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US-12620595-B2 - Increased capacity battery cell using reservoir replenishing additives

US12620595B2US 12620595 B2US12620595 B2US 12620595B2US-12620595-B2

Abstract

The use of reservoir replenishing additives to an electrochemical cell in conjunction with a liquefied gas electrolyte is described to maintain high capacity and high energy of a battery cell.

Inventors

  • Cyrus S. Rustomji
  • Frederick Krause

Assignees

  • SOUTH 8 TECHNOLOGIES, INC.

Dates

Publication Date
20260505
Application Date
20250813

Claims (8)

  1. 1 . A method of forming an electrochemical cell comprising a cathode that includes a reservoir-replenishing additive and a liquefied-gas electrolyte, the method comprising: during formation, charging the electrochemical cell to a voltage sufficient to oxidize at least a portion of the additive while maintaining a pressure increase of ≤10% relative to pre-charge pressure at 293.15 K.
  2. 2 . The method of claim 1 , further comprising holding at 4.3-4.5 V for ≤60 min at 30-50° C. to complete oxidation of Li 2 CO 3 .
  3. 3 . An electrochemical cell comprising: a housing configured to maintain an internal pressure of at least 100 kPa at 293.15 K; an anode; a cathode comprising a cathode active material and 0.1-10 wt % of a reservoir-replenishing additive selected from Li 2 CO 3 , Li 3 N, Li 2 O, Li 2 O 2 , or LiOH; and a liquefied-gas electrolyte comprising a liquefied-gas solvent and a lithium salt; wherein, during an initial charge, the reservoir-replenishing additive oxidizes to release Li + and a gaseous species selected from CO 2 , N 2 , or O 2 , the gaseous species dissolving in the liquefied-gas electrolyte without bubble formation, and a pressure increase is ≤10% relative to a pre-charge pressure measured at 293.15 K.
  4. 4 . The electrochemical device of claim 3 , wherein sufficient reservoir-replenishing additive is added to the cathode to replenish above 1% of the electrochemical device capacity.
  5. 5 . The electrochemical device of claim 3 , wherein the electrochemical device exhibits a first-cycle coulombic efficiency ≥92%.
  6. 6 . The electrochemical device of claim 3 , wherein the oxidation of the reservoir-replenishing additive occurs at a cathode potential of 3.8-4.6 V vs. Li/Li + .
  7. 7 . The electrochemical device of claim 3 , wherein the liquefied gas electrolyte comprises one or more of 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, 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, methyl amine, dimethyl amine, trimethyl amine, 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, 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, 1,1-difluoroethene, 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, hydrofluoroolefins (HFOs), hydrochloroolefins (HCOs), hydrochlorofluoroolefins (HCFOs), perfluoroolefins (PFOs), or perchloroolefins (PCOs), methane, ethane, propane, n-butane, iso-butane, cyclopropane, cyclopropane, ethene, propene, butene, cyclobutane, cyclobutene, acetylene, pentane, hexane, heptane, octane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, isomers thereof, or a combination thereof; and wherein the salt comprises one or more of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF 6 ), lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium tetrachloroaluminate (LiAlCl 4 ), lithium tetragalliumaluminate, lithium bis(oxalato)borate (LiBOB), lithium hexafluorostannate (LiSnF 4 ), lithium difluoro(oxalato)borate (LiDFOB), lithium bis(fluorosulfonyl)imide (LiFSI), lithium aluminum fluoride (LiAlF 3 ), lithium nitrate (LiNO 3 ), lithium trifluoromethanesulfonate, lithium tetrafluoroborate (LiBF 4 ), 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 superoxide, lithium azide, lithium deltate, dilithium squarate, lithium croconate dihydrate, dilithium rhodizonate, lithium ketomalonate, lithium diketosuccinate or any corresponding salts with a positively charged sodium or magnesium cation substituted for the lithium cation, or any combinations thereof, tetramethylammonium, tetraethylammonium, 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-phenylethylammonium, 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-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 paired with negatively charged anions such as acetate, bis(fluorosulfonyl)imide, bis(oxalato)borate, bis(trifluoromethanesulfonyl)imide, bromide, chloride, dicyanamide, diethyl phosphate, hexafluorophosphate, hydrogen sulfate, iodide, methanesulfonate, methyl-phophonate, tetrachloroaluminate, tetrafluoroborate, or trifluoromethanesulfonate.
