Carbonate compounds for energy storage device electrolyte compositions and methods thereof

Abstract

The present invention provides electrolyte solvents, co-solvents and formulations for energy storage devices with improved performance. The improved performance may be achieved as improved cycling stability, as well as coulombic efficiency, capacity, or conductivity at very high temperatures (e.g., at least about 70 DEG C or about 70-85 DEG C). Such electrolyte formulations may comprise compounds of formula (I), such as dimethyl 2, 5-dioxaadipate (DMOHC) and diethyl 2, 5-dioxaadipate (DEOHC): # imgabs0 #

Description

[0001] Incorporation by reference of any priority application

[0002] Any and all applications claiming foreign or domestic priority as indicated in the Application Data Sheet or PCT request at the time of filing this application are hereby incorporated by reference pursuant to 37 CFR 1.57 and Sections 4.18 and 20.6. This application claims priority to U.S. Provisional Patent Application No. 63 / 351,267, filed on June 10, 2022, entitled “Carbonate Compounds for Electrolyte Compositions of Energy Storage Devices and Methods Thereof,” the disclosure of which is incorporated herein by reference in its entirety and for all purposes. Background Art Technical Field

[0003] The present disclosure relates generally to energy storage devices, and in particular to improved electrolyte formulations for energy storage devices.

[0004] Related technical notes

[0005] Energy storage devices are widely used to provide power to electronic, electromechanical, electrochemical and other useful devices. Such batteries include primary chemical batteries, secondary (rechargeable) batteries, fuel cells and various capacitors, including supercapacitors. Increasing the operating voltage and temperature of energy storage devices (including batteries and capacitors) would be desirable to enhance energy storage, increase power capacity and expand practical use cases.

[0006] Lithium-ion batteries have been relied upon as a source of power for many commercial and industrial applications, such as consumer devices, productivity equipment, and vehicles powered by the batteries. However, the demand for energy storage devices is continuing to grow rapidly. For example, the vehicle industry is developing vehicles that rely on compact and efficient energy storage, such as plug-in hybrid vehicles and pure electric vehicles. Lithium-ion batteries are well suited to meet future needs, but energy density needs to be increased to provide longer-life batteries that can travel farther on a single charge. The electrolyte is a component in conventional lithium-ion batteries that determines the electrochemical performance and safety of those batteries, with the compatibility between the electrodes and the electrolyte determining in part the cell performance of the battery. Summary of the invention

[0007] To summarize the present invention and the advantages achieved over the prior art, certain objects and advantages of the present invention are described herein. Such objects or advantages may not all be achieved in any particular embodiment of the present invention. Thus, for example, those skilled in the art will recognize that the present invention may be embodied or performed in a manner that achieves or optimizes one advantage or a group of advantages taught herein without necessarily achieving other objects or advantages taught or inspired herein.

[0008] In one aspect, an energy storage device is described. The energy storage device comprises: a cathode; an anode; a separator disposed between the cathode and the anode; and an electrolyte comprising a solvent and an alkali metal salt, wherein the solvent comprises a compound represented by formula (I): Wherein: R1 and R2 are each independently an optionally substituted C 1-12 alkyl; and R3 is an optionally substituted C 1-12 Alkylene.

[0009] In some embodiments, R1 and R2 are each independently selected from methyl and ethyl; and R3 is (-CH2CH2-). In some embodiments, R1 and R2 are each independently selected from optionally substituted methyl, optionally substituted ethyl, optionally substituted propyl, optionally substituted butyl, optionally substituted isopropyl, optionally substituted isobutyl and optionally substituted sec-butyl. In some embodiments, the optional substitutions of R1 and R2 are each independently selected from at least one halogen. In some embodiments, the optional substitutions of R3 are selected from at least one C 1-12 Alkyl, C 1-12 Haloalkyl, halogen, and combinations thereof. In some embodiments, R3 is optionally substituted ethylene or optionally substituted propylene.

[0010] In some embodiments, the compound is represented by formula (Ia): Wherein R4, R5, R6 and R7 are each independently selected from -H, halogen, C 1-12 Alkyl and C 1-12 Haloalkyl. In some embodiments, R4, R5, R6 and R7 are each independently selected from -CH2CF2CF3. In some embodiments, R4 is selected from -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C- and -CF3. In some embodiments, R5 is selected from -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C- and -CF3. In some embodiments, R6 is selected from -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C- and -CF3. In some embodiments, R7 is selected from -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C- and -CF3.

[0011] In some embodiments, the compound is represented by formula (Ib): Among them, R8, R9, R 10 , R 11 , R 12 and R 13are each independently selected from -H, halogen, C 1-12 Alkyl and C 1-12 Halogenated alkyl.

[0012] In some embodiments, the compound of formula (I) is selected from

[0013] In some embodiments, the compound of formula (I) is selected from

[0014]

[0015] In some embodiments, the alkali metal salt is a sodium salt. In some embodiments, the alkali metal salt is a lithium salt. In some embodiments, the lithium salt is LiFSI. In some embodiments, the electrolyte further comprises a second solvent, the second solvent being selected from ethylene carbonate (EC), propylene carbonate (PC), vinyl ethylene carbonate (VEC), vinylene carbonate (VC), fluoroethylene carbonate (FEC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl acetate (MA), ethyl acetate (EA), propionitrile (PN), acetonitrile (AN), gluorolactone (GBL) and combinations thereof. In some embodiments, the solvent further comprises dimethyl carbonate (DMC). In some embodiments, the ratio between the solvent and the second solvent is about 1:4 to about 4:1.

[0016] In some embodiments, the energy storage device of the present disclosure has at least 96% retention of initial capacity after 2,000 hours of cycling when operating between 3.0 V and 4.3 V. In other embodiments, the energy storage device of the present disclosure provides greater than 99% retention of initial capacity after 2,000 hours of cycling when operating between 3.0 V and 3.8 V at a temperature of at least 70°C.

[0017] In another aspect, a method for preparing an energy storage device is described. The method comprises: providing a cathode, an anode, a separator provided between the cathode and the anode, and an electrolyte in a housing; wherein the electrolyte comprises a solvent and an alkali metal salt, wherein the solvent comprises a compound represented by formula (I): Wherein: R1 and R2 are each independently an optionally substituted C 1-12 alkyl; and R3 is an optionally substituted C 1-12 Alkylene. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1A It is the phase diagram of the mixture of dimethyl carbonate (DMC) and dimethyl 2,5-dioxaadipate (DMOHC) at different temperatures.

[0019] Figure 1B It is the phase diagram of the mixture of dimethyl carbonate (DMC) and ethylene carbonate (EC) at different temperatures.

[0020] Figure 2A is a plot of viscosity versus temperature data for electrolyte solutions and solvent combinations according to some embodiments relative to a baseline electrolyte system.

[0021] Figure 2B is a plot of viscosity versus temperature data for electrolyte solutions and solvent combinations according to some embodiments relative to a baseline solvent combination.

[0022] Figure 3 is a graph of data showing normalized discharge capacity versus cycle time for NMC532 / artificial graphite cells having an electrolyte system according to some embodiments relative to a baseline electrolyte system.

[0023] Figure 4 Included are data graphs showing normalized discharge capacity versus cycle time and voltage polarization versus cycle time for cells having different lithium salts and electrolyte systems according to some embodiments relative to a baseline electrolyte system.

[0024] Figure 5 Included are data graphs showing normalized discharge capacity versus cycle time and voltage polarization versus cycle time for cells having electrolyte systems containing different amounts of DMOHC relative to a baseline electrolyte system.

[0025] Fig. 6A is a bar graph showing the charge transfer resistance of a lithium iron phosphate battery having an electrolyte system according to some embodiments relative to a baseline electrolyte system.

[0026] Figure 6B is a bar graph showing voltage polarization of a lithium iron phosphate battery having an electrolyte system according to some embodiments relative to a baseline electrolyte system.

[0027] Figure 6C is a bar graph showing gas formation for a lithium iron phosphate battery having an electrolyte system according to some embodiments relative to a baseline electrolyte system.

[0028] Figure 7 is a graph of data showing average parasitic heat flow versus cycle number for lithium iron phosphate batteries having an electrolyte system according to some embodiments relative to a baseline electrolyte system.

[0029] Figure 8 is a graph of data showing normalized discharge capacity versus cycle time for lithium iron phosphate batteries having an electrolyte system according to some embodiments relative to a baseline electrolyte system.

[0030] Fig. 9 is a graph of data showing normalized discharge capacity versus cycle time for LFP / pure graphite cells having an electrolyte system according to some embodiments relative to a baseline electrolyte system.

[0031] Fig.10 is a graph of data showing normalized discharge capacity versus cycle time for NMC532 / artificial graphite (ie, “AML”) with an electrolyte system according to some embodiments relative to a baseline electrolyte system.

[0032] Fig.11 is a graph of data showing normalized discharge capacity versus cycle time for LFP / pure graphite cells having an electrolyte system according to some embodiments relative to a baseline electrolyte system.

[0033] Fig.12 is a graph of data showing normalized discharge capacity versus cycle time for LFP / pure graphite cells having an electrolyte system according to some embodiments relative to a baseline electrolyte system.

[0034] Fig.13A is a graph showing normalized discharge capacity versus cycle time for NMC532 / artificial graphite (ie, "AML") cells having an electrolyte system according to some embodiments at 70°C relative to a baseline electrolyte system.

[0035] Fig. 13B is a graph showing data for voltage polarization versus cycle time for NMC532 / artificial graphite (ie, "AML") cells having an electrolyte system according to some embodiments at 70°C relative to a baseline electrolyte system.

[0036] Fig.14 is a graph showing charge and discharge capacity versus cycle time at 70° C. for NMC532 / artificial graphite cells having an electrolyte system according to some embodiments.

[0037] Fig.15 is a graph showing normalized discharge capacity versus cycle time at 70° C. for NMC532 / artificial graphite (ie, “AML”) cells having an electrolyte system according to some embodiments.

[0038] Fig.16Included are data graphs showing normalized discharge capacity versus cycle time and voltage polarization versus cycle time for lithium iron phosphate batteries having an electrolyte system according to some embodiments relative to a baseline electrolyte system at 85°C.

[0039] Fig.17 Included are data graphs showing normalized discharge capacity versus cycle time and voltage polarization versus cycle time for NMC532 / artificial graphite (ie, "AML") cells having an electrolyte system according to some embodiments relative to a baseline electrolyte system at 85°C.

[0040] Fig.18 Included are data graphs showing normalized discharge capacity versus cycle time and voltage polarization versus cycle time for Ni83 / PG cells having an electrolyte system according to some embodiments at 85°C relative to a baseline electrolyte system.

[0041] Fig.19 Included are data graphs showing discharge capacity versus cycle time at 85° C. and normalized discharge capacity versus cycle time for Ni83 / PG batteries having an electrolyte system according to some embodiments.

[0042] Fig. 20A Included are data graphs showing discharge capacity versus cycle time at 20° C. and normalized discharge capacity versus cycle time for Ni83 / PG batteries having an electrolyte system according to some embodiments.

