ELECTROLYTE COMPOSITION FOR BATTERIES

Abstract

An electrolyte composition for a battery contains a lithium salt dissolved in an organic solvent and 0.01 to less than 1 wt.% of lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide, lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide, or a combination thereof, based on the total weight of the electrolyte composition.

Description

INTRODUCTION

[0001] The present disclosure relates to batteries and methods for their manufacture. More particularly, the present disclosure relates to an electrolyte with improved electrochemical properties and methods for its manufacture.

[0002] Battery cells may contain an anode, a cathode, an electrolyte composition, and a separator. A battery cell may operate in charge mode, absorbing electrical energy. A battery cell may operate in discharge mode, releasing electrical energy. A battery cell may undergo charge and discharge cycles, with the battery first absorbing and storing electrical energy and then releasing electrical energy to an associated system. In vehicles that use electrical energy to provide motive power, the vehicle's battery cells may be charged, and the vehicle may then drive for a period of time, using the stored electrical energy to generate motive power.

[0003] A battery cell contains an electrolyte composition that provides lithium ion conduction pathways between the anode and the cathode. The electrolyte is an ion conductor. The electrolyte is also an electronically insulating material.

[0004] Hybrid-electric and fully electric powertrains (collectively referred to as “electric propulsion”) have various architectures, some of which use a battery system to power one or more electric traction motors.

[0005] CN 1 14 447 428 B, GB 2 606 515 A, and US 2020 / 0 119 397 A1 disclose further electrolyte compositions for lithium-ion batteries. Further electrolytes and lithium salts are disclosed in US 2017 / 0 040 640 A1, as well as in: Niedzicki, L. et al.: New type of imidazole-based salts designed specifically for lithium ion batteries. Electrochimica acta, 2010, Vol. 55, No. 4, pp. 1450-1454. SUMMARY

[0006] In an exemplary embodiment, the present disclosure provides an electrolyte composition for a battery, wherein the electrolyte composition contains a lithium salt dissolved in an organic solvent and 0.1 to 0.7 wt% of lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide, or a combination thereof, based on the total weight of the electrolyte composition; the lithium salt contains lithium hexafluorophosphate; and the organic solvent contains 0.5 to 3 mol of the lithium hexafluorophosphate per 1 liter of the organic solvent, as well as ethylene carbonate and dimethyl carbonate in a volume ratio of 1:4 to 1:1. The electrolyte composition further contains 1 to 10 wt% of fluoroethylene carbonate, based on the total weight of the electrolyte composition, and 0.5 to 10 wt% of vinylene carbonate, based on the total weight of the electrolyte composition.

[0007] In another exemplary embodiment, the lithium salt may further comprise lithium perchlorate, lithium tetrachloroaluminate, lithium iodide, lithium bromide, lithium thiocyanate, lithium tetrafluoroborate, lithium difluorooxalatoborate, lithium tetraphenylborate, lithium bis(oxalate)borate, lithium tetrafluorooxalatophosphate, lithium nitrate, lithium hexafluoroarsenate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonimide), lithium fluorosulfonylimide, lithium fluoroalkylphosphate, or a combination thereof.

[0008] In yet another exemplary embodiment, the organic solvent may contain a cyclic carbonate, a linear carbonate, an aliphatic carboxylic acid ester, a γ-lactone, a chain ether, a cyclic ether, a sulfur compound, or a combination thereof.

[0009] In yet another exemplary embodiment, the organic solvent may include ethylene carbonate, propylene carbonate, butylene carbonate, or a combination thereof, as well as dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, or a combination thereof.

[0010] In yet another exemplary embodiment, the fluoroethylene carbonate may be present in an amount of 1 to 5 wt.% based on the total weight of the electrolyte composition, and the vinylene carbonate may be present in an amount of 0.5 to 5 wt.% based on the total weight of the electrolyte composition.

