Cyanogroup-containing organofluoroborate additives for lithium-ion batteries

Abstract

Embodiments of the present disclosure relate to cyano-containing organofluoroborate additives for lithium-ion batteries. The present disclosure relates generally to battery cells, and more specifically to electrolyte additives for use in lithium-ion battery cells.

Description

[0001] Cross-references to Related Patent Applications

[0002] This patent application claims the benefit under 35 U.S.C. §119(e) of U.S. patent application 63 / 211,825, filed on June 17, 2021, entitled “Cyano-Containing Organofluoroborate Additives for Lithium Ion Batteries,” U.S. patent application 63 / 248,235, filed on September 24, 2021, entitled “Cyano-Containing Organofluoroborate Additives for Lithium Ion Batteries,” and U.S. patent application 63 / 248,214, filed on September 24, 2021, entitled “Cyano-Containing Organofluoroborate Additives for Lithium Ion Batteries,” each of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to battery cells, and more particularly to electrolyte additives used in lithium-ion battery cells.

[0004] U.S. Government Licensing Rights

[0005] This invention was made with U.S. Government support under WFO Proposal No. 85C85. This invention was made under CRADA 1500801 between Apple Inc. and Argonne National Laboratory (part of the U.S. Department of Energy). The U.S. Government has certain rights in this invention. Background Art

[0006] Lithium-ion batteries are widely used as power sources in consumer electronics. These products require lithium-ion batteries that can deliver higher volumetric energy density and sustain more discharge-charge cycles. Lithium-ion batteries typically operate at voltages as high as 4.45V (full cell voltage).

[0007] The battery life cycle may be shortened due to the instability of the cathode structure and electrolyte degradation. The stability of the cathode material can be improved by modification of LiCoO2 (such as doping and surface coating). Only limited progress has been made in developing electrolytes that can achieve both high volumetric energy density and long battery cycle life. Most existing electrolytes have poor ability to form a stable cathode-electrolyte (CEI) and / or solid-electrolyte interphase (SEI), resulting in rapid interfacial impedance growth and capacity decay. Summary of the Invention

[0008] In a first aspect, the present disclosure relates to an electrolyte fluid comprising at least 0.01 wt. % of an additive selected from compounds of Formula (I), Formula (II), Formula (III), and Formula (IV).

[0009]

[0010]

[0011] In a second aspect, the present disclosure relates to an electrolyte fluid comprising at least 0.01% by weight of an additive selected from compounds of formula (I), formula (II), and formula (III). The electrolyte fluid may comprise at least 0.01% by weight of a compound of formula (I). The electrolyte fluid may comprise at least 0.01% by weight of a compound of formula (II). The electrolyte fluid may comprise at least 0.01% by weight of a compound of formula (III). The electrolyte fluid may comprise at least 0.01% by weight of a compound of formula (IV).

[0012] When the additive is a compound of formula (I), m is an integer equal to or greater than 1 and equal to or less than 9, and M + Selected from alkali metal ions, quaternary ammonium ions, imidazolium ions and quaternary phosphonium ions.

[0013] When the additive is a compound of formula (II), m is an integer equal to or greater than 1 and equal to or less than 9, n is an integer equal to or greater than 1 and equal to or less than 9, and M + Selected from alkali metal ions, quaternary ammonium ions, imidazolium ions and quaternary phosphonium ions.

[0014] When the additive is a compound of formula (III), m is an integer equal to or greater than 1 and equal to or less than 9, n is an integer equal to or greater than 1 and equal to or less than 9, p is an integer equal to or greater than 1 and equal to or less than 9, and M + Selected from alkali metal ions, quaternary ammonium ions, imidazolium ions and quaternary phosphonium ions.

[0015] When the additive is a compound of formula (IV), m is an integer equal to or greater than 1 and equal to or less than 9, n is an integer equal to or greater than 1 and equal to or less than 9, p is an integer equal to or greater than 1 and equal to or less than 9, q is an integer equal to or greater than 1 and equal to or less than 9, and M + Selected from alkali metal ions, quaternary ammonium ions, imidazolium ions and quaternary phosphonium ions.

[0016] In some variations, the additive is an organic potassium trifluoroborate compound, potassium (cyanomethyl) trifluoroborate (PCTFB). In some variations, the additive is an organic potassium trifluoroborate, lithium (cyanomethyl) trifluoroborate (LiCTFB).

[0017] In some variations, the electrolyte fluid can be an electrolyte salt selected from the group consisting of: LiPF6, LiBF4, LiClO4, LiSO3CF3, LiN(SO2F)2, LiN(SO2CF3)2, LiBC4O8, Li[PF3(C2CF5)3], LiC(SO2CF3)3, and combinations thereof.

[0018] In some variations, the electrolyte fluid may comprise a solvent selected from the group consisting of ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethyl propionate (EP), butyl butyrate (BB), methyl acetate (MA), methyl butyrate (MB), methyl propionate (MP), propylene carbonate (PC), ethyl acetate (EA), propyl propionate (PP), butyl propionate (BP), propyl acetate (PA), butyl acetate (BA), and combinations thereof.

[0019] In some variations, the electrolyte fluid may include an additive selected from the group consisting of: (LiDFOB), prop-1-ene-1,3-sultone (PES), methylene methanedisulfonate (MMDS), vinyl ethylene carbonate (VEC), propane sultone (PS), fluoroethylene carbonate (FEC), succinonitrile (SN), vinyl carbonate (VC), adiponitrile (ADN), ethylene glycol bis(2-cyanoethyl) ether (EGPN), 1,3,6-hexanetrionitrile (HTCN), and combinations thereof.

[0020] In some variations, the present disclosure relates to a battery cell. The battery cell may include a positive electrode and a negative electrode, wherein the positive electrode has a positive electrode active material disposed on a positive electrode current collector, and the negative electrode has a negative electrode active material disposed on a negative electrode current collector. The negative electrode is oriented toward the positive electrode such that the negative electrode active material faces the positive electrode active material. A separator is disposed between the positive electrode active material and the negative electrode active material. An electrolyte fluid as described herein is disposed between the positive electrode and the negative electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present disclosure will be readily understood by the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals designate like structural elements, and in which:

[0022] Figure 1 is a top view of a battery cell according to an exemplary embodiment; and

[0023] Figure 2is a perspective view of a battery cell according to an exemplary embodiment;

[0024] Figure 3 Presents the cycling performance energy retention at cycle 201 for a cell operated at 45° C. for a control electrolyte compared to a control containing 0.5 wt % PCTFB according to an exemplary embodiment;

[0025] Figure 4 presents the RSS at cycle 201 for a cell operated at 45° C. for a control electrolyte compared to a control containing 0.5 wt % PCTFB, according to an exemplary embodiment;

[0026] Figure 5 presents a graph of cycling performance energy retention at cycle 200 of a control electrolyte at 45° C., compared to a control containing 0.5 wt % PCTFB, according to an exemplary embodiment;

[0027] Figure 6 depicts RSS as a function of battery cycle count at 45° C. for batteries having a control electrolyte and an electrolyte comprising 0.5 wt % PCTFB, according to an exemplary embodiment;

[0028] Figure 7 depicts the capacity recovery of different electrolyte compositions containing HTCN and optionally LiCTFB after battery storage at 85° C. for 8 hours, according to exemplary embodiments;

[0029] Figure 8 depicts improved lithium plating of different electrolyte compositions containing HTCN and optionally LiCTFB after cell operation at -3°C according to exemplary embodiments; and

[0030] Figure 9 Depicted is the formation of a solid-electrolyte interface according to an exemplary embodiment. DETAILED DESCRIPTION

[0031] Reference will now be made in detail to the representative embodiments shown in the accompanying drawings. It should be understood that the following description is not intended to limit the embodiments to one preferred embodiment. On the contrary, it is intended to cover alternatives, modifications and equivalents that may be included within the spirit and scope of the described embodiments as defined by the appended claims.

