Electrolytes for fast-charging batteries

Abstract

Disclosed herein is an electrolyte solution comprising: (a) about 5 wt % to about 60 wt % of a fluorinated ester; (b) greater than 0 wt % to less than 100 wt % of at least one solvent selected from fluoroethylene carbonate, difluoroethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl (2,2,2-trifluoroethyl) carbonate, propylene carbonate, trifluoropropylene carbonate, butylene carbonate, methyl acetate (MA), ethyl acetate (EA), methyl propanoate (MP); (c) at least one salt; wherein the wt % is calculated based on a total weight of a) and b); and wherein the electrolyte solution is substantially free of ethylene carbonate (EC). Also disclosed are batteries comprising such electrolytes. Also disclosed are methods of making the disclosed herein electrolytes and batteries.

Description

ELECTROLYTES FOR FAST-CHARGING BATTERIESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is an International Application that claims the priority benefit of U.S. Provisional Application Number 63 / 592,443, filed October 23, 2023, the content of which is incorporated by reference in their whole entirety.STATEMENT ACKNOWLEDGING GOVERNMENT SUPPORT

[0002] This invention was made with government support under Grant No. DE- AC05-76RL01830 awarded by the Department of Energy. The government has certain rights in the invention.ACKNOWLEDGEMENT

[0003] The development of this invention was funded in part by The Welch Foundation under grant F-1254.TECHNICAL FIELD

[0004] This application relates generally to electrolytes for fast-charging batteries.BACKGROUND

[0005] With the rapid increase in portable electronics and the global push towards vehicle electrification and smart grids, there is an increasing demand for large-scale, sustainable, eco-friendly, safe electrochemical energy storage systems (such as batteries, for example) with high energy / power density.

[0006] With the employment of high-energy-density, high-nickel layered oxide cathodes and silicon-graphite composite anodes, the driving range of state-of-the-art electric vehicles (EVs) has been elevated to more than 350 miles, which is comparable to gasoline-based vehicles. However, driving range anxiety remains prevalent among EV customers due to known issues with Li-based batteries (LIB). For example, current LIBs have unsatisfactory fast-charging capabilities primarily due to the inferior Li+ion intercalation kinetics at the graphite-based anode interface and the limited conductivity of the electrolyte. Consequently, the charge of LIBs typically takes more than 40 minutes, even at supercharge stations, which limits the maximum daily driving range of EVs. Further, the performance of LIBs can be largelyaffected by the environmental temperature due to poor Li+ion transport kinetics at the interfaces and poor electrolyte conductivity at low temperatures. Therefore, the driving range of EVs will be greatly compromised during winter and in regions of high latitudes or altitudes.

[0007] To improve the operation of LIBs under extreme operating conditions, particularly at fast-charging rates and / or at low temperatures, various strategies have been developed, such as cathode microstructure engineering, anode morphology and size control, and novel electrolyte design.

[0008] Previously, several electrolytes have been proposed, including high- concentration electrolytes, localized high-concentration electrolytes, dual-salt electrolytes, and electrolytes with fluorinated solvents. Despite the significantly improved performances, current electrolytes still suffer from several drawbacks for fast charging, hindering their practical viability. First, most advanced electrolytes contain expensive lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) or lithium bis(fluorosulfonyl)imide (LiFSI) salts, leading to a significant increase in the cost when compared to LiPFe-based conventional electrolytes. Second, a majority of electrolytes are based on fluorinated ethers as the electrolyte skeleton, which not only greatly increases the cost but also poses challenges of compatibility with some of the currently used anodes, for example, the graphite anode. Third, in comparison, most carbonate-based fast-charging electrolytes are compatible with graphite anode but rely on the use of ethylene carbonate (EC) to generate a favorable solidelectrolyte interphase (SEI). Unfortunately, the high solvation energy and melting point of EC make it an unideal choice under harsh operating conditions, particularly extra fast charging (XFC) in < 15 min and / or at sub-zero temperatures.

[0009] Therefore, stable low-cost electrolytes that can be operated under extreme conditions and allow quick charge are urgently needed. These needs and other needs are at least partially satisfied by the present disclosure.

[0010] The development of this invention was funded in part by The Welch Foundation under grant F-1254.SUMMARY

[0011] The present disclosure is directed to an electrolyte solution comprising: (a) about 5 wt % to about 60 wt % of a fluorinated ester; (b) greater than 0 wt % to lessthan 100 wt % of at least one solvent selected from fluoroethylene carbonate, difluoroethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl (2,2,2-trifluoroethyl) carbonate, propylene carbonate, trifluoropropylene carbonate, butylene carbonate, methyl acetate (MA), ethyl acetate (EA), methyl propanoate (MP); (c) at least one salt; wherein the wt % is calculated based on a total weight of a) and b); and wherein the electrolyte solution is substantially free of ethylene carbonate (EC).

[0012] In further aspects, the fluorinated ester comprises methyl trifluoroacetate (MTFA), ethyl trifluoroacetate (ETFA), methyl 3,3,3-trifluoropropionate (MTFP), 2,2,2-trifluoroethyl acetate (TFEA), 2,2,2-trifluoroethyl propionate (TFEP), methyl difluoroacetate (MDFA), ethyl difluoroacetate (EDFA), methyl 2,3,3,3-tetrafluoro propionate (MTFP), methyl pentafluoropropionate (MPFP), 2,2,2-trifluoroethyl butyrate (TFEB), trifluoroethyl trifluoroacetate (TFETFA) or any combination thereof.

[0013] While in still further aspects, the at least one salt comprises lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium bis(oxalato)borate (LiBOB), LiPF6, LiAsF6, LiBF4, LiCF3SO3, LiCIO4, lithium difluoro oxalato borate anion (LiDFOB), lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide (LiTDI), or any combination thereof.

[0014] In further aspects, disclosed herein is a secondary battery comprising: a first electroactive surface configured to behave as an anode, a second electroactive surface configured to behave as a cathode; and an electrolyte solution of any one of the disclosed herein examples.

[0015] In yet still, further aspects, the disclosed herein battery exhibits a charging rate of up to 4C with a cycle life of at least 500 cycles or at least 1000 cycles.

[0016] In yet still, further aspects, the disclosed herein battery exhibits a Coulombic efficiency greater than about 98% over at least about 500 cycles at a charge rate of up to 4C.

[0017] Additional advantages will be set forth in part in the description that follows, and in part will be obvious from the description or can be learned by practice of the aspects described below. The advantages described below will be realized and attained by means of the chemical compositions, methods, and combinations thereof, particularly pointed out in the appended claims. It is to be understood thatboth the foregoing general description and the following detailed description are exemplary and explanatory only and is not restrictive of the invention, as claimed.BRIEF DESCRIPTION OF DRAWINGS

[0018] FIGURES 1A-1 D depict NMR spectra of1H,13C, and19F of pure solvents DMC, FEC, MA, and TFMA.

[0019] FIGURES 2A-2D depict1H DOSY-NMR spectra of LP57 (FIG. 2A), FCEO (FIG. 2B), FCE20-MA (FIG. 2C), and FCE20 (FIG. 2D).

[0020] FIGURES 3A-3D show19F DOSY-NMR spectra of LP57 (FIG. 3A), FCEO (FIG. 3B), FCE20-MA (FIG. 3C), and FCE20 (FIG. 3D).

[0021] FIGURES 4A-4B show a cycling performance (FIG. 4A) and coulombic efficiency (FIG. 4B) of Gr | NMC811 coin full cells cycled between 2.5 and 4.25 V at a charge-discharge rate of 1 C-1 C at room temperature (~ 23 °C). 1 C equals 180 mA g~1-

[0022] FIGURES 5A-5B show SEM images showing the morphologies of plated Li (4 mA h cm-2) on Cu foil in Li | Cu cells with LP57 (FIG. 5A ) and FCE20 (FIG. 5B) electrolytes.

[0023] FIGURE 5C shows a Coulombic efficiency measurement based on Li | Cu cells with LP57 and FCE20 electrolytes.

[0024] FIGURE 5D shows formation cycle charge-discharge curves of Li | NMC811 half cells cycled with LP57 and FCE20 electrolytes at a charge-discharge rate of C / 10-C / 10.

[0025] FIGURE 5E shows a cycling performance of Li | NMC811 half cells cycled with the FCE20 electrolyte at a charge-discharge rate of C / 3-C / 3.

[0026] FIGURES 6A-6B show LSV measurements of carbon-coated Al | Li cells with LP57 and FCE20 electrolytes at a rate of 0.05 mV s-1(FIG. 6A) and a cycling performance of Gr | NMC900505 pouch full cells with LP57 and FCE20 electrolytes at a charge-discharge rate of C / 3-C / 3 (FIG. 6B).

[0027] FIGURES 7A-7D depict a 1stcycle (FIG. 7A) and a 3rdcycle (FIG. 7B) charge-discharge curves of Gr | NMC811 coin full cells with LP57 and FCE20 electrolytes cycled at a charge-discharge rate of C / 10-C / 10 at -20 °C; Rate performances (FIG. 7C) and Coulombic efficiencies (FIG. 7D) of Gr | NMC811 coin full cells with LP57 and FCE20 electrolytes at -20 °C.

[0028] FIGURES 8A-8C depict photographic images recording the combustion of glass fiber strips immersed with LP57 and FCE20 electrolytes (FIG. 8A); photographic images of glass fiber strips after the combustion (FIG. 8B); and DSC measurements of NMC811 cathode charged to 240 mA h g-1with LP57 and FCE20 electrolytes (FIG. 8C).

[0029] FIGURES 9A-9J depict the charge and discharge profiles of 1stand 4thcycles in pouch full cells with different electrolyte formulations as indicated. The cells were cycled between 2.5 and 4.25 V at a charge-discharge rate of 4C-2C at ~ 33 °C.

[0030] FIGURES 10A-10J show the dQ dV-1plot of 1stand 4thcycles in pouch full cells with different electrolyte formulations as indicated. The cells were cycled between 2.5 and 4.25 V at a charge-discharge rate of 4C-2C at ~ 33 °C.

[0031] FIGURES 11A-11 B show the dQ cN^ plot of 1stand 4thcycles in pouch full cells with different electrolyte formulations (FIG. 11 A); a zoom-in version of the dQ dV-1plots (FIG. 11 B). The cells were cycled between 2.5 and 4.25 V at a chargedischarge rate of 4C-2C at ~ 33 °C.

[0032] FIGURES 12A-12J show cycling performances of Gr | NMC811 pouch full cells between 2.5 and 4.25 V at a charge-discharge rate of 4C-2C at ~ 33 °C with different electrolytes injected as indicated.

[0033] FIGURE 13 shows cycling performances of different electrolyte formulations in pouch full cells.

[0034] FIGURES 14A-14D show cycling performances of pouch full cells with FCE20 electrolyte (FIG. 14A), Coulombic efficiency during cycling (FIG. 14B), Nyquist plots of Gr | NMC811 cells with FCE20 electrolyte after 1 ,000 cycles and after 100 cycles (inset) (FIG. 14C), and a schematic drawing of the pouch full cell configuration according to one aspect (FIG. 14D).

[0035] FIGURES 15A-15B depict a graphite anode electrode from the cycled graphite pouch cell with FCE20 electrolyte (left) (FIG. 15A) and LP57 electrolyte (FIG. 15B). SEM images of the cycled graphite electrodes from the pouch cells with FCE20 (upper right) and LP57 (lower right).

[0036] FIGURES 16A-16D show TOF-SIMS characterization of the cycled NMC81 1 cathode electrodes retrieved from the pouch full cells in LP57 and FCE20 electrolytes after 1 ,000 cycles. FIG. 16A shows normalized depth profiles of selectedorganics and inorganics secondary-ion fragments, illustrating the distinct architecture of cathode-electrode interphases. 3D visualization of selected secondary-ion fragments (FIG. 16B) and overlap plots with PO2- inorganic fragment as the outer layer (yellow) and C2HO (blue) organic species as the inner layer, both covering the top of the bulk of the cathode material, which is represented by62Ni_in green color (FIG. 16C). FIG. 16D shows the integrated intensity of selected secondary-ion species on the surface of cycled cathode particles.

[0037] FIGURES 17A-17C show an illustration of the different region-of-interest based on TOF-SIMS mapping (FIG. 17A); 63“ and60Ni“ peak intensity comparison (FIG. 17B) and C2F-, C2O“, and NiFa- peak intensity comparison between different regions (FIG. 16C).

[0038] FIGURES 18A-18C show TOF-SIMS characterization of the cycled graphite electrodes retrieved from the pouch full cells in LP57 and FCE20 electrolytes after 1 ,000 cycles. Normalized depth profiles of selected secondary-ion fragments on the outer “dead Li” layer (FIG. 18A) and the inner graphite layer (FIG. 18B). Probing depth profile for characterizing the surface roughness on the surface of “dead Li” layer and graphite layer (FIG. 18C). The breadth of the peak area serves as an indicator of the depth of the cavity on the surface of SEI. A narrower peak corresponds to a smoother surface.

[0039] FIGURES 19A-19B show an integrated yield of negative secondary-ion fragments on the surface of the cycled “dead” Li layer and bottom graphite layer of the anode after 1 ,000 cycles in LP57 and FCE20 electrolytes, as indicated.

[0040] FIGURES 20A-20E show the Molecular Dynamic Simulation results of LP57 and FCE20 electrolytes (FIG. 20A)._7Li and19F nuclear magnetic resonance (NMR) spectroscopy data of FCE0, FCE20, and FCE65 electrolytes (FIG. 20B). FTIR spectra of various FCEs and pure solvents (FIG. 20C). Illustration of the solvation structure of the LP57 and FCE20 electrolytes (FIG. 20D). Solubility of LiPFe in various FCEs and pure solvents (FIG. 20E).

[0041] FIGURE 21 shows the Molecular Dynamic Simulation results of the FCE65 electrolyte.

[0042] FIGURES 22A-22B show FTIR spectra of pure solvents and various FCEs with different LiPFe concentrations. SDMC and FDMC refer to solvated and free DMC, respectively.

[0043] FIGURES 23A-23D show FTIR spectra of electrolytes containing different LiPFe concentrations in DMC and FEC electrolytes.

[0044] FIGURES 24A-24B show FTIR spectra of pure solvents, including DMC, FEC and MA, electrolytes containing different concentrations of LiPFe in MA, and MA-based FCEs, including FCE25-MA and FCE65-MA.

[0045] FIGURE 25 shows the solubility of LiPFe in a pure DMC, MTFA, and a mixture of DMC and MTFA solvents.

[0046] FIGURE 26 shows the Comparison of LiPFe salt solubility in MTFA-based and 1 ,1 ,2,2-tetrafluoroethylene 2,2,3,3-tetrafluoropropyl ether (TTE)-based electrolytes.

[0047] FIGURE 27 shows the Ionic conductivity measurement of FCE20 with different concentrations of LiPFe and LP57 at 25 °C.

[0048] The accompanying figures, which are incorporated in and constitute a part of this specification, illustrate several aspects described below.DETAILED DESCRIPTION

[0049] The present invention can be understood more readily by reference to the following detailed description, examples, drawings, and claims, and their previous and following description. However, before the present articles, systems, and / or methods are disclosed and described, it is to be understood that this invention is not limited to the specific or exemplary aspects of articles, systems, and / or methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

[0050] The following description of the invention is provided as an enabling teaching of the invention in its best, currently known aspect. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the invention described herein while still obtaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be obtained by selecting some of the features of the present invention without utilizing other features. Accordingly, those of ordinary skill in the pertinent art will recognize that many modifications and adaptations to the present invention are possible and may even be desirable incertain circumstances and are a part of the present invention. Thus, the following description is again provided as illustrative of the principles of the present invention and not in limitation thereof.DEFINITIONS

[0051] As used herein, the terms "optional" or "optionally" mean that the subsequently described event or circumstance can or cannot occur and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0052] It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate aspects, can also be provided in combination in a single aspect. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single aspect, can also be provided separately or in any suitable subcombination.

[0053] As used in the description and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, a reference to “a solvent” includes not only one but also two or more such solvents, and a reference to “a battery” includes not only one but also two or more such batteries and the like.

[0054] Throughout the description and claims of this specification, the word "comprise" and other forms of the word, such as "comprising" and "comprises," are open, non-limiting terms and mean “including but not limited to,” and are not intended to exclude, for example, other additives, segments, integers, or steps. Furthermore, it is to be understood that the terms “comprise,” “comprising,” and “comprises” as they relate to various aspects, elements, and features of the disclosed invention also include the more limited aspects of "consisting essentially of" and "consisting of."

[0055] For the terms "for example" and "such as," and grammatical equivalences thereof, the phrase "and without limitation" is understood to follow unless explicitly stated otherwise. It is further understood that these phrases are used for explanatory purposes only. It is further understood that the term "exemplary," as used herein, means "an example of" and is not intended to convey an indication of a preferred or ideal aspect.

[0056] The expressions "ambient temperature" and "room temperature" as used herein are understood in the art and refer generally to a temperature from about 20 °C to about 35 °C.

[0057] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Furthermore, when numerical ranges of varying scope are set forth herein, it is contemplated that any combination of these values, inclusive of the recited values, may be used. Further, ranges can be expressed herein as from “about” one particular value and / or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and / or to the other particular value.

[0058] Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint and independently of the other endpoint. Unless stated otherwise, the term “about” means within 5% (e.g., within 2% or 1%) of the particular value modified by the term “about.”

[0059] Throughout this disclosure, various aspects of the invention can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, a description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within that range, for example, 1 , 2, 2.7, 3, 4, 5, 5.3, 6 and any whole and partial increments therebetween. This applies regardless of the breadth of the range.

[0060] In still further aspects, when the specific values are disclosed between two end values, it is understood that these end values can also be included.

[0061] In still further aspects, when the range is given and exemplary values are provided, it is understood that any ranges can be formed between any exemplary values within the broadest range.

[0062] As used herein, the term “composition” is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product that results, directly or indirectly, from a combination of the specified ingredients in the specified amounts.

[0063] References in the specification and concluding claims to parts by weight of a particular element or component in a composition denote the weight relationship between the element or component and any other elements or components in the composition or article for which a part by weight is expressed. Thus, in a mixture containing 2 parts by weight of component X and 5 parts by weight, components Y, X, and Y are present at a weight ratio of 2:5 and are present in such a ratio regardless of whether additional components are contained in the mixture.

[0064] A weight percent (wt.%) of a component, unless specifically stated to the contrary, is based on the total weight of the formulation or composition in which the component is included.

[0065] It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present. Other words used to describe the relationship between elements or layers should be interpreted in a like fashion (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," "on" versus "directly on").

[0066] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0067] It will be understood that the terms "first," "second," etc., may be used herein to describe various elements, components, regions, layers, and / or sections. These elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could betermed a second element, component, region, layer, or section without departing from the teachings of example embodiments.

[0068] As used herein, the term "substantially" means that the subsequently described event or circumstance completely occurs or that the subsequently described event or circumstance generally, typically, or approximately occurs.

[0069] Still further, the term "substantially" can, in some aspects, refer to at least about 90 %, at least about 95 %, at least about 99 %, or about 100 % of the stated property, component, composition, or other condition for which substantially is used to characterize or otherwise quantify an amount.

[0070] In other aspects, as used herein, the term “substantially free,” when used in the context of a composition or component of a composition that is substantially absent, is intended to refer to an amount that is then about 1 % by weight, e.g., less than about 0.5 % by weight, less than about 0.1 % by weight, less than about 0.05 % by weight, or less than about 0.01 % by weight of the stated material, based on the total weight of the composition.

