Functionalized crown ethers for lithium ion batteries

Abstract

An electrolyte containing functionalized crown ethers suitable for use in electrochemical energy storage devices is disclosed, which can be used to reduce battery resistance, increase cycle life, and improve high temperature performance.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 392,025, filed on July 25, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to functionalized crown ethers that can be used to reduce battery resistance, increase cycle life, and improve high-temperature performance; electrolytes containing the functionalized crown ethers; and electrochemical energy storage devices utilizing the electrolytes. Background Technology

[0004] Lithium-ion batteries are widely used in consumer electronics, electric vehicles (EVs), energy storage systems (ESS), and smart grids. Recently, lithium-ion batteries with voltages above 4.35V have gained importance due to their higher capacity and subsequent energy density benefits. However, the stability of cathode (or positive electrode) materials at these potentials decreases due to increased oxidation. This can lead to electrochemical oxidation of the material, generating gases that can degrade battery performance. Cathode active materials capable of intercalating / deintercalating lithium ions may dissolve in non-aqueous electrolytes, causing structural damage and increasing interfacial resistance. These lithium-ion batteries are also typically exposed to extreme temperatures during operation. The SEI (solid electrolyte interphase) layer formed on the anode (or negative electrode) gradually decomposes at high temperatures, leading to more irreversible reactions and capacity loss. Similarly, the CEI (cathode electrolyte interphase) also loses stability at high temperatures. These reactions occur at both the positive and negative electrodes during cycling, but are generally more severe at higher temperatures due to faster kinetics. Compared to the most advanced lithium-ion batteries currently available, the next generation of lithium-ion batteries for consumer electronics, EVs, and ESS will require significant improvements in electrolyte composition.

[0005] The primary role of electrolytes is the transport of positive and negative ions between battery electrodes. Historically, researchers have focused on developing battery electrodes, while electrolyte development has been limited. Traditional lithium-ion batteries use carbonate-based electrolytes with large electrochemical windows, capable of transporting lithium ions. These electrolytes require functional additives for passivating the anode and forming a stable SEI, as well as additives for stabilizing the cathode. Simultaneously, additives need to be designed and developed to allow for stable and safe cycling of high-voltage, high-energy lithium-ion batteries.

[0006] As the industry moves towards higher energy cathode materials for higher energy batteries, stable, efficient and safe cycling of the battery in a wide voltage window is necessary. Lithium ion battery electrolytes can be tuned based on their application by the addition of different co-solvents and additives. This tunability enables the development of different additives for high voltage stability and safety of lithium ion batteries.

[0007] Crown ethers have been reported in the literature as additives that can coordinate with metal ions, which can have a wide range of beneficial effects ranging from improving lithium solvation, reducing charge transfer resistance, scavenging dissolved manganese ions from the cathode (Ochida, M.; Doi, T.; Domi, Y.; Tsubouchi, S.; Nakagawa, H.; Yamanaka, T.; Abe, T.; Ogumi, Z. J. Electrochem. Soc. 2013, 160, A410, Xu, K. Chem. Rev. 2004, 104, 4303). Japanese patent JP2000195548A has reported the use of crown ethers and azacrown ethers as components of lithium secondary battery electrolytes. US Patent No. 9,130,231 has reported the use of crown ethers as components in microporous separators for lithium ion batteries. Chinese patent CN103613576 has reported the synthesis of macrocyclic cyclic sulfates.

[0008] In this document, functionalized crown ethers are reported as additives for lithium ion batteries. These molecules allow for the stabilization of the cathode and the overall electrolyte system when added to the electrolyte. Batteries containing this additive in the electrolyte will be able to achieve safe, long cycle life and high energy lithium ion batteries. Therefore, there is a need to incorporate these novel additives to improve the performance of lithium ion batteries. SUMMARY

[0009] According to one aspect of the disclosure, a class of novel compounds and electrolytes for electrochemical energy storage devices is provided. The electrolyte includes: a functionalized crown ether; an aprotic organic solvent; and a metal salt.

[0010] According to another aspect of the disclosure, an electrolyte for electrochemical energy storage devices is provided, the electrolyte including: a functionalized crown ether; an aprotic organic solvent; a metal salt; and at least one additive.

