BICYCLIC TRIOL BORATE AND USE THEREOF IN AN ELECTROLYTE COMPOSITION IN AN ENERGY STORE

Abstract

A bicyclic triolborate of the general formula

##STR00001##

and its use in an electrolyte composition. The use of a bicyclic triolborate in an electrolyte composition in electrochemical supercapacitors, such as for example in double-layer capacitors in electric motors.

Claims

1. A bicyclic triolborate having the following structural formula ##STR00020## wherein R1 to R6 independently of each other are selected from hydrogen, hydroxy, nitro, halide group or substituted or unsubstituted hydroxyalkyl, alkyl, isoalkyl, alkenyl, aryl, heteroaryl, cycloalkyl, haloalkyl, alkoxy, alkoxycarbonyl, phenyl, naphthyl group; wherein X is selected from nitrogen, phosphorus and carbon, wherein the carbon may be substituted with hydrogen, nitro, halide group or substituted or unsubstituted hydroxyalkyl, alkyl, isoalkyl, alkenyl, aryl, heteroaryl, cycloalkyl, haloalkyl, alkoxy, alkoxycarbonyl, phenyl, naphthyl group; wherein Y is selected from hydrogen, hydroxy, cyano, nitro, halide group or substituted or unsubstituted hydroxyalkyl, alkyl, isoalkyl, alkenyl, aryl, heteroaryl, cycloalkyl, haloalkyl, alkoxy, alkoxycarbonyl, phenyl, naphthyl group; wherein Z.sup.+ is an ion of the general formula R′.sub.nA.sup.+ with n=1-4.

2. The triolborate according to claim 1, wherein R1 to R6 independently of each other are selected from the group comprising; an alkyl group with 1-6 carbon atoms, 1-5 carbon atoms, 1-4 carbon atoms, 1-3 carbon atoms, 1-2 carbon atoms or one carbon atom, and a haloalkyl group with 1-6 carbon atoms, 1-5 carbon atoms, 1-4 carbon atoms, 1-3 carbon atoms, 1-2 carbon atoms or one carbon atom.

3. The triolborate according to claim 1, wherein X is a carbon with a substituent selected from the group comprising; an alkyl group with 1-6 carbon atoms, 1-5 carbon atoms, 1-4 carbon atoms, 1-3 carbon atoms, 1-2 carbon atoms or one carbon atom, and a haloalkyl group with 1-6 carbon atoms, 1-5 carbon atoms, 1-4 carbon atoms, 1-3 carbon atoms, 1-2 carbon atoms or one carbon atom.

4. The triolborate according to claim 1, wherein Y is selected from the group comprising: an alkyl group with 1-6 carbon atoms, 1-5 carbon atoms, 1-4 carbon atoms, 1-3 carbon atoms, 1-2 carbon atoms or one carbon atom, and a haloalkyl group with 1-6 carbon atoms, 1-5 carbon atoms, 1-4 carbon atoms, 1-3 carbon atoms, 1-2 carbon atoms or one carbon atom.

5. The triolborate according to claim 1, wherein Y contains at least one fluorine atom.

6. The triolborate according to claim 1, wherein in the counterion Z.sup.+ A is selected from the group comprising nitrogen and phosphorus.

7. The triolborate according to claim 1, wherein in the counterion Z.sup.+ R′ is selected from the group comprising hydrogen, linear or branched alkyl groups or linear or branched haloalkyl groups, particularly preferably from linear alkyl groups or linear haloalkyl groups.

8. The triolborate according to claim 1, wherein the counterion Z.sup.+ is selected from the group comprising ammonium, tetraalkylammonium, cyclic ammonium, spiro ammonium, imidazolium, ##STR00021## with R1″=bridging cyclic group, R2″, R3″=two alkyl groups or one hydrogen and one alkyl group and ##STR00022## with R1″′, R2″′=bridging cyclic alkyl group.

9. An electrolyte composition for an energy storage facility comprising a bicyclic triolborate according to claim 8 and 0-75% by volume of one or more solvents.

10. The electrolyte composition according to claim 9, wherein the electrolyte solution is free of acetonitrile.

11. The electrolyte composition according to claim 10, wherein the melting temperature of the electrolyte composition is lower than 100° C.

