Electrolyte chemical formulations for energy storage devices

Abstract

The present invention discloses an ion-conducting electrolyte comprising a liquefied gas solvent that exhibits a low global warming potential (GWP) and low flammability, while also generating a solid electrolyte interface favorable in electrochemical apparatuses, thereby maintaining high performance and cycle life. The ion-conducting electrolyte comprises a multi-component solvent mixture containing a low-GWP solvent and a non-low-GWP solvent. The total GWP of the multi-component solvent mixture is at least 50% lower than the GWP of the non-low-GWP solvent alone.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the priority of U.S. Application No. 63 / 450745, filed on March 8, 2023, the entire content of which is incorporated herein by reference.

[0002] This application also relates to the following applications and patents, each of which is incorporated herein by reference in its entirety: U.S. Patent No. 10,608,284, issued on March 31, 2020; U.S. Patent No. 10,998,143, issued on May 4, 2021; U.S. Patent No. 10,784,532, issued on September 22, 2020; U.S. Patent No. 11,088,396, issued on August 10, 2021; U.S. Patent 10,873,070, issued on December 22, 2020; U.S. Patent 11,342,615, issued on May 24, 2022; PCT / US20 / 26086, filed on April 1, 2020; PCT / US22 / 31594, filed on May 31, 2022; PCT / US23 / 11864, filed on January 30, 2023; PCT / US23 / 17720, filed on April 6, 2023; PCT / US23 / 28104, filed on July 19, 2023; PCT / US23 / 28105, filed on July 19, 2023; PCT / US23 / 35766, filed on October 24, 2023; PCT / US24 / 16784, filed on February 21, 2024; U.S. Application No. 63 / 418703, filed on October 24, 2022; U.S. Application No. 63 / 461252, filed on April 22, 2023; U.S. Application No. 63 / 461387, filed on April 24, 2023; U.S. Application No. 63 / 470174, filed on May 31, 2023, and U.S. Application No. 63 / 534213, filed on August 22, 2023.

[0003] The present invention relates to the chemical composition of electrolytes for energy storage devices.

Background Art

[0004] Typical electrolytes and related technologies for lithium-ion batteries consist of flammable liquid solvents. Liquid electrolytes often limit the performance of battery cells in terms of temperature operation, power, energy, cycle life, and safety.

[0005] Another class of electrolytes is liquefied gas electrolytes, in which the main solvent is usually in the gas phase under standard temperature and pressure, but can be liquefied under moderate pressure and mixed with salts to form a conductive electrolyte. Liquefied gas electrolytes are used in energy storage devices, such as batteries or capacitors, and can exhibit excellent performance in terms of temperature, power, energy, and / or safety.

[0006] Liquefied gas electrolytes may consist of solvents with moderate to high global warming potential (GWP), which is a measure of a molecule's contribution to global warming due to radiative forcing, compared to carbon dioxide. For example, if the GWP of CO2 is defined as 1, fluoromethane has a GWP of 92 and difluoromethane has a GWP of 675. It would be beneficial to utilize liquefied gas solvents that exhibit a low or zero effective GWP while maintaining other desirable properties for an ideal electrolyte solvent, such as high polarity, chemical stability, non-toxicity, and low cost. Furthermore, some of these high-GWP, flammable liquefied gas solvents have also been shown to form optimal solid electrolyte interfaces (SEIs) for effective cell operation.

[0007] It would be beneficial to identify other liquefied gas solvents that exhibit low GWP and low flammability while also creating a favorable solid electrolyte interface in battery devices, thereby maintaining high performance and cycle life. [Overview of the Initiative]

[0008] This specification discloses an ion-conducting electrolyte comprising a salt and a liquefied gas solvent mixture having a vapor pressure greater than 100 kPa at a temperature of 293.15 K. This mixture comprises a first solvent component and a second solvent component. The first solvent component may have a GWP of less than 10, and the second component may have a GWP greater than 80. By mixing this multi-component solvent containing low-GWP and non-low-GWP components, the total GWP of the ion-conducting electrolyte can be reduced. The relative amounts of the first and second solvent components may preferably be selected to reduce the GWP of the liquefied gas solvent mixture to less than 10% of the GWP of the second solvent component, more preferably less than 50% of the GWP of the second solvent component, and even more preferably less than 70% of the GWP of the second solvent component.