[0032] Figure 1A top view of a battery cell 100 according to one embodiment is shown. The battery cell 100 may correspond to a lithium ion or lithium polymer battery cell for powering devices used in consumer, medical, aerospace, defense, and / or transportation applications. The battery cell 100 includes a stack 102 having a plurality of layers, the plurality of layers including a positive electrode having a positive active coating, a separator, and a negative electrode having a negative active coating. More specifically, the stack 102 may include a strip of positive active material (e.g., aluminum foil coated with a lithium compound) and a strip of negative active material (e.g., copper foil coated with carbon). The stack 102 also includes a strip of separator material (e.g., a microporous polymer film or a non-woven fabric mat) disposed between the strip of positive active material and the strip of negative active material. The positive electrode, negative electrode, and separator layers may remain flat in a planar configuration or may be wound into a wound configuration (e.g., a "jelly roll"). An electrolyte solution is disposed between each positive and negative electrode.

[0033] During assembly of the battery cell 100, the stack 102 can be enclosed in a bag or container. The stack 102 can be in a planar or wound configuration, but other configurations are also possible. In some variations, the bag is such as a bag formed by folding a flexible sheet along a fold line 112. In some cases, the flexible sheet is made of aluminum with a polymer film (such as polypropylene). After folding the flexible sheet, the flexible sheet can be sealed, for example, by applying heat along the side seals 110 and along the platform seal 108. The thickness of the flexible bag can be less than or equal to 120 microns to improve the packaging efficiency of the battery cell 100, the density of the battery cell 100, or both.

[0034] The stack 102 may also include a set of conductive tabs 106 coupled to the positive and negative electrodes. The conductive tabs 106 may extend through a seal in the pouch (e.g., a seal formed using sealing tape 104) to provide terminals for the battery cell 100. The conductive tabs 106 may then be used to electrically couple the battery cell 100 with one or more other battery cells to form a battery pack. For example, a battery pack may be formed by coupling battery cells in series, parallel, or a series-parallel configuration. Such coupled cells may be enclosed in a rigid housing to complete the battery pack, or may be embedded within the housing of a portable electronic device such as a laptop computer, tablet computer, mobile phone, personal digital assistant (PDA), digital camera, and / or portable media player.

[0035] Figure 2 A battery cell 200 (eg, Figure 11 . The battery includes a positive electrode 202 and a negative electrode 210, wherein the positive electrode includes a current collector 204 and a positive electrode active material 206, and the negative electrode includes a negative electrode current collector 212 and a negative electrode active material 214. A separator 208 is disposed between the positive electrode 202 and the negative electrode 210. An electrolyte fluid 216 is disposed between the positive electrode 202 and the negative electrode 210 and in contact with the separator 208. To form a battery cell, the positive electrode 202, the separator 208, and the negative electrode 210 can be stacked in a planar configuration, or they can be stacked and then wound into a wound configuration. The electrolyte fluid 216 can then be added. Prior to assembling the battery cell, this set of layers can correspond to a cell stack.

[0036] The positive electrode current collector, the positive electrode active material, the negative electrode current collector, the negative electrode active material and the separator can be any material known in the art. In some variations, the positive electrode current collector can be aluminum foil and the negative electrode current collector can be copper foil. The positive electrode active material can be any material described in, for example, 14 / 206,654, 15 / 458,604, 15 / 458,612, 15 / 709,961, 15 / 710,540, 15 / 804,186, 16 / 531,883, 16 / 529,545, 16 / 999,307, 16 / 999,328, 16 / 999,265, each of which is incorporated herein by reference in its entirety.

[0037] The separator may include a microporous polymer film or a nonwoven fabric mat. Non-limiting examples of microporous polymer films or nonwoven fabric mats include microporous polymer films or nonwoven fabric mats of the following materials: polyethylene (PE), polypropylene (PP), polyamide (PA), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), polyester, and polyvinylidene fluoride (PVdF). However, other microporous polymer films or nonwoven fabric mats are also possible (e.g., gel polymer electrolytes).

[0038] Generally speaking, a separator refers to a structure in a battery, such as an intercalation layer, that prevents physical contact between the positive and negative electrodes while allowing ions to be transported between them. The separator is formed of a material having pores that provide ion transport pathways, which may include absorbing an electrolyte fluid containing ions. The material used for the separator can be selected based on chemical stability, porosity, pore size, permeability, wettability, mechanical strength, dimensional stability, softening temperature, and thermal shrinkage. These parameters may affect battery performance and safety during operation.

[0039] Generally speaking, the electrolyte fluid can serve as a conductive path for transferring cations from the negative electrode to the positive electrode during discharge.The electrolyte fluid comprises an electrolyte salt, an electrolyte solvent, and one or more electrolyte additives.

[0040] The electrolyte fluid comprises an electrolyte solvent. The electrolyte solvent can be any type of electrolyte solvent suitable for the battery cell. Non-limiting examples of electrolyte solvents include propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethyl propionate (EP), butyl butyrate (BB), methyl acetate (MA), methyl butyrate (MB), methyl propionate (MP), propylene carbonate (PC), ethyl acetate (EA), propyl propionate (PP), butyl propionate (BP), propyl acetate (PA) and butyl acetate (BA), or combinations thereof.

[0041] The electrolyte fluid also has one or more electrolyte salts dissolved therein. The salts can be any type of salt suitable for use in a battery cell. For example, but not limitation, salts used in lithium-ion battery cells include LiPF6, LiBF4, LiClO4, LiSO3CF3, LiN(SO2F)2, LiN(SO2CF3)2, LiBC4O8, Li[PF3(C2CF5)3], and LiC(SO2CF3)3. Other salts are also possible, including combinations of salts.

[0042] In some variations, the salt is at least 0.1M in the total electrolyte fluid. In some variations, the salt is at least 0.2M in the total electrolyte fluid. In some variations, the salt is at least 0.3M in the total electrolyte fluid. In some variations, the salt is at least 0.4M in the total electrolyte fluid. In some variations, the salt is at least 0.5M in the total electrolyte fluid. In some variations, the salt is at least 0.6M in the total electrolyte fluid. In some variations, the salt is at least 0.7M in the total electrolyte fluid. In some variations, the salt is at least 0.8M in the total electrolyte fluid. In some variations, the salt is at least 0.9M in the total electrolyte fluid. In some variations, the salt is at least 1.0M in the total electrolyte fluid. In some variations, the salt is at least 1.3M in the total electrolyte fluid. In some variations, the salt is at least 1.6M in the total electrolyte fluid. In some variations, the salt is at least 1.9 M in the total electrolyte fluid.