[0071] As used herein, the terms “substantially identical reference composition,” “substantially identical reference article,” or “substantially identical reference electrochemical cell” refer to a reference composition, article, or electrochemical cell comprising substantially identical components in the absence of an inventive component. In another exemplary aspect, the term "substantially," in, for example, the context "substantially identical reference composition," or “substantially identical reference article,” or “substantially identical reference electrochemical cell,” refers to a reference composition, article, or an electrochemical cell comprising substantially identical components and wherein an inventive component is substituted with a common in the art component.

[0072] The organic moieties mentioned when defining variable positions within the general formulae described herein (e.g., the term “halogen”) are collective terms for the individual substituents encompassed by the organic moiety. The prefix Cn-m preceding a group or moiety indicates, in each case, the possible number of carbon atoms in the group or moiety that follows.

[0073] The term “ion,” as used herein, refers to any molecule, portion of a molecule, a cluster of molecules, molecular complex, moiety, or atom that contains a charge (positive, negative, or both at the same time within one molecule, cluster ofmolecules, molecular complex, or moiety (e.g., zwitterions)) or that can be made to contain a charge. Methods for producing a charge in a molecule, a portion of a molecule, a cluster of molecules, a molecular complex, moiety, or atom are disclosed herein and can be accomplished by methods known in the art, e.g., protonation, deprotonation, oxidation, reduction, alkylation, acetylation, esterification, deesterification, hydrolysis, etc.

[0074] The term “anion” is a type of ion and is included within the meaning of the term “ion.” An “anion” is any molecule, portion of a molecule (e.g., zwitterion), a cluster of molecules, molecular complex, moiety, or atom that contains a net negative charge or that can be made to contain a net negative charge. The term “anion precursor” is used herein to specifically refer to a molecule that can be converted to an anion via a chemical reaction (e.g., deprotonation).

[0075] The term “cation” is a type of ion and is included within the meaning of the term “ion.” A “cation” is any molecule, portion of a molecule (e.g., zwitterion), a cluster of molecules, molecular complex, moiety, or atom containing a net positive charge or that can be made to contain a net positive charge. The term “cation precursor” is used herein to specifically refer to a molecule that can be converted to a cation via a chemical reaction (e.g., protonation or alkylation).

[0076] The term “electrolyte composition,” as used herein, refers to a chemical composition suitable for use as an electrolyte in an electrochemical cell.

[0077] The term “electrolyte salt,” as used herein, refers to an ionic salt that is at least partially soluble in an electrolyte and that at least partially dissociates into ions in the electrolyte.

[0078] The term “anode” refers to an electrode of an electrochemical cell at which oxidation occurs. In a galvanic cell, such as a battery, the anode is the negative electrode. In a secondary (i.e., rechargeable) battery, the anode is the electrode at which oxidation occurs during discharge and reduction occurs during charging.

[0079] The term “cathode” refers to an electrode of an electrochemical cell at which reduction occurs. In a galvanic cell, such as a battery, the cathode is the positive electrode. In a secondary (i.e., rechargeable) battery, the cathode is the electrode at which reduction occurs during discharge and oxidation occurs during charging.

[0080] In still further aspects, the term state of charge (SOC) refers to the level of charge of a battery relative to its capacity. SOC is usually expressed as apercentage (0% = empty; 100% = full). An alternative form of the same measure can be referred to as a depth of discharge (DOD), calculated as 100 - SoC (100% = empty; 0% = full). SOC is normally used when discussing the current state of a battery in use, while DOD is most often seen when discussing the lifetime of the battery after repeated use. In still further aspects, the term “deep discharge” refers to a condition where the state of charge (SOC) of the battery is substantially 0%. Yet, in other aspects, the term “deep charge” refers to a condition where the SOC of the battery is substantially 100%.

[0081] As used herein, the term “substituted” means that a hydrogen atom is removed and replaced by a substituent. It is contemplated to include all permissible substituents of organic compounds. As used herein, the phrase "optionally substituted" means unsubstituted or substituted. It is understood that substitution at a given atom is limited by valency. In a broad aspect, the permissible substituents include acyclic and cyclic, branched and unbranched, carbocyclic and heterocyclic, and aromatic and nonaromatic substituents of organic compounds. Illustrative substituents include, for example, those described below. The permissible substituents can be one or more and the same or different for appropriate organic compounds. For purposes of this disclosure, the heteroatoms, such as nitrogen, can have hydrogen substituents and / or any permissible substituents of organic compounds described herein that satisfy the valencies of the heteroatoms. This disclosure is not intended to be limited in any manner by the permissible substituents of organic compounds. Also, the terms “substitution” or “substituted with” include the implicit proviso that such substitution is in accordance with a permitted valence of the substituted atom and the substituent and that the substitution results in a stable compound, e.g., a compound that does not spontaneously undergo transformation such as by rearrangement, cyclization, elimination, etc. In still further aspects, it is understood that when the disclosure describes a group being substituted, it means that the group is substituted with one or more (i.e., 1 , 2, 3, 4, or 5) groups as allowed by valence selected from alkyl, halogenated alkyl, alkoxy, alkenyl, alkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, nitro, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, or thiol, as described below.

[0082] “Z1,” “Z2,” “Z3,” and “Z4” are used herein as generic symbols to represent various specific substituents. In certain aspects, the generic symbols to representvarious specific substituents can be marked as “R1,” “R2,” “R3,” or “Rn” wherein n is a subsequent number of substituents. These symbols can be any substituent, not limited to those disclosed herein, and when they are defined to be certain substituents in one instance, they can, in another instance, be defined as some other substituents.

[0083] A dashthat is not between two letters or symbols is used to indicate a point of attachment for a substituent. For example, -(C=O)NH2 is attached through carbon of the keto (C=O) group.

[0084] The term “aliphatic,” as used herein, refers to a non-aromatic hydrocarbon group and includes branched and unbranched, alkyl, alkenyl, or alkynyl groups. As used herein, the term "Cn-Cm alkyl" (or “Cn-m”) employed alone or in combination with other terms refers to a saturated hydrocarbon group that may be straight-chain or branched, having n to m carbons. It is understood that the terms Cn-m and Cn-Cm can be used interchangeably and just to show that the specific compound has between n to m carbons. Unless otherwise specified, C1-C24 (e.g., C1-C22, C1-C20, C1-C18, C1- C16, C1-C14, C1-C12, C1-C10, Ci-Cs, Ci-Ce, or C1-C4) alkyl groups are intended. Examples of alkyl moieties include, but are not limited to, chemical groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, sec-butyl; higher homologs such as 2-methyl-l-butyl, n-pentyl, 3-pentyl, n-hexyl, 1 ,2,2-trimethylpropyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, eicosyl, tetracosyl, and the like. The alkyl group can also be substituted or unsubstituted. Throughout the specification, “alkyl” is generally used to refer to both unsubstituted alkyl groups and substituted alkyl groups; however, substituted alkyl groups are also specifically referred to herein by identifying the specific substituent(s) on the alkyl group. The alkyl group can be substituted with one or more groups including, but not limited to, alkyl, halogenated alkyl, alkoxy, alkenyl, alkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, nitro, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, or thiol, as described below, provided that the substituents are sterically compatible and the rules of chemical bonding and strain energy are satisfied. It is further understood that throughout the specification, “alkyl” can also be referred to as a linking group of saturated hydrocarbons that are divalent radicals. In other words, in a broader description, the term “alkyls” also encompasses alkylenes.It is further understood that the term “alkyl” covers saturated hydrocarbons that are multivalent radicals.

[0085] The term "heteroaliphatic" refers to an aliphatic moiety that contains at least one heteroatom in the chain, for example, an amine, carbonyl, carboxy, oxo, thio, phosphate, phosphonate, nitrogen, phosphorus, silicon, or boron atoms in place of a carbon atom. In certain aspects, the only heteroatom is nitrogen. In certain aspects, the only heteroatom is oxygen. In certain aspects, the only heteroatom is sulfur. “Heteroaliphatic" is intended herein to include, but is not limited to, heteroalkyl, heteroalkenyl, heteroalkynyl, heterocycloalkyl, heterocycloalkenyl, and heterocycloalkynyl moieties. In certain aspects, "heteroaliphatic" is used to indicate a heteroaliphatic group (cyclic, acyclic, substituted, unsubstituted, branched, or unbranched) having 1 -20 carbon atoms. In certain aspects, the heteroaliphatic group is optionally substituted in a manner that results in the formation of a stable moiety. Nonlimiting examples of heteroaliphatic moieties are polyethylene glycol, polyalkylene glycol, amide, polyamide, polylactide, polyglycolide, thioether, and ether, alkyl-heterocycle-alkyl, -O-alkyl-O-alkyl, alkyl-O-haloalkyl, etc.

[0086] Throughout the specification, “alkyl” is generally used to refer to both unsubstituted alkyl groups and substituted alkyl groups; however, substituted alkyl groups are also specifically referred to herein by identifying the specific substituent(s) on the alkyl group.

[0087] For example, the term “halogenated alkyl” specifically refers to an alkyl group that is substituted with one or more halides, e.g., fluorine, chlorine, bromine, or iodine. “Haloalkyl” is a branched or straight-chain alkyl group substituted with 1 or more halo atoms described above, up to the maximum allowable number of halogen atoms. Examples of haloalkyl groups include but are not limited to, fluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl, trichloromethyl, pentafluoroethyl, heptafluoropropyl, difluorochloromethyl, dichlorofluoromethyl, difluoroethyl, difluoropropyl, dichloroethyl, and dichloropropyl. “Perhaloalkyl” means an alkyl group having all hydrogen atoms replaced with halogen atoms. Examples include but are not limited to trifluoromethyl and pentafluoroethyl.

[0088] The term “alkoxyalkyl” specifically refers to an alkyl group that is substituted with one or more alkoxy groups, as described below. The term “alkylamino” specifically refers to an alkyl group that is substituted with one or more aminogroups, as described below and the like. When “alkyl” is used in one instance, and a specific term such as “alkylalcohol” is used in another, it is not meant to imply that the term “alkyl” does not also refer to specific terms such as “alkylalcohol” and the like.

[0089] As used herein, "Cn-Cm alkenyl" refers to an alkyl group having one or more double carbon-carbon bonds and having n to m carbons. Alkenyls can be straight- chained or branched. Unless otherwise specified, C2-C24 (e.g., C2-C22, C2-C20, C2- C18, C2-C16, C2-C14, C2-C12, C2-C10, C2-C8, C2-C6, or C2-C4) alkenyl groups are intended. Alkenyl groups may contain more than one unsaturated bond. Examples include ethenyl, 1 -propenyl, 2-propenyl, 1 -methylethenyl, 1 -butenyl, 2-butenyl, 3- butenyl, 1 -methyl-1 -propenyl, 2-methyl-1 -propenyl, 1 -methyl-2-propenyl, 2-methyl-2- propenyl, 1 -pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1 -methyl-1 -butenyl, 2- methyl-1 -butenyl, 3-methyl-1 -butenyl, 1 -methyl-2-butenyl, 2-methyl-2-butenyl, 3- methyl-2-butenyl, 1 -methyl-3-butenyl, 2-methyl-3-butenyl, 3-methyl-3-butenyl, 1 ,1 - dimethyl-2-propenyl, 1 ,2-dimethyl-1 -propenyl, 1 ,2-dimethyl-2-propenyl, 1 -ethyl-1 - propenyl, 1 -ethyl-2-propenyl, 1 -hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, 1 -methyl-1 -pentenyl, 2-methyl-1 -pentenyl, 3-methyl-1 -pentenyl, 4-methyl-1 -pentenyl, 1 -methyl-2-pentenyl, 2-methyl-2-pentenyl, 3-methyl-2-pentenyl, 4-methyl-2-pentenyl, 1 -methyl-3-pentenyl, 2-methyl-3-pentenyl, 3-methyl-3-pentenyl, 4-methyl-3-pentenyl,1 -methyl-4-pentenyl, 2-methyl-4-pentenyl, 3-methyl-4-pentenyl, 4-methyl-4-pentenyl, 1 ,1 -dimethyl-2-butenyl, 1 ,1 -dimethyl-3-butenyl, 1 ,2-dimethyl-1 -butenyl, 1 ,2-dimethyl-2-butenyl, 1 ,2-dimethyl-3-butenyl, 1 ,3-dimethyl-1 -butenyl, 1 ,3-dimethyl-2-butenyl,1 ,3-dimethyl-3-butenyl, 2,2-dimethyl-3-butenyl, 2,3-dimethyl-1 -butenyl, 2,3-dimethyl- 2-butenyl, 2,3-dimethyl-3-butenyl, 3,3-dimethyl-1 -butenyl, 3,3-dimethyl-2-butenyl, 1 - ethyl-1 -butenyl, 1 -ethyl-2-butenyl, 1 -ethyl-3-butenyl, 2-ethyl-1 -butenyl, 2-ethyl-2- butenyl, 2-ethyl-3-butenyl, 1 ,1 ,2-trimethyl-2-propenyl, 1 -ethyl-1 -methyl-2-propenyl, 1 - ethyl-2-methyl-1 -propenyl, and 1 -ethyl-2-methyl-2-propenyL The term “vinyl” refers to a group having the structure -CH=CH2; 1 -propenyl refers to a group with the structure -CH=CH-CHs; and 2-propenyl refers to a group with the structure -CH2- CH=CH2. Asymmetric structures such as (Z1Z2)C=C(Z3Z4) are intended to include both the E and Z isomers. This can be presumed in structural formulae herein wherein an asymmetric alkene is present, or it can be explicitly indicated by the bond symbol C=C. Examples of alkenyl groups include but are not limited to, ethenyl, n-propenyl, isopropenyl, n-butenyl, seobutenyl, and the like. In various aspects, the alkenyl moiety contains 2 to 6, 2 to 4, or 2 to 3 carbon atoms. The alkenyl group can be substituted with one or more groups including, but not limited to, alkyl, halogenated alkyl, alkoxy, alkenyl, alkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, thiol, or phosphonyl, as described below. It is understood that alkenyl groups can be used as a linking group, in such aspects, the broad definition of the alkenyl group also includes divalent alkenylene groups.

[0090] As used herein, "Cn-Cm alkynyl" refers to an alkyl group having one or more triple carbon-carbon bonds and having n to m carbons. Alkynyls can be straight- chained or branched hydrocarbon moieties containing a triple bond. Unless otherwise specified, C2-C24 (e.g., C2-C24, C2-C20, C2-C18, C2-C16, C2-C14, C2-C12, C2- C10, C2-C8, C2-C6, or C2-C4) alkynyl groups are intended. Alkynyl groups may contain more than one unsaturated bond. Examples include C2-Ce-alkynyl, such as ethynyl, 1 -propynyl, 2-propynyl (or propargyl), 1 -butynyl, 2-butynyl, 3-butynyl, 1 -methyl-2- propynyl, 1 -pentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, 3-methyl-1 -butynyl, 1 - methyl-2-butynyl, 1 -methyl-3-butynyl, 2-methyl-3-butynyl, 1 ,1 -dimethyl-2-propynyl, 1 - ethyl-2-propynyl, 1 -hexynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl, 5-hexynyl, 3-methyl-1 - pentynyl, 4-methyl-1 -pentynyl, 1 -methyl-2-pentynyl, 4-methyl-2-pentynyl, 1 -methyl-3- pentynyl, 2-methyl-3-pentynyl, 1 -methyl-4-pentynyl, 2-methyl-4-pentynyl, 3-methyl-4- pentynyl, 1 ,1 -dimethyl-2-butynyl, 1 ,1 -dimethyl-3-butynyl, 1 ,2-dimethyl-3-butynyl, 2,2- dimethyl-3-butynyl, 3, 3-dimethyl-1 -butynyl, 1 -ethyl-2-butynyl, 1 -ethyl-3-butynyl, 2- ethyl-3-butynyl, and 1 -ethyl-1 -methyl-2-propynyL In various aspects, the alkynyl moiety contains 2 to 6, 2 to 4, or 2 to 3 carbon atoms. The alkynyl group can be substituted with one or more groups including, but not limited to, alkyl, halogenated alkyl, alkoxy, alkenyl, alkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, or phosphonyl, as described below.

[0091] As used herein, the term "Cn-Cm alkylene," employed alone or in combination with other terms, refers to a divalent alkyl linking group having n to m carbons. Examples of alkylene groups include, but are not limited to, ethan-1 ,2-diyl, propan- 1 ,3-diyl, propan-1 ,2-diyl, butan-1 ,4-diyl, butan-1 ,3 -diyl, butan-1 ,2-diyl, 2-methyl- propan-1 ,3-diyl, and the like. In various aspects, the alkylene moiety contains 2 to 6,2 to 4, 2 to 3, 1 to 6, 1 to 4, or 1 to 2 carbon atoms. It is understood that in certain aspects, alkylene can also be referred to as alkyl in a broader scope of the definition, with the understanding that if it is a linking group, it provides two bonds.

[0092] As used herein, the term “Cn-Cm alkoxy,” employed alone or in combination with other terms, refers to a group of formula -O-alkyl, wherein the alkyl group has n to m carbons. In other words, the term alkoxy, as used herein, is an alkyl group bound through a single, terminal ether linkage; that is, an “alkoxy” group can be defined as a group of the formula Z1-O-, where Z1is unsubstituted or substituted alkyl as defined above. Unless otherwise specified, alkoxy groups wherein Z1is a Ci- 024 (e.g., C1-C22, C1-C20, C1-C18, C1-C16, C1-C14, C1 -C12, C1 -C10, Ci-Cs, Ci-Ce, or Ci - 04) alkyl group are intended. Examples include methoxy, ethoxy, propoxy, 1 -methyl- ethoxy, butoxy, 1 -methyl-propoxy, 2-methyl-propoxy, 1 ,1 -dimethyl-ethoxy, pentoxy, 1 -methyl-butyloxy, 2-methyl-butoxy, 3-methyl-butoxy, 2,2-di-methyl-propoxy, 1 -ethylpropoxy, hexoxy, 1 ,1 -dimethyl-propoxy, 1 ,2-dimethyl-propoxy, 1 -methyl-pentoxy, 2- methyl-pentoxy, 3-methyl-pentoxy, 4-methyl-penoxy, 1 ,1-dimethyl-butoxy, 1 ,2- dimethyl-butoxy, 1 ,3-dimethyl-butoxy, 2,2-dimethyl-butoxy, 2,3-dimethyl-butoxy, 3,3- dimethyl-butoxy, 1 -ethyl-butoxy, 2-ethylbutoxy, 1 ,1 ,2-trimethyl-propoxy, 1 ,2,2- trimethyl-propoxy, 1 -ethyl-1 -methyl-propoxy, and 1 -ethyl-2-methyl-propoxy. In other aspects, an example of alkoxy groups includes methoxy, ethoxy, propoxy (e.g., n- propoxy and isopropoxy), tert-butoxy, and the like. In various aspects, the alkyl group has 1 to 6, 1 to 4, or 1 to 3 carbon atoms.

[0093] The term “cyclic group” is used herein to refer to either aryl groups or nonaryl groups ( / .e., cycloalkyl, heterocycloalkyl, cycloalkenyl, and heterocycloalkenyl groups), or both. Cyclic groups have one or more ring systems that can be substituted or unsubstituted. A cyclic group can contain one or more aryl groups, one or more non-aryl groups, or one or more aryl groups and one or more non-aryl groups. It is understood that if this cyclic group is a linking group, aryl groups can include broader scope arylenes if they behave as linking groups.