[0043] Fig. 20B Included are data graphs showing discharge capacity versus cycle time at 85° C. and normalized discharge capacity versus cycle time for Ni83 / PG batteries having an electrolyte system according to some embodiments.

[0044] Fig.21A Included are data graphs showing discharge capacity versus cycle time at 20° C. and normalized discharge capacity versus cycle time for NMC640 / PG cells having an electrolyte system according to some embodiments.

[0045] Fig.21B Included are data graphs showing discharge capacity versus cycle time at 85° C. and normalized discharge capacity versus cycle time for NMC640 / PG cells having an electrolyte system according to some embodiments.

[0046] Fig.22A Included are data graphs showing discharge capacity versus cycle time and normalized discharge capacity versus cycle time for Ni83 / PG cells having an electrolyte system according to some embodiments at 85°C relative to a baseline electrolyte system.

[0047] Fig. 22BIncluded are data graphs showing discharge capacity versus cycle time and normalized discharge capacity versus cycle time for Ni83 / PG cells having an electrolyte system according to some embodiments at 85°C relative to a baseline electrolyte system. DETAILED DESCRIPTION

[0048] Electrolyte formulations comprising solvents are described that can improve the life and / or energy density of energy storage devices (e.g., lithium-ion batteries and / or sodium-ion batteries) at elevated voltages and / or temperatures. Such solvents can interact with alkali metal salts (e.g., sodium salts and / or lithium salts) to improve device performance. Such solvents can interact with lithium salts to improve device performance, such as improving cycle stability at high temperatures (e.g., at least about 70-85°C). In some embodiments, the energy storage device electrolyte may include a solvent comprising a compound having formula (I) (e.g., formula (Ia) and / or formula (Ib)), as discussed below. In some embodiments, the energy storage device electrolyte may further include a LiFSI lithium salt. In addition, the energy storage device electrolyte may also include dimethyl carbonate (DMC) as a co-solvent.

[0049] In some embodiments, the energy storage device disclosed herein has at least 99% of the initial capacity retention after 3,000 hours of charge-discharge cycles when operating between 3.0V and 4.3V, or at least 96% retention when operating between 3.0V and 4.3V at a temperature of at least 70°C. Although the capacity of conventional energy storage devices and battery packs is rapidly depleted at such voltages and high temperatures, it has been found that the energy storage devices disclosed herein successfully improve the retention of their initial capacity relative to comparative energy storage devices without such electrolyte formulations. Therefore, the electrolyte formulations provided herein show improved cycling stability at high temperatures, as well as improved capacity retention during the life of the device (with nominal capacity fade).

[0050] definition

[0051] Whenever a group is described as being "optionally substituted", the group may be unsubstituted or substituted with one or more specified substituents. Similarly, when a group is described as being "unsubstituted or substituted", if substituted, the substituents may be selected from one or more specified substituents. If no substituents are specified, it means that the specified "optionally substituted" or "substituted" groups may be individually and independently selected from deuterium (D), halogen, hydroxyl, C 1-4 Alkoxy, C 1-8 Alkyl, C 3-20 Cycloalkyl, aryl, heteroaryl, heterocyclic, C 1-6 Haloalkyl, cyano, C 2-8 Alkenyl, C 2-8 Alkynyl, C 3-20The alkyl radicals may be substituted with one or more of cycloalkenyl, aryl(alkyl), heteroaryl(alkyl), heterocyclyl(alkyl), acyl, thiocarbonyl, O-carbamoyl, N-carbamoyl, O-thiocarbamoyl, N-thiocarbamoyl, C-amide, N-amide, C-thioamide, N-thioamide, S-sulfonamide, N-sulfonamide, C-carboxyl, O-carboxyl, sulfenyl, sulfinyl, sulfonyl, haloalkoxy, amino, monosubstituted amine and disubstituted amine.

[0052] As used herein, “C a To C b ”, where “a” and “b” are integers referring to the number of carbon atoms in the group. A specified group may include from “a” to “b” (inclusive) carbon atoms. Thus, for example, a “C1 to C4 alkyl” group refers to an alkyl group having 1 to 4 carbons, i.e., CH3-, CH3CH2-, CH3CH2CH2-, (CH3)2CH-, CH3CH2CH2CH2-, CH3CH2CH(CH3)-, and (CH3)3C-. If “a” and “b” are not specified, the broadest range described in these definitions should be assumed.

[0053] As used herein, the term "alkyl" refers to a fully saturated aliphatic hydrocarbon group. The alkyl moiety may be branched or straight-chain. Examples of branched alkyl groups include, but are not limited to, isopropyl, sec-butyl, tert-butyl, etc. Examples of straight-chain alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, etc. Alkyl groups may have 1 to 30 carbon atoms (when it appears herein in any case, a numerical range, such as "1 to 30", refers to each integer within a given range; for example, "1 to 30 carbon atoms" means that the alkyl group may be composed of 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc., up to and including 30 carbon atoms, although this definition also encompasses the case of the term "alkyl" where no numerical range is specified). Alkyl groups may also be intermediate alkyl groups having 1 to 12 carbon atoms. Alkyl groups may also be lower alkyl groups having 1 to 6 carbon atoms. Alkyl groups may be substituted or unsubstituted.

[0054] As used herein, the term "alkenyl" refers to a monovalent straight or branched chain group of two to thirty carbon atoms containing a carbon double bond, including but not limited to 1-propenyl, 2-propenyl, 2-methyl-1-propenyl, 1-butenyl, 2-butenyl, etc. The alkenyl group may be unsubstituted or substituted.

[0055] As used herein, the term "alkynyl" refers to a monovalent straight or branched chain group of two to thirty carbon atoms containing a carbon triple bond, including but not limited to 1-propynyl, 1-butynyl, 2-butynyl, etc. Alkynyl groups can be unsubstituted or substituted.

[0056] As used herein, the term "carbonyl" refers to C=O (ie, a carbon connected to an oxygen via a double bond).

[0057] An "alkylene" group refers to a straight-chain -CH2-tethered group that forms a bond through its terminal carbon atoms to connect molecular fragments. Examples include, but are not limited to, methylene (-CH2-), ethylene (-CH2CH2-), propylene (-CH2CH2CH2-), and butylene (-CH2CH2CH2CH2-). Lower alkylene can be substituted by replacing one or more hydrogens in the lower alkylene with a substituent listed under the "Substitution" definition.

[0058] As used herein, the term "halogen atom" or "halogen" refers to any radioactive stable atom of column 7 of the periodic table, such as fluorine, chlorine, bromine and iodine.

[0059] As used herein, "haloalkyl" refers to an alkyl group in which one or more hydrogen atoms are replaced by halogen (e.g., monohaloalkyl, dihaloalkyl, and trihaloalkyl). Such groups include, but are not limited to, chloromethyl, fluoromethyl, difluoromethyl, trifluoromethyl, 1-chloro-2-fluoromethyl, 2-fluoroisobutyl, -CH2CF3, -CH2CHF2, -CH2CH2F, -CH2CH2Cl, and -CH2CF2CF3. Haloalkyl groups may be substituted or unsubstituted.

[0060] As used herein, "haloalkoxy" refers to an alkoxy group in which one or more hydrogen atoms are replaced by halogen (e.g., monohaloalkoxy, dihaloalkoxy, and trihaloalkoxy). Such groups include, but are not limited to, chloromethoxy, fluoromethoxy, difluoromethoxy, trifluoromethoxy, and 1-chloro-2-fluoromethoxy, 2-fluoroisobutoxy. The haloalkoxy group may be substituted or unsubstituted.

[0061] As used herein, the term "alkali metal" refers to any atom in column 1 of the periodic table except hydrogen, such as lithium, sodium, potassium, rubidium, cesium, and francium.

[0062] As used herein, "salt" refers to any material that is formed when a leaving group or hydrogen in an acid form is replaced by a metal or its equivalent and that becomes ionized when dissolved in a solvent at an appropriate pKa, such as water or a polar organic solvent.

[0063] Solvents

[0064] In some embodiments, the electrolyte comprises a liquid solvent. The solvent provided herein does not need to dissolve each component, and does not need to completely dissolve each component of the electrolyte. In a further embodiment, the solvent may comprise an organic solvent. In some embodiments, the solvent may comprise one or more functional groups selected from carbonate, dimer carbonate, ether and / or ester. In some embodiments, the electrolyte comprises a solvent. In other embodiments, the electrolyte comprises a variety of solvents. In some embodiments, the solvent may comprise a decarbonated alkyl ester compound and / or a dimer compound (e.g., a didecarbonated alkyl ester compound).

[0065] In some embodiments, the solvent may comprise a compound of formula (I):

[0066]

[0067] In some embodiments, R1 and R2 are each independently an optionally substituted C 1-12 In some embodiments, R1 is an optionally substituted C 1-12 In some embodiments, R2 is an optionally substituted C 1-12Alkyl. For example, in some embodiments, R1 and R2 are each independently selected from optionally substituted methyl, optionally substituted ethyl, optionally substituted propyl, optionally substituted butyl, optionally substituted isopropyl, optionally substituted isobutyl and optionally substituted sec-butyl. In other examples, in some embodiments, R1 and R2 are each independently selected from methyl and ethyl. In some embodiments, R1 and R2 are each independently selected from methyl, ethyl, propyl, isopropyl, isobutyl and sec-butyl. In some embodiments, R1 and R2 are each optionally substituted methyl. In some embodiments, R1 and R2 are each methyl. In other embodiments, R1 and R2 are each optionally substituted ethyl. In other embodiments, R1 and R2 are each ethyl. In some embodiments, R1 and R2 are each optionally substituted propyl. In some embodiments, R1 and R2 are each propyl. In some embodiments, R1 and R2 are each optionally substituted butyl. In some embodiments, R1 and R2 are each butyl. In some embodiments, R1 and R2 are each optionally substituted isopropyl. In some embodiments, R1 and R2 are each isopropyl. In some embodiments, R1 and R2 are each optionally substituted isobutyl. In some embodiments, R1 and R2 are each isobutyl. In some embodiments, R1 and R2 are each optionally substituted sec-butyl. In some embodiments, R1 and R2 are each sec-butyl. In some embodiments, R1 is optionally substituted methyl and R2 is optionally substituted ethyl. In some embodiments, R1 is methyl and R2 is each ethyl. In certain embodiments, the optional substitutions of R1 and R2 are each independently selected from at least one halogen. In some embodiments, R1 and R2 are each methyl. In other embodiments, R1 and R2 are each ethyl. In some embodiments, R1 is methyl and R2 is ethyl.

[0068] In some embodiments, R3 is optionally substituted C 1-12 In some embodiments, R3 is an optionally substituted ethylene or an optionally substituted propylene. In some embodiments, R3 is an optionally substituted ethylene. In some embodiments, R3 is an optionally substituted propylene. In some embodiments, R3 is (-CH2CH2-). In other embodiments, R3 is (-CH2CH2CH2-). In some embodiments, the optional substitution of R3 is selected from at least one C 1-12 Alkyl, C 1-12 Haloalkyl, halogen, and combinations thereof.