[0043] In some variations, the salt is less than or equal to 2.0M in the electrolyte fluid. In some variations, the salt is less than or equal to 1.9M in the electrolyte fluid. In some variations, the salt is less than or equal to 1.6M in the electrolyte fluid. In some variations, the salt is less than or equal to 1.3M in the electrolyte fluid. In some variations, the salt is less than or equal to 1.1M in the electrolyte fluid. In some variations, the salt is less than or equal to 1.0M in the electrolyte fluid. In some variations, the salt is less than or equal to 0.9M in the electrolyte fluid. In some variations, the salt is less than or equal to 0.8M in the electrolyte fluid.

[0044] In some variations, the salt is present in the electrolyte fluid at a concentration of less than or equal to 0.7 M. In some variations, the salt is present in the electrolyte fluid at a concentration of less than or equal to 0.6 M. In some variations, the salt is present in the electrolyte fluid at a concentration of less than or equal to 0.5 M. In some variations, the salt is present in the electrolyte fluid at a concentration of less than or equal to 0.4 M.

[0045] In some variations, the salt is less than or equal to 0.3 M in the electrolyte fluid. In some variations, the salt is less than or equal to 0.2 M in the electrolyte fluid.

[0046] In some variations, the present disclosure relates to electrolyte fluids comprising one or more cyano-containing organotrifluoroborate additives selected from compounds of Formula (I), (II), (III), or (IV).

[0047]

[0048]

[0049] In one variation, the electrolyte solution comprises an additive having a structure of formula (I), wherein m is not equal to 0. In some variations, increasing the value of m extends the carbon chain from boron, providing a greater probability that the cyano functional group can contact the positive electrode.

[0050] In some variations, m is 1. In some variations, m is 2. In some variations, m is 3. In some variations, m is 4. In some variations, m is 5. In some variations, m is 6. In some variations, m is 7. In some variations, m is 8. In some variations, m is 9.

[0051] In some variations, m is 1 to 9. In further variations, m is 1 to 3. In still further variations, m is 1 to 2.

[0052] In some variations, m is 1 or greater. In some variations, m is 2 or greater. In some variations, m is 3 or greater. In some variations, m is 4 or greater. In some variations, m is 5 or greater. In some variations, m is 6 or greater. In some variations, m is 7 or greater. In some variations, m is 8 or greater. In some variations, m is 9 or less. In some variations, m is 8 or less. In some variations, m is 7 or less. In some variations, m is 6 or less. In some variations, m is 5 or less. In some variations, m is 4 or less. In some variations, m is 3 or less. In some variations, m is 2 or less.

[0053] As used herein, the variable m indicates the carbon number. In other words, the structure is composed of The alkyl groups described can be saturated or unsaturated, branched, or straight chain alkyl groups. The term "alkyl" is specifically intended to include groups having any degree or level of saturation, i.e., groups having only carbon-carbon single bonds, groups having one or more carbon-carbon double bonds, groups having one or more carbon-carbon triple bonds, and groups having a mixture of carbon-carbon single bonds, carbon-carbon double bonds, and carbon-carbon triple bonds.

[0054] Where a specific level of saturation is intended, the expressions "alkyl," "alkenyl," and "alkynyl" may be used.

[0055] "Alkyl" refers to a saturated branched, straight-chain or cyclic alkyl group derived by removing a hydrogen atom from a single carbon atom of a parent alkane. Typical alkyl groups include, but are not limited to, methyl; ethyl; propyl, such as propan-1-yl, propan-2-yl (isopropyl), cyclopropan-1-yl, etc.; butyl, such as butan-1-yl, butan-2-yl (sec-butyl), 2-methyl-propan-1-yl (isobutyl), 2-methyl-propan-2-yl (tert-butyl), cyclobutan-1-yl, etc.; and the like.

[0056] "Alkenyl" refers to an unsaturated branched, straight chain or cyclic alkyl group having at least one carbon-carbon double bond derived by removing a hydrogen atom from a single carbon atom of a parent alkene. The group may be in a cis or trans configuration about the double bond. Typical alkenyl groups include, but are not limited to, ethenyl; propenyl such as prop-1-en-1-yl, prop-1-en-2-yl, prop-2-en-1-yl (allyl), prop-2-en-2-yl, cycloprop-1-en-1-yl; cycloprop-2-en-1-yl; butenyl such as but-1-en-1-yl, but-1-en-2-yl, 2-methyl-prop-1-en-1-yl, but-2-en-1-yl, but-2-en-1-yl, but-2-en-2-yl, but-1,3-dien-1-yl, but-1,3-dien-2-yl, cyclobut-1-en-1-yl, cyclobut-1-en-3-yl, cyclobut-1,3-dien-1-yl, etc.; and the like.

[0057] "Alkynyl" refers to an unsaturated branched, straight-chain or cyclic alkyl group having at least one carbon-carbon triple bond derived by removing a hydrogen atom from a single carbon atom of a parent alkyne. Typical alkynyl groups include, but are not limited to, ethynyl; propynyl, such as prop-1-yn-1-yl, prop-2-yn-1-yl, etc.; butynyl, such as but-1-yn-1-yl, but-1-yn-3-yl, but-3-yn-1-yl, etc.; and the like.

[0058] Depend on The alkyl group of limitation is replaced by one or more cyano groups.In some modifications, the hydrogen on the terminal carbon of cyano group replacement alkyl group.In some modifications, the terminal carbon of alkyl group can have one, two or three cyano groups and replace.For example, when n is 1 and alkyl group is methyl, carbon can be terminal carbon, can be replaced by cyano group mono-replacement (forming acetonitrile part), by cyano group di-replacement (forming malononitrile part), or by cyano group tri-replacement (forming methanetrinitrile part).Equally, each carbon in alkyl chain can have the hydrogen of one or more replacements.

[0059] Depend on Multiple carbons in the defined alkyl groups may be cyano substituted.

[0060] The cation M+ of formula (I), (II) or (III) can be any cation known in the art. In some variations, the cation is lithium (Li + ) and / or potassium (K + ). In some variations, the cation is Li + In some variations, the cation is K + .

[0061] In one variation, the electrolyte solution comprises an additive having the structure of formula (II).

[0062] The variables m and n may be varied independently of each other and in any combination, as detailed below.

[0063] Increasing the value of m extends the carbon chain from boron, providing a greater probability that the cyano functional group can contact the cathode.

[0064] In some variations, m is 1. In some variations, m is 2. In some variations, m is 3. In some variations, m is 4. In some variations, m is 5. In some variations, m is 6. In some variations, m is 7. In some variations, m is 8. In some variations, m is 9.

[0065] In some variations, m is 1 to 9. In further variations, m is 1 to 3. In still further variations, m is 1 to 2.

[0066] In some variations, m is 1 or greater. In some variations, m is 2 or greater. In some variations, m is 3 or greater. In some variations, m is 4 or greater. In some variations, m is 5 or greater. In some variations, m is 6 or greater. In some variations, m is 7 or greater. In some variations, m is 8 or greater. In some variations, m is 9 or less. In some variations, m is 8 or less. In some variations, m is 7 or less. In some variations, m is 6 or less. In some variations, m is 5 or less. In some variations, m is 4 or less. In some variations, m is 3 or less. In some variations, m is 2 or less.