[0009] Examples of the first solvent component include hydrochloroolefins, hydrochlorofluoroolefins, perchloroolefins, and perfluoroolefins, 1,1-dichloroethene, vinyl chloride, trichloroethene, dichloroethene, chlorofluoroethene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, trans-1-chloro-3,3,3-trifluoropropene, and their isomers.

[0010] Examples of the second solvent component include dimethyl ether, methyl ethyl ether, fluoromethane, difluoromethane, trifluoromethane, fluoroethane, tetrafluoroethane, pentafluoroethane, 1,1-difluoroethane, 1,2-difluoroethane, 1,1,1-trifluoroethane, 1,1,2-trifluoroethane, 1,1,1,2-tetrafluoroethane, 1,1,2,2-tetrafluoroethane, pentafluoroethane, chloromethane, chloroethane, thionyl fluoride, thionyl chloride fluoride, phosphoryl fluoride, phosphoryl chloride fluoride, sulfuryl fluoride, sulfuryl chloride fluoride, 1-fluoropropane, 2-fluoropropane, 1,1-difluoropropane, 1,2-difluoro Examples include lopropane, 2,2-difluoropropane, 1,1,1-trifluoropropane, 1,1,2-trifluoropropane, 1,2,2-trifluoropropane, fluoroethene, cis-1,2-difluoroethene, 1,1-difluoroethene, 1-fluoropropene, propene, chlorine, chloromethane, bromine, iodine, ammonia, methylamine, dimethylamine, trimethylamine, molecular oxygen, molecular nitrogen, carbon monoxide, carbon dioxide, sulfur dioxide, methyl vinyl ether, nitrous oxide, nitrogen dioxide, nitrogen oxide, carbon disulfide, hydrogen fluoride, hydrogen chloride, methane, ethane, propane, n-butane, isobutane, cyclopropane, ethene, propene, butene, cyclobutene, acetylene, their isomers, and combinations thereof.

[0011] The salt may be based on lithium, sodium, zinc, calcium, magnesium, aluminum, or titanium.

[0012] The electrochemical apparatus may be constructed using an ion-conducting electrolyte. The apparatus may include a housing, anode, cathode, and separator layer in contact with the ion-conducting electrolyte.

[0013] Additional embodiments, substitutions, and variations that would be obvious to those skilled in the art are also disclosed herein and are particularly intended to be included as part of the present invention. The present invention is described only in the claims as granted to the Patent Office in this application or any related application, and the following summary description of a particular embodiment does not in any way limit, define, or establish the scope of legal protection.

[0014] The present invention can be better understood by referring to the following drawings. The components in the drawings are not necessarily to scale, and rather the emphasis is on clearly illustrating exemplary aspects of the invention. In the drawings, the same reference numerals indicate corresponding parts across different drawings and / or embodiments. Furthermore, various features of the different embodiments disclosed can be combined to form additional embodiments, which are part of this disclosure. To aid in a clearer explanation of the invention, it will be understood that certain components and details may not be shown in the drawings. [Brief explanation of the drawing]