[0069] In some embodiments, the compound is represented by formula (Ia):

[0070]

[0071] In some embodiments, R4, R5, R6 and R7 are each independently selected from -H, halogen, C 1-12 Alkyl and C 1-12 Haloalkyl. In other embodiments, R4, R5, R6 and R7 are each independently selected from -H, CH3-, CH3CH2-, CH3CH2CH2-, CH3CH2CH2CH2-, (CH3)2CH-, CH3CH2CH(CH3)-, (CH3)3C-, -CF3, -CHF2, -CH2F, -CH2CF3, -CH2CHF2, -CH2CH2F, -CH2CH2Cl and -CH2CF2CF3. In certain embodiments, R4, R5, R6 and R7 are each independently selected from -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C- and -CF3.

[0072] In some embodiments, R4 is selected from -H, halogen, C 1-12 Alkyl and C 1-12 In other embodiments, R4 is selected from -H, CH3-, CH3CH2-, CH3CH2CH2-, CH3CH2CH2CH2-, (CH3)2CH-, CH3CH2CH(CH3)-, (CH3)3C-, -CF3, -CHF2, -CH2F, -CH2CF3, -CH2CHF2, -CH2CH2F, -CH2CH2Cl and -CH2CF2CF3. In certain embodiments, R4 is selected from -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C- and -CF3.

[0073] In some embodiments, R5 is selected from -H, halogen, C 1-12 Alkyl and C 1-12 In other embodiments, R5 is selected from -H, CH3-, CH3CH2-, CH3CH2CH2-, CH3CH2CH2CH2-, (CH3)2CH-, CH3CH2CH(CH3)-, (CH3)3C-, -CF3, -CHF2, -CH2F, -CH2CF3, -CH2CHF2, -CH2CH2F, -CH2CH2Cl and -CH2CF2CF3. In certain embodiments, R5 is selected from -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C- and -CF3.

[0074] In some embodiments, R6 is selected from -H, halogen, C 1-12 Alkyl and C 1-12In other embodiments, R6 is selected from -H, CH3-, CH3CH2-, CH3CH2CH2-, CH3CH2CH2CH2-, (CH3)2CH-, CH3CH2CH(CH3)-, (CH3)3C-, -CF3, -CHF2, -CH2F, -CH2CF3, -CH2CHF2, -CH2CH2F, -CH2CH2Cl and -CH2CF2CF3. In certain embodiments, R6 is selected from -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C- and -CF3.

[0075] In some embodiments, R7 is selected from -H, halogen, C 1-12 Alkyl and C 1-12 In other embodiments, R7 is selected from -H, CH3-, CH3CH2-, CH3CH2CH2-, CH3CH2CH2CH2-, (CH3)2CH-, CH3CH2CH(CH3)-, (CH3)3C-, -CF3, -CHF2, -CH2F, -CH2CF3, -CH2CHF2, -CH2CH2F, -CH2CH2Cl and -CH2CF2CF3. In certain embodiments, R7 is selected from -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C- and -CF3.

[0076] In some embodiments, the compound is represented by formula (Ib):

[0077]

[0078] In some embodiments, R8, R9, R 10 , R 11 , R 12 and R 13 are each independently selected from -H, halogen, C 1-12 Alkyl and C 1-12 In some embodiments, R8 is selected from -H, halogen, C 1-12 Alkyl and C 1-12 In some embodiments, R9 is selected from -H, halogen, C 1-12 Alkyl and C 1-12 In some embodiments, R 10 Selected from -H, halogen, C 1-12 Alkyl and C 1-12 In some embodiments, R 11 Selected from -H, halogen, C 1-12 Alkyl and C 1-12 In some embodiments, R12 Selected from -H, halogen, C 1-12 Alkyl and C 1-12 In some embodiments, R 13 Selected from -H, halogen, C 1-12 Alkyl and C 1-12 Halogenated alkyl.

[0079] In some embodiments, the compound of formula (I) can be selected from at least one of the compounds shown in Table 1.

[0080] Table 1

[0081]

[0082]

[0083]

[0084] In some embodiments, the solvent may comprise dimethyl 2,5-dioxadipic acid ester (DMOHC). In some embodiments, the solvent may comprise diethyl 2,5-dioxadipic acid ester (DEOHC). In some embodiments, the solvent may comprise ethyl 2,5-dioxadipic acid ester (EMOHC). In some embodiments, the compound of formula (I) is selected from

[0085]

[0086] In some embodiments, the compound of formula (I) is selected from

[0087] In some embodiments, the solvent may include carbonate. In further embodiments, carbonate may be selected from cyclic carbonates, such as ethylene carbonate (EC), propylene carbonate (PC), vinyl ethylene carbonate (VEC), vinylene carbonate (VC), fluoroethylene carbonate (FEC) and combinations thereof; or non-cyclic carbonates, such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC) and combinations thereof. For example, in some embodiments, the solvent also includes DMC. In some embodiments, the solvent also includes DEC. In some embodiments, the solvent may also include methyl acetate (MA). In some embodiments, the solvent may include ethyl acetate (EA). In some embodiments, the solvent may include propionitrile (PN). In some embodiments, the solvent may include acetonitrile (AN). In some embodiments, the solvent may include gbutyl lactone (GBL).

[0088] Figure 1A shows the phase diagram of a mixture of dimethyl carbonate (DMC) and dimethyl 2,5-dioxaadipate (DMOHC) at different temperatures, and Figure 1B The phase diagram of the mixture of DMC and ethylene carbonate (EC) at different temperatures is shown. Figure 1A and 1B As seen in , the phase diagram of the mixture of DMC and DMOHC is relatively similar to that of the mixture of DMC and EC. Therefore, it can be expected that the two solvent systems will be in the liquid phase at similar temperatures.

[0089] In some embodiments, the electrolyte comprises a total solvent of 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, or 98%. In some embodiments, the electrolyte comprises each solvent of 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, or 98%.

[0090] In some embodiments, the electrolyte comprises one or more solvents. In some embodiments, the electrolyte comprises 1, 2, 3, 4, 5 or 6 solvent systems, or any numerical range therebetween. In some embodiments, the electrolyte comprises a first solvent and a second solvent. In some embodiments, the electrolyte solvent system may comprise a first solvent and a second solvent in a volume ratio of about 10: 1, 9: 1, 8: 1, 7: 1, 6: 1, 5: 1, 4: 1, 3: 1, 2: 1, 1: 1, 1: 2, 1: 3, 1: 4, 1: 4, 1: 6, 1: 7, 1: 8, 1: 9, 1: 10 or any range therebetween. For example, in some embodiments, the volume ratio may be about 3: 7, about 1: 1, about 1: 4, about 4: 1, about 3: 2 or about 2: 3. In some embodiments, the electrolyte further comprises a second solvent selected from ethylene carbonate (EC), propylene carbonate (PC), vinyl ethylene carbonate (VEC), vinylene carbonate (VC), fluoroethylene carbonate (FEC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl acetate (MA), ethyl acetate (EA), propionitrile (PN), acetonitrile (AN), gluorolactone (GBL), and combinations thereof. For example, in some embodiments, the second solvent comprises dimethyl carbonate (DMC). In other embodiments, the second solvent comprises diethyl carbonate (DEC).

[0091] Electrolytes

[0092] The electrolyte formulation described herein may include an alkali metal salt (e.g., a lithium salt and / or a sodium salt) and one or more solvents described herein. Typically, the alkali metal salt includes a cation and an anion. In some embodiments, the anion is redox stable. In some embodiments, the anion may be monovalent. In some embodiments, the cation on the alkali metal salt is selected from Li, Na, K and / or Rb. In some embodiments, the sodium salt may be selected from NaPF6, NaBF4, NaClO4, NaN(FSO2)2(NaFSI), NaB(C2O4)2, and combinations thereof. In some embodiments, the lithium salt may be selected from lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium difluoro(oxalate)borate (LiDFOB), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluoroarsenate (V) (LiAsF6), lithium perchlorate (LiClO4), and combinations thereof. In some embodiments, the lithium salt is LiFSI. In some embodiments, the lithium salt may include an anion selected from hexafluorophosphate, tetrafluoroborate, difluoro(oxalato)borate, bis(fluorosulfonyl)imide, bis(trifluoromethanesulfonyl)imide, hexafluoroarsenate(V), and perchlorate. In certain embodiments, the salt concentration of the electrolyte can be, is, is at, or is at most about 0.1 M, 0.2 M, 0.3 M, 0.4 M, 0.5 M, 0.6 M, 0.7 M, 0.8 M, 0.9 M, 1 M, 1.1 M, 1.2 M, 1.3 M, 1.4 M, 1.5 M, 1.6 M, 1.7 M, 1.8 M, 1.9 M, 2 M, 2.1 M, 2.2 M, 2.3 M, 2.4 M, 2.5 M, 2.6 M, 2.7 M, 2.8 M, 2.9 M, 3 M, 3.1 M, 3.2 M, 3.3 M , 3.4M, 3.5M, 3.6M, 3.7M, 3.8M, 3.9M, 4M, 4.1M, 4.2M, 4.3M, 4.4M, 4.5M, 4.6M, 4.7M, 4.8M, 4.9M, 5M, 5.1M, 5.2M, 5.3M, 5.4M, 5.5M, 5.6M, 5.7M, 5.8M, 5.9M, 6M, 6.1M, 6.2M, 6.3M, 6.4M, 6.5M, 6.6M, 6.7M, 6.8M, 6.9M or 7M, or any range of values ​​therebetween. For example, in some embodiments, the salt concentration may be from about 0.1M to about 5M, from about 0.2M to about 3M, from about 0.3M to about 2M, or from about 0.7M to about 1.5M.

[0093] In some embodiments, the electrolyte further includes one or more additional additives. In some embodiments, the additive can be selected from, for example, vinylene carbonate (VC), ethylene sulfate (DTD), lithium difluorophosphate (LFO), fluoroethylene carbonate (FEC), propylene sulfone (PES), phenyl trifluoromethyl sulfide (PTS), lithium bis (oxalate) borate (LiBOB), lithium difluoro (oxalate) borate (LiDFOB), triethyl borate (TEB), trimethyl borate (TMB), tris-trimethylsilyl borate (TTMSiB), 4-trifluoromethylbenzonitrile (TFMB), tris-trimethylsilyl phosphite (TTSPi), tris-trimethylsilyl phosphate (TTSPi), triethyl phosphite (TEPi), lithium ethoxide (EthOLi), lithium methoxide (MeOLi), lithium tetrafluoro oxalate phosphate (LiTFOP), lithium difluoro dioxalate phosphate (LiDFDOP) and combinations thereof. In some embodiments, the electrolyte comprises each additive in an amount of, about, at most, or at most about 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 7%, or 8% by weight, or any range therebetween. In some embodiments, the electrolyte comprises a plurality of additives in an amount of, about, at most, or at most about 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 11%, or 12% by weight, or any range therebetween.