[0011] In an exemplary embodiment, the present disclosure provides a battery including an anode, a cathode, and an electrolyte composition containing a lithium salt dissolved in an organic solvent and 0.1 to 0.7 wt% of lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide, or a combination thereof, based on the total weight of the electrolyte composition; the lithium salt contains lithium hexafluorophosphate; and the organic solvent contains 0.5 to 3 moles of the lithium hexafluorophosphate per 1 liter of the organic solvent, as well as ethylene carbonate and dimethyl carbonate in a volume ratio of 1:4 to 1:1. The electrolyte composition further contains 1 to 10 wt% of fluoroethylene carbonate, based on the total weight of the electrolyte composition, and 0.5 to 10 wt% of vinylene carbonate, based on the total weight of the electrolyte composition.

[0012] In addition to one or more of the features described herein, the anode may contain silicon.

[0013] In another exemplary embodiment, the anode may include silicon monoxide, lithium-doped silicon monoxide, or a combination thereof.

[0014] In yet another exemplary embodiment, the cathode may contain nickel.

[0015] In yet another exemplary embodiment, the cathode may include Li(1+x)Mn2O4, where 0.1 ≤ x ≤ 1; LiMn(2x)NixO4, where 0 ≤ x ≤ 0.5; LiCoO2; Li(NixMnyCoz)O2, where 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, and x + y + z = 1; LiNi(1-xy)CoxMyO2, where 0 <x<0,2, y<0,2, und M Al, Mg oder Ti ist; LiFePO4, LiMn2-xFexPO4, wobei 0 < x < 0,3; LiNiCoAlO2; LiMPO4, wobei M mindestens eines von Fe, Ni, Co, und Mn; Li(NixMnyCozAlp)O2 ist, wobei 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, 0 ≤ p ≤ 1, x + y + z + p = 1 (NCMA); LiNiMnCoO2; Li2FexM1 xPO4, wobei M Mn und / oder Ni ist, 0 ≤ x ≤ 1; LiMn2O4 (LMO); LiFeSiO4; LiNi0,6Mn0,2Co0,2O2 (NMC622), LiMnO2, LiNi0,5, Mn1,5O4, LiV2(PO4)3, Aktivkohle, Schwefel und eine Kombination davon enthalten.

[0016] In an exemplary embodiment, the present disclosure provides a device comprising an output component and a battery configured to supply electrical energy to the device, the battery including an anode, a cathode, and an electrolyte composition comprising a lithium salt dissolved in an organic solvent and 0.1 to 0.7 wt. % of lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide, or the combination thereof, based on the total weight of the electrolyte composition; the lithium salt contains lithium hexafluorophosphate; and the organic solvent contains 0.5 to 3 moles of the lithium hexafluorophosphate per 1 liter of the organic solvent; and ethylene carbonate and dimethyl carbonate in a volume ratio of 1:4 to 1:1. The electrolyte composition further contains 1 to 10 wt.-% fluoroethylene carbonate, based on the total weight of the electrolyte composition, and 0.5 to 10 wt.% vinylene carbonate, based on the total weight of the electrolyte composition.

[0017] The above features and advantages, as well as other features and advantages of the disclosure, will be readily apparent from the following detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Further features, advantages and details are listed only as examples in the following detailed description, which refers to the drawings in which: Fig. 1 schematically illustrates an exemplary battery having the disclosed electrolyte composition according to the present disclosure; Fig. Figure 2 schematically illustrates an exemplary device implemented in a vehicle equipped with the battery of Fig. 1 is equipped according to the present disclosure; Fig. 3 is a graph illustrating exemplary test results of a relationship between capacity retention of a battery and a number of operating cycles through which the battery is operated for a variety of electrolyte compositions, according to the present disclosure; Fig. 4 is a graph illustrating exemplary test results of a relationship between the specific capacity retention of a battery and a number of operating cycles through which the battery is operated for a variety of electrolyte compositions, according to the present disclosure; and Fig. 5 is a graph illustrating exemplary test results of a relationship between the specific capacity of a battery and a number of operating cycles the battery undergoes for a variety of electrolyte compositions, according to the present disclosure. DETAILED DESCRIPTION

[0019] The present invention provides an electrolyte composition according to claim 1, a battery according to claim 3, and a device according to claim 6. The following description is merely exemplary and is not intended to limit the present disclosure, its application, or uses. It should be understood that, throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0020] During battery operation, chemical reactions between the anode and the electrolyte composition cause the formation of a solid electrolyte interlayer (SEI layer) on the anode. Similarly, chemical reactions between the cathode and the electrolyte composition lead to the formation of a cathode-electrolyte interlayer (CEI) on a cathode. The SEI layer and the CEI layer form as films on the anode and cathode, respectively.