[0011] According to another aspect of the disclosure, an electrochemical energy storage device is provided, including: a cathode; an anode; a separator; and an electrolyte including a functionalized crown ether, an aprotic organic solvent, and a metal salt.

[0012] According to another aspect of the disclosure, there is provided an electrolyte for an electrochemical energy storage device, the electrolyte comprising: a functionalized crown ether; an aprotic organic solvent; a metal salt; and at least one additive; wherein the aprotic organic solvent comprises a linear or cyclic carbonate, a carboxylic acid ester, a nitrite, an ether, a sulfone, a sulfoxide, a ketone, a lactone, a dioxolane, a glyme, a crown ether, a siloxane, a phosphate ester, a phosphite ester, a monophosphazene or a polyphosphazene, or a mixture thereof.

[0013] According to another aspect of the disclosure, there is provided an electrolyte for an electrochemical energy storage device, the electrolyte comprising: a functionalized crown ether; an aprotic organic solvent; a metal salt; and at least one additive; wherein the cation of the metal salt is aluminum, magnesium, or an alkali metal such as lithium or sodium.

[0014] According to another aspect of the disclosure, there is provided an electrolyte for an electrochemical energy storage device, the electrolyte comprising: a functionalized crown ether; an aprotic organic solvent; a metal salt; and at least one additive; wherein the additive comprises a compound containing at least one unsaturated carbon-carbon bond, a carboxylic anhydride, a sulfur-containing compound, a phosphorus-containing compound, a boron-containing compound, a silicon-containing compound, or a mixture thereof.

[0015] These and other aspects of the disclosure will become apparent upon reading the following detailed description and upon examining the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 differential capacity curves of battery formation of dQ / dV curves of electrolytes tested in NMC622 / Gr batteries;

[0017] Figure 2 room temperature cycle life characteristics in cycle life plots of electrolytes tested in NMC622 / Gr batteries;

[0018] Figure 3 differential capacity curves of battery formation of dQ / dV curves of electrolytes tested in NMC811 / SiO+Gr batteries; and

[0019] Figure 4 room temperature cycle life characteristics in cycle life plots of electrolytes tested in NMC811 / SiO+Gr batteries. DETAILED DESCRIPTION

[0020] The disclosed technology relates generally to lithium ion (Li-ion) battery electrolytes. In particular, the disclosure relates to functionalized crown ethers comprising at least one oxygen-phosphorus bond or at least one oxygen-sulfur bond; electrolytes containing these functionalized crown ether materials; and electrochemical energy storage devices containing these electrolytes.

[0021] The present disclosure describes lithium-ion battery electrolytes with electrolyte formulations that can overcome cathode stability challenges in lithium-ion batteries, particularly those that include cathode materials with high nickel content at high voltage. The most advanced lithium-ion batteries currently include either cathode materials with low nickel content and operating at high voltage, or cathode materials with high nickel content but operating at low voltage. The most advanced electrolytes are tuned for these cases, and researchers have recently begun to focus on using novel electrolyte formulations to enable high-nickel, high-voltage battery cathodes. There is a need to develop an electrolyte solution for cycling lithium-ion batteries with high-voltage, high-nickel cathodes. The present technology is based on an innovative functionalized crown ether that, when incorporated into an electrolyte, can improve the stability of high-voltage, high-energy cathodes. When used at low weight loadings, the electrolyte ether forms a unique cathode electrolyte interface (CEI) and does not overpassivate the cathode. In addition, the improved CEI improves high-temperature performance and storage stability with no impact at room temperature.

[0022] In embodiments, the electrochemical energy storage device electrolyte includes a) an aprotic organic solvent; b) a metal salt; c) a functionalized crown ether compound material. In embodiments, the functionalized crown ether compound material is present at a concentration of 0.01 wt% to 10 wt% of the electrolyte.

[0023] In aspects of the present disclosure, the molecular structure of at least one functionalized crown ether organic compound according to Formula I, II, or III is

[0024]

[0025] wherein:

[0026] n is an integer in the range of 1 to 8;

[0027] X is independently oxygen or sulfur; and

[0028] R is independently further bonded to a C1-C 12 substituted or unsubstituted alkyl group or C6-C 14 halogen, oxygen, or sulfur atom of an aryl group,

[0029] wherein any hydrogen atom can be replaced (or alternatively, substituted) with an epoxide, halogen, alkyl, alkoxy, perfluoroalkyl, silyl, siloxy, silane, sulfoxide, amide, azo, ether, and thioether group, or combinations thereof, or a carbon atom can be unsubstituted or can be substituted with an epoxide, halogen, alkyl, alkoxy, perfluoroalkyl, silyl, siloxy, silane, sulfoxide, amide, azo, ether, and thioether group, or combinations thereof.