[0094] Figure 2A and 2B Viscosity versus temperature for a variety of electrolyte solutions and solvent combinations are shown, including 1.0M LiFSI in 80:20DMOHC:DMC; 1.12M LiFSI in DMOC; 1.0M LiPF6 in 3:7EC:DMC; pure DMOHC; pure DEOHC; 3:7EC:DMC; and 80:20DMOHC:DMC. Figure 2A and 2B As shown, the viscosity of pure DMOHC and DEOHC is greater than that of the 3:7EC:DMC and 80:20DMOHC:DMC solvent systems, and the addition of lithium salts generally further increases the viscosity of the electrolyte composition. In addition, it was observed that LiPF6 dissolved in DMOHC at room temperature in about 5 days, and LiFSI dissolved in DMOHC at room temperature faster than LiPF6 (i.e., less than five days). Therefore, Figure 2A and 2B It is suggested that cells containing DMOHC or DEOHC as the sole solvent may need to be operated at elevated temperatures (e.g., at least about 40°C or about 40-85°C) to reduce the viscosity and thereby increase the desired ionic conductivity of the electrolyte. Alternatively, Figure 2A and 2B It was shown that DMOHC and DEOHC can be blended with one or more lower viscosity solvents (eg, DMC or EC:DMC 30:70) to achieve electrolyte viscosities that can be used in energy storage devices operating at room temperature.

[0095] In some embodiments, the viscosity of the electrolyte formulations described herein may be about 1 cP, 2 cP, 3 cP, 4 cP, 5 cP, 6 cP, 7 cP, 8 cP, 9 cP, 10 cP, 11 cP, 12 cP, 13 cP, 14 cP, 15 cP, 16 cP, 17 cP, 18 cP, 19 cP, 20 cP, 21 cP, 22 cP, 23 cP, 24 cP, 25 cP, 26 cP, 27 cP, 28 cP, 29 cP, 30cP, 31cP, 32cP, 33cP, 34cP, 35cP, 36cP, 37cP, 38cP, 39cP, 40cP, 41cP, 42cP, 43cP, 44cP, 45cP, 46cP, 47cP, 48cP, 49cP, 50cP, 51cP, 52cP, 53cP, 54cP, 55cP, 56cP, 57cP, 58cP, 59cP, 60cP, or any value therebetween. For example, about 3cP to about 8cP, 8cP to about 14cP, 14cP to about 20cP, or 20cP to about 55cP.

[0096] Energy storage device

[0097] The energy storage device of the present disclosure includes an electrolyte, a cathode, an anode and a housing discussed herein, wherein the electrolyte, the cathode and the anode are arranged in the housing. In some embodiments, the energy storage device provided herein is a lithium ion battery and / or a sodium ion battery. The cathode and the anode each include an electrode film and a current collector forming an electrode.

[0098] In some embodiments, the electrode films provided herein include at least one active material. In some embodiments, the electrode films further include at least one binder.

[0099] In some embodiments, the electrode film includes an anode active material. In some embodiments, the anode active material may include, for example, an embedded material (e.g., carbon or graphite), an alloy / dealloyed material (e.g., silicon, silicon oxide, tin, and / or tin oxide), a metal alloy or compound (e.g., Si-Al and / or Si-Sn), lithium titanate (LTO), and / or a conversion material (e.g., manganese oxide, molybdenum oxide, nickel oxide, and / or copper oxide). The anode active material may be used alone or mixed together to form a multiphase material (e.g., Si-C, Sn-C, SiOx-C, SnOx-C, Si-Sn, Si-SiOx, Sn-SnOx, Si-SiOx-C, Sn-SnOx-C, Si-Sn-C, SiOx-SnOx-C, Si-SiOx-Sn or Sn-SiOx-SnOx). Anode active materials include common natural graphite, synthetic or artificial graphite, surface-modified graphite, spherical graphite, flake graphite, blends or combinations of these graphites, hard carbon, metal elements and their compounds, and metal-carbon composites for anodes.

[0100] In some embodiments, the electrode film includes an active cathode material. In some embodiments, the cathode active material may include, for example, a metal oxide, a metal sulfide, or an alkali metal oxide (e.g., lithium metal oxide and / or sodium metal oxide). The lithium metal oxide may be, for example, lithium nickel manganese cobalt oxide (NMC), lithium manganese oxide (LMO), lithium iron phosphate (LFP), lithium cobalt oxide (LCO), and / or lithium nickel cobalt aluminum oxide (NCA). In some embodiments, the cathode active material may include, for example, a layered transition metal oxide (e.g., LiCoO2 (LCO), Li(NiMnCo)O2 (NMC), and / or LiNi 0.8 Co 0.15 Al 0.05 O2 (NCA)), spinel manganese oxides (such as LiMn2O4 (LMO) and / or LiMn 1.5 Ni 0.5 O4 (LMNO)), olivine (such as LiFePO4 (LFP), LiMn 1-x Fe x PO4 (LMFP)). The cathode active material may include sulfur or a sulfur-containing material, such as lithium sulfide (Li2S), or other sulfur-based materials, or mixtures thereof. In some embodiments, the sodium metal oxide may be, for example, a layered oxide, a phosphate, and / or a ferrocyanide (e.g., a Prussian white compound). In some embodiments, the sodium metal oxide may be, for example, NaFe 0.5 Mn 0.5 O2、NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3O2, NaFe2(CN)6, Na2VOPO4F, NaMnO2 and / or NaFe 0.3 Mn 0.5 Cu 0.2 O2.

[0101] The energy storage device provided herein can be any suitable configuration, such as a plane, a spiral winding, a button shape or a bag shape. The energy storage device provided herein can be a component of a system, such as a power generation system, an uninterruptible power supply system (UPS), a photovoltaic power generation system, an energy recovery system for, for example, industrial machinery and / or transportation. The energy storage device provided herein can be used to power various electronic devices and / or motor vehicles (including hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV) and / or electric vehicles (EV)).

[0102] In some embodiments, an energy storage device comprising an electrolyte formulation as provided herein may exhibit a higher discharge rate capability relative to a comparative energy storage device. This higher discharge rate capability is ideal in high energy, high power applications such as electric vehicle propulsion. In some embodiments, an energy storage device comprising an electrolyte formulation as provided herein may exhibit improved cycling stability at abnormally high temperatures (e.g., at least about 70° C. or about 70-85° C.).

[0103] Energy storage devices comprising the electrolyte formulations described herein may be characterized by improved capacity retention during device life. Further improvements that may be achieved in various embodiments include improved cycling performance, including improved storage stability and reduced capacity fade during cycling. In some embodiments, improved cycling performance is also achieved at abnormally high temperatures (e.g., at least about 70°C or about 70-85°C). In some embodiments, the energy storage device is configured to operate at, about, at least, or at least about 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 95°C, 100°C, 105°C, or any range of values ​​therebetween. For example, 20°C to 30°C, 70°C to 85°C, 20°C to 85°C, or 50°C to 85°C. In some embodiments, the energy storage device is configured to operate at or to about 2.5V, 2.6V, 2.7V, 2.8V, 2.9V, 3V, 3.1V, 3.2V, 3.3V, 3.4V, 3.5V, 3.6V, 3.7V, 3.8V, 3.9V, 4V, 4.1V, 4.2V, 4.3V, 4.4V or 4.5V, or any range of values ​​therebetween. For example, 2.5V to 4.5V, 3.0V to 4.2V, 4.1V to 4.3V, 2.5V to 3.7V, 3.3V to 3.4V, 3.0V to 4.3V, or 3V to 3.8V. In further embodiments, the lithium ion battery pack is configured to have a minimum operating voltage of about 2.5V to about 3V, respectively. In still further embodiments, the lithium-ion batteries are configured to have a maximum operating voltage of about 3.8V to about 4.4V, respectively.

[0104] In some embodiments, the energy storage device has at least 99%, 98%, 97%, 96%, 95%, 94%, 93%, 92%, 91%, 90%, 89%, 88%, 87%, 86%, 85%, 84%, 83%, 82%, 81%, 80%, or any range of values ​​therebetween, after 2,000 hours of cycling at an operating temperature of at least 70° C. For example, 99% to 90%, 99% to 95%, 98% to 91%, or 90% to 85%.

[0105] In some embodiments, the electrolyte formulations described herein may advantageously exhibit improved performance relative to typical electrolyte formulations. Performance may be related to, for example, coulombic efficiency, voltage polarization, capacity, and / or conductivity. Voltage polarization is the difference (ΔV) between the average charge and discharge voltages of a battery. Therefore, a smaller ΔV value may indicate a smaller polarization and a lower impedance in the battery. Therefore, an increase in ΔV with the number of cycles may indicate an increase in impedance during the cycle. The first charge and discharge (i.e., "formation process") of the energy storage device may be performed by the manufacturer in the factory. Therefore, in order to simplify the manufacturing process, it is advantageous to minimize gas generation during the formation process. Charge transfer resistance is an indicator of the degree of difficulty encountered when electrons and lithium ions move as lithium atoms to the anode or cathode material during the operation of a lithium-ion battery. Therefore, the greater the measured value of the charge transfer resistance, the more energy is lost during the charge transfer process.

[0106] In some embodiments, an energy storage device as provided herein may have a discharge capacity retention of at least about 99%, 98%, 97%, 96%, 95%, 94%, 93%, 92%, 91%, 90%, 89%, 88%, 87%, 86%, 85%, 84%, 83%, 82%, 81%, 80%, or any range of values ​​therebetween after at least about 500 hours of cycling when cycled between 2.5V and 4.5V or between 2.5V and 4.3V at an operating temperature of at least 70°C. In some embodiments, the energy storage devices provided herein can have at least about 80% discharge capacity retention after cycling for at least about 500 hours at an operating temperature of at least 70°C when cycled between 2.5V, 2.6V, 2.7V, 2.8V, 2.9V, 3V, 3.1V, 3.2V, 3.3V, 3.4V, 3.5V, 3.6V, 3.7V, 3.8V, 3.9V, 4V, 4.1V, 4.2V, 4.3V, 4.4V or 4.5V, or any range of values ​​therebetween. In some embodiments, when cycled between 2.5V and 4.5V at an operating temperature of at least 70°C, an energy storage device as provided herein can be used for at least 500 hours, 600 hours, 700 hours, 800 hours, 900 hours, 1,000 hours, 1,100 hours, 1,200 hours, 1,300 hours, 1,400 hours, 1,500 hours, 1,600 hours, 1,700 hours, 1,800 hours. , 1,900 hours, 2,000 hours, 2,100 hours, 2,200 hours, 2,300 hours, 2,400 hours, 2,500 hours, 2,600 hours, 2,700 hours, 2,800 hours, 2,900 hours, 3,000 hours, 3,500 hours, 4,000 hours, 4,500 hours, 5,000 hours, or any range therebetween. In some embodiments, the energy storage devices provided herein have at least 80% discharge capacity retention after at least about 500 hours of cycling when cycled between 2.5V and 4.5V at an operating temperature of at least 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 95°C, 100°C, 105°C, or a range of any values ​​therebetween.

