Carbonate compounds for electrolyte compositions for energy storage devices, and methods therefor

Abstract

An electrolyte solvent, co-solvent, and formulation for an energy storage device having improved performance are provided herein. The improved performance can be realized as improved cycle stability in addition to an exceptionally high temperature (e.g., at least about 70 °C or about 70 - 85 °C) Coulombic efficiency, capacity, or conductivity. Such electrolyte formulations can include compounds of formula (I), such as dimethyl 2,5-dioxohexanedioate (DMOHC) and diethyl 2,5-dioxohexanedioate (DEOHC).

Description

Technical Field

[0001] [Cross - Reference to Related Applications] Any application in which a foreign or domestic priority claim is identified in the application data sheet or PCT patent application filed together with this application is incorporated herein by reference under 37 CFR 1.57, and Rules 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 ENERGY STORAGE DEVICE ELECTROLYTE COMPOSITIONS, AND METHODS THEREOF", the disclosure of which is incorporated herein by reference in its entirety for all purposes.

[0002] The present disclosure generally relates to energy storage devices, and more particularly to improved electrolyte formulations for use in energy storage devices.

Background Art

[0003] Energy storage devices are widely used to power electronic devices, electromechanical devices, electrochemical devices, and other useful devices. Such batteries include primary chemical batteries, secondary (rechargeable) batteries, fuel cells, and various types of capacitors (including ultracapacitors). An increase in the operating voltage and temperature of energy storage devices, including batteries and capacitors, is considered desirable for enhanced energy storage, increased power capacity, and expanded real - world use cases.

[0004] Lithium-ion batteries have been relied upon as a power source in a number of commercial and industrial applications, for example, in consumer devices, productivity devices, and battery-powered vehicles. However, the demand placed on energy storage devices is growing continuously and rapidly. For example, the automotive industry is developing vehicles that rely on small and efficient energy storage, such as plug-in hybrid vehicles and battery electric vehicles. Lithium-ion batteries are well-suited to meet future demand, but there is a need to improve the energy density in order to provide a longer-life battery that can travel further on a single charge. The electrolyte is a component in conventional lithium-ion batteries that determines the electrochemical performance and battery safety, and the compatibility between the electrode and the electrolyte partially affects the battery performance.

Summary of the Invention

[0005] To summarize the advantages achieved over the present invention and the prior art, specific objects and advantages of the present invention are described herein. Not all of such objects or advantages can 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 implemented in a manner that achieves or optimizes one advantage or group of advantages taught herein without necessarily achieving other objects or advantages that may be taught or suggested herein.

[0006] In one aspect, an energy storage device is described. The energy storage device includes a cathode, an anode, a separator disposed between the cathode and the anode, and an electrolyte including a solvent and an alkali metal salt, the solvent including a compound of formula (I):

Chemical formula

[0007] In some embodiments, R1 and R2 are each independently selected from the group consisting of methyl and ethyl, and R3 is (-CH2CH2-). In some embodiments, R1 and R2 are each independently optionally substituted methyl, optionally substituted ethyl, optionally substituted propyl, optionally substituted butyl, optionally substituted isopropyl, optionally substituted isobutyl, and optionally substituted sec-butyl selected from the group consisting of. In some embodiments, the optional substituents R1 and R2 are each independently selected from at least one halogen. In some embodiments, the optional substituent R3 is at least one C1~ 12 alkyl, C1~ 12 haloalkyl, halogen, and combinations thereof selected from the group consisting of. In some embodiments, R3 is optionally substituted ethylene or optionally substituted propylene.

[0008] In some embodiments, the compound has the formula (Ia):

Chemical formula

[0009] In some embodiments, the compound has the formula (Ib):

Chemical formula

[0010] In some embodiments, the compound of formula (I)

Chemical formula

Chemical formula

[0011] 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 selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), vinylene carbonate (VEC), vinyl ethylene 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), butyrolactone (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 from about 1:4 to about 4:1.

[0012] In some embodiments, the energy storage device of the present disclosure has a retention rate of at least 96% of the initial capacity after 2000 cycles when operating between 3.0V and 4.3V. In other embodiments, the energy storage device of the present disclosure has a retention rate exceeding 99% of the initial capacity after 2000 cycles when operating between 3.0V and 3.8V at a temperature of at least 70°C.

[0013] In another aspect, a method of fabricating an energy storage device is described. The method includes disposing a cathode, an anode, a separator disposed between the cathode and the anode, and an electrolyte in a housing, the electrolyte including a solvent and an alkali metal salt, the solvent including a compound represented by formula (I): [Chemical formula] wherein: R1 and R2 are each independently C1 to optionally substituted 12is alkyl, and R3 is optionally substituted C1~ 12 is alkylene.

Brief Description of the Drawings

[0014]

Figure 1A

[0015]

Figure 1B

[0016]

Figure 2A

[0017]

Figure 2B

[0018]

Figure 3

[0019]

Figure 4

[0020]

Figure 5

[0021]

Figure 6A

[0022]

Figure 6B

[0023]

Figure 6C

[0024]

Figure 7

[0025]

Figure 8

[0026]

Figure 9

[0027]

Figure 10

[0028]

Figure 11

[0029]

Figure 12

[0030]

Figure 13A

[0031]

Figure 13B

[0032]

Figure 14

[0033]

Figure 15

[0034]

Figure 16

[0035]

Figure 17

[0036]

Figure 18

[0037]

Figure 19

[0038]

Figure 20A

[0039]

Figure 20B

[0040]

Figure 21A

[0041]

Figure 21B

[0042]

Figure 22A

[0043]

Figure 22B

[0044] Disclosed is an electrolyte formulation comprising a solvent that improves the lifespan and / or energy density of an energy storage device (e.g., a lithium-ion battery and / or a sodium-ion battery) at elevated voltages and / or temperatures. Such a solvent can interact with an alkali metal salt (e.g., a sodium salt and / or a lithium salt) to improve the performance of the device. Such a solvent can interact with a lithium salt to improve the performance of the device, such as improving cycle stability at high temperatures (e.g., at least about 70 - 85 °C). In some embodiments, the electrolyte for an energy storage device may comprise a solvent comprising a compound of formula (I) (e.g., formula (Ia) and / or formula (Ib)), as described later herein. In some embodiments, the electrolyte for an energy storage device may further comprise a LiFSI lithium salt. Additionally, the electrolyte for an energy storage device may also include dimethyl carbonate (DMC) as a co-solvent.

[0045] In some embodiments, the energy storage device disclosed herein has a retention rate of at least 99% of the initial capacity after 3000 charge-discharge cycles when operating at 3.0 V - 3.8 V, or has a retention rate of at least 96% when operating at 3.0 V - 4.3 V at a temperature of at least 70 °C. The capacity of conventional energy storage devices and batteries rapidly depletes under such voltages and high temperatures, but it has been discovered that the energy storage device disclosed herein has successfully increased the retention rate of the initial capacity compared to a comparative energy storage device without such an electrolyte formulation. Thus, the electrolyte formulation provided herein demonstrates improved cycle stability at high temperatures in addition to improved capacity retention against nominal capacity degradation over the entire lifespan of the device.

[0046] · Definitions When a group is described as "optionally substituted", it must necessarily be either unsubstituted or may be substituted with one or more of the indicated substituents. Similarly, when a group is described as "unsubstituted or substituted", if it is substituted, the substituent(s) can be selected from one or more of the indicated substituents. When no substituents are indicated, an indicated "optionally substituted" or "substituted" group is deuterium (D), halogen, hydroxy, C1-4 alkoxy, C1-8 alkyl, C3- 20 cycloalkyl, aryl, heteroaryl, heterocyclyl, C1-6 haloalkyl, cyano, C2-8 alkenyl, C2-8 alkynyl, C3- 20 cycloalkenyl, aryl(alkyl), heteroaryl(alkyl), heterocyclyl(alkyl), acyl, thiocarbonyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amide, N-amide, C-thioamide, N-thioamide, S-sulfonamide, N-sulfonamide, C-carboxy, O-carboxy, sulfenyl, sulfinyl, sulfonyl, haloalkoxy, amino, a mono-substituted amine group and a di-substituted amine group, meaning that it can be substituted with one or more groups individually and independently selected therefrom.

[0047] As used herein, "C a ~C b " in "a" and "b" are integers that refer to the number of carbon atoms in the group. The indicated group can contain from "a" to "b" (inclusive) carbon atoms. Thus, for example, a "C1-C4 alkyl" group refers to all alkyl groups having from 1 to 4 carbons, i.e., CH3-, CH3CH2-, CH3CH2CH2-, (CH3)2CH-, CH3CH2CH2CH2-, CH3CH2CH(CH3)-, and (CH3)3C-. When "a" and "b" are not specified, the broadest scope described in these definitions is assumed.

[0048] 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, t-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. The alkyl group may have 1 to 30 carbon atoms (whenever it appears herein, a numerical range such as "1 to 30" refers to each integer within the given range. For example, "1 to 30 carbon atoms" means that the alkyl group may consist of 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc., up to 30 carbon atoms, but this definition also encompasses the presence of the term "alkyl" for which no numerical range is specified). The alkyl group may also be a medium-chain alkyl having 1 to 12 carbon atoms. The alkyl group may also be a lower alkyl having 1 to 6 carbon atoms. The alkyl group may be substituted or unsubstituted.

