COMPOSITION

Abstract

Use of a compound of Formula 1 in a nonaqueous battery electrolyte formulation (1) wherein each R.sup.1 to R.sup.4 is selected from the group consisting of F, Cl, H, CF.sub.3, and C.sub.1 to C.sub.6 alkyl which may be at least partially fluorinated, wherein at least one of R.sup.1 to R.sup.4 is or comprises F.

##STR00001##

Claims

1. A nonaqueous battery electrolyte formulation, comprising a compound of Formula 1: ##STR00008## wherein each of R.sup.1 to R.sup.4 is independently selected from the group consisting of F, Cl, H, CF.sub.3, and C.sub.1 to C.sub.6 alkyl which is optionally at least partially fluorinated; and wherein at least one of R.sup.1 to R.sup.4 is or comprises F.

2. A battery, comprising the formulation according to claim 1.

3. The formulation according to claim 1, further comprising a metal electrolyte salt, present in an amount of from 0.1 to 20 wt % relative to a total mass of the formulation, wherein the metal salt is a salt of lithium, sodium, magnesium, calcium, lead, zinc, or nickel.

4. (canceled)

5. The formulation according to claim 3, wherein the metal salt is a salt of lithium selected from the group consisting of lithium hexafluorophosphate (LiPF.sub.6), lithium hexafluoroarsenate monohydrate (LiAsF.sub.6.H.sub.2O), lithium perchlorate (LiClO.sub.4), lithium tetrafluoroborate (LiBF.sub.4), lithium triflate (LiSO.sub.3CF.sub.3), lithium bis(fluorosulfonyl)imide (Li(FSO.sub.2).sub.2N), and lithium bis(trifluoromethanesulfonyl)imide (Li(CF.sub.3SO.sub.2).sub.2N).

6. The formulation according to claim 1, further comprising an additional solvent in an amount of from 0.1 wt % to 99.9 wt % of a liquid component of the formulation, wherein the additional solvent is selected from the group consisting of fluoroethylene carbonate (FEC), propylene carbonate (PC), ethylene carbonate (EC), and ethyl methyl carbonate (EMC).

7-8. (canceled)

9. The formulation according to claim 1, further comprising a metal ion, optionally in combination with a solvent.

10-15. (canceled)

16. A method of reducing the flammability of a battery and/or a battery electrolyte, the method comprising adding to the battery and/or the battery electrolyte the formulation according to claim 1.

17. A method of powering an article comprising a battery, the method comprising adding to the battery a battery electrolyte formulation comprising a compound of Formula 1: ##STR00009## wherein each of R.sup.1 to R.sup.4 is independently selected from the group consisting of F, Cl, H, CF.sub.3, and C.sub.1 to C.sub.6 alkyl which is optionally at least partially fluorinated; and wherein at least one of R.sup.1 to R.sup.4 is or comprises F.

18. A method of retrofitting a battery electrolyte, the method comprising (a) at least partially replacing the battery electrolyte with the formulation according to claim 1; and/or (b) supplementing the battery electrolyte with the formulation.

19. A method of preparing a formulation containing the compound of according to claim 1, the method comprising by reacting a compound of Formula 2 ##STR00010## with an oxidizing agent so as to produce the compound.

20. A method of preparing the formulation according to claim 5, the method comprising mixing the compound of Formula 1 with dimethyl carbonate (DMC), fluoroethylene carbonate (FEC), propylene carbonate (PC), and ethylene carbonate (EC), or methyl ethyl carbonate (EMC) and with the salt of lithium so as to produce the formulation.

21. The method according to claim 17, wherein a capacity of the battery and/or a charge transfer within the battery is improved relative to a battery without the formulation.

22. The method according to claim 17, wherein the formulation further comprises a metal electrolyte salt, present in an amount of from 0.1 to 20 wt % relative to a total mass of the formulation, wherein the metal salt is a salt of lithium, sodium, magnesium, calcium, lead, zinc, or nickel.

23. (canceled)

24. The method according to claim 22, wherein the metal salt is a salt of lithium selected from the group consisting of lithium hexafluorophosphate (LiPF.sub.6), lithium hexafluoroarsenate monohydrate (LiAsF.sub.6.H.sub.2O), lithium perchlorate (LiClO.sub.4), lithium tetrafluoroborate (LiBF.sub.4), lithium triflate (LiSO.sub.3CF.sub.3), lithium bis(fluorosulfonyl)imide (Li(FSO.sub.2).sub.2N), and lithium bis(trifluoromethanesulfonyl)imide (Li(CF.sub.3SP.sub.2).sub.2N).