[0107] It should be understood that the electrolyte formulations provided herein can be used in various embodiments of any of a variety of energy storage devices and systems, such as one or more batteries, capacitors, capacitor-battery hybrids, fuel cells or other energy storage systems or devices and combinations thereof. In some embodiments, the electrolyte additive or an electrolyte comprising the additive described herein can be implemented in a lithium ion battery and / or a sodium ion battery.

[0108] Preparation method

[0109] Some embodiments of the present disclosure relate to methods for preparing energy storage devices disclosed herein. In some embodiments, the method for preparing an energy storage device comprises: providing a cathode, an anode, a separator provided between the cathode and the anode, and an electrolyte in a housing. In some embodiments, the electrolyte comprises a solvent and an alkali metal salt. The solvent comprises a compound shown in formula (I) as described herein.

[0110] Example

[0111] Exemplary embodiments of the present disclosure, including methods, materials, and / or resulting products, are described in the following examples.

[0112] Example 1 - Initial Cycle Matrix

[0113] like Figure 3 As shown, compared to the standard electrolyte system using 25:5:70EC:EMC:DMC (ie "EED") as the solvent system, the battery using dimethyl 2,5-dioxaadipate (DMOHC) as the only solvent and 2% vinylene carbonate (VC) as an additive provided impressive results. As the initial cycle matrix, the normalized discharge capacity of the NMC532 / artificial graphite battery was tested for the relationship between the cycle time. Figure 3 The normalized discharge capacity versus cycle time for NMC532 / artificial graphite cells with different lithium salts and additives tested at an operating temperature of 70°C and an operating voltage of 4.3V are shown, including:

[0114] (a) LiPF6 in 25:5:70EC:EMC:DMC with 2% vinylene carbonate (VC) and 1% ethylene sulfate (DTD) cycled with a continuous 3 h charge and discharge schedule (C / 3) with 20 h charge and discharge cycles every 50 cycles (two examples of “EED LiPF6 c / 32VC+1DTD”) (i.e., “control”);

[0115] (b) LiPF6 in pure dimethyl 2,5-dioxaadipate (DMOHC) with 2% VC cycled with a continuous 20 h charge and discharge schedule (C / 20) (“LiPF6 C / 20”);

[0116] (c) LiPF6 in pure DMOHC with 2% VC cycled with a continuous 10 h charge and discharge schedule (C / 10) (“LiPF6 C / 10”);

[0117] (d) LiFSI in pure DMOHC with 2% VC and C / 10 cycle (“LiFSI C / 10”); and

[0118] (e) LiFSI in pure DMOHC with 2% VC and C / 20 cycle (“LiFSI C / 20”).

[0119] like Figure 3 As shown, the normalized discharge capacity versus cycle time relationship of the cell with LiFSI in pure DMOHC provides superior capacity retention during C / 10 and C / 20 compared to the control electrolyte. For example, the normalized capacity of the cell with DMOHC and LiFSI is about 90% after 6,000 cycle hours, while the normalized capacity of the standard electrolyte system using 25:5:75 EC:EMC:DMC as solvent reaches the same capacity after about 2,000 cycle hours.

[0120] Example 2 - LFP / PG battery with DMOHC and mixed blends

[0121] like Figure 4 As shown, lithium iron phosphate (ie, "LFP") cells using pure graphite (ie, "PG") as the negative electrode exhibited the greatest C / 20 capacity retention when operated with LiFSI, 2% VC, and 1% DTD at 70°C. LFP / PG cells with DMOHC and mixed blends were tested at 70°C and C / 20 cycles. Figure 4 The normalized discharge capacity versus cycle time and voltage polarization versus cycle time of LFP / PG cells with different lithium salts and additives are shown, including:

[0122] (a) LiFSI in pure DMOHC with 2% VC and 1% DTD, and C / 20 cycle (“DMOHC_LiFSI_2VC_1DTD”);

[0123] (b) LiPF6 in pure DMOHC with 2% VC and C / 20 cycle (“DMOHC_LiPF6_2VC”);

[0124] (c) LiFSI in pure DMOHC with 2% fluoroethylene carbonate (FEC), and C / 20 cycle (“DMOHC_LiFSI_2FEC”);

[0125] (d) LiFSI in pure DMOHC with 2% VC and C / 20 cycle (“DMOHC_LiFSI_2VC”);

[0126] (e) LiFSI in 3:7EC:DMC with 2% VC and C / 3 cycle ("EC:DMC 3:7LIPF6 2VC(C / 3)") (ie, "Control 1"); and

[0127] (f) LiPF6 in 3:7EC:DMC with 2% VC and C / 3 cycle ("EC:DMC 3:7LIPF6 2VC(C / 3)") (ie, "Control 2").

[0128] Figure 5 The relationship between the normalized discharge capacity and the cycle time and the voltage polarization and the cycle time of the LFP / PG battery with different amounts of DMOHC electrolyte system is shown, including:

[0129] (a) LiFSI in 5 vol% DMOHC and 95 vol% 3:7EC:DMC with 2% VC and 1% DTD, and C / 20 cycling (“EC:DMC 3:7LIFSI 2VC1DTD 5DMOHC”);

[0130] (b) LiFSI in 10 vol% DMOHC and 90 vol% 3:7EC:DMC with 2% VC and 1% DTD, and C / 20 cycling (“EC:DMC 3:7LIFSI 2VC 1DTD 10DMOHC”);

[0131] (c) LiFSI in 30 vol% DMOHC and 70 vol% 3:7EC:DMC with 2% VC and 1% DTD, and C / 20 cycling (“EC:OMC 3:7LIFSI 2VC 1DTD 30DMOHC”);

[0132] (d) LiFSI in 60 vol% DMOHC and 40 vol% 3:7EC:DMC with 2% VC and 1% DTD, and C / 20 cycling (“EC:DMC 3:7LIFSI 2VC 1DTD 60DMOHC”); and

[0133] (e) LiPF6 in 3:7EC:DMC with 2% VC and C / 3 cycle ("EC:DMC 3:7LIPF6 2VC(C / 3)") (ie, "Control 2"); and

[0134] (f) LiFSI in 3:7EC:DMC with 2% VC and C / 3 cycle (“EC:DMC 3:7LIFSI 2VC(C / 3)”) (ie, “Control 1”).

[0135] like Figure 4 As shown, the battery with pure DMOHC and further electrolyte containing additive VC or 2% VC + 1% DTD provides relatively best capacity retention. Figure 5 As shown, the cell with electrolyte containing a blend of DMOHC and EC:DMC at 60:40 provided relatively the best capacity retention. Control electrolytes 1 and 2 containing only co-solvent EC:DMC 3:7 resulted in poor capacity retention.

[0136] Example 3 - Post-formation matrix of a cell containing DMOHC and DEOHC

[0137] like Figures 6A-6C As shown in Figure 2, blending DMOHC with DMC in lithium iron phosphate batteries reduces the impedance (R ct and ΔV), and reduced gas generation after the formation process performed at 40°C and C / 20. Figures 6A-6C Impedance and gas generation data for electrolyte formulations are shown, including:

[0138] (a) 1M LiFSI in pure DMOHC with 2% VC + 1% DTD (“DMOHC, 1M LIFSI”);

[0139] (b) 1M LiPF6 in pure DMOHC with 2% VC + 1% DTD (“DMOHC, 1M LiPF6”);

[0140] (c) 1M LiFSI in diethyl 2,5-dioxadipic acid (DEOHC) with 2% VC + 1% DTD (“DEOHC, 1M LiFSI”);

[0141] (d) 1M LiFSI in 40:60DMOHC:DMC with 2% VC+1% DTD (“DMOHC:DMC 40:60, 1MLiFSI”);

[0142] (e) 1M LiFSI in 20:80DMOHC:DMC with 2% VC + 1% DTD ("DMOHC:DMC 20:80, 1MLiFSI"); and

[0143] (f) 1M LiFSI in 30:70 EC:DMC with 2% VC+1% DTD (“EC:DMC 30:70, 1MLiFSI”).

[0144] like Fig. 6A and 6B As shown, the charge transfer resistance of the lithium iron phosphate battery with 60% DMC provides improved results and reduced impedance when compared with batteries with pure DMOHC or pure DEOHC. Similarly, the lithium iron phosphate battery with LiFSI in 60% DMC and 40% DMOHC forms less gas than the lithium iron phosphate battery with LiFSI in pure DMOHC. Figure 6C It was shown that cells with LiPF6 in pure DMOHC provided improved results in terms of gas generation compared to cells with LiFSI in pure DMOHC. In addition, cells with at least 60% DMC provided improved gas generation results when compared to cells with pure DMOHC or pure DEOHC.

[0145] Example 4 - Microcalorimetry and parasitic heat flow on LFP cells

[0146] Figure 7 Shows the use of Figures 6A-6C The relationship between the average parasitic heat flow and the cycle number of LFP / PG cells with the same electrolyte formulation. Figure 7 As shown, the minimum parasitic heat flux in the microcalorimetry experiment is similar to Figure 4 The best cycle life of the pure DMOHC battery shown is matched. The mixed blend of solvents provides improved parasitic heat flow results compared to the control electrolyte containing 30:70 EC:DMC. Therefore, blending 20%-40% DMOHC with DMC provides the best compromise between formation performance and cycling performance.

[0147] Example 5 - Normalized discharge capacity in LFP cells with DMOHC and hybrid blends

[0148] Figure 8 The normalized discharge capacity versus cycle time for LFP / PG cells tested at an operating temperature of 70°C is shown, including:

[0149] (a) 1M LiFSI in pure DMOHC with 2% VC and 1% DTD (“DMOHC, 1M LiFSI, 2VC 1DTD”);

[0150] (b) 1M LiFSI in 40:60DMOHC:DMC with 2% VC and 1% DTD (“DMOHC:DMC 40:60, 1MLiFSI, 2VC 1DTD”);

[0151] (c) 1M LiFSI in 20:80DMOHC:DMC with 2% VC and 1% DTD (“DMOHC:DMC 20:80, 1MLiFSI, 2VC 1DTD”);

[0152] (d) 1M LiPF6 in pure DMOHC with 2% VC and 1% DTD (“DMOHC, 1M LiPF6, 2VC 1DTD”);

[0153] (e) 1M LiFSI in pure DMOHC with 2% VC and 1% DTD (“DEOHC, 1M LIFSI, 2VC 1DTD”); and

[0154] (f) 1.5M LiPF6 in 30:70 EC:DMC with 2% VC ("EC:DMC 30:70, 1.5M LiPF6, 2VC") (ie, "Control").