[0015] [Figure 1] This figure shows the molecular structure of an olefin molecule having two, three, or four carbon atoms, as well as hydrogen, chlorine, and / or fluorine as atomic components of its molecular structure. [Figure 2] This is a graph of density functional theory calculations for determining the ionization potential and electron affinity of molecules (calculated at theoretical level 6-31+G** / B3LYP). [Figure 3] This is a graph of density functional theory calculations for determining the molecular binding energy to lithium cations (calculated at theoretical level 6-31+G** / B3LYP). [Figure 4A] This graph shows the volume retention rate and rate test results for a graphite anode half-cell using an electrolyte composed of 1M LiTFSI and 2M FEC in a MeF:ClM:CO2 45:45:10 (molar ratio). [Figure 4B]This graph shows the volume retention rate and rate test results for a graphite anode half-cell using an electrolyte composed of 1M LiTFSI and 2M FEC in a MeF:ClM:CO2 45:45:10 (molar ratio). [Figure 5A] This graph shows the capacity retention rate of a 2.7Ah cell containing a graphite anode and an NMC811 cathode, with a liquefied gas electrolyte composed of 1.0M LiFSI and 2.0M DMC in a DFE:FM:CO2:TFP 35:35:10:20 (molar ratio). [Figure 5B] This graph shows the impedance increase of a 2.7Ah cell containing a graphite anode and an NMC811 cathode, with a liquefied gas electrolyte composed of 1.0M LiFSI and 2.0M DMC in a DFE:FM:CO2:TFP 35:35:10:20 (molar ratio). [Figure 5C] This graph shows the Coulomb efficiency of a 2.7Ah cell containing a graphite anode and an NMC811 cathode, with a liquefied gas electrolyte composed of 1.0M LiFSI and 2.0M DMC in a DFE:FM:CO2:TFP molar ratio of 35:35:10:20. [Figure 6] This is a schematic diagram showing an electrochemical apparatus assembly using an integrated electrolyte. [Modes for carrying out the invention]

[0016] This specification refers to certain embodiments of the invention, including all the best modes for carrying out the invention as intended by the inventors. Examples of these specific embodiments are shown in the accompanying drawings. While the invention is described in relation to these specific embodiments, it will be understood that the invention is not intended to be limited to the embodiments described or illustrated. Rather, it is intended to include alternatives, modifications, and equivalents that may fall within the spirit and scope of the invention as defined by the accompanying claims.

[0017] In the following description, in order to provide a thorough understanding of the present invention, numerous specific details are set forth. Certain exemplary embodiments of the present invention can be implemented without some or all of these specific details. In other instances, well-known process operations have not been described in detail so as not to unnecessarily obscure the present invention. For clarity, various technologies and mechanisms of the present invention may be described in the singular. However, unless otherwise stated, it should be noted that some embodiments include multiple repetitions of a technology or multiple mechanisms. Similarly, the various steps of the methods shown and described herein need not necessarily be performed in the order shown, and in certain embodiments may not be performed at all. Thus, some examples of the methods discussed herein may include more or fewer steps than those shown or described. Further, the technologies and mechanisms of the present invention may describe a connection, relationship, or communication between two or more elements. It should be noted that a connection or relationship between elements does not necessarily mean a direct and unobstructed connection, because various other elements or processes may exist or occur between any two elements. Thus, unless otherwise stated, the connections shown do not necessarily mean direct and unobstructed connections.

[0018] The following list of exemplary features corresponds to the accompanying drawings and is provided for convenience of reference, where like reference numerals indicate corresponding features throughout the specification and drawings. Electrochemical device 5 Positive electrode / cathode 10 Separator 15 Negative electrode / anode 20 Positive terminal 25 Negative terminal 30 Housing 35 Electrolyte 40

[0019] It would be beneficial to utilize a liquefied gas solvent that has a substantially low or zero global warming potential (GWP) (GWP < 10) while maintaining other beneficial properties desired for an ideal solvent, such as high polarity, chemical stability, non-toxicity, low cost, and low flammability, and that enables the formation of a solid electrolyte interface with optimal properties on an electrode. Mixing a medium or high GWP solvent with a low or zero GWP solvent will result in a reduction of the overall GWP of the solvent composition. However, not all chemicals have all of the ideal properties necessary to create a high-performance electrolyte.

[0020] There are a number of zero or low GWP gaseous solvents, but not all of them are sufficient to maintain effective charge separation of conductive salts in an electrolyte mixture to maintain high electrolyte conductivity or have sufficient polarity to avoid phase separation within the electrolyte mixture. Examples of such low polarity, low GWP gaseous solvents include hydrocarbons such as methane, ethane, propane, and butane.