12. A capacitor containing an electrolyte composition comprising a bicyclic triolborate.

13. The capacitor according to claim 12, wherein the electric strength of the capacitor is at least 2 V.

14. The capacitor according to claim 12, wherein the charge capacity of the capacitor is at least 10° F.

15. The capacitor according to claim 12, wherein the voltage window of the capacitor is in a range of 2 V to 4 V.

16. The capacitor according to claim 12, wherein the internal resistance of the capacitor is lower than 20 mΩ.

17. A use of a bicyclic triolborate in an electrolyte composition in an energy storage facility, in particularly a capacitor.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0062] FIG. 1 shows an X-ray powder diffractogram of structure (A). On the x-axis the angle of diffraction 2θ is shown in degree (°) and on the y-axis the intensity is shown in arbitrary units (a. u.).

[0063] FIG. 2 shows a unit cell of structure (A)*4 H.sub.2O.

[0064] FIG. 3 shows cyclic voltammetry diagrams of structure (D) in acetonitrile, wherein different scanning rates have been used. On the x-axis the voltage is shown in volt (V) and on the y-axis the strength of current is shown in 10.sup.−4 ampere (10.sup.−4 A).

DETAILED DESCRIPTION OF THE INVENTION

Examples

[0065] The present invention is illustrated by the following examples, wherein the invention is not limited thereto.

Synthesis of Bicyclic Triolborates According to the Present Invention

[0066] The bicyclic triolborates according to the present invention of the examples 1-5 which have the structural formulas (B), (C), (D), (F) and (G) were each synthesized by ion exchange reactions from the lithium triolborate salt of the structural formula (A) or the structural formula (F). These triolborates are shown in table 1.

TABLE-US-00001 TABLE 1 Exam- ple Name Structural formula Educt 1 lithium-1,4- dimethyl-2,6,7- trioxa-1- boratobicyclo- [2.2.2]-octane [00006] (A) 1 tetramethyl- ammonium-1,4- dimethyl-2,6,7- trioxa-1- boratobicyclo- [2.2.2]-octane [00007] (B) 2 tetraethyl- ammonium-1,4- dimethyl-2,6,7- trioxa-1- boratobicyclo- [2.2.2]-octane [00008] (C) 3 tetrabutyl- ammonium-1,4- dimethyl-2,6,7- trioxa-1- boratobicyclo- [2.2.2]-octane [00009] (D) 4 1-ethyl-3- methylimidazolium- 1,4-dimethyl-2,6,7- trioxa-1- boratobicyclo- [2.2.2]-octane [00010] (E) Educt 2 lithium-1-butyl-4- methyl-2,6,7- trioxa-1- boratobicyclo- [2.2.2]-octane [00011] (F) 5 tetraethyl- ammonium-1- butyl-4-methyl- 2,6,7-trioxa-1- boratobicyclo- [2.2.2]-octane [00012] (G)

##STR00013##

[0067] The substance having the structural formula (A) as starting substance for the ion exchange reactions was synthesized as described below. At −78° C., to a solution of 50 mmol of triisopropyl borate (a1) in 100 ml tetrahydrofuran 50 mmcl of 1.6 molar methyllithium solution (a2) were added. At first the reaction solution was stirred for 30 minutes at −78° C. and subsequently for further eight hours at room temperature. Thereafter 50 mmol of 1,1,1-tris(hydroxymethyl)ethane (a3) were added. The resulting mixture was heated to 60° C. for one hour. After the reaction was completed, the solution was given into one liter of water-free acetone, and the precipitate was filtered, washed with acetone and dried in high vacuum. 6.78 g (45 mmol) of the substance having the structural formula (A) were obtained.

1.2 Example 1

[0068] ##STR00014##

[0069] In example 1 the substance having the structural formula (B) was synthesized as described below. Under protective gas 10.32 mmol of lithium-1,4-dimethyl-2,6,7-trioxa-1-boratobicyclo-[2.2.2]-octane (b1) and 10.32 mmol of tetramethylammonium chloride (b2) were each dissolved in 10 ml water-free methanol. Subsequently, at 0° C. under protective gas and stirring both solutions were combined and stirred at room temperature for further two hours. After the reaction was completed, the reaction solution was concentrated to dryness. To the residue 20 ml water-free dichloromethane were added, and it was swirled. The supernatant was decanted, and subsequently it was concentrated. 1.05 g (4.84 mmol) of the substance having the structural formula (B) were obtained.