  8. 8 . The electrochemical device of claim 3 , wherein the liquefied gas electrolyte further comprises one or more additives selected from dimethyl carbonate, ethyl methyl carbonate, propyl methyl carbonate, butyl methyl carbonate, diethyl carbonate, propyl ethyl carbonate, butyl ethyl carbonate, dipropyl carbonate, propyl butyl carbonate, dibutyl carbonate, fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis(fluoromethyl)carbonate, bis(difluoromethyl)carbonate, bis(trifluoromethyl)carbonate, fluoromethyl ethyl carbonate, difluoromethyl ethyl carbonate, trifluoromethyl ethyl carbonate, fluoroethyl ethyl carbonate, difluoroethyl ethyl carbonate, trifluoroethyl ethyl carbonate, tetrafluoroethyl ethyl carbonate, pentafluoroethyl ethyl carbonate, hexafluoroethyl ethyl carbonate, bis(fluoroethyl)carbonate, bis(difluoroethyl)carbonate, bis(trifluoroethyl) carbonate, bis(tetrafluoroethyl)carbonate, bis(pentafluoroethyl)carbonate, bis(hexafluoroethyl)carbonate, vinyl carbonate, ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, trans-butylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate, trifluoroethylene carbonate, tetrafluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, trichloroethylene carbonate, tetrachloroethylene carbonate, fluoromethyl ethylene carbonate, difluoromethyl ethylene carbonate, trifluoromethyl ethylene carbonate, bis(fluoromethyl)ethylene carbonate, bis(difluoromethyl)ethylene carbonate, bis(trifluoromethyl)ethylene carbonate, methyl propyl ether, methyl butyl ether, diethyl ether, ethyl propyl ether, ethyl butyl ether, dipropyl ether, propyl butyl ether, dibutyl ether, ethyl vinyl ether, divinyl ether, glyme, diglyme, triglyme, tetraglyme, 1,1,2,2-Tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)-propane, trifluoro(trifluoromethoxy)methane, perfluoroethyl ether, fluoromethyl methyl ether, difluoromethyl methyl ether, trifluoromethyl methyl ether, bis(fluoromethyl)ether, bis(difluoromethyl)ether, fluoroethyl methyl ether, difluoroethyl methyl ether, trifluoroethyl methyl ether, bis(fluoroethyl)ether, bis(difluoroethyl)ether, bis(trifluoroethyl)ether, 2-fluoroethoxymethoxyethane, 2,2 difluoroethoxymethoxyethane, methoxy-2,2,2-trifluoroethoxyethane, ethoxy-2-fluoroethoxyethane, 2,2-difluoroethoxyethoxyethane, ethoxy-2,2,2-trifluoroethoxyethane, methyl nanofluorobutyl ether, ethyl nanofluorobutyl ether, 2 fluoroethoxymethoxyethane, 2,2-difluoroethoxymethoxyethane, methoxy 2,2,2 trifluoroethoxyethane, ethoxy-2-fluoroethoxyethane, 2,2-difluoroethoxyethoxyethane, ethoxy 2,2,2-trifluoroethoxyethane, bis(trifluoro) methyl ether, dimethylether, methyl ethyl ether, methyl vinyl ether, perfluoromethyl-vinylether, propylene oxide, tetrahydrofuran, tetrahydropyran, furan, 12-crown-4, 12-crown-5, 18-crown-6, 2-Methyltetrahydrofuran, 1,3-Dioxolane, 1,4-dioxolane, 2-methyloxolane, (1,2-propylene oxide), ethylene oxide, octafluorotetrahydrofuran, acetonitrile, propionitrile, butanenitrile, pentanenitrile, hexanenitrile, hexanedinitrile, pentanedinitrile, butanedinitrile, propanedinitrile, ethanedinitrile, isovaleronitrile, benzonitrile, phenylacetonitrile, cyanogen chloride, hydrogen cyanide, ethanedinitrile, trimethylphosphate, triethylphosphate, isomers thereof, or any combination thereof.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority from U.S. Provisional Application Ser. No. 63/684,297 filed on Aug. 16, 2024, which is incorporated herein by reference in its entirety. TECHNICAL FIELD This disclosure relates to the addition of chemical compounds to the battery cathode which may be oxidized during a first charge of the battery cell, thereby releasing oxidation products composed of a cation and a normally gaseous compound at standard temperature and pressure. The release of the cation can improve the capacity of the cell while the released gaseous compound may solubilize into the electrolyte solution. BACKGROUND Battery cells are often composed of an