[0067] Increasing the value of m and / or n extends the carbon chain from the boron, providing a greater probability that the cyano functional group can contact the cathode.

[0068] In some variations, n is 1. In some variations, n is 2. In some variations, n is 3. In some variations, n is 4. In some variations, n is 5. In some variations, n is 6. In some variations, n is 7. In some variations, n is 8. In some variations, n is 9.

[0069] In some variations, n is 1 to 9. In further variations, n is 1 to 3. In still further variations, n is 1 to 2.

[0070] In some variations, n is 1 or greater. In some variations, n is 2 or greater. In some variations, n is 3 or greater. In some variations, n is 4 or greater. In some variations, n is 5 or greater. In some variations, n is 6 or greater. In some variations, n is 7 or greater. In some variations, n is 8 or greater. In some variations, n is 9 or less. In some variations, n is 8 or less. In some variations, n is 7 or less. In some variations, n is 6 or less. In some variations, n is 5 or less. In some variations, n is 4 or less. In some variations, n is 3 or less. In some variations, n is 2 or less.

[0071] In one variation, the electrolyte solution comprises an additive having the structure of formula (III).

[0072] The variables m, n, and p can be varied independently of one another and in any combination, as detailed below. In some variations, increasing the value of m, n, and / or p extends the carbon chain from boron and can provide a greater likelihood that the cyano functional group can contact the positive electrode.

[0073] In some variations, m is 1. In some variations, m is 2. In some variations, m is 3. In some variations, m is 4. In some variations, m is 5. In some variations, m is 6. In some variations, m is 7. In some variations, m is 8. In some variations, m is 9.

[0074] In some variations, m is 1 to 9. In further variations, m is 1 to 3. In still further variations, m is 1 to 2.

[0075] In some variations, m is 1 or greater. In some variations, m is 2 or greater. In some variations, m is 3 or greater. In some variations, m is 4 or greater. In some variations, m is 5 or greater. In some variations, m is 6 or greater. In some variations, m is 7 or greater. In some variations, m is 8 or greater. In some variations, m is 9 or less. In some variations, m is 8 or less. In some variations, m is 7 or less. In some variations, m is 6 or less. In some variations, m is 5 or less. In some variations, m is 4 or less. In some variations, m is 3 or less. In some variations, m is 2 or less.

[0076] Increasing the value of n extends the carbon chain from boron, providing a greater probability that the cyano functional group can contact the cathode.

[0077] In some variations, n is 1. In some variations, n is 2. In some variations, n is 3. In some variations, n is 4. In some variations, n is 5. In some variations, n is 6. In some variations, n is 7. In some variations, n is 8. In some variations, n is 9.

[0078] In some variations, n is 1 to 9. In further variations, n is 1 to 3. In still further variations, n is 1 to 2.

[0079] In some variations, n is 1 or greater. In some variations, n is 2 or greater. In some variations, n is 3 or greater. In some variations, n is 4 or greater. In some variations, n is 5 or greater. In some variations, n is 6 or greater. In some variations, n is 7 or greater. In some variations, n is 8 or greater. In some variations, n is 9 or less. In some variations, n is 8 or less. In some variations, n is 7 or less. In some variations, n is 6 or less. In some variations, n is 5 or less. In some variations, n is 4 or less. In some variations, n is 3 or less. In some variations, n is 2 or less.

[0080] Increasing the value of p extends the carbon chain from boron, providing a greater probability that the cyano functional group can contact the cathode.

[0081] In some variations, p is 1. In some variations, p is 2. In some variations, p is 3. In some variations, p is 4. In some variations, p is 5. In some variations, p is 6. In some variations, p is 7. In some variations, p is 8. In some variations, p is 9.

[0082] In some variations, p is 1 to 9. In further variations, p is 1 to 3. In still further variations, p is 1 to 2.

[0083] In some variations, p is 1 or greater. In some variations, p is 2 or greater. In some variations, p is 3 or greater. In some variations, p is 4 or greater. In some variations, p is 5 or greater. In some variations, p is 6 or greater. In some variations, p is 7 or greater. In some variations, p is 8 or greater. In some variations, p is 9 or less. In some variations, p is 8 or less. In some variations, p is 7 or less. In some variations, p is 6 or less. In some variations, p is 5 or less. In some variations, p is 4 or less. In some variations, p is 3 or less. In some variations, p is 2 or less.

[0084] In one variation, the electrolyte solution includes an additive having the structure of formula (IV).

[0085] The variables m, n, p, and q can be varied independently of one another and in any combination, as detailed below. In some variations, increasing the values ​​of m, n, p, and / or q extends the carbon chain from boron and can provide a greater likelihood that the cyano functional group can contact the positive electrode.

[0086] In some variations, m is 1. In some variations, m is 2. In some variations, m is 3. In some variations, m is 4. In some variations, m is 5. In some variations, m is 6. In some variations, m is 7. In some variations, m is 8. In some variations, m is 9.

[0087] In some variations, m is 1 to 9. In further variations, m is 1 to 3. In still further variations, m is 1 to 2.

[0088] In some variations, m is 1 or greater. In some variations, m is 2 or greater. In some variations, m is 3 or greater. In some variations, m is 4 or greater. In some variations, m is 5 or greater. In some variations, m is 6 or greater. In some variations, m is 7 or greater. In some variations, m is 8 or greater. In some variations, m is 9 or less. In some variations, m is 8 or less. In some variations, m is 7 or less. In some variations, m is 6 or less. In some variations, m is 5 or less. In some variations, m is 4 or less. In some variations, m is 3 or less. In some variations, m is 2 or less.

[0089] Increasing the value of n extends the carbon chain from boron, providing a greater probability that the cyano functional group can contact the cathode.

[0090] In some variations, n is 1. In some variations, n is 2. In some variations, n is 3. In some variations, n is 4. In some variations, n is 5. In some variations, n is 6. In some variations, n is 7. In some variations, n is 8. In some variations, n is 9.

[0091] In some variations, n is 1 to 9. In further variations, n is 1 to 3. In still further variations, n is 1 to 2.

[0092] In some variations, n is 1 or greater. In some variations, n is 2 or greater. In some variations, n is 3 or greater. In some variations, n is 4 or greater. In some variations, n is 5 or greater. In some variations, n is 6 or greater. In some variations, n is 7 or greater. In some variations, n is 8 or greater. In some variations, n is 9 or less. In some variations, n is 8 or less. In some variations, n is 7 or less. In some variations, n is 6 or less. In some variations, n is 5 or less. In some variations, n is 4 or less. In some variations, n is 3 or less. In some variations, n is 2 or less.

[0093] Increasing the value of p extends the carbon chain from boron, providing a greater probability that the cyano functional group can contact the cathode.

[0094] In some variations, p is 1. In some variations, p is 2. In some variations, p is 3. In some variations, p is 4. In some variations, p is 5. In some variations, p is 6. In some variations, p is 7. In some variations, p is 8. In some variations, p is 9.

[0095] In some variations, p is 1 to 9. In further variations, p is 1 to 3. In still further variations, p is 1 to 2.