[0021] Increased stability of the SEI layer and the CEI layer can lead to excellent service life and increased capacity retention of the electrode in the anode and cathode, respectively.

[0022] Electrolyte compositions containing lithium hexafluorophosphate (LiPF6) can evolve reactive species, such as hydrofluoric acid (HF), when used in a battery. HF can affect the interfacial structures of the electrodes and lead to deterioration of the electrode surface, which can contribute to capacity reduction over multiple battery operating cycles.

[0023] A cathode may contain nickel and manganese. Over the course of several battery operating cycles, nickel and manganese may dissolve or leach from the cathode, contributing to a reduction in battery capacity.

[0024] Nickel-rich cathodes such as nickel-cobalt-manganese-aluminum (NCMA) can be sensitive to moisture. An electrolyte composition containing lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide, or a combination thereof is provided.

[0025] Lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide, or a combination thereof can suppress not only the hydrolysis of LiPF6 to form HF, but also the electrochemical performance of cells with a nickel-rich cathode (e.g., a cathode with more than 50 wt% nickel) and a silicon-containing anode. The presence of lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide, or a combination thereof in the specified concentration range can reduce the presence of HF in the electrolyte composition by suppressing the hydrolysis of LiPF6.

[0026] Lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide, or the combination thereof may provide a performance improvement at a relatively low concentration (e.g., less than 1% or 0.1 to 0.7%). Lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide, or the combination thereof may provide a performance improvement at such a concentration in a cell having an anode containing silicon, for example, in a cell having an anode containing lithium-doped silicon oxide and graphite and a cathode containing NCMA.

[0027] The disclosed electrolyte composition can provide a battery with excellent longevity. The battery can contain a silicon anode and a nickel cathode, e.g., a nickel-rich cathode. The disclosed electrolyte composition, which contains lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide, or a combination thereof, can contribute to excellent cycling performance and capacity retention. The fluoroethylene carbonate (FEC) and vinylene carbonate (VC) contained in the electrolyte composition can further contribute to excellent cycling performance and capacity retention.

[0028] The electrolyte composition contains 0.01 to 0.7 wt%, 0.1 to 0.7 wt% or 0.1 to 0.5 wt% lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide or a combination thereof, based on the total weight of the electrolyte composition.

[0029] The electrolyte composition contains 1 to 10 wt.% fluoroethylene carbonate, based on the total weight of the electrolyte composition. The electrolyte composition contains 0.5 to 10 wt.% vinylene carbonate, based on the total weight of the electrolyte composition. The electrolyte composition may contain 1 to 5 wt.% fluoroethylene carbonate, based on the total weight of the electrolyte composition. The electrolyte composition may contain 0.5 to 5 wt.% vinylene carbonate, based on the total weight of the electrolyte composition.

[0030] An electrolyte composition for a battery is provided. The electrolyte composition contains a lithium salt dissolved in an organic solvent or a mixture of organic solvents.

[0031] The lithium salt includes lithium hexafluorophosphate (LiPF6).

[0032] Suitable lithium salts may contain inert anions. Examples of other lithium salts that can be dissolved in an organic solvent or a mixture of organic solvents include lithium perchlorate (LiClO4), lithium tetrachloroaluminate (LiAlCl4), lithium iodide (LiI1), lithium bromide (LiBr), lithium thiocyanate (LiSCN), lithium tetrafluoroborate (LiBF4), lithium difluorooxalatoborate (LiBF2(C2O4)) (LiODFB), lithium tetraphenylborate (LiB(C6H5)4), lithium bis(oxalate)borate (LiB(C2O4)i2) (LiBOB), lithium tetrafluorooxalate phosphate (LiPF4(C2O4)) (LiFOP), lithium nitrate (LiNO3), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethanesulfonimide) (LiTFSI) (LiN(CF3SO2)2), lithium fluorosulfonylimide (LiN(FSO2)2) (LiFSI), lithium fluoroalkyl phosphate (LiFAP) (Li3O4P), or a combination thereof.

