Ternary solvent electrolytes for high voltage and high rate lithium batteries

Abstract

Ternary electrolyte compositions having a primary solvent, a mediating solvent, a diluent, and at least one lithium salt are described.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 377,310, filed Sep. 27, 2022, which is incorporated herein by reference in its entirety for all purposes. Background Art

[0003] Under EV-related battery design constraints and battery cycling scenarios, carbonate solvents perform poorly in lithium metal batteries. It has been claimed in the literature that high-concentration and locally high-concentration electrolytes can solve the problems identified in conventional battery pack electrolyte systems. However, these electrolytes have poor rate performance. Even the best-performing of these electrolytes degrade rapidly under fast charging conditions. Currently, no single electrolyte solvent has been identified that can provide the electrochemical stability required for stable (300+ cycles) EV-related rate performance in high-energy density lithium metal batteries using high-voltage cathodes (at least 4.3 V) such as NMC.

[0004] LHCEs, which combine the kinetic stability provided by high-concentration salt-in-solvent electrolytes with improved ion transport through the incorporation of a diluent "solvent", are still limited in ion transport due to their relatively low conductivity and high viscosity, and also appear to face problems with poor interfacial charge transfer, which will limit high-rate (power) performance due to the inherent fact that Li + ions are trapped in a tight solvation shell in this design. The completely non-solvent behavior of electrochemically stable diluents provides an ionic insulating barrier to charge transport and charge transfer processes. Adding a third mediating solvent can overcome the barrier to Li + desolvation, thus improving the dynamic network within the electrolyte and therefore improving conductivity and rate performance, resulting in a more stable and long-lasting electrochemical cell for high-voltage, high-energy density lithium metal battery packs. Surprisingly, the present invention meets this need and others. Summary of the Invention

[0005] In one embodiment, the present invention provides an electrolyte composition comprising: a primary solvent; a mediating solvent; a diluent; and a first lithium salt, wherein the primary solvent, mediating solvent, and diluent are each different.

[0006] In another embodiment, the present invention provides an electrochemical device comprising: an anode; a cathode; a separator located between the anode and the cathode; and the electrolyte composition of the present invention. Brief Description of the Drawings

[0007] Figure 1 Shows a simulated Li+ coordination complex of an exemplary primary solvent, mediating solvent, and diluent.

[0008] Figure 2 Shows the graph of the relationship between the battery discharge capacity and the cycle life of lithium metal battery pack cells constructed using three different electrolytes. The curves represent the average discharge capacity of a set of lithium metal battery pack cells (n = 3 - 4). The cells were charged at 3.8 mAh / cm 2 and discharged at a current density of 1.9 mAh / cm 2 from 3.0 V to 4.3 V. Two ternary blended electrolytes (Electrolyte 1 - 4 and Electrolyte 2 - 1) were compared with a locally high - concentration electrolyte (Electrolyte E5) prepared according to the published experimental details (Battery Pack 500 - Nat. Energy, 6, 2021, 723 - 732.).

[0009] Figure 3 Shows the graph of the relationship between the battery discharge capacity and the cycle life of lithium metal battery pack cells constructed using five different electrolytes. The curves represent the average discharge capacity of a set of lithium metal battery pack cells (n = 4). The cells were charged at 1.27 mAh / cm 2 and discharged at a current density of 1.27 mAh / cm 2 from 3.0 V to 4.3 V. Four ternary blended electrolytes (Electrolyte 1 - 4, Electrolyte 2 - 1, Electrolyte 1 - 2, and Electrolyte 1 - 3) were compared with a locally high - concentration electrolyte (Electrolyte E5) prepared according to the published experimental details (Battery Pack 500 - Nat. Energy, 6, 2021, 723 - 732.).

[0010] Figure 4 Shows the graph of the relationship between the battery discharge capacity and the cycle life of lithium metal battery pack cells constructed using two different ternary blended electrolytes. The curves represent the average discharge capacity of a set of lithium metal battery pack cells (n = 3). The cells were charged at 0.76 mAh / cm 2 and discharged at a current density of 3.8 mAh / cm 2 from 3.0 V to 4.2 V.

[0011] Figure 5 Shows the graph of the relationship between the battery discharge capacity and the cycle life of lithium metal battery pack cells constructed using six different ternary blended electrolytes. The curves represent the average discharge capacity of a set of lithium metal battery pack cells (n = 4). The cells were charged at 0.76 mAh / cm 2 and discharged at a current density of 3.8 mAh / cm 2 from 3.0 V to 4.3 V.

[0012] Figure 6Shows a graph of the battery discharge capacity versus cycle life of a lithium metal battery cell containing a PIM-13 coated separator constructed using three different electrolytes. The curves represent the average discharge capacity of a set of lithium metal battery cells (n = 3 - 4). The cells were cycled at a current density of 1.27 mAh / cm 2 charging and 1.27 mAh / cm 2 discharging from 3.0 V to 4.3 V. Two ternary blend electrolytes (Electrolyte 1-4 and Electrolyte 2-1) were compared with a carbonate electrolyte (Electrolyte E4). Detailed Description

[0013] I. General Overview

[0014] The present invention provides a ternary electrolyte composition having at least one lithium salt and three different liquid components, the three different liquid components including a primary solvent having a high coordination strength with lithium ions, a mediating solvent having a medium to weak coordination strength with lithium ions, and a diluent having a low coordination strength with lithium ions. The ternary electrolyte composition may further comprise a second lithium salt and additives.

[0015] II. Definitions

[0016] "Electrolyte" or "electrolyte composition" refers to a solution of an electrochemical cell that contains ions such as metal ions and protons as well as anions, which provides ionic connectivity between a positive electrode and a negative electrode.

[0017] "Electrolyte solvent" refers to a molecule that solvates ions in a liquid electrolyte, such as a small organic molecule, which enables the ions to diffuse in the electrolyte. The electrolyte solvent may also be an ionic liquid or a gas at standard temperature and pressure.

[0018] "Primary solvent" refers to a solvent having a high Li + coordination strength capable of dissolving a lithium salt and a relatively low molecular weight.

[0019] "Mediating solvent" refers to a solvent having a low to medium Li + coordination strength and being substantially miscible with both the primary solvent and the diluent.

[0020] "Diluent" refers to a non-solvent having a low Li + coordination strength that allows the primary solvent to occupy the first solvation shell of Li + . The lithium salts of the present invention are substantially insoluble in the diluent. The diluent is substantially miscible with the mediating solvent. The diluent can also reduce the viscosity of the electrolyte composition.

[0021] "Lithium salt" refers to an inorganic salt having a lithium ion Li + and an anion counterion.

[0022] "Ether" refers to a chemical compound of the formula R 1 -O-R 2 wherein R 1 and R 2 may be the same or different and are typically alkyl, haloalkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl. R 1 and R 2 may also combine to form a cyclic ether. Representative ethers include, but are not limited to, dimethyl ether, diethyl ether, oxirane, tetrahydrofuran, pyran, and 1,4-dioxane. When one of R 1 and R 2 is fluorinated, a fluorinated ether is formed.

[0023] "Glyme" refers to a chemical compound having two ether groups, as represented by the formula R 3 -O-alkylene-O-R 4 wherein R 3 and R 4 may be the same or different and are typically alkyl, haloalkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl. Representative glymes include, but are not limited to, monoglyme (1,2-dimethoxyethane), diglyme (diethylene glycol dimethyl ether), and triglyme (triethylene glycol dimethyl ether). When one of R 3 and R 4 is fluorinated, a fluorinated glyme is formed.

[0024] "Carbonate" refers to a chemical compound represented by the formula R 5 -O-C(O)-O-R 6 wherein R 5 and R 6 may be the same or different and are typically alkyl, haloalkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl, or may combine to form a cyclic carbonate. Representative carbonates include, but are not limited to, ethylene carbonate or fluoroethylene carbonate (FEC). When one of R 5 and R 6 is fluorinated, a fluorinated carbonate is formed.

[0025] "Alkyl" refers to a straight-chain or branched-chain saturated aliphatic group having the indicated number of carbon atoms. Alkyl may contain any number of carbons, such as C 1-2 、C 1-3 、C 1-4 、C 1-5 、C 1-6 、C 1-7 、C 1-8 、C 1-9 、C 1-10 、C 2-3 、C 2-4 、C2-5 , C 2-6 , C 3-4 , C 3-5 , C 3-6 , C 4-5 , C 4-6 and C 5-6 . For example, C 1-6 alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, hexyl, etc. An alkyl group can also refer to an alkyl group having up to 20 carbon atoms, such as, but not limited to, heptyl, octyl, nonyl, decyl, etc. The alkyl group can be substituted or unsubstituted.

[0026] "Alkylene" refers to a straight-chain or branched-chain saturated aliphatic group having the specified number of carbon atoms and connecting at least two other groups, i.e., a divalent hydrocarbon group. The two moieties connected to the alkylene can be connected to the same atom or different atoms of the alkylene group. For example, a straight-chain alkylene can be the divalent group -(CH2) n- , where n is 1, 2, 3, 4, 5 or 6. Representative alkylene groups include, but are not limited to, methylene, ethylene, propylene, isopropylene, butylene, isobutylene, sec-butylene, pentylene and hexylene. The alkylene group can be substituted or unsubstituted.

[0027] "Alkenyl" refers to a straight-chain or branched-chain hydrocarbon having at least 2 carbon atoms and at least one double bond. The alkenyl can contain any number of carbons, such as C2, C 2-3 , C 2-4 , C 2-5 , C 2-6 , C 2-7 , C 2-8 , C 2-9 , C 2-10 , C3, C 3-4 , C 3-5 , C 3-6 , C4, C 4-5 , C 4-6 , C5, C 5-6 and C6. The alkenyl group can have any suitable number of double bonds, including, but not limited to, 1, 2, 3, 4, 5 or more. Examples of alkenyl groups include, but are not limited to, vinyl / ethenyl, propenyl, isopropenyl, 1-butenyl, 2-butenyl, isobutenyl, butadienyl, 1-pentenyl, 2-pentenyl, isopentenyl, 1,3-pentadienyl, 1,4-pentadienyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 1,3-hexadienyl, 1,4-hexadienyl, 1,5-hexadienyl, 2,4-hexadienyl or 1,3,5-hexatriene. The alkenyl group can be substituted or unsubstituted.

[0028] "Alkynyl" means a straight-chain or branched-chain hydrocarbon having at least 2 carbon atoms and at least one triple bond. Alkynyl can contain any number of carbons, such as C2, C 2-3 , C 2-4 , C 2-5 , C 2-6 , C 2-7 , C 2-8 , C 2-9 , C 2-10 , C3, C 3-4 , C 3-5 , C 3-6 , C4, C 4-5 , C 4-6 , C5, C 5-6 and C6. Examples of alkynyl groups include, but are not limited to, ethynyl, propynyl, 1-butynyl, 2-butynyl, butadiynyl, 1-pentynyl, 2-pentynyl, isopentynyl, 1,3-pentadiynyl, 1,4-pentadiynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl, 1,3-hexadiynyl, 1,4-hexadiynyl, 1,5-hexadiynyl, 2,4-hexadiynyl or 1,3,5-hexatriynyl. The alkynyl group can be substituted or unsubstituted.

[0029] "Halogen" means fluorine, chlorine, bromine and iodine.

[0030] "Haloalkyl" means an alkyl group as defined above, wherein some or all of the hydrogen atoms are replaced with halogen atoms. Like alkyl groups, haloalkyl groups can have any suitable number of carbon atoms, such as C 1-6 . For example, haloalkyl includes trifluoromethyl, fluoromethyl, etc. In some cases, the term "perfluoro" can be used to define a compound or group in which all hydrogens are replaced with fluorine. For example, perfluoromethyl means 1,1,1-trifluoromethyl.

[0031] "Haloalkylene" means an alkylene group as defined above, wherein some or all of the hydrogen atoms are replaced with halogen atoms. Like alkyl groups, haloalkylene groups can have any suitable number of carbon atoms, such as C 2-6 , C 2-4 , C 3-6 or C 4-6 . For example, haloalkylene includes 2,2,3,3-tetrafluorobutylene, etc.

[0032] "Cycloalkyl" means a saturated or partially unsaturated, monocyclic, fused bicyclic or bridged polycyclic ring assembly containing 3 to 12 ring atoms or the indicated number of atoms. Cycloalkyl can contain any number of carbons, such as C 3-6 , C 4-6 , C 5-6 , C 3-8 , C4-8 , C 5-8 , C 6-8 , C 3-9 , C 3-10 , C 3-11 and C 3-12 . Saturated monocyclic cycloalkyl rings include, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cyclooctyl. Saturated bicyclic and polycyclic cycloalkyl rings include, for example, norbornane, [2.2.2]bicyclooctane, decalin, and adamantane. The cycloalkyl group can also be partially unsaturated, having one or more double or triple bonds in the ring. Representative partially unsaturated cycloalkyl groups include, but are not limited to, cyclobutene, cyclopentene, cyclohexene, cyclohexadiene (1,3- and 1,4-isomers), cycloheptene, cycloheptadiene, cyclooctene, cyclooctadiene (1,3-, 1,4-, and 1,5-isomers), norbornene, and norbornadiene. When the cycloalkyl is a saturated monocyclic C 3-8 cycloalkyl, exemplary groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. When the cycloalkyl is a saturated monocyclic C 3-6 cycloalkyl, exemplary groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. The cycloalkyl group can be substituted or unsubstituted.