25. The method according to claim 17, wherein the formulation further comprises an additional solvent in an amount of from 0.1 wt to 99.9 wt % of a liquid component of the formulation, wherein the additional solvent is selected from the group consisting of dimethyl carbonate (DMC), fluoroethylene carbonate (FEC), propylene carbonate (PC), ethylene carbonate (EC), and methyl ethyl carbonate (EMC).

26. (canceled)

27. A nonaqueous battery electrolyte formulation, comprising a compound of Formula 1: ##STR00011## wherein R.sup.1 is H; R.sup.2 is CF.sub.3; and each of R.sup.3 and R.sup.4 is independently F or CF.sub.3.

28. A battery, comprising the formulation according to claim 27.

29. The formulation according to claim 27, further comprising a metal electrolyte salt, present in an amount of from 0.1 to 20 wt % relative to a total mass of the formulation, wherein the metal salt is a salt of lithium, sodium, magnesium, calcium, lead, zinc, or nickel.

30. The formulation according to claim 29, wherein the metal salt is a salt of lithium selected from the group consisting of lithium hexafluorophosphate (LiPF.sub.6), lithium hexafluoroarsenate monohydrate (LiAsF.sub.6.H.sub.2O), lithium perchlorate (LiClO.sub.4), lithium tetrafluoroborate (LiBF.sub.4), lithium triflate (LiSO.sub.3CF.sub.3), lithium bis(fluorosulfonyl)imide (Li(FSO.sub.2).sub.2N), and lithium bis(trifluoromethanesulfonyl)imide (Li(CF.sub.3SO.sub.2).sub.2N).

31. The formulation according to claim 27, further comprising an additional solvent in an amount of from 0.1 wt % to 99.9 wt % of a liquid component of the formulation, wherein the additional solvent is selected from the group consisting of fluoroethylene carbonate (FEC), propylene carbonate (PC), ethylene carbonate (EC), and methyl ethyl carbonate (EMC).

Description

EXAMPLE 1

Typical Procedure for Epoxidation of Fluoroalkenes

[0079] A one litre round bottomed flask was equipped with a chilled condenser, magnetic stirrer bar, thermometer and dry ice trap.

[0080] The flask was charged with NaOCl (500 mL, 6-14% active Cl), Aliquat 336 (5 mL, 0.1 mol) and Xylenes (150 mL, 1.23 mol). This mixture was stirred at 600 rpm and allowed to cool to around 5? C. at which point Z-1,3,3,3-Tetrafluoropropene (50 g, 0.44 mol) was added dropwise over the course of 20 minutes. The reaction mixture was stirred for twenty-four hours whilst gradually warming to room temperature. After twenty-four hours the mixture was transferred to a separating funnel and allowed to separate. The aqueous layer was discarded, and the organic layer was dried over anhydrous sodium sulphate and filtered to remove the spent desiccant.

[0081] The product was recovered from the xylene solvent by distillation.

[0082] Several batches of material were prepared. Each was first concentrated by performing a crude single stage distillation prior to combining them for further purification by fractional distillation using a vacuum jacketed distillation column (50 cm*2 cm) equipped with a reflux divider and packed with Pro-pak 0.16 square inch 316 stainless steel distillation packing.

[0083] The reboiler was charged with a mixture comprising crude Z-1,3,3,3-tetrafluoropropene epoxide in xylene (251 g). The mixture was brought to reflux and the system allowed to equilibrate before the product was collected in 9 fractions. Each fraction was analysed by GC-MS. Fractions 1-4 and 9 were combined to give 60.8 g of a product comprising 81.8% of Z-1,3,3,3-tetrafluoropropene epoxide. Fractions 5-8 were combined to give 63.7 g of a product comprising 98.7% of Z-1,3,3,3-tetrafluoropropene epoxide:

##STR00005##

[0084] Z-1,3,3,3-tetrafluoropropene epoxide ((2R,3R)-2-Fluoro-3-(trifludiromethyl)oxirane): Boiling point 54-55? C.; MS m/z 130, 111, 82, 80, 69, 63, 60, 51, 47, 45, 33; .sup.19F NMR (56 MHz) ? ?70.73 (ddd, J 13.0, 5.0, 2.0 Hz, 3F), ?165.27 to ?168.36 (m, 1F).

