Battery

Abstract

The present invention relates to a battery that includes at least one electrochemical cell. The at least one electrochemical cell includes a first electrode, a second electrode, a first electroactive material, a second electroactive material, and an electrolyte which is in contact with both electrodes, and at least one of the first electroactive material and the second electroactive material includes a radialene compound. Also provided is an electroactive material as well as a radialene compound.

Claims

1. A battery comprising at least one electrochemical cell, the at least one electrochemical cell comprising a first electrode, a second electrode, a first electroactive material, a second electroactive material, and an electrolyte, wherein the electrolyte is in contact with both electrodes, and at least one of the first electroactive material or the second electroactive material comprises a radialene compound at an amount of at least 50% by weight, based on the weight of the first electroactive material or the second electroactive material, respectively, wherein the radialene compound comprises a carbocyclic core substituted with one or more groups independently selected from imino or methylidene, wherein the imino and methylidene groups are substituted with one or more electron withdrawing substituents, wherein the one or more electron withdrawing substituents are cyano groups.

2. The battery according to claim 1, wherein the first electroactive material comprises the radialene compound, and is disposed in a first compartment of the electrochemical cell, the first compartment comprising the first electrode, which is electrically connected with the positive pole of the battery.

3. The battery according to claim 1, wherein the radialene compound has the general formula (I): ##STR00009## wherein Z.sup.1, Z.sup.2 and Z.sup.3 are independently selected from dicyanomethylidene, or a cyanimino group, x is an integer selected from 1 or 2, y is an integer selected from 0, 1 or 2, and the dashed lines represent the following when y is 0, 1, or 2 i) when y is 0, 6 electrons delocalized over 6 bonds if x is 1, and 8 electrons delocalized over 8 bonds if x is 2, ii) when y is 1, 7 electrons delocalized over 6 bonds if x is 1, and 9 electrons delocalized over 8 bonds if x is 2, and iii) when y is 2, 8 electrons delocalized over 6 bonds if x is 1, and 10 electrons delocalized over 8 bonds if x is 2.

4. The battery according to claim 3, wherein at least one of Z.sup.1 and Z.sup.2, and at least one Z.sup.3 is dicyanomethylidene.

5. The battery according to claim 1, wherein the electrolyte comprises alkali metal cations.

6. The battery according to claim 1, wherein the first electroactive material in its reduced state comprises alkali metal cations.

7. The battery according to claim 1, wherein the second electroactive material in its reduced state comprises an alkali metal.

8. The battery according to claim 6, wherein the alkali metal cations are lithium cations.

9. The battery according to claim 7, wherein the alkali metal is Li.

10. An electroactive material comprising a radialene compound, wherein the electroactive material is solid or gel-like.

11. A compound having formula (II): ##STR00010## wherein Z.sup.1, Z.sup.2, and Z.sup.3 are independently selected from dicyanomethylidene or a cyanimino group, x is an integer selected from 1 or 2, the dashed lines represent 8 electrons delocalized over 6 bonds if x is 1, and 10 electrons delocalized over 8 bonds if x is 2, and excluding a compound of formula (II) wherein [i] x is 1, and [ii] Z.sup.1, Z.sup.2, and Z.sup.3 are dicyanomethylidene.

12. The compound according to claim 11, wherein at least one of Z.sup.1 and Z.sup.2, and at least one Z.sup.3 is dicyanomethylidene.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a cyclic voltammogram of 2,2,2-(cyclopropane-1,2,3-triylidene)trimalononitrile dilithium salt (1) in an electrolyte consisting of 0.1M LiPF.sub.6 in the mixture ethylene carbonate (EC):diethyl carbonate (DEC) having volume ratio v/v=1/2

(2) FIG. 2 shows first charge/discharge curve vs. lithium at different charging rates of 2,2,2-(cyclopropane-1,2,3-triylidene)trimalononitrile bis lithium salt (1) as cathode, lithium metal as anode, and 1M LiN(CF.sub.3SO.sub.2) in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide as electrolyte. FIG. 2A shows charge/discharge at C/10 (19.3 mA/g). FIG. 2B shows charge/discharge at C/2 (93 mA/g).