[0030] Particular examples of molecules according to the present disclosure are as listed below:

[0031]

[0032]

[0033] These examples are merely illustrative and are not intended to limit the disclosure of the appended claims.

[0034] The addition of functionalized crown ethers to lithium ion battery systems allows for the sequestration of metal ions and stabilization of the cathode surface. The resulting effect inhibits further oxidative decomposition of the remaining electrolyte components that would otherwise occur upon contact with the cathode material. The inclusion of phosphorus-oxygen bonds can ensure good coordination with high-nickel, high-energy cathode materials.

[0035] The present disclosure also includes methods for synthesizing functionalized crown ethers, as well as the use of such molecules in lithium ion battery electrolytes. These molecules impart greater stability to electrolytes and cathodes that operate at higher potentials.

[0036] In aspects of the present disclosure, the electrolyte includes a metal salt. In embodiments, the metal salt is present in the electrolyte in a range of 10 wt% to 30 wt%. In embodiments, the cation of the metal salt is aluminum, magnesium, or an alkali metal such as lithium or sodium. A variety of lithium salts can be used, including, for example, Li(AsF6); Li(PF6); Li(CF3CO2); Li(C2F5CO2); Li(CF3SO3); Li[N(CF3SO2)2]; Li[C(CF3SO2)3]; Li[N(SO2C2F5)2]; Li(ClO4); Li(BF4); Li(PO2F2); Li[PF2(C2O4)2]; Li[PF4C2O4]; lithium alkylfluorophosphates; Li[B(C2O4)2]; Li[BF2C2O4]; Li2[B 12 Z 12-j H j ] ; Li2[B 10 X 10-j’ H j’ ] ; or a mixture of any two or more thereof, wherein Z is independently at each occurrence halogen, j is an integer from 0 to 12 and j’ is an integer from 1 to 10.

[0037] In aspects of the present disclosure, the electrolyte includes an aprotic organic solvent selected from an open-chain or cyclic carbonate, a carboxylate, a nitrite, an ether, a sulfone, a sulfoxide, a ketone, a lactone, a dioxolane, a glymes, a crown ether, a siloxane, a phosphate, a phosphite, a monophosphonite, or a polyphosphonite, or a mixture thereof. In embodiments, the solvent is present in the electrolyte in a range of 50 wt% to 90 wt%.

[0038] Examples of aprotic solvents for producing electrolytes include, but are not limited to, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, dipropyl carbonate, propylene carbonate, ethylene carbonate, fluoroethylene carbonate, bis(trifluoroethyl) carbonate, bis(pentafluoropropyl) carbonate, methyl trifluoroethyl carbonate, methyl pentafluoroethyl carbonate, methyl heptafluoropropyl carbonate, methyl perfluorobutyl carbonate, ethyl trifluoroethyl carbonate, ethyl pentafluoroethyl carbonate, ethyl heptafluoropropyl carbonate, ethyl perfluorobutyl carbonate, etc., fluorinated oligomers, methyl propionate, ethyl propionate, butyl propionate, dimethoxyethane, triglyme, tetraglyme, dimethyl ether, polyethylene glycol, triphenyl phosphate, tributyl phosphate, hexafluorocyclotriphosphazene, 2-ethoxy-2,4,4,6,6-pentafluoro-1,3,5,2-5,4-5,6-5 triazatriphosphinine, triphenyl phosphite, sulfolane, dimethyl sulfoxide, methyl ethyl sulfone, ethyl vinyl sulfone, allyl methyl sulfone, diethyl vinyl sulfone, fluorophenyl methyl sulfone, and gamma-butyrolactone.

[0039] In aspects of the present disclosure, the electrolyte further includes at least one additive to protect the electrode and electrolyte from degradation. Thus, the electrolyte of the present technology can include an additive that is reduced or polymerized on the surface of the electrode to form a passivation film on the surface of the electrode.