[0094] As used herein, “aryl” refers to a radical of a monocyclic or polycyclic (e.g., bicyclic or tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or 14 it electrons shared in a cyclic array) having 6-14 ring carbon atoms and zero heteroatoms provided in the aromatic ring system (“C6-14 aryl”). In some aspects, an aryl group has 6 ring carbon atoms (“Ce aryl”; e.g., phenyl). In some aspects, an aryl group has10 ring carbon atoms (“C10 aryl”; e.g., naphthyl such as 1 - naphthyl and 2-naphthyl). In some aspects, an aryl group has 14 ring carbon atoms (“Ci4 aryl”; e.g., anthracyl). “Aryl” also includes ring systems wherein the aryl ring, as defined above, is fused with one or more cycloalkyl or heterocycle groups wherein the radical or point of attachment is on the aryl ring, and in such instances, the number of carbon atoms continues to designate the number of carbon atoms in the aryl ring system. One or more fused cycloalkyl or heterocycle groups can be 4 to 7-member saturated or partially unsaturated cycloalkyl or heterocycle groups. It is understood that when an aryl group is used as a linking group, in a broad sense, it includes arylenes.

[0095] “Arylalkyl” refers to either an alkyl group as defined herein substituted with an aryl group as defined herein or to an aryl group as defined herein substituted with an alkyl group as defined herein.

[0096] The term “heterocycle” denotes saturated and partially saturated heteroatomcontaining ring radicals wherein there are 1 , 2, 3, or 4 heteroatoms independently selected from nitrogen, sulfur, boron, silicon, and oxygen. Heterocyclic rings may comprise monocyclic 3-10 membered rings, as well as 5-16 membered bicyclic ring systems (which can include bridged, fused, and spiro-fused bicyclic ring systems). It does not include rings containing -O-O-, -O-S- or -S-S- portions. Examples of saturated heterocycle groups include saturated 3- to 6-membered heteromonocyclic groups containing 1 to 4 nitrogen atoms [e.g., pyrrolidinyl, imidazolidinyl, piperidinyl, pyrrolinyl, piperazinyl] ; saturated 3 to a 6-membered heteromonocyclic group containing 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms [e.g., morpholinyl]; saturated 3 to 6- membered heteromonocyclic group containing 1 to 2 sulfur atoms and 1 to 3 nitrogen atoms [e.g., thiazolidinyl]. Examples of partially saturated heterocycle radicals include but are not limited to dihydrothienyl, dihydropyranyl, dihydrofuryl, and dihydrothiazolyl. Examples of partially saturated and saturated heterocycle groups include but are not limited to pyrrolidinyl, imidazolidinyl, piperidinyl, pyrrolinyl, pyrazolidinyl, piperazinyl, morpholinyl, tetrahydropyranyl, thiazolidinyl, dihydrothienyl, 2,3-dihydro-benzo[l,4]dioxanyl, indolinyl, isoindolinyl, dihydrobenzothienyl, dihydrobenzofuryl, isochromanyl, chromanyl, 1 ,2- dihydroquinolyl, 1 ,2,3,4-tetrahydro-isoquinolyl, 1 ,2,3,4-tetrahydro-quinolyl, 2,3,4,4a,9,9a-hexahydro-IH-3-aza-fluorenyl, 5,6,7-trihydro- 1 , 2,4-triazolo[3,4-a]isoquinolyl, 3,4-dihydro-2H-benzo[l,4]oxazinyl, benzofl, 4]dioxanyl, 2,3- dihydro-IH-l A’-benzo[d]isothiazol-6-yl, dihydropyranyl, dihydrofuryl, and dihydrothiazolyl.

[0097] “Heterocycle” also includes groups wherein the heterocyclic radical is fused / condensed with an aryl or carbocycle radical, wherein the point of attachment is the heterocycle ring. “Heterocycle” also includes groups wherein the heterocyclic oradical is substituted with an oxo group (i.e. ). For example, a partially unsaturated condensed heterocyclic group containing 1 to 5 nitrogen atoms, for example, indoline or isoindoline; a partially unsaturated condensed heterocyclic group containing 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms; a partially unsaturated condensed heterocyclic group containing 1 to 2 sulfur atoms and 1 to 3 nitrogen atoms; and a saturated condensed heterocyclic group containing 1 to 2 oxygen or sulfur atoms.

[0098] The term “fused aromatic rings” refers to systems in which two or more cyclic moieties are joined together by two or more separate covalent bonds. Exemplary fused systems include ortho-fused systems (like naphthalene, etc.) and / ortho- and peri-fused (like phenalene, etc.).

[0099] The term “heterocycle” also includes “bicyclic heterocycle.” The term “bicyclic heterocycle” denotes a heterocycle as defined herein wherein there is one bridged, fused, or spirocyclic portion of the heterocycle. The bridged, fused, or spirocyclic portion of the heterocycle can be a carbocycle, heterocycle, or aryl group as long as a stable molecule results. Unless excluded by context, the term “heterocycle” includes bicyclic heterocycles. Bicyclic heterocycle includes groups wherein the fused heterocycle is substituted with an oxo group. Non-limiting examples of bicyclic heterocycles include:

[0100] “Heterocyclealkyl” refers to either an alkyl group as defined herein substituted with a heterocycle group as defined herein or to a heterocycle group as defined herein substituted with an alkyl group as defined herein.

[0101] The term “heteroaryl” denotes stable aromatic ring systems that contain 1 , 2, 3, or 4 heteroatoms independently selected from O, N, and S, wherein the ring nitrogen and sulfur atom(s) are optionally oxidized, and the nitrogen atom(s) are optionally quartemized. Examples include, but are not limited to, unsaturated 5 to 6 membered heteromonocyclyl groups containing 1 to 4 nitrogen atoms, such as pyrrolyl, imidazolyl, pyrazolyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, pyrimidyl, pyrazinyl, pyridazinyl, triazolyl [e.g., 4H-l,2,4-triazolyl, H4-1 ,2,3-triazolyl, 2H-l,2,3-triazolyl]; unsaturated 5- to 6-membered heteromonocyclic groups containing an oxygen atom, for example, pyranyl, 2 -furyl, 3-furyl, etc.; unsaturated 5 to 6-membered heteromonocyclic groups containing a sulfur atom, for example, 2-thienyl, 3-thienyl, etc.; unsaturated 5- to 6-membered heteromonocyclic groups containing 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms, for example, oxazolyl, isoxazolyl, oxadiazolyl [e.g., 1 ,2,4-oxadiazolyl, 1 ,3,4-oxadiazolyl, 1 ,2,5-oxadiazolyl]; unsaturated 5 to 6-membered heteromonocyclic groups containing 1 to 2 sulfur atoms and 1 to 3 nitrogen atoms, for example, thiazolyl, thiadiazolyl [e.g., 1 ,2,4-thiadiazolyl, 1 ,3,4- thiadiazolyl, 1 ,2,5-thiadiazolyl] . In certain aspects, the “heteroaryl” group is an 8, 9, or 10-membered bicyclic ring system. Examples of 8, 9, or 10-membered bicyclic heteroaryl groups include benzofurazanyl, benzothiophenyl, benzothiazolyl, benzoxazolyl, quinazolinyl, quinoxalinyl, naphthyridinyl, quinolinyl, isoquinolinyl, benzofuranyl, indolyl, indazolyl, and benzotriazolyl.

[0102] “Heteroaryl alkyl” refers to either an alkyl group as defined herein substituted with a heteroaryl group as defined herein or to a heteroaryl group as defined herein substituted with an alkyl group as defined herein.

[0103] As used herein, “carbocyclic,” “carbocycle,” or “cycloalkyl” includes a saturated or partially unsaturated (i.e., not aromatic) group containing all carbon ring atoms and from 3 to 14 ring carbon atoms (“C3-14 cycloalkyl”) and zero heteroatoms in the non-aromatic ring system. In some aspects, a cycloalkyl group has 3 to 10-ring carbon atoms (“C3-10 cycloalkyl”). In some aspects, a cycloalkyl group has 3 to 9 ring carbon atoms (“C3-9 cycloalkyl”). In some aspects, a cycloalkyl group has 3 to 8-ring carbon atoms (“C3-8 cycloalkyl”). In some aspects, a cycloalkyl group has 3 to 7-ringcarbon atoms (“C3-7 cycloalkyl”). In some aspects, a cycloalkyl group has 3 to 6-ring carbon atoms (“C3-6 cycloalkyl”). In some aspects, a cycloalkyl group has 4 to 6-ring carbon atoms (“C4-6 cycloalkyl”). In some aspects, a cycloalkyl group has 5 to 6-ring carbon atoms (“C5-6 cycloalkyl”). In some aspects, a cycloalkyl group has 5 to 10 ring carbon atoms (“C5-10 cycloalkyl”). Exemplary C3-6 cycloalkyl groups include, without limitation, cyclopropyl (C3), cyclopropenyl (C3), cyclobutyl (C4), cyclobutenyl (C4), cyclopentyl (C5), cyclopentenyl (C5), cyclohexyl (Ce), cyclohexenyl (Ce), cyclohexadienyl (Ce), and the like. Exemplary C3-8 cycloalkyl groups include, without limitation, the aforementioned C3-6 cycloalkyl groups as well as cycloheptyl (C7) and cycloheptenyl (C7), cycloheptadienyl (C7), cycloheptatrienyl (C7), cyclooctyl (Cs), cyclooctenyl (Cs), and the like. Exemplary C3-10 cycloalkyl groups include without limitation, the aforementioned C3-8 cycloalkyl groups as well as cyclononyl (C9) and cyclononenyl (C9), cyclodecyl (C10), cyclodecenyl (C10), and the like. As the foregoing examples illustrate, in certain aspects, the cycloalkyl group can be saturated or can contain one or more carbon-carbon double bonds. The term “cycloalkyl” also includes ring systems wherein the cycloalkyl ring, as defined above, is fused with one heterocycle, aryl, or heteroaryl ring wherein the point of attachment is on the cycloalkyl ring, and in such instances, the number of carbons continues to designate the number of carbons in the carbocyclic ring system. The term “cycloalkyl” also includes ring systems wherein the cycloalkyl ring, as defined above, has a spirocyclic heterocycle, aryl, or heteroaryl ring wherein the point of attachment is on the cycloalkyl ring, and in such instances, the number of carbons continues to designate the number of carbons in the carbocyclic ring system. The term “cycloalkyl” also includes bicyclic or polycyclic fused, bridged, or spiro ring systems that contain from 5 to 14 carbon atoms and zero heteroatoms in the non-aromatic ring system. Representative examples of “cycloalkyl” include, but are not limited to,

[0104] The term “bicycle” refers to a ring system wherein two rings are fused together, and each ring is independently selected from carbocycle, heterocycle, aryl, and heteroaryl. Non-limiting examples of bicycle groups include:

[0105] The terms “amine” or “amino” as used herein are represented by the formula — NR1R2, where R1and R2can each be substitution groups as described herein, such as hydrogen, an alkyl, halogenated alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl, or heterocycloalkenyl group described above. “Amido” is — C(O)NR1R2.

[0106] The term “anhydride” as used herein is represented by the formula Z1C(O)OC(O)Z2, where Z1and Z2, independently, can be an alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl, or heterocycloalkenyl group described above.

[0107] The term “cyclic anhydride,” as used herein, is represented by the formula:

[0108] where Z1can be an alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl, or heterocycloalkenyl group described above.

[0109] The term “azide,” as used herein, is represented by the formula -N=N=N.

[0110] The term “aldehyde,” as used herein, is represented by the formula -C(O)H.Throughout this specification, “C(O)” or “CO” is a shorthand notation for C=O, which is also referred to herein as a “carbonyl.”

[0111] The term “carboxylic acid,” as used herein, is represented by the formula - C(O)OH. A “carboxylate” or “carboxyl” group, as used herein, is represented by the formula -C(O)O_

[0112] The term “ester” as used herein is represented by the formula -OC(O)R1or - C(O)OR1, where R1can be an alkyl, halogenated alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl, or heterocycloalkenyl group described above.

[0113] The term “ether” as used herein is represented by the formula R1OR2, where R1and R2can be, independently, an alkyl, halogenated alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl, or heterocycloalkenyl group described above.

[0114] The term “epoxy” or “epoxide” as used herein refers to a cyclic ether with a three-atom ring and can be represented by the formula:

[0115] where Z1, Z2, Z3, and Z4can be, independently, H, an alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl, or heterocycloalkenyl group described above.

[0116] The term “ketone” as used herein is represented by the formula R1C(O)R2, where R1and R2can be, independently, an alkyl, halogenated alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl, or heterocycloalkenyl group described above.

[0117] The term “halide,” or “halogen,” or “halo,” as used herein, refers to fluorine, chlorine, bromine, and iodine.

[0118] The term “hydroxyl,” as used herein, is represented by the formula -OH.

[0119] The term “nitro,” as used herein, is represented by the formula -NO2.

[0120] The term “phosphonyl” is used herein to refer to the phospho-oxo group represented by the formula -P(O)(OZ1)2, where Z1can be hydrogen, an alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl, or heterocycloalkenyl group described above.

[0121] The term “silyl” as used herein is represented by the formula -SiZ1Z2Z3, where Z1, Z2, and Z3can be, independently, hydrogen, alkyl, alkoxy, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl, or heterocycloalkenyl group described above.

[0122] The term “sulfonyl” or “sulfone” is used herein to refer to the sulfo-oxo group represented by the formula -S(O)2Z1, where Z1can be hydrogen, an alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl, or heterocycloalkenyl group described above.

[0123] The term “sulfide,” as used herein, comprises the formula -S-.

[0124] As used herein, the term “thio” refers to a group of formulas -SH.

[0125] As used herein, the term “Cn-Cm alkylthio” refers to a group of formula -S- alkyl, wherein the alkyl group has n to m carbon atoms. In various aspects, the alkyl group has 1 to 6, 1 to 4, or 1 to 3 carbon atoms.

[0126] As used herein, the term “Cn-Cm alkylsulfonyl” refers to a group of formula - S(O)-alkyl, wherein the alkyl group has n to m carbon atoms. In various aspects, the alkyl group has 1 to 6, 1 to 4, or 1 to 3 carbon atoms.

[0127] As used herein, the term “Cn-Cm alkylsulfonyl” refers to a group of formula - S(O)2-alkyl, wherein the alkyl group has n to m carbon atoms. In various aspects, the alkyl group has 1 to 6, 1 to 4, or 1 to 3 carbon atoms.

[0128] As used herein, the term “carbamyl” refers to a group of formula -C(O)NH2.

[0129] As used herein, the term “carbonyl,” employed alone or in combination with other terms, refers to a -C(=O)- group, which may also be written as C(O).

[0130] As used herein, the term “carboxy” refers to a group of formula -C(O)OH.

[0131] As used herein, “halogen” refers to F, Cl, Br, or I.

[0132] The term “sulfonylamino” or “sulfonamide,” as used herein, is represented by the formula -S(O)2NH-.

[0133] “R1,” “R2,” “R3,” “Rn,” etc., where n is some integer, as used herein, can independently possess one or more of the groups listed above. For example, if R1is a straight chain alkyl group, one of the hydrogen atoms of the alkyl group can optionally be substituted with a hydroxyl group, an alkoxy group, an amine group, an alkyl group, a halide, and the like. Depending upon the groups that are selected, a first group can be incorporated within the second group, or alternatively, the first group can be pendant (i.e., attached) to the second group. For example, with the phrase “an alkyl group comprising an amino group,” the amino group can be incorporated within the backbone of the alkyl group. Alternatively, the amino group can be attached to the backbone of the alkyl group. The nature of the group(s) that is (are) selected will determine if the first group is embedded or attached to the second group.

[0134] Unless stated contrary, a formula with chemical bonds shown only as solid lines and not as wedges or dashed lines contemplates each possible stereoisomer or a mixture of stereoisomer (e.g., each enantiomer, each diastereomer, each meso compound, a racemic mixture, or scalemic mixture).

[0135] “Phase,” as used herein, generally refers to a region of a material having a substantially uniform composition, which is a distinct and physically separate portion of a heterogeneous system. The term “phase” does not imply that the material making up a phase is a chemically pure substance but merely that the chemical and / or physical properties of the material making up the phase are essentially uniform throughout the material and that these chemical and / or physical properties differ significantly from the chemical and / or physical properties of another phase within the material. Examples of physical properties include density, thickness, aspect ratio, specific surface area, porosity, dimensionality, stretchability, modulus, and ionic conductivity. Examples of chemical properties include chemical composition.

[0136] The term “olefinically unsaturated group” or “ethylenically unsaturated group” is employed herein in a broad sense and is intended to encompass any groups containing a carbon-carbon double-bonded group (>C=C< group). Exemplary ethylenically unsaturated groups include but are not limited to (meth)acrylate, (meth)acrylamide, (meth)acryloyl, allyl, vinyl, styrenyl, or other >C=C< containing groups.

[0137] “Polymer” means a material formed by polymerizing one or more monomers and / or one or more oligomers.

[0138] The term “(co)polymer” includes homopolymers, copolymers, or mixtures thereof.

[0139] The term “(meth)acryl...” includes “acryl...,” “methacryl...,” or mixtures thereof.

[0140] The term prepolymer is used herein to refer to a polymer that has reactive groups that are available for bond-forming reactions that will crosslink (intermolecular and / or intramolecular crosslink). It is not meant to imply that the prepolymer is not yet a polymer (e.g., a monomer or polymer precursor). Rather, a “prepolymer” refers to a starting polymer that contains multiple crosslinkable groups and can be cured (e.g., crosslinked) to obtain a crosslinked polymer having a molecular weight higher than the starting polymer.

[0141] “Molecular weight” of a polymeric material (including monomeric or macromonomeric materials), as used herein, refers to the number-average molecularweight as measured by1H NMR spectroscopy unless otherwise specifically noted or unless testing conditions indicate otherwise.

[0142] While aspects of the present invention can be described and claimed in a particular statutory class, such as the system statutory class, this is for convenience only and one of ordinary skill in the art will understand that each aspect of the present invention can be described and claimed in any statutory class. Unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that an order be inferred in any respect. This holds for any possible nonexpress basis for interpretation, including matters of logic with respect to the arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification.

[0143] The present invention may be understood more readily by reference to the following detailed description of various aspects of the invention and the examples included therein and to the Figures and their previous and following description.ELECTROLYTES AND BATTERIES

[0144] The current disclosure is directed to electrolyte solutions that allow fast charging in Ll-based batteries. In still further aspects, the disclosed herein electrolytes can be used with the common in the art cathodes, anodes, and / or separators as disclosed in detail below.

[0145] In one aspect disclosed herein is an electrolyte solution comprising: (a) about 5 wt % to about 60 wt % of a fluorinated ester; (b) greater than 0 wt % to less than 100 wt % of at least one solvent selected from fluoroethylene carbonate, difluoroethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl (2,2,2-trifluoroethyl) carbonate, propylene carbonate, trifluoropropylene carbonate, butylene carbonate, methyl acetate (MA), ethyl acetate (EA), methyl propanoate (MP); (c) at least one salt; wherein the wt % is calculated based on a total weight of a) and b); and wherein the electrolyte solution is substantially free of ethylene carbonate (EC).

[0146] In still further aspects, the fluorinated ester can be present in an amount of about 5 wt % to about 60 wt %, including exemplary values of about 7.5 wt %, about 10 wt %, about 12.5 wt %, about 15 wt %, about 17.5 wt %, about 20 wt %, about22.5 wt %, about 25 wt %, about 27.5 wt %, about 30 wt %, about 32.5 wt %, about 35 wt %, about 37.5 wt %, about 40 wt %, about 42.5 wt %, about 45 wt %, about47.5 wt %, about 50 wt %, about 52.5 wt %, about 55 wt %, and about 57.5 wt %. In yet still further aspects, the fluorinated ester can be present in any amount that falls within any two foregoing values or forms any range within the broadest disclosed range or between any mentioned values. For example, the fluorinated ester can be present in the electrolyte solution in an amount of about 5 wt % to about 40 wt % or about 5.5 wt %to about 50 wt % or about 5.5 wt %to about 58 wt % or about 10 wt % to about 45 wt %, or about 10 wt % to about 30 wt % or about 12.7 % to about 25 wt %, or about 10 wt % to about 20 wt % or about 7 wt % to about 15 wt %, or about 5 wt % to about 25 wt %, or about 10 wt % to about 35 wt %, or about 15 wt % to about 20 wt %, and so on. It is further understood that the ranges can also be formed within the range, for example, if a range of about 5 wt % to about 60 wt % is disclosed, this range also includes about 5 wt % to about 50 wt %, or about 5 wt % to about 40 wt % or about 7 wt % to about 35 wt %, or about 7 wt % to about 25 wt %, or about 10 wt % to about 35 wt %, or about 15 wt % to about 20 wt %, and so on.