(3) FIG. 3 shows the variation of discharge capacity with the number of cycles of 2,2,2-(cyclopropane-1,2,3-triylidene)trimalononitrile bis lithium salt (1) as cathode, lithium metal as anode, in 1M LiN(CF.sub.3SO.sub.2) in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide electrolyte

(4) FIG. 4 shows a cyclic voltammogram of 2,2-(2,4-dioxocyclobutane-1,3-diylidene)dimalononitrile bis lithium salt (2) in an electrolyte consisting of mixed solvent EC:DEC (v/v=1/2) with 0.1M LiPF.sub.6 at scan rate of 50 mV/s at room temperature.

(5) FIGS. 5A, 5B, show the first charge/discharge curve vs. lithium at different charging rates of an electrochemical cell having 2,2-(2,4-dioxocyclobutane-1,3-diylidene)dimalononitrile bis lithium salt (2) as cathode, lithium metal as anode, and 1M LiN(CF.sub.3SO.sub.2) in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide as electrolyte. FIG. 5A shows charge/discharge at C/10 (8.2 mA/g). FIG. 5B shows charge/discharge at C/2 (35 mA/g).

(6) FIG. 6 shows the variation of discharge capacity with the number of cycles of 2,2-(2,4-dioxocyclobutane-1,3-diylidene)dimalononitrile bis lithium salt (2) as cathode, lithium metal as anode, and 1M LiN(CF.sub.3SO.sub.2) as cathode, lithium metal as anode, in 1M LiN(CF.sub.3SO.sub.2) in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide electrolyte

EXAMPLES

Example 1

Dilithium salt of (3-(dicyanomethylene)cycloprop-1-ene-1,2-diyl)bis(dicyanomethanide) (1)

Step 1, Tetrabutylammonium (TBA) salt of (3-(dicyanomethylene)cycloprop-1-ene-1,2-diyl)bis(dicyanomethanide) (Preparation is described in U.S. Pat. No. 3,963,769)

(7) Under argon, sodium hydride (5.6 g, approx. 60 wt. % suspension in mineral oil, 7.0 eq) was washed with 330 mL hexanes, suspended in 130 mL anhydrous glyme and then cooled down to 4 C. with an ice/water bath. In 15 min, redistilled malononitrile (4.22 g, 3.2 eq.) in 15 mL anhydrous glyme was added dropwise (gas evolution). The beige slurry was stirred 1 h at 0 C., before tetrachlorocyclopropene (2.45 mL, 1.0 eq) in anhydrous glyme (7.0 mL) is added slowly (during ca. 15 min, gas evolution) to the reaction mixture. The brown slurry was stirred 1 h at 0 C., then let warm up slowly to the room temperature (rt). Dropwise addition of 5 mL distilled water to quench and then diluting the reaction mixture with 70 mL distilled water was followed by addition of aqueous tetrabutylammonium bromide (TBABr, 14.1 g, 2.2 eq. previously dissolved in 15 mL distilled water). The resulting slurry was stirred for 2 h and the formed precipitate was filtered. After thoroughly washing with water (530 mL), the brown precipitate was dried in vacuo or at air overnight. The solid was then dissolved in 200 mL acetonitrile (AN) and re-precipitated by addition 600 mL ethyl acetate (EA). Precipitation can be repeated once more to get a colorless solid.

(8) Yield: 12.1 g (85%)

(9) Analytics:

(10) ESI-MS (in 100% AN) neg: 470, 228.

(11) IR (solid, measured in the attenuated total reflectance (ATR) arrangement): 2962 m, 2936 m, 2865 m, 2182 s, 2163 s, 1412 s cm.sup.1.