[0021] Furthermore, many gaseous solvents do not have the ideal properties or chemical makeup for forming an ideal SEI layer, and thus it is necessary to continue to use high GWP solvents in the electrolyte mixture that can be costly, flammable, and exhibit other undesirable characteristics.

[0022] Examples of low or zero GWP solvents that would impart beneficial charge separation properties, enhance electrolyte conductivity, limit phase separation, and result in a good SEI layer include 3,3,3-trifluoropropene, 2,3,3,3-tetrafluoropropene, trans-1,3,3,3-tetrafluoropropene, trans-1,1,1,4,4,4-hexafluoro-2-butene, cis-1,1,1,4,4,4-hexafluoro-2-butene, and 1,1-diph Examples include ruoroethene, 1,2-difluoroethene, 1,1-dichloroethene, vinyl chloride, vinyl fluoride, hexafluoropropene, hexafluorobutadiene, trichloroethene, dichloroethene, chlorofluoroethene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, trans-1-chloro-3,3,3-trifluoropropene, 3,3,4,4,4-pentafluoro-1-butene, and their isomers.

[0023] These low-GWP solvent mixtures have been shown to reduce the GWP of other high-GWP (or non-low-GWP) electrolyte formulations (GWP > 80). This would improve the overall environmental impact of the mixture. Some examples are shown in Table 1. When difluoromethane is used as the solvent, it shows a high GWP of 677 per kg, but a mixture of difluoromethane:1,1-difluoroethylene (1:3) would reduce this GWP to 90 per kg, or about 85% less than difluoromethane alone. In another example, fluoromethane alone has a GWP of 116, but when mixed with 2,3,3,3-tetrafluoropropene in a 1:1 molar ratio, the GWP is reduced by more than 75% to 27. Preferably, the low-GWP solvent component reduces the total GWP of the liquefied gas solvent by at least 10%, more preferably 50%, and even more preferably 70% compared to the GWP of the other solvent components in the mixture. Other potential benefits include lower vapor pressure, lower costs, extended cycle life, and improved binding energy to electrolyte cations.

[0024] [Table 1]

[0025] These solvents belong to one of several broader classes of related compounds, such as hydrofluoroolefins (HFOs), hydrochloroolefins (HCOs), hydrochlorofluoroolefins (HCFOs), perfluoroolefins (PFOs), or perchloroolefins (PCOs), which are unsaturated organic compounds composed of hydrogen, carbon, fluorine, and / or chlorine. This specification discloses the use of these hydrofluoroolefins, hydrochloroolefins, hydrochlorofluoroolefins, and / or perfluoroolefins as liquefied gaseous electrolyte components. These solvents can exhibit beneficial performance in battery cells and may be gaseous (vapor pressure greater than 100 kPa at 293.15 K) or liquid under standard conditions (vapor pressure less than 100 kPa at 293.15 K).

[0026] Further compounds that may possess properties beneficial to electrolyte and electrochemical cell performance are shown in Figure 1, where the general molecular structures are shown having an ethene, propene, or butadiene structure containing either an H, F, or Cl atom at the positions indicated by R1 to R8 on the structure.

[0027] These hydrofluoroolefins, hydrochloroolefins, hydrochlorofluoroolefins, perchloroolefins, or perfluoroolefins can be combined with other liquefied gaseous solvents to create finished solvent mixtures, and when combined with various salts and additives, they can create finished liquefied gaseous electrolytes.