[0096] In some variations, p is 1 or greater. In some variations, p is 2 or greater. In some variations, p is 3 or greater. In some variations, p is 4 or greater. In some variations, p is 5 or greater. In some variations, p is 6 or greater. In some variations, p is 7 or greater. In some variations, p is 8 or greater. In some variations, p is 9 or less. In some variations, p is 8 or less. In some variations, p is 7 or less. In some variations, p is 6 or less. In some variations, p is 5 or less. In some variations, p is 4 or less. In some variations, p is 3 or less. In some variations, p is 2 or less.

[0097] Increasing the value of q extends the carbon chain from boron, providing a greater probability that the cyano functional group can contact the cathode.

[0098] In some variations, q is 1. In some variations, q is 2. In some variations, q is 3. In some variations, q is 4. In some variations, q is 5. In some variations, q is 6. In some variations, q is 7. In some variations, q is 8. In some variations, q is 9.

[0099] In some variations, q is 1 to 9. In further variations, q is 1 to 3. In still further variations, q is 1 to 2.

[0100] In some variations, q is 1 or greater. In some variations, q is 2 or greater. In some variations, q is 3 or greater. In some variations, q is 4 or greater. In some variations, q is 5 or greater. In some variations, q is 6 or greater. In some variations, q is 7 or greater. In some variations, q is 8 or greater. In some variations, q is 9 or less. In some variations, q is 8 or less. In some variations, q is 7 or less. In some variations, q is 6 or less. In some variations, q is 5 or less. In some variations, q is 4 or less. In some variations, q is 3 or less. In some variations, q is 2 or less.

[0101] When the additive is a compound of formula (IV), m is an integer equal to or greater than 1 and equal to or less than 9, n is an integer equal to or greater than 1 and equal to or less than 9, p is an integer equal to or greater than 1 and equal to or less than 9, q is an integer equal to or greater than 1 and equal to or less than 9, and M + Selected from alkali metal ions, quaternary ammonium ions, imidazolium ions and quaternary phosphonium ions.

[0102] In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 0.01% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 0.03% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 0.05% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 0.07% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 0.10% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 0.20% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 0.30% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 0.50% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 0.75% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 1.0% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 1.25% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 1.50% of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 1.75% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 2.00% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 2.25% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 2.50% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is at least 2.75% by weight of the electrolyte fluid.In some variations, the amount of additive selected from compounds of formula (I), (II), (III), and (IV) is at least 3.0% by weight of the electrolyte fluid. In some variations, the amount of additive selected from compounds of formula (I), (II), (III), and (IV) is at least 3.25% by weight of the electrolyte fluid. In some variations, the amount of additive selected from compounds of formula (I), (II), (III), and (IV) is at least 3.50% by weight of the electrolyte fluid. In some variations, the amount of additive selected from compounds of formula (I), (II), (III), and (IV) is at least 3.75% by weight of the electrolyte fluid. In some variations, the amount of additive selected from compounds of formula (I), (II), (III), and (IV) is at least 4.00% by weight of the electrolyte fluid. In some variations, the amount of additive selected from compounds of formula (I), (II), (III), and (IV) is at least 4.25% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from compounds of formula (I), (II), (III), and (IV) is at least 4.50% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from compounds of formula (I), (II), (III), and (IV) is at least 4.75% by weight of the electrolyte fluid.

[0103] In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 5.0% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 4.75% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 4.50% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 4.25% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 4.00% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 3.75% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 3.50% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 3.25% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 3.00% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 2.75% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 2.50% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 2.25% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 2.00% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 1.75% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 1.50% by weight of the electrolyte fluid. In some variations, the amount of additive selected from compounds of Formula (I), Formula (II), Formula (III), and Formula (IV) is equal to or less than 1.25% by weight of the electrolyte fluid.In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 1.00% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 0.75% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 0.50% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 0.30% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 0.20% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 0.10% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 0.08% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 0.06% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 0.04% by weight of the electrolyte fluid. In some variations, the amount of the additive selected from the compounds of formula (I), (II), (III), and (IV) is equal to or less than 0.03% by weight of the electrolyte fluid. In some variations, the amount of additive selected from compounds of Formula (I), Formula (II), Formula (III), and Formula (IV) is equal to or less than 0.02% by weight of the electrolyte fluid.

[0104] In some variations, the electrolyte fluid may include one or more additives. In various aspects, the additives may include any combination and amount range of the following: lithium difluoro(oxalato)borate (LiDFOB), prop-1-ene-1,3-sultone (PES), methylene methanedisulfonate (MMDS), vinyl ethylene carbonate (VEC), propane sultone (PS), fluoroethylene carbonate (FEC), succinonitrile (SN), vinyl carbonate (VC), adiponitrile (ADN), ethylene glycol bis(2-cyanoethyl) ether (EGPN), and / or 1,3,6-hexanetricarbonitrile (HTCN).

[0105] In some variations, LiDFOB comprises at least 0.1% by weight of the total electrolyte fluid. In some variations, LiDFOB comprises at least 0.2% by weight of the total electrolyte fluid. In some variations, LiDFOB comprises at least 0.3% by weight of the total electrolyte fluid. In some variations, LiDFOB comprises at least 0.4% by weight of the total electrolyte fluid. In some variations, LiDFOB comprises at least 0.5% by weight of the total electrolyte fluid. In some variations, LiDFOB comprises at least 0.6% by weight of the total electrolyte fluid. In some variations, LiDFOB comprises at least 0.7% by weight of the total electrolyte fluid. In some variations, LiDFOB comprises at least 0.8% by weight of the total electrolyte fluid. In some variations, LiDFOB comprises at least 0.9% by weight of the total electrolyte fluid. In some variations, LiDFOB comprises at least 1.0% by weight of the total electrolyte fluid. In some variations, LiDFOB comprises at least 1.3% by weight of the total electrolyte fluid. In some variations, LiDFOB comprises at least 1.6% by weight of the total electrolyte fluid. In some variations, LiDFOB is at least 1.9 wt % of the total electrolyte fluid.

[0106] In some variations, LiDFOB is less than or equal to 2.0% by weight of the total electrolyte fluid. In some variations, LiDFOB is less than or equal to 1.9% by weight of the total electrolyte fluid. In some variations, LiDFOB is less than or equal to 1.3% by weight of the total electrolyte fluid. In some variations, LiDFOB is less than or equal to 1.3% by weight of the total electrolyte fluid. In some variations, LiDFOB is less than or equal to 1.1% by weight of the total electrolyte fluid. In some variations, LiDFOB is less than or equal to 1.0% by weight of the total electrolyte fluid. In some variations, LiDFOB is less than or equal to 0.9% by weight of the total electrolyte fluid. In some variations, LiDFOB is less than or equal to 0.8% by weight of the total electrolyte fluid. In some variations, LiDFOB is less than or equal to 0.7% by weight of the total electrolyte fluid. In some variations, LiDFOB is less than or equal to 0.6% by weight of the total electrolyte fluid. In some variations, LiDFOB is less than or equal to 0.5% by weight of the total electrolyte fluid. In some variations, LiDFOB is less than or equal to 0.4 wt % of the total electrolyte fluid. In some variations, LiDFOB is less than or equal to 0.3 wt % of the total electrolyte fluid. In some variations, LiDFOB is less than or equal to 0.2 wt % of the total electrolyte fluid.