[0040] In embodiments, the additive is a substituted or unsubstituted linear, branched, or cyclic hydrocarbon that includes at least one oxygen atom and at least one aryl, alkenyl, or alkynyl group. The passivation film formed from such an additive can also be formed from a substituted aryl compound or a substituted or unsubstituted heteroaryl compound, where the additive includes at least one oxygen atom.

[0041] Representative additives include glyoxal bis(diallyl acetal), tetra(ethylene glycol) divinyl ether, 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane, 2,4,6-triallyloxy-1,3,5-triazine, 1,3,5-triacryloylhexahydro-1,3,5-triazine, 1,2-divinyl furoate, 1,3-butadiene carbonate, 1- vinyl azetidin-2-one, 1-vinyl aziridin-2-one, 1-vinyl piperidin-2-one, 1-vinyl pyrrolidin-2-one, 2,4-divinyl-1,3-dioxane, 2-amino-3-vinyl cyclohexanone, 2-amino-3-vinyl cyclopropanone, 2-amino-4-vinyl cyclobutanone, 2-amino-5-vinyl cyclopentanone, 2-aryloxy-cyclopropanone, 2-vinyl-[1,2]oxazetidine, 2-vinylamino cyclohexanol, 2-vinylamino cyclopropanone, 2-vinyloxetane, 2-vinyloxy-cyclopropanone, 3-(N-vinylamino)cyclohexanone, 3,5-divinyl furoate, 3-vinyl azetidin-2-one, 3-vinyl aziridin-2-one, 3-vinyl cyclobutanone, 3-vinyl cyclopentanone, 3-vinyl oxaziridine, 3-vinyl oxetane, 3-vinyl pyrrolidin-2-one, 2-vinyl-1,3-dioxolane, acrolein diethyl acetal, acrolein dimethyl acetal, 4,4-divinyl-3-dioxolan-2-one, 4-vinyl tetrahydropyran, 5-vinyl piperidin-3-one, allyl glycidyl ether, butadiene monoxide, butyl vinyl ether, dihydropyran-3-one, divinyl butyl carbonate, divinyl carbonate, divinyl crotonate, divinyl ether, divinyl ethylene carbonate, divinyl ethylene silicate, divinyl ethylene sulfate, divinyl ethylene sulfite, divinyl methoxypyrazine, divinyl methyl phosphate, divinyl propylene carbonate, ethyl phosphate, methoxy-o-terphenyl, methyl phosphate, oxetan-2-yl-vinyl amine, oxiranyl vinyl amine, vinyl carbonate, vinyl crotonate, vinyl cyclopentanone, vinyl ethyl-2-furoate, vinyl ethylene carbonate, vinyl ethylene silicate, vinyl ethylene sulfate, vinyl ethylene sulfite, vinyl methacrylate, vinyl phosphate, vinyl-2-furoate, vinyl cyclopropanone, vinyl oxirane, β-vinyl-γ-butyrolactone, or a mixture of any two or more thereof.In some embodiments, the additive can be a cyclotriphosphazene substituted with F, alkoxy, alkenyloxy, aryloxy, methoxy, allyloxy groups, sulfonic acid groups, or a combination thereof. For example, the additive can be a (divinyl)-(methoxy)(trifluoro) cyclotriphosphazene, (tri-vinyl)(difluoro)(methoxy) cyclotriphosphazene, (vinyl)(methoxy)(tetrafluoro) cyclotriphosphazene, (aryloxy)(tetrafluoro)(methoxy) cyclotriphosphazene, (methylsulfonyl) cyclotriphosphazene, or (di-aryloxy)(trifluoro)(methoxy) cyclotriphosphazene compound or a mixture of two or more such compounds.

[0042] In some embodiments, the additive is a sulfur-containing compound, a phosphorus- containing compound, a boron-containing compound, a silicon-containing compound, a fluorine- containing compound, a nitrogen-containing compound, a compound containing at least one unsaturated carbon-carbon bond, a carboxylic anhydride, or a mixture thereof. In some embodiments, the additive is ethylene carbonate, vinyl ethylene carbonate, or a mixture of any two or more such compounds. Further, the additive is present in a range of 0.01 wt% to 10 wt%.