[0033] "Cycloalkylene" refers to a cycloalkyl group having the indicated number of carbon atoms and connecting at least two other groups, i.e., a divalent group. The two moieties connected to the cycloalkylene can be connected to the same atom or different atoms of the cycloalkylene group. Examples of cycloalkylene rings include cyclopropylene, cyclobutylene, cyclopentylene, and cyclohexylene, etc. The cycloalkylene group can be 1,1-, 1,2-, 1,3- or 1,4-connected. For example, the cyclohexylene ring can adopt various conformations, including the boat conformation and the chair conformation. The chair conformation of cyclohexylene can have substituents in the axial or equatorial direction. The divalent nature of cycloalkylene results in cis and trans formations, where cis means that both substituents are on the same side (top or bottom) of the cycloalkylene ring, and where trans means that the substituents are on opposite sides of the cycloalkylene ring. For example, cis-1,2- and cis-1,4-cyclohexylene can have one substituent in the axial direction and the other substituent in the equatorial direction, while trans-1,2- and trans-1,4-cyclohexylene have both substituents in the axial or equatorial direction. The two substituents of cis-1,3-cyclohexylene are both in the axial or equatorial direction, while trans-1,3-cyclohexylene can have one substituent in the axial direction and the other substituent in the equatorial direction. The cycloalkylene group can be substituted or unsubstituted.

[0034] "Heterocycloalkyl" refers to a saturated ring system having from 3 to 12 ring members and from 1 to 4 heteroatoms of N, O, and S. Additional heteroatoms may also be available, including but not limited to B, Al, Si, and P. The heteroatoms may also be oxidized, such as but not limited to -S(O)- and S(O)2-. The heterocycloalkyl group may contain any number of ring atoms, such as 3 to 6, 4 to 6, 5 to 6, 3 to 8, 4 to 8, 5 to 8, 6 to 8, 3 to 9, 3 to 10, 3 to 11, or 3 to 12 ring members. The heterocycloalkyl group may contain any suitable number of heteroatoms, such as 1, 2, 3, or 4, or 1 to 2, 1 to 3, 1 to 4, 2 to 3, 2 to 4, or 3 to 4. The heterocycloalkyl group may include groups such as aziridine, azetidine, pyrrolidine, piperidine, azepane, azocane, quinuclidine, pyrazolidine, imidazolidine, piperazine (1,2-, 1,3-, and 1,4-isomers), oxirane, oxetane, tetrahydrofuran, oxane (tetrahydropyran), oxepane, thiirane, thietane, thiolane (tetrahydrothiophene), thiane (tetrahydrothiopyran), oxazolidine, isoxazolidine, thiazolidine, isothiazolidine, dioxolane, dithiolane, morpholine, thiomorpholine, dioxane, or dithiane. The heterocycloalkyl group may also be fused to an aromatic or non-aromatic ring system to form members including but not limited to indoline. The heterocycloalkyl group may be unsubstituted or substituted. For example, the heterocycloalkyl group may be substituted by C 1-6 alkyl or oxo (=O), etc.

[0035] The heterocycloalkyl group may be attached via any position on the ring. For example, aziridine may be 1- or 2-aziridine, azetidine may be 1- or 2-azetidine, pyrrolidine may be 1-, 2-, or 3-pyrrolidine, piperidine may be 1-, 2-, 3-, or 4-piperidine, pyrazolidine may be 1-, 2-, 3-, or 4-pyrazolidine, imidazolidine may be 1-, 2-, 3-, or 4-imidazolidine, piperazine may be 1-, 2-, 3-, or 4-piperazine, tetrahydrofuran may be 1- or 2-tetrahydrofuran, oxazolidine may be 2-, 3-, 4-, or 5-oxazolidine, isoxazolidine may be 2-, 3-, 4-, or 5-isoxazolidine, thiazolidine may be 2-, 3-, 4-, or 5-thiazolidine, isothiazolidine may be 2-, 3-, 4-, or 5-isothiazolidine, and morpholine may be 2-, 3-, or 4-morpholine.

[0036] When the heterocycloalkyl group contains 3 to 8 ring members and 1 to 3 heteroatoms, representative members include, but are not limited to, pyrrolidine, piperidine, tetrahydrofuran, oxane, tetrahydrothiophene, thiane, pyrazolidine, imidazolidine, piperazine, oxazolidine, isoxazolidine, thiazolidine, isothiazolidine, morpholine, thiomorpholine, dioxane, and dithiane. The heterocycloalkyl group can also form a ring having 5 to 6 ring members and 1 to 2 heteroatoms, and representative members include, but are not limited to, pyrrolidine, piperidine, tetrahydrofuran, tetrahydrothiophene, pyrazolidine, imidazolidine, piperazine, oxazolidine, isoxazolidine, thiazolidine, isothiazolidine, and morpholine.

[0037] "Aryl" refers to an aromatic ring system having any suitable number of ring atoms and any suitable number of rings. The aryl group can contain any suitable number of ring atoms, such as 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16 ring atoms, and 6 to 10, 6 to 12, or 6 to 14 ring members. The aryl group can be monocyclic, fused to form a bicyclic or tricyclic group, or linked by a bond to form a biaryl group. Representative aryl groups include phenyl, naphthyl, and biphenyl. Other aryl groups include benzyl with a methylene linking group. Some aryl groups have 6 to 12 ring members, such as phenyl, naphthyl, or biphenyl. Other aryl groups have 6 to 10 ring members, such as phenyl or naphthyl. Some other aryl groups have 6 ring members, such as phenyl. The aryl group can be substituted or unsubstituted.

[0038] "Heteroaryl" refers to a monocyclic or fused bicyclic or tricyclic aromatic ring assembly containing 5 to 16 ring atoms, wherein 1 to 5 ring atoms are heteroatoms such as N, O or S. Additional heteroatoms may also be available, including but not limited to B, Al, Si and P. The heteroatoms may also be oxidized, such as but not limited to -S(O)- and -S(O)2-. The heteroaryl group may contain any suitable number of ring atoms, such as 5 to 6, 5 to 8, 6 to 8, 5 to 9, 5 to 10, 5 to 11 or 5 to 12 ring members. The heteroaryl group may contain any suitable number of heteroatoms, such as 1, 2, 3, 4 or 5, or 1 to 2, 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, 2 to 5, 3 to 4 or 3 to 5. The heteroaryl group may have 5 to 8 ring members and 1 to 4 heteroatoms, or 5 to 8 ring members and 1 to 3 heteroatoms, or 5 to 6 ring members and 1 to 4 heteroatoms, or 5 to 6 ring members and 1 to 3 heteroatoms. The heteroaryl group may include groups such as pyrrole, pyridine, imidazole, pyrazole, triazole, tetrazole, pyrazine, pyrimidine, pyridazine, triazine (1,2,3-, 1,2,4- and 1,3,5-isomers), thiophene, furan, thiazole, isothiazole, oxazole and isoxazole. The heteroaryl group may also be fused to an aromatic ring system, such as a benzene ring, to form members, including but not limited to benzopyrroles such as indole and isoindole, benzopyridines such as quinoline and isoquinoline, benzopyrazine (quinoxaline), benzopyrimidine (quinazoline), benzopyridazine such as phthalazine and cinnoline, benzothiophene and benzofuran. Other heteroaryl groups include heteroaryl rings linked by a bond, such as bipyridine. The heteroaryl group may be substituted or unsubstituted.

[0039] The heteroaryl group may be attached via any position on the ring. For example, pyrrole includes 1-, 2- and 3-pyrrole, pyridine includes 2-, 3- and 4-pyridine, imidazole includes 1-, 2-, 4- and 5-imidazole, pyrazole includes 1-, 3-, 4- and 5-pyrazole, triazole includes 1-, 4- and 5-triazole, tetrazole includes 1- and 5-tetrazole, pyrimidine includes 2-, 4-, 5- and 6-pyrimidine, pyridazine includes 3- and 4-pyridazine, 1,2,3-triazine includes 4- and 5-triazine, 1,2,4-triazine includes 3-, 5- and 6-triazine, 1,3,5-triazine includes 2-triazine, thiophene includes 2- and 3-thiophene, furan includes 2- and 3-furan, thiazole includes 2-, 4- and 5-thiazole, isothiazole includes 3-, 4- and 5-isothiazole, oxazole includes 2-, 4- and 5-oxazole, isoxazole includes 3-, 4- and 5-isoxazole, indole includes 1-, 2- and 3-indole, isoindole includes 1- and 2-isoindole, quinoline includes 2-, 3- and 4-quinoline, isoquinoline includes 1-, 3- and 4-isoquinoline, quinazoline includes 2- and 4-quinazoline, cinnoline includes 3- and 4-cinnoline, benzothiophene includes 2- and 3-benzothiophene, and benzofuran includes 2- and 3-benzofuran.

[0040] Some heteroaryl groups include those having 5 to 10 ring members and 1 to 3 ring atoms (including N, O, or S), such as pyrrole, pyridine, imidazole, pyrazole, triazole, pyrazine, pyrimidine, pyridazine, triazine (1,2,3-, 1,2,4-, and 1,3,5-isomers), thiophene, furan, thiazole, isothiazole, oxazole, isoxazole, indole, isoindole, quinoline, isoquinoline, quinoxaline, quinazoline, phthalazine, cinnoline, benzothiophene, and benzofuran. Other heteroaryl groups include those having 5 to 8 ring members and 1 to 3 heteroatoms, such as pyrrole, pyridine, imidazole, pyrazole, triazole, pyrazine, pyrimidine, pyridazine, triazine (1,2,3-, 1,2,4-, and 1,3,5-isomers), thiophene, furan, thiazole, isothiazole, oxazole, and isoxazole. Some other heteroaryl groups include those having 9 to 12 ring members and 1 to 3 heteroatoms, such as indole, isoindole, quinoline, isoquinoline, quinoxaline, quinazoline, phthalazine, cinnoline, benzothiophene, benzofuran, and bipyridine. Still other heteroaryl groups include those having 5 to 6 ring members and 1 to 2 ring atoms (including N, O, or S), such as pyrrole, pyridine, imidazole, pyrazole, pyrazine, pyrimidine, pyridazine, thiophene, furan, thiazole, isothiazole, oxazole, and isoxazole.

[0041] Some heteroaryl groups contain 5 to 10 ring members and only nitrogen heteroatoms, such as pyrrole, pyridine, imidazole, pyrazole, triazole, pyrazine, pyrimidine, pyridazine, triazine (1,2,3-, 1,2,4-, and 1,3,5-isomers), indole, isoindole, quinoline, isoquinoline, quinoxaline, quinazoline, phthalazine, and cinnoline. Other heteroaryl groups contain 5 to 10 ring members and only oxygen heteroatoms, such as furan and benzofuran. Some other heteroaryl groups contain 5 to 10 ring members and only sulfur heteroatoms, such as thiophene and benzothiophene. Still other heteroaryl groups contain 5 to 10 ring members and at least two heteroatoms, such as imidazole, pyrazole, triazole, pyrazine, pyrimidine, pyridazine, triazine (1,2,3-, 1,2,4-, and 1,3,5-isomers), thiazole, isothiazole, oxazole, isoxazole, quinoxaline, quinazoline, phthalazine, and cinnoline.

[0042] "Additive" refers to a component that makes up less than 10 mol% of the electrolyte, where the additive is added to the electrolyte to induce a mechanical effect different from that of the solvent or the salt containing the working ion. For example, an additive can be selected to preferentially decompose at the electrode surface to provide a preferred solid electrolyte interphase, bind or network the working ions or solvation clusters, bind or network the anions to increase the transference number, reduce the viscosity, or increase the conductivity.

[0043] "Conductivity" or "specific conductance" refers to the conductivity of an electrolyte solution, as measured in Siemens per meter (S / m or mS / cm).

[0044] "Dynamic viscosity" refers to a material property related to the viscous stress in a material in response to a strain rate, such as shear stress, measured in centipoise (cP) or equivalently millipascal-seconds (mPa·s).

[0045] "Electrochemical device" refers to a device in which an electric current is generated by a chemical reaction, where electrons are transferred directly between molecules and / or atoms in an oxidation-reduction reaction.

[0046] "Electrode" refers to a conductive material in an electrical circuit that contacts a non-metallic part of the circuit, such as an electrolyte. The electrode can be a positive electrode or cathode, i.e., the electrode where reduction occurs. The electrode can be a negative electrode or anode, i.e., the electrode where oxidation occurs.

[0047] "Separator" refers to an electrically insulating film between the positive electrode and the negative electrode to prevent electrical short circuit, i.e., to provide electron isolation. The separator also allows ions to move between the positive electrode and the anode. The separator can include any suitable electrically insulating polymeric or inorganic material. The separator can include several layers, the several layers including one or more membrane layers, and a porous support material for the membrane layer.

[0048] "First polymer layer" refers to a layer in the separator that is permeable to a first electrolyte species but substantially impermeable to the liquid electrolyte. The membrane layer can be any suitable material that can provide selective permeability, such as a composite of a microporous polymer and an inorganic material. "Substantially impermeable" means that less than 10% of the electrolyte solvent passes through the membrane layer, or less than 1%, or less than 0.1%, or less than 0.01%, or less than 0.001% of the liquid electrolyte passes through the membrane layer.