[0049] As used herein, the term "alkenyl" refers to a monovalent straight-chain or branched-chain group of 2 to 30 carbon atoms containing a carbon-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.

[0050] As used herein, the term "alkynyl" refers to a monovalent straight-chain or branched-chain group of 2 to 30 carbon atoms containing a carbon-carbon triple bond(s), including, but not limited to, 1-propynyl, 1-butynyl, 2-butynyl, etc. The alkynyl group may be unsubstituted or substituted.

[0051] As used herein, the term "carbonyl" refers to C=O (i.e., a carbon double-bonded to oxygen).

[0052] The "alkylene" group refers to a straight-chain CH2 linking group that forms a bond connecting molecular fragments through terminal carbon atoms. Examples include, but are not limited to, methylene (-CH2-), ethylene (-CH2CH2-), propylene (-CH2CH2CH2-), and butylene (-CH2CH2CH2CH2-). The lower alkylene group can be substituted by replacing one or more hydrogens of the lower alkylene group with substituents listed under the definition of "substituted".

[0053] As used herein, the term "halogen atom" or "halogen" means any one of the radiation-stable atoms in Group 7 of the periodic table, such as fluorine, chlorine, bromine, and iodine.

[0054] 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 may be substituted or unsubstituted.

[0055] 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. Haloalkoxy may be substituted or unsubstituted.

[0056] As used herein, the term "alkali metal" means any one of the atoms in Group 1 of the periodic table, excluding hydrogen, such as lithium, sodium, potassium, rubidium, cesium, and francium.

[0057] As used herein, "salt" refers to any material that is formed when a leaving group or a hydrogen in acid form is replaced by a metal or its equivalent and that ionizes when dissolved in a solvent (e.g., water or a polar organic solvent) at an appropriate pKa.

[0058] · Solvent In some embodiments, the electrolyte includes a liquid solvent. The solvents provided herein need not dissolve all components and need not completely dissolve each component of the electrolyte. In further embodiments, the solvent can include an organic solvent. In some embodiments, the solvent can include one or more functional groups selected from carbonates, dimeric carbonates, ethers, and / or esters. In some embodiments, the electrolyte includes one solvent. In other embodiments, the electrolyte includes multiple solvents. In some embodiments, the solvent can include a decarbonated alkyl compound and / or a dimerized compound (e.g., a didecarbonated alkyl compound).

[0059] In some embodiments, the solvent has the formula (I):

Chemical formula

[0060] In some embodiments, R1 and R2 are each independently C1- 12 alkyl optionally substituted. In some embodiments, R1 is C1- 12 alkyl optionally substituted. In some embodiments, R2 is C1- 12It is alkyl. For example, in some embodiments, R1 and R2 are each independently selected from the group consisting of optionally substituted methyl, optionally substituted ethyl, optionally substituted propyl, optionally substituted butyl, optionally substituted isopropyl, optionally substituted isobutyl, and optionally substituted sec-butyl. In another example, in some embodiments, R1 and R2 are each independently selected from the group consisting of methyl and ethyl. In some embodiments, R1 and R2 are each independently selected from the group consisting of 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 ethyl.In certain embodiments, the optional substituents 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.

[0061] In some embodiments, R3 is optionally substituted C1~ 12 alkylene. For example, in some embodiments, R3 is optionally substituted ethylene or optionally substituted propylene. In some embodiments, R3 is optionally substituted ethylene. In some embodiments, R3 is optionally substituted propylene. In some embodiments, R3 is (-CH2CH2-). In other embodiments, R3 is (-CH2CH2CH2-). In some embodiments, the optional substituent R3 is at least one C1~ 12 alkyl, C1~ 12 haloalkyl, halogen, and combinations thereof.

[0062] In some embodiments, the compound is of formula (Ia):

Chemical formula

[0063] In some embodiments, R4, R5, R6 and R7 are each independently -H, halogen, C1~ 12 alkyl, and C1~ 12It is selected from the group consisting of haloalkyl. In other embodiments, R4, R5, R6, and R7 are each independently -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 the group consisting of -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C-, and -CF3.

[0064] In some embodiments, R4 is -H, halogen, C1~ 12 alkyl, and C1~ 12 It is selected from the group consisting of haloalkyl. In other embodiments, R4 is -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 the group consisting of -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C-, and -CF3.

[0065] In some embodiments, R5 is -H, halogen, C1~ 12 alkyl, and C1~ 12It is selected from the group consisting of haloalkyl. In other embodiments, R5 is selected from the group consisting of -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 the group consisting of -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C-, and -CF3.

[0066] In some embodiments, R6 is selected from the group consisting of -H, halogen, C1~ 12 alkyl, and C1~ 12 haloalkyl. In other embodiments, R6 is selected from the group consisting of -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 the group consisting of -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C-, and -CF3.

[0067] In some embodiments, R7 is selected from the group consisting of -H, halogen, C1~ 12 alkyl, and C1~ 12 haloalkyl. In other embodiments, R7 is selected from the group consisting of -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 the group consisting of -H, CH3-, CH3CH2-, CH3CH2CH(CH3)-, (CH3)3C-, and -CF3.

[0068] In some embodiments, the compound has the formula (Ib):

Chemical formula

[0069] In some embodiments, R8, R9, R 10 , R 11 , R 12 , and R 13 are each independently selected from the group consisting of -H, halogen, C1~ 12 alkyl, and C1~ 12 haloalkyl. In some embodiments, R8 is selected from the group consisting of -H, halogen, C1~ 12 alkyl, and C1~ 12 haloalkyl. In some embodiments, R9 is selected from the group consisting of -H, halogen, C1~ 12 alkyl, and C1~ 12 haloalkyl. In some embodiments, R 10 is selected from the group consisting of -H, halogen, C1~ 12 alkyl, and C1~ 12 haloalkyl. In some embodiments, R 11 is selected from the group consisting of -H, halogen, C1~ 12 alkyl, and C1~ 12 haloalkyl. In some embodiments, R 12 is selected from the group consisting of -H, halogen, C1~ 12 alkyl, and C1~ 12 haloalkyl. In some embodiments, R 13 is selected from the group consisting of -H, halogen, C1~ 12 alkyl, and C1~ 12 haloalkyl.

[0070] In some embodiments, the compound of formula (I) can be selected from at least one of the compounds shown in Table 1.

Table 1

[0071] In some embodiments, the solvent can include dimethyl 2,5-dioxohexanedioate (DMOHC). In some embodiments, the solvent can include diethyl 2,5-dioxohexanedioate (DEOHC). In some embodiments, the solvent can include ethylmethyl 2,5-dioxohexanedioate (EMOHC). In some embodiments, the compound of formula (I) is

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0072] In some embodiments, the solvent can include a carbonate. In further embodiments, the carbonate can 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 acyclic carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and combinations thereof. For example, in some embodiments, the solvent further includes DMC. In some embodiments, the solvent further includes DEC. In some embodiments, the solvent can further include methyl acetate (MA). In some embodiments, the solvent can include ethyl acetate (EA). In some embodiments, the solvent can include propionitrile (PN). In some embodiments, the solvent can include acetonitrile (AN). In some embodiments, the solvent can include butyrolactone (GBL).

[0073] Figure 1A shows the phase diagram of a mixture of dimethyl carbonate (DMC) and dimethyl-2,5-dioxohexanedioate (DMOHC) at various temperatures, and Figure 1B shows the phase diagram of a mixture of DMC and ethylene carbonate (EC) at various temperatures. As seen in Figures 1A and 1B, the phase diagram of the mixture of DMC and DMOHC is relatively similar to the phase diagram of the mixture of DMC and EC. Thus, the two solvent systems can be expected to be in the liquid phase at similar temperatures.

[0074] In some embodiments, the electrolyte comprises at least about 80 wt%, 81 wt%, 82 wt%, 83 wt%, 84 wt%, 85 wt%, 86 wt%, 87 wt%, 88 wt%, 89 wt%, 90 wt%, 91 wt%, 92 wt%, 93 wt%, 94 wt%, 95 wt%, 96 wt%, 97 wt%, or 98 wt%, or any range of values therebetween, of the total solvent, by weight, at least about that value, or at least about that value. In some embodiments, the electrolyte comprises at least about 80 wt%, 81 wt%, 82 wt%, 83 wt%, 84 wt%, 85 wt%, 86 wt%, 87 wt%, 88 wt%, 89 wt%, 90 wt%, 91 wt%, 92 wt%, 93 wt%, 94 wt%, 95 wt%, 96 wt%, 97 wt%, or 98 wt%, or any range of values therebetween, of each solvent, by weight, at least about that value, or at least about that value.

[0075] 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 range of values therebetween. In some embodiments, the electrolyte comprises a first solvent and a second solvent. In some embodiments, the electrolyte solvent system can comprise the first and second solvents 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 of values therebetween. For example, in some embodiments, the volume ratio can 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 the group consisting of 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), butyrolactone (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).