(12) Step 2, Lithium salt of (3-(dicyanomethylene)cycloprop-1-ene-1,2-diyl)bis(dicyanomethanide), Li.sub.2C.sub.12N.sub.6 (1):

(13) Tetrabutylammonium (3-(dicyanomethylene)cycloprop-1-ene-1,2-diyl)bis(dicyano methanide) (12.0 g, 17.0 mmol) was dissolved in 230 mL AN, a solution 11.4 g lithium iodide (5.0 eq.) in 50 mL AN was added and the reaction mixture was heated at 80 C. under inert atmosphere for 20 h. The reaction mixture was cooled down to approx. 50 C. and the pale yellow precipitate was filtered under inert atmosphere. Washing with 315 mL AN and drying in vacuo afforded 2.65 g (64%) pale yellow solid.

(14) Analytics:

(15) ESI-MS (in 100% AN) neg: 228, 114 m/z.

(16) IR (solid, ATR): 2223 s, 2195 s, 2170 s, 1638 m, 1425 s cm.sup.1.

Example 2

Lithium Salt of 2,2-(2,4-dioxo-1,3-cyclobutanediyl)bis-propanedinitrile (2) Step 1, Sodium Salt of 2,2-(2,4-dioxo-1,3-cyclobutanediyl)bis-propanedinitrile

(17) 0.94 g Sodium was dissolved in 100 mL dry ethanol and stirred over night. 3.1 g starting betaine 1,3-bis(dimethylamino)-2,4-dihydroxy-cyclobutanediylium (18.5 mmol) was added and the mixture stirred for 15 min, followed by addition of 2.44 g malonitrile. The mixture was refluxed for 3.5 h. After cooling to rt, the solid was filtered off and washed with ethanol. Drying was done in vacuum at 50 C./10 mbar over night.

(18) Yield: 4.9 g (79%)

(19) Analytics:

(20) ESI-MS (in 100% AN) neg: 207.

Step 2, Tetrabutyl ammonium salt of 2,2-(2,4-dioxo-1,3-cyclobutanediyl)bis-propanedinitrile

(21) The sodium salt of 2,2-(2,4-dioxo-1,3-cyclobutanediyl)bis-propanedinitrile (2.9 g) was suspended in 60 mL water and 7.3 g TBABr dissolved in 60 mL chloroform were added at rt and stirred for 2 h. The mixture was poured into a separator funnel and three phases were obtained. The solid was filtered off, washed with small portions water and chloroform, and dried on a clay plate, then in vacuum at 50 C./10 mbar over night to give 3.9 g yellow powder. A cca 1.4 second crop of the product was obtained after stirring the filtrate for 1 week, filtration, washing with small portions chloroform and drying in vacuum at 50 C./10 mbar over night.

(22) Yield: 3.9 g (50%, the first crop only)

(23) Analytics:

(24) ESI-MS (in 100% AN) neg: 208, 450.

(25) IR (solid, ATR): 2961 m, 2874 m, 2176 s, 2155 s, 1580 s, 1369 cm.sup.1.

Step 3, Lithium Salt of 2,2-(2,4-dioxo-1,3-cyclobutanediyl)bis-propanedinitrile (2)

(26) In a glove box, TBA salt of 2,2-(2,4-dioxo-1,3-cyclobutanediyl)bis-propanedinitrile (0.333 g/0.48 mmol) and LiI (0.300 g/2.24 mmol) were placed in a flask and 7.5 mL acetonitrile were added. A yellow precipitate occurred immediately. The mixture was allowed to stir over night. The precipitate was filtered off, washed with AN and dried in vacuum at 50 C./10 mbar over night to give 0.12 g (82%) yellow solid.

(27) Analytics:

(28) ESI-MS (100% AN) neg: 208.

(29) IR (solid): 2196 s, 1594 m, 1543 s, 1383 s, 1364 s cm.sup.1.

Example 3

CV Measurement

(30) Cyclic voltammetry (CV) was performed using a three electrode glass cell using Potentiostat/Galvanostat PGSTAT 30. Pt disc d=1 mm was used as working electrode, Pt wire as counter electrode and Ag/AgCl as reference electrode, and 0.1M LiPF.sub.6 in ethylene carbonate:diethyl carbonate EC:DEC (v/v=1/2) was used as electrolyte. The CV measurements were done at the scan rate 50 mV/s and rt. CV data are shown in FIG. 1 and FIG. 4.