[0147] In yet still further aspects, the fluorinated ester can be present in an amount of at least about 5 wt %, at least about 7 wt %, at least about 10 wt %, at least about 12 wt %, at least about 15 wt %, at least about 17 wt %, at least about 20 wt %, at least about 22 wt %, at least about 25 wt %, at least about 27 wt %, at least about 30 wt %, at least about 35 wt %, at least about 37 wt %, at least about 40 wt %, at least about 45 wt %, at least about 47 wt %, at least about 50 wt %, at least about 55 wt %, or at least about 60 wt %. In yet still further aspects, the fluorinated ester can be present in an amount not greater than about 60 wt %, not greater than about 57 wt %, not greater than about 55 wt %, not greater than about 52 wt %, not greater than about 50 wt %, not greater than about 47 wt %, not greater than about 45 wt %, not greater than about 42 wt %, not greater than about 40 wt %, not greater than about 37 wt %, not greater than about 35 wt %, not greater than about 32 wt %, not greater than about 30 wt %, not greater than about 27 wt %, not greater than about 25 wt %, not greater than about 22 wt %, not greater than about 20 wt %, not greater thanabout 17 wt %, not greater than about 15 wt %, not greater than about 12 wt %, not greater than about 10 wt %, or not greater than about 7 wt %.

[0148] In still further aspects, the electrolyte solution can comprise a solvent selected from fluoroethylene carbonate, difluoroethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl (2,2,2-trifluoroethyl) carbonate, propylene carbonate, trifluoropropylene carbonate, butylene carbonate, methyl acetate (MA), ethyl acetate (EA), methyl propanoate (MP) present in an about greater than 0 wt % to less than 100 wt %, including exemplary values of about 0.01 wt %, about 0.05 wt %, about 0.1 wt %, about 0.5 wt %, about 1 wt %, about 5 wt %, about 10 wt %, about 20 wt %, about 30 wt %, about 40 wt %, about 50 wt %, about 60 wt %, about 70 wt %, about 80 wt %, and about 90 wt %.

[0149] In yet still further aspects, the disclosed above solvent can be present in any amount that falls within any two foregoing values or forms any range within the broadest disclosed range or between any mentioned values. For example, the disclosed above solvent can be present in the electrolyte solution in an amount of about 5 wt % to about 90 wt %, about 10 wt % to about 80 wt %, or about 20 wt % to about 80 wt % or about 20 wt % to about 60 wt % or about 25 wt % to about 55 wt % and so on. It is further understood that the ranges can also be formed within the range, for example, if a range of about 20 wt % to about 60 wt % is disclosed, this range also includes about 22 wt % to about 58 wt %, or about 25 wt % to about 55 wt %, and so on.

[0150] In yet still further aspects, the disclosed above solvent can be present in an amount of at least about 1 wt %, at least about 5 wt %, at least about 10 wt %, at least about 15 wt %, at least about 20 wt %, at least about 25 wt %, at least about 30 wt %, at least about 35 wt %, at least about 40 wt %, at least about 45 wt %, at least about 50 wt %, at least about 55 wt %, at least about 60 wt %, at least about 65 wt %, at least about 70 wt %, at least about 75 wt %, at least about 80 wt %, at least about 85 wt %, and at least about 90 wt %. In yet still further aspects, the disclosed above solvent can be present in an amount not greater than about 95 wt %, not greater than about 90 wt %, not greater than about 80 wt %, not greater than about 75 wt %, not greater than about 70 wt %, not greater than about 65 wt %, not greater than about 60 wt %, not greater than about 55 wt %, not greater than about 50 wt %, not greater than about 45 wt %, not greater than about 40 wt %, not greater thanabout 35 wt %, not greater than about 30 wt %, not greater than about 25 wt %, not greater than about 20 wt %, not greater than about 15 wt %, not greater than about 10 wt %, not greater than about 5 wt %.

[0151] In still further aspects, the electrolyte solution can comprise two or more solvents. In still further aspects, if two or more solvents are present in the electrolyte solution, a first of the two or more solvents is fluoroethylene carbonate. Yet, in other aspects, a second of the two or more solvents are selected from ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, and butylene carbonate, 2,3- butylene carbonate, i-butylene carbonate. In still further aspects, the second solvent can be selected from the disclosed group, while in other aspects, the second solvent can comprise propyl acetate, butyl acetate, ethyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, ethyl formate, methyl formate, n-propyl formate, i-propyl formate, n-butyl formate, i-butyl formate, acetonitrile, propionitrile, n- butyronitrile, i-butyronitrile, 3-methoxypropionitrile, 3-ethoxypropionitrile, (2,2,2- trifluoro) ethoxypropionitrile, dimethoxyethane, fluorosulfonyl isocyanate, 2- trifluoromethyl-3-methoxyperfluoropentane, 2-(trifluoro-2-fluoro-3-difluor-oproxy)-3- difluoro-4-fluoro-5-trifluoropentane.

[0152] In yet other aspects, the electrolyte solution is substantially free of ethylene carbonate. In still further aspects, the electrolyte solution is free of ethylene carbonate.

[0153] In still further aspects, if two solvents are present, they can be present in any ratio. In certain aspects, the first solvent is present in an amount of about 10 wt % to about 40 wt %, including exemplary values of about 12 wt %, about 15 wt %, about 17 wt %, about 20 wt %, about 22 wt %, about 25 wt %, about 27 wt %, about 30 wt %, about 32 wt %, about 35 wt %, and about 37 wt %. In yet still further aspects, the first solvent can be present in any amount that falls within any two foregoing values or forms any range within the broadest disclosed range or between any mentioned values. For example, the first solvent can be present in the electrolyte solution in an amount of about 10 wt % to about 35 wt % or about 15 wt % to about 40 wt %, or about 20 wt % to about 30 wt % or about 12 wt % to about 38 wt % or about 15 wt % to about 25 wt % and so on. It is further understood that the ranges can also be formed within the range, for example, if a range of about 10 wt % to about 35 wt % is disclosed, this range also includes about 10 wt % to about 30 wt %, or about 10 wt %to about 25 wt % or about 15 wt % to about 30 wt %, or about 15 wt % to about 20 wt %, and so on.

[0154] In yet still further aspects, the first solvent can be present in an amount of at least about 10 wt %, at least about 12 wt %, at least about 15 wt %, at least about 17 wt %, at least about 20 wt %, at least about 22 wt %, at least about 25 wt %, at least about 27 wt %, at least about 30 wt %, at least about 32 wt %, at least about 35 wt %, or at least about 37 wt %. In yet still further aspects, the first solvent can be present in an amount not greater than about 40 wt %, not greater than about 37 wt %, not greater than about 35 wt %, not greater than about 32 wt %, not greater than about 30 wt %, not greater than about 27 wt %, not greater than about 25 wt %, not greater than about 22 wt %, not greater than about 20 wt %, not greater than about 17 wt %, not greater than about 15 wt %, not greater than about 12 wt %, or not greater than about 10 wt %.

[0155] In still further aspects, the second solvent is present in an amount of about 20 wt % to about 70 wt %, including exemplary values of about 25 wt %, about 30 wt %, about 35 wt %, about 40 wt %, about 45 wt %, about 50 wt %, about 55 wt %, about 60 wt %, and about 65 wt %. In yet still further aspects, the second solvent can be present in any amount that falls within any two foregoing values or forms any range within the broadest disclosed range or between any mentioned values. For example, the second solvent can be present in the electrolyte solution in an amount of about 20 wt % to about 65 wt % or about 25 wt % to about 60 wt %, or about 25 wt % to about 55 wt % or about 30 wt % to about 70 wt % or about 25 wt % to about 70 wt % and so on. It is further understood that the ranges can also be formed within the range, for example, if a range of about 20 wt % to about 65 wt % is disclosed, this range also includes about 20 wt % to about 60 wt %, or about 20 wt % to about 55 wt % or about 25 wt % to about 60 wt %, or about 25 wt % to about 55 wt %, and so on.

[0156] In yet still further aspects, the second solvent can be present in an amount not greater than about 70 wt %, not greater than about 67 wt %, not greater than about 65 wt %, not greater than about 62 wt %, not greater than about 60 wt %, not greater than about 57 wt %, not greater than about 55 wt %, not greater than about 52 wt %, not greater than about 50 wt %, not greater than about 47 wt %, not greater than about 45 wt %, not greater than about 42 wt %, not greater than about 40 wt %, not greater than about 37 wt %, not greater than about 35 wt %, not greater thanabout 32 wt %, not greater than about 30 wt %, not greater than about 27 wt %, not greater than about 25 wt %, not greater than about 22 wt %, or not greater than about 20 wt %. In yet still further aspects, the second solvent can be present in an amount of at least about 20 wt %, at least about 22 wt %, at least about 25 wt %, at least about 27 wt %, at least about 30 wt %, at least about 32 wt %, at least about 35 wt %, at least about 37 wt %, at least about 40 wt %, at least about 42 wt %, at least about 45 wt %, at least about 47 wt %, at least about 50 wt %, at least about 52 wt %, at least about 55 wt %, at least about 57 wt %, at least about 60 wt %, at least about 62 wt %, at least about 65 wt % or at least about 67 wt %.

[0157] In still further aspects, the fluorinated ester present in the electrolyte solution o can have a general structure of formula I(I).

[0158] In some aspects, R1and R2are independently selected from C1-C3 alkyl or C1-C3 fluoroalkyl having two or more fluoro groups; wherein at least one of R1and R2is C1-C3 fluoroalkyl having two or more fluoro groups. In still further aspects, an alkyl group can be linear, or it can be branched.

[0159] In still further aspects, the fluorinated ester can be a fluorinated ester of a carboxylic acid. In still further aspects, the fluorinated ester can comprise: o

[0160] F3C OCH3 or methyl trifluoroacetate (MTFA), o

[0161] or ethyl trifluoroacetate (ETFA), o

[0162] or methyl 3,3,3-trifluoropropionate (MTFP), o

[0163] H3C O / CF3 or 2,2, 2-trifluoroethyl acetate (TFEA), o

[0164] or 2,2, 2-trifluoroethyl propionate (TFEP), oA

[0165] F2HC OCH3 or methyl difluoroacetate (MDFA),

[0166] or ethyl difluoroacetate (EDFA),

[0167] F or methyl 2,3,3, 3-tetrafluoro propionate (MTFP),

[0168] F or methyl pentafluoropropionate (MPFP), o

[0169] or2,2,2-trifluoroethyl butyrate (TFEB), o

[0170] or trifluoroethyl trifluoroacetate (TFETFA) or any combination thereof.

[0171] It is understood, however, that also disclosed are aspects where the number of carbon atoms in R1or R2can be greater than 3, for example, 4, 5, 6, 7, 8, 9, or 10.

[0172] In still further aspects, it is understood that two or more fluorinated esters can be present in the electrolyte solution.

[0173] In still further aspects, the electrolyte solution can comprise methyl trifluoroacetate / fluoroethylene carbonate / dimethyl carbonate.

[0174] In yet still further aspects, the at least one salt present in the electrolyte solution can comprise any salts usually used in lithium batteries. In still further aspects, the at least one salt present in the electrolyte solution can comprise lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium bis(oxalato)borate (LiBOB), LiPF6, LiAsF6, LiBF4, LiCF3SO3, LiCIO4, lithium difluoro oxalato borate anion (LiDFOB), lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide (LiTDI), 1 ,3,2- dioxathiolane-2,2-dioxide (DTD), 4-methyl-1 ,3,2-dioxathiolane-2,2-dioxide (MDTD), lithium difluorophosphate (LiPO2F2), tris(trimethylsilyl) phosphite (TMSPi), triethyl phosphite (TEPi), tris(trimethylsilyl) phosphate (TMSPa), trimethyl boroxine (TMB), triethyl borate (TEB), p-toluenesulfonyl isocyanate (PTSI), [4,4’-bi(1 ,3,2- dioxathiolane)]2,2’-dioxide(BDTD), diphenyldimethoxysilane(DPDMS), triisopropyl borate (TIB), dimethoxydimethylsilane (DODSi), succinic anhydride(SA), diethylphenylphosphonite (DEPP), allylboronic acid pinacol ester (ABAPE), tris trimethyl silyl phosphite (TTSPi), prop-1 -ene-1 ,3-sultone (PES), 1 ,3-propane sultone (PS), ethylene sulfite (ES), or any combination thereof.

[0175] In still further aspects, the at least one salt is present in an amount of about 0.3 M to about 2 M, including exemplary values of about 0.4 M, about 0.5 M, about 0.6 M, about 0.7 M, about 0.8 M, about 0.9 M, about 1 M, about 1 .1 M, about 1 .2 M, about 1 .3 M, about 1 .4 M, about 1 .5 M, about 1 .6 M, about 1 .7 M, about 1 .8 M, and about 1 .9 M. In yet still further aspects, the at least one salt can be present in any amount that falls within any two foregoing values or forms any range within the broadest disclosed range or between any mentioned values. For example, the at least one salt can be present in the electrolyte solution in an amount of about 0.3 M to about 1 .8 M or, about 0.4 M to about 1 .5 M, or about 0.3 M to about 1 .4 M or about 0.5 M to about 1 .2 M or about 1 M to about 1 .7 M and so on. It is further understood that the ranges can also be formed within the range, for example, if a range of about 0.3 M to about 1 .4 M is disclosed, this range also includes about 0.3 M to about 1 .3 M or about 0.5 M to about 1 .2 M and so on.

[0176] In yet still further aspects, the at least one salt can be present in an amount of at least about 0.3 M, at least about 0.4 M, at least about 0.5 M, at least about 0.6 M, at least about 0.7 M, at least about 0.8 M, at least about 0.9 M, at least about 1 .0M, at least about 1 .1 M, at least about 1 .2 M, at least about 1 .3 M, at least about 1 .4M, at least about 1 .5 M, at least about 1 .6 M, at least about 1 .7 M, at least about 1 .8M, or at least about 1 .9 M. In yet still further aspects, the at least one salt can be present in an amount not greater than about 2 M, not greater than about 1 .9 M, not greater than about 1 .8 M, not greater than about 1 .7 M, not greater than about 1 .6 M, not greater than about 1 .5 M, not greater than about 1 .4 M, not greater than about 1 .3 M, not greater than about 1 .2 M, not greater than about 1 .1 M, not greater than about 1 .0 M, not greater than about 0.9 M, not greater than about 0.8 M, not greater than about 0.7 M, not greater than about 0.6 M, not greater than about 0.5 M, or not greater than about 0.4 M.

[0177] In still further aspects, a concentration of the at least one salt can be presented in wt % of the electrolyte composition. For example and without limitations, in such aspects, the at least one salt can be present in an amount greater than 0 wt % to about 50 wt %, including exemplary values of about 0.01 wt %, about0.5 wt %, about 1 wt %, about 1 .5 wt %, about 2 wt %, about 3 wt %, about 4 wt %, about 5 wt %, about 10 wt %, about 15 wt %, about 20 wt %, about 25 wt %, about 30 wt %, about 35 wt %, about 40 wt %, and about 45 wt %. In yet still further aspects, the at least one salt can be present in any amount that falls within the any two foregoing values or forms any range within the broadest disclosed range or between any mentioned values. For example, the at least one salt can be present in the electrolyte solution in an amount of about 0.1 wt % to about 2 wt % or about 0.1 wt % to about 1 .5 wt %, or about 0.5 wt % to about 1 .5 wt % or about 1 wt % to about 5 wt % or about 1 wt % to about 10 wt % and so on. It is further understood that the ranges can also be formed within the range, for example, if a range of about 0.1 wt % to about 10 wt % is disclosed, this range also includes about 0.1 wt % to about 1 wt % or about 0.5 wt % to about 1 .5 wt %, or about 0.8 wt % to about 2.7 wt %, about 0.8 wt % to about 7 wt %, and so on.

[0178] In still further aspects, the at least one salt can comprise LiPFe. Yet, in other aspects, the at least one salt further comprises LiBOB and / or LiDFOB. In yet still further aspects, LiBOB and / or LiDFOB are present in amounts greater than 0 wt % to about 5 wt %, including exemplary values of about 0.01 wt %, about 0.5 wt %, about 1 wt %, about 1 .5 wt %, about 2 wt %, about 3 wt %, and about 4 wt %. In still further aspects, LiBOB and / or LiDFOB can be present in an amount of about 0.01 wt % to about 2 wt % or about 0.05 wt % to about 3 wt %, or about 0.1 wt % to about 2.5 wt %, or about 0.5 wt % to about 1 .5 wt %, and so on.

[0179] In still further aspects, the resulting electrolyte solution can exhibit a conductivity greater than about 9 mS / cm to about 25 mS / cm, including exemplary values of about 10 mS / cm, about 11 mS / cm, about 12 mS / cm, about 13 mS / cm, about 14 mS / cm, about 15 mS / cm, about 16 mS / cm, about 17 mS / cm, about 18 mS / cm, and about 19 mS / cm. In yet still further aspects, the electrolyte solution can exhibit a conductivity having any amount that falls within the any two foregoing values or forms any range within the broadest disclosed range or between any mentioned values. For example, the conductivity of the electrolyte solution can be about 9 mS / cm to about 19 mS / cm, or about 9 mS / cm to about 18 mS / cm or about 9 mS / cm to about 17 mS / cm or about 9 mS / cm to about 16 mS / cm, or about 9 mS / cm to about 15 mS / cm, or about 9 mS / cm to about 14 mS / cm, or about 9 mS / cm to about 13 mS / cm, or about 9 mS / cm to about 12 mS / cm, or about 9 mS / cm to about11 mS / cm, or about 9 mS / cm to about 10 mS / cm and so on. It is further understood that the ranges can also be formed within the range, for example, if a range of about 9 mS / cm to about 20 mS / cm is disclosed, this range also includes about 9.5 mS / cm to about 15 mS / cm, or about 10.5 mS / cm to about 13 mS / cm, and so on.

[0180] In yet still further aspects, the conductivity can be at least about 9 mS / cm, at least about 10 mS / cm, at least about 11 mS / cm, at least about 12 mS / cm, at least about 13 mS / cm, at least about 14 mS / cm, at least about 15 mS / c, at least about 16 mS / cm, at least about 17 mS / cm, at least about 18 mS / cm, at least about 19 mS / cm or at least about 20 mS / cm. It is understood that in some aspects, the conductivity can be greater than about 20 mS / cm. For example, it can be about 25 mS / cm to about 100 mS / cm, or about 25 mS / cm to about 90 mS / cm, about 25 mS / cm to about 80 mS / cm, about 25 mS / cm to about 70 mS / cm, about 25 mS / cm to about 60 mS / cm, about 25 mS / cm to about 50 mS / cm, about 25 mS / cm to about 40 mS / cm, or about 25 mS / cm to about 30 mS / cm.