[0043] In some embodiments, the additive is a fully or partially halogenated phosphonate compound, an ionic liquid, or a mixture thereof. The halogenated phosphonate can include 4-fluorophenyl diphenyl phosphate, 3,5-difluorophenyl diphenyl phosphate, 4-chlorophenyl diphenyl phosphate, trifluorophenyl phosphate, heptafluorobutyl diphenyl phosphate, trifluoroethyl diphenyl phosphate, bis(trifluoroethyl)phenyl phosphate, and phenyl bis(trifluoroethyl) phosphate. The ionic liquid can include tris(N-ethyl-N-methylpyrrolidinium) thiophosphate bis(trifluoromethylsulfonyl) imide, tris(N-ethyl-N-methylpyrrolidinium) phosphate bis(trifluoromethylsulfonyl) imide, tris(N-ethyl-N-methylpiperidinium) thiophosphate bis(trifluoromethylsulfonyl) imide, tris(N-ethyl-N-methylpiperidinium) phosphate bis(trifluoromethylsulfonyl) imide, N-methyl-trimethylsilylpyrrolidinium bis(trifluoromethylsulfonyl) imide, N-methyl-trimethylsilylpyrrolidinium hexafluorophosphate. Further, the additive is present in a range of 0.01 wt% to 10 wt%.

[0044] In an embodiment, the electrochemical energy storage device is a lithium secondary battery. In some embodiments, the secondary battery is a lithium battery, a lithium ion battery, a lithium sulfur battery, a lithium air battery, a sodium ion battery, or a magnesium battery. In some embodiments, the electrochemical energy storage device is an electrochemical cell, such as a capacitor. In some embodiments, the capacitor is an asymmetric capacitor or a supercapacitor. In some embodiments, the electrochemical cell is a primary battery. In some embodiments, the primary battery is a lithium / MnO2 battery or a Li / poly(unicarbon fluoride) battery.

[0045] In embodiments, a secondary battery is provided that includes a positive electrode and a negative electrode separated from each other using a porous separator and an electrolyte described herein.

[0046] Suitable cathode materials for a secondary battery including an electrolyte described herein include those materials such as, but not limited to, vanadium oxide, lithium peroxide, sulfur, polysulfides, lithium unifluoride (also known as LiCF x ) or mixtures of any two or more thereof, carbon-coated olivine cathodes (such as LiFePO4), lithium metal oxides (such as LiCoO2, LiNiO2, LiNi x Co y Met z O2, LiMn 0.5 Ni 0.5 O2, LiMn 0.1 Co 0.1 Ni 0.8 O2, LiMn 0.2 Co 0.2 Ni 0.6 O2, LiMn 0.3 Co 0.2 Ni 0.5 O2, LiMn 0.33 Co 0.33 Ni 0.33 O2, LiMn2O4, LiFeO2, Li 1+x' Ni α Mn β Co γ Met' δ O 2-z' F z' ) or A n'B2(X04)3, where Met is Al, Mg, Ti, B, Ga, Si, Mn, or Co; Met' is Mg, Zn, Al, Ga, B, Zr, or Ti; A is Li, Ag, Cu, Na, Mn, Fe, Co, Ni, Cu, or Zn; B is Ti, V, Cr, Fe, or Zr; X is P, S, Si, W, or Mo; and where 0≤x≤0.3, 0≤y≤0.5, 0≤z≤0.5, 0≤x'≤0.4, 0≤a≤l, 0≤β≤l, 0≤γ≤l, 0≤δ≤0.4, 0≤z'≤0.4, and 0≤n'≤3. In other embodiments, the olivine cathode has the formula Li 1+x Fe 1z Met" y PO 4-m X' n where Met" is Al, Mg, Ti, B, Ga, Si, Ni, Mn, or Co; X' is S or F; and where 0≤x≤0.3, 0≤y≤0.5, 0≤z≤0.5, 0≤m≤0.5, and 0≤n≤0.5.

[0047] Suitable anodes include those materials such as lithium metal, graphite materials, amorphous carbon, carbon nanotubes, Li4Ti50i2 12 , tin alloys, silicon, silicon alloys, intermetallic compounds, or mixtures of any two or more such materials. Suitable graphite materials include natural graphite, artificial graphite, mesocarbon microbeads (MCMB), and graphite fibers, as well as any amorphous carbon material. In some embodiments, the anode electrode and the cathode electrode are separated from each other by a porous separator.