[0107] In some variations, the amount of PES is at least 0.5% by weight of the total electrolyte fluid. In some variations, the amount of PES is at least 0.6% by weight of the total electrolyte fluid. In some variations, the amount of PES is at least 0.9% by weight of the total electrolyte fluid. In some variations, the amount of PES is at least 1.3% by weight of the total electrolyte fluid. In some variations, the amount of PES is at least 1.6% by weight of the total electrolyte fluid. In some variations, the amount of PES is at least 1.9% by weight of the total electrolyte fluid. In some variations, the amount of PES is at least 2.2% by weight of the total electrolyte fluid. In some variations, the amount of PES is at least 2.5% by weight of the total electrolyte fluid. In some variations, the amount of PES is at least 2.8% by weight of the total electrolyte fluid. In some variations, the amount of PES is at least 3.1% by weight of the total electrolyte fluid.

[0108] In some variations, the amount of PES is less than or equal to 3.5% by weight of the total electrolyte fluid. In some variations, the amount of PES is less than or equal to 3.1% by weight of the total electrolyte fluid. In some variations, the amount of PES is less than or equal to 2.8% by weight of the total electrolyte fluid. In some variations, the amount of PES is less than or equal to 2.5% by weight of the total electrolyte fluid. In some variations, the amount of PES is less than or equal to 2.2% by weight of the total electrolyte fluid. In some variations, the amount of PES is less than or equal to 1.9% by weight of the total electrolyte fluid. In some variations, the amount of PES is less than or equal to 1.6% by weight of the total electrolyte fluid. In some variations, the amount of PES is less than or equal to 1.3% by weight of the total electrolyte fluid. In some variations, the amount of PES is less than or equal to 1.1% by weight of the total electrolyte fluid. In some variations, the amount of PES is less than or equal to 0.9% by weight of the total electrolyte fluid. In some variations, the amount of PES is less than or equal to 0.6% by weight of the total electrolyte fluid.

[0109] In some variations, the amount of MMDS is at least 0.1% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is at least 0.2% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is at least 0.3% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is at least 0.4% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is at least 0.5% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is at least 0.6% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is at least 0.7% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is at least 0.8% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is at least 0.9% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is at least 1.0% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is at least 1.1% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is at least 1.2% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is at least 1.3% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is at least 1.4% by weight of the total electrolyte fluid.

[0110] In some variations, the amount of MMDS is less than or equal to 1.5% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is less than or equal to 1.4% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is less than or equal to 1.3% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is less than or equal to 1.2% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is less than or equal to 1.1% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is less than or equal to 1.0% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is less than or equal to 0.9% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is less than or equal to 0.8% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is less than or equal to 0.7% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is less than or equal to 0.6% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is less than or equal to 0.5% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is less than or equal to 0.4% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is less than or equal to 0.3% by weight of the total electrolyte fluid. In some variations, the amount of MMDS is less than or equal to 0.2% by weight of the total electrolyte fluid.

[0111] In some variations, the amount of VEC is at least 0.1% by weight of the total electrolyte fluid. In some variations, the amount of VEC is at least 0.2% by weight of the total electrolyte fluid. In some variations, the amount of VEC is at least 0.3% by weight of the total electrolyte fluid. In some variations, the amount of VEC is at least 0.4% by weight of the total electrolyte fluid. In some variations, the amount of VEC is at least 0.5% by weight of the total electrolyte fluid. In some variations, the amount of VEC is at least 0.6% by weight of the total electrolyte fluid. In some variations, the amount of VEC is at least 0.7% by weight of the total electrolyte fluid. In some variations, the amount of VEC is at least 0.8% by weight of the total electrolyte fluid. In some variations, the amount of VEC is at least 0.9% by weight of the total electrolyte fluid.

[0112] In some variations, the amount of VEC is less than or equal to 0.9% by weight of the total electrolyte fluid. In some variations, the amount of VEC is less than or equal to 0.8% by weight of the total electrolyte fluid. In some variations, the amount of VEC is less than or equal to 0.7% by weight of the total electrolyte fluid. In some variations, the amount of VEC is less than or equal to 0.6% by weight of the total electrolyte fluid. In some variations, the amount of VEC is less than or equal to 0.5% by weight of the total electrolyte fluid. In some variations, the amount of VEC is less than or equal to 0.4% by weight of the total electrolyte fluid. In some variations, the amount of VEC is less than or equal to 0.3% by weight of the total electrolyte fluid. In some variations, the amount of VEC is less than or equal to 0.2% by weight of the total electrolyte fluid.

[0113] In some variations, the amount of FEC is at least 2% by weight of the total electrolyte fluid. In some variations, the amount of FEC is at least 4% by weight of the total electrolyte fluid. In some variations, the amount of FEC is at least 6% by weight of the total electrolyte fluid. In some variations, the amount of FEC is at least 8% by weight of the total electrolyte fluid. In some variations, the amount of FEC is less than or equal to 10% by weight of the total electrolyte fluid. In some variations, the amount of FEC is less than or equal to 8% by weight of the total electrolyte fluid. In some variations, the amount of FEC is less than or equal to 6% by weight of the total electrolyte fluid. In some variations, the amount of FEC is less than or equal to 4% by weight of the total electrolyte fluid.

[0114] In some variations, the amount of PS is at least 0.5% by weight of the total electrolyte fluid. In some variations, the amount of PS is at least 1.0% by weight of the total electrolyte fluid. In some variations, the amount of PS is at least 1.5% by weight of the total electrolyte fluid. In some variations, the amount of PS is at least 2.0% by weight of the total electrolyte fluid. In some variations, the amount of PS is at least 2.5% by weight of the total electrolyte fluid. In some variations, the amount of PS is at least 3.0% by weight of the total electrolyte fluid. In some variations, the amount of PS is at least 3.5% by weight of the total electrolyte fluid. In some variations, the amount of PS is at least 4.0% by weight of the total electrolyte fluid. In some variations, the amount of PS is at least 4.5% by weight of the total electrolyte fluid. In some variations, the amount of PS is at least 5.0% by weight of the total electrolyte fluid.

[0115] In some variations, the amount of PS is less than or equal to 6.0% by weight of the total electrolyte fluid. In some variations, the amount of PS is less than or equal to 5.5% by weight of the total electrolyte fluid. In some variations, the amount of PS is less than or equal to 5.0% by weight of the total electrolyte fluid. In some variations, the amount of PS is less than or equal to 4.5% by weight of the total electrolyte fluid. In some variations, the amount of PS is less than or equal to 4.0% by weight of the total electrolyte fluid. In some variations, the amount of PS is less than or equal to 3.5% by weight of the total electrolyte fluid. In some variations, the amount of PS is less than or equal to 3.0% by weight of the total electrolyte fluid. In some variations, the amount of PS is less than or equal to 2.5% by weight of the total electrolyte fluid. In some variations, the amount of PS is less than or equal to 2.0% by weight of the total electrolyte fluid. In some variations, the amount of PS is less than or equal to 1.5% by weight of the total electrolyte fluid. In some variations, the amount of PS is less than or equal to 1.0% by weight of the total electrolyte fluid.