[0155] like Figure 8 As shown, cells containing DMOHC and 20% or 40% DMC provide improved capacity retention compared to the control. Cells containing pure DMOHC or DEOHC also provide improved capacity results compared to the control. For example, the normalized discharge capacity of the lithium iron phosphate cell with pure DMOHC exceeded 92% after 3,750 cycle hours, while the normalized capacity of the control electrolyte system after 3,750 cycle hours was about 86%. Therefore, all cells with DMOHC or DEOHC provide improved capacity retention relative to the control electrolyte system.

[0156] Example 6 - Capacity Retention in LFP / PG Cells with DMOHC and Hybrid Blends

[0157] like Fig. 9 As shown, blending DMOHC with DMC resulted in improved capacity retention compared to the control electrolyte. Fig. 9 The normalized discharge capacity versus cycle time for LFP / PG cells tested at an operating temperature of 70°C is shown, including:

[0158] (a) LiFSI in 80:20DMOHC:DMC with 2% VC and 1% DTD, and C / 20 cycle (“LFP DMOHC80DMC 20LIFSI 2VC 1DTD”);

[0159] (b) LiFSI in 60:40DMOHC:DMC with 2% VC and 1% DTD, and C / 20 cycle (“LFP DMOHC60DMC 40LIFSI 2VC 1DTD”);

[0160] (c) LiFSI in 40:60DMOHC:DMC with 2% VC and 1% DTD, and C / 20 cycle (“LFP DMOHC40DMC 60LIFSI 2VC 1DTD”);

[0161] (d) LiFSI in 20:80DMOHC:DMC with 2% VC and 1% DTD, and C / 20 cycle (“LFP DMOHC20DMC 80LIFSI 2VC 1DTD”);

[0162] (e) LiFSI in pure DMOHC with 2% VC and 1% DTD, and C / 20 cycling (“LFP DMOHC LiFSI2VC 1DTD (data cutoff)”); and

[0163] (f) LiFSI in 3:7EC:DMC with 2% VC, and C / 3 cycle ("LFP EC:DMC 3:7LIFSI 2VCC / 3 Cycle (Data Cutoff)") (ie, "Control").

[0164] Fig. 9 The performance benefits of batteries with electrolyte systems containing DMOHC and at least 20% DMC compared to control electrolyte systems were confirmed. Batteries containing 40% DMOHC and 60% DMC provided the best cycling performance in the mixed DMOHC / DMC electrolyte system. Batteries with 100% DMOHC provided the best cycling results relative to mixed DMOHC / DMC electrolyte systems and controls.

[0165] Example 6 - Circulating matrix with DEOHC

[0166] Fig.10 The normalized discharge capacity versus cycle time for NMC532 / artificial graphite (ie, "AML") cells tested between 3.0V and 4.3V at an operating temperature of 70°C is shown, including:

[0167] (a) LiFSI in DEOHC with 2% VC and C / 20 cycles between 3.0 V and 4.3 V (“DEOHC_LiFSI_2VC C / 20”);

[0168] (b) LiFSI in DEOHC with 2% VC and 1% DTD, and C / 20 cycles between 3.0 V and 4.3 V (“DEOHC_LiFSI_2VC_1DTD C / 20”); and

[0169] (c) LiFSI in DMOHC with 2% VC and C / 20 cycles between 3.0 V and 4.3 V (“LIFSIDMOHC C / 20”).

[0170] Fig.11 The normalized discharge capacity versus cycle time for LFP / PG cells tested at an operating temperature of 70°C is shown, including:

[0171] (a) LiFSI in DEOHC with 2% VC and C / 20 cycles between 2.5 V and 3.65 V (“DEOHC_LiFS1_2VC C / 20”);

[0172] (b) LiFSI in DEOHC with 2% VC and 1% DTD, and C / 20 cycles between 2.5 V and 3.65 V (“DEOHC_LiFSl_2VC 1DTD C / 20”);

[0173] (c) LiFSI in DMOHC with 2% VC and 1% DTD, and C / 20 cycles between 2.5 V and 3.65 V (“DMOHC_LiFSl_2VC_1DTD C / 20”); and

[0174] (d) LiFSI in 3:7EC:DMC with 2% VC and C / 3 cycles between 2.5 V and 3.65 V (“EC:DMC_3:7_15M LIFSI LFPC / 3”) (ie, “Control”).

[0175] like Fig.10 As shown in Figure 2, NMC532 / artificial graphite cells with DMOHC and DEOHC showed similar capacity retention performance. Fig.11 As shown, among the cells using LFP / PG, the cells with DMOHC performed better relative to the cells containing DEOHC and the control. The LFP / PG cells with DEOHC showed improved results compared to the control cells.

[0176] Example 8 - Capacity Retention in LFP / PG Cells Operated with DEOHC and DMC

[0177] Fig.12 The normalized discharge capacity versus cycle time for LFP cells tested at an operating temperature of 70°C is shown, including:

[0178] (a) LiFSI in 80:20DEOHC:DMC with 2% VC and 1% DTD and C / 20 cycle (“LFP / pure graphite DEOHC 80DMC 20LiFSI 2VC 1DTD C / 20”);

[0179] (b) LiFSI in 60:40DEOHC:DMC with 2% VC and 1% DTD and C / 20 cycle (“LFP / pure graphiteDEOHC 60DMC 40LiFSI 2VC 1DTD C / 20”);

[0180] (c) LiFSI in 40:60DEOHC:DMC with 2% VC and 1% DTD and C / 20 cycle (“LFP / pure graphite DEOHC 40DMC 60LiFSI 2VC 1DTD C / 20”);

[0181] (d) LiFSI in 20:80DEOHC:DMC with 2% VC and 1% DTD and C / 20 cycle (“LFP / pure graphite DEOHC 20DMC 80LiFSI 2VC 1DTD C / 20”);

[0182] (e) LiFSI in pure DMOHC with 2% VC and 1% DTD and C / 20 cycles (“LFP / pure graphite DMOHCLiFSI 2VC 1DTD (data cutoff) C / 20”);

[0183] (f) LiFSI in 3:7EC:DMC with 2% VC and C / 3 cycle ("LFP / pure graphite EC:DMC 3:7LIFSI2VC C / 3 cycle (data cutoff)") (ie, "Control"); and

[0184] (g) LiFSI in pure DEOHC with 2% VC and 1% DTD and C / 20 cycle (“LFP / pure graphite DEOHCLiFSI 2VC 1DTD C / 20”).

[0185] like Fig.12 As shown in Figure 2, the normalized discharge capacity of the lithium iron phosphate battery with DEOHC:DMC mixture at 70°C exceeded 93% after 2,000 cycle hours. Similar results were observed for the lithium iron phosphate battery using pure DMOHC after 2,000 cycle hours. In contrast, the normalized capacity of the control electrolyte system using EC:DMC 3:7 at 70°C was only about 91% after 2,000 cycle hours.

[0186] Example 9 - NMC532 / synthetic graphite cell balanced to 3.8V with DMOHC

[0187] like Fig.13A and 13B As shown, the cell with the electrolyte system comprising DMOHC and LiFSI with 2% VC and 1% DTD showed incredible capacity retention when tested at 70°C. Fig.13Ashows the normalized discharge capacity versus cycle time for an NMC532 / artificial graphite (ie, "AML") cell balanced to 3.8V, and Fig. 13B The relationship between voltage polarization and cycle time is shown, including:

[0188] (a) LiFSI in pure DMOHC with 2% VC (“DMOHC_LiFSI_2VC”);

[0189] (b) LiFSI in pure DMOHC with 2% VC and 1% DTD (“DMOHC_LiFSI_2VC_1DTD”); and

[0190] (c) LiPF6 in pure DMOHC with 2% VC and 1% DTD (“DMOHC_LiPF6_2VC_1DTD”).

[0191] Fig.14 The charge and discharge capacity versus cycle time of NMC532 / artificial graphite cells tested at an operating temperature of 70°C are shown, including LiFSI in pure DMOHC with 2% VC and 1% DTD (“DMOHC LIFSI 2VC 1DTD (charge)” and “DMOHC LIFSI 2VC 1DTD (discharge)”, respectively).

[0192] like Fig.13A As shown in Figure 2, the normalized capacity of the NMC532 / artificial graphite battery with DMOHC and LiFSI is about 99% after about 3,500 cycle hours. Fig. 13B As shown, the smallest voltage polarization increase with test time was observed in the NMC532 / artificial graphite cell containing LiFSI in pure DMOHC with 2% VC and the NMC532 / artificial graphite cell with LiFSI in pure DMOHC with 2% VC and 1% DTD. Fig.14 As shown, the smallest difference between charge and discharge capacity was observed in the NMC532 / artificial graphite cell with LiFSI in pure DMOHC with 2% VC and 1% DTD. This represents a coulombic efficiency of about 99.8% for a 40-hour charge-discharge cycle at a temperature of 70°C.

[0193] Example 10 - NMC532 / synthetic graphite cell balanced to 3.8V with DMOHC

[0194] like Fig.15 As described, encouraging results were obtained with DMOHC mixed with DMC in NMC532 / artificial graphite (ie, "AML") cells. Fig.15The normalized discharge capacity versus cycle time for NMC532 / synthetic graphite cells balanced to 3.8V tested at an operating temperature of 70°C is shown, including:

[0195] (a) LiFSI in 80:20DMOHC:DMC with 2% VC and 1% DTD, and C / 20 cycle (“LiFSI80DMOHC 20DMC 2VC 1DTD C / 20”);

[0196] (b) LiFSI in 60:40DMOHC:DMC with 2% VC and 1% DTD, and C / 20 cycle (“LiFSI60DMOHC 40DMC 2VC 1DTD C / 20”);

[0197] (c) LiFSI in 40:60DMOHC:DMC with 2% VC and 1% DTD, and C / 20 cycling (“LiFSI40DMOHC 60DMC 2VC 1DTD C / 20”);

[0198] (d) LiFSI in 20:80DMOHC:DMC with 2% VC and 1% DTD, and C / 20 cycling (“LiFSI20DMOHC 80DMC 2VC 1DTD C / 20”); and

[0199] (e) LiFSI in pure DMOHC with 2% VC and 1% DTD, and C / 20 cycle (“LiFSIDMOHC 2VC1DTD C / 20”).

[0200] like Fig.15 As shown, mixed blend ratios of solvents, such as 40% DMOHC and 60% DMC; 60% DMOHC and 40% DMC; or 80% DMOHC and 20% DMC all provided similar results, with normalized capacities exceeding 99% after about 2,000 cycle hours. The best cycle life results were observed in cells with pure DMOHC.

[0201] Example 11 - Cycling substrate at 85°C

[0202] Fig.16 The normalized discharge capacity versus cycle time and voltage polarization versus cycle time for a lithium iron phosphate (ie, "LFP") battery at an operating temperature of 85°C are shown, including:

[0203] (a) LiFSI in 3:7EC:DMC with 2% VC and 1% DTD, and C / 3 cycling at 3.65 V (“LFP / PGEC:DMC 3:7LIFSI 2VC 1DTD 3.65VC / 3”) (ie, “Control 1”); and

[0204] (b) LiFSI in pure DMOHC with 2% VC and 1% DTD, and C / 20 cycles at 3.65 V (two examples of “LFP / PGDMOHC LIFSI 2VC 1DTD 3.65VC / 20”).