[0048] In some embodiments, the anode is a composite anode that includes an active material such as silicon and silicon alloys and a conductive polymer coating around the active material. The active material can be in the form of silicon particles having a particle size between about 1 nm and about 100 pm. Other suitable active materials include, but are not limited to, hard carbon, graphite, tin, and germanium particles. The polymer coating material can be cyclized using heat treatment at temperatures from 200 °C to 400 °C, thereby converting the polymer into a ladder compound by cross-linking the polymer chains. Specific polymers that can be used include, but are not limited to, polyacrylonitrile (PAN), where cyclization converts the nitrile bond (CºN) into a double bond (C=N). The polymer material forms a resilient yet strong film to allow for controlled fracturing / crushing of the silicon particles within the polymer matrix. In addition, the PAN matrix also provides a pathway for lithium ion migration, thereby improving the conductivity of the composite anode. The resulting anode material can overcome the swelling and conductivity challenges of silicon-based anodes, such as by providing a binder that can prevent the silicon particles from swelling and a conductive additive for providing a pathway for lithium ion migration. In some embodiments, the polymer is about 10 wt% to 40 wt% of the anode composite material. Additional descriptions of these Si-PAN composite anodes are provided in U.S. Patent Nos. 10,573,884 and 10,707,481, the entire contents of which are incorporated herein by reference.

[0049] Separators for lithium batteries are typically microporous polymer films. Examples of polymers used to form the films include polypropylene, polyethylene, nylon, cellulose, nitrocellulose, polysulfone, polyacrylonitrile, polyvinylidene fluoride, polybutylene, or a copolymer or blend of any two or more such polymers. In some cases, the separator is a microporous polyolefin separator that is electron beam treated. The electron treatment can increase the deformation temperature of the separator, which can increase the thermal stability of the separator at high temperatures. Additionally or alternatively, the separator can be a shut-down separator. A shut-down separator can have a trigger temperature above about 130 °C to allow the electrochemical cell to operate at temperatures up to about 130 °C.

[0050] The present disclosure will be further illustrated with reference to the following specific examples. It is to be understood that these examples are given by way of illustration and are not intended to limit the present disclosure or the subsequent claims.

[0051] Example A - Synthesis of Triethylene Glycol-Thiacyclopentane

[0052]

[0053] 1. Triethylene glycol and dichloromethane (DCM) (20 mL) were added to a 100 mL three-necked flask equipped with a magnetic stir bar, water-cooled condenser, N2inlet, and thermocouple. Triethylamine was added by pipette, observing an exotherm to 24 °C. The mixture was cooled to 0 °C in an ice bath.

[0054] 2. While stirring at 0 °C, thionyl chloride was added slowly dropwise by syringe. A maximum exotherm to 15 °C was observed, and a white solid ppt (triethylamine-HCl) formed rapidly. When the addition was complete, the ice bath was removed. The colorless mixture was allowed to come to room temperature slowly and stirred for 1 h.

[0055] 3. Deionized water (2 x 20 mL) was added, and the mixture was poured into a separatory funnel. The organic phase was extracted into DCM, separated, dried over MgSO4, filtered, and the solvent stripped by rotary evaporation to give an oil. The oil was pumped down under high vacuum. The oil was filtered through a 0.45 mm GMF filter and dried through a vacuum oven (5 mbar, 60 °C). Yield: dense colorless oil, 2.5 g (99%).

[0056] FTIR: 2870, 1198, 873, 698 cm -1

[0057] Example B - Synthesis of triethylene glycol phenyl phosphate

[0058]

[0059] 1. Triethylene glycol and DCM (10 mL) were added to a 40 mL vial equipped with a magnetic stir bar and thermocouple. Triethylamine was added by pipette, observing no exotherm.

[0060] 2. While stirring at room temperature, phenyl phosphorodichloridate was added slowly dropwise by syringe. An exotherm to 42 °C was observed, and a white solid ppt (triethylamine-HCl) formed rapidly. The pale yellow mixture was allowed to come to room temperature slowly and stirred for 1 h.