[0181] In still further aspects, the electrolyte solution disclosed herein, when is used in an electrochemical cell, is capable of forming an inorganic-rich interphase layer on at least one electrochemically active surface during an operation of the electrochemical cell. In still further aspects, the inorganic-rich interface layer is substantially uniform and substantially compact. It is understood that the term “compact,” as used herein, describes the interface layer as substantially resisting the movement of the electrolyte through this layer to the at least one electrochemical active surface. In still further aspects, the inorganic-rich interface layer formed with the described herein electrolyte is substantially insulating to electrons tunneling while conducive to the ions. In still further aspects, the inorganic-rich interface layer comprises a degradation product of at least a portion of at least a component of the electrolyte solution.

[0182] In still further aspects, the electrolyte solution disclosed herein is substantially free of electrochemical decomposition up to at least about 4.2 V when measured against a Li-metal anode. In some other aspects, the electrochemical decomposition voltage can occur about 4.40 V, about 4.50 V, about 4.60 V, about 4.70 V, about 4.80 V, about 4.90 V, about 5.00 V, or about 5.10 V when measured against Li-metal anode.

[0183] In still further aspects, the described herein electrolyte solution, when used in a rechargeable battery, supports the rechargeable battery charging up to about 0.01 C, about 0.1 C, about 0.5C, about 1 C, about 2C, about 3 C, and up to about 4C rate for at least about 500, at least about 600, at least about 700, at least about 800, at least about 900, at least about 1000, at least about 1500, at least about 2000 or even at least about 5000 cycles at a deep charge-discharge conditions. As disclosed above, the deep charge-discharge conditions correlate to 100% and 0% of SOC, respectively.

[0184] In still further aspects, the electrolyte disclosed herein supports the rechargeable battery charging at least for about 0.01 C, at least for about 0.1 C, at least for about 0.5C, at least for about 1 C, at least for about 2C, at least for about 3 C, or at least for about 4C rate. Yet in other aspects, such charging is supported for at least about 500, at least about 600, at least about 700, at least about 800, at least about 900, at least about 1000, at least about 1500, at least about 2000 or even at least about 5000 cycles at a deep charge-discharge conditions.

[0185] In still further aspects, wherein the electrolyte solution is substantially flame resistant.

[0186] Also disclosed herein are batteries comprising the described above electrolyte solutions. In some aspects, disclosed is a secondary battery comprising: a first electroactive surface configured to behave as an anode; a second electroactive surface configured to behave as a cathode; and any of the disclosed herein electrolyte solutions.

[0187] In still further aspects, any known in the art anodes can be used. In certain exemplary and unlimiting aspects, the first electroactive surface can comprise carbon, silicon, tin, antimony, Li, Na, K, Zn, Ni, Cu, Al, silicon, silicon oxides, Mg, Li alloys, Li intermetallic, or Li compounds.

[0188] In still further aspects, the first electrochemically active surface is an anode surface or a current collector surface configured to behave as an anode during a platting step. In certain aspects, such a battery configuration can be referred to as “anode-free”. In such aspects, the anode or the current collector configured to behave as an anode during a plating step comprises carbon, silicon, tin, antimony, Li, Na, K, Zn, Ni, Cu, Al, silicon, silicon oxides, Mg, Li alloys, Li intermetallics, Licompounds, Na alloys, Na intermetallics, Na compounds, K alloys, K intermetallics, K compounds or any combination thereof.

[0189] In still further aspects, the anode can comprise an intercalation material or conversion compound that can be deposited onto a substrate (e.g., a current collector) or can be provided as a free-standing film, typically including one or more binders and / or conductive additives. Suitable binders include, but are not limited to, polyvinyl alcohol, polyvinyl chloride, polyvinyl fluoride, ethylene oxide polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, epoxy resin, nylon, and the like. Suitable conductive additives include, but are not limited to, carbon black, acetylene black, Ketjen black, carbon fibers (e.g., vapor-grown carbon fiber), metal powders or fibers (e.g., Cu, Ni, and Al), and conductive polymers (e.g., polyphenylene derivatives). In certain aspects, anode materials can include but are not limited to MoeSs, TiC , V2O5, Li4MnsOi2, Li4TisOi2, C / S composites, graphite / silicon composites, graphite, silicon, and polyacrylonitrile (PAN)-sulfur composites, NaTi2(PO4)3, TiS2, CuS, FeS2, NiCo204, Cu2Se, and Lio.5Nao.5Ti2(P04)3. In certain aspects, the electrochemical cells having the disclosed herein electrolyte can comprise a lithium metal anode, a sodium metal anode, a potassium metal anode, a graphite / silicon composite anode, a graphite anode, or a silicon anode or any other alloying anode.

[0190] In still further aspects, the battery can further comprise a solid-electrolyte interphase (SEI) (or sometimes referred to as anode-electrolyte interphase) layer disposed on a first electroactive surface and having a thickness of about 10 to about 60 nm, including exemplary values of about 12 nm, about 15 nm, about 17 nm, about20 nm, about 22 nm, about 25 nm, about 27 nm, about 30 nm, about 32 nm, about35 nm, about 37 nm, about 40 nm, about 42 nm, about 45 nm, about 47 nm, about50 nm, about 52 nm, about 55 nm, and about 57 nm. In yet still further aspects, theSEI can have any thickness that falls within the any two foregoing values or forms any range within the broadest disclosed range or between any mentioned values. For example, the thickness can be about 10 nm to about 55 nm or about 10 nm to about 50 nm, or about 10 nm to about 40 nm or about 10 nm to about 30 nm or about 10 nm to about 20 nm, or about 10 nm to about 15 nm, or about 20 nm to about 60 nm, or about 30 nm to about 60 nm, and so on. It is further understood thatthe ranges can also be formed within the range, for example, if a range of about 10 nm to about 40 nm is disclosed, this range also includes about 15 nm to about 35 nm or about 18 nm to about 28 nm, and so on.

[0191] In still further aspects, the composition of the SEI would be determined by the specific anode and the specific composition of the electrolyte solution. However, it is understood that the SEI composition of the disclosed batteries utilizing the disclosed electrolytes and anodes can comprise, for example, and without limitations, any of the following components: LiPaObFc, LiF, LiH, U2O, U2CO3, RxOLi, lithium ethylene mono-carbonate, lithium ethylene decarbonate, transition metal deposits, metallic Li, and any combination thereof. It is understood that Rxwill represent a moiety present in the electrolyte. In such aspects, a, b, and c are stoichiometric constants depending on the specific reaction products.

[0192] In still further aspects, the second electroactive surface can comprise a cathode-electrolyte interphase (CEI) layer having a thickness of about 10 to about 80 nm, including exemplary values of about 12 nm, about 15 nm, about 17 nm, about 20 nm, about 22 nm, about 25 nm, about 27 nm, about 30 nm, about 32 nm, about 35 nm, about 37 nm, about 40 nm, about 42 nm, about 45 nm, about 47 nm, about 50 nm, about 52 nm, about 55 nm, about 57 nm, about 60 nm, about 62 nm, about 65 nm, about 67 nm, about 70 nm, about 72 nm, about 75 nm, and about 77 nm. In yet still further aspects, the CEI can have any thickness that falls within the any two foregoing values or forms any range within the broadest disclosed range or between any mentioned values. For example, the thickness can be about 10 nm to about 75 nm or about 10 nm to about 60 nm, or about 10 nm to about 50 nm or about 10 nm to about 40 nm or about 10 nm to about 30 nm, or about 10 nm to about 20 nm, or about 20 nm to about 80 nm, or about 30 nm to about 80 nm, and so on. It is further understood that the ranges can also be formed within the range, for example, if a range of about 10 nm to about 60 nm is disclosed, this range also includes about 15 nm to about 55 nm or about 18 nm to about 43 nm, and so on.

[0193] In still further aspects, the second electroactive surface comprises a metal or a composite material. In such exemplary and unlimiting aspects, the second electroactive surface comprises layered oxide cathodes, vanadium-based cathode, sulfur-based cathode, manganese-based cathode, rocksalt cathode, disordered rocksalt cathode, lithium-rich cathode, NMC (nickel-manganese-cobalt oxide)cathode, NCA (nickel-cobalt-aluminum oxide) cathode, NFM (nickel-iron-manganese oxide) cathode, LCO (lithium-cobalt oxide) cathode, LFP (lithium iron phosphate) cathode, fluoride-based cathode, sulfur selenium cathode, selenium cathode, tellurium cathode, spinels cathode, olivines cathode, or any combination thereof.

[0194] In still further aspects, the second electrochemical surface (cathode) can comprise Lii+wNixMnyCoz02 (x+y+z+w=1 , 0<w<0.25), LiNixMnyCoz02 (x+y+z=1 ), LiNi0.8Co0.15AI0.05 O2, UC0O2, LiNio.5Mm.5O4 spinel, LiMn2O4, LiFePO4, Li4 xMxTi50i2 (M=Mg, Al, Ba, Sr, or Ta; 0<x<1 ), MnO2, V2O5, V60i3, LiV3O8, LiMc1XMC21- XPO4(MC1or MC2=Fe, Mn, Ni, Co, Cr, or Ti; 0<x<1 ), Li3V2-xM1X(PO4)3(M1=Cr, Co, Fe, Mg, Y, Ti, Nb, or Ce; 0<x<1 ), UVPO4F, LiMc1XMC2i-xO2 ((Mc1 and MC2independently are Fe, Mn, Ni, Co, Cr, Ti, Mg, or Al; 0<x<1 ), LiMc1XMC2yMC3i-x-yO2((Mc1, MC2, and MC3independently are Fe, Mn, Ni, Co, Cr, Ti, Mg, or Al; 0<x<1 ; 0<y<1 ), LiMm-yXyO4 (X=Cr, Al, or Fe, 0<y<1 ), LiNio.5-yXyMm.504 (X=Fe, Cr, Zn, Al, Mg, Ga, V, or Cu; 0<y<0.5), xLi2MnO3.(1 -x)LiMc1yMC2ZMC3i-y-zO2 (Mc1, MC2, and MC3independently are Mn, Ni, Co, Cr, Fe, or mixture thereof; x=0.3-0.5; y<0.5; z<0.5),Li2M2SiO4(M2=Mn, Fe, or Co), Li2M2SO4 (M2=Mn, Fe, or Co), LiM2SO4F (M2=Fe, Mn, or Co), Li2-x(Fei-yMny)P2O? (0^y^1 ), Na2 / 3Fei / 2Mni / 2O2, NaNio.sFeo.4Mno.sO2, Nao.76Mno.5Nio.sFeo.1Mgo.1O2, NaNii / 4Nai / eMn2 / i2Ti4 / i2Sni / i2O2,LiFePO4Cr3O8, CrsOs, NaFePO4, Na2FePO4F, Na2FeP2O7, Na3V2(PO4)3, Na3V2(PO4)2F3, NaVPCMF, NaVPOPOF, Nai.sVOPC Fo.s, NaCo204, Na2Ti3O7, and NaxMOs where 0.4<x<1 , and M is a transition metal or a mixture of transition metals (e.g., NaCrOs, NaCoOs, NaxCoOs (0.4<x<0.9), Na2 / 3Nii / 3Mn2 / 3O2, Na2 / 3Fei / 2Mm / 2O2, Na2 / 3Nii / 6Coi / 6Mn2 / 302, NaNii / 3Fei / 3Mni / 3O2, NaNii / 3Fei / 3Coi / 302, NaNii / 2Mni / 2O2, Prussian white analogue cathodes (e.g., Na2MnFe(CN)e and Na2Fe2(CN)e), Prussian blue analogue (PBA) cathodes (Na2-xMa[Mb(CN)6]i-y.nH2O, wherein MaandMbindependently are Fe, Co, Ni, or Cu, x=0 to 0.2, y=0 to 0.2, n=1 to 10). Other sodium intercalation materials include Na4TisOi2, Fe3O4, TiOs, Sb2O4, Sb / C composite, SnSb / C composite, BiSb / C composite, and amorphous P / C composite. In an independent embodiment, the cathode is a sodium conversion compound in which sodium displaces another cation, such as FeSe, CuWO4, CuS, CuO, CuCI, or CuCI2, zirconium disulfide, cobalt (II, III) oxide, tungsten selenide, V2O5,molybdenum-vanadium oxide, stainless steel, MoeSs, Mg2Mo6Ss, M0S2, MoeSs-ySeywhere y=0, 1 , or 2, MgxS3O4 where 0<x<1 , MgCoSiCM, MgFeSiCM, MgMnSiCM, V2O5, WSe2, sulfur, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) / graphene, MnC / acetylene black, and carbyne polysulfidea carbon / sulfur composite, or an air electrode.

[0195] In still further aspects, the CEI’s composition can be dependent on the specific cathode and electrolyte solution. In some exemplary and unlimiting aspects, when the disclosed herein electrolyte solutions and cathodes are used, the CEI can comprise LiPaObFc, ROLi, ROCOOLi, RCFn, Li, MFx (where M can be Ni, Co, Mn, Al, etc., and wherein x is from 1 to 4). In such aspects, a, b, c, and n can be found by stoichiometry of the reaction products during the battery operation, and R can be a moiety present in the electrolyte solution.

[0196] In aspects where the electrochemical cell comprises the disclosed above anode materials, substantially no dendrites are formed on the anode surface or the current collector during a plating or stripping cycle.

[0197] In still further aspects, the electrochemical cells using the disclosed herein electrolytes and cathodes exhibit a surface of the cathode that is substantially free of cracks during the cell operation.

[0198] In still further aspects, the electrochemical cells described herein can comprise current collectors. In such aspects, the current collectors can be a metal or another conductive material, such as (but not limited to) nickel (Ni), copper (Cu), aluminum (Al), iron (Fe), stainless steel, or conductive carbon materials. The current collector may be a foil, a foam, or a polymer substrate coated with a conductive material.

[0199] In still further aspects, the battery disclosed herein further comprises a separator. In still further aspects, the electrochemical cell is a battery comprising two electrochemically active surfaces, an anode and a cathode. In still further aspects, the battery can comprise a separator. In such aspects, any known in the art separators that are capable of achieving the desired results can be used. For example, and without limitations, the separators can comprise glass fiber, a porous polymer film (e.g., polyethylene- or polypropylene-based material) with or without a ceramic coating, or a composite (e.g., a porous film of inorganic particles and a binder). One exemplary polymeric separator is a polyethylene (PE) membrane.Another exemplary polymeric separator is a polypropylene (PP) membrane. Another exemplary polymeric separator is a Celgard® 3501 surfactant-coated polypropylene membrane. The separator may be infused with an electrolyte, as disclosed herein.

[0200] In still further aspects, the battery exhibits a charging rate of up to about 0.01 C, about 0.1 C, about 0.5C, about 1 C, about 2C, about 3C, and up to about 4C rate for at least about 500, at least about 600, at least about 700, at least about 800, at least about 900, at least about 1000, at least about 1500, at least about 2000 or even at least about 5000 cycles at a deep charge-discharge conditions. As disclosed above, the deep charge-discharge conditions correlate to 100% and 0% of SOC, respectively. In still further aspects, the rechargeable battery disclosed herein can be charged at least for about 0.01 C, at least for about 0.1 C, at least for about 0.5C, at least for about 1 C, at least for about 2C, at least for about 3C, or at least for about 4C rate. Yet in other aspects, such charging is supported for at least about 500, at least about 600, at least about 700, at least about 800, at least about 900, at least about 1000, at least about 1500, at least about 2000 or even at least about 5000 cycles at a deep charge-discharge conditions.

[0201] In still further aspects, the fluorinated ester, the at least one solvent, and / or at least one salt present in the electrolyte solution decompose at a different rate during a battery operation. In such exemplary and unlimiting aspects, at least one of the fluorinated esters, the at least one solvent, and / or at least one salt present in the electrolyte solution decompose at greater than about 0.9 V (vs. Li / Li+) and thereby forming the disclosed herein SEI on the anode.

[0202] In still further aspects, the battery exhibits a Coulombic efficiency greater than about 98%, greater than about 98.5%, greater than about 98.9%, greater than about 99.0%, greater than about 99.2%, greater than about 99.5%, greater than about 99.9%, over at least about 500 cycles, at least about 600, at least about 700, at least about 800, at least about 900, at least about 1000, at least about 1500, at least about 2000 or even at least about 5000 cycles at a charge rate of up to about 0.01 C, up to about 0.1 C, up to about 0.5C, up to about 1 C up to about 2C, up to about 3 C, or up to about 4C rate.

[0203] In still further aspects, battery exhibits capacity retention of about 80% or greater, about 85% or greater, about 90% or greater, about 95% or greater, or about 99% or greater after at least about 2000 cycles, at least about 3000, at least about4000, at least about 5000, at least about 6000, at least about 7000, at least about 8000, at least about 2000 or even at least about 10000 cycles at 4C rate.

[0204] In still further aspects, the battery exhibits a capacity retention of at least greater than about 80 %, at least greater than about 85%, at least greater than about 90%, at least greater than about 95%, or at least greater than about 99% after at least about 100 cycles, at least about 200 cycles, at least about 300 cycles, at least about 400 cycles, at least about 500 cycles, at least about 600 cycles, at least about 700 cycles, at least about 800 cycles, at least about 900 cycles, at least about 950 cycles, at least about 1000 cycles, at least about 2000 cycles, at least about 3000, at least about 4000, at least about 5000, at least about 6000, at least about 7000, at least about 8000, at least about 2000 or even at least about 10000 cycles at 4C rate.

[0205] In still further aspects, the battery exhibits a capacity retention of at least greater than about 90 % for at least 500 cycles at a 4C rate.

[0206] In still further aspects, secondary battery is capable of operating in a temperature range from about -25 °C to about 60 °C, including exemplary values of about -22 °C, about -20 °C, about -15 °C, about -10 °C, about -5 °C, 0 °C, about 5 °C, about 10 °C, about 15 °C, about 20 °C, about 25 °C, about 30 °C, about 35 °C, about 40 °C, about 45 °C, about 50 °C, and about 55 °C. In yet still further aspects, the secondary battery can operate at any temperature that falls within the disclosed range or any range that can be formed within the broadest range or formed by any two of the disclosed values. For example, the battery can operate between about -20 °C to about 40 °C, or about -22 °C to about 55 °C, or about -15 °C to about 37 °C, or -10 °C to about 60 °C, or about 0 °C to about 40 °C, or about 0 °C to about 60 °C, or about 0 °C to about 50 °C, and so on.

[0207] In still further aspects, the secondary battery exhibits a specific capacity of about 100 mA h g-1to about 300 mA h g1, including exemplary values of about 110 mA h g-1, about 120 mA h g-1, about 130 mA h g-1, about 140 mA h g-1, about 150 mA h g-1, about 180 mA h g-1, about 190 mA h g-1, about 200 mA h g-1, about 210 mA h g1, about 220 mA h g1, about 230 mA h g1, about 240 mA h g1, about 250 mA h g1, about 260 mA h g1, about 270 mA h g1, about 280 mA h g1, and about290 mA h g1, at charge rates up to about 0.01 C, up to about 0.1 C, up to about 0.5C, up to about 1 C up to about 2C, up to about 3 C, or up to about 4C. It isunderstood that the specific capacity of the battery can have any value within any two of the disclosed values or can fall within any range formed by any two of the disclosed values. For example, the specific capacity can be about 180 mA h g-1to about 250 mA h g1, about 160 mA h g-1to about 190 mA h g-1to about 148 mA h g-1to about 195 mA h g-1at any of the disclosed above charge rates.

[0208] By way of example, the batteries of the present disclosure may be used in portable batteries, including those in hand-held and / or wearable electronic devices, such as a phone, watch, or laptop computer; in stationary electronic devices, such as a desktop or mainframe computer; in an electric tool, such as a power drill; in an electric or hybrid land, water, or air-based vehicle, such as a boat, submarine, bus, train, truck, car, motorcycle, moped, powered bicycle, airplane, drone, other flying vehicle, or toy versions thereof; for other toys; for energy storage, such as in storing electric power from wind, solar, wave, hydropower, or nuclear energy and / or in grid storage, or as a stationary power store for small-scale use, such as for a home, business, or hospital.