[0205] Fig.17 The normalized discharge capacity versus cycle time and voltage polarization versus cycle time for NMC532 / artificial graphite ("AML") cells at an operating temperature of 85°C are shown, including:

[0206] (a) LiFSI in 3:7EC:DMC with 2% VC and 1% DTD, and C / 3 cycling at 3.8 V (two examples of “NMC532 / SAF EC:DMC 3:7LIFSI 2VC 1DTD 3.8VC / 3”) (i.e., “Control 2”);

[0207] (b) LiFSI in pure DMOHC with 2% VC and 1% DTD, and C / 20 cycles at 3.8 V (two examples of “NMC532 / SAF DMOHC LIFSI 2VC 1DTD 3.8VC / 20”); and

[0208] (c) LiFSI in 1:1 DMOHC:DMC with 2% VC and 1% DTD, and C / 20 cycles at 3.8 V (two examples of “NMC532 / SAF DMOHC:DMC 1:1 LIFSI 2VC 1DTD 3.8VC / 20”).

[0209] Fig.18 The results show that Ni83 / PG (Ni83 is LiNi purchased from Xiamen Tungsten Company (XTC, China)) at an operating temperature of 85°C. 0.83 Mn 0.11 Co 0.06 O2) The relationship between the normalized discharge capacity of the battery and the cycle time and the voltage polarization and the cycle time, including:

[0210] (a) LiFSI in 3:7EC:DMC with 2% VC and 1% DTD, and C / 3 cycling at 3.9 V (two examples of “Ni83 / PGEC:DMC 3:7LIFSI 2VC 1DTD 3.9VC / 3”) (i.e., “Control 3”);

[0211] (b) LiFSI in pure DMOHC with 2% VC and 1% DTD, and C / 20 cycles at 3.9 V (two examples of “Ni83 / PGDMOHC LIFSI 2VC 1DTD 3.9VC / 20”); and

[0212] (c) LiFSI in 1:1 DMOHC:DMC with 2% VC and 1% DTD, and C / 20 cycles at 3.9 V (two examples of “Ni83 / PG DMOHC:DMC 1:1 LIFSI 2VC1DTD 3.9VC / 20”).

[0213] LFP / PG cells using DMOHC as the sole solvent showed improved results over LFP / PG cells using 3:7EC:DMC as the solvent system. NMC532 / artificial graphite cells using DMOHC as the sole solvent performed comparable to cells using 1:1DMOHC and DMC during 20 hours of charge and discharge cycles at 85°C. For example, the normalized capacity of NMC532 / artificial graphite cells balanced to 3.8V at 85°C using DMOHC or 1:1DMOHC:DMC was about 99% after 700 cycle hours, while the normalized capacity of the standard electrolyte system using 3:7EC:DMC as the solvent reached the same capacity after about 400 cycle hours. Similar results were observed in Ni83 / PG cells. The normalized capacity of Ni83 / PG cells at 85°C using DMOHC or 1:1DMOHC:DMC was about 98% after 700 cycle hours. In contrast, the normalized capacity of the Ni83 / PG cells at 85°C using 3:7EC:DMC as solvent reaches the same capacity after about 300 cycle hours. Some cells have been tested for longer periods of up to 1400 hours and continue to show similarly impressive results.

[0214] Example 12 - Ni83 / PG battery with DEC as co-solvent

[0215] Fig.19 The relationship between the discharge capacity and the cycle time and the normalized discharge capacity of the Ni83 / PG battery at the C / 3 cycle (wherein a C / 20:C / 20 cycle is performed every 50 cycles) at an operating temperature of 85°C is shown, including:

[0216] (a) 1M LiFSI in 20:80DMOHC:DEC with 2% VC and 1% DTD at 3.8 V (“20DMOHC80DEC 2VC 1DTD 3.8 V”);

[0217] (b) 1M LiFSI in 20:80DMOHC:DEC with 2% VC and 1% DTD at 3.9V (“20DMOHC80DEC 2VC 1DTD 3.9V”);

[0218] (c) 1M LiFSI in 20:80DMe-DMOHC:DEC with 2% VC and 1% DTD at 3.9 V (“20DMe80DEC 2VC 1DTD 3.9 V”);

[0219] (d) 1M LiFSI in 20:80DMe-DMOHC:DEC with 2% VC and 1% DTD at 3.8V (“20DMe80DEC 2VC 1DTD 3.8V”); and

[0220] (e) 1M LiFSI in 20:80Me-DMOHC:DEC with 2% VC and 1% DTD at 3.9 V (“20MeDMOHC80DEC 2VC 1DTD 3.9 V” and “20MeDMOHC 80DEC 2VC 1DTD 3.9 V”).

[0221] like Fig.19 As shown, the mixed blend ratio of 20% Me-DMOHC and 80% DEC cycled at 3.9 V provided similar results to 20% DMOHC and 80% DEC when cycled at 3.8 V and 3.9 V. In addition, Fig.19 It is shown that DMOHC, Me-DMOHC and DMe-DMOHC can be blended with diethyl carbonate (DEC) and used in lithium-ion batteries operating at 85 °C.

[0222] Example 13 - Ni83 / PG Cells Tested at 3.9V with DMOHC and DEC

[0223] Fig. 20A The relationship between the discharge capacity and the cycle time and the normalized discharge capacity and the cycle time of the Ni83 / PG battery at an operating temperature of 20°C is shown, including:

[0224] (a) 1M LiFSI in 20:80DMOHC:DEC with 2% VC and 1% DTD at 3.9 V for 388 cycles (two examples of “DMOHC:DEC 2:8 2VC 1DTD (388 cycles)”).

[0225] The cells were cycled at C / 3 with C / 20 charging followed by C / 20, C / 10, C / 5, C / 2 and C discharges every 50 cycles.

[0226] Fig. 20B The relationship between the discharge capacity and the cycle time and the normalized discharge capacity and the cycle time of the Ni83 / PG battery at an operating temperature of 85°C is shown, including:

[0227] (a) 1M LiFSI in 20:80DMOHC:DEC with 2% VC and 1% DTD at 3.9 V for 380 cycles (“DMOHC:DEC 2:8 2VC 1DTD (380 cycles)”); and

[0228] (b) 1M LiFSI in 20:80 DMOHC:DEC with 2% VC and 1% DTD at 3.9 V for 385 cycles (“DMOHC:DEC 2:8 2VC 1DTD (385 cycles)”).

[0229] The cells were cycled at C3. Every 50 cycles, a single C / 20:C / 20 cycle was performed.

[0230] like Fig. 20A As shown, a Ni83 / PG battery containing a mixed blend ratio of 20% DMOHC and 80% DEC cycled at 3.9 V at an operating temperature of 20° C. retains more than 99% of the initial capacity after about 2500 cycle hours. Fig. 20B As shown, a Ni83 / PG battery containing a mixed blend ratio of 20% DMOHC and 80% DEC cycled at 3.9 V at an operating temperature of 85°C retains more than 90% of the initial capacity after about 2500 cycle hours. Fig. 20A and 20B As shown, the electrolyte with a solvent blend of DMOHC and DEC operates favorably at C / 3 with a nickel-rich cathode (such as Ni83) at both 20°C and 85°C.

[0231] Example 14 - NMC640 / PG Cells Tested at 3.9V with DMOHC and DEC

[0232] Fig.21A The relationship between the discharge capacity and cycle time of the NMC640 battery and the normalized discharge capacity and cycle time are shown, including:

[0233] (a) 1M LiFSI in 20:80DMOHC:DEC with 2% VC and 1% DTD at 3.9 V for 273 cycles (“DMOHC:DEC 2:8 2VC 1DTD (273 cycles)”); and

[0234] (b) 1M LiFSI in 20:80 DMOHC:DEC with 2% VC and 1% DTD at 3.9 V for 273 cycles (“DMOHC:DEC 2:8 2VC 1DTD (338 cycles)”).

[0235] The cells were cycled at C / 3 at an operating temperature of 20°C, with C / 20 charging followed by C / 20, C / 10, C / 5, C / 2 and C discharge every 50 cycles.

[0236] Fig.21B The relationship between the discharge capacity and cycle time of the NMC640 / PG battery and the normalized discharge capacity and cycle time are shown, including:

[0237] (a) 1M LiFSI in 20:80 DMOHC:DEC with 2% VC and 1% DTD at 3.9 V for 365 cycles (“DMOHC:DEC 2:8 2VC 1DTD (365 cycles)”).

[0238] The cells were cycled at C / 3 at an operating temperature of 85°C with a single C / 20:C / 20 cycle every 50 cycles. Fig.21A As shown, NMC640 / PG cells containing a mixed blend ratio of 20% DMOHC and 80% DEC cycled at 3.9 V at an operating temperature of 20° C. retain more than 99% of the initial capacity after about 2500 cycle hours. Fig.21B As shown, NMC640 / PG cells containing a mixed blend ratio of 20% DMOHC and 80% DEC cycled at 3.9 V at an operating temperature of 85°C retain more than 90% of the initial capacity after about 2500 cycle hours. Fig.21A and 21B As shown, the electrolyte with the solvent blend of DMOHC and DEC operates advantageously at C / 3 with a cobalt-free cathode such as NMC640 at both 20°C and 85°C.

[0239] Example 15 - Ni83 / PG cells tested at 3.8V and 3.9V with DMOHC and DEC

[0240] Fig.22A The discharge capacity versus cycle time and the normalized discharge capacity versus cycle time for Ni83 / PG cells tested at 3.8V at an operating temperature of 85°C are shown, including:

[0241] (a) 1M LiFSI in 20:80DMOHC:DEC with 2% VC and 1% DTD (two examples of “DMOHC:DEC 2:8 2VC1DTD”); and

[0242] (b) 1M LiFSI in 1:1 EC:DEC with 2% VC and 1% DTD (“EC:DEC 1:1 2VC 1DTD (Exhaust Cycle 350)” and “EC:DEC 1:1 2VC 1DTD (Exhaust Cycle 360)”).

[0243] Two samples of each cell were tested, and the cells were cycled at C / 3:C / 3 rates, with one full C / 20 cycle every 50 cycles.

[0244] Fig. 22B Shown with Fig.22A Discharge capacity versus cycle time and normalized discharge capacity versus cycle time for the same battery compositions were prepared and tested at 3.9 V and an operating temperature of 85° C. Two samples of each battery were tested, and the batteries were cycled at C / 3:C / 3 rates, with one full C / 20 cycle every 50 cycles.

[0245] The baseline electrolyte system equilibrated to 3.8 V was outgassed after 350 and 360 cycles, respectively, due to gas accumulation. Fig.22A As shown, Ni83 / PG cells containing a mixed blend ratio of 20% DMOHC and 80% DEC cycled at 3.8 V at an operating temperature of 85°C retain more than 97% of the initial capacity after about 400 cycle hours. It is worth noting that the electrolyte with a solvent blend of DMOHC and DEC has an advantage over EC:DEC in terms of gas generation, since the cell with DMOHC:DEC did not generate observable gas for 380 cycles.