Flammability and Safety Testing

Flash Point

[0085] Flashpoints were determined using a Miniflash FLP/H device from Grabner Instruments following the ASTM D6450 standard method:

TABLE-US-00001 Concentration (% wt) in standard electrolyte 1 M LiPF.sub.6 in (30% Ethylene carbonate & 70% ethyl methyl carbonate) 0 2 5 10 30 100 Component Flashpoint (? C.) [00006] 32 ? 2 32 ? 2 28 ? 1 30 ? 1 26 ? 2 Not Detected (MEXI-3)

Self-Extinguishing Time

[0086] Self-extinguishing time was measured with a custom-built device that contained an automatically controlled stopwatch connected to an ultraviolet light detector: [0087] The electrolyte to be examined (500 ?L) was applied to a Whatman GF/D (?=24 mm) glass microfiber filter [0088] The ignition source was transferred under the sample and held in this its position for a preset time (1, 5 or 10 seconds) to ignite the sample. Ignition and burning of the sample were detected using a UV light detector. [0089] Evaluation is carried out by plotting the burning time/weight of electrolyte [s g.sup.?1] over ignition time [s] and extrapolation by linear regression line to ignition time=0 s [0090] Self-extinguishing time (s.Math.g.sup.?1) is the time that is needed until the sample stops burning once inflamed

TABLE-US-00002 Concentration (% wt) in standard electrolyte 1 M LiPF.sub.6 in (30% Ethylene carbonate & 70% ethyl methyl carbonate) 0 2 5 10 30 100 Component Self-extinguishing time (s.g.sup.?1) [00007] 39 ? 2 25 ? 2 28 ? 2 28 ? 2 25 ? 2 N.D.* (MEXI-3) *compund took more than 10 seconds to ignite

[0091] These measurements demonstrate that the compound MEXI-3 has flame retarding properties.

Electrochemical Testing

Drying

[0092] Before testing MEXI-3 was dried by treatment with a pre-activated type 4A molecular sieve to less than 10 ppm water.

Electrolyte Formulation

[0093] Electrolyte preparation and storage was carried out in an argon filled glove box (H.sub.2O and O.sub.2<0.1 ppm). The base electrolyte was 1M LiPF.sub.6 in ethylene carbonate:ethyl methyl carbonate (30:70 wt. %) with MEXI-3 additive at concentrations of 2, 5, 10 and 30 wt. %.

Cell Chemistry and Construction

[0094] The performance of each electrolyte formulation was tested in multi-layer pouch cells over 50 cycles (2 cells per electrolyte):

[0095] Chemistry 1: Lithium-Nickel-Cobalt-Manganese-Oxide (NCM622) positive electrode and artificial graphite (specific capacity: 350 mAh g.sup.?1) negative electrode. The area capacity of NMC622 and graphite amounted to 3.5 mAh cm.sup.?2 and 4.0 mAh cm.sup.?2, respectively. The N/P ratio amounted to 115%.

[0096] Chemistry 2: Lithium-Nickel-Cobalt-Manganese-Oxide (NCM622) positive electrode and SiO.sub.x/graphite (specific capacity: 550 mAh g.sup.?1) negative electrode. The area capacity of NMC622 and SiO.sub.x/graphite amount to 3.5 mAh/cm.sup.?2 and 4.0 mAh cm.sup.?2, respectively. The N/P ratio amounted to 115%

[0097] The test pouch cells had the following characteristics: [0098] Nominal capacity 240 mAh+/?2% [0099] Standard deviations: [0100] Capacity: ?0.6 mAh [0101] Coulombic Efficiency (CE) 1.sup.st cycle: ?0.13% [0102] Coulombic Efficiency (CE) subsequent cycles: ?0.1% [0103] Positive electrode: NMC-622 [0104] Active material content: 96.4% [0105] Mass loading: 16.7 mg cm.sup.?2 [0106] Negative electrode: Artificial Graphite [0107] Active material content: 94.8% [0108] Mass loading: 10 mg cm.sup.?2 [0109] Separator: PE(16 ?m)+4 ?m Al.sub.2O.sub.3 [0110] Balanced at cut-off voltage of 4.2 V [0111] Negative electrode: Artificial graphite+SiO [0112] Active material content: 94.6% [0113] Mass loading: 6.28 mg cm.sup.?2 [0114] Separator: PE(16 ?m)+4 ?m Al.sub.2O.sub.3 [0115] Balanced at cut-off voltage of 4.2 V