[0049] "Intrinsic microporosity polymer" refers to a polymer that exhibits microporosity due to the shape and rigidity of the molecular structure of the repeating units within the polymer, where the repeating units can be arranged relative to each other such that spaces or openings are created along the polymer chain. Additionally or alternatively, the repeating units can be arranged in aggregates of the polymer in a manner that obstructs the packing of polymer molecules within the aggregates, thereby creating spaces or openings between different polymer molecules and / or between segments of the same polymer molecule. These spaces within the aggregated polymer can provide at least partially the microporosity of such a polymer. Due to the inclusion of micropores, some intrinsic microporosity polymers may exhibit a high surface area, such as selected from 300 m 2 g -1 to 1500 m 2 g -1The surface area within a certain range. Example intrinsically microporous polymers include, but are not limited to, those described in U.S. Application Publication Nos. 2017 / 0346104 and 2018 / 0085744, U.S. Patent Nos. 7,690,514 and 8,056,732, and PCT Publication Nos. WO2005 / 012397 and WO 2005 / 113121, each of which is incorporated herein by reference.

[0050] "Oxide" refers to a chemical compound having oxygen, such as a metal oxide or a molecular oxide.

[0051] "Pore size" or "pore diameter" refers to the average diameter of the interstitial space not occupied by the pore-forming material. This can include, but is not limited to: the space remaining between polymer chains due to inefficient packing, the space remaining between organic linkers and metal ions in metal-organic frameworks, the space between layers and within pores of stacked 2D materials, and the space left in amorphous or semi-crystalline carbon due to misalignment of covalent bonds. The pore size may change or may remain unchanged after being wetted by an electrolyte.

[0052] "Surface area" refers to the surface area of a porous material measured by various methods, such as nitrogen adsorption BET.

[0053] "Microporous polymer" refers to an amorphous vitreous polymer having interconnected pores with an average diameter less than 10 nm, or less than 5 nm, 4 nm, 3 nm, 2 nm, or less than 1 nm.

[0054] "Microporosity" refers to a membrane layer containing pores with a size less than or equal to 2 nm.

[0055] As used herein, "intrinsic microporosity" refers to a continuous network of interconnected intermolecular voids (appropriately sized less than or equal to 2 nm) provided by a polymer, which forms as a direct result of the shape and rigidity of at least a proportion of the monomer components of the polymer. As will be understood by those skilled in the art, intrinsic microporosity results from the structure of the monomers used to form the polymer, and as the name implies, it is an inherent property of the polymer formed from such monomers.

[0056] It should be understood that the network polymers disclosed herein have certain properties (i.e., intrinsic microporosity). Certain structural requirements in the monomers for enabling the polymer to perform the disclosed functions are disclosed herein, and it should be understood that there are various structures related to the disclosed monomer structures that can perform the same function, and these structures will generally achieve the same result.

[0057] "Metal" refers to an element that is a metal in the periodic table of elements and that can be neutral, or negatively or positively charged due to having more or fewer electrons in its valence electron shell than the neutral metal element. Metals useful in the present invention include alkali metals, alkaline earth metals, transition metals, and post-transition metals. Alkali metals include Li, Na, K, Rb, and Cs. Alkaline earth metals include Be, Mg, Ca, Sr, and Ba. Transition metals include Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, and Ac. Post-transition metals include Al, Ga, In, Tl, Ge, Sn, Pb, Sb, Bi, and Po. Rare earth metals include Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Those skilled in the art will understand that the above metals can each exhibit several different oxidation states, and all of these oxidation states can be used in the present invention. In some cases, the most stable oxidation state is formed, but other oxidation states can also be used in the present invention.

[0058] "Porous support" refers to any suitable material that can support the film layer of the present invention and is permeable to the electrolyte.

[0059] "Laminating" refers to depositing one layer on another layer, such as depositing a microporous polymer layer or a first polymer layer onto a porous support.

[0060] "Mol%" refers to the mole percentage of a component based on the total number of moles in the composition.

[0061] III. Ternary Electrolyte

[0062] The electrolyte composition of the present invention comprises a primary solvent, a mediating solvent, a diluent, and a first lithium salt, wherein the primary solvent, the mediating solvent, and the diluent are each different. The solvents and components of the electrolyte composition of the present invention interact synergistically with each other in the electrolyte to improve the dynamic networking within the electrolyte when the battery pack is in use, and generally improve the conductivity and overall battery pack performance, thereby resulting in a more stable and durable high voltage and high density energy. Without wishing to be bound by theory, it is believed that due to the selected Li+ coordination strength of the three different solvents, the combination of the three different solvents and the lithium salt in the electrolyte of the present invention will retain the lithium salt-primary solvent clusters in the formulated electrolyte and result in a unique solvation structure of the lithium salt in the electrolyte.

[0063] The solvents of the electrolyte composition of the present invention are preferably miscible to avoid phase separation and form a clear and homogeneous electrolyte composition. The primary solvent, the mediating solvent, and the diluent in any given electrolyte composition can be characterized by having different Li +Coordination strength, such as the main solvent having the strongest Li + Coordination strength, the diluent having the weakest Li + Coordination strength, while the mediating solvent has Li between that of the main solvent and the diluent + Coordination strength + Coordination strength. Thus, a compound may be classified as a mediating solvent in one electrolyte composition but as a diluent in another electrolyte composition.

[0064] In some embodiments, the main solvent, the mediating solvent, and the diluent each have different Li + Coordination strength. In some embodiments, the Li + Coordination strength Ec (P) of the main solvent is greater than the Li + Coordination strength Ec (M) of the mediating solvent, and the Li + Coordination strength Ec (M) of the mediating solvent is greater than the Li + Coordination strength Ec (D) of the diluent:

[0065] Ec (P) > Ec (M) > Ec (D) .

[0066] In some embodiments, the present invention provides an electrolyte composition comprising: a main solvent; a mediating solvent; a diluent; and a first lithium salt, wherein the main solvent, the mediating solvent, and the diluent are each different.

[0067] Main solvent

[0068] The main solvent that can be used in the electrolyte composition of the present invention has a high Li + coordination strength and a relatively low molecular weight. Representative main solvents include, but are not limited to, ethers, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, cyclic ethers, and combinations thereof.

[0069] The ether of the present invention refers to a compound of the following formula:

[0070] R 1 -O-R 2 ,

[0071] wherein R 1 and R 2 are each independently C 1-6 alkyl, C 1-6 haloalkyl, C 3-8 cycloalkyl, heterocycloalkyl having 3 to 8 ring members and 1 to 3 heteroatoms each independently being N, O, or S, C 6-12An aryl or a heteroaryl having 5 to 8 ring members and 1 to 3 heteroatoms each independently being N, O or S. Alternatively, R 1 and R 2 may combine to form a cyclic ether, i.e., a heterocycloalkyl having 3 to 8 ring members and 0 to 3 additional heteroatoms each independently being O. Representative ethers include, but are not limited to, dimethyl ether, diethyl ether, oxirane, tetrahydrofuran, pyran and 1,4-dioxane. When one of R 1 and R 2 is a C 1-6 haloalkyl, a fluorinated ether can be formed.

[0072] The diglyme of the present invention refers to a compound of the following formula:

[0073] R 3 -O-(C 2-6 alkylene)-O-R 4 ,

[0074] wherein R 3 and R 4 are each independently a C 1-6 alkyl, a C 1-6 haloalkyl, a C 3-8 cycloalkyl, a heterocycloalkyl having 3 to 8 ring members and 1 to 3 heteroatoms each independently being N, O or S, a C 6-12 aryl or a heteroaryl having 5 to 8 ring members and 1 to 3 heteroatoms each independently being N, O or S; and the alkylene is substituted with 0 to 12 fluorine groups. Representative diglymes include, but are not limited to, monoglyme (1,2-dimethoxyethane), 1,2-diethoxyethane, diglyme (diethylene glycol dimethyl ether), triglyme (triethylene glycol dimethyl ether). When one of R 3 and R 4 is a C 1-6 haloalkyl or the C 2-6 alkylene is substituted with one or more fluorine groups, a fluorinated diglyme is formed.

[0075] The diglyme of the present invention refers to a compound of the following formula:

[0076] R 3 -[O-(C 2-6 alkylene)]2-O-R 4 ,

[0077] wherein R 3 and R 4 are each independently a C 1-6 alkyl, a C 1-6 haloalkyl, a C 3-8Cycloalkyl, heterocycloalkyl having 3 to 8 ring members and 1 to 3 heteroatoms each independently being N, O or S, C 6-12 Aryl or heteroaryl having 5 to 8 ring members and 1 to 3 heteroatoms each independently being N, O or S; and the alkylene group is substituted with 0 to 12 fluoro groups. Representative diglyme includes, but is not limited to, bis(2-methoxyethyl) ether. When R 3 and R 4 is one of C 1-6 haloalkyl, a fluorinated diglyme is formed. In some embodiments, each diglyme has the formula:

[0078] R 3 -[O-CH2CH2]2-O-R 4 .

[0079] In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent comprises an ether, a glyme, a cyclic ether, or a combination thereof. The primary solvent may have a calculated Li + coordination energy of less than -30, or less than -35, -40, -45 or less than -50.

[0080] In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent has the formula or a combination thereof

[0081] R 1 -O-R 2 ,

[0082] R 3 -O-(C 2-4 alkylene)-O-R 4 ,

[0083] wherein

[0084] R 1 and R 2 are each independently C 1-3 alkyl;

[0085] Alternatively, R 1 and R 2 can combine to form a heterocycloalkyl having 5 to 6 ring members and 0 to 2 additional heteroatoms each independently being O; and

[0086] R 3 and R 4 are each independently C 1-3 alkyl.

[0087] In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent comprises diethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,3-dioxolane, 1,4-dioxane, 1,3-dioxane, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent comprises diethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent comprises diethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent comprises 1,2-dimethoxyethane. In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent comprises 1,2-diethoxyethane.

[0088] The primary solvent can be present in the electrolyte composition in any suitable amount. For example, the primary solvent can be present in the electrolyte composition in an amount of 10 to 90 mol%, 10 to 80 mol%, 10 to 70 mol%, 20 to 70 mol%, 30 to 60 mol%, 35 to 55 mol%, 40 to 50 mol%, 45 to 50 mol%, 35 to 45 mol%, or 45 to 55 mol%. Representative amounts of the primary solvent in the electrolyte composition include, but are not limited to, about 35 mol%, or about 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, or about 55 mol%.

[0089] In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent is present in the electrolyte composition in an amount of 20 to 70 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent is present in the electrolyte composition in an amount of 30 to 60 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent is present in the electrolyte composition in an amount of 35 to 55 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent is present in the electrolyte composition in an amount of 35 to 50 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent is present in the electrolyte composition in an amount of 35 to 50 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent is present in the electrolyte composition in an amount of 35 to 45 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the primary solvent is present in the electrolyte composition in an amount of 45 to 50 mol%.

[0090] The electrolyte composition of the present invention may comprise one or more primary solvents. For example, the electrolyte composition may comprise 1, 2, 3, 4 or more different primary solvents as defined above. In some embodiments, the electrolyte composition is an electrolyte composition comprising one primary solvent. In some embodiments, the electrolyte composition is an electrolyte composition comprising two different primary solvents. In some embodiments, the electrolyte composition is an electrolyte composition comprising three different primary solvents.

[0091] Mediating solvent

[0092] The mediating solvents useful in the electrolyte compositions of the present invention have low to medium Li + coordination strength and are substantially miscible with the primary solvent and the diluent. Representative mediating solvents include, but are not limited to, fluorinated ethers, fluorinated diglyme, fluorinated cyclic ethers, or combinations thereof, wherein the ethers, diglyme, and cyclic ethers are as defined above. The fluorinated mediating solvent may be fully or partially fluorinated.

[0093] In some embodiments, the electrolyte composition is an electrolyte composition wherein the mediating solvent comprises a fluorinated ether, a fluorinated diglyme, a fluorinated cyclic ether, or a combination thereof. The mediating solvent may have a calculated Li + coordination energy of -10 to -50, -15 to -45, -20 to -40, or -30 to -40.

[0094] In some embodiments, the electrolyte composition is an electrolyte composition wherein the mediating solvent has the following formula or a combination thereof:

[0095] R 1 -O-R 2 ,

[0096] R 3 -O-(C 2-4 alkylene)-O-R 4 ,

[0097] wherein

[0098] R 1 and R 2 are each independently C 1-6 haloalkyl;

[0099] R 3 and R 4 are each independently C 1-6 alkyl or C 1-6 haloalkyl; and

[0100] the alkylene is substituted with 0 to 8 fluoro groups,

[0101] wherein R 3 and R4 at least one of which is C 1-6 haloalkyl, or the alkylene group is substituted with 1 to 8 fluoro groups.

[0102] In some embodiments, the electrolyte composition is an electrolyte composition in which the mediating solvent comprises 2,2,3,3-tetrafluoro-1,4-dimethoxybutane, 2-(2-ethoxyethoxy)-1,1,1-trifluoroethane, 1,2-bis(2,2-difluoroethoxy)ethane, 1,2-bis(2,2,2-trifluoroethoxy)ethane, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the mediating solvent comprises 2,2,3,3-tetrafluoro-1,4-dimethoxybutane, 1,2-bis(2,2-difluoroethoxy)ethane, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the mediating solvent comprises 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the mediating solvent comprises 2,2,3,3-tetrafluoro-1,4-dimethoxybutane, 1,2-bis(2,2-difluoroethoxy)ethane, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the mediating solvent comprises 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether. In some embodiments, the electrolyte composition is an electrolyte composition in which the mediating solvent comprises 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane.