[0076] ·Electrolyte The electrolyte formulations described herein can include an alkali metal salt (e.g., a lithium salt and / or a sodium salt) and one or more solvents described herein. Generally, 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 can be selected from NaPF6, NaBF4, NaClO4, NaN(FSO2)2 (NaFSI), NaB(C2O4)2, and combinations thereof. In some embodiments, the lithium salt can be selected from lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium difluoro(oxalato)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 can 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 is 0.1M, 0.2M, 0.3M, 0.4M, 0.5M, 0.6M, 0.7M, 0.8M.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, 3.4 M, 3.5 M, 3.6 M, 3.7 M, 3.8 M, 3.9 M, 4 M, 4.1 M, 4.2 M, 4.3 M, 4.4 M, 4.5 M, 4.6 M, 4.7 M, 4.8 M, 4.9 M, 5 M, 5.1 M, 5.2 M, 5.3 M, 5.4 M, 5.5 M, 5.6 M, 5.7 M, 5.8 M, 5.9 M, 6 M, 6.1 M, 6.2 M, 6.3 M, 6.4 M, 6.5 M, 6.6 M, 6.7 M, 6.8 M, 6.9 M, or 7 M, or any value within a range between them, about that value, up to and including that value, or up to and including about that value. For example, in some embodiments, the salt concentration can be from about 0.1 M to about 5 M, from about 0.2 M to about 3 M, from about 0.3 M to about 2 M, or from about 0.7 M to about 1.5 M.

[0077] In some embodiments, the electrolyte further comprises one or more additional additives. In some embodiments, the additives can be selected from, for example, vinylene carbonate (VC), ethylene sulfate (DTD), lithium difluorophosphate (LFO), fluoroethylene carbonate (FEC), propene sulfone (PES), phenyl trifluoromethyl sulfide (PTS), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)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 tetrafluoroxalate phosphate (LiTFOP), lithium difluorodioxalate phosphate (LiDFDOP), and combinations thereof. In some embodiments, the electrolyte comprises each additive at 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 7 wt%, or 8 wt%, or any value in the range therebetween, about that value, up to and including that value, or up to and including about that value. In some embodiments, the electrolyte comprises a plurality of additives that total 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, 10 wt%, 11 wt%, or 12 wt%, or any value in the range therebetween, about that value, up to and including that value, or up to and including about that value.

[0078] Figures 2A and 2B show the viscosity vs. temperature for various electrolyte solutions and solvent combinations, including 1.0 M LiFSI in 80:20 DMOHC:DMC, 1.12 M LiFSI in DMOHC, 1.0 M LiPF6 in 3:7 EC:DMC, pure DMOHC, pure DEOHC, 3:7 EC:DMC, and 80:20 DMOHC:DMC. As seen in Figures 2A and 2B, the viscosities of pure DMOHC and DEOHC are higher than those of the 3:7 EC:DMC and 80:20 DMOHC:DMC solvent systems, and the addition of lithium salts generally further increases the viscosity of the electrolyte composition. Additionally, it was observed that LiPF6 dissolved in DMOHC within approximately 5 days at room temperature, and LiFSI dissolved in DMOHC at a higher rate (i.e., in less than 5 days) compared to the rate of LiPF6 at room temperature. Thus, Figures 2A and 2B demonstrate that cells containing DMOHC or DEOHC as the sole solvent may require operation at elevated temperatures (e.g., at least about 40 °C or about 40 - 85 °C) to reduce viscosity and thereby result in an increase in the ionic conductivity required for the electrolyte. Alternatively, Figures 2A and 2B demonstrate that DMOHC and DEOHC can be blended with one or more low-viscosity solvents, such as DMC or 30:70 EC:DMC, for example, to achieve the viscosity of the electrolyte that can be used in energy storage devices operating at room temperature.

[0079] 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, 30 cP, 31 cP, 32 cP, 33 cP, 34 cP, 35 cP, 36 cP, 37 cP, 38 cP, 39 cP, 40 cP, 40 cP, 41 cP, 42 cP, 43 cP, 44 cP, 45 cP, 46 cP, 47 cP, 48 cP, 49 cP, 50 cP, 51 cP, 52 cP, 53 cP, 54 cP, 55 cP, 56 cP, 57 cP, 58 cP, 59 cP, 60 cP, or any value in the range therebetween. For example, it may be from about 3 cP to about 8 cP, 8 cP to about 14 cP, 14 cP to about 20 cP, or 20 cP to about 55 cP.

[0080] · Energy storage device The energy storage device of the present disclosure includes the electrolyte, cathode, anode, and housing described herein, and the electrolyte, cathode, and anode are disposed within 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 anode each include an electrode film forming the electrode and the collected current.

[0081] In some embodiments, the electrode film provided herein includes at least one active material. In some embodiments, the electrode film further includes at least one binder.

[0082] In some embodiments, the electrode film contains an anode active material. In some embodiments, the anode active material can include, for example, an insertion material (such as carbon or graphite), an alloy / dealloying material (such as silicon, silicon oxide, tin, and / or tin oxide), a metal alloy or compound (such as Si-Al and / or Si-Sn), lithium titanate (LTO), and / or a conversion material (such as manganese oxide, molybdenum oxide, nickel oxide, and / or copper oxide). The anode active material can be used alone or mixed to form a multiphase material (such as 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, etc.). Examples of the anode active material include common natural graphite, synthetic or artificial graphite, surface-modified graphite, spherical graphite, flake graphite, and blends or combinations of these types of graphite for anodes, hard carbon, metal elements and their compounds, and metal-C composites.

[0083] In some embodiments, the electrode film contains a cathode active material. In some embodiments, the cathode active material can include, for example, a metal oxide, a metal sulfide, or an alkali metal oxide (such as a lithium metal oxide and / or a sodium metal oxide). The lithium metal oxide can 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 can be, for example, a layered transition metal oxide (LiCoO2 (LCO), Li(NiMnCo)O2 (NMC) and / or LiNi 0.8 Co 0.15 Al 0.05 O2 (NCA)), a spinel manganese oxide (LiMn2O4 (LMO) and / or LiMn 1.5 Ni 0.5 O4 (LMNO), etc.), an olivine (LiFePO4 (LFP), LiMn1-x Fe x It can include, for example, PO4 (such as LMFP). The cathode active material can include materials containing sulfur such as sulfur or lithium sulfide (Li2S), or other sulfur-based materials, or mixtures thereof. In some embodiments, the sodium metal oxide can be, for example, a layered oxide, a phosphate, and / or a ferricyanide (such as a compound of the Prussian white family). In some embodiments, the sodium metal oxide can be, for example, NaFe 0.5 Mn 0.5 O2, NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3 O2, NaFe2(CN)6, Na2VOPO4F, NaMnO2, and / or NaFe 0.3 Mn 0.5 Cu 0.2 O2.

[0084] The energy storage device provided herein can be of any suitable shape, for example, a planar shape, a helically twisted shape, a button shape, or a pouch 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 solar power generation system, or an energy recovery system for use in, for example, industrial machinery and / or transportation. The energy storage device provided herein can be used to supply power to various electronic devices and / or vehicles, including hybrid vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and / or electric vehicles (EVs).

[0085] In some embodiments, an energy storage device comprising an electrolyte formulation provided herein can demonstrate a higher discharge rate capability compared to a comparative energy storage device. Such a high discharge rate capability is desirable for high energy and high power applications such as electric vehicle propulsion. In some embodiments, an energy storage device comprising an electrolyte formulation provided herein can demonstrate improved cycle stability at exceptionally high temperatures (e.g., at least about 70 °C or about 70 - 85 °C).

[0086] An energy storage device containing the electrolyte formulation described herein may be characterized by an improved capacity retention over the entire duration of the device's service life. Further improvements that may be achieved in various embodiments include improvements in cycle performance, including improved storage stability during cycling and suppression of capacity degradation. In some embodiments, the improvement in cycle performance was achieved even at exceptionally 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 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 value in between, at about that value, at least at that value, or at least about that value. For example, 20 °C - 30 °C, 70 °C - 85 °C, 20 °C - 85 °C, or 50 °C - 85 °C. In some embodiments, the energy storage device is configured to operate at 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 value in between, or at about that value. For example, 2.5V - 4.5V, 3.0V - 4.2V, 4.1V - 4.3V, 2.5V - 3.7V, 3.3V - 3.4V, 3.0V - 4.3V, or 3V - 3.8V. In further embodiments, the lithium-ion battery is configured to have a minimum operating voltage of about 2.5V to about 3V, respectively. In still further embodiments, the lithium-ion battery is configured to have a maximum operating voltage of about 3.8V to about 4.4V, respectively.

[0087] In some embodiments, after 2000 hours of cycles at an operating temperature of at least 70°C, the energy storage device has a retention rate of the initial capacity of at least 99%, 98%, 97%, 96%, 95%, 94%, 93%, 92%, 91%, 90%, 89%, 88%, 87%, 86%, 85%, 84%, 83%, 82%, 81%, 80%, or any value in the range between them. For example, it is 99% - 90%, 99% - 95%, 98% - 91%, or 90% - 85%.

[0088] In some embodiments, the electrolyte formulations described herein may advantageously exhibit improved performance compared to typical electrolyte formulations. The performance may relate 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 the battery. Thus, a smaller ΔV value may indicate less polarization and lower impedance in the battery. As a result, an increase in ΔV with the number of cycles may indicate an increase in impedance during cycling. The first charge and discharge of the energy storage device (i.e., the "formation process") can be performed at the factory by the manufacturer. Thus, it may be advantageous to minimize gas generation during the formation process to simplify the manufacturing process. Charge transfer resistance is a measure of the difficulty encountered when electrons and lithium ions move into the anode or cathode material as lithium atoms during the operation of a lithium-ion battery. Thus, the greater the measured value of the charge transfer resistance, the more energy is lost during charge transfer.