anode, a cathode, a separator, and a battery electrolyte. Most commonly, such as in lithium-ion batteries, the first charge cycle, commonly known as a formation cycle, will consume lithium cations via electrochemical reactions that build a solid electrolyte interphase (SEI) on the anode or cathode. Most frequently, these cations are consumed from the cathode, which serves as the lithium reservoir of the cell. The consumption of the lithium cations to form the SEI reduces the total capacity of the cell, because those cations consumed by the SEI are no longer mobile and cannot participate in the electrochemical charge and discharge processes. There is a need to increase the overall capacity of the cell to increase energy, reduce cost, reduce mass, and improve efficiency. SUMMARY Disclosed herein is a description of chemical additives, or reservoir replenishing additives, to the cathode of an electrochemical cell comprising a liquefied gas electrolyte, which, upon oxidation, may release oxidation products composed of a cation and a normally gaseous compound. The release of the cation can improve the capacity of the cell while the released gaseous compound may solubilize into the electrolyte solution. The additional cations released into the cell will improve cell capacity via replenishing the lithium consumed through the formation of the SEI. The additional oxidation products can be composed of chemical compounds which are normally gaseous under atmospheric pressure and at a room temperature. However, with the use of a liquefied gas electrolyte, these normally gaseous compounds may be solubilized into the liquefied gas electrolyte and not appreciably increase the pressure of the cell. Using an ordinary liquid-based electrolyte, the oxidation of these chemical compounds would increase the pressure of the battery cell to unmanageable pressures which could lead to cell failure. The oxidation of these compounds can lead to gaseous materials that form bubbles, reducing wettability of the electrodes and increasing impedance of the cell and decreasing capacity. In certain cases, the resultant pressures could be so high that the vent on the cell may open and potentially cause electrical disconnect or ingress of atmospheric components leading to early cell failure. However, with a liquefied gas electrolyte, the cell is designed to withstand these pressures. Furthermore, a cell using a liquefied gas electrolyte is normally operating under an increased pressure, thus any release of gas inside the cell from these additives would cause only a modest increase in pressure relative to the nominal pressure of the electrolyte. If a cell using a liquid-based electrolyte were designed to withstand the increased pressures, the generation of gaseous compounds would not readily liquefy at the nominal pressure of a liquid electrolyte, which would lead to bubble formation, dry-out of the electrodes, and subsequent cell failure. Such chemical compounds which can be added to the cathode could be Li2CO3, LiHCO3, Li3N, Li2O, Li2O2, or LiOH. In other aspects of the disclosed technology, the lithium in these compounds is replaced by another cation such as sodium, potassium, calcium, aluminum, zinc, magnesium, or others for similar benefits in a sodium, potassium, calcium, aluminum, zinc, or magnesium type battery device. These compounds can be oxidized to release lithium and compounds which are gaseous under standard conditions (293.15 K and 1 atmosphere of pressure) such as CO2, N2, or O2. These gaseous compounds could readily be solubilized into the liquefied gas electrolyte, resulting in only a moderate pressure increase of the cell and generating no dry spots within the cell, allowing for continued optimal cycling conditions with no impedance increase or capacity decrease. In a lithium-ion cell, normal SEI formation during the first charge cycle can result in loss of lithium inventory, as high as 20%, but typically closer to 10% or 5%. Thus, if the cell contained additional chemical compounds which could replenish lithium inventory by the same amount, such as 1%, 2%, 4%, 8%, 12%, 16%, or 20%, then the cell would result in having a higher capacity, resulting in higher energy. Of course, the similar invention may be used in a variety of cell chemistries