[0103] In some embodiments, the mediating solvent of the present invention may have the following formula:

[0104] R 3 -O-CH2CH2-O-R 4 ,

[0105] wherein R 3 and R 4 are each independently C 1-6 alkyl or C 1-6 haloalkyl. In some embodiments, the electrolyte composition comprises wherein R 3 and R4 Each independently is C 2-4 alkyl or C 2-4 a mediating solvent that is haloalkyl. In some embodiments, the electrolyte composition comprises a mediating solvent in which R 3 and R 4 are each independently C2 alkyl or C2 haloalkyl. In some embodiments, the electrolyte composition comprises a mediating solvent in which R 3 and R 4 are each independently C2 haloalkyl.

[0106] In some embodiments, the electrolyte composition comprises a mediating solvent in which R 3 and R 4 are each independently ethyl, 1-fluoroethyl, 1,1-difluoroethyl, 1,1,1-trifluoroethyl, 1,2-difluoroethyl, 1,1,2-trifluoroethyl, 1,1,1,2-tetrafluoroethyl, 1,2,2-trifluoroethyl, 1,1,2,2-tetrafluoroethyl or 1,1,1,2,2-pentafluoroethyl. In some embodiments, the electrolyte composition comprises a mediating solvent in which R 3 and R 4 are different.

[0107] In some embodiments, the electrolyte composition is one in which the mediating solvent comprises 1-(2-ethoxyethoxy)-2-fluoroethane, 1-(2-ethoxyethoxy)-2,2-difluoroethane, 1-(2-ethoxyethoxy)-2,2,2-trifluoroethane, 1-(2-ethoxyethoxy)-1,2-difluoroethane, 1-(2-ethoxyethoxy)-1,2,2-trifluoroethane, 1-(2-ethoxyethoxy)-1,2,2,2-tetrafluoroethane, 1-(2-ethoxyethoxy)-1,1,2-trifluoroethane, 1-(2-ethoxyethoxy)-1,1,2,2-tetrafluoroethane or 1-(2-ethoxyethoxy)-1,1,2,2,2-pentafluoroethane.

[0108] In some embodiments, the electrolyte composition is an electrolyte composition in which the mediating solvent comprises 1,2-bis(2-fluoroethoxy)ethane, 1,1-difluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane, 1,1,1-trifluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane, 1,2-difluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane, 1,1,2-trifluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane, 1,1,1,2-tetrafluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane, 1,2,2-trifluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane, 1,1,2,2-tetrafluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane or 1,1,1,2,2-pentafluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane.

[0109] In some embodiments, the electrolyte composition is an electrolyte composition in which the mediating solvent comprises 1,2-bis(2,2-difluoroethoxy)ethane, 1,1,1-trifluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane, 1,2-difluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane, 1,1,2-trifluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane, 1,1,1,2-tetrafluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane, 1,2,2-trifluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane, 1,1,2,2-tetrafluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane or 1,1,1,2,2-pentafluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane.

[0110] In some embodiments, the electrolyte composition is an electrolyte composition in which the mediating solvent comprises 1,2-bis(2,2,2-trifluoroethoxy)ethane, 1,2-difluoro-2-(2-(2,2,2-trifluoroethoxy)ethoxy)ethane, 1,1,2-trifluoro-2-(2-(2,2,2-trifluoroethoxy)ethoxy)ethane, 1,1,1,2-tetrafluoro-2-(2-(2,2,2-trifluoroethoxy)ethoxy)ethane, 1,2,2-trifluoro-2-(2-(2,2,2-trifluoroethoxy)ethoxy)ethane, 1,1,2,2-tetrafluoro-2-(2-(2,2,2-trifluoroethoxy)ethoxy)ethane or 1,1,1,2,2-pentafluoro-2-(2-(2,2,2-trifluoroethoxy)ethoxy)ethane.

[0111] The mediating solvent can be present in the electrolyte composition in any suitable amount. For example, the mediating solvent can be present in the electrolyte composition in an amount of 1 to 50 mol%, 1 to 40 mol%, 1 to 30 mol%, 5 to 25 mol%, 5 to 20 mol%, 10 to 20 mol%, 10 to 15 mol%, 15 to 20 mol%, 5 to 15 mol%, or 5 to 10 mol%. Representative amounts of the mediating solvent in the electrolyte composition include, but are not limited to, about 5 mol%, or about 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or about 25 mol%.

[0112] In some embodiments, the electrolyte composition is an electrolyte composition in which the mediating solvent is present in the electrolyte composition in an amount of 1 to 30 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the mediating solvent is present in the electrolyte composition in an amount of 5 to 20 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in an amount of 10 to 20 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in an amount of 5 to 10 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in an amount of 15 to 20 mol%.

[0113] The electrolyte composition of the present invention can include one or more mediating solvents. For example, the electrolyte composition can include 1, 2, 3, 4 or more different mediating solvents as defined above. In some embodiments, the electrolyte composition is an electrolyte composition comprising one mediating solvent. In some embodiments, the electrolyte composition is an electrolyte composition comprising two different mediating solvents. In some embodiments, the electrolyte composition is an electrolyte composition comprising three different mediating solvents.

[0114] Diluent

[0115] The diluent that can be used in the electrolyte composition of the present invention has a relatively low Li + coordination strength compared to the primary solvent and the mediating solvent, thereby allowing the primary solvent to occupy the first solvation shell of Li + . Representative diluents include, but are not limited to, fluorinated ethers, fluorinated diglyme, cyclic ethers, fluorinated cyclic ethers, or combinations thereof, wherein the ethers, diglyme, and cyclic ethers are as defined above. The fluorinated diluent can be fully or partially fluorinated.

[0116] In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent comprises a fluorinated ether, a fluorinated glycol dimethyl ether, a cyclic ether, a fluorinated cyclic ether, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent is a fluorinated ether, a fluorinated glycol dimethyl ether, a cyclic ether, a fluorinated cyclic ether, or a combination thereof. The diluent may have a calculated Li + coordination energy of from -10 to -50, -15 to -45, -20 to -40, or -25 to -35.

[0117] In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent has the following formula or a combination thereof:

[0118] R 1 -O-R 2 ,

[0119] R 3 -O-(C 2-4 alkylene)-O-R 4 ,

[0120] wherein

[0121] R 1 and R 2 are each independently C 1-6 haloalkyl;

[0122] Alternatively, R 1 and R 2 may combine to form a heterocycloalkyl having 5 to 6 ring members and 0 to 3 additional heteroatoms each independently being O;

[0123] R 3 and R 4 are each independently C 1-6 alkyl or C 1-6 haloalkyl; and

[0124] the alkylene is substituted with 0 to 8 fluoro groups,

[0125] wherein at least one of R 3 and R 4 is C 1-6 haloalkyl, or the alkylene is substituted with 1 to 8 fluoro groups.

[0126] In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent comprises 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent is 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent comprises 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent is 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent comprises 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether.

[0127] In some embodiments, the diluent of the present invention may have the following formula:

[0128] R 3 -O-CH2CH2-O-R 4 ,

[0129] wherein R 3 and R 4 are each independently a C 1-6 alkyl or a C 1-6 haloalkyl. In some embodiments, the electrolyte composition comprises a diluent in which R 3 and R 4 are each independently a C 2-4 alkyl or a C 2-4 haloalkyl. In some embodiments, the electrolyte composition comprises a diluent in which R 3 and R 4 are each independently a C2 alkyl or a C2 haloalkyl. In some embodiments, the electrolyte composition comprises a diluent in which R 3 and R 4 are each independently a C2 haloalkyl.

[0130] In some embodiments, the electrolyte composition comprises a diluent in which R 3 and R 4A diluent that is independently selected from ethyl, 1-fluoroethyl, 1,1-difluoroethyl, 1,1,1-trifluoroethyl, 1,2-difluoroethyl, 1,1,2-trifluoroethyl, 1,1,1,2-tetrafluoroethyl, 1,2,2-trifluoroethyl, 1,1,2,2-tetrafluoroethyl or 1,1,1,2,2-pentafluoroethyl. In some embodiments, the electrolyte composition comprises a diluent wherein R 3 and R 4 are different diluents.

[0131] In some embodiments, the electrolyte composition is an electrolyte composition wherein the diluent comprises 1-(2-ethoxyethoxy)-2-fluoroethane, 1-(2-ethoxyethoxy)-2,2-difluoroethane, 1-(2-ethoxyethoxy)-2,2,2-trifluoroethane, 1-(2-ethoxyethoxy)-1,2-difluoroethane, 1-(2-ethoxyethoxy)-1,2,2-trifluoroethane, 1-(2-ethoxyethoxy)-1,2,2,2-tetrafluoroethane, 1-(2-ethoxyethoxy)-1,1,2-trifluoroethane, 1-(2-ethoxyethoxy)-1,1,2,2-tetrafluoroethane or 1-(2-ethoxyethoxy)-1,1,2,2,2-pentafluoroethane.

[0132] In some embodiments, the electrolyte composition is an electrolyte composition wherein the diluent comprises 1,2-bis(2-fluoroethoxy)ethane, 1,1-difluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane, 1,1,1-trifluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane, 1,2-difluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane, 1,1,2-trifluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane, 1,1,1,2-tetrafluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane, 1,2,2-trifluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane, 1,1,2,2-tetrafluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane or 1,1,1,2,2-pentafluoro-2-(2-(2-fluoroethoxy)ethoxy)ethane.

[0133] In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent comprises 1,2-bis(2,2-difluoroethoxy)ethane, 1,1,1-trifluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane, 1,2-difluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane, 1,1,2-trifluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane, 1,1,1,2-tetrafluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane, 1,2,2-trifluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane, 1,1,2,2-tetrafluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane or 1,1,1,2,2-pentafluoro-2-(2-(2,2-difluoroethoxy)ethoxy)ethane.

[0134] In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent comprises 1,2-bis(2,2,2-trifluoroethoxy)ethane, 1,2-difluoro-2-(2-(2,2,2-trifluoroethoxy)ethoxy)ethane, 1,1,2-trifluoro-2-(2-(2,2,2-trifluoroethoxy)ethoxy)ethane, 1,1,1,2-tetrafluoro-2-(2-(2,2,2-trifluoroethoxy)ethoxy)ethane, 1,2,2-trifluoro-2-(2-(2,2,2-trifluoroethoxy)ethoxy)ethane, 1,1,2,2-tetrafluoro-2-(2-(2,2,2-trifluoroethoxy)ethoxy)ethane or 1,1,1,2,2-pentafluoro-2-(2-(2,2,2-trifluoroethoxy)ethoxy)ethane.

[0135] The diluent can be present in the electrolyte composition in any suitable amount. For example, the diluent can be present in the electrolyte composition in an amount of 1 to 50 mol%, 1 to 40 mol%, 1 to 30 mol%, 5 to 25 mol%, 5 to 20 mol%, 10 to 20 mol%, 10 to 15 mol% or 15 to 20 mol%. Representative amounts of the diluent in the electrolyte composition include, but are not limited to, about 5 mol%, or about 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 mol%.

[0136] In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent is present in the electrolyte composition in an amount of 1 to 30 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent is present in the electrolyte composition in an amount of 5 to 20 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent is present in an amount of 5 to 15 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the diluent is present in an amount of 9 to 14 mol%.

[0137] The electrolyte composition of the present invention may include one or more diluents. For example, the electrolyte composition may include 1, 2, 3, 4 or more different diluents as defined above. In some embodiments, the electrolyte composition is an electrolyte composition containing a single diluent. In some embodiments, the electrolyte composition is an electrolyte composition containing two different diluents. In some embodiments, the electrolyte composition is an electrolyte composition containing three different diluents.

[0138] Lithium salt

[0139] The lithium salt of the electrolyte composition of the present invention can be any suitable lithium salt. For example, suitable lithium salts include but are not limited to lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium 4,5-dicyano-2-(trifluoromethyl)imidazolium, lithium difluoro(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, lithium nitrate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, or combinations thereof. In some embodiments, the lithium salt can be lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium 4,5-dicyano-2-(trifluoromethyl)imidazolium, lithium difluoro(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, lithium nitrate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, or combinations thereof.

[0140] In some embodiments, the electrolyte composition is an electrolyte composition in which the first lithium salt includes lithium bis(fluorosulfonyl)imide (LiFSi), lithium hexafluorophosphate, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the first lithium salt includes lithium bis(fluorosulfonyl)imide (LiFSi).

[0141] The first lithium salt can be present in the electrolyte composition in any suitable amount. For example, the first lithium salt can be present in the electrolyte composition in an amount of 1 to 50 mol%, 5 to 50 mol%, 10 to 50 mol%, 15 to 45 mol%, 20 to 40 mol%, 25 to 35 mol%, or 25 to 30 mol%. Representative amounts of the first lithium salt in the electrolyte composition of the present invention include but are not limited to about 20 mol%, or about 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or about 35 mol%.

[0142] In some embodiments, the electrolyte composition is an electrolyte composition in which the first lithium salt is present in the electrolyte composition in an amount of 10 to 50 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the first lithium salt is present in the electrolyte composition in an amount of 20 to 40 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the first lithium salt is present in the electrolyte composition in an amount of 25 to 35 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the first lithium salt is present in the electrolyte composition in an amount of 25 to 30 mol%.