[0089] In some embodiments, the energy storage device provided herein, after at least about 500 hours of cycles at an operating temperature of at least 70°C, when cycled between 2.5V and 4.5V, or between 2.5V and 4.3V, may have a discharge capacity retention rate 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 value within the range between them. In some embodiments, the energy storage device provided herein, after at least about 500 hours of cycles at an operating temperature of at least 70°C, when cycled at 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 value within the range between them, may have a discharge capacity retention rate of at least about 80%. In some embodiments, the energy storage device provided herein, at an operating temperature of at least 70°C, after at least 500 hours, 600 hours, 700 hours, 800 hours, 900 hours, 1000 hours, 1100 hours, 1200 hours, 1300 hours, 1400 hours, 1500 hours, 1600 hours, 1700 hours, 1800 hours, 1900 hours, 2000 hours, 2100 hours, 2200 hours, 2300 hours, 2400 hours, 2500 hours, 2600 hours, 2700 hours, 2800 hours, 2900 hours, 3000 hours, 3500 hours, 4000 hours, 4500 hours, 5000 hours, or any value within the range between them of time, when cycled between 2.5V and 4.5V, may have a discharge capacity retention rate of at least about 80%.In some embodiments, the energy storage device provided herein can have a discharge capacity retention rate of at least 80% when cycled between 2.5 V and 4.5 V after at least about 500 hours of cycles 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 any value in between.

[0090] The electrolyte formulations provided herein can be used with any of a number of energy storage devices and systems, such as one or more batteries, capacitor - battery hybrids, fuel cells, or other energy storage systems or devices, and combinations thereof, in various embodiments. In some embodiments, an electrolyte additive or an electrolyte containing the additives described herein can be implemented in a lithium - ion battery and / or a sodium - ion battery.

[0091] · Manufacturing method Some embodiments of the present disclosure relate to a method of manufacturing the energy storage device disclosed herein. In some embodiments, a method of manufacturing an energy storage device includes disposing a cathode, an anode, a separator disposed between the cathode and the anode, and an electrolyte within a housing. In some embodiments, the electrolyte includes a solvent and an alkali metal salt. The solvent includes a compound represented by formula (I) described herein.

Examples

[0092] Exemplary embodiments of the present disclosure, including processes, materials, and / or resulting products, are described in the following examples.

[0093] · Example 1 - Initial cycle matrix As shown in Figure 3, compared with the standard electrolyte system using 25:5:70 EC:EMC:DMC (i.e., "EED") as the solvent system, a battery using dimethyl 2,5-dioxohexanedioate (DMOHC) as the sole solvent, together with 2% vinylene carbonate (VC) as an additive, yielded excellent results. As the initial cycle matrix, the normalized discharge capacity of the NMC532 / artificial graphite battery with respect to the cycle time was tested. Figure 3 shows the following: (a) LiPF6 in 25:5:70 EC:EMC:DMC and 2% vinylene carbonate (VC) and 1% ethylene sulfate (DTD) (two examples of "EED LiPF6 c / 3 2VC+1DTD") (i.e., "control"), cycled with a 3-hour continuous charge-discharge protocol (C / 3) and performing a 20-hour charge-discharge cycle every 50 cycles, (b) LiPF6 and 2% VC in pure dimethyl 2,5-dioxohexanedioate (DMOHC) (LiPF6 C / 20), cycled with a 20-hour continuous charge-discharge protocol (C / 20), (c) LiPF6 and 2% VC in pure DMOHC (LiPF6 C / 10), cycled with a 10-hour continuous charge-discharge protocol (C / 10), (d) LiFSI in pure DMOHC, and 2% VC, C / 10 cycle (LiFSI C / 10), (e) LiFSI in pure DMOHC, and 2% VC, C / 20 cycle (LiFSI C / 20) shows the normalized discharge capacity versus cycle time of NMC532 / artificial graphite batteries with various lithium salts and additives, tested at an operating temperature of 70 °C and an operating voltage of 4.3 V, including the above.

[0094] As shown in Figure 3, the normalized discharge capacity versus cycle time of the battery with LiFSI in pure DMOHC resulted in exceptional capacity retention compared to the control electrolyte during C / 10 and C / 20. For example, the normalized capacity of a battery using DMOHC and LiFSI was about 90% after 6000 cycle hours, while the normalized capacity of a standard electrolyte system using 25:5:75 EC:EMC:DMC as the solvent reached the same capacity after about 2000 cycle hours.

[0095] ·Example 2 - LFP / PG battery with DMOHC and mixed blend As seen in Figure 4, a lithium iron phosphate (i.e., "LFP") battery that has LiFSI, 2% VC, and 1% DTD and utilizes pure graphite (i.e., "PG") as the anode operating at 70 °C exhibits the maximum C / 20 capacity retention rate. An LFP / PG battery with DMOHC and mixed blend was tested at 70 °C and C / 20 cycles. Figure 4 shows the following: (a) LiFSI in pure DMOHC, as well as 2% VC and 1% DTD, C / 20 cycles ("DMOHC_LiFSI_2VC_1DTD"), (b) LiPF6 in pure DMOHC, and 2% VC, C / 20 cycles ("DMOHC_LiPF6_2VC"), (c) LiFSI in pure DMOHC, and 2% fluoroethylene carbonate (FEC), C / 20 cycles ("DMOHC_LiFSI_2FEC"), (d) LiFSI in pure DMOHC, and 2% VC, C / 20 cycles ("DMOHC_LiFSI_2VC"), (e) LiFSI in 3:7 EC:DMC, and 2% VC, C / 3 cycles ("EC:DMC 3:7 LIFSI 2VC(C / 3)") (i.e., "Control 1"), (f) LiPF6 in 3:7 EC:DMC, and 2% VC, C / 3 cycles ("EC:DMC 3:7 LIPF6 2VC(C / 3)") (i.e., "Control 2") showing the normalized discharge capacity vs. cycle time and voltage polarization vs. cycle time of LFP / PG batteries with various lithium salts and additives, including the above.

[0096] Figure 5 shows the following: (a) 5 vol% DMOHC and LiFSI in 95 vol% of 3:7 EC:DMC, as well as 2% VC and 1% DTD, C / 20 cycles (「EC:DMC 3:7 LIFSI 2VC 1DTD 5DMOHC」), (b) 10 vol% DMOHC and LiFSI in 90 vol% of 3:7 EC:DMC, as well as 2% VC and 1% DTD, C / 20 cycles (「EC:DMC 3:7 LIFSI 2VC 1DTD 10DMOHC」), (c) 30 vol% DMOHC and LiFSI in 70 vol% of 3:7 EC:DMC, as well as 2% VC and 1% DTD, C / 20 cycles (「EC:OMC 3:7 LIFSI 2VC 1DTD 30DMOHC」), (d) 60 vol% DMOHC and LiFSI in 40 vol% of 3:7 EC:DMC, as well as 2% VC and 1% DTD, C / 20 cycles (「EC:DMC 3:7 LIFSI 2VC 1DTD 60DMOHC」), (e) LiPF6 in 3:7 EC:DMC, and 2% VC, C / 3 cycles (「EC:DMC 3:7 LIPF6 2VC(C / 3)」) (i.e., 「Control 2」), (f) LiFSI in 3:7 EC:DMC, and 2% VC, C / 3 cycles (「EC:DMC 3:7 LIFSI 2VC(C / 3)」) (i.e., 「Control 1」) The normalized discharge capacity vs. cycle time and voltage polarization vs. cycle time of LFP / PG batteries using electrolyte systems with various amounts of DMOHC, including the above, are shown.

[0097] As seen in Figure 4, batteries with electrolytes containing pure DMOHC and further containing additive VC or 2% VC + 1% DTD provided relatively the best capacity retention. In addition, batteries with electrolytes containing a 60:40 blend of DMOHC and EC:DMC provided relatively the best capacity retention, as demonstrated in Figure 5. Control electrolytes 1 and 2 using only the co-solvent EC:DMC 3:7 provided inferior capacity retention.

[0098] ·Post - formation weighing of a battery containing DMOHC and DEOHC As seen in FIGS. 6A - 6C, blending DMOHC with DMC in a lithium iron phosphate battery reduces impedance (R ct and ΔV) and reduces gas generation after a formation process carried out at 40 °C and C / 20. FIGS. 6A - 6C are as follows: (a) 1 M LiFSI and 2% VC + 1% DTD in pure DMOHC (「DMOHC, 1M LIFSI」), (b) 1 M LIPF6 and 2% VC + 1% DTD in pure DMOHC (「DMOHC, 1M LiPF6」), (c) 1 M LiFSI and 2% VC + 1% DTD in pure diethyl 2,5 - dioxohexanedioate (DEOHC) (「DEOHC, 1M LiFSI」), (d) 1 M LiFSI and 2% VC + 1% DTD in 40:60 DMOHC:DMC (「DMOHC:DMC 40:60, 1M LiFSI」), (e) 1 M LiFSI and 2% VC + 1% DTD in 20:80 DMOHC:DMC (「DMOHC:DMC 20:80, 1M LiFSI」), (f) 1 M LiFSI and 2% VC + 1% DTD in 30:70 EC:DMC (「EC:DMC 30:70, 1M LiFSI」) showing impedance and gas generation data for electrolyte formulations including.