1.3 Example 2

[0070] ##STR00015##

[0071] In example 2, the substance having the structural formula (C) was synthesized as described below. Under protective gas 10.32 mmol of lithium-1,4-dimethyl-2,6,7-trioxa-1-boratobicyclo-[2.2.2]-octane (c1) and 10.32 mmol of tetraethylammonium chloride (c2) were each dissolved in 10 ml water-free methanol. Subsequently, at 0° C. under protective gas and stirring both solutions were combined and stirred at room temperature for further two hours. After the reaction was completed, the reaction solution was concentrated to dryness. To the residue 20 ml water-free dichloromethane were added, and it was swirled. The supernatant was decanted, and subsequently it was concentrated. 1.12 g (4.10 mmol) of the substance having the structural formula (C) were obtained.

1.4 Example 3

[0072] ##STR00016##

[0073] In example 3, the substance having the structural formula (D) was synthesized as described below. 10.34 mmol of lithium-1,4-dimethyl-2,6,7-trioxa-1-boratobicyclo-[2.2.2]-octane (d1) were dissolved in 10 ml water-free methanol. Subsequently, 13.34 mmol of tetrabutylammonium chloride, dissolved in 10 ml water-free methanol, (d2) were added at 0° C., and it was stirred for further two hours at room temperature. After the reaction was completed, the solution was extracted with dichloromethane, and the combined extracts were concentrated. 1.35 g (3.50 mmol) of the substance having the structural formula (D) were obtained.

1.5 Example 4

[0074] ##STR00017##

[0075] In example 4, the substance having the structural formula (E) was synthesized as described below. 4.98 mmol of lithium-1,4-dimethyl-2,6,7-trioxa-1-boratobicyclo-[2.2.2]-octane (el) were dissolved in 10 ml water-free methanol. Subsequently, 4.98 mmol of 1-ethyl-3-methylimidazolium chloride, dissolved in 10 ml water-free methanol, were added at 0° C., and it was stirred for further two hours at room temperature. After the reaction was completed, the reaction solution was concentrated to dryness. To the residue 20 ml water-free dichloromethane were added, and it was swirled. The supernatant was decanted, and subsequently it was concentrated. 0.39 g (1.53 mmol) of the substance having the structural formula (E) were obtained.

1.6 Educt 2

[0076] ##STR00018##

[0077] As further starting substance for ion exchange reactions, the substance having the structural formula (F) was used which has been prepared as described below. At −78° C., to a solution of 50 mmol of triisopropyl borate (f1) in 100 ml tetrahydrofuran 50 mmol of 1.6 molar butyllithium solution (f2) were added. At first the reaction solution was stirred for 30 minutes at −78° C. and subsequently for further eight hours at room temperature. Thereafter 50 mmol of 1,1,1-tris(hydroxymethyl)ethane (f3) were added. The resulting mixture was heated to 60° C. for one hour. After the reaction was completed, the solution was given into one liter of water-free acetone, and the precipitate was filtered, washed with acetone and dried in high vacuum. 9.2 g (48 mmol) of the substance having the structural formula (F) were obtained.

1.7 Example 5

[0078] ##STR00019##

[0079] In example 5, the substance having the structural formula (G) was synthesized as described below. At 0° C., to a solution of 10.81 mmol of lithium-1-butyl-4-methyl-2,6,7-trioxa-1-boratobicyclo-[2.2.2]-octane (g1) in 5 ml methanol a solution of 10.81 mmol of tetraethylammonium chloride (g2) in 5 ml methanol was added. The solution was stirred for further two hours at room temperature. Subsequently, it was extracted with dichloromethane. The combined extracts were concentrated in a rotary evaporator and subsequently dried in fine vacuum. 1 g (3.89 mmol) of the substance having the structural formula (G) was obtained.

[0080] Nuclear Magnetic Resonance Spectroscopy

[0081] The lithium triolborate salts as educts and the substances of the examples 1 to 5 were characterized by means of nuclear magnetic resonance spectroscopy. .sup.1H-NMR, .sup.13C-NMR and .sup.11B-NMR measurements at 300 K and 500 MHz were conducted with a DRX500 spectrometer with deuterated dimethyl sulfoxide. Table 2 shows the peaks of the substances (A), (B), (C), (D), (E), (F) and (G) which were measured in the obtained NMR spectra.

