.3 × 10 ^-3 S / cm at 25 ° C. and 6.5 × 10 ^-4 S / cm at -20 ° C. As can be seen from FIG. 16, the ionic conductivity of lithium methyl-5- (trifluoromethyl) pyrazolyl) trifluoroborate (LiPFAP0.5-mod) at a concentration of 0.8 mol / kg Solvent 6.6 x 10 ^-3 S / cm at 80 ° C, 2.9 x 10 ^-3 S / cm at 25 ° C, and 8.8 x 10 ⁴ S / cm at -20 ° C. Set both salts Thus, a good ionic conductivity available, wherein the ionic conductivity of the lithium (3- (perfluorophenyl) -5- (trifluoromethyl) pyrazolyl) trifluoroborate exceeded that of the methyl-substituted salt.

Example 21

Measurement of electrochemical stability

The electrochemical stability of the salts prepared according to Examples 18 and 19 was lithium (3- (perfluorophenyl) -5- (trifluoromethyl) pyrazolyl) trifluoroborate and lithium (3-methyl-5- (trifluoromethyl) pyrazolyl) trifluoroborate in solutions with a concentration of 1 mol / kg salt in propylene carbonate by linear feed voltammetry measured as described in Example 8. Both salts showed good electrochemical

Oxidation stability. In particular, lithium (3-methyl-5- (trifluoromethyl) pyrazolyl) trifluoroborate (LiPFAP 0.5-mod) showed very good electrochemical oxidation stability, as shown in FIG.

Example 20

Charge / discharge studies with lithium (3-methyl-5- (trifluoromethyl) pyrazolyl) trifluoroborate

The cyclization was carried out in three-electrode Swagelok ^® cell as described in Example 10 with lithium iron phosphate as the working electrode. By contrast, thicker electrodes were used whose mass loading was greater and averaged 8 mg. As described in Example 10, a C-rate test was first performed. Charge / discharge rates of 0.1C, 0.5C, IC, 2C, 3C, 4C, and 5C were used. Subsequently, the constant current was set to IC charge / discharge. The electrolyte was a 0.8 mol / kg solution of lithium (3-methyl-5- (trifluoromethyl) pyrazolyl) trifluoroborate (LiPFAP0.5-mod) in a 1: 1 mixture by weight of Ethylene carbonate and dimethyl carbonate, EC / DMC 1: 1. The result of the C rate test is shown graphically in FIG. As can be seen in FIG 18, scored lithium (3-methyl-5- (trifluoromethyl) -pyrazolyl) at 0.1C -trifluorborat a capacity of about 147 mAh g ^"1 to 5C, the capacity decreased only to approx. 51 mAh-g ^"1 . The result of the subsequent constant rate charge / discharge rate study of IC is shown in FIG. On average, a charge / discharge capacity at IC of about 103 mAh-g ^{-1 was} observed over 500 cycles, and Coulomb efficiency of the charge / discharge test was over 98%.

Example 23

Charge / discharge investigations with lithium (3 - (perfluorophenyl) - 5 - (trifluoromethyl) pyrazolyl) trifluoroborate

As the electrolyte, a 0.4 mol / kg solution of lithium (3- (perfluorophenyl) -5- (trifluoromethyl) pyrazolyl) trifluoroborate (LiPFMPP-mod) in a 1: 1 mixture by weight of Ethylene carbonate and dimethyl carbonate, EC / DMC 1: 1. The result of the C-rate test is shown graphically in FIG. As can be seen from Figure 20, lithium (3- (perfluorophenyl) -5- (trifluoromethyl) pyrazolyl) trifluoroborate achieved a capacity of about 148 mAh-g- ¹ at 0.1 ° C. Up to 5 ° C, the capacity only decreased to about 61 mAh g ^'1. The result of the subsequent examination at a constant charge / discharge rate of IC is shown in the figure 21st It has an average charge / discharge capacity at IC of approximately 105 mAh-g ^"1 via 450 cycles observed. The Coulomb efficiency of the charge / discharge test was over 98%.

Overall, these results indicate that the trifluoroborate-substituted lithium pyrazolides provide highly efficient conducting salts for lithium-based energy storage. Thus, the trifluoroborate-substituted lithium pyrazolides show high lithium ion conductivity even at very low temperatures and high Coulomb efficiency. Furthermore, the trifluoroborate-substituted lithium pyrazolides show high chemical and electrochemical stability. The trifluoroborate-substituted lithium pyrazolides thus offer an alternative to replace LiPF ₆ as conductive salt in lithium-ion batteries.