[0116] After assembly the following formation protocol was used: [0117] 1. Step charge to 1.5 V followed by 5 h rest step (wetting step @ 40? C.) [0118] 2. CCCV (C/10, 3.7 V (I.sub.limit: 1 h)) (preformation step) [0119] 3. Rest step (6 h) [0120] 4. CCCV (C/10, 4.2 V (I.sub.limit: 0.05 C)) rest step (20 min) [0121] 5. CC discharge (C/10, 3.8 V), (degassing of the cell) [0122] 6. CC discharge (C/10, 2.8 V)

[0123] Following this formation step, the cells were tested as follows: [0124] Rest step (1.5 V, 5 h), CCCV (C/10, 3.7 V (1 h)) [0125] Rest step (6 h), CCCV (C/10, 4.2 V (I.sub.limit: 0.05 C)) [0126] Rest step (20 min), CC discharge (C/10, 3.8 V) [0127] Degassing step [0128] Discharge (C/10, 2.8 V), rest step (5 h) [0129] CCCV (C/3, 4.2 V (I.sub.limit: 0.05 C)), rest step (20 min) [0130] CC discharge (C/3, 2.8 V) [0131] 50 cycles or until 50% SOH is reached at 40? C.: [0132] CCCV (C/3, 4.2 V (I.sub.limit: 0.02 C)), rest step (20 min) [0133] CC discharge (C/3, 3.0 V), rest step (20 min)

Test Results

[0134]

TABLE-US-00003 TABLE 1 Electrochemical performance of MEXI-3 - Cell Chemistry 1 Base electrolyte + Base electrolyte + Base electrolyte + Base electrolyte + Base electrolyte 2 wt. % MEXI-3 5 wt. % MEXI-3 10 wt. % MEXI-3 30 wt. % MEXI-3 Discharge Coulombic Discharge Coulombic Discharge Coulombic Discharge Coulombic Discharge Coulombic Cycle capacity efficiency capacity efficiency capacity efficiency capacity efficiency capacity efficiency No. (mAh) (%) (mAh) (%) (mAh) (%) (mAh) (%) (mAh) (%) 1.sup.st 232.2 90.61 231.7 90.00 235.4 89.83 235.6 89.59 239.0 90.85 (0.1 C) 3.sup.rd 224.4 99.55 225.6 99.56 229.4 99.56 231.2 99.57 232.3 99.63 (0.3 C) 50.sup.th 218.1 99.83 219.5 99.82 223.1 99.81 225.4 99.89 226.9 99.95 (0.3 C)

TABLE-US-00004 TABLE 2 Electrochemical performance of MEXI-3 - Cell Chemistry 2 Base electrolyte + Base electrolyte + Base electrolyte + Base electrolyte + Base electrolyte 2 wt. % MEXI-3 5 wt. % MEXI-3 10 wt. % MEXI-3 30 wt. % MEXI-3 Discharge Coulombic Discharge Coulombic Discharge Coulombic Discharge Coulombic Discharge Coulombic Cycle capacity efficiency capacity efficiency capacity efficiency capacity efficiency capacity efficiency No. (mAh) (%) (mAh) (%) (mAh) (%) (mAh) (%) (mAh) (%) 1.sup.st 199.6 74.52 199.0 74.25 197.8 73.82 198.1 74.37 199.7 74.68 (0.1 C) 3.sup.rd 176.3 97.03 176.9 97.16 176.9 97.19 177.1 97.40 178.9 97.54 (0.3 C) 50.sup.th 125.7 99.62 128.5 99.65 130.5 99.67 133.2 99.70 136.5 99.74 (0.3 C)

[0135] The test results for the additive MEXI-3 in each cell chemistry are summarised in Tables 1-2 and FIGS. 1-2. From this data it can be seen that the additive in both cell chemistries had a positive influence on cell performance improving both Coulombic efficiency and cycling stability. These results combined with the safety related studies demonstrate that the compounds of this invention simultaneously improved both the safety and performance of energy storage devices containing them.

FIGURES

[0136] FIGS. 1-2 show the test results for the additive ETFMP in each cell chemistry.