[0033] The lithium salt contains lithium hexafluorophosphate, present in an amount of 0.5 to 3 mol per 1 liter of the organic solvent. The organic solvent contains ethylene carbonate and dimethyl carbonate in a volume ratio of 1:4 to 1:1.

[0034] The lithium salt can be dissolved in a variety of other organic solvents, including: B. in an alkyl carbonate, such as a cyclic carbonate (e.g. ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC),), a linear carbonate (e.g. dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC)), an aliphatic carboxylic acid ester (e.g. methyl formate, methyl acetate, methyl propionate), a γ-lactone (e.g. γ-butyrolactone, γ-valerolactone), a chain ether (e.g. 1,2-dimethoxyethane (DME), 1,2-diethoxyethane, ethoxymethoxyethane), a cyclic ether (e.g. tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane (DOL)), a sulfur compound (e.g. sulfolane) or a combination thereof. The electrolyte material contains between 0.5 and 3 moles per liter (molar (M)) of lithium salt.If the electrolyte material has a lithium concentration of more than 2 M or ionic liquids, the electrolyte material may contain a diluent such as hydrofluoroether (HFE).

[0035] The disclosed electrolyte composition can be used with a variety of battery configurations. The anode of the battery may, for example, contain silicon (Si), silicon monoxide (SiO), modified silicon / silicon monoxide (Si / SiO) (i.e., carbon-coated Si / SiO), a silicon-carbon compound (Si / C), or a combination thereof. The anode may contain silicon, silicon monoxide (SiO), a lithium-doped silicon oxide (LixSiOx), such as a lithium-doped silicon monoxide (LixSiO), Si / C, or a combination thereof. The anode may further contain graphite.

[0036] The battery's cathode may contain nickel, for example, the cathode may be a nickel-rich cathode (e.g., with a relatively high nickel content). The battery's anode may contain silicon, and the battery's cathode may contain nickel, for example, the cathode may be a nickel-rich cathode.

[0037] The positive electrode may contain a layered lithium transition metal oxide. The positive electrode may contain, for example: Li(1+x)Mn2O4, where 0.1 ≤ x ≤ 1; LiMn(2x)NixO4, where 0 ≤ x ≤ 0.5; LiCoO2; Li(NixMnyCoz)O2, where 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, and x + y + z = 1; LiNi(1xy)CoxMyO2, where 0 <x<0,2, y<0,2, und M Al, Mg, oder Ti ist; LiFePO4, LiMn2 xFexPO4, wobei 0 < x < 0,3; LiNiCoAlO2; LiMPO4, wobei M mindestens eines von Fe, Ni, Co, und Mn ist; Li(NixMnyCozAlp)O2, wobei 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, 0 ≤ p ≤ 1, x + y + z + p = 1 (NCMA); LiNiMnCoO2; Li2FexM1 xPO4 (M = Mn und / oder Ni, 0 ≤ x ≤ 1); LiMn2O4 (LMO); LiFeSiO4; LiNi0,6Mn0,2Co0,2O2 (NMC622), LiMnO2, LiNi0,5,Mn1,5O4, LiV2(PO4)3, Aktivkohle, Schwefel (z. B. mehr als 60 Gew.-%, bezogen auf das Gesamtgewicht der positiven Elektrode) oder eine Kombination davon.

[0038] The disclosed electrolyte composition can be used in a variety of batteries, such as lithium-ion, lithium metal, and lithium sulfur-oxygen batteries.

[0039] A battery is provided. The battery includes an anode, a cathode, and the specified electrolyte composition. The electrolyte composition includes a lithium salt dissolved in an organic solvent. The electrolyte composition includes 0.1 to 0.7 wt% of lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide, or a combination thereof, based on the total weight of the electrolyte composition; the lithium salt includes lithium hexafluorophosphate; and the organic solvent includes 0.5 to 3 moles of lithium hexafluorophosphate per 1 liter of the organic solvent, as well as ethylene carbonate and dimethyl carbonate in a volume ratio of 1:4 to 1:1. The electrolyte composition further includes 1 to 10 wt% of fluoroethylene carbonate, based on the total weight of the electrolyte composition, and 0.5 to 10 wt% of vinylene carbonate, based on the total weight of the electrolyte composition.