[0099] As can be seen in FIGS. 6A and 6B, the charge transfer resistance of the lithium iron phosphate battery with 60% DMC resulted in improved results and reduced impedance compared to the batteries with pure DMOHC or pure DEOHC. Similarly, the lithium iron phosphate battery with LiFSI in 60% DMC and 40% DMOHC formed less gas than the lithium iron phosphate battery with LiFSI in pure DMOHC. FIG. 6C shows that the battery with LIPF6 in pure DMOHC resulted in improved results regarding gas generation when compared to the battery with LiFSI in pure DMOHC. In addition, the batteries with at least 60% DMC resulted in improved gas generation results when compared to the batteries with pure DMOHC or pure DEOHC.

[0100] ·Example 4 - Microcalorimetry and Parasitic Heat Flow of LFP Batteries FIG. 7 shows the average parasitic heat flow versus cycle number of an LFP / PG battery using the same electrolyte formulations as in FIGS. 6A - 6C. As can be seen in FIG. 7, the lowest parasitic heat flow in the microcalorimetry experiment corresponded to the best cycle life of the pure DMOHC battery seen in FIG. 4. The solvent blend resulted in improved parasitic heat flow results compared to the control electrolyte containing 30:70 EC:DMC. Thus, blending 20% - 40% DMOHC with DMC provided the best compromise between formation performance and cycle performance.

[0101] ·Example 5 - Normalized Discharge Capacity in LFP Batteries with DMOHC and Blend FIG. 8 is as follows: (a) 1M LiFSI in pure DMOHC, and 2% VC and 1% DTD (「DMOHC, 1M LiFSI, 2VC 1DTD」), (b) 1M LiFSI in 40:60 DMOHC:DMC, and 2% VC and 1% DTD (「DMOHC:DMC 40:60, 1M LiFSI, 2VC 1DTD」), (c) 1 M LiFSI in 20:80 DMOHC:DMC, as well as 2% VC and 1% DTD (「DMOHC:DMC 20:80, 1 M LiFSI, 2VC 1DTD」), (d) 1 M LiPF6 in pure DMOHC, as well as 2% VC and 1% DTD (「DMOHC, 1 M LiPF6, 2VC 1DTD」), (e) 1 M LiFSI in pure DEOHC, as well as 2% VC and 1% DTD (「DEOHC, 1 M LIFSI, 2VC 1DTD」), (f) 1.5 M LiPF6 in 30:70 EC:DMC, and 2% VC (「EC:DMC 30:70, 1.5 M LiPF6, 2VC」) (i.e., 「control」) shows the normalized discharge capacity versus cycle time of LFP / PG batteries tested at an operating temperature of 70 °C.

[0102] As seen in Figure 8, the batteries containing DMOHC and 20% or 40% DMC resulted in improved capacity retention compared to the control. Batteries containing pure DMOHC or DEOHC also resulted in improved capacity results compared to the control. For example, the normalized discharge capacity of the lithium iron phosphate battery using pure DMOHC after 3750 cycle times exceeded 92%, while the normalized capacity of the control electrolyte system was approximately 86% after 3750 cycle times. Therefore, all batteries with DMOHC and DEOHC resulted in improved capacity retention compared to the control electrolyte system.

[0103] · Example 6 - Capacity Retention in LFP / PG Batteries with DMOHC and Mixed Blends As seen in Figure 9, blending DMOHC with DMC results in improved capacity retention compared to the control electrolyte. Figure 9 shows the following: (a) LiFSI in 80:20 DMOHC:DMC, as well as 2% VC and 1% DTD, C / 20 cycle (「LFP DMOHC 80 DMC 20 LIFSI 2VC 1DTD」), (b) LiFSI in 60:40 DMOHC:DMC, along with 2% VC and 1% DTD, C / 20 cycles (「LFP DMOHC 60 DMC 40 LIFSI 2VC 1DTD」), (c) LiFSI in 40:60 DMOHC:DMC, along with 2% VC and 1% DTD, C / 20 cycles (「LFP DMOHC 40 DMC 60 LIFSI 2VC 1DTD」), (d) LiFSI in 20:80 DMOHC:DMC, along with 2% VC and 1% DTD, C / 20 cycles (「LFP DMOHC 20 DMC 80 LIFSI 2VC 1DTD」), (e) LiFSI in pure DMOHC, along with 2% VC and 1% DTD, C / 20 cycles (「LFP DMOHC LiFSI 2VC 1DTD (data cut-off)」), (f) LiFSI in 3:7 EC:DMC, and 2% VC, C / 3 cycles (「LFP EC:DMC 3:7 LIFSI 2VC C / 3 cycles (data cut-off)」) (i.e., 「control」) shows the normalized discharge capacity versus cycle time of LFP / PG batteries tested at an operating temperature of 70 °C.

[0104] Figure 9 demonstrates the performance advantages of batteries having electrolyte systems containing DMOHC and at least 20% DMC compared to a control electrolyte system. Batteries containing 40% DMOHC and 60% DMC provided the best cycle performance among the mixed DMOHC / DMC electrolyte systems. Batteries containing 100% DMOHC provided the best cycle results compared to the mixed DMOHC / DMC electrolyte systems and the control.

[0105] · Cycle matrix using Example 6 - DEOHC Figure 10 shows the following: (a) LiFSI in DEOHC, and 2% VC, C / 20 cycles between 3.0 V and 4.3 V (「DEOHC_LiFSI_2VC C / 20」), (b) Normalized discharge capacity vs. cycle time of NMC532 / artificial graphite (i.e., "AML") batteries tested between 3.0 V and 4.3 V at an operating temperature of 70 °C, including LiFSI in DEOHC, as well as 2% VC and 1% DTD, C / 20 cycles ( "DEOHC_LiFSI_2VC_1DTD C / 20"), (c) Normalized discharge capacity vs. cycle time of NMC532 / artificial graphite (i.e., "AML") batteries tested between 3.0 V and 4.3 V at an operating temperature of 70 °C, including LiFSI in DMOHC, and 2% VC, C / 20 cycles ( "LIFSI DMOHC C / 20") is shown.

[0106] Figure 11 shows the following: (a) Normalized discharge capacity vs. cycle time of LFP / PG batteries tested between 2.5 V and 3.65 V at an operating temperature of 70 °C, including LiFSI in DEOHC, and 2% VC, C / 20 cycles ( "DEOHC_LiFS1_2VC C / 20"), (b) Normalized discharge capacity vs. cycle time of LFP / PG batteries tested between 2.5 V and 3.65 V at an operating temperature of 70 °C, including LiFSI in DEOHC, as well as 2% VC and 1% DTD, C / 20 cycles ( "DEOHC_LiFSI_2VC_1DTD C / 20"), (c) Normalized discharge capacity vs. cycle time of LFP / PG batteries tested between 2.5 V and 3.65 V at an operating temperature of 70 °C, including LiFSI in DMOHC, as well as 2% VC and 1% DTD, C / 20 cycles ( "DMOHC_LiFSI_2VC_1DTD C / 20"), (d) Normalized discharge capacity vs. cycle time of LFP / PG batteries tested between 2.5 V and 3.65 V at an operating temperature of 70 °C, including LiFSI in 3:7 EC:DMC, and 2% VC, C / 3 cycles ( "EC:DMC_3:7_15M LiFSI LFP C / 3") (i.e., "control") is shown.

[0107] As seen in Figure 10, NMC532 / artificial graphite batteries with DMOHC and DEOHC show similar capacity retention performance. For batteries using LFP / PG, as demonstrated in Figure 11, batteries with DMOHC functioned better than batteries using DEOHC and the control. LFP / PG batteries with DEOHC showed improved results compared to the control battery.

[0108] · Capacity retention rate in the LFP / PG battery operated using 8-DEOHC and DMC Figure 12 is as follows: (a) LiFSI in 80:20 DEOHC:DMC, and 2% VC and 1% DTD, C / 20 cycles (「LFP / pure graphite DEOHC 80 DMC 20 LiFSI 2VC 1DTD C / 20」), (b) LiFSI in 60:40 DEOHC:DMC, and 2% VC and 1% DTD, C / 20 cycles (「LFP / pure graphite DEOHC 60 DMC 40 LiFSI 2VC 1DTD C / 20」), (c) LiFSI in 40:60 DEOHC:DMC, and 2% VC and 1% DTD, C / 20 cycles (「LFP / pure graphite DEOHC 40 DMC 60 LiFSI 2VC 1DTD C / 20」), (d) LiFSI in 20:80 DEOHC:DMC, and 2% VC and 1% DTD, C / 20 cycles (「LFP / pure graphite DEOHC 20 DMC 80 LiFSI 2VC 1DTD C / 20」), (e) LiFSI in pure DMOHC, and 2% VC and 1% DTD, C / 20 cycles (「LFP / pure graphite DMOHC LiFSI 2VC 1DTD (data cut-off) C / 20」), (f) LiFSI in 3:7 EC:DMC, and 2% VC, C / 3 cycles (「LFP / pure graphite EC:DMC 3:7 LIFSI 2VC C / 3 cycles (data cut-off)」) (i.e., 「control」) (g) LiFSI in pure DEOHC, and 2% VC and 1% DTD, C / 20 cycles (「LFP / pure graphite DEOHC LiFSI 2VC 1DTD C / 20」) shows the normalized discharge capacity vs. cycle time of the LFP battery tested at an operating temperature of 70 °C, including:

[0109] As shown in Figure 12, the normalized discharge capacity of the lithium iron phosphate battery with the DEOHC:DMC mixture after 2000 cycle times at 70 °C exceeded 93%. Similar results were observed for the lithium iron phosphate battery using pure DMOHC after 2000 cycle times. In contrast, the normalized capacity of the control electrolyte system using EC:DMC 3:7 was only about 91% after 2000 cycle times at 70 °C.