[0116] In some variations, the amount of SN is at least 0.5% by weight of the total electrolyte fluid. In some variations, the amount of SN is at least 1.0% by weight of the total electrolyte fluid. In some variations, the amount of SN is at least 1.5% by weight of the total electrolyte fluid. In some variations, the amount of SN is at least 2.0% by weight of the total electrolyte fluid. In some variations, the amount of SN is at least 2.5% by weight of the total electrolyte fluid. In some variations, the amount of SN is at least 3.0% by weight of the total electrolyte fluid. In some variations, the amount of SN is at least 3.5% by weight of the total electrolyte fluid. In some variations, the amount of SN is at least 4.0% by weight of the total electrolyte fluid. In some variations, the amount of SN is at least 4.5% by weight of the total electrolyte fluid. In some variations, the amount of SN is at least 5.0% by weight of the total electrolyte fluid.

[0117] In some variations, the amount of SN is less than or equal to 6.0% by weight of the total electrolyte fluid. In some variations, the amount of SN is less than or equal to 5.5% by weight of the total electrolyte fluid. In some variations, the amount of SN is less than or equal to 5.0% by weight of the total electrolyte fluid. In some variations, the amount of SN is less than or equal to 4.5% by weight of the total electrolyte fluid. In some variations, the amount of SN is less than or equal to 4.0% by weight of the total electrolyte fluid. In some variations, the amount of SN is less than or equal to 3.5% by weight of the total electrolyte fluid. In some variations, the amount of SN is less than or equal to 3.0% by weight of the total electrolyte fluid. In some variations, the amount of SN is less than or equal to 2.5% by weight of the total electrolyte fluid. In some variations, the amount of SN is less than or equal to 2.0% by weight of the total electrolyte fluid. In some variations, the amount of SN is less than or equal to 1.5% by weight of the total electrolyte fluid. In some variations, the amount of SN is less than or equal to 1.0% by weight of the total electrolyte fluid.

[0118] In some variations, the amount of HTCN is at least 0.01% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is at least 0.1% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is at least 0.5% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is at least 1.0% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is at least 1.5% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is at least 2.0% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is at least 2.5% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is at least 3.0% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is at least 3.5% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is at least 4.0% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is at least 4.5% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is at least 5.0 wt % of the total electrolyte fluid. In some variations, the amount of HTCN is at least 5.5 wt % of the total electrolyte fluid.

[0119] In some variations, the amount of HTCN is less than or equal to 6.0% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is less than or equal to 5.5% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is less than or equal to 5.0% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is less than or equal to 4.5% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is less than or equal to 4.0% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is less than or equal to 3.5% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is less than or equal to 3.0% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is less than or equal to 2.5% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is less than or equal to 2.0% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is less than or equal to 1.5% by weight of the total electrolyte fluid. In some variations, the amount of HTCN is less than or equal to 1.0% by weight of the total electrolyte fluid.

[0120] The electrolyte solvent may also have a salt dissolved therein. The salt may be any type of salt suitable for use in a battery cell. For example, and not by way of limitation, salts used in lithium-ion battery cells include LiPF6, LiBF4, LiClO4, LiSO3CF3, LiN(SO2CF3)2, LiBC4O8, Li[PF3(C2CF5)3], and LiC(SO2CF3)3. Other salts are also possible, including combinations of salts.

[0121] Example

[0122] The examples are provided for illustrative purposes only. These examples are not intended to limit any embodiment disclosed herein to any application or theory of operation.

[0123] Example 1

[0124] Various cell characteristics were tested using the electrolyte fluid containing PCTFB and compared to cells having a control electrolyte fluid that did not contain PCTFB. The composition of the control electrolyte fluid is shown in Table 1.

[0125] Table 1

[0126]

[0127] Figure 3The energy retention at cycle 200 for a cell operated at 45°C is presented for a control electrolyte compared to a control containing 0.5 wt% PCTFB. When the control electrolyte was used in the absence of PCTFB, the energy retention at cycle 200 was approximately 60%. After adding 0.5 wt% PCTFB, the energy retention at cycle 200 exceeded 85%. The addition of PCTFB resulted in a significant increase in energy retention at high cycle times.

[0128] Example 2

[0129] Figure 4 The RSS at cycle 202 is presented for a control electrolyte and a control electrolyte containing PCTFB. In the absence of PCTFB, the cell resistance is substantially higher. In the absence of 0.5 wt% PCTFB, the resistance at cycle 202 is 200-250. When the electrolyte formulation contains 0.5 wt% PCTFB, the RSS is less than 75.

[0130] Example 3

[0131] Figure 5 Energy retention normalized to cycle 25 at 45°C as a function of cycle count is presented for cells with a control electrolyte and an electrolyte containing 0.5 wt.% PCTFB. The energy retention through 100 cycles is roughly similar. However, in the absence of PCTFB, the energy retention begins to decline sharply. The data demonstrate that the presence of PCTFB in the electrolyte substantially improves the energy retention in the cell as the cycle count increases.

[0132] Example 4

[0133] Figure 6 Plotted are RSS at 45°C as a function of battery cycle count for cells with a control electrolyte and an electrolyte containing 0.5 wt.% PCTFB. Three tests were measured with and without PCTFB. At 75 cycles, the RSS of the cells with and without PCTFB were roughly similar. However, in the absence of PCTFB, energy retention began to increase significantly. As the cycle count increased, the PCTFB in the electrolyte fluid substantially reduced the RSS in the cell.

[0134] The recovery capacities of battery cells having a control electrolyte fluid, a control electrolyte fluid having 0.3 wt % PCTFB, and a control electrolyte fluid having 0.3 wt % PCTFB after storage were measured. As depicted in Table 2, the battery cells having the control electrolyte fluid had lower recovery capacities than the battery cells having the electrolyte fluid containing 0.3 wt % PCTFB or 0.5 wt % PCTFB.

[0135] Table 2

[0136]

[0137] Example 5

[0138] Figure 7 The capacity recovery of different electrolyte compositions after battery storage at 85° C. is depicted. The electrolyte solvent composition is described in Table 3, and the additive composition is described in Table 4:

[0139] Table 3

[0140]

[0141] Table 4

[0142] Electrolyte Fluid No. LiDFOB VEC MMDS SN FEC PS LiCTFB PES HTCN 1 0.7 0.5 2 7 2.5 1.5 3 2 0.5 0.5 2 4 3 3 0.5 2 4 3 4 0.5 2 4 1 5 0.5 2 4 0.2 1

[0143] refer to Figure 7 Electrolyte fluids 1, 2, and 3 had 3.0 wt% HTCN, while electrolyte fluids 4 and 5 had 1.0 wt% HTCN. Improved high-temperature recovery capacity was observed by reducing the HTCN percentage to 1.0 wt%. The recovery capacity after introducing 0.2 wt% LiCTFB increased the high-temperature recovery capacity compared to the electrolyte composition without LiCTFB.

[0144] Figure 8 Low-temperature cycling of cells with electrolyte fluids containing different additive combinations is depicted. At low temperatures, lithium mobility can be reduced. The addition of HTCN leads to passivation of the cathode surface, which also increases internal resistance. The electrolyte fluid containing 3.0 wt% HTCN exhibits a lower, higher internal resistance compared to lower amounts of HTCN. The electrolyte fluid with 1 wt% HTCN shows a slight improvement compared to 3.0 wt% HTCN. The addition of 0.2 wt% LiCTFB provides higher capacity at lower temperatures.