[0040] A device is provided. The device includes a starting component and a battery configured to supply electrical energy to the device. The battery includes an anode, a cathode, and the specified electrolyte composition. The electrolyte composition includes a lithium salt dissolved in an organic solvent. The electrolyte composition further includes 0.1 to 0.7 wt. % of lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide, or a combination thereof, based on the total weight of the electrolyte composition; the lithium salt includes lithium hexafluorophosphate; and the organic solvent includes 0.5 to 3 moles of the lithium hexafluorophosphate per 1 liter of the organic solvent, and ethylene carbonate and dimethyl carbonate in a volume ratio of 1:4 to 1:1. The electrolyte composition further includes 1 to 10 wt.-% fluoroethylene carbonate, based on the total weight of the electrolyte composition, and 0.5 to 10 wt.% vinylene carbonate, based on the total weight of the electrolyte composition. The device may be a vehicle.

[0041] Referring now to the drawings, wherein like reference numerals refer to like features throughout the several views, Fig. 1 schematically illustrates an exemplary battery cell 100 having an anode 110, a cathode 120, a separator 130, and an electrolyte composition 140. The battery cell 100 enables the conversion of electrical energy to stored chemical energy in a charge cycle, and the battery cell 100 enables the conversion of stored chemical energy to electrical energy in a discharge cycle. A negative current collector 112 is illustrated as connected to the anode 110, and a positive current collector 122 is illustrated as connected to the cathode 120. The separator 130 is operable to separate the anode 110 from the cathode 120 and to enable ion transfer through the separator 130. The electrolyte composition 140 is a liquid or gel that forms a lithium ion conduction path between the anode 110 and the cathode 120.

[0042] The 100 battery cell can be used in a wide range of applications and powertrains. Fig. 2 schematically illustrates an exemplary device 200 (e.g., a battery electric vehicle (BEV)) having a battery pack 210 including a plurality of battery cells 100. The plurality of battery cells 100 may be connected together in various combinations, e.g., by connecting some in parallel and some in series, to achieve the supply of electrical energy at a desired voltage. The battery 210 is illustrated as being electrically connected to a motor-generator unit 220 that provides motive power to the vehicle 200. The motor-generator unit 220 may include an output component, e.g., an output shaft, that provides mechanical energy useful for providing motive power to the vehicle 200. Numerous variations of the vehicle 200 are conceivable, and the disclosure is not intended to be limited to the examples provided.

[0043] Certain features of the present technology are further illustrated by the following non-limiting examples. ExamplesComparison example 1

[0044] The electrolyte composition of Comparative Example 1 contained 1 mol per liter (molar (M)) of lithium hexafluorophosphate (LiPF6) in EC / DMC (volume ratio of EC:DMC of 3:7) and 2 wt% FEC. Example 1 (not according to the invention)

[0045] The electrolyte composition of Example 1, not according to the invention, contained 1 M LiPF6 in EC / DMC (volume ratio of EC:DMC of 3:7), 2 wt% FEC and 1 wt% lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide.

[0046] Fig. 3 is a graph 300 illustrating exemplary test results of a relationship between the capacity retention of a battery and a number of operating cycles through which the battery is operated for a variety of electrolyte compositions. An illustrated vertical axis 301 describes the capacity retention of the cell as a percentage of the original cell capacity. An illustrated horizontal axis 302 describes the number of operating cycles. Graph 310 illustrates Comparative Example 1, and graph 320 illustrates Example 1 (not according to the invention). An improvement in the capacity retention of the battery can be seen in graph 320, which shows an improvement in the capacity retention of the cell as a result of incorporating lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide. Comparison example 2

[0047] The electrolyte composition of Comparative Example 1 contained 1 M LiPF6 in EC / DMC (volume ratio of EC:DMC of 3:7). Comparison example 3

[0048] The electrolyte composition of Comparative Example 2 contained 1 M LiPF6 in EC / DMC (volume ratio of EC:DMC of 3:7) and 1 wt% lithium difluoro(oxalato)borate. Comparison example 4

[0049] The electrolyte composition of Comparative Example 3 contained 1 M LiPF6 in EC / DMC (volume ratio of EC:DMC of 3:7), 2 wt% fluoroethylene carbonate (FEC) and 1 wt% vinylene carbonate (VC). Example 2 (not according to the invention)