[0110] · Example 9 - NMC532 / graphite battery with DMOHC equilibrated at 3.8 V As shown in Figures 13A and 13B, the batteries with the electrolyte system containing DMOHC, LiFSI, 2% VC, and 1% DTD showed surprising capacity retention when tested at 70 °C. Figure 13A shows the following: (a) LiFSI in pure DMOHC, and 2% VC (「DMOHC_LiFSI_2VC」), (b) LiFSI in pure DMOHC, and 2% VC and 1% DTD (「DMOHC_LiFSI_2VC_1DTD」), (c) LiPF6 in pure DMOHC, and 2% VC and 1% DTD (「DMOHC_LiPF6_2VC_1DTD」) showing the normalized discharge capacity vs. cycle time of the NMC532 / graphite (i.e., 「AML」) battery equilibrated at 3.8 V, and Figure 13B shows the voltage polarization vs. cycle time of the battery.

[0111] Figure 14 shows the charge - discharge capacity vs. cycle time of the NMC532 / graphite battery tested at an operating temperature of 70 °C containing LiFSI, 2% VC, and 1% DTD in pure DMOHC (「DMOHC LIFSI 2VC 1DTD (charge)」 and 「DMOHC LIFSI 2VC 1DTD (discharge)」 respectively).

[0112] As can be seen in Figure 13A, the normalized capacity of the NMC532 / graphite battery with DMOHC and LiFSI after about 3500 cycle times was about 99%. Further, as can be seen in Figure 13B, an increase in the minimum voltage polarization with test time was observed in the NMC532 / graphite battery containing LiFSI and 2% VC in pure DMOHC and in the NMC532 / graphite battery having LiFSI as well as 2% VC and 1% DTD in pure DMOHC. Further, the minimum difference between the charge capacity and the discharge capacity was also observed in the NMC532 / graphite battery having LiFSI as well as 2% VC and 1% DTD in pure DMOHC, as shown in Figure 14. This represents a Coulombic efficiency of about 99.8% in charge-discharge cycles that take 40 hours at a temperature of 70 °C.

[0113] · Example 10 - NMC532 / graphite battery with DMOHC balanced at 3.8 V As can be seen in Figure 15, promising results were obtained by mixing DMOHC with DMC in the NMC532 / graphite (i.e., "AML") battery. Figure 15 shows the following: (a) LiFSI, 2% VC and 1% DTD in 80:20 DMOHC:DMC, C / 20 cycles ("LiFSI 80 DMOHC 20 DMC 2VC 1DTD C / 20"), (b) LiFSI, 2% VC and 1% DTD in 60:40 DMOHC:DMC, C / 20 cycles ("LiFSI 60 DMOHC 40 DMC 2VC 1DTD C / 20"), (c) LiFSI, 2% VC and 1% DTD in 40:60 DMOHC:DMC, C / 20 cycles ("LiFSI 40 DMOHC 60 DMC 2VC 1DTD C / 20"), (d) LiFSI, 2% VC and 1% DTD in 20:80 DMOHC:DMC, C / 20 cycles ("LiFSI 20 DMOHC 80 DMC 2VC 1DTD C / 20"), (e) In pure DMOHC, LiFSI, as well as 2% VC and 1% DTD, C / 20 cycles (「LiFSI DMOHC 2VC 1DTD C / 20」) shows the normalized discharge capacity versus cycle time of an NMC532 / artificial graphite battery equilibrated at 3.8 V, tested at an operating temperature of 70 °C.

[0114] As seen in Figure 15, solvent blend ratios such as 40% DMOHC and 60% DMC, 60% DMOHC and 40% DMC, or 80% DMOHC and 20% DMC all resulted in similar results with a normalized capacity exceeding 99% after approximately 2000 cycle times. The best cycle life results were observed in the battery with pure DMOHC.

[0115] · Example 11 - Cycle matrix at 85 °C Figure 16 shows the following: (a) LiFSI in 3:7 EC:DMC, as well as 2% VC and 1% DTD, C / 3 cycles at 3.65 V (「LFP / PG EC:DMC 3:7 LIFSI 2VC 1DTD 3.65V C / 3」) (i.e., 「Control 1」), (b) Two examples of LiFSI in pure DMOHC, as well as 2% VC and 1% DTD, C / 20 cycles at 3.65 V (「LFP / PG DMOHC LIFSI 2VC 1DTD 3.65V C / 20」) shows the normalized discharge capacity versus cycle time and voltage polarization versus cycle time of a lithium iron phosphate (i.e., 「LFP」) battery at an operating temperature of 85 °C.

[0116] Figure 17 shows the following: (a) Two examples of LiFSI in 3:7 EC:DMC, as well as 2% VC and 1% DTD, C / 3 cycles at 3.8 V (「NMC532 / SAF EC:DMC 3:7 LIFSI 2VC 1DTD 3.8V C / 3」) (i.e., 「Control 2」), (b) Normalized discharge capacity vs. cycle time and voltage polarization vs. cycle time of NMC532 / artificial graphite (i.e., "AML") cells at an operating temperature of 85 °C, including LiFSI in pure DMOHC, as well as 2% VC and 1% DTD, C / 20 cycles at 3.8 V (two examples of "NMC532 / SAF DMOHC LIFSI 2VC 1DTD 3.8V C / 20"), (c) Normalized discharge capacity vs. cycle time and voltage polarization vs. cycle time of NMC532 / artificial graphite (i.e., "AML") cells at an operating temperature of 85 °C, including LiFSI in a 1:1 DMOHC:DMC, as well as 2% VC and 1% DTD, C / 20 cycles at 3.8 V (two examples of "NMC532 / SAF DMOHC:DMC 1:1 LIFSI 2VC 1DTD 3.8V C / 20") are shown.

[0117] Figure 18 is as follows: (a) Normalized discharge capacity vs. cycle time and voltage polarization vs. cycle time of Ni83 / PG cells at an operating temperature of 85 °C, including LiFSI in a 3:7 EC:DMC, as well as 2% VC and 1% DTD, C / 3 cycles at 3.9 V (two examples of "Ni83 / PG EC:DMC 3:7 LIFSI 2VC 1DTD 3.9V C / 3") (i.e., "Control 3"), (b) Normalized discharge capacity vs. cycle time and voltage polarization vs. cycle time of Ni83 / PG cells at an operating temperature of 85 °C, including LiFSI in pure DMOHC, as well as 2% VC and 1% DTD, C / 20 cycles at 3.9 V (two examples of "Ni83 / PG DMOHC LIFSI 2VC 1DTD 3.9V C / 20"), (c) Normalized discharge capacity vs. cycle time and voltage polarization vs. cycle time of Ni83 / PG cells at an operating temperature of 85 °C, including LiFSI in a 1:1 DMOHC:DMC, as well as 2% VC and 1% DTD, C / 20 cycles at 3.9 V (two examples of "Ni83 / PG DMOHC:DMC 1:1 LIFSI 2VC 1DTD 3.9V C / 20") are shown. Ni83 / PG (where Ni83 is LiNi 0.83 Mn 0.11 Co 0.06 O2 available from Xiamen Tungsten Company (XTC, China))

[0118] The LFP / PG battery using DMOHC as the sole solvent showed improved results compared to the LFP / PG battery using 3:7 EC:DMC as the solvent system. The NMC532 / artificial graphite battery using DMOHC as the sole solvent functioned equivalently to the battery with 1:1 DMOHC:DMC during 20-hour charge-discharge cycles at 85 °C. For example, the normalized capacity of the NMC532 / artificial graphite battery equilibrated at 3.8 V at 85 °C using DMOHC or 1:1 DMOHC:DMC was about 99% after 700 cycle hours, while the normalized capacity of the standard electrolyte system using 3:7 EC:DMC as the solvent reached the same capacity after about 400 cycle hours. Similar results were observed in the Ni83 / PG battery. The normalized capacity of the Ni83 / PG battery at 85 °C using DMOHC or 1:1 DMOHC:DMC was about 98% after 700 cycle hours. In contrast, the normalized capacity of the Ni83 / PG battery at 85 °C using 3:7 EC:DMC as the solvent reached the same capacity after about 300 cycle hours. Some of the batteries have been tested for up to 1400 hours and continue to show similarly excellent results.