[0209] In addition, batteries, according to the present disclosure, may be multi-cell batteries containing at least about 10, at least about 100, at least about 500, between 10 and 10,000, between 100 and 10,000, between 1 ,000 and 10,000, between 10 and 1000, between 100 and 1 ,000, or between 500 and 1 ,000 electrochemical cells of the present disclosure. Cells in multi-cell batteries may be arranged in parallel or in series.

[0210] Also disclosed herein are the methods of making the disclosed electrolytes and electrochemical cells comprising the same.

[0211] By way of a non-limiting illustration, examples of certain aspects of the present disclosure are given below.EXAMPLES

[0212] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices, and / or methods claimed herein are made and evaluated and are intended to be purely exemplary and are not intended to limit the disclosure. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should beaccounted for. Unless indicated otherwise, parts are parts by weight, temperature is degrees C or is at ambient temperature, and pressure is at or near atmospheric.METHODS

[0213] In this work, a group of fluorinated ester-based fast-charging electrolytes (FCEs) that are composed of low-cost LiPFe salt in, for example, dimethyl carbonate (DMC), fluoroethylene carbonate (FEC), and methyl trifluoroacetate (MTFA) is shown. Based on a comprehensive electrochemical performance evaluation, it is demonstrated that the employment of MTFA, even at a low mass ratio of ~ 10 wt. %, can significantly extend the cycle life of graphite | LiNio.8Mno.1Coo.1O2 (NCM81 1 ) pouch full cells. With further compositional optimization, the cells with FCEs can deliver a capacity retention of 90% after 1 ,000 cycles at a high charge-discharge rate of 4C-2C, vastly outperforming the cells with the conventional LP57 electrolyte, where LP57 refers to 1 M LiPFe in a mixture of ethylene carbonate (EC) I ethyl methyl carbonate (EMC) in a weight ratio of 3:7, along with 2 wt. % vinylene carbonates (VC) as an additive. Based on various advanced characterizations, such as nuclear magnetic resonance (NMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary-ion mass spectrometry (ToF-SIMS), and scanning electron microscopy (SEM), the influences of MTFA on the physiochemical properties of electrolyte and electrode-electrolyte interphase (EEI) chemistry are unveiled. Finally, the safety performances of the FCEs, such as flammability and thermal stability, are also evaluated with flammability and differential scanning calorimetry tests.

[0214] Material Synthesis: Nio.8Mno.iCoo.i(OH)2 precursor was synthesized by a traditional co-precipitation method with a batch tank reactor. An aqueous salt solution was prepared by mixing NiSO4-6H2O, C0SO4 7H2O, and MnSO4-7H2O at a Ni: Mn: Co molar ratio of 0.8:0.1 :0.1 . Following that, the aqueous solution was pumped into a 10 L batch tank reactor, while simultaneously being supplemented with specific quantities of saturated NH4OH and KOH aqueous solutions. The pH value (~ 11 ) was controlled within a certain range. Temperature (~ 50 °C) and stirring rate (~ 700 rpm) were also judiciously controlled during the whole coprecipitation process. The obtained precursors were washed a couple of times with deionized water before drying overnight at 100 °C in an oven to remove the residual watercontent for further use. The LiNio.sMno.iCoo.i (NMC811 ) cathode powders were prepared by mixing the hydroxide precursors with LiOH (molar ratio of Li : (Ni + Co + Mn) = 1 .02: 1 ) and calcining at 770 °C for 15 h under a flowing O2 atmosphere.

[0215] Electrode Fabrication: he cathode electrodes were fabricated by making slurries with the mixture of active materials (NMC811 ), carbon black (Super P), and poly (vinylidene fluoride) (PVDF) (weight ratio of 0.9:0.05:0.05) in a certain amount of N-methyl-2-pyrrolidone (NMP). The resulting slurries were then cast onto an Al foil with an active material loading of ~ 2 mA h cm-2and quickly dried at 110 °C in an oven. The dried cathode electrodes were punched into 12 mm round disks and sheets with dimensions 5.6 cm x 4.3 cm for making coin and pouch full cells, respectively. Graphite anode electrodes used in this study were purchased from MTI Corp. Celgard 2500 separators were employed in both coin and pouch full cells. Pouch full cells were assembled by pairing the cathode electrode with the graphite anode electrode with a negative / positive (N / P) ratio of 1 .08 ~ 1.1.

[0216] Electrolyte Preparation: The baseline electrolyte (LP57) consists of 1 M of LiPFe dissolved in a mixture of ethylene carbonate (EC) / ethyl methyl carbonate (EMC) in a weight ratio of 3:7, along with 2 wt. % vinylene carbonates (VC) as an additive. The specific compositions of FCE0, FCE5, FCE10, FCE15, FCE20, FCE25, FCE30, FCE35 electrolytes are given in Table 1 . In the FCE electrolytes, the dimethyl carbonate: fluoroethylene carbonate (DMC: FEC) ratio was maintained constant, and the amount of DMC + FEC mixture was decreased upon adding various amounts of methyl trifluoroacetate (MTFA). FCE20-MA is composed of 1 .2 M LiPFe in FEC / DMC / methyl acetate (MA) in a weight ratio of 0.24:0.56:0.2, with the addition of 1 wt. % of lithium bis(oxalato)borate (LiBOB). FCE20-NA is identical to FCE20, with the only difference being that no additives are included. FCE20-DFOB is the same as FCE20 except by replacing the 1 wt. % LiBOB with lithium difluoro(oxalato)borate (DiFOB).

[0217] Electrochemical Evaluation: For high-voltage cycling, the coin full cells were first cycled for three times at C / 10 (1 C = 180 mA g-1) rate between 2.5 and 4.25 V, followed by charge and discharge at 1 C rate between 2.5 and 4.4 V at 23 °C. Another fast-charging protocol for coin full cells at 23 °C involves conducting three formation cycles at a C / 10 rate. Then, these cells were subjected to cycling at acharge-discharge rate of 1 C-1 C within a voltage window ranging from 2.5 V to 4.25 V. For fast-charge cycling, the pouch full cells were first cycled four times at C / 10 rate, followed by a charge-discharge rate of 4C-2C between 2.5 and 4.25 V at 30 °C for 1 ,000 cycles. Electrochemical Impedance Spectroscopy (EIS) measurements were performed on an impedance spectrometer (BioLogic, VMP3) to determine the interfacial resistances within pouch full cells. All cells were charged to 3.7 V before taking the measurements. At room temperature, a 10 mV potential perturbation was applied while sweeping the frequency from 1 MHz down to 0.01 Hz. Linear sweep voltammetry (LSV) tests were conducted with the BioLogic as well, with the sweeping voltage ranging from 2.5 to 6 V and a scanning rate of 0.05 mV / s. Cells for the LSV tests have a Li-metal chip as the anode and carbon-coated aluminum foil as the cathode.Table 1. Electrolyte formulations of the baseline electrolyte (LP57) and a series of ester-based fast-charging electrolytes (FCE)Electrolyte Electrolyte formulation codeLP57 1 .0 M LiPFe in EC-EMC (3:7 by wt.) + 2 wt.% VC (baseline) FCEXa1 .2 M of LiPFe in FEC-DMC-MTFA + 1 wt. % LiBOB, where FEC : DMC : MTFA = (5 / 16)*(100-X) : (1 1 / 16)*(100-X) : X by weightFCE20-MA 1 .2 M of LiPFe in FEC-DMC-MA (0.25: 0.55: 0.2 by weight ratio) + 1 wt. % LiBOBFCE20-DFOB 1 .2 M of LiPFe in FEC-DMC-MTFA (0.25: 0.55: 0.2 by weight ratio) + 1 wt. % DFOBFCE20-NA 1 .2 M of LiPFe in FEC-DMC-MTFA (0.25: 0.55: 0.2 by weight ratio)aFCEX is the general formula for the FCE electrolytes in which X refers to the wt. % of MTFA. For example, the wt. % of MTFA in FCE20 is 20%.

[0218] Materials Characterizations: X-ray diffraction (XRD) analysis was employed to investigate the structural characteristics of both pristine and cycled cathode materials. The analysis was carried out with a Rigaku Miniflex 600 diffractometer with Cu Ka (A = 1 .54184 A) radiation and scanning within the range of 10° to 80° at a rate of 0.5° per minute. Rietveld refinements of the XRD patterns were generatedwith the Fullprof software. The particle morphologies of the freshly calcined powders, lithiated cathode powders, and cycled electrodes were examined with an Apreo 2 C LoVac SEM. To prepare cross-sectional images of cathode samples, a Hitachi IM4000Plus ion-milling machine equipped with Ar-beam sputtering was employed.

[0219] Nuclear magnetic resonance spectroscopy (NMR) data were acquired with a Bruker Avance NEO 400 MHz NMR spectrometer. These spectra were utilized to identify the peaks corresponding to pure solvents as well as decomposition products present in the aged electrolytes after 6 months of storage and in cycled electrolytes extracted from pouch cells after 1 ,000 cycles. For sample preparation of aged and cycled electrolytes, 1 .5 mL of DMC was injected into the pouch cells and allowed to fully rinse for 15-20 minutes. Subsequently, 500 pL of the as-prepared electrolyte and 100 pL of dimethyl sulfoxide (D6-DMSO) were injected into an NMR tube and securely sealed with Parafilm. Two-dimensional (2D) diffusion-ordered spectroscopy (DOSY) of1H and19F was conducted on a Varian 600 MHz NMR spectrometer to analyze the lithium diffusion coefficient of the fresh electrolytes. To ensure the accuracy of the NMR test, a coaxial insert tube containing 100 pL of D6-DMSO was positioned within the coaxial outer tube, which was filled with 500 pL of fresh electrolyte.

[0220] X-ray photoelectron spectroscopy (XPS) analysis was conducted with a Kratos Axis Ultra DLD spectrometer, employing an Al Ka radiation source with an energy of 1486.6 eV. To prepare the cathode samples for XPS analysis, the cycled cathode electrodes were retrieved from pouch cells inside the glove box and washed with DMC three times to remove residual electrolytes attached to the surface. Subsequently, the cathode powders were scratched from the current collector and affixed onto a layer of conductive tape on the XPS sample holder bar. An air-free capsule facilitated the transfer of the sample bar into the XPS instrument for analysis. The binding energies were calibrated with respect to a reference C-C binding energy of 284.8 eV.

[0221] Time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis was carried out with a M6 spectrometer (ION-TOF GmbH). This advanced instrument offers high lateral resolution (< 50 nm), operates in an ultrahigh vacuum environment, and provides a mass resolution of > 30,000. It was employed to gain adeeper understanding of the structure, depth, and chemical compositions of electrode-electrolyte interphases (EEls). To analyze the depth profiles, a 30 keV bismuth ion (Bi+) beam was used in high current mode. Sputtering of the cycled electrodes was achieved with a 500 eV Cs+ion beam for positive mode or a 1 keV O2+ion beam for negative mode. The analysis region covered an area of 100 x 100 pm2within the 300 x 300 pm2sputtered region, with sputtering rates of approximately 0.03 nm s-1and 0.04 nm s-1for the negative and positive modes, respectively. Prior to analysis, the TOF-SIMS samples underwent the same preparation procedure as the XPS samples mentioned earlier.

[0222] Differential scanning calorimetry (DSC) measurements were conducted on a NETZSCH STA 449 thermal analysis system. The coin half cells with NMC81 1 cathode electrodes were subjected to reach a capacity of 240 mA h g-1at a C / 10 rate. Subsequently, these cells were disassembled inside a glove box, followed by cleaning and rinsing three times with DMC. After this, the dried cathode electrode materials were gathered and sealed at a torque of 2 N m within a stainless-steel crucible, along with approximately 45 wt. % electrolyte (LP57 or FCE) injected. Thermal stability tests were then performed at a controlled heating rate of 2 °C min-1, spanning the temperature range from 30 to 350 °C under a flowing Argon gas.EXAMPLE 1

[0223] The structures of the pure solvents and the prepared electrolytes were first validated with NMR. As shown in Fig. 1 A, the pure solvents in the FCEs are DMC, FEC, and MTFA, while the commercial electrolyte LP57 contains EC and ethyl methyl carbonate (EMC) with 2 wt.% vinylene carbonates (VC). The1H,13C, and19F NMR spectra presented in Fig. 1 A clearly indicate that all the solvents used in the FCEs are devoid of any impurities. These spectra help identify the corresponding peaks within the complex electrolyte system, which is a critical step for accurately assessing the performance of FCEs in the subsequent sections of the study. Table 1 , shown above, summarizes all the electrolyte compositions used in this example. The1H and19F diffusion-ordered spectroscopy (DOSY) NMR data reveal distinct diffusion coefficients for each solvent molecule within each selected electrolyte environment, including LP57, FCE0, FCE20-MA, and FCE20 (as shown in Table 2, Figs. 2A-2D, and Figs. 3A-3D). Theoretically, the diffusion coefficients in1H and19FDOSY-NMR spectra for each solvent molecule should exhibit similar trends across different electrolyte systems. Specifically, based on the1H DOSY-NMR spectra, within the LP57 electrolyte system, the diffusion rates of EC and EMC are, respectively, ~ 5.05 x 10-10m2s-1and 5.23 x 10-10m2s-1. Additionally, based on the1H DOSY-NMR spectra, in the FCE electrolyte system, MTFA exhibits the highest diffusion rate (~ 8.24 x 10-10m2s-1), followed by MA (~ 6.59 x 10-10m2s-1), DMC (~ 6.70 x 10-10m2s-1), and FEC (~ 5.60 x 10-10m2s-1).

[0224] These variations in diffusion rates highlight the differences in the mobility and interactions or coordination with lithium salts. Overall, the observation that MTFA has the highest diffusion coefficient suggests that it possesses a superior ability to facilitate a rapid transfer of lithium ions between the cathode and anode. This attribute is particularly crucial under fast charging conditions, where efficient lithium- ion kinetics play a vital role in maintaining cell performance and stability during long cycling. To evaluate the electrochemical performances of FCEs and understand the role of MTFA solvent, coin full cells were first assembled by pairing commercial graphite anode with in-house prepared LiNio.8Mno.1Coo.1O2 (NMC81 1 ) cathode and tested at a charge-discharge rate of 1 C-1 C at 23 °C. As shown in Figs. 4A and 4B, despite the removal of EC, the FCE-b electrolyte (without MTFA) functions as well as the baseline LP57 electrolyte in full cells during formation cycles at a chargedischarge rate of C / 10-C / 10, demonstrating the possibility of removing EC in battery electrolytes.

[0225] Nevertheless, upon operation under a charge-discharge rate of 1 C-1 C, the deliverable capacities of both LP57 and FCE-b cells start fading dramatically, indicating a quick loss of active lithium, possibly due to metallic Li formation on graphite anode under a high charge rate. Such a significant initial capacity loss can be greatly ameliorated with the addition of 20 wt. % of MTFA into the electrolyte (FCE20-NA). Furthermore, with the addition of electrolyte additives, such as LiBOB and LiDFOB, the cycle stability of coin full cells can be further boosted.

[0226] After 600 cycles at a moderately high charge rate of 1 C, FCE20 with 1 wt.% LiBOB can deliver a capacity retention of 87%. The fast-charging electrolytes such as LiPFe salt in DMC / FEC / MTFA with 1 wt.% LiBOB additives were used for this study. Pouch full cell data, which are considered more reliable, will be displayed and discussed in the following sections.Table 2. The solvent diffusion coefficient is based on 2D1H and19F DOSY NMR spectra.Electrolytes Solvents Diffusion coefficient code D (m2s-1)Ethylene carbonate (EC) 5.05 x 10-1°LP57 Ethyl methyl carbonate 5.23 x 10-1°(EMC)Dimethyl carbonate (DMC) 5.70 x 10-1°FCEO Fluoroethylene carbonate 5.02 x 10-1°(FEC)Dimethyl carbonate (DMC) 6.88 x 10-1° crcon A Fluoroethylene carbonate 5.71 x 10-1°FUE2U-MA (FEC)Methyl acetate (MA) 6.59 x 10-1°Dimethyl carbonate (DMC) 6.04 x 10-1°Fluoroethylene carbonate 5.55 x 10-1°FCE20 (FEC)Methyl trifluoroacetate 8.24 x 10-1°(MTFA)

[0227] After determining the basic electrolyte recipe, more fundamental tests, including coulombic efficiency measurements, high-voltage stability measurements, low-temperature capability tests, and thermal stability evaluations, were performed on the commercial LP57 and FCE20 electrolytes. First, as shown in Figs. 5A and 5B, the SEM images of Li plating morphology illustrate that the FCE20 electrolyte can suppress the formation of needle-shape Li dendrites and promote a smooth Li morphology. A coulombic efficiency (CE) test was performed in Cu | Li anode-free cells to further investigate the compatibility of FCE20 with Li-metal anode. As seen, the Li CE of the LP57 cell is only 76.68%, which can be significantly improved to 98.39% with FCE20 (Fig. 5C). Although Li CE is usually considered not important in full cells with graphite anode, it becomes an important parameter in full cells under XFC operating conditions because metallic Li formed at the graphite anode under high current densities, albeit small in quantity, can cause dramatic capacity fading when lacking proper stabilization. Without wishing to be bound by any theory, it was assumed that such behavior is a reason for the quick capacity decay observed on cells in Fig. 4A. Furthermore, the Li | NMC811 half-cell data were collected, as shown in Figs. 5D and 5E. The formation cycle charge-discharge curves of the NMC81 1 cells with LP57 and FCE20 electrolytes are well overlapped, and the cellswith FCE20 show a stable cycling performance, further demonstrating good compatibility of FCE20 with Li-metal anode in half cells.

[0228] The high-voltage stability was evaluated with the linear sweep voltammetry (LSV) method, as shown in Fig. 6A. The current density originates from the electrochemical oxidation of the electrolyte. Specifically, it was found that LP57 is stable only up to 4.52 V, while FCE20 does not experience evident electrochemical decomposition until 4.65 V. Although at the voltage ranges of 4.65 - 4.8 V and 5.2 - 5.6 V, FCE20 shows a similar or better oxidation stability than LP57. Additionally, to also demonstrate the compatibility of FCEs with highly reactive ultrahigh-Ni cathodes, pouch full cells by pairing LiNi0.9Mn0.05Co0.05O2 (NMC900505) cathode with graphite anode were tested. As shown in Fig. 6B, both the LP57 and FCE20 cells operated at a charge-discharge rate of C / 3-C / 3 show a stable cycling performance. Interestingly, the FCE20 cells show a higher capacity than LP57 cells, suggesting, without being bound by any theory, a suppressed loss of active Li during formation cycles in FCE20 cells. Overall, it can be concluded that the FCE20 electrolyte shows good chemical and electrochemical stabilities at high voltages.

[0229] Third, the low-temperature performance of FCE20 was evaluated at -20 °C (Figs. 7A-7D). As first shown in Fig. 7A, interestingly, the curvature in the first-cycle charge-discharge profile in the LP57 cell changes dramatically when compared to the cell cycled at room temperature, which could be attributed to electrolyte solidification and poor lithium-ion conduction. Nevertheless, the FCE20 cell can still deliver high capacities of 150 mA h g-1and 100 mA h g-1at, respectively, at C / 10 and C / 2 rates (Figs. 7B and 7C). In sharp contrast, the LP57 cell can only deliver a first cycle discharge capacity of 95 mA h g-1and suffers from a quick capacity fade even at the C / 10 rate, ending up delivering only ~ 10 mA h g-1at the C / 2 rate with a low CE (Fig. 7D).