[0028] Other liquefied gas solvents that can be mixed with these components include dimethyl ether, methyl ethyl ether, fluoromethane, difluoromethane, trifluoromethane, fluoroethane, tetrafluoroethane, pentafluoroethane, 1,1-difluoroethane, 1,2-difluoroethane, 1,1,1-trifluoroethane, 1,1,2-trifluoroethane, 1,1,1,2-tetrafluoroethane, 1,1,2,2-tetrafluoroethane, pentafluoroethane, chloromethane, chloroethane, thionyl fluoride, thionyl chloride fluoride, phosphoryl fluoride, phosphoryl chloride fluoride, sulfuryl fluoride, sulfuryl chloride fluoride, 1-fluoropropane, 2-fluoropropane, and 1,1-difluoropropane. Examples include 1,2-difluoropropane, 2,2-difluoropropane, 1,1,1-trifluoropropane, 1,1,2-trifluoropropane, 1,2,2-trifluoropropane, fluoroethene, cis-1,2-difluoroethene, 1,1-difluoroethene, 1-fluoropropene, propene, chlorine, chloromethane, bromine, iodine, ammonia, methylamine, dimethylamine, trimethylamine, molecular oxygen, molecular nitrogen, carbon monoxide, carbon dioxide, sulfur dioxide, methyl vinyl ether, nitrous oxide, nitrogen dioxide, nitrogen oxide, carbon disulfide, hydrogen fluoride, hydrogen chloride, methane, ethane, propane, n-butane, isobutane, cyclopropane, ethene, propene, butene, cyclobutene, acetylene, their isomers, and combinations thereof.

[0029] In some embodiments, lithium, sodium, zinc, calcium, magnesium, aluminum, or titanium-based salts are used. Furthermore, electrolytes or solvent solutions containing one or more liquefied gaseous solvents can be combined with one or more salts, such as lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium tetrachloroaluminate (LiAlCl4), lithium tetragallium aluminate, lithium bis(oxalato)borate (LiBOB), lithium hexafluorostanate (LiSnF4), lithium difluoro(oxalato)borate (LiDFOB), lithium bis(fluorosulfonyl)imide (LiFSI), lithium aluminum fluoride (LiAlF3), lithium nitrate (LiNO3), and trifluoromethanesulfone. This includes lithium oxide, lithium tetrafluoroborate (LiBF4), lithium difluorophosphate, lithium tetrafluoro(oxalato)phosphate, lithium difluorobis(oxalato)phosphate, lithium borate, lithium oxalate, lithium thiocyanate, lithium tetrachlorogallate, lithium chloride, lithium bromide, lithium iodide, lithium carbonate, lithium fluoride, lithium oxide, lithium hydroxide, lithium nitride, lithium peroxide, lithium azide, lithium delta oxide, dilithium squalate, lithium croconate dihydrate, dilithium rhozonate, dilithium ketomalonate, lithium diketosuccinate, or any corresponding salt in which a lithium cation is substituted with a positively charged sodium or magnesium cation, or any combination thereof, one or more of these.Furthermore, useful salts include positively charged cations that pair with negatively charged anions, such as acetate, bis(fluorosulfonyl)imide, bis(oxalato)borate, bis(trifluoromethanesulfonyl)imide, bromide, chloride, dicyanamide, diethylphosphate, hexafluorophosphate, bisulfate ion, iodine, methanesulfonate, methylphosphonate, tetrachloroaluminate, tetrafluoroborate, and trifluoromethanesulfonate, such as tetramethylammonium and tetraethylammonium. Ammonium, tetrapropylammonium, tetrabutylammonium, triethylmethylammonium, spiro-(1,1')-bipyrrolidinium, 1,1-dimethylpyrrolidinium and 1,1-diethylpyrrolidinium, N,N-diethyl-N-methyl-N(2-methoxyethyl)ammonium, N,N-diethyl-N-methyl-N-propylammonium, N,N-dimethyl-N-ethyl-N-(3-methoxypropyl)ammonium, N,N-dimethyl-N-ethyl-N-benzylammonium, N,N-dimethyl-N-ethyl-N-phenyl Tylammonium, N-ethyl-N,N-dimethyl-N-(2-methoxyethyl)ammonium, N-tributyl-N-methylammonium, N-trimethyl-N-hexylammonium, N-trimethyl-N-butylammonium, N-trimethyl-N-propylammonium, 1,3-dimethylimidazolium, 1-(4-sulfobutyl)-3-methylimidazolium, 1-allyl-3H-imidazolium, 1-butyl-3-methylimidazolium, 1-ethyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, 1-octyl Examples include those containing -3-methylimidazolium, 3-methyl-1-propylimidazolium, H-3-methylimidazolium, trihexyl(tetradecyl)phosphonium, N-butyl-N-methylpiperidinium, N-propyl-N-methylpiperidinium, 1-butyl-1-methylpyrrolidinium, 1-methyl-1-(2-methoxyethyl)pyrrolidinium, 1-methyl-1-(3-methoxypropyl)pyrrolidinium, 1-methyl-1-octylpyrrolidinium, 1-methyl-1-pentylpyrrolidinium, or N-methylpyrrolidinium.The alternative or additional embodiments described herein provide electrolyte compositions comprising one or more features of the foregoing description or any other description herein.