Claims

1. trifluoroborate-substituted lithium pyrazolide according to the general formula (1) given below

wherein:

_, R is the same or independently selected from the group comprising linear or branched alkyl or cycloalkyl groups having 1 to 12 carbon atoms, linear or branched, perfluorinated or partially fluorinated alkyl or cycloalkyl groups having 1 to 12 carbon atoms and / or perfluorinated or partially fluorinated phenyl.

2. trifluoroborate-substituted lithium pyrazolide according to claim 1, characterized

Fl F2

in that R and R are each the same or independently selected from the group comprising linear or branched perfluorinated alkyl or cycloalkyl groups having 1 to 6 carbon atoms and / or pentafluorophenyl, preferably a linear perfluorinated alkyl group having 1 to 6 Carbon atoms.

3. trifluoroborate-substituted lithium pyrazolide according to claim 1 or 2, characterized in that the trifluoroborate-substituted lithium pyrazolide is selected from the group comprising:

Lithium [3, 5-bis (trifluoromethyl) -1-H-pyrazol-1-yl] trifluoroborate,

Lithium [5- (perfluoroethyl) -3- (trifluoromethyl) -lH-pyrazol-l-yl] trifluoroborate,

Lithium [5- (perfluoropropyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate and / or lithium [5- (perfluorobutyl) -3- (trifluoromethyl) -1H-pyrazol-1-yl] trifluoroborate ,

4. Use of a trifluoroborate-substituted lithium pyrazolide according to the general formula 1) as indicated below

wherein:

Each F2 is the same or independently selected from the group comprising linear or branched alkyl or cycloalkyl groups having 1 to 12 carbon atoms, linear or branched perfluorinated or partially fluorinated alkyl or cycloalkyl groups having 1 to 12 carbon atoms and / or perfluorinated or partially fluorinated phenyl,

as conducting salt in lithium-based electrochemical cells and

Energy storage devices.

5. Use according to claim 4, characterized in that R Fl and R F2 are each the same or independently selected from the group comprising linear or branched perfluorinated alkyl or cycloalkyl groups having 1 to 6 carbon atoms and / or pentafluorophenyl, preferably a linear perfluorinated alkyl group having 1 to 6 carbon atoms, preferably selected from the group comprising CF ₃ , C ₂ F ₅ , C ₃ F ₇ and / or C ₄ F ₉ .

6. Electrolyte for a lithium-based electrochemical cell or

An energy storage device comprising a trifluoroborate-substituted lithium pyrazolide according to the general formula (1) as given below

wherein: R Fl R ^J F2 is in each case the same or independently selected from the group comprising linear or branched alkyl or cycloalkyl groups having 1 to 12 carbon atoms, linear or branched perfluorinated or partially fluorinated alkyl or cycloalkyl groups having 1 to 12 Carbon atoms and / or perfluorinated or partially fluorinated phenyl.

7. An electrolyte according to claim 6, characterized in that R and R are each the same or independently selected from the group comprising linear or branched perfluorinated alkyl or cycloalkyl groups having 1 to 6 carbon atoms and / or pentafluorophenyl, preferably a linear perfluorinated alkyl group having 1 to 6 carbon atoms, preferably selected from the group comprising CF ₃ , C ₂ F ₅ , C ₃ F ₇ and / or C ₄ F ₉ .

8. An electrolyte according to claim 6 or 7, characterized in that concentration of the trifluoroborate-substituted lithium pyrazolide in the electrolyte in the range of> 0.5 mol / kg to <1.25 mol / kg, preferably in the range of> 0.75 mol / kg to <1 mol / kg, more preferably in the range of> 0.75 mol / kg to <0.85 mol / kg.

9. Lithium-based electrochemical cell or energy storage device, preferably lithium battery, lithium-ion battery, lithium-ion battery, lithium-polymer battery, lithium-ion capacitor and / or dual-ion cell, comprising an electrolyte according to one of claims 6 to 8.

10. A process for producing a trifluoroborate-substituted lithium pyrazolide, wherein a pyrazole represented by the general formula (2) as shown below:

wherein: R _, R are each the same or independently selected from the group consisting of linear or branched alkyl or cycloalkyl groups having 1 to 12 carbon atoms, linear or branched perfluorinated or partially fluorinated alkyl or cycloalkyl groups having 1 to 12 carbon atoms Atoms, and / or perfluorinated or partially fluorinated phenyl,

lithiated and then reacted with BF ₃ .