Example 4

Cathode Electrode Preparation for Battery Test

(31) The obtained materials of the present invention were eventually mixed with carbon and ethylene propylene diene monomer (EPDM) in a weight ratio 50:40:10 in cyclohexane to form a slurry. The obtained slurry was coated on aluminum foil using Doctor Blade and was dried to make the cathode electrode.

Example 5

Charging/Discharging Tests

(32) The charging/discharging tests were performed using a Swagelock-type cell assembled under argon. The testing cells were prepared by sandwiching the separator filled with electrolyte between lithium foil 1.2 mm and the prepared composite cathode electrode (Example 3). Glass fiber (GF/D) from Whatman was used as a separator. Lithium foil was used as counter and reference electrodes. A solution of 1 M LiN(CF.sub.3SO.sub.2).sub.2 in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide was used as electrolyte. Charge/discharge cycling was carried out between 2.8 and 4.2 V using a BaSyTec cell test system (BaSyTec GmbH). The results of charging discharging test are shown in FIGS. 2A and B, FIG. 3, FIGS. 5A and B, and FIG. 6.

(33) The cyclic voltammogram shown in FIG. 1 recorded for 2,2,2-(cyclopropane-1,2,3-triylidene)trimalononitrile bis lithium salt (1) demonstrates reversible redox system featuring the transfer of two electrons, as indicated by two oxidation peaks at the anodic scan and two reduction peaks during cathode scan. From the CV data, it is clear that Li.sub.2C.sub.12N.sub.6 (1) shows a fully reversible redox behaviour, an important condition for applicability of this compound as active material in a rechargeable battery.

(34) FIGS. 2A and 2B show the first charge/discharge curves of (I) as cathode active material and lithium as anode at C/10 and C/2 rates respectively. In both curves at charging state one can see two plateaus at around 3.55 and 4 V corresponding to the oxidation of Li.sub.2C.sub.12N.sub.6 under release of two lithium cations and formation of C.sub.12N.sub.6, at the discharging curve corresponding to the reduction of C.sub.12N.sub.6 to Li.sub.2C.sub.12N.sub.6, two other plateaus are observed at 3.75 and 3.2 V.

(35) The secondary battery cell using (1) as cathode material provides a high discharging capacity of 193 mAh/g at C/10 and 186 mAh/g at C/2.

(36) It is clear from the electrochemical tests that the use of compound (1) in the cathode provides a rechargeable lithium ion battery with a higher charging and discharging voltage. The voltage of the electrochemical cell using Li.sub.2C.sub.12N.sub.6 as cathode and lithium as anode after charging was 3.8V and no self discharge was observed.

(37) FIG. 3 illustrates the discharge capacity vs. cycle number profile of Li.sub.2C.sub.12N.sub.6 (I) as cathode at C/10. Discharge capacity of 148 mAh/g remains after 12 cycles.

[4]Radialene (2) (Example 2,2-(2,4-dioxocyclobutane-1,3-diylidene)dimalononitrile bis lithium Salt) as Cathode Material

(38) Cyclic voltammetry results presented in FIG. 4, show fully reversible behaviour.

(39) The first charge/discharge curves of the Li.sub.2C.sub.10N.sub.4O.sub.2 (2) as cathode active material and lithium as anode at C/10 and C/2 rates are presented in FIGS. 5A and 5B respectively. In both curves, during charging of the electrochemical cell, two plateaus are identified at around 3.6 and 4V corresponding to the oxidation of Li.sub.2C.sub.12N.sub.6 (release of two lithium cations and formation of C.sub.12N.sub.6), at the discharging curve two other plateaus are observed at 3.87 and 3.2 V. The electrochemical cell using (2) as cathode material provides the discharging capacity 82 mAh/g at C/10 and 70 mAh/g at C/2.

(40) The variation of discharge capacity with the number of cycles for the battery cell using (2) as cathode active material at C/10 is presented in FIG. 6. A 67% retention of the initial capacity was observed after 12 cycles.

(41) The features disclosed in the foregoing description, in the claims and in the accompanying drawings may, both separately or in any combination be material for realizing the invention in diverse forms thereof.