[0230] The safety performance of the FCE20 electrolyte was evaluated with a flammability test and differential scanning calorimetry (DSC). Photographic images in Fig. 8A display the combustion process of electrolyte-soaked glass fiber strips ignited with a lighter. As seen, the combustion of LP57 is more violent and lasts longer (> 8s) when compared to FCE20. After combustion, LP57 glass fibers turn to be blacker than the FCE20 glass fibers, indicating a higher temperature realized during the combustion of LP57 leads to a higher degree of carbonization (Fig. 8B).The DSC experiments in Fig. 8C were conducted based on a mixture of charged NMC81 1 cathode (240 mA h g-1) and electrolytes. As seen, the exothermic peak with LP57 is located at 202.6 °C, which is accompanied by a significant amount of heat release (1 ,529 J g-1). In sharp contrast, it was found that the use of FCE20 can postpone the exothermic reaction by ~ 20 °C to 223.2 °C and reduce the heat release to 1 ,160 J g-1. The flammability tests and DSC measurements suggest that the FCE20 electrolyte, particularly the use of MTFA, can ameliorate the safety performance of LIBs.

[0231] After the above fundamental tests, practical pouch full cells were assembled based on a variety of electrolytes that are listed in Table 1 . All pouch cells were placed in a 33 °C environmental chamber for long-term and fast charging at a charge-discharge rate of 4C-2C. This was carried out to maintain reasonable charge transfer kinetics and to prevent any unexpected temperature fluctuations. Abrupt temperature drops, especially for cells under extreme operating conditions, can lead to irreversible capacity degradation and adversely affect cell performance. Figs. 9A- 9J illustrates the charge and discharge profiles of the 1stand 4thcycles during the formation cycles at a C / 10 rate. All cells with varying electrolyte formulations exhibit similar charge and discharge capacities. This consistency ensures the high quality of cathodes, allowing focus exclusively on the comparative study of different electrolyte formulations. The reversibility of the phase transitions is clearly depicted in the dQ / dV“1curves for the pouch full cells (Figs. 10A-10J). It was found that regardless of the specific electrolyte used, all cells undergo identical hexagonal (Hl )-monoclinic (M)-hexagonal (H2)-hexagonal (H3) phase transitions during the charge and discharge processes, and the redox peaks manifest at similar voltages.

[0232] In Figs. 11 A and 11 B, the 1stcycle dQ / dV-1profiles for each electrolyte formulation are plotted together to provide a comprehensive and detailed comparison. Several distinctive features become evident at the voltage window ranging from 1 to 3 V. The first redox peak, occurring at approximately 1 .9 V, corresponds to the reduction of LiBOB, while the reduction of MTFA takes place around 2.4 V. Additionally, the reductions of FEC and EC exhibit peaks at 2.7 V and 2.8 V, respectively. During the formation cycles, these solvent reductions contribute to the formation of the anode-electrolyte interphase (AEI) on the graphite anode.Without wishing to be bound by any theory, it is hypothesized that the decomposition of MTFA (2.4 V) before EC (2.8 V) in the cell facilitates the formation of a favorable thin SEI layer with fast lithium-ion transport on the graphite surface, which allows fast charge capability and better low-temperature performance. Although LiBOB decomposes even earlier than MTFA, the composition and morphology of the SEI formed are critical. In essence, the decomposition of the fluorinated ester MTFA at a lower voltage before the other solvents decompose facilitates the formation of a smooth, thin, fluorine-rich SEI on the anode.

[0233] Upon a closer examination of the cycling profiles for each electrolyte composition, an intriguing observation was found. LP57, FCEO, and FCE5 all exhibit a significant initial capacity fade at high C rates, as depicted in Figs. 12A-12J and Fig. 13. Generally, this initial capacity fade can be attributed to a substantial loss of lithium inventory due to the formation of reactive metallic Li at the anode side. While the cells with no MTFA added into the electrolyte or those with very small amounts of MTFA do not completely eliminate the initial capacity loss behavior, they do exhibit a longer period of time before the capacity retention drops to 80% compared to LP57. Starting from an MTFA ratio of 10-15%, the initial capacity fade is successfully eliminated from the cycling profile, and the discharge capacity is well maintained at around 170 mA h g-1with a capacity retention of around 88-90% after 1 ,000 cycles. Note that a higher capacity retention of FCE20 than FCE20-MA is observed, illustrating the effectiveness of the fluorine substitution strategy for esters. In Figure 14A, the cells with FCE20 have finished more than 2,000 cycles with a remarkable capacity retention of over 80%, surpassing the baseline LP57 electrolyte, which only retained around 58% of its original capacity after 1 ,000 cycles.

[0234] Notably, the coulombic efficiency of FCE20 is slightly higher than that of LP57 (Fig. 14B). Again, without wishing to be bound by any theory, it was suggested that the FCE improves lithium intercalation kinetics, allowing most lithium ions from the cathode to migrate to the anode through the SEI without undergoing plating on the surface of the anode to form metallic lithium at high C rates.

[0235] Electrochemical impedance spectroscopy (EIS) measurements were carried out with the pouch full cells after 100 cycles and 1 ,000 cycles (Fig. 14C). In the Nyquist plots, the diameter of the semicircles corresponds to the magnitude of the resistance. Specifically, the first semicircle corresponds to the Ohmic resistance ofthe surface film (RSf) at the interfaces of the electrodes. The second semicircle represents the charge-transfer resistance (Ret) across the electrode surface. This semicircle reflects the resistance encountered by the electrochemical reactions occurring at electrode-electrolyte interfaces (EEI), such as the movement of ions or electrons during charge and discharge processes. Even though the Rst and Ret values were found to be similar for both cases after 100 cycles, the cells with LP57 displayed larger diameters for the second semicircle after 1 ,000 cycles.

[0236] The cycled graphite electrodes were retrieved from the LP57 and FCE20 pouch cells, as shown in Figs. 15A and 15B. Upon examining the electrode surfaces, it is evident that the graphite electrodes harvested from the pouch cells with LP57 feature a uniformly distributed layer of metallic lithium covering the entire surface. This extensive lithium coverage contributes to an increase in cell impedance. SEM images further confirm that fewer lithium dendrites have formed on the surface of graphite in the FCE20 cell. In stark contrast, the graphite particles from the electrode that were extracted from the LP57 pouch cells are barely visible in the SEM images, as they are entirely covered by a thick layer of solid metallic lithium formed by the continuous deposition of numerous lithium dendrites. This observation provides further evidence that lithium-ion diffusion kinetics through LP57 electrolytes are slower compared to that through FCE20. It is possible that this slower diffusion is indicative of higher desolvation energy for LP57 in comparison to FCE20, which can influence the overall performance and efficiency of the cell over extended cycling. Additional electrolyte characterization techniques will be applied in the following section to identify the specific properties of FCE that enhance rapid charge-transfer kinetics under fast charging rates. These techniques will help in gaining a deeper understanding of the factors that influence and improve the efficiency of fastcharging processes in the context of the studied electrolyte formulations.

[0237] To gain a deep insight into interphase chemistry, ToF-SIMS was first utilized to unveil the chemistry and architecture of the cathode-electrolyte interphase (CEI). Fig. 16A shows the normalized depth profiles of several secondary-ion fragments from NMC811 cathodes after 1 ,000 cycles with LP57 and FCE20 electrolytes. Specifically, PO2“ stems from the decomposition products of LiPFe; NiFa-, CoFa-, and MnFg- represent active cathode material dissolution products resulting from reactions between HF and the cathode; LiF2_represents both active-material dissolutionproducts and Li F precipitates from the electrolyte; C2HO- stems from electrolyte solvent decomposition reactions;62Ni“ represents the bulk cathode material. The thickness of CEI is determined by the point where the intensity of the LiF2_fragment decreases to 50% of its maximum intensity. As seen, the CEI of the cathode in LP57 is ~ 190 nm thick, which is significantly thicker than that in FCE20 (~ 60 nm).

[0238] Furthermore, the CEI in LP57 is characterized with a bi-layered structure with PO2“ / C2HO“ and NiF3“ / CoF3“ / MnF3“ / LiF2“ constituting, respectively, the outer and inner layers. The morphology of CEI was further studied with CEI 3D rendering images shown in Figs. 16B and 16C. The CEI fragments in LP57 not only penetrate deeper from the surface but also have a more inhomogeneous distribution on the surface of the cathode. Without wishing to be bound by any theory, the 3D rendering overlap plots in Fig. 16C suggest that compared to the LP57 CEI, FCE20 CEI is more inorganic-rich with a higher concentration of PO2-. This is further validated by the peak intensity comparison plot in Fig. 16D. Specifically, the intensity of the PO2“ fragment in FCE is three times higher than that in LP57; in sharp contrast, the organic C2HO- fragment in LP57 is about five times higher than that in FCE. Meanwhile, the active-material dissolution reaction is more pronounced in LP57 than in FCE, as indicated by a higher concentration of NiFs- and Li F2_in LP57.

[0239] To further understand the CEI properties, the dynamic behavior of interphases at the cathode was investigated based on the region-of-interest analysis. As shown in Figs. 17A and 17B, based on the hot regions of C3- and60Ni- fragments, the detect area is divided into carbon black (ROI-1 ) and active material (ROI-2) regions. ROI-1 is enriched with the side reaction fragment C2F-; while ROI-2 is enriched with the electrolyte oxidation product (C2O-) and active material dissolution product (NiFs-). As illustrated in Fig. 17C, the characteristic fragments on ROI-1 and ROI-2 in FCE20 remain in the respective regions without severe inter-region penetrations or migrations. However, the C2F- fragment on carbon black is penetrated or migrated significantly to the active material region, and the C2O- and NiFs- fragments also migrated from the active material region to the carbon black region. This suggests that the CEI in FCE20 is more protective against not only electrolyte side reactions but also dynamic CEI component migrations within the cathode electrode.

[0240] As has been shown in Figs. 15A-15B, the cycled graphite anode, particularly when paired with LP57 electrolyte, displays a top metallic “dead” Li layer and a bottom graphite layer. Therefore, it is important to characterize the SEIs on both the metallic Li layer and the graphite layer. In this regard, ToF-SIMS was conducted on both layers. As first shown in Fig. 18A, the normalized depth profiles of several critical fragments are displayed. Among them, PO2“ stems from the decomposition products of LiPFe; Ni“ represents active-material crossover product; LiF2“ represents Li F that results from the decomposition of F-containing solvents or salt; C2HO- stems from electrolyte solvent decomposition reactions; Ce“ represents the polymer SEI components; Li, LiH, and Li2“ represent, respectively, all Li-containing species, LiH, and metallic Li. The thickness of SElu is determined by the point where the intensity of Ni“ fragment decreases to 50% of its maximum intensity.

[0241] As seen, the SEI in FCE20 Li is ~ 35 nm, moderately thinner than that in LP57 Li (50 nm). Furthermore, the same group of secondary-ion fragments was utilized to understand the SEI architecture of the bottom graphite phase (Fig.18B). In this case, Ce“ represents the bulk graphite instead of surface polymer SEI component, and the thickness of SEIor is determined by the point where the intensity of Li- fragment decreases to 50% of its maximum intensity. Not surprisingly, the SEI thickness in LP57 graphite is ~ 580 nm, one magnitude thicker than that of FCE20 graphite (50 nm). Additionally, the surface roughness of both SEIs on the Li and graphite phases is higher im LP57 than in FCE, as illustrated by the narrow distribution of SEI detection depth at the thinner regions in Fig. 18C.

[0242] A quantitative analysis of the SEI components is presented in Figs. 19A-19B. As seen for the SEI on the metallic Li layer, the most evident difference between LP57 and FCE20 is that the LiF2“ is more than two times higher on FCE20 Li than on LP57 Li. This likely benefits from the use of highly fluorinated MTFA solvent. The enriched LiF on Li metal has been reported to protect the reactive Li from continuous reactions with the electrolyte. As for the graphite anode, however, the differences between FCE20 and LP57 are more evident. Even at the bottom graphite phase, the dead Li on LP57 graphite, including metallic Li (Li2“), is more than four times higher than that on FCE20 graphite. Moreover, the organic decomposition products are also significantly higher on LP57 graphite than on FCE20 graphite. Both the formation of organic products and dead Li can be catalyzed by the transition-metal depositscrossed over from the cathode, as demonstrated by the intensity comparison of Ni- fragment. Finally, the most important SEI component, LiF, is also significantly more concentrated on the graphite in FCE20 than in LP57.EXAMPLE 2

[0243] The solvation structures and solvate distribution of FCE20, FCE65, and commercial LP57 electrolytes were evaluated by the molecular dynamic (MD) simulation, as depicted in FIG. 20A and FIG. 21 . As seen, the radical distribution function (RDFs) plot demonstrates that all the carbonate solvents (Li-Osoivent) and PF6- anion (Li-Fpre) own a strong solvation power and coordinate with Li+in the first and second solvation shells at around 2 and 4 A, respectively. In contrast, MTFA exhibits very weak coordination with Li+and mainly resides outside the solvation shells, even in FCE65 with 65 wt.% of MTFA (FIG. 21 ). Therefore, MTFA primarily serves as a diluent in the FCE system, which means the effective LiPFe concentration gradually increases in FCEs with higher MTFA contents.

[0244] Interestingly, the employment of MTFA can influence the distribution of carbonate solvents and PFe- anion in the first and second solvation shells, respectively. Specifically, the first DMC g(r) peak in FCE20 is positioned closer to the central Li+ion compared to the carbonate solvents in LP57; conversely, the second PF6- g(r) peak of FCE20 shifts outwards from 3.8 A to 4.2 A, accompanied by the emergence of a third PFe- g(r) peak at ~ 5.2 A. It is noteworthy that even though the effective concentration of LiPFe in FCE20 (~ 1 .5 M) is 50% higher than that in LP57 (1 M), the intensities of the PFe- peaks in the first solvation shell of FCE20 and LP57 are similar. Collectively, these shreds of evidence suggest that MTFA can enhance the solvation of the carbonate solvent while inducing PFe- anions in the second and third shells to move away from Li+, as schematically illustrated in FIG. 20D.

[0245] 7Li and19F NMR data in FIG. 20B support this hypothesis and provide additional insights into the solvation structure. As anticipated, the7Li peak shifts more negatively with increasing MTFA content in FCEs, owing to the enhanced solvent solvation and rise in effective LiPFe concentration. Therefore, one would expect that the PFe- peaks in19F NMR spectra should experience a positive shift for FCEs with higher MTFA contents, because the shift of7Li peak generally originates from Li+-PFe- interactions. Surprisingly, the PFe- peaks display a negative shift fromFCEO to FCE65. This phenomenon is likely attributed to several factors: (i) closer coordination of IJ+-ODMC, minimizing interactions between Li+and PFe-, (ii) outward shift of PF6- anion in the second solvation shell, weakening Li+-PFe- interactions, and (iii) the shielding effect of MTFA as a diluent, disrupting the interactions between solvation clusters.

[0246] Furthermore, FTIR data corroborate the NMR findings. As depicted in FIG. 20C, FIGs. 22A-24B, and Example 3, the addition of MTFA in saturated LiPFe electrolytes reduces the intensity ratio of ion-paired PFe- and free PFe- peaks, but increases the intensity ratio of corradiated DMC and free DMC peaks. This phenomenon is termed the solvent-solvation enhancement effect (SSEE). It is conceivable that MTFA may raise the solubility of LiPFe in carbonated-based electrolytes due to SSEE. As confirmed in FIG. 20E and FIG. 25, although MTFA itself can only dissolve a negligible amount of LiPFe, the solubility of LiPFe in a DMC- FEC mixture or pure DMC can be enhanced with the gradual addition of MTFA. In sharp contrast, adding conventional diluents, such as 1 ,1 ,2,2-tetrafluoroethyl 2, 2,3,3- tetrafluropropyl ether (TTE), into a saturated electrolyte will cause immediate salt participation, as shown in FIG. 26. The ability of MTFA to enhance the solvation ability of solvents rather than anion solvation (i.e., SSEE) may facilitate the desolvation of Li+at the graphite interface and promote the formation of a solvent (including MTFA itself)-derived SEI with a high ionic conductivity, advantageous for fast-charging and low-temperature operations. On top of that, two-dimensional (2D) diffusion-ordered spectroscopy (DOSY) data in FIGs.2A-3D and Table 3 reveal that MTFA in FCE20 possesses the highest diffusion coefficient and can enhance the diffusivity of other solvents, thereby promoting high ionic conductivity for FCEs (FIG. 28).Table 3. The solvents diffusion coefficient based on 2D1H and19F DOSY-NMR spectroscopyEXAMPLE 3Analysis of the solvation structure of MTFA-based FCEs.

[0247] As has been shown in FIG. 20C, an increase in the MTFA content in FCEs leads to a gradual increase in the ratio of solvated DMC to free DMC peaks. This is attributed to the low solubility of LiPFe in MTFA, resulting in an effective increase in LiPFe concentration in FCEs with higher MTFA content, when the overall LiPFe concentration is consistently maintained at 1.2 M in all FCEs. Typically, as the salt concentration increases, the number of contact ion pair (CIP) and aggravate (AGG) solvates will also increase, resulting in a higher ratio of ion-pair PFe- and free PFe- peaks. This trend is observed in the FTIR data of electrolytes, including LiPFe-DMC, LiPFe-FEC, and LiPFe-MA in FIGs. 23A-24B. However, such an increase in the ratio of ion-pair PFe- and free PFe- peaks in from FCEO to FCE65 is much less pronounced (FIGs. 22A-22B), suggesting that the formation of contact ion pair (CIP) and aggravate (AGG) solvates in MTFA-based electrolytes is less favorable. Due to this suppressed Li+-PFe- coordination, it is conceivable that a greater number of Li+ions will be coordinated with solvents and the ratio of solvated DMC and free DMC peaks should increase. Indeed, as shown by the FTIR data in FIGs. 22A-22B, the ratio of solvated DMC and free DMC peaks is 0.85 for the 1 M LiPFe DMC / FEC electrolyte, which increases to 1 .70 for the 3 M LiPFe DMC / FEC electrolyte; while after adding the MTFA solvent, this ratio increases to 1 .97, illustrating a more favorable coordination of Li+with the solvent than anion in MTFA-based FCEs. This phenomenon, termed solvent-solvation enhancement effect (SSEE), allows for a higher solubility of LiPFe in the electrolyte, as evidenced by FIG. 20E and FIG. 25.EXAMPLE 4Experimental section:

[0248] The solvent and electrolyte structures were first characterized by a NICOLET iS5 Fourier-transform infrared spectrometer (Thermo Fisher Scientific). An iD5 attenuated total reflectance component was installed for the electrolyte test. In addition, nuclear magnetic resonance spectroscopy (NMR) data were acquired with a Bruker Avance NEO 400 MHz NMR spectrometer. Specifically, a coaxial insert tube containing 100 pL of D6-DMSO was positioned within the coaxial outer tube, which was filled with 500 pL of fresh electrolyte. To obtain the7Li NMR data, the solution in the inner tube was replaced by 100 pL 0.1 mol L-1LiPFe in D6-DMSO solution. Two-dimensional (2D) diffusion-ordered spectroscopy (DOSY) of1H and19F was conducted on a Varian 600 MHz NMR spectrometer to obtain the diffusion coefficients of different electrolytes.