[0143] The first lithium salt can be present in the electrolyte composition of the present invention at any suitable ratio to the main solvent. For example, the molar ratio of the main solvent to the first lithium salt in the electrolyte composition of the present invention can be 10:1 to 1:1, 5:1 to 1.1:1, 4.5:1 to 1.2:1, 4:1 to 1.3:1, 3.5:1 to 1.4:1, 3:1 to 1.4:1, 2.5:1 to 1.4:1, or 2:1 to 1.4:1. Representative molar ratios of the main solvent to the first lithium salt in the electrolyte composition of the present invention can be about 2:1, or about 1.9:1, 1.8:1, 1.7:1, 1.6:1, 1.5:1, 1.4:1, 1.3:1, 1.2:1, 1.1:1, or about 1:1.

[0144] In some embodiments, the electrolyte composition is an electrolyte composition in which the molar ratio of the main solvent to the first lithium salt is 3.5:1 to 1.4:1. In some embodiments, the electrolyte composition is an electrolyte composition in which the molar ratio of the main solvent to the first lithium salt is 2.0:1 to 1.4:1.

[0145] The electrolyte composition of the present invention can comprise one or more lithium salts. For example, the electrolyte composition can comprise 1, 2, 3, 4 or more different lithium salts as defined above. In some embodiments, the electrolyte composition is an electrolyte composition comprising a single lithium salt. In some embodiments, the electrolyte composition is an electrolyte composition comprising two different lithium salts. In some embodiments, the electrolyte composition is an electrolyte composition comprising three different lithium salts.

[0146] The electrolyte composition of the present invention can further comprise a second lithium salt different from the first lithium salt. In some embodiments, the electrolyte composition is an electrolyte composition comprising a second lithium salt different from the first lithium salt.

[0147] In some embodiments, the electrolyte composition is an electrolyte composition in which the second lithium salt comprises lithium 4,5-dicyano-2-(trifluoromethyl)imidazolium, lithium difluoro(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, lithium nitrate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the second lithium salt comprises lithium 4,5-dicyano-2-(trifluoromethyl)imidazolium, lithium difluoro(oxalato)borate, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the second lithium salt comprises lithium 4,5-dicyano-2-(trifluoromethyl)imidazolium. In some embodiments, the electrolyte composition is an electrolyte composition in which the second lithium salt comprises lithium difluoro(oxalato)borate. In some embodiments, the electrolyte composition is an electrolyte composition in which the second lithium salt comprises lithium nitrate.

[0148] The second lithium salt can be present in the electrolyte composition in any suitable amount. For example, the second lithium salt can be present in the electrolyte composition in an amount of 0.1 to 10 mol%, 0.1 to 5 mol%, 0.5 to 5 mol%, 0.5 to 4 mol%, 0.5 to 3.5 mol%, 1 to 3 mol%, 1.0 to 2.5 mol%, or 1.5 to 2.5 mol%. Representative amounts of the second lithium salt in the electrolyte composition of the present invention include, but are not limited to, about 1.5 mol%, or about 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, or about 2.5 mol%.

[0149] In some embodiments, the electrolyte composition is an electrolyte composition in which the second lithium salt is present in the electrolyte composition in an amount of 0.1 to 5 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the second lithium salt is present in the electrolyte composition in an amount of 0.5 to 3.5 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the second lithium salt is present in the electrolyte composition in an amount of 1 to 3 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the second lithium salt is present in the electrolyte composition in an amount of 1.5 to 2.5 mol%.

[0150] Additive

[0151] The electrolyte composition of the present invention may further comprise an additive. In some embodiments, the electrolyte composition is an electrolyte composition comprising an additive. The electrolyte composition of the present invention may further comprise an additive. In some embodiments, the electrolyte composition is an electrolyte composition comprising an additive. Without being bound by any particular theory, the additive may be selected to preferentially decompose via reduction at the anode surface to provide a preferred solid electrolyte interphase. Such an additive may have a LUMO energy of less than 0.5 eV. Alternatively, the additive may be selected to preferentially decompose via oxidation at the cathode surface to provide a preferred cathode electrolyte interphase. Such an additive may have a HOMO energy greater than [-7.5 eV] or an oxidation potential less than [6.5 V]. The additive may also be selected to decompose both at the anode and at the cathode, thereby providing both a preferred solid electrolyte interphase and a preferred cathode electrolyte interphase. Alternatively, the additive may be selected to bind or network working ions or solvation clusters. The additive may also be selected to preferentially bind anions at Lewis acidic sites, where the electrostatic potential is substantially positive. When the additive is a Lewis acid additive, the additive may be selected to bind or network anions to increase the transference number. In some embodiments, the additive is selected to reduce the viscosity. In some embodiments, the additive is selected to increase the conductivity. Those of ordinary skill in the art will understand that these mechanisms are orthogonal and thus a single additive may be selected to provide several mechanisms to improve the electrolyte performance. Alternatively, several additives may be included in the electrolyte composition to provide the same or different mechanisms to improve the electrolyte performance.

[0152] Without being bound by any particular theory, the additive may be selected to preferentially decompose at the anode surface, at the cathode surface, or at both the anode surface and the cathode surface, thereby providing a preferred solid electrolyte interphase, binding or networking working ions or solvation clusters, and binding or networking anions to increase the transference number. In some embodiments, the additive is selected to reduce the viscosity. In some embodiments, the additive is selected to increase the conductivity.

[0153] In some embodiments, the electrolyte composition is an electrolyte composition in which the additive comprises 1,3,2-dioxathiane 2,2-dioxide, 1,3,2-dioxolane 2,2-dioxide, 2-fluoropyridine, bis(trimethylsilyl) malonate, dimethylacetamide, phenyltrifluorosilane, ethoxy(pentafluoro)phosphazene, fluoroethylene carbonate, p-tolylsulfur pentafluoride, succinonitrile, tetrafluoroterephthalonitrile, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, tris(trimethylsilyl) phosphate, or a combination thereof. In some embodiments, the electrolyte composition is an electrolyte composition in which the additive comprises 1,3,2-dioxathiane 2,2-dioxide. In some embodiments, the electrolyte composition is an electrolyte composition in which the additive comprises 1,3,2-dioxolane 2,2-dioxide. In some embodiments, the electrolyte composition is an electrolyte composition in which the additive comprises ethoxy(pentafluoro)phosphazene. In some embodiments, the electrolyte composition is an electrolyte composition in which the additive comprises tris(trimethylsilyl) phosphate.

[0154] The additive can be present in the electrolyte composition of the present invention in any suitable amount. For example, the additive can be present in the electrolyte composition of the present invention in an amount of 0.1 to 10 mol%, 0.1 to 5 mol%, 0.1 to 4 mol%, 0.1 to 3 mol%, 0.5 to 3 mol%, 0.1 to 2.5 mol%, 0.5 to 2.5 mol%, 0.8 to 2.5 mol%, 0.1 to 2 mol%, or 0.5 to 1.5 mol%. Representative amounts of the additive in the electrolyte composition of the present invention include, but are not limited to, about 0.3 mol%, or about 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, or about 1.5 mol%.

[0155] In some embodiments, the electrolyte composition is an electrolyte composition in which the additive is present in the electrolyte composition in an amount of 0.1 to 5 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the additive is present in the electrolyte composition in an amount of 0.5 to 3 mol%. In some embodiments, the electrolyte composition is an electrolyte composition in which the additive is present in the electrolyte composition in an amount of 0.8 to 2.5 mol%.

[0156] The electrolyte composition of the present invention may comprise one or more additives. For example, the electrolyte composition may comprise 1, 2, 3, 4 or more different additives as defined above. In some embodiments, the electrolyte composition is an electrolyte composition comprising a single additive. In some embodiments, the electrolyte composition is an electrolyte composition comprising two different additives. In some embodiments, the electrolyte composition is an electrolyte composition comprising three different additives.

[0157] Electrolyte composition

[0158] In some embodiments, the electrolyte composition is an electrolyte composition comprising the following:

[0159] The primary solvent is an ether, diglyme, cyclic ether or a combination thereof;

[0160] The mediating solvent is a fluorinated ether, fluorinated diglyme, fluorinated cyclic ether or a combination thereof;

[0161] The diluent is a fluorinated ether, fluorinated diglyme, cyclic ether, fluorinated cyclic ether or a combination thereof; and

[0162] A first lithium salt.

[0163] In some embodiments, the electrolyte composition is an electrolyte composition comprising the following:

[0164] The primary solvent in an amount of 20 to 70 mol%;

[0165] The mediating solvent in an amount of 1 to 30 mol%;

[0166] The diluent in an amount of 1 to 30 mol%; and

[0167] The first lithium salt in an amount of 10 to 50 mol%.

[0168] In some embodiments, the electrolyte composition is an electrolyte composition comprising the following:

[0169] The primary solvent is an ether, diglyme, cyclic ether or a combination thereof, wherein the primary solvent is present in an amount of 20 to 70 mol%;

[0170] The mediating solvent is a fluorinated ether, fluorinated diglyme, fluorinated cyclic ether or a combination thereof, wherein the mediating solvent is present in an amount of 1 to 30 mol%;

[0171] The diluent is a fluorinated ether, fluorinated diglyme, cyclic ether, fluorinated cyclic ether or a combination thereof, wherein the diluent is present in an amount of 1 to 30 mol%; and

[0172] The first lithium salt in an amount of 10 to 50 mol%.

[0173] In some embodiments, the electrolyte composition is an electrolyte composition comprising:

[0174] The primary solvent is diethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,3-dioxolane, 1,4-dioxane, 1,3-dioxane, or a combination thereof;

[0175] The mediating solvent is 2,2,3,3-tetrafluoro-1,4-dimethoxybutane, 1,2-bis(2,2-difluoroethoxy)ethane, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane, or a combination thereof;

[0176] The diluent is 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, or a combination thereof; and

[0177] The first lithium salt is lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium 4,5-dicyano-2-(trifluoromethyl)imidazolium, lithium difluoro(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, lithium nitrate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, or a combination thereof.

[0178] In some embodiments, the electrolyte composition is an electrolyte composition comprising:

[0179] The primary solvent is diethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,3-dioxolane, 1,4-dioxane, 1,3-dioxane, or a combination thereof, wherein the primary solvent is present in an amount of 20 to 70 mol%;

[0180] The mediating solvent is 2,2,3,3-tetrafluoro-1,4-dimethoxybutane, 1,2-bis(2,2-difluoroethoxy)ethane, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane, or a combination thereof, wherein the mediating solvent is present in an amount of 1 to 30 mol%;

[0181] The diluent is 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, or a combination thereof, wherein the diluent is present in an amount of 1 to 30 mol%; and

[0182] The first lithium salt is lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, 4,5-dicyano-2-(trifluoromethyl)imidazolium lithium, lithium difluoro(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, lithium nitrate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, or a combination thereof, wherein the first lithium salt is present in an amount of 10 to 50 mol%.

[0183] In some embodiments, the electrolyte composition is an electrolyte composition consisting essentially of: a primary solvent; a mediating solvent; a diluent; a first lithium salt; optionally a second lithium salt; and optionally an additive. In some embodiments, the electrolyte composition is an electrolyte composition consisting of: a primary solvent; a mediating solvent; a diluent; a first lithium salt; optionally a second lithium salt; and optionally an additive.

[0184] In some embodiments, the electrolyte composition is an electrolyte composition comprising: a primary solvent; a mediating solvent; a diluent; a first lithium salt; a second lithium salt; and an additive.

[0185] In some embodiments, the electrolyte composition is an electrolyte composition comprising:

[0186] The primary solvent is diethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,3-dioxolane, 1,4-dioxane, 1,3-dioxane, or a combination thereof;

[0187] The mediating solvent is 2,2,3,3-tetrafluoro-1,4-dimethoxybutane, 1,2-bis(2,2-difluoroethoxy)ethane, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane, or a combination thereof;

[0188] The diluent is 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, or a combination thereof;

[0189] The first lithium salt is lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, 4,5-dicyano-2-(trifluoromethyl)imidazolium lithium, lithium difluoro(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, lithium nitrate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, or a combination thereof;

[0190] The second lithium salt is 4,5-dicyano-2-(trifluoromethyl)imidazolium lithium, lithium difluoro(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, lithium nitrate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, or a combination thereof; and

[0191] The additives are 1,3,2-dioxathiane 2,2-dioxide, 1,3,2-dioxolane 2,2-dioxide, 2-fluoropyridine, bis(trifluoromethylsilyl) malonate, dimethylacetamide, phenyltrifluorosilane, ethoxy(pentafluoro)phosphazene, fluoroethylene carbonate, p-tolylsulfur pentafluoride, succinonitrile, tetrafluoroterephthalonitrile, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, tris(trimethylsilyl) phosphate, or a combination thereof.

[0192] In some embodiments, the electrolyte composition is an electrolyte composition comprising:

[0193] a primary solvent in an amount of 20 to 70 mol%;

[0194] a mediating solvent in an amount of 1 to 30 mol%;

[0195] a diluent in an amount of 1 to 30 mol%;

[0196] a first lithium salt in an amount of 10 to 50 mol%;

[0197] a second lithium salt in an amount of 0.1 to 5 mol%; and

[0198] an additive in an amount of 0.1 to 5 mol%.