[0030] Density functional theory (DFT) can be used to determine whether a molecule is stable enough to be used as a solvent, or whether it is less stable and therefore better suited as a sacrificial additive to create an ideal solid electrolyte interface. Figure 2 shows DFT calculations for various molecules (calculated at theoretical level 6-31+G** / B3LYP). Table 2 lists some exemplary molecules with both ASHRAE and chemical nomenclature. [Table 2]

[0031] Molecules with a more positive ionization potential are more stable to oxidation, and molecules with a more negative electron affinity are more stable to reduction. Using this modeling, molecules such as R-1130(E) were determined to be relatively stable to reduction, but relatively unstable to oxidation compared to similarly modeled refrigerants. Therefore, this molecule would be useful for intentionally creating a solid electrolyte interface on the cathode. This is because, although the molecule is not expected to be reduced or decomposed at the anode surface in a battery system, the high voltage of the cathode can cause the molecule to be oxidized and decompose into various chemicals that deposit on the cathode surface. This surface layer would protect the electrolyte from further oxidation and contribute to a longer battery cell cycle life. Similarly, for other molecules, it is possible to determine whether they have good or poor oxidation or reduction stability.

[0032] The binding energy of molecules to lithium cations was also calculated using DFT. Several of the compounds shown in Figure 3 were calculated to bind well to lithium cations. This promotes salt solubility and solvation separation of anions and cations, leading to higher conductivity and better battery performance. Therefore, some ideal fluorinated, chlorinated, or fluorinated and chlorinated olefins would function as ideal solvents in electrochemical battery cell electrolytes.

[0033] It has been shown that both LiF and LiCl can act as beneficial solid electrolyte interface components. These components possess electrical resistance, ionic conductivity, and insolubility in the electrolyte solvent, which are ideal properties for solid electrolyte interfaces in batteries. Figures 4A and 4B show the use of a liquefied gas electrolyte consisting of 1M LiTFSI and 2M FEC in MeF:ClM:CO2 45:45:10 in a graphite anode half-cell. The cell was shown to have good cycle life and power performance, demonstrating the high capability of this electrolyte mixture. It is thought that a mixture of both chlorinated and fluorinated components results in an ideal SEI layer, leading to good cell performance, such as the cycle life shown in both the anode and cathode. The decomposition products of MeF and MeCl at the anode include LiF and LiCl. The good cycle characteristics of this cell indicate that LiCl can act as a good SEI forming agent. It would also be ideal to find molecules that can simultaneously produce both LiF and LiCl during decomposition. Molecules such as 2,3,3,3-tetrafluoro-1-chloropropene would promote such SEI composition. These molecules may also have other beneficial aspects, such as lower vapor pressure, lower flammability, lower cost, and lower GWP. Thus, an ideal SEI layer can be formed using a single molecule containing at least one fluorine atom, at least one chlorine atom, or at least one chlorine and fluorine atom.

[0034] Figures 5A-5C show data for R-1234ze (1,3,3,3-tetrafluoropropene), the compound shown in Figure 1, used as a component of the liquefied gas electrolyte. This electrolyte used a total electrolyte solution of 1.0 M LiFSI and 2.0 M DMC in a DFE:FM:CO2:TFP 35:35:10:20 (molar ratio). The electrolyte exhibited good performance during cycle life testing, demonstrating minimal resistance increase, high Coulomb efficiency, and low capacity degradation. Therefore, this low-pressure, low-cost, low-GWP molecule can be used in electrochemical cells, and it has been shown that successful SEI layer formation can be achieved using such hydrofluoroolefins with at least one fluorine atom, enabling stable cycling of battery cells with improved performance. The cycle stability of this cell, and the TFP properties calculated by DFT, are both consistent with the formation of a stable SEI.