[0050] The electrolyte composition of Example 1, not according to the invention, contained 1 M LiPF6 in EC / DMC (volume ratio of EC:DMC of 3:7), 2 wt% FEC, 1 wt% VC and 0.1 wt% lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide. Example 3 (not according to the invention)

[0051] The electrolyte composition of Example 2, not according to the invention, contained 1 M LiPF6 in EC / DMC (volume ratio of EC:DMC of 3:7), 2 wt% FEC, 1 wt% VC and 0.5 wt% lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide. Example 4 (not according to the invention)

[0052] The non-inventive electrolyte composition of Example 3 contained 1 M LiPF6 in EC / DMC (volume ratio of EC:DMC of 3:7), 2 wt% FEC, 1 wt% VC and 1 wt% lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide.

[0053] Cells were formed using the electrolyte from each of the examples, a 20 wt% LiSiOx graphite anode, and a nickel-cobalt-manganese-aluminum (NCMA) cathode. Carboxymethylcellulose and polyvinylidene fluoride served as binders for the anode and cathode, respectively. The conductive additives were carbon black and carbon nanotubes. The separator was based on polypropylene and / or polyethylene.

[0054] Fig. 4 is a graph 400 illustrating exemplary test results of a relationship between the specific capacity retention of a battery and a number of operating cycles through which the battery is operated for a variety of electrolyte compositions. An illustrated vertical axis 401 describes the capacity retention of the cell as a percentage of the original cell capacity. An illustrated horizontal axis 402 describes the number of operating cycles. Graph 410 illustrates Comparative Example 2, graph 420 illustrates Comparative Example 3, graph 430 illustrates Comparative Example 4, graph 440 illustrates Example 2 (not according to the invention), graph 450 illustrates Example 3 (not according to the invention), and graph 460 illustrates Example 4 (not according to the invention).An improvement in the capacity retention of the battery can be seen in graphs 440, 450 and 460, which show an improvement in the capacity retention of the cell as a result of the inclusion of lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide.

[0055] Fig. 5 is a graph 500 illustrating exemplary test results of a relationship between the specific capacity of a battery and a number of operating cycles through which the battery is operated for a variety of electrolyte compositions. An illustrated vertical axis 501 describes a specific capacity of the cell in milliampere-hours per gram. An illustrated horizontal axis 502 describes the number of operating cycles. Graph 510 illustrates Comparative Example 2, graph 520 illustrates Comparative Example 3, graph 530 illustrates Comparative Example 4, graph 540 illustrates Example 2 (not according to the invention), graph 550 illustrates Example 3 (not according to the invention), and graph 560 illustrates Example 4 (not according to the invention).An improvement in battery-specific capacity retention can be seen in diagrams 540 and 550, which show an improvement in battery-specific capacity retention as a result of the inclusion of 0.1 to 0.5 wt% lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide, based on the total weight of the electrolyte composition.

[0056] With further reference to Fig. 5, the inclusion of VC can contribute to the stability of the solid electrolyte interlayer (SEI) with a silicon-containing anode. For an electrolyte containing VC, the inclusion of 0.1 to 0.5 wt% lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide, based on the total weight of the electrolyte composition, can lead to an improvement in battery-specific capacity retention.

[0057] The terms “ein”, “einer”, “eine”, “eines” and their declension forms do not imply a limitation of quantity, but indicate the presence of at least one of the named items. The term “or” means “and / or” unless the context clearly indicates otherwise. Whenever “an aspect” is mentioned throughout the description, this means that a particular element (e.g. a feature, structure, step or property) described in connection with the aspect is included in at least one of the aspects described therein and may or may not be present in other aspects. It is further understood that the elements described in the various aspects can be combined in any suitable way.

[0058] When an element such as a layer, film, region, or base film is described as lying "on top of" another element, it may lie directly on top of the other element, or there may be intervening elements. In contrast, when an element is described as lying "directly on top of" another element, there are no intervening elements.

[0059] Unless otherwise indicated herein, all examination standards are the most recent standard in effect as of the filing date of this application or, if priority is claimed, as of the filing date of the earliest priority application in which the examination standard appears.