[0249] Atomic molecular dynamics simulations were performed with the optimized potentials for liquid simulations all-atom (OPLS-2009IL and OPLSAAM) force field (GROMACS simulation package). Three electrolytes, LP57, FCE20, and FCE65 were simulated, which contain 80 LiPFe-330 EC-650 EMC, 98 LiPFe-210 FEC-590 DMC-200 MTFA, and 107 LiPF6-1 10 FEC-310 DMC-580 MTFA molecules, respectively. The molecules were first randomly placed in cubic boxes with a volume of approximately 1 ,000 nm3. After thousands of steps of energy minimization, the systems were equilibrated for 10 ns, followed by the production runs of 20 ns under the NPT ensemble. The system temperature (298 K) and pressure (1 atm) were controlled by Nose-Hoover and Parrinello-Rahman methods, respectively. A cutoff scheme of 1 .2 nm was implemented for the non-bonded interactions, and the Particle Mesh Ewald method with a Fourier spacing of 0.1 nm was applied for the long-range electrostatic interactions. All covalent bonds with hydrogen atoms were constraint by the LINCS algorithm.

[0250] The devices, systems, and methods of the appended claims are not limited in scope by the specific devices, systems, and methods described herein, which are intended as illustrations of a few aspects of the claims. Any devices, systems, and functionally equivalent methods are intended to fall within the scope of the claims. Various modifications of the devices, systems, and methods, in addition to thoseshown and described herein, are intended to fall within the scope of the appended claims. Further, while only certain representative devices, systems, and method steps disclosed herein are specifically described, other combinations of the devices, systems, and method steps are also intended to fall within the scope of the appended claims, even if not specifically recited. Thus, a combination of steps, elements, components, or constituents may be explicitly mentioned herein or less; however, other combinations of steps, elements, components, and constituents are included, even though not explicitly stated.

[0251] Although several embodiments of the invention have been disclosed in the foregoing specification, it is understood by those skilled in the art that many modifications and other embodiments of the invention will come to mind to which the invention pertains, having the benefit of the teaching presented in the foregoing description and associated drawings. It is thus understood that the invention is not limited to the specific embodiments disclosed hereinabove and that many modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although specific terms are employed herein, as well as in the claims which follow, they are used only in a generic and descriptive sense and not for the purposes of limiting the described invention or the claims which follow.

[0252] Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of skill in the art to which the disclosed invention belongs. Publications cited herein and the materials for which they are cited are specifically incorporated by reference.

[0253] The claims are not intended to include, and should not be interpreted to include, means-plus- or step-plus-function limitations unless such a limitation is explicitly recited in a given claim using the phrase(s) “means for” or “step for,” respectively.

[0254] In view of the described processes and compositions, hereinbelow are described certain more particularly described aspects of the inventions. These particularly recited aspects should not, however, be interpreted to have any limiting effect on any different claims containing different or more general teachings described herein or that the “particular” aspects are somehow limited in some way other than the inherent meanings of the language and formulas literally used therein.EXEM PLARY ASPECTS

[0255] In view of the described processes and compositions, hereinbelow are described certain more particularly described aspects of the disclosures. These particularly recited aspects should not, however, be interpreted to have any limiting effect on any different claims containing different or more general teachings described herein, or that the “particular” aspects are somehow limited in some way other than the inherent meanings of the language and formulas literally used therein.

[0256] Example 1 . An electrolyte solution comprising: (a) about 5 wt % to about 60 wt % of a fluorinated ester; (b) greater than 0 wt % to less than 100 wt % of at least one solvent selected from fluoroethylene carbonate, difluoroethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl (2,2,2- trifluoroethyl) carbonate, propylene carbonate, trifluoropropylene carbonate, butylene carbonate, methyl acetate (MA), ethyl acetate (EA), methyl propanoate (MP); (c) at least one salt; wherein the wt % is calculated based on a total weight of a) and b); and wherein the electrolyte solution is substantially free of ethylene carbonate (EC).

[0257] Example 2. The electrolyte solution of any one of the Examples herein, particularly Example 1 , wherein the fluorinated ester has a general structure of 0 formula I(I) wherein R1and R2are independently selected from C1-C3 alkyl or C1-C3 fluoroalkyl having two or more fluoro groups; wherein at least one of R1and R2is C1-C3 fluoroalkyl having two or more fluoro groups.

[0258] Example 3. The electrolyte solution of any one of the Examples herein, particularly Example 1 or 2, wherein the fluorinated ester comprises methyl trifluoroacetate (MTFA), ethyl trifluoroacetate (ETFA), methyl 3,3,3- trifluoropropionate (MTFP), 2,2,2-trifluoroethyl acetate (TFEA), 2,2,2-trifluoroethyl propionate (TFEP), methyl difluoroacetate (MDFA), ethyl difluoroacetate (EDFA), methyl 2,3,3,3-tetrafluoro propionate (MTFP), methyl pentafluoropropionate (MPFP), 2,2,2-trifluoroethyl butyrate (TFEB), trifluoroethyl trifluoroacetate (TFETFA) or any combination thereof.

[0259] Example 4. The electrolyte solution of any one of the Examples herein, particularly Examples 1 -3, wherein the at least one salt comprises lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI),lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium bis(oxalato)borate (LiBOB), LiPF6, LiAsF6, LiBF4, LiCF3SO3, LiCIO4, lithium difluoro oxalato borate anion (LiDFOB), lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide (LiTDI), or any combination thereof.

[0260] Example 5. The electrolyte solution of any one of the Examples herein, particularly Examples 1 -4, wherein the at least one salt is present in an amount of about 0.3 M to about 2 M.

[0261] Example 6. The electrolyte solution of any one of the Examples herein, particularly Examples 1 -5, comprises two or more solvents.

[0262] Example 7. The electrolyte solution of any one of the Examples herein, particularly Example 6, wherein a first of the two or more solvents is fluoroethylene carbonate.

[0263] Example 8. The electrolyte solution of any one of the Examples herein, particularly Example 6 or 7, wherein a second of the two or more solvents is selected from ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, and butylene carbonate.

[0264] Example 9. The electrolyte solution of any one of the Examples herein, particularly Examples 5-7, wherein the electrolyte solution comprises methyl trifluoroacetate / fluoroethylene carbonate / dimethyl carbonate.

[0265] Example 10. The electrolyte solution of any one of the Examples herein, particularly Example 9, wherein the at least one salt comprises LiPFe.

[0266] Example 11 . The electrolyte solution of any one of the Examples herein, particularly Example 10, wherein the at least one salt further comprises LiBOB and / or LiDFOB.

[0267] Example 12. The electrolyte solution of any one of the Examples herein, particularly Example 11 , wherein LiBOB and / or LiDFOB are present in amounts greater than 0 wt % to about 5 wt %.

[0268] Example 13. The electrolyte solution of any one of the Examples herein, particularly Examples 7-12, wherein the first solvent is present in an amount of about 10 wt % to about 40 wt %.

[0269] Example 14. The electrolyte solution of any one of the Examples herein, particularly Examples 8-13, wherein the second solvent is present in an amount of about 20 wt % to about 70 wt %.

[0270] Example 15. The electrolyte solution of any one of the Examples herein, particularly Examples 1 -14, wherein the fluorinated ester is present in an amount of about 10 wt % to about 35 wt % or about 15 wt % to about 20 wt %.

[0271] Example 16. The electrolyte solution of any one of the Examples herein, particularly Examples 1 -15, wherein the electrolyte solution exhibits a conductivity greater than about 9 mS / cm to about 20 mS / cm.

[0272] Example 17. The electrolyte solution of any one of the Examples herein, particularly Examples 1 -16, wherein when the electrolyte solution is used in an electrochemical cell, the electrolyte is capable of forming an inorganic-rich interphase layer on at least one electrochemically active surface during an operation of the electrochemical cell.

[0273] Example 18. The electrolyte solution of any one of the Examples herein, particularly Examples 1 -17, wherein the electrolyte solution is substantially free of electrochemical decomposition up to at least 4.65 V.

[0274] Example 19. The electrolyte solution of any one of the Examples herein, particularly Examples 1 -18, wherein the electrolyte solution, when used in a rechargeable battery, supports the rechargeable battery charging up to 4C rate for at least about 500 or at least about 1000 cycles at a deep charge-discharge condition.

[0275] Example 20. The electrolyte solution of any one of the Examples herein, particularly Examples 1 -19, wherein the electrolyte solution is substantially flame resistant.

[0276] Example 21 . A secondary battery comprising: a first electroactive surface configured to behave as an anode; a second electroactive surface configured to behave as a cathode; and an electrolyte solution of any one of Examples 1 -20.

[0277] Example 22. The secondary battery of any one of the Examples herein, particularly Example 21 , further comprising a cathode-electrolyte interphase (CEI) layer disposed on the second electroactive surface and having a thickness of about 10 to about 80 nm.

[0278] Example 23. The secondary battery of any one of the Examples herein, particularly Examples 21 -22, further comprising a solid-electrolyte interphase (SEI) layer disposed on a first electroactive surface and having a thickness of about 10 to about 60 nm.

[0279] Example 24. The secondary battery of any one of the Examples herein, particularly Examples 20-23, wherein a surface of the first electroactive surface is substantially free of dendrites during a charging step.

[0280] Example 25. The secondary battery of any one of the Examples herein, particularly Examples 20-24, wherein the first electroactive surface comprises carbon, silicon, tin, antimony, Li, Na, K, Zn, Ni, Cu, Al, silicon, silicon oxides, Mg, Li alloys, Li intermetallic, or Li compounds.

[0281] Example 26. The secondary battery of any one of the Examples herein, particularly Examples 20-25, wherein the second electroactive surface comprises a metal or a composite material.

[0282] Example 27. The secondary battery of any one of the Examples herein, particularly Examples 20-26, wherein the second electroactive surface comprises layered oxide cathodes, vanadium-based cathode, sulfur-based cathode, manganese-based cathode, rocksalt cathode, disordered rocksalt cathode, lithium- rich cathode, NMC (nickel-manganese-cobalt oxide) cathode, NCA (nickel-cobalt- aluminum oxide) cathode, NFM (nickel-iron-manganese oxide) cathode, LCO (lithium-cobalt oxide) cathode, LFP (lithium iron phosphate) cathode, fluoride-based cathode, sulfur selenium cathode, selenium cathode, tellurium cathode, spinels cathode, olivines cathode, or any combination thereof.

[0283] Example 28. The secondary battery of any one of the Examples herein, particularly Examples 20-27, wherein the battery further comprises a separator.

[0284] Example 29. The secondary battery of any one of the Examples herein, particularly Example 27, wherein the separator comprises polypropylene, polyethylene, glass fiber, or any combination thereof.

[0285] Example 30. The secondary battery of any one of the Examples herein, particularly Examples 20-29, wherein the battery exhibits a charging rate of up to 4C with a cycle life of at least 500 cycles or at least 1000 cycles.

[0286] Example 31 . The secondary battery of any one of the Examples herein, particularly Examples 20-30, wherein the fluorinated ester, the at least one solvent, and / or at least one salt present in the electrolyte solution decompose at a different rate during a battery operation.

[0287] Example 32. The secondary battery of any one of the Examples herein, particularly Example 31 , wherein at least one of the fluorinated ester, the at least onesolvent, and / or at least one salt present in the electrolyte solution decomposes at greater than about 0.9 V (vs. Li / Li+) and thereby forming the SEI of claim 23 on the anode.

[0288] Example 33. The secondary battery of any one of the Examples herein, particularly Examples 20-32, wherein the battery exhibits a Coulombic efficiency greater than about 98% over at least about 500 cycles at a charge rate of up to 4C.

[0289] Example 34. The secondary battery of any one of the Examples herein, particularly Examples 20-33, wherein the battery exhibits capacity retention of about 80% or greater after at least about 2000 cycles at a 4C rate.

[0290] Example 35. The secondary battery of any one of the Examples herein, particularly Examples 20-34, wherein the battery exhibits a capacity retention of at least greater than about 80 % for at least 2,000 cycles at a 4C rate.

[0291] Example 36. The secondary battery of any one of the Examples herein, particularly Examples 20-34, wherein the battery exhibits a capacity retention of at least greater than about 90 % for at least 500 cycles at a 4C rate.

[0292] Example 37. The secondary battery of any one of the Examples herein, particularly Examples 20-36, wherein the secondary battery is capable of operating in a temperature range from about -25 °C to about 60 °C.

[0293] Example 38. The secondary battery of any one of the Examples herein, particularly Examples 20-37, wherein the secondary battery exhibits a specific capacity of about 100 mA h g-1to about 300 mA h g-1at charge rates up to 4C.

Claims

CLAIMS1. An electrolyte solution comprising: a) about 5 wt % to about 60 wt % of a fluorinated ester; b) greater than 0 wt % to less than 100 wt % of at least one solvent selected from fluoroethylene carbonate, difluoroethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl (2,2,2-trifluoroethyl) carbonate, propylene carbonate, trifluoropropylene carbonate, butylene carbonate, methyl acetate (MA), ethyl acetate (EA), methyl propanoate (MP); c) at least one salt; wherein the wt % is calculated based on a total weight of a) and b); and wherein the electrolyte solution is substantially free of ethylene carbonate (EC).

2. The electrolyte solution of claim 1 , wherein the fluorinated ester has a general structure of formula Iwherein R1and R2are independently selected from C1-C3 alkyl or C1-C3 fluoroalkyl having two or more fluoro groups; wherein at least one of R1and R2is C1-C3 fluoroalkyl having two or more fluoro groups.

3. The electrolyte solution of claim 1 or 2, wherein the fluorinated ester comprises methyl trifluoroacetate (MTFA), ethyl trifluoroacetate (ETFA), methyl 3,3,3-trifluoropropionate (MTFP), 2,2,2-trifluoroethyl acetate (TFEA), 2,2,2- trifluoroethyl propionate (TFEP), methyl difluoroacetate (MDFA), ethyl difluoroacetate (EDFA), methyl 2,3,3,3-tetrafluoro propionate (MTFP), methyl pentafluoropropionate (MPFP), 2,2,2-trifluoroethyl butyrate (TFEB), trifluoroethyl trifluoroacetate (TFETFA) or any combination thereof.

4. The electrolyte solution of any one of claims 1 -3, wherein the at least one salt comprises lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium bis(oxalato)borate (LiBOB), LiPFe, LiAsFe, LiBF4, UCF3SO3, LiCICU, lithium difluoro oxalato borate anion(LiDFOB), lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide (LiTDI), or any combination thereof.

5. The electrolyte solution of any one of claims 1 -4, wherein the at least one salt is present in an amount of about 0.3 M to about 2 M.

6. The electrolyte solution of any one of claims 1 -5, comprising two or more solvents.

7. The electrolyte solution of claim 6, wherein a first of the two or more solvents is fluoroethylene carbonate.

8. The electrolyte solution of claim 6 or 7, wherein a second of the two or more solvents is selected from ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, and butylene carbonate.

9. The electrolyte solution of any one of claims 5-7, wherein the electrolyte solution comprises methyl trifluoroacetate / fluoroethylene carbonate / dimethyl carbonate.

10. The electrolyte solution of claim 9, wherein the at least one salt comprises LiPF6.11 . The electrolyte solution of claim 10, wherein the at least one salt further comprises LiBOB and / or LiDFOB.

12. The electrolyte solution of claim 11 , wherein LiBOB and / or LiDFOB are present in amounts greater than 0 wt % to about 5 wt %.

13. The electrolyte solution of any one of claims 7-12, wherein the first solvent is present in an amount of about 10 wt % to about 40 wt %.

14. The electrolyte solution of any one of claims 8-13, wherein the second solvent is present in an amount of about 20 wt % to about 70 wt %.

15. The electrolyte solution of any one of claims 1 -14, wherein the fluorinated ester is present in an amount of about 10 wt % to about 35 wt % or about 15 % wt to about 20 wt %.

16. The electrolyte solution of any one of claims 1 -15, wherein the electrolyte solution exhibits conductivity greater than about 9 mS / cm to about 20 mS / cm.

17. The electrolyte solution of any one of claims 1 -16, wherein when the electrolyte solution is used in an electrochemical cell, the electrolyte is capable of forming an inorganic-rich interphase layer on at least one electrochemically active surface during an operation of the electrochemical cell.

18. The electrolyte solution of any one of claims 1 -17, wherein the electrolyte solution is substantially free of electrochemical decomposition up to at least 4.65 V.

19. The electrolyte solution of any one of claims 1 -18, wherein the electrolyte solution, when used in a rechargeable battery, supports that rechargeable battery charging up to 4C rate for at least about 500 or at least about 1000 cycles at a deep charge-discharge condition.

20. The electrolyte solution of any one of claims 1 -19, wherein the electrolyte solution is substantially flame resistant.21 . A secondary battery comprising: a first electroactive surface configured to behave as an anode; a second electroactive surface configured to behave as a cathode; an electrolyte solution of any one of claims 1 -20.

22. The secondary battery of claim 21 , further comprising a cathode-electrolyte interphase (CEI) layer disposed on the second electroactive surface and having a thickness of about 10 to about 80 nm.

23. The secondary battery of any one of claims 21 -22, further comprising a solidelectrolyte interphase (SEI) layer disposed on a first electroactive surface and having a thickness of about 10 to about 60 nm.

24. The secondary battery of any one of claims 20-23, wherein a surface of the first electroactive surface is substantially free of dendrites during a charging step.

25. The secondary battery of any one of claims 20-24, wherein the first electroactive surface comprises carbon, silicon, tin, antimony, Li, Na, K, Zn, Ni, Cu, Al, silicon, silicon oxides, Mg, Li alloys, Li intermetallic, or Li compounds.

26. The secondary battery of any one of claims 20-25, wherein the second electroactive surface comprises a metal or a composite material.

27. The secondary battery of any one of claims 20-26, wherein the second electroactive surface comprises layered oxide cathodes, vanadium-based cathode, sulfur-based cathode, manganese-based cathode, rock-salt-based cathode, disordered rocksalt cathode, lithium-rich cathode, NMC (nickel-manganese-cobalt oxide) cathode, NCA (nickel-cobalt-aluminum oxide) cathode, NFM (nickel-iron- manganese oxide) cathode, LCO (lithium-cobalt oxide) cathode, LFP (lithium iron phosphate) cathode, fluoride-based cathode, sulfur selenium cathode, selenium cathode, tellurium cathode, spinels cathode, olivines cathode, or any combination thereof.

28. The secondary battery of any one of claims 20-27, wherein the battery further comprises a separator.

29. The secondary battery of claim 27, wherein the separator comprises polypropylene, polyethylene, glass fiber, or any combination thereof.

30. The secondary battery of any one of claims 20-29, wherein the battery exhibits a charging rate of up to 4C with a cycle life of at least 500 cycles or at least 1000 cycles.31 . The secondary battery of any one of claims 20-30, wherein the fluorinated ester, the at least one solvent, and / or at least one salt present in the electrolyte solution decompose at a different rate during a battery operation.

32. The secondary battery of claim 31 , wherein at least one of the fluorinated ester, the at least one solvent, and / or at least one salt present in the electrolyte solution decomposes at greater than about 0.9 V (vs. Li / Li+) and thereby forming the SEI of claim 23 on the anode.

33. The secondary battery of any one of claims 20-32, wherein the battery exhibits a Coulombic efficiency greater than about 98% over at least about 500 cycles at a charge rate of up to 4C.

34. The secondary battery of any one of claims 20-33, wherein the battery exhibits capacity retention of about 80% or greater after at least about 2000 cycles at a 4C rate.

35. The secondary battery of any one of claims 20-34, wherein the battery exhibits a capacity retention of at least greater than about 80 % for at least 2000 cycles at a 4C rate.

36. The secondary battery of any one of claims 20-34, wherein the battery exhibits a capacity retention of at least greater than about 90 % for at least 500 cycles at a 4C rate.

37. The secondary battery of any one of claims 20-36, wherein the secondary battery is capable of operating in a temperature range from about -25 °C to about 60 °C.

38. The secondary battery of any one of claims 20-37, wherein the secondary battery exhibits a specific capacity of about 100 mA h g-1to about 300 mA h g-1at charge rates up to 4C.

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