[0035] Previous disclosures demonstrating the use of hydrofluoroolefins as potential candidates for use in liquefied gas electrolytes have not discussed that robust SEI layer formation can be achieved through the decomposition of solvent compounds containing both F and Cl moieties, as shown in Figure 1. Similarly, it was not recognized that hydrochloroolefins could form an ideal SEI layer containing LiCl rather than LiF. The discovery that these components can decompose to form an ideal SEI layer, and that these components can be selected based on calculated oxidation or reduction resistance for intentional solid electrolyte interface formation at the cathode or anode, is a significant discovery disclosed herein. Until now, since these molecules have not been used in electrochemical applications, it would not have been necessary to determine both their oxidation and reduction resistances. Similarly, it has been found that some of these molecules provide good binding to lithium cations, positively contributing to high electrolyte conductivity and excellent battery performance.

[0036] Furthermore, the ability of olefin-type molecules to form an ideal SEI layer through unsaturated carbon bonding was not recognized in previous disclosures. While numerous molecules with similar unsaturated carbon bonding can be added to electrolyte formulations, these often do not function well within battery cells. Olefin-type molecules are unique in that they can enable the formation of polymers containing a large number of fluorine or chlorine components (up to 8 in the molecule shown in Figure 1) during decomposition. A combination of a flexible polymer that enables SEI flexibility and adapts to electrode volume changes, and an inorganic LiF or LiCl component that enables high electrical insulation SEI, allows for high-performance, long-life cells.

[0037] The inventors also unexpectedly discovered, through repeated experiments with multiple formulations, that molecules containing chlorinated components (as opposed to fluorinated components) exhibit substantially improved solubility in various electrolyte mixtures, not only at room temperature but especially at high temperatures. This can be understood to be partly due to the lower vapor pressure of these formulations and the higher interaction energy between the molecules and salts in the electrolyte, allowing them to maintain a liquid phase under milder pressures. For each fluorine atom substituted for a chlorine atom, the pressure of these molecules decreases. This also lowers the critical point of these molecules and the electrolyte system. Lower pressures and critical points allow for a lower load on mechanical sealing, resulting in smaller cell masses and lower costs. Furthermore, the electrolyte becomes easier to handle and process.

[0038] The inventors also unexpectedly found that these compositions more readily form azeotropic mixtures, allowing the vapor and liquid phases to maintain the same compositional percentage throughout electrolyte mixing, electrolyte injection, and handling of the electrolyte during battery operation, which also contributes to reduced manufacturing costs and improved cell efficiency. One example is 1M LiTFSI and 2M FEC in a 75:25 ratio in R-1336mzz(Z):1130(E), which forms an azeotropic mixture. This mixture has a lower flammability rating due to the chlorinated molecule 1130(E) and also has a lower GWP. The improved safety and environmental performance due to these chlorinated molecules is of extremely high value and critical in the energy storage industry. Their discovery and use in liquefied gas electrolytes is undoubtedly crucial to providing the market with higher-performing, lower-cost cells.

[0039] The aforementioned liquefied gas electrolyte can be used in an electrochemical apparatus. Figure 6 is a schematic diagram of an electrochemical apparatus 5 including an electrode stack comprising a positive electrode 25, a negative electrode 20, and an ionic conductive but electrically insulating separator membrane 15. The stack is immersed in an electrolyte mixture 40. The electrode stack and electrolyte 40 are also housed inside a battery housing 35, with the positive terminal 25 and negative terminal 30 accessible from outside the housing 35. The battery cell housing 35 is structured to maintain the pressure necessary to ensure that the liquefied gas electrolyte remains in the liquid phase under pressure.