[0145] Example 6

[0146] Without wishing to be bound by any particular mechanism or mode of action, the cyano functional group may act as a protectant to the cathode. Figure 9Depicted is a cobalt oxide or modified cobalt oxide (e.g., LiCoM) with an electrolyte 302. x O) positive electrode active material interface 300. The compound of formula (I), (II), (III) or (IV) can incorporate two CEI-forming functional groups CN and BF3 in a single structure. When the compound of formula (I), (II), (III) or (IV) encounters and absorbs into the positive electrode active material LiCoM x O surface, the compound can be oxidized to produce CEI 304 at the surface of the positive active material 306, thereby passivating the surface of the positive active material 306. The cyano functional group can bind cobalt, and the boron functional group can bind oxygen. x O) The presence of CN functional groups and / or BF3 functional groups bound to the positive electrode active material can inhibit the ability of other electrolyte components to contact the positive electrode active material and potentially degrade the positive electrode active material. In various variations, the compound of formula (I), (II), (III) or (IV) can have a lower impact on internal resistance than other passivating compounds.

[0147] Example 7

[0148] LiCTFB can be synthesized from potassium cations to lithium cations. The initial potassium cation compound is lithiated by combining the compound with LiBF4 to form a compound of formula (I), (II), (III), or (IV). This reaction results in the formation of LiCTFB and KBF4 precipitates.

[0149]

[0150] The electrolyte fluids described herein may be valuable in battery cells, including those used in electronic devices and consumer electronics. An electronic device herein may refer to any electronic device known in the art. For example, an electronic device may be a telephone such as a mobile phone and a landline phone, or any communication device such as a smartphone (including, for example, a ), and email sending / receiving devices. The electronic device may also be an entertainment device, including a portable DVD player, a conventional DVD player, a Blu-ray Disc player, a video game controller, a music player such as a portable music player (e.g., ). The electronic device may be part of a display, such as a digital display, a television monitor, an e-book reader, a portable web browser (e.g., ), a watch (e.g., Apple Watch), or a computer monitor. The electronic device may also be part of a device that provides control, such as controlling the flow of images, video, sound (e.g., Apple ), or it may be a remote control for an electronic device. Furthermore, the electronic device may be part of a computer or its accessories, such as a hard drive tower housing or case, a laptop computer housing, a laptop computer keyboard, a laptop computer trackpad, a desktop computer keyboard, a mouse, and a speaker. The negative electrode unit, lithium metal cell, and battery pack may also be used in devices such as watches or clocks.

[0151] For the purpose of illustration, the foregoing description uses specific nomenclature to provide a thorough understanding of the embodiments. However, it will be apparent to those skilled in the art that specific details are not required in order to practice the embodiments. Therefore, for the purpose of illustration and description, the foregoing description of the specific embodiments described herein is presented. They are not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to those skilled in the art that, in view of the above teachings, many modifications and variations are feasible.

Claims

1. An electrolyte fluid comprising at least 0.01% by weight of an additive selected from the group consisting of compounds of formula (IV): in m is an integer equal to or greater than 1 and equal to or less than 9, n is an integer equal to or greater than 1 and equal to or less than 9, p is an integer equal to or greater than 1 and equal to or less than 9, q is an integer equal to or greater than 1 and equal to or less than 9, and M + Selected from alkali metal ions, quaternary ammonium ions, imidazolium ions and quaternary phosphonium ions. The electrolyte fluid according to claim 1 , wherein m is 1 to 3. The electrolyte fluid according to claim 1 , wherein m is 1 to 2. The electrolyte fluid according to claim 1 , wherein n is 1 to 3. The electrolyte fluid according to claim 1 , wherein n is 1 to 2. The electrolyte fluid according to claim 1 , wherein p is 1 to 3. The electrolyte fluid according to claim 1 , wherein p is 1 to 2. The electrolyte fluid according to claim 1 , wherein q is 1 to 3. 9 . The electrolyte fluid according to claim 1 , wherein q is 1 to 2.

10. The electrolyte fluid according to claim 1 or 2, comprising an electrolyte salt selected from the group consisting of LiPF6, LiBF4, LiClO4, LiSO3CF3, LiN(SO2F)2, LiN(SO2CF3)2, LiBC4O8, Li[PF3(C2CF5)3], LiC(SO2CF3)3, and combinations thereof.

11. The electrolyte fluid of claim 10, wherein the salt comprises LiPF6.

12. The electrolyte fluid of claim 10, wherein the salt is 0.8M to 1.6M.

13. The electrolyte fluid according to claim 1 or 2, comprising a solvent selected from the group consisting of ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethyl propionate (EP), butyl butyrate (BB), methyl acetate (MA), methyl butyrate (MB), methyl propionate (MP), propylene carbonate (PC), ethyl acetate (EA), propyl propionate (PP), butyl propionate (BP), propyl acetate (PA) and butyl acetate (BA), and combinations thereof.

14. The electrolyte fluid of claim 13, wherein the solvent is selected from the group consisting of PC, EC, PP, EP, and combinations thereof.

15. The electrolyte fluid according to claim 13, wherein the solvent comprises PC, EC, PP, and EP.

16. The electrolyte fluid of claim 13, wherein PC is 2 wt% to 20 wt% of the electrolyte fluid, EC is 5 wt% to 40 wt% of the electrolyte fluid, PP is 20 wt% to 70 wt% of the electrolyte fluid, and / or EP is 10 wt% to 50 wt% of the electrolyte fluid.

17. The electrolyte fluid according to claim 1 or 2, comprising an additive selected from the group consisting of lithium difluoro(oxalato)borate (LiDFOB), prop-1-ene-1,3-sultone (PES), methylene methanedisulfonate (MMDS), propylene carbonate (PC), vinyl ethylene carbonate (VEC), propane sultone (PS), fluoroethylene carbonate (FEC), succinonitrile (SN), vinyl carbonate (VC), adiponitrile (ADN), ethylene glycol bis(2-cyanoethyl) ether (EGPN), 1,3,6-hexanetricarbonitrile (HTCN), and combinations thereof.

18. The electrolyte fluid of claim 17, wherein the additive is selected from the group consisting of LiDFOB, PES, MMDS, PS, FEC, SN, HTCN, and combinations thereof.

19. The electrolyte fluid of claim 18, wherein the additive comprises LiDFOB, PES, MMDS, PS, FEC, SN, and HTCN.

20. A battery cell, comprising: a positive electrode having a positive electrode active material disposed on a positive electrode current collector; a negative electrode having a negative electrode active material disposed on a negative electrode current collector, the negative electrode being oriented toward the positive electrode such that the negative electrode active material faces the positive electrode active material; a separator disposed between the positive electrode active material and the negative electrode active material; and An electrolyte fluid according to any preceding claim, provided between the positive and negative electrodes.

21. The battery cell of claim 20, wherein the energy retention of the battery cell at cycle 200 is increased by more than 10% compared to a battery cell including the electrolyte fluid in the absence of the additive.

22. The battery cell of claim 20 or 21, wherein the RSS of the battery cell at cycle 200 is reduced by at least 50% compared to a battery cell comprising the electrolyte fluid in the absence of the additive.

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