[0060] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0061] While the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for elements without departing from the scope thereof. Furthermore, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, the present disclosure is not intended to be limited to the particular embodiments disclosed, but is intended to include all embodiments falling within its scope.

Claims

[1] An electrolyte composition for a battery, the electrolyte composition comprising: a lithium salt dissolved in an organic solvent; 0.1 to 0.7 wt% lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide or the combination thereof, based on the total weight of the electrolyte composition; 1 to 10 wt.% fluoroethylene carbonate, based on the total weight of the electrolyte composition; and 0.5 to 10 wt.% vinylene carbonate, based on the total weight of the electrolyte composition; wherein the lithium salt comprises lithium hexafluorophosphate; and the organic solvent comprises: 0.5 to 3 moles of lithium hexafluorophosphate per 1 liter of the organic solvent and Ethylene carbonate and dimethyl carbonate in a volume ratio of 1:4 to 1:

1. [2] The electrolyte composition according to claim 1, wherein: the fluoroethylene carbonate is present in an amount of 1 to 5 wt.%, based on the total weight of the electrolyte composition; and the vinylene carbonate is present in an amount of 0.5 to 5 wt.%, based on the total weight of the electrolyte composition. [3] Battery, comprising: an anode; a cathode and Electrolyte composition comprising: a lithium salt dissolved in an organic solvent; 0.1 to 0.7 wt% lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide or the combination thereof, based on the total weight of the electrolyte composition; 1 to 10 wt.% fluoroethylene carbonate, based on the total weight of the electrolyte composition; and 0.5 to 10 wt.% vinylene carbonate, based on the total weight of the electrolyte composition; wherein the lithium salt comprises lithium hexafluorophosphate; and the organic solvent comprises: 0.5 to 3 moles of lithium hexafluorophosphate per 1 liter of the organic solvent and Ethylene carbonate and dimethyl carbonate in a volume ratio of 1:4 to 1:

1. [4] The battery of claim 3, wherein the anode comprises silicon, silicon monoxide, a lithium-doped silicon monoxide, or a combination thereof. [5] A battery according to claim 3, wherein the cathode comprises: Li (1+x) Mn2O4, where 0.1 ≤ x ≤ 1; LiMn (2-x) Ni x O4, where 0 ≤ x ≤ 0.5; LiCoO2; Li(NiXMnYCo z )O2, where 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, and x + y + z = 1; LiNi (1-x-y) Co x M y O2, where 0 <x<0,2, y<0,2, und M Al, Mg, oder Ti ist; LiFePO4, LiMn 2-x Fe x PO4, where 0 < x < 0.3; LiNiCoAlO2; LiMPO4, where M is at least one of Fe, Ni, Co, and Mn; Li(Ni x Mn y Co z Alp )O2, where 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, 0 ≤ p ≤ 1, x + y + z + p = 1 (NCMA); LiNiMnCoO2; Li2Fe x M 1-x PO4, where M is Mn and / or Ni, 0 ≤ x ≤ 1; LiMn2O4 (LMO); LiFeSiO4; LiNi 0,6 Mn 0,2 Co 0,2 O2 (NMC622), LiMnO2, LiNi 0,5 ,Mn 1,5 O4, LiV2(PO4)3, activated carbon, sulfur and a combination thereof. [6] Device comprising: an output component; and a battery configured to supply electrical energy to the device, the battery comprising: an anode; a cathode and electrolyte composition comprising: a lithium salt dissolved in an organic solvent; 0.1 to 0.7 wt% lithium 4,5-dicyano-2-(pentafluoroethyl)imidazolide, lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide or the combination thereof, based on the total weight of the electrolyte composition; 1 to 10 wt.% fluoroethylene carbonate, based on the total weight of the electrolyte composition; and 0.5 to 10 wt.% vinylene carbonate, based on the total weight of the electrolyte composition; wherein the lithium salt comprises lithium hexafluorophosphate; and the organic solvent comprises: 0.5 to 3 moles of lithium hexafluorophosphate per 1 liter of the organic solvent and Ethylene carbonate and dimethyl carbonate in a volume ratio of 1:4 to 1:1.

Images