[0199] In some embodiments, the electrolyte composition is an electrolyte composition comprising:

[0200] The primary solvent is diethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,3-dioxolane, 1,4-dioxane, 1,3-dioxane, or a combination thereof, wherein the primary solvent is present in an amount of 20 to 70 mol%;

[0201] The mediating solvent is 2,2,3,3-tetrafluoro-1,4-dimethoxybutane, 1,2-bis(2,2-difluoroethoxy)ethane, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane, or a combination thereof, wherein the mediating solvent is present in an amount of 1 to 30 mol%;

[0202] The diluent is 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, or a combination thereof, wherein the diluent is present in an amount of 1 to 30 mol%;

[0203] The first lithium salt is lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, 4,5-dicyano-2-(trifluoromethyl)imidazolium lithium, lithium difluoro(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, lithium nitrate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, or a combination thereof, wherein the first lithium salt is present in an amount of 10 to 50 mol%;

[0204] The second lithium salt is 4,5-dicyano-2-(trifluoromethyl)imidazolium lithium, lithium difluoro(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, lithium nitrate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, or a combination thereof, wherein the second lithium salt is present in an amount of 0.1 to 5 mol%; and

[0205] The additive is 1,3,2-dioxathiolane 2,2-dioxide, 1,3,2-dioxolane 2,2-dioxide, 2-fluoropyridine, bis(trifluoromethylsilyl) malonate, dimethylacetamide, phenyltrifluorosilane, ethoxy(pentafluoro)phosphazene, fluoroethylene carbonate, p-tolylsulfur pentafluoride, succinonitrile, tetrafluoroterephthalonitrile, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, tris(trimethylsilyl) phosphate, or a combination thereof, wherein the additive is present in an amount of 0.1 to 5 mol%.

[0206] In some embodiments, the electrolyte composition is an electrolyte composition comprising:

[0207] a primary solvent in an amount of 35 to 50 mol%;

[0208] a mediating solvent in an amount of 5 to 20 mol%;

[0209] a diluent in an amount of 5 to 20 mol%; and

[0210] a first lithium salt in an amount of 25 to 35 mol%.

[0211] In some embodiments, the electrolyte composition is an electrolyte composition comprising:

[0212] The primary solvent is diethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,3-dioxolane, 1,4-dioxane, 1,3-dioxane, or a combination thereof, wherein the primary solvent is present in an amount of 35 to 50 mol%;

[0213] The mediating solvent is 2,2,3,3 - tetrafluoro - 1,4 - dimethoxybutane, 1,2 - bis(2,2 - difluoroethoxy)ethane, 1H,1H,5H - octafluoropentyl 1,1,2,2 - tetrafluoroethyl ether, 2-(2-(2,2 - difluoroethoxy)ethoxy)-1,1,1 - trifluoroethane or a combination thereof, wherein the mediating solvent is present in an amount of 5 to 20 mol%;

[0214] The diluent is 1,1,2,2 - tetrafluoroethyl 2,2,3,3 - tetrafluoropropyl ether, 1H,1H,5H - octafluoropentyl 1,1,2,2 - tetrafluoroethyl ether or a combination thereof, wherein the diluent is present in an amount of 5 to 20 mol%; and

[0215] The first lithium salt is lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, 4,5 - dicyano - 2-(trifluoromethyl)imidazolium lithium, lithium difluoro(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, lithium nitrate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate or a combination thereof, wherein the first lithium salt is present in an amount of 25 to 35 mol%.

[0216] In some embodiments, the electrolyte composition is an electrolyte composition comprising:

[0217] A primary solvent in an amount of 35 to 50 mol%;

[0218] A mediating solvent in an amount of 5 to 20 mol%;

[0219] A diluent in an amount of 5 to 20 mol%;

[0220] A first lithium salt in an amount of 25 to 35 mol%;

[0221] A second lithium salt in an amount of 1.5 to 2.5 mol%; and

[0222] An additive in an amount of 0.8 to 2.5 mol%.

[0223] In some embodiments, the electrolyte composition is an electrolyte composition comprising:

[0224] The primary solvent is diethyl ether, 1,2 - dimethoxyethane, 1,2 - diethoxyethane, 1,3 - dioxolane, 1,4 - dioxane, 1,3 - dioxane or a combination thereof, wherein the primary solvent is present in an amount of 35 to 50 mol%;

[0225] The mediating solvent is 2,2,3,3 - tetrafluoro - 1,4 - dimethoxybutane, 1,2 - bis(2,2 - difluoroethoxy)ethane, 1H,1H,5H - octafluoropentyl 1,1,2,2 - tetrafluoroethyl ether, 2 - (2 - (2,2 - difluoroethoxy)ethoxy)-1,1,1 - trifluoroethane, or a combination thereof, wherein the mediating solvent is present in an amount of 5 to 20 mol%;

[0226] The diluent is 1,1,2,2 - tetrafluoroethyl 2,2,3,3 - tetrafluoropropyl ether, 1H,1H,5H - octafluoropentyl 1,1,2,2 - tetrafluoroethyl ether, or a combination thereof, wherein the diluent is present in an amount of 5 to 20 mol%;

[0227] The first lithium salt is lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, 4,5 - dicyano - 2 - (trifluoromethyl)imidazolium lithium, lithium difluoro(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, lithium nitrate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, or a combination thereof, wherein the first lithium salt is present in an amount of 25 to 35 mol%;

[0228] The second lithium salt is 4,5 - dicyano - 2 - (trifluoromethyl)imidazolium lithium, lithium difluoro(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, lithium nitrate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, or a combination thereof, wherein the second lithium salt is present in an amount of 1.5 to 2.5 mol%; and

[0229] The additive is 1,3,2 - dioxathiane 2,2 - dioxide, 1,3,2 - dioxolane 2,2 - dioxide, 2 - fluoropyridine, bis(trifluoromethylsilyl) malonate, dimethylacetamide, phenyltrifluorosilane, ethoxy(pentafluoro)phosphazene, fluoroethylene carbonate, p - tolylpentafluorosulfide, succinonitrile, tetrafluoroterephthalonitrile, 2,4 - tolylene diisocyanate, 2,6 - tolylene diisocyanate, tris(trimethylsilyl) phosphate, or a combination thereof, wherein the additive is present in an amount of 0.8 to 2.5 mol%.

[0230] In some embodiments, the electrolyte composition is an electrolyte composition wherein:

[0231] The main solvent comprises 1,2 - dimethoxyethane;

[0232] The mediating solvent is 1H,1H,5H - octafluoropentyl 1,1,2,2 - tetrafluoroethyl ether or 2 - (2 - (2,2 - difluoroethoxy)ethoxy)-1,1,1 - trifluoroethane;

[0233] The diluent is 1,1,2,2 - tetrafluoroethyl 2,2,3,3 - tetrafluoropropyl ether;

[0234] The first lithium salt comprises lithium bis(fluorosulfonyl)imide (LiFSi);

[0235] The second lithium salt comprises lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide or lithium difluoro(oxalato)borate; and

[0236] The diluent comprises 1,3,2-dioxathiane 2,2-dioxide, 1,3,2-dioxolane 2,2-dioxide, ethoxy(pentafluoro)phosphazene or tris(trimethylsilyl) phosphate.

[0237] In some embodiments, the electrolyte composition is an electrolyte composition having the following composition:

[0238] (1) about 47.9 mol% of 1,2-dimethoxyethane,

[0239] about 8.3 mol% of 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether,

[0240] about 11.4 mol% of 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether,

[0241] about 29.7 mol% of lithium bis(fluorosulfonyl)imide (LiFSi),

[0242] about 2.0 mol% of lithium difluoro(oxalato)borate and

[0243] about 0.7 mol% of ethoxy(pentafluoro)phosphazene, or

[0244] (2) about 40.5 mol% of 1,2-dimethoxyethane,

[0245] about 17.6 mol% of 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane, about 12.6 mol% of 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether,

[0246] about 26.2 mol% of lithium bis(fluorosulfonyl)imide (LiFSi),

[0247] about 2.3 mol% of lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide, and

[0248] about 0.8 mol% of ethoxy(pentafluoro)phosphazene.

[0249] In some embodiments, the electrolyte composition is an electrolyte composition having the following composition:

[0250] about 47.9 mol% of 1,2-dimethoxyethane,

[0251] 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether in an amount of about 8.3 mol%,

[0252] 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether in an amount of about 11.4 mol%,

[0253] lithium bis(fluorosulfonyl)imide in an amount of about 29.7 mol%,

[0254] lithium difluoro(oxalato)borate in an amount of about 2.0 mol%, and

[0255] ethoxy(pentafluoro)triphosphazene in an amount of about 0.7 mol%.

[0256] In some embodiments, the electrolyte composition is an electrolyte composition having the following composition:

[0257] 1,2-dimethoxyethane in an amount of about 40.5 mol%,

[0258] 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane in an amount of about 17.6 mol%, 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether in an amount of about 12.6 mol%,

[0259] lithium bis(fluorosulfonyl)imide in an amount of about 26.2 mol%,

[0260] lithium 4,5-dicyano-2-(trifluoromethyl)imidazolium in an amount of about 2.3 mol%, and

[0261] ethoxy(pentafluoro)triphosphazene in an amount of about 0.8 mol%.

[0262] The electrolyte composition of the present invention can have any suitable conductivity. For example, the conductivity of the electrolyte composition of the present invention can be greater than 1 mS / cm, or greater than 2, 3, 4, 5, 6, 7, 8, 9 or greater than 10 mS / cm. Representative conductivities of the electrolyte composition of the present invention include, but are not limited to, about 1 mS / cm, or about 2, 3, 4, 5, 6, 7, 8, 9 or about 10 mS / cm.

[0263] In some embodiments, the electrolyte composition is an electrolyte composition in which the conductivity is greater than 2 mS / cm. In some embodiments, the electrolyte composition is an electrolyte composition in which the conductivity is greater than 3 mS / cm. In some embodiments, the electrolyte composition is an electrolyte composition in which the conductivity is greater than 5 mS / cm.

[0264] The electrolyte composition of the present invention can have any suitable kinematic viscosity. For example, the kinematic viscosity of the electrolyte composition of the present invention can be less than 10 cP, or less than 9 cP, less than 8 cP, less than 7 cP, less than 6 cP, less than 5 cP, less than 4 cP, less than 3 cP, less than 2 cP or less than 1 cP. In some embodiments, the electrolyte composition is an electrolyte composition in which the kinematic viscosity is less than 10 cP. In some embodiments, the electrolyte composition is an electrolyte composition in which the kinematic viscosity is less than 5 cP.

[0265] In some embodiments, the electrolyte composition is an electrolyte composition in which the conductivity is greater than 5 mS / cm and the kinematic viscosity is less than 5 cP.

[0266] In some embodiments, the electrolyte composition of the present invention does not contain a carbonate solvent. In some embodiments, the electrolyte composition of the present invention is substantially free of a carbonate solvent. Representative carbonate solvents include, but are not limited to, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, n-propyl propionate, vinylene carbonate, ethylene carbonate, fluoroethylene carbonate or propylene carbonate. In some embodiments, the electrolyte composition of the present invention does not contain a fluorinated carbonate solvent. In some embodiments, the electrolyte composition of the present invention is substantially free of a fluorinated carbonate solvent. Representative fluorinated carbonate solvents include, but are not limited to, fluoroethylene carbonate, CH3OC(O)OCH2CF3, CH3OC(O)OCH2CF2CHF2, CH3OC(O)OCH2CF2CHF2, CF3CH2OC(O)OCH2CF3, CH3OC(O)OCH2CF2CF2CF3, CH3CH2OC(O)OCH2CF2CF3, CH3CH2OC(O)OCH2CF2CHF2 or CH3OC(O)OCH2CF2CF2CF3. In some embodiments, the electrolyte composition of the present invention does not contain fluoroethylene carbonate. In some embodiments, the electrolyte composition of the present invention is substantially free of fluoroethylene carbonate. When a carbonate solvent is present in the electrolyte composition of the present invention, the carbonate solvent is present in an amount of less than 5 mol%, or less than 4, 3, 2, 1, 0.5, 0.4, 0.3, 0.2 or less than 0.1 mol%.

[0267] IV. Electrochemical Device

[0268] In some embodiments, the present invention provides an electrochemical device comprising an anode; a cathode; a separator between the anode and the cathode; and the electrolyte composition of the present invention.

[0269] In some embodiments, the electrochemical device is an electrochemical cell. In some embodiments, the electrochemical cell includes a positive electrode, a negative electrode, a separator, and an electrolyte. The separator is disposed between the positive electrode and the negative electrode. The separator provides electrical isolation between the positive electrode and the negative electrode. At least a portion of the electrolyte is disposed within the separator.

[0270] Any suitable polymer can be used as the separator of the electrochemical device of the present invention. For example, the separator can include an intrinsically microporous polymer. Intrinsically microporous polymers useful in the electrochemical devices of the present invention include those described in U.S. Patent Nos. 10,710,065 and 11,394,082, and U.S. Publication Nos. 2021 / 0309802 and 2019 / 0326578, each of which is incorporated herein by reference in its entirety.