[0119] ·Example 12 - Ni83 / PG battery with DEC as co-solvent Figure 19 is as follows: (a) 1 M LiFSI in 20:80 DMOHC:DEC, and 2% VC and 1% DTD, 3.8 V (「20 DMOHC 80 DEC 2VC 1DTD 3.8V」), (b) 1 M LiFSI in 20:80 DMOHC:DEC, and 2% VC and 1% DTD, 3.9 V (「20 DMOHC 80 DEC 2VC 1DTD 3.9V」), (c) 1 M LiFSI in 20:80 DMe-DMOHC:DEC, and 2% VC and 1% DTD, 3.9 V (「20 DMe 80 DEC 2VC 1DTD 3.9V」), (d) 1 M LiFSI in 20:80 DMe-DMOHC:DEC, and 2% VC and 1% DTD, 3.8 V (「20 DMe 80 DEC 2VC 1DTD 3.8V」), (e) 1 M LiFSI in 20:80 Me-DMOHC:DEC, along with 2% VC and 1% DTD, 3.9 V (「20 MeDMOHC 80 DEC 2VC 1DTD 3.9V」 and 「20 MeDMOHC 80 DEC 2VC 1DTD 3.9V」) shows the discharge capacity vs. cycle time and normalized discharge capacity vs. cycle time of the Ni83 / PG battery at a C / 3 cycle (with C / 20:C / 20 cycles performed every 50 cycles) and an operating temperature of 85 °C.

[0120] As seen in Figure 19, a blend ratio of 20% Me-DMOHC and 80% DEC cycled at 3.9 V resulted in similar outcomes to 20% DMOHC and 80% DEC cycled at 3.8 V and 3.9 V. Additionally, Figure 19 demonstrates that DMOHC, Me-DMOHC, and DMe-DMOHC can be blended with diethyl carbonate (DEC) and used in lithium-ion batteries operating at 85 °C.

[0121] · Ni83 / PG battery with DMOHC and DEC tested up to 3.9 V in Example 13 Figure 20A shows the following: (a) 1 M LiFSI in 20:80 DMOHC:DEC, along with 2% VC and 1% DTD, cycled at 3.9 V for 388 cycles (two examples of 「DMOHC:DEC 2:8 2VC 1DTD (388 cycles)」) shows the discharge capacity vs. cycle time and normalized discharge capacity vs. cycle time of the Ni83 / PG battery at an operating temperature of 20 °C.

[0122] The battery was cycled at C / 3, where every 50 cycles, C / 20 charging was continuously used, followed by C / 20, C / 10, C / 5, C / 2, and C discharges.

[0123] Figure 20B shows the following: (a) 1 M LiFSI in 20:80 DMOHC:DEC, along with 2% VC and 1% DTD, 380 cycles at 3.9 V (「DMOHC:DEC 2:8 2VC 1DTD (380 cycles)」), (b) 1 M LiFSI in 20:80 DMOHC:DEC, along with 2% VC and 1% DTD, 385 cycles at 3.9 V (「DMOHC:DEC 2:8 2VC 1DTD (385 cycles)」) show the discharge capacity vs. cycle time and normalized discharge capacity vs. cycle time of the Ni83 / PG battery at an operating temperature of 85 °C.

[0124] The battery was cycled at C / 3. Every 50 cycles, a single C / 20:C / 20 cycle was performed.

[0125] As seen in Figure 20A, the Ni83 / PG battery with a blend ratio of 20% DMOHC and 80% DEC, cycled at 3.9 V at an operating temperature of 20 °C, retained more than 99% of its initial capacity after approximately 2500 cycle hours. As demonstrated in Figure 20B, the Ni83 / PG battery with a blend ratio of 20% DMOHC and 80% DEC, cycled at 3.9 V at an operating temperature of 85 °C, retained more than 90% of its initial capacity after approximately 2500 cycle hours. As seen in Figures 20A and 20B, the electrolyte with a solvent blend of DMOHC and DEC operates favorably at C / 3 at both 20 °C and 85 °C using a positive electrode rich in nickel such as Ni83.

[0126] · NMC640 / PG battery with DMOHC and DEC tested up to 3.9 V in Example 14 Figure 21A shows the following: (a) 1 M LiFSI in 20:80 DMOHC:DEC, along with 2% VC and 1% DTD, 273 cycles at 3.9 V (「DMOHC:DEC 2:8 2VC 1DTD (273 cycles)」), (b) 1 M LiFSI in 20:80 DMOHC:DEC, along with 2% VC and 1% DTD, 273 cycles at 3.9 V (「DMOHC:DEC 2:8 2VC 1DTD (338 cycles)」) shows the discharge capacity vs. cycle time and normalized discharge capacity vs. cycle time of the NMC640 battery containing it.

[0127] The battery was cycled at C / 3 at an operating temperature of 20 °C, where every 50 cycles, continuous C / 20 charging was used, followed by C / 20, C / 10, C / 5, C / 2, and C discharges.

[0128] Figure 21B shows the following: (a) Two examples of 1 M LiFSI in 20:80 DMOHC:DEC, along with 2% VC and 1% DTD, 365 cycles at 3.9 V (「DMOHC:DEC 2:8 2VC 1DTD (365 cycles)」) shows the discharge capacity vs. cycle time and normalized discharge capacity vs. cycle time of the NMC640 / PG battery containing it.

[0129] The battery was cycled at C / 3 at an operating temperature of 85 °C, where every 50 cycles, a single C / 20:C / 20 cycle was performed. As seen in Figure 21A, the NMC640 / PG battery containing a 20% DMOHC and 80% DEC blend ratio cycled at 3.9 V at an operating temperature of 20 °C retained more than 99% of its initial capacity after approximately 2500 cycle hours. As demonstrated in Figure 21B, the NMC640 / PG battery containing a 20% DMOHC and 80% DEC blend ratio cycled at 3.9 V at an operating temperature of 85 °C retained more than 90% of its initial capacity after approximately 2500 cycle hours. As seen in Figures 21A and 21B, electrolytes with a solvent blend of DMOHC and DEC operate favorably at C / 3 at both 20 °C and 85 °C using a cobalt-free cathode such as NMC640.

[0130] ·Example 15 - Ni83 / PG battery with DMOHC and DEC tested up to 3.8V and 3.9V Figure 22A shows the following: (a) 1M LiFSI in 20:80 DMOHC:DEC, and 2% VC and 1% DTD (two examples of "DMOHC:DEC 2:8 2VC 1DTD"), (b) 1M LiFSI in 1:1 EC:DEC, and 2% VC and 1% DTD ("EC:DEC 1:1 2VC 1DTD (vent cycle 350)" and "EC:DEC 1:1 2VC 1DTD (vent cycle 360)") showing the discharge capacity vs. cycle time and normalized discharge capacity vs. cycle time of Ni83 / PG batteries tested up to 3.8V at an operating temperature of 85°C.

[0131] Two samples of each battery were tested, the batteries were cycled at a rate of C / 3:C / 3, and full C / 20 cycles were performed every 50 cycles.

[0132] Figure 22B shows the discharge capacity vs. cycle time and normalized discharge capacity vs. cycle time of the same battery configuration fabricated for Figure 22A and tested up to 3.9V at an operating temperature of 85°C. Two samples of each battery were tested, the batteries were cycled at a rate of C / 3:C / 3, and full C / 20 cycles were performed every 50 cycles.

[0133] Due to gas accumulation, the baseline electrolyte systems equilibrated at 3.8V were vented after 350 cycles and 360 cycles respectively. As seen in Figure 22A, the Ni83 / PG battery containing a 20% DMOHC and 80% DEC blend ratio cycled at 3.8V at an operating temperature of 85°C retained more than 97% of its initial capacity after about 400 cycles. In particular, the battery with DMOHC:DEC did not produce observable gas over 380 cycles, so the electrolyte with the solvent blend of DMOHC and DEC offers an advantage over EC:DEC with respect to gas generation.

[0134] In addition, due to gas accumulation, the baseline electrolyte system tested up to 3.9 V was vented after 87 cycles or 100 cycles (respectively, "EC:DEC 1:1 2VC 1DTD (vent cycle 87)" and "EC:DEC 1:1 2VC 1DTD (vent cycle 100)"). As demonstrated in Figure 22B, the Ni83 / PG battery containing a 20% DMOHC and 80% DEC mixed blend ratio cycled at 3.9 V at an operating temperature of 85 °C retained more than 95% of its initial capacity after exceeding 100 cycles. As seen in Figures 22A and 22B, the Ni83 / PG battery containing an electrolyte with a solvent blend of DMOHC and DEC functioned equivalently to, or better than, the baseline electrolyte system at C / 3 and 85 °C when equilibrated at 3.8 V and 3.9 V, and no gas accumulation was demonstrated.

[0135] ·Example 16 - Preparation Method The general synthesis for preparing the compound of formula (I) is summarized in Scheme 1, and Table 2 summarizes various compounds synthesized by the general process. Scheme 1 [Chemical Formula] Pyridine, DCM 0 °C - Ambient temperature [Table 2]

[0136] To a dried 1000 mL round-bottom flask, the corresponding 1,2-diol (1 equivalent, 150 mmol) and pyridine (2.5 equivalents, 375 mmol) were added. Subsequently, the flask was purged with argon. Then, the 1,2-diol and pyridine were dissolved in anhydrous dichloromethane (DCM, 200 mL). The flask was cooled in an ice bath, and methyl chloroformate (2.5 equivalents, 375 mmol) was added dropwise in 5 mL portions over 3 hours. Subsequently, the reaction mixture was warmed to ambient temperature and stirred overnight. The next day, the reaction mixture was precipitated by the addition of diethyl ether (250 mL), and then vacuum filtered to remove solid pyridine-HCl. Then, the clear off-white liquid of the filtrate was evaporated by a rotary evaporator to remove the excess solvent, and the crude product was obtained as a viscous liquid. Then, the crude material was purified by flash column chromatography using silica gel as the stationary phase and eluting with 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 was isolated as a colorless transparent viscous liquid in a yield of up to 70%. Then, the product was dried over calcium hydride in a glove box filled with argon to a moisture level of less than 20 ppm. Then, the product was filtered through a 0.2 μm PTFE membrane to obtain the final DMOHC derivative.