TABLE-US-00002 TABLE 2 NMR Peaks [ppm] Peaks [ppm] Peaks [ppm] Peaks [ppm] Peaks [ppm] Peaks [ppm] Peaks [ppm] measur. (A) (B) (C) (D) (E) (F) (G) .sup.1H-NMR −0.72 (s, 3H); −0.75 (s, 3H); −0.75 (s, 3H); −0.78 (s, 3H); −0.62 (s, 3H); −0.22 (t, 2H); 1.17 (tt 3H); 0.38 (s, 3H); 3.10 (s, 3H); 0.38 (s, 3H); 0.37 (s, 3H); 0.46 (s, 3H); 0.37 (s, 3H); 3.21 (q, 2H); 3.42 (s, 6H) 0.38 (s, 3H); 1.17 (tt, 3H); 0.94 (t, 12H); 1.46 (t, 3H); 0.76 (t, 2H); −0.20 (t, 2H); 3.42 (s, 6H) 3.22 (q, 2H); 1.32 (m, 8H); 3.48 (s, 3H); 0.92-1.05 (m, 3H); 0.37 (s, 3H); 3.41 (s, 6H) 1.57 (m, 8H); 3.91 (s, 6H); 1.06-1.17 (m, 2H); 0.76 (t, 2H); 3.16 (t, 8H); 4.27 (q, 2H); 3.40 (s, 6H) 0.99-1.06 (m, 3H); 3.41 (s, 6H) 7.82 (dd, 1H); 1.07-1.13 (m, 2H); 7.91 (dd, 1H); 3.43 (s, 6H) 9.53 (s, 1H) .sup.13C-NMR 5.14; 16.30; 54.34; 16.29; 7.09; 51.43; 13.45; 19.19; 15.17; 16.31; 14.45; 16.38; 7.07; 51.44; 33.88; 73.25 33.97; 73.23 4.76; 16.23; 23.07; 57.55; 34.11; 44.01; 26.53; 28.55; 14.42; 16.45; 33.88; 73.13 16.34; 48.40; 54.97; 63.89; 73.29 26.45; 28.46; 73.39 72.52; 121.97; 72.96 123.54; 136.58 .sup.11B-NMR 3.11 2.32 5.60 5.42 3.11 5.81 7.25

[0082] X-Ray Powder Diffractometry

[0083] Substance (A) was characterized by X-ray powder diffractometry. The measurement was conducted with copper radiation (1.55060 Å), germanium (111) monochromator and scintillation counter from 5.005° to 67,145°. The obtained diffractogram is shown in FIG. 1. FIG. 1 shows reflexes at small angles. This indicates that substance (A) has a large unit cell.

[0084] Structural Single Crystal X-Ray Analysis

[0085] Substance (A) was characterized by structural single crystal X-ray analysis. The measurement was conducted with molybdenum radiation (0.71073 Å) at 155 K. The crystals selected for this contained additional water of crystallization. The obtained unit cell is shown in FIG. 2. For a better overview, here, the hydrogen atoms are not shown.

[0086] In FIG. 2, carbon atoms are shown in black, oxygen atoms are shown in white, boron atoms are shown checkered and lithium ions are shown striped. FIG. 2 shows that the cations of substance (A) in the crystal structure are surrounded by water molecules in a tetrahedral manner. The anions of substance (A) are arranged in layers which are stacked along the b-axis of the unit cell (FIG. 2).

[0087] Cyclic Voltammetry Measurement

[0088] In example 3, substance (D) was characterized by cyclic voltammetry measurement. For the measurement a glassy carbon electrode was used as working electrode, a platinum electrode was used as counter electrode and a silver/silver chloride electrode was used as reference electrode. One cycle each with a scanning rate of 10 mV/s, 20 mV/s and 50 mV/s, and 50 cycles with a scanning rate of 20 mV/s were conducted from −1 to 2 V and −2 to 2 V with a solution of 50 mg of substance (D) in 100 ml acetonitrile under constant stirring. Substance (D) exhibits a high electrochemical stability, because the cycles at different scanning rates in the voltage range of between −2 and 2 V are closing.