[0040] While this document includes many specific examples, these should not be interpreted as limitations on the scope of any invention or claimed scope, but rather as descriptions of features that may be specific to a particular embodiment of a particular invention. Certain features described in this patent document in the context of a separate embodiment may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately or in any preferred subcombination in multiple embodiments. Furthermore, features may be described above as acting in a particular combination, and may even be initially claimed in this manner, but one or more features from a claimed combination may be removed from the combination in some cases, and the claimed combination may cover a subcombination or a variation of a subcombination.

Claims

1. salt; and A liquefied gas solvent mixture comprising a first solvent component and a second solvent component, having a vapor pressure exceeding 100 kPa at a temperature of 293.15 K, wherein the first solvent component is selected from the group consisting of hydrochloroolefin, hydrochlorofluoroolefin, perchloroolefin, and perfluoroolefin. Ion-conducting electrolytes, including [specific component].

2. The ion-conducting electrolyte according to claim 1, wherein the relative amounts of the first solvent component and the second solvent component are selected to reduce the global warming potential (GWP) of the liquefied gas solvent mixture to less than 10% of the GWP of the second solvent component alone.

3. The ion-conducting electrolyte according to claim 1, wherein the relative amounts of the first solvent component and the second solvent component are selected to reduce the global warming potential (GWP) of the liquefied gas solvent mixture to less than 50% of the GWP of the second solvent component alone.

4. The ion-conducting electrolyte according to claim 1, wherein the relative amounts of the first solvent component and the second solvent component are selected to reduce the global warming potential (GWP) of the liquefied gas solvent mixture to less than 70% of the GWP of the second solvent component alone.

5. The ion-conducting electrolyte according to any one of claims 1 to 4, wherein the first solvent component has a global warming potential (GWP) of less than 10.

6. The ion-conducting electrolyte according to claim 5, wherein the second solvent component has a GWP of more than 80.

7. The ion-conducting electrolyte according to any one of claims 1 to 6, wherein the first solvent component is selected from the group consisting of 1,1-dichloroethene, vinyl chloride, trichloroethene, dichloroethene, chlorofluoroethene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, trans-1-chloro-3,3,3-trifluoropropene, and isomers thereof.

8. The second solvent component is dimethyl ether, methyl ethyl ether, fluoromethane, difluoromethane, trifluoromethane, fluoroethane, tetrafluoroethane, pentafluoroethane, 1,1-difluoroethane, 1,2-difluoroethane, 1,1,1-trifluoroethane, 1,1,2-trifluoroethane, 1,1,1,2-tetrafluoroethane, 1,1,2,2-tetrafluoroethane, pentafluoroethane, chloromethane, chloroethane, thionyl fluoride, thionyl chloride fluoride, phosphoryl fluoride, phosphoryl chloride fluoride, sulfuryl fluoride, sulfuryl chloride fluoride, 1-fluoropropane, 2-fluoropropane, 1,1-difluoropropane, 1,2-difluoropropane, 2,2-difluoropropane An ion-conducting electrolyte according to any one of claims 1 to 7, selected from the group consisting of n, 1,1,1-trifluoropropane, 1,1,2-trifluoropropane, 1,2,2-trifluoropropane, fluoroethene, cis-1,2-difluoroethene, 1,1-difluoroethene, 1-fluoropropene, propene, chlorine, chloromethane, bromine, iodine, ammonia, methylamine, dimethylamine, trimethylamine, molecular oxygen, molecular nitrogen, carbon monoxide, carbon dioxide, sulfur dioxide, methyl vinyl ether, nitrous oxide, nitrogen dioxide, nitrogen oxide, carbon disulfide, hydrogen fluoride, hydrogen chloride, methane, ethane, propane, n-butane, isobutane, cyclopropane, ethene, propene, butene, cyclobutene, acetylene, isomers thereof, and combinations thereof.

9. The ion-conducting electrolyte according to any one of claims 1 to 8, wherein the salt is based on lithium, sodium, zinc, calcium, magnesium, aluminum, or titanium.

10. An electrochemical apparatus comprising the electrolytes of claims 1 to 9.

11. A housing for containing the ion-conducting electrolyte; Anode, cathode, and separator layers in contact with the ion-conducting electrolyte. The electrochemical apparatus according to claim 10, further comprising:

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