[0137] Certain embodiments of the present invention have been described, but these embodiments are presented 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 can be embodied in various other forms. Further, various omissions, substitutions, and changes can be made to the systems and methods described herein without departing from the spirit of the present disclosure. The appended claims and their equivalents are intended to embrace forms or modifications that are considered to be within the scope and spirit of the present disclosure. Accordingly, the scope of the present invention is defined only by reference to the appended claims.

[0138] Features, materials, characteristics, or groups described in connection with a particular aspect, embodiment, or example are applicable to any other aspect, embodiment, or example described in this section or elsewhere in this specification, unless they are incompatible therewith. It is to be understood that all features (including any of the appended claims, abstract, and drawings) disclosed in this specification, 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 inconsistent. The protection is not limited to the details of any of the foregoing embodiments. The protection extends to any novel one, or any novel combination, of the features disclosed in this specification (including any of the appended claims, abstract, and drawings), or to any novel one, or any novel combination, of the steps of any method or process disclosed.

[0139] Furthermore, certain features described in the context of separate embodiments of the present disclosure can also be implemented in combination in a single embodiment. Conversely, the various features described in the context of a single embodiment can also be implemented separately, or in any suitable combination of components, in a plurality of embodiments. Moreover, although features may be described as acting in a particular combination, one or more features from a claimed combination may, in some cases, be deleted from the combination, and the combination may be claimed as a modification of the components of the combination or of the components of the combination.

[0140] Moreover, while operations in a particular order may be depicted in the drawings or described herein, such operations need not be performed in the particular order or sequential order shown to achieve the desired result, nor do all operations need to be performed. Other operations not illustrated or described may be incorporated into the exemplary methods and processes. For example, one or more additional operations can be performed before, after, simultaneously with, or between any of the described operations. Further, in other embodiments, the operations may be rearranged or reordered. Those skilled in the art will understand that in some embodiments, the actual steps taken in the exemplary and / or disclosed processes may differ from those shown in the drawings. Depending on the embodiment, certain steps among the above-described steps may be deleted, and other steps may be added. Additionally, the features and attributes of the particular embodiments disclosed above can be combined in different ways to form additional embodiments, all of which are within the scope of the present disclosure. Also, the separation of the various system components in the above embodiments should not be understood to be required in all embodiments, and it should be understood that the described components and systems can generally be integrated together into a single product or packaged into multiple products. For example, any of the components for an energy storage system described herein can be installed separately or integrated together (e.g., packaged together or attached together) to form an energy storage system.

[0141] For purposes of the present disclosure, certain aspects, advantages, and novel features are described herein. Not all such advantages can necessarily be achieved in accordance with any particular embodiment. Thus, for example, one skilled in the art will recognize that the present disclosure may be embodied or practiced in a manner that achieves one advantage or group of advantages taught herein without necessarily achieving other advantages that may be taught or suggested herein.

[0142] Conditional language such as "can," "could," "might," or "may" generally conveys that a particular embodiment includes a particular feature, element, and / or step, but other embodiments do not, unless otherwise specified or understood in a different sense within the context in which it is used. Thus, such conditional language generally does not mean that a feature, element, and / or step is necessarily required in one or more embodiments, or that one or more embodiments necessarily include logic for determining whether these features, elements, and / or steps are included in or should be performed in any particular embodiment, regardless of the presence or absence of user input or prompts.

[0143] Conjunctive language such as the phrase "at least one of X, Y, and Z" is understood in the context in which it is generally used to convey that an item, term, etc. can be either X, Y, or Z, unless otherwise specified. Thus, such conjunctive language is generally not intended to mean that a particular embodiment requires the presence of at least one X, at least one Y, and at least one Z.

[0144] Language used herein to indicate a degree, such as the terms "about," "approximately," "substantially," and "nearly," represents a value, amount, or metric that is close to a defined value, amount, or metric that still performs the desired function or achieves the desired result. For example, the terms "about," "approximately," "substantially," and "nearly" can refer to an amount within less than 10%, less than 5%, less than 1%, less than 0.1%, and less than 0.01% of a defined amount, depending on the desired function or desired result.

[0145] The scope of the present disclosure is not intended to be limited by the specific disclosure of the preferred embodiments in this section or elsewhere in this specification, but rather may be defined by the claims, as presented in this section or elsewhere in this specification, or as may be presented in the future. The language of the claims should be interpreted broadly based on the language used in the claims and not limited to the examples described in this specification or during the application examination, and these examples are to be construed as non-exclusive.

Claims

1. A cathode, an anode, a separator disposed between the cathode and the anode, and an electrolyte containing a solvent and an alkali metal salt An energy storage device comprising: the solvent being represented by formula (I): 【Chemical 19】 (wherein: R 1 and R 2 are each independently optionally substituted C 1 to 12 alkyl, R 3 is optionally substituted C 1 to 12 alkylene) An energy storage device comprising a compound represented by.

2. R 1 and R 2 are each independently selected from the group consisting of optionally substituted methyl, optionally substituted ethyl, optionally substituted propyl, optionally substituted butyl, optionally substituted isopropyl, optionally substituted isobutyl, and optionally substituted sec-butyl, The energy storage device according to claim 1.

3. The optional substituents R 1 and R 2 are each independently selected from at least one halogen, The energy storage device according to claim 1 or 2.

4. The optional substituent R 3 is selected from the group consisting of at least one C 1 to 12 alkyl, C 1 to 12 haloalkyl, halogen, and combinations thereof, The energy storage device according to any one of claims 1 to 3.

5. R 3 is ethylene optionally substituted or propylene optionally substituted, the energy storage device according to any one of claims 1 to 4.

6. The compound is of formula (Ia): 【Chemical formula 20】 (wherein R 4 , R 5 , R 6 and R 7 are each independently selected from the group consisting of -H, halogen, C 1 to 12 alkyl, and C 1 to 12 haloalkyl) represented by, the energy storage device according to any one of claims 1 to 5.

7. R 4 , R 5 , R 6 and R 7 are each independently -H, CH 3 -, CH 3 CH 2 -, CH 3 CH 2 CH 2 -, CH 3 CH 2 CH 2 CH 2 -, (CH 3 ) 2 CH -, CH 3 CH 2 CH(CH 3 ) -, (CH 3 ) 3 C -, -CF 3 , -CHF 2 , CH 2 F, -CH 2 CF 3 , -CH 2 CHF 2 , -CH 2 CH 2 F, -CH 2 CH 2 Cl, and -CH 2CF 2 CF 3 The energy storage device according to claim 6, selected from the group consisting of

8. R 4 is, -H, CH 3 -, CH 3 CH 2 -, CH 3 CH 2 CH(CH 3 ), (CH 3 ) 3 C-, and -CF 3 The energy storage device according to claim 6 or 7, selected from the group consisting of

9. R 5 is, -H, CH 3 -, CH 3 CH 2 -, CH 3 CH 2 CH(CH 3 ), (CH 3 ) 3 C-, and -CF 3 The energy storage device according to any one of claims 6 to 8, selected from the group consisting of

10. R 6 is, -H, CH 3 -, CH 3 CH 2 -, CH 3 CH 2 CH(CH 3 ), (CH 3 ) 3 C-, and -CF 3 The energy storage device according to any one of claims 6 to 9, selected from the group consisting of

11. R 7 is, -H, CH 3 -, CH 3 CH 2 -, CH 3 CH 2 CH(CH 3 ), (CH 3 ) 3 C-, and -CF 3The energy storage device according to any one of claims 6 to 10, selected from the group consisting of.

12. wherein the compound is of formula (Ib): 【Chemical formula 21】 (wherein R 8 、R 9 、R 10 、R 11 、R 12 、and R 13 are each independently selected from the group consisting of -H, halogen, C 1 to 12 alkyl, and C 1 to 12 haloalkyl) The energy storage device according to any one of claims 1 to 5, represented by.

13. The compound of formula (I) is 【Chemical formula 22】 The energy storage device according to any one of claims 1 to 5, selected from the group consisting of.

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 according to claim 15, wherein the lithium salt is LiFSI.

17. The energy storage device according to any one of claims 1 to 16, wherein the electrolyte further comprises a second solvent selected from the group consisting of 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), butyrolactone (GBL), and combinations thereof.

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

1.

19. The energy storage device according to any one of claims 1 to 18, configured to provide a retention rate of at least 96% of the initial capacity after 2000 cycles when operated at 3.0 V to 4.3 V.

20. The energy storage device according to any one of claims 1 to 19, configured to provide a retention rate of more than 99% of the initial capacity after 2000 cycles when operated at 3.0 V to 3.8 V at a temperature of at least 70 °C.

21. A method of manufacturing an energy storage device, comprising: disposing a cathode, an anode, a separator disposed between the cathode and the anode, and an electrolyte in a housing; the electrolyte comprising a solvent and an alkali metal salt, the solvent having the formula (I): 【Chemical Formula 23】 (wherein: R 1 and R 2 are each independently optionally substituted C 1 to 12 alkyl, and R 3 is optionally substituted C 1 to 12which is an alkylene) A method comprising a compound represented by

Images