[0271] There are two different types of PIMs, i) non-network (linear) polymers that may be soluble in organic solvents, and ii) network polymers that are generally insoluble, depending on the monomer selection. PIMs have internal molecular free volume (IMFV), which is a measure of concavity and is defined by Swager as the volume of concave units relative to non-concave ones [T M Long and T M Swager, “Minimization of Free Volume: Alignment of Triptycenes in Liquid Crystals and Stretched Polymers”, Adv. Mater, 13, 8, 601 - 604, 2001]. The intrinsic microporosity of linear PIMs is thought to arise from the impenetrable concavity created by their twisted structure, while in network PIMs, the micropores are also thought to originate from the concavity associated with macrocycles. [N B McKewon, P M Budd, “Exploitation of Intrinsic Microporosity in Polymer-Based materials”, Macromolecules, 43, 5163 - 5176, 2010].

[0272] The membrane layer can be in the form of a pressed powder, a fiber assembly, a compressed pellet, a film cast from a solution (e.g., onto a membrane support), a sprayed or coated film, a composite composed of multiple independent membrane layers, a self-supporting membrane, or a supported membrane (e.g., supported by a membrane support).

[0273] In some embodiments, the membrane layer has a thickness between about 5 nanometers and 20 micrometers, or between about 100 nanometers and 10 micrometers, or more specifically between about 500 nanometers and 5 micrometers.

[0274] In some embodiments, the separator comprises an intrinsically microporous polymer. In some embodiments, the separator comprises an intrinsically microporous polymer of the following formula:

[0275]

[0276] where each R is independently H or C 1-6 alkylene-NR a R b and each R a and R b are independently C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl or C 3-8 cycloalkyl, alternatively, R a and R b combine with the nitrogen atom to which they are attached to form a 4- to 8-membered heterocycloalkyl having 0 to 2 additional heteroatoms each independently being N, O or S.

[0277] In some embodiments, the separator comprises an intrinsically microporous polymer. In some embodiments, the separator comprises PIM-1:

[0278]

[0279] In some embodiments, the separator comprises an intrinsically microporous polymer. In some embodiments, the separator comprises PIM-13:

[0280]

[0281] In some embodiments, the separator comprises a first membrane layer. The first membrane layer can be an independent layer, supported by a membrane support or supported by one of the electrodes.

[0282] In some embodiments, the separator further comprises a membrane support laminated to the first membrane layer. The membrane support is permeable to the electrolyte solvent. The membrane support can be a porous polymer of polypropylene, polyethylene, polyacrylonitrile, cellulose or a combination thereof. The average pore diameter of the membrane support is at least about 10 nanometers. The first membrane layer can be disposed between the membrane support and the negative electrode.

[0283] In some embodiments, the separator further comprises a second membrane layer laminated to the membrane support. The membrane support can be disposed between the first membrane layer and the second membrane layer. The first membrane layer is permeable to a first species, thereby providing ionic communication between the positive electrode and the negative electrode, and wherein the first membrane layer is substantially impermeable to the liquid electrolyte. In some embodiments, the second membrane layer comprises a ceramic material selected from alumina, silica, silicon carbide, titanium dioxide, magnesium oxide, tin oxide, cerium oxide, zirconium oxide, barium titanate, yttrium oxide, boron nitride and ion-conductive ceramics.

[0284] In some embodiments, the first film layer interfaces directly with the negative and positive electrodes.

[0285] In some embodiments, the electrochemical device is a lithium-ion battery pack having a carbon-based, metallic, or metalloid anode and a metal oxide or conversion cathode.

[0286] V. Examples

[0287] Overview

[0288] The components used in the ternary electrolyte compositions exemplified below are listed in Table 1.

[0289] Table 1. Components of the ternary electrolyte compositions

[0290]

[0291]

[0292]

[0293]

[0294] 1 P – primary solvent; M – mediating solvent; D – diluent; A – additive; Li – lithium salt.

[0295] The HOMO and LUMO energies of the additives were determined by density functional theory (DFT) at the B3LYP-D3 / 6-31g** theoretical level using Release 2022-3: Jaguar, LLC, New York, NY, 2021 in an implicit DMSO solvent environment. The simulated structures were geometrically optimized, and the HOMO and LUMO were determined via single-point energy calculations. The oxidation potential (V, relative to Li / Li+) was determined as a function of the HOMO energy (eV) according to the following formula:

[0296] Oxidation potential (V) = HOMO (eV) * (-1.01906) - 1.29162

[0297] The HOMO and LUMO energies as determined in the DFT calculations represent the pure molecules in an implicit DMSO solvent environment. In an actual electrolyte system, coordination with the solvent and electrolyte salt via dipole interactions will (respectively) affect the HOMO and LUMO energies and thus the oxidation and reduction reactivity. The magnitude and direction of this frontier molecular orbital effect will vary with the coordination site (region of HOMO or LUMO orbital density), electrolyte concentration, and strength of the dipole interaction.

[0298] A discussion on the screening of electrolyte additives for applying theory to lithium-ion battery pack applications is provided: Jankowski P, Wieczorek W, Johansson P. SEI-forming electrolyte additives for lithium-ion batteries: development and benchmarking of computational approaches. J Mol Model. 2017. A further review on electrolyte engineering for classifying the mechanical functions of additives using DFT is provided: He, W. Research, 2022, 1-52.

[0299] Table 2. Density Functional Theory of Additive Components

[0300]

[0301] Example 1: Ternary blend where the mediating solvent is 1H,1H,5H - octafluoropentyl 1,1,2,2 - tetrafluoroethyl ether Preparation of electrolyte

[0302] Add 6.619 g of 1,2-dimethoxyethane and 8.506 g of lithium bis(fluorosulfonyl)imide to a dry flask under a dry atmosphere. Stir the solution until the lithium salt is completely dissolved. Add 0.438 g of lithium difluoro(oxalato)borate to the same flask and dissolve it completely with stirring. After the solution is homogeneous, add 4.210 g of 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether. After the solution is homogeneous again, add 4.051 g of 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether. Finally, add 0.303 g of ethoxy(pentafluoro)phosphazene and stir the clear solution for 15 minutes. The density of this electrolyte solution is 1.40 g / mL. The conductivity is 3.52 mS / cm. The dynamic viscosity is 8.77 cP.

[0303] Table 3. Ternary Blended Electrolyte with 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether (M-d) as the Mediating Solvent

[0304]

[0305] Example 2: Ternary blend where the mediating solvent is 2-(2-(2,2 - difluoroethoxy)ethoxy)-1,1,1 - trifluoroethane (M - c) Preparation of ternary blend electrolyte

[0306] Add 1.750 g of 1,2 - dimethoxyethane and 2.347 g of lithium bis(fluorosulfonyl)imide to a dry flask under a dry atmosphere. Stir the solution until the lithium salt is completely dissolved. Add 0.156 g of lithium difluoro(oxalato)borate to the same flask and dissolve it completely with stirring. After the solution is homogeneous, add 1.752 g of 2-(2-(2,2 - difluoroethoxy)ethoxy)-1,1,1 - trifluoroethane. After the solution is homogeneous again, add 1.403 g of 1,1,2,2 - tetrafluoroethyl 2,2,3,3 - tetrafluoropropyl ether. Finally, add 0.107 g of ethoxy(pentafluoro)phosphazene and stir the clear solution for 15 minutes. The density of this electrolyte solution is 1.38 g / mL. The conductivity is 4.34 mS / cm. The dynamic viscosity is 6.68 cP.

[0307] Table 4. Ternary blend electrolyte with 2-(2-(2,2 - difluoroethoxy)ethoxy)-1,1,1 - trifluoroethane as the mediating solvent

[0308]

[0309] Example 3: Preparation of ternary blend electrolyte where the main solvent is 1,2 - diethoxyethane

[0310] Add 6.605 g of 1,2 - diethoxyethane and 7.241 g of lithium bis(fluorosulfonyl)imide to a dry flask under a dry atmosphere. Stir the solution until the lithium salt is completely dissolved. Add 0.216 g of lithium difluoro(oxalato)borate to the same flask and dissolve it completely with stirring. After the solution is homogeneous, add 4.065 g of 1H,1H,5H - octafluoropentyl - 2,2 - tetrafluoroethyl ether. After the solution is homogeneous again, add 4.058 g of 1,1,2,2 - tetrafluoroethyl 2,2,3,3 - tetrafluoropropyl ether. Finally, add 0.305 g of ethoxy(pentafluoro)phosphazene and stir the clear solution for 15 minutes. The density of this electrolyte solution is 1.37 g / mL. The conductivity is 2.52 mS / cm. The dynamic viscosity is 19.80 CP.

[0311]

[0312] Example 4: Cycle life

[0313] Construct a lithium - metal battery cell containing the exemplified electrolyte as follows: First, generate a device stack containing a lithium or lithium - alloy anode (20 μm lithium on a 10 μm copper foil current collector) with an active area of 3 cm x 4 cm (12 cm 2 ), a separator (16 μm polyethylene), and a cathode (3.8 mAh / cm 2NMC-811), which is contained in a three-sided sealed laminated bag. Then the electrolyte as exemplified (2.0 g / Ah) is added to these pouch cells, and the remaining open side of the battery pack pouch cells is vacuum-sealed. Then the lithium metal battery pack cells are placed in a pressure jig at 100 PSI and allowed to equilibrate for a standing period of 12 - 48 hours. The cycle life is determined after cycling according to cycle life protocol P1 or P2 and is equal to the number of charge and discharge cycles of the battery when it reaches 80% of its initial capacity (referred to as cycle 2).

[0314] Cycle life P1: The lithium metal battery pack cells are cycled at a charge rate of 1C (current density of 3.8 mA / cm 2 ) and a discharge rate of C / 2 (discharge current density of 1.9 mA / cm 2 ). At the first cycle and every 25 cycles thereafter, a rate performance test is specified in the cycle protocol, where a slow C / 10 charge is completed. At the second cycle and every 50 cycles thereafter, a Hybrid Pulse Power Characterization (HPPC) experiment is specified in the cycle protocol. The HPPC cycles are not counted towards the total cycle life.

[0315] Cycle life P2: The lithium metal battery pack cells are cycled at a charge rate of C / 3 (current density of 1.27 mA / cm 2 ) and a discharge rate of C / 3 (discharge current density of 1.27 mA / cm 2 ).

[0316] Cycle life P3: The lithium metal battery pack cells are cycled at a charge rate of C / 5 (current density of 0.76 mA / cm 2 ) and a discharge rate of 1D (discharge current density of 3.8 mA / cm 2 ).

[0317] Example 5: Cycle life of electrolyte with PIM - 13 coated separator

[0318] A lithium metal battery pack cell containing the exemplified electrolyte is constructed as follows: First, a device stack is produced, which contains a lithium or lithium alloy anode (20 μm lithium on a 10 μm copper foil current collector) with an active area of 3 cm x 4 cm (12 cm 2 ), a PIM-13 coated separator, and a cathode (3.8 mAh / cm 2 NMC-811), which is contained in a three-sided sealed laminated bag. The PIM-13 coated separator comprises a 16 μm PE separator substrate that is coated with PIM-13 on one side (1.03 g / m 2Gravimetric mass load), interfacing with the lithium metal anode. Then the electrolyte as exemplified (2.0 g / Ah) was added to these pouch cells and the remaining open side of the battery pack pouch cells was vacuum sealed. Then the lithium metal battery pack cells were placed in a pressure jig at 100 PSI and allowed to equilibrate for a 48-hour rest period. The cycle life was determined after cycling according to cycle life protocol P2 and was equal to the number of charge and discharge cycles of the battery when it reached 80% of its initial capacity (referred to as cycle 2).

[0319] Table 5. Cycle Life

[0320] Example Cycle life - P1 Cycle life - P2 Cycle life (PIM - 13 separator) P2 Cycle life - P3 1-1 86 90 206 1-2 103 135 1-3 101 128 225 1-4a 114 142 150 1-4b 126 161 156 240 1-5 103 1-6 107 1-7 103 138 1-8 106 1-9 103 1-10 103 1-11 133 152 1-12 137 158 1-13 131 141 142 1-14 129 1-15 132 1-16 128 154 2-1 100 139 147 260 2-2 74 105 225 3-1 142 3-2 136 3-3 134 193 166 248 3-4 130 3-5 130 3-6 129 E4 53 86 89 89 E5 69 116 E6 58

[0321] Example 6: Simulating Li+ coordination energy

[0322] Density functional theory was used to simulate the lithium coordination energy of the exemplified primary solvent, mediating solvent, and diluent compounds. Molecules were constructed and minimized using the OPLS_2005 force field and then geometrically optimized using DFT at the B3LYP-d3 / 6-31g** theoretical level in an implicit DMSO solvent environment. According to the following formula, the final energy of the optimized E[Li+]--[solvent compound] complex was subtracted from the sum of the final energies of the uncoordinated Li+ ion and the corresponding solvent compound. The more negative the Li+ coordination energy, the stronger the Li+ coordination complex formed between the solvent compound and the lithium ion.