[0246] In addition, due to gas accumulation, the baseline electrolyte system tested to 3.9 V was vented after 87 cycles or 100 cycles (“EC:DEC 1:1 2VC 1DTD (Vent Cycle 87)” and “EC:DEC 1:1 2VC 1DTD (Vent Cycle 100)”, respectively). Fig. 22B As shown, a Ni83 / PG battery containing a mixed blend ratio of 20% DMOHC and 80% DEC cycled at 3.9 V at an operating temperature of 85°C retains more than 95% of the initial capacity after more than 100 cycles. Fig.22A and 22B As shown, Ni83 / PG cells containing electrolytes with solvent blends of DMOHC and DEC performed as well or better than the baseline electrolyte system at C / 3 and 85°C when equilibrated to 3.8 V and 3.9 V and showed no gas accumulation.

[0247] Example 16 - Preparation method

[0248] A general synthesis for preparing compounds of formula (I) is outlined in Scheme 1, and Table 2 summarizes various compounds synthesized by the general procedure.

[0249] Solution 1

[0250]

[0251] Table 2. Summary of various DMOHC derivative compounds synthesized

[0252]

[0253]

[0254] The corresponding 1,2-diol (1 equivalent, 150mmol) and pyridine (2.5 equivalents, 375mmol) were added to a dry 1000mL round-bottom flask. The flask was then purged with argon. The 1,2-diol and pyridine were then dissolved in anhydrous dichloromethane (DCM, 200mL). The flask was cooled in an ice bath, and 5mL of methyl chloroformate (2.5 equivalents, 375mmol) was added dropwise over 3 hours. The reaction was then warmed to room temperature and left to stir overnight. The next day, the reaction was precipitated by adding diethyl ether (250mL), and then vacuum filtered to remove solid pyridine-HCl. The filtrate (clear off-white liquid) was then rotary evaporated to remove excess solvent to obtain a crude product as a viscous liquid. The crude product is then purified by rapid column chromatography, using silica gel as the stationary phase, eluted by cyclohexane:ethyl acetate in a ratio of 90:10 to 0:100 or dichloromethane:ethyl acetate in a ratio of 95:5 to 0:100. After removing the solvent under vacuum, the pure product is isolated as a transparent, colorless, viscous liquid in a yield of up to 70%. The product is then dried with calcium hydride in an argon-filled glove box to provide a water content of less than 20ppm. The product is then filtered through a 0.2 μm PTFE membrane to provide a final DMOHC derivative.

[0255] Although certain embodiments of the present invention have been described, these embodiments are given by way of example only and are not intended to limit the scope of the present disclosure. In fact, the novel methods and systems described herein may be embodied in a variety of other forms. In addition, various omissions, substitutions, and deformations may be made to the systems and methods described herein without departing from the spirit of the present disclosure. The accompanying claims and their equivalents are intended to cover forms or modifications that fall within the scope and spirit of the present disclosure. Therefore, the scope of the present invention is defined only by reference to the accompanying claims.

[0256] Features, materials, characteristics or groups described in conjunction with a particular aspect, embodiment or example should be understood to be applicable to any other aspect, embodiment or example described in this section or elsewhere in this specification unless incompatible therewith. All features disclosed in this specification (including any accompanying claims, abstracts and drawings) and / or all steps of any method or process disclosed may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The scope of protection is not limited to the details of any preceding embodiments. The scope of protection extends to any novel feature or any novel combination disclosed in this specification (including any accompanying claims, abstracts and drawings), or any novel step or any novel combination of any method or process disclosed.

[0257] In addition, certain features described in the present disclosure in the context of separate implementations may also be implemented in combination in a single implementation. Accordingly, certain features described in the context of a single implementation may also be implemented separately in multiple implementations or in any suitable sub-combination. In addition, although features may be described as functioning in certain combinations, in some cases, one or more features in a claimed combination may be deleted from the combination, and the combination may be claimed as a sub-combination or a variation of a sub-combination.

[0258] In addition, although the operations may be shown in the figure or described in the specification in a particular order, in order to achieve the desired results, these operations do not have to be performed in the particular order shown or in sequence, nor do they have to perform all operations. Other operations not shown or described may be incorporated into the exemplary methods and processes. For example, one or more additional operations may be performed before, after, at the same time, or between the operations. In addition, the operations may be rearranged or reordered in other implementations. It will be understood by those skilled in the art that in some embodiments, the actual steps taken in the process shown and / or disclosed may be different from the steps shown in the figure. Depending on the implementation, some of the above steps may be deleted, and other steps may be added. In addition, the features and attributes of the above-mentioned specific embodiments may be combined in different ways to form additional embodiments, all of which belong to the scope of the present disclosure. In addition, the separation of various system components in the above implementations should not be understood as requiring such separation in all implementations, and it should be understood that the components and systems described can generally be integrated together in a single product or packaged into multiple products. For example, any component of the energy storage system described herein may be provided separately or integrated together (e.g., packaged together or connected together) to form an energy storage system.

[0259] For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not all of these advantages must be achieved according to any particular embodiment, and thus, for example, those skilled in the art will recognize that the present disclosure may be embodied or performed in a manner that achieves one advantage or group of advantages taught herein without necessarily achieving other advantages taught herein or thereto.

[0260] Conditional language, such as "can / could / might / may", unless expressly stated otherwise or otherwise understood in the context of use, is generally intended to indicate that certain embodiments include certain features, elements, and / or steps while other embodiments do not. Thus, such conditional language generally does not imply that features, elements, and / or steps are in any way required for one or more embodiments, or that one or more embodiments must include logic that determines, with or without user input or prompting, whether such features, elements, and / or steps are included in any particular embodiment or are to be performed in any particular embodiment.

[0261] Unless expressly stated otherwise, linking language such as the phrase "at least one of X, Y, and Z" should be understood as generally used to convey, depending on the context, that an item, term, etc. may be X, Y, or Z. Thus, such linking language does not generally imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z.

[0262] Language of degree as used herein, such as the terms "approximately," "about," "generally," and "substantially" as used herein, refers to a value, amount, or characteristic that is close to a stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, depending on the desired function or desired result, the terms "approximately," "about," "generally," and "substantially" may refer to an amount within less than 10%, within less than 5%, within less than 1%, within less than 0.1%, and within less than 0.01% of a stated amount.

[0263] The scope of the present disclosure is not intended to be limited by the specific disclosure of preferred embodiments in this section or elsewhere in this specification, but rather may be defined by the claims in this section or elsewhere in this specification or in the future. The language of the claims should be interpreted broadly based on the language used in the claims and not limited to examples described in this specification or during the prosecution of the application, which examples should be interpreted as non-exclusive.

Claims

1. An energy storage device, comprising: cathode; anode; A separator disposed between the cathode and the anode; and An electrolyte comprising a solvent and an alkali metal salt, wherein the solvent comprises a compound represented by formula (I): in R1 and R2 are each independently an optionally substituted C 1-12 Alkyl; and R3 is optionally substituted C 1-12 Alkylene.

2. The energy storage device according to claim 1, wherein R1 and R2 are each independently selected from an optionally substituted methyl group, an optionally substituted ethyl group, an optionally substituted propyl group, an optionally substituted butyl group, an optionally substituted isopropyl group, an optionally substituted isobutyl group and an optionally substituted sec-butyl group.

3. The energy storage device according to claim 1 or 2, wherein the optional substitutions of R1 and R2 are each independently selected from at least one halogen.

4. The energy storage device according to any one of claims 1 to 3, wherein the optional substitution of R3 is selected from at least one C 1-12 Alkyl, C 1-12 Haloalkyl, halogen, and combinations thereof.

5. The energy storage device according to any one of claims 1 to 4, wherein R3 is an optionally substituted ethylene group or an optionally substituted propylene group.

6. The energy storage device according to any one of claims 1 to 5, wherein the compound is as shown in formula (Ia): Wherein R4, R5, R6 and R7 are each independently selected from -H, halogen, C 1-12 Alkyl and C 1-12 Halogenated alkyl.

7. The energy storage device of claim 6, wherein R4, R5, R6 and R7 are each independently selected from -H, CH3-, CH3CH2-, CH3CH2CH2-, CH3CH2CH2CH2-, (CH3)2CH-, CH3CH2CH(CH3)-, (CH3)3C-, -CF3, -CHF2, -CH2F, -CH2CF3, -CH2CHF2, -CH2CH2F, -CH2CH2Cl and -CH2CF2CF3.

8. The energy storage device according to claim 6 or 7, wherein R4 is selected from -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C- and -CF3.

9. The energy storage device according to any one of claims 6 to 8, wherein R5 is selected from -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C- and -CF3.

10. The energy storage device according to any one of claims 6 to 9, wherein R6 is selected from -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C- and -CF3.

11. The energy storage device according to any one of claims 6 to 10, wherein R7 is selected from -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C- and -CF3.

12. The energy storage device according to any one of claims 1 to 5, wherein the compound is as shown in formula (Ib): Among them, R8, R9, R 10 , R 11 , R 12 and R 13 are each independently selected from -H, halogen, C 1-12 Alkyl and C 1-12 Halogenated alkyl.

13. The energy storage device according to any one of claims 1 to 5, wherein the compound of formula (I) is selected from 14. The energy storage device according to any one of claims 1 to 13, wherein the alkali metal salt is a sodium salt.

15. The energy storage device according to any one of claims 1 to 13, wherein the alkali metal salt is a lithium salt.

16. The energy storage device of claim 15, wherein the lithium salt is LiFSI.

17. An energy storage device according to any one of claims 1 to 16, wherein the electrolyte further comprises a second solvent, the second solvent being selected from ethylene carbonate (EC), propylene carbonate (PC), vinyl ethylene carbonate (VEC), vinylene carbonate (VC), fluoroethylene carbonate (FEC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl acetate (MA), ethyl acetate (EA), propionitrile (PN), acetonitrile (AN), gamma-butyl lactone (GBL), and combinations thereof.

18. The energy storage device of claim 17, wherein the ratio between the solvent and the second solvent is about 1:4 to about 4:

1.

19. The energy storage device of any one of claims 1-18, wherein the energy storage device is configured to provide at least 96% initial capacity retention after 2,000 hours of cycling when operating between 3.0 V and 4.3 V.

20. The energy storage device of any one of claims 1-19, wherein the energy storage device is configured to provide greater than 99% initial capacity retention after 2,000 hours of cycling when operated between 3.0 V and 3.8 V at a temperature of at least 70°C.

21. A method for preparing an energy storage device, comprising: A cathode, an anode, a separator disposed between the cathode and the anode, and an electrolyte are arranged in the housing; The electrolyte comprises a solvent and an alkali metal salt, wherein the solvent comprises a compound represented by formula (I): in R1 and R2 are each independently an optionally substituted C 1-12 Alkyl; and R3 is optionally substituted C 1-12 Alkylene.

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