[0323] Li+ coordination energy = E[Li+]--[solvent compound] – (E[Li+] + E[solvent compound])

[0324] Table 6. DFT Coordination Energies of Selected Primary Solvents, Mediating Solvents, and Diluents

[0325] Component Name Li+ coordination energy P - a 1,2 - dimethoxyethane -43.65 P - b 1,2 - diethoxyethane -45.00 M - a 2,2,3,3 - tetrafluoro - 1,4 - dimethoxybutane -36.93 M - c 2-(2-(2,2 - difluoroethoxy)ethoxy)-1,1,1 - trifluoroethane -54.27 M - d / D - a 1H,1H,5H - octafluoropentyl 1,1,2,2 - tetrafluoroethyl ether -31.25 D - b 1,1,2,2 - tetrafluoroethyl 2,2,3,3 - tetrafluoropropyl ether -33.62

[0326] Example 7: Simulating solvation cluster analysis in bulk electrolyte

[0327] Molecular dynamics was used ( Release 2022-3:Desmond Molecular DynamicsSystem,D.E.Shaw Research,New York,NY,2021.Maestro-Desmond InteroperabilityTools, (New York, NY, 2021) was used to simulate the lithium solvation environment of electrolyte 2-1). An amorphous system containing a total of 100 molecules was generated according to the molar ratio specified in Example 2-1, and then NPT (1 atm, 300 K) molecular dynamics simulations were performed for a duration of 500 ns. The average coordination environment (% basis) as a function of the distance from each Li+ ion was determined using radial distribution function analysis. The resulting average Li+ coordination environment as a function of the distance from the central Li+ ion is summarized in Table 7.

[0328] Table 7. Coordination environment as a function of the distance from Li+ in the molecular dynamics simulation of electrolyte 2-1.

[0329]

[0330] Example 8: Electrolyte (E4)

[0331] An electrolyte mixture was prepared by mixing the following components (mol%): 48% dimethyl carbonate, 39% fluoroethylene carbonate, 1% toluene diisocyanate, 10% lithium bis(fluorosulfonyl)imide, and 2% lithium difluoro(oxalato)borate.

[0332] Example 9: Electrolyte (E5)

[0333] 1.95 g of 1,2-dimethoxymethane and 3.929 g of lithium bis(fluorosulfonyl)imide were added to a dry flask under a dry atmosphere. The solution was stirred until the lithium salt was completely dissolved. After the solution was homogeneous, 13.050 g of 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether was added. The clear solution was stirred for 15 minutes. The density of electrolyte solution E5 was 1.50 g / mL. The conductivity was 1.52 mS / cm. The dynamic viscosity was 3.11 cP.

[0334] Example 10: Electrolyte (E6)

[0335] 3.31 g of 1,2-dimethoxymethane and 3.452 g of lithium bis(fluorosulfonyl)imide were added to a dry flask under a dry atmosphere. The solution was stirred until the lithium salt was completely dissolved. After the solution was homogeneous, 11.70 g of 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether was added. The clear solution was stirred for 15 minutes. The density of electrolyte solution LIT009 was 1.42 g / mL. The conductivity was 5.25 mS / cm. The dynamic viscosity was 2.56 cP.

[0336] Example 11: Analysis of electrolyte composition by nuclear magnetic resonance spectroscopy (NMR) after battery cycling

[0337] Compositional analysis studies were performed on Example Electrolytes 1-4 before and after battery cycling to examine the consumption of additive compounds that form the SEI and CEI. The first pristine samples of Electrolytes 1-4 were obtained immediately after mixing the samples. The second post-mortem samples of Example Electrolytes 1-4 were collected from batteries that had been cycled to 80% capacity. The two samples were analyzed by 1 H, 13 C, 19 F, 31 P, and 11 B NMR spectroscopy. In the pristine samples of Electrolytes 1-4, all constituent components were observed (Table 8). In the post-mortem samples of Electrolytes 1-4, components A-g (observed in the pristine sample via 31 P NMR) and Li-b (observed in the pristine sample via 19 F and 11 B NMR) could no longer be detected by NMR, indicating that their concentrations in solution were below the detection limit (Table 9). In the post-mortem samples, components LiFSI (observed via 19 F NMR), P-a (observed via 1 H and 13 C NMR), M-d / D-a and D-b (both observed via 19 F NMR) were still observed, indicating that they remained in solution throughout the standard operating life of the battery.

[0338] Table 8. Pristine NMR of Electrolytes 1-4

[0339]

[0340] Table 9. Post-mortem NMR of Electrolytes 1-4

[0341]

[0342]

[0343] Although the foregoing invention has been described in relatively great detail by way of illustration and example for purposes of clarity of understanding, those skilled in the art will appreciate that certain changes and modifications may be practiced within the scope of the appended claims. Additionally, each reference provided herein is hereby incorporated by reference in its entirety to the extent as if each reference were individually incorporated by reference. In the event of a conflict between this application and the references provided herein, this application shall control.

Claims

1. An electrolyte composition, the electrolyte composition comprising: A primary solvent; A mediating solvent; A diluent; and A first lithium salt, wherein the primary solvent, the mediating solvent, and the diluent are each different.

2. The electrolyte composition according to claim 1, wherein the electrolyte composition does not contain a carbonate solvent.

3. The electrolyte composition according to claim 1 or 2, wherein the primary solvent comprises an ether, a glycol dimethyl ether, a cyclic ether, or a combination thereof.

4. The electrolyte composition according to any one of claims 1 to 3, wherein the primary solvent comprises diethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,3-dioxolane, 1,4-dioxane, 1,3-dioxane, or a combination thereof.

5. The electrolyte composition according to any one of claims 1 to 4, wherein the primary solvent comprises diethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, or a combination thereof.

6. The electrolyte composition according to any one of claims 1 to 5, wherein the primary solvent comprises 1,2-diethoxyethane.

7. The electrolyte composition according to any one of claims 1 to 5, wherein the primary solvent comprises 1,2-dimethoxyethane.

8. The electrolyte composition according to any one of claims 1 to 7, wherein the primary solvent is present in the electrolyte composition in an amount of 20 to 70 mol%.

9. The electrolyte composition according to any one of claims 1 to 8, wherein the primary solvent is present in the electrolyte composition in an amount of 35 to 50 mol%.

10. The electrolyte composition according to any one of claims 1 to 9, wherein the mediating solvent comprises a fluorinated ether, a fluorinated glycol dimethyl ether, a fluorinated cyclic ether, or a combination thereof.

11. The electrolyte composition according to any one of claims 1 to 10, wherein the mediating solvent comprises 2,2,3,3-tetrafluoro-1,4-dimethoxybutane, 2-(2-ethoxyethoxy)-1,1,1-trifluoroethane, 1,2-bis(2,2-difluoroethoxy)ethane, 1,2-bis(2,2,2-trifluoroethoxy)ethane, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane, or a combination thereof.

12. The electrolyte composition according to any one of claims 1 to 11, wherein the mediating solvent comprises 2,2,3,3-tetrafluoro-1,4-dimethoxybutane, 1,2-bis(2,2-difluoroethoxy)ethane, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane, or a combination thereof.

13. The electrolyte composition according to any one of claims 1 to 12, wherein the mediating solvent comprises 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane, or a combination thereof.

14. The electrolyte composition according to any one of claims 1 to 13, wherein the mediating solvent comprises 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether.

15. The electrolyte composition according to any one of claims 1 to 14, wherein the mediating solvent comprises 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane.

16. The electrolyte composition according to any one of claims 1 to 15, wherein the mediating solvent is present in the electrolyte composition in an amount of 1 to 30 mol%.

17. The electrolyte composition according to any one of claims 1 to 16, wherein the mediating solvent is present in the electrolyte composition in an amount of 5 to 20 mol%.

18. The electrolyte composition according to any one of claims 1 to 17, wherein the diluent comprises a fluorinated ether, a fluorinated glycol dimethyl ether, a cyclic ether, a fluorinated cyclic ether, or a combination thereof.

19. The electrolyte composition according to any one of claims 1 to 18, wherein the diluent comprises 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, or a combination thereof.

20. The electrolyte composition according to any one of claims 1 to 19, wherein the diluent comprises 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, or a combination thereof.

21. The electrolyte composition according to any one of claims 1 to 20, wherein the diluent comprises 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether.

22. The electrolyte composition according to any one of claims 1 to 21, wherein the diluent is present in the electrolyte composition in an amount of 1 to 30 mol%.

23. The electrolyte composition according to any one of claims 1 to 22, wherein the diluent is present in the electrolyte composition in an amount of 5 to 20 mol%.

24. The electrolyte composition according to any one of claims 1 to 23, wherein the first lithium salt comprises lithium bis(fluorosulfonyl)imide (LiFSi), or lithium hexafluorophosphate, or a combination thereof.

25. The electrolyte composition according to any one of claims 1 to 24, wherein the first lithium salt comprises lithium bis(fluorosulfonyl)imide (LiFSi).

26. The electrolyte composition according to any one of claims 1 to 25, wherein the first lithium salt is present in the electrolyte composition in an amount of 10 to 50 mol%.

27. The electrolyte composition according to any one of claims 1 to 26, wherein the first lithium salt is present in the electrolyte composition in an amount of 25 to 35 mol%.

28. The electrolyte composition according to any one of claims 1 to 27, wherein the molar ratio of the main solvent to the first lithium salt is from 3.5:1 to 1.4:

1.

29. The electrolyte composition according to any one of claims 1 to 28, wherein the molar ratio of the main solvent to the first lithium salt is from 2.0:1 to 1.4:

1.

30. The electrolyte according to any one of claims 1 to 29, further comprising a second lithium salt different from the first lithium salt.

31. The electrolyte composition according to claim 30, wherein the second lithium salt comprises lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide, lithium difluoro(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorophosphate, lithium nitrate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, or a combination thereof.

32. The electrolyte composition according to claim 30 or 31, wherein the second lithium salt comprises lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide, lithium difluoro(oxalato)borate, or a combination thereof.

33. The electrolyte composition according to any one of claims 30 to 32, wherein the second lithium salt comprises lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide.

34. The electrolyte composition according to any one of claims 30 to 32, wherein the second lithium salt comprises lithium difluoro(oxalato)borate.

35. The electrolyte composition according to any one of claims 30 to 32, wherein the second lithium salt comprises lithium nitrate.

36. The electrolyte composition according to any one of claims 30 to 35, wherein the second lithium salt is present in the electrolyte composition in an amount of 0.1 to 5 mol%.

37. The electrolyte composition according to any one of claims 30 to 36, wherein the second lithium salt is present in the electrolyte composition in an amount of 1 to 3 mol%.

38. The electrolyte composition according to any one of claims 1 to 37, further comprising an additive.

39. The electrolyte composition according to any one of claims 1 to 38, wherein the additive comprises 1,3,2-dioxathiane 2,2-dioxide, 1,3,2-dioxolane 2,2-dioxide, 2-fluoropyridine, bis(trimethylsilyl) malonate, dimethylacetamide, phenyltrifluorosilane, ethoxy(pentafluoro)triphosphazene, fluoroethylene carbonate, p-tolylsulfur pentafluoride, succinonitrile, tetrafluoroterephthalonitrile, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, tris(trimethylsilyl) phosphate, or a combination thereof.

40. The electrolyte composition according to any one of claims 1 to 39, wherein the additive comprises 1,3,2-dioxathiane 2,2-dioxide.

41. The electrolyte composition according to any one of claims 1 to 39, wherein the additive comprises 1,3,2-dioxolane 2,2-dioxide.

42. The electrolyte composition according to any one of claims 1 to 39, wherein the additive comprises ethoxy(pentafluoro)triphosphazene.

43. The electrolyte composition according to any one of claims 1 to 39, wherein the additive comprises tris(trimethylsilyl) phosphate or a combination thereof.

44. The electrolyte composition according to any one of claims 1 to 43, wherein the additive is present in the electrolyte composition in an amount of 0.1 to 5 mol%.

45. The electrolyte composition according to any one of claims 1 to 44, wherein the additive is present in the electrolyte composition in an amount of 0.8 to 2.5 mol%.

46. The electrolyte composition according to any one of claims 1 to 45, wherein: the main solvent comprises 1,2-dimethoxyethane; the mediating solvent is 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether or 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane; the diluent is 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether; the first lithium salt comprises lithium bis(fluorosulfonyl)imide (LiFSi); the second lithium salt comprises lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide or lithium difluoro(oxalato)borate; and the additive comprises 1,3,2-dioxathiolane 2,2-dioxide, 1,3,2-dioxolane 2,2-dioxide, ethoxy(pentafluoro)phosphazene or tris(trimethylsilyl) phosphate.

47. The electrolyte composition according to any one of claims 1 to 46, the electrolyte composition having the following composition: (1) about 47.9 mol% of 1,2-dimethoxyethane, about 8.3 mol% of 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, about 11.4 mol% of 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, about 29.7 mol% of lithium bis(fluorosulfonyl)imide (LiFSi), about 2.0 mol% of lithium difluoro(oxalato)borate and about 0.7 mol% of ethoxy(pentafluoro)phosphazene, or (2) about 40.5 mol% of 1,2-dimethoxyethane, about 17.6 mol% of 2-(2-(2,2-difluoroethoxy)ethoxy)-1,1,1-trifluoroethane, about 12.6 mol% of 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, about 26.2 mol% of lithium bis(fluorosulfonyl)imide (LiFSi), about 2.3 mol% of lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide and about 0.8 mol% of ethoxy(pentafluoro)phosphazene.

48. The electrolyte composition according to any one of claims 1 to 47, wherein the conductivity is greater than 2 mS / cm.

49. The electrolyte composition according to any one of claims 1 to 48, wherein the kinematic viscosity is less than 10 cP.

50. An electrochemical device, the electrochemical device comprising: an anode; a cathode; a separator between the anode and the cathode; and The electrolyte composition according to any one of claims 1 to 49.

51. The electrochemical device according to claim 50, wherein the separator comprises an intrinsically microporous polymer.

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