[0061] 3. Deionized water (2 x 10 mL) was added, and the mixture was poured into a separatory funnel. The organic phase was extracted into DCM, separated, washed with 5% HC1 (5 mL), separated, dried over MgSO4, and the solvent stripped by rotary evaporation to give an oil. Crude yield: dense yellow oil, 1.6 g (>99%).

[0062] FTIR: 3459, 2970, 1735, 1364, 1219, 931, 525 cm -1 .

[0063] Example C - Electrolyte for NMC622 / Gr battery

[0064] Electrolyte formulations were prepared in a dry, argon-filled glove box by combining all electrolyte components in glass vials and stirring for 24 hours to ensure complete salt dissolution. Functionalized crown ethers were added to the base electrolyte formulation, which consisted of a 3:7 weight mixture of ethylene carbonate (“EC”) and ethyl methyl carbonate (“EMC”) and 1M lithium hexafluorophosphate (“LiPF6”) dissolved therein as Li… + Ionically conductive salts. Conventional additives, such as vinylene carbonate (“VC”) and fluoroethylene carbonate (“FEC”). Comparative Example 1 (CE1) as shown in Table A. Example 1 (EE1) uses representative example molecules according to this disclosure. The electrolyte components and additives used are summarized in Table A.

[0065] Table A - Electrolyte Formulations for NMC 622 / Gr Batteries

[0066]

[0067] Example D-NMC 622 / Gr battery electrochemical data

[0068] The prepared electrolyte formulation was used as the electrolyte in a 200mAh lithium-ion pouch cell containing a lithium nickel manganese cobalt oxide (NMC622) cathode active material and graphite as the anode active material. 0.9 mL of the electrolyte formulation was added to each cell and allowed to soak for 1 hour. The cells were vacuum-sealed and initially charged at 25°C for 10 hours, followed by soaking. The cells were then charged to 3.8V at a C / 25 rate, degassed, and then vacuum-sealed. After degassed, the cells were charged and discharged twice at a C / 10 rate between 4.45 and 3.0V. The results are summarized in Table B. The dQ / dV curves are shown in... Figure 1 As shown, this indicates that the addition of the functionalized crown ether leads to a reduction peak at 2.4V during the initial charging of the battery. This additional reduction peak indicates a change in the resulting SEI. AC-IR is the internal resistance measured at 1 kHz, and the reported discharge capacity is the capacity after the last discharge at a C / 10 rate. Compared to CE1, the battery with EE1 electrolyte has a lower AC-IR value, which is a result of the additives in the electrolyte.

[0069] Table B - Initial Battery Data for NMC 622 / Gr Batteries

[0070] Electrolyte First coulombic efficiency (%) Formation discharge capacity (mAh) AC-IR (mΩ) CE1 87.4 203.5 97.5 EE1 86.9 200.4 92.4

[0071] Then, the battery was subjected to two hundred charge-discharge cycles at 25°C and a rate of 0.5C between 4.45 and 3.0V. Figure 2As can be seen, the discharge capacity retention of the battery with EE1 electrolyte is comparable to that of the battery with CE1, indicating that the functionalized crown ether additive can perform similar functions as a blend of conventional commercial additives. The capacity retention values are summarized in Table C.

[0072] Table C - Capacity retention data for NMC 622 / Gr batteries

[0073] Electrolyte Capacity retention after 50 cycles (%) Capacity retention after 100 cycles (%) CE1 90.6 74.3 EE1 93.7 79.0

[0074] Example E - Electrolytes for NMC 811 / SiO + Gr batteries

[0075] In a dry argon-filled glovebox, the formulations were prepared by combining all electrolyte components in a glass vial and stirring for 24 hours to ensure a completely homogeneous mixture. The individual components of the electrolyte formulations were EC, EMC, FEC, 1,3-propane sultone (PaS), ethylene sulfate (ESA), LiPF6, lithium difluorophosphate (LFO), lithium bis(oxalato)borate (LiBOB), and 1,3,6,9-tetraoxa-2-thia cycloundecane-2,2-dioxide (EFCE). The base formulation for all test formulations was 1M LiPF6in an EC / EMC 30 / 70 weight based solvent, with 1.0 wt% LFO, 1 wt% LiBOB, 5 wt% FEC, 0.5 wt% PaS, 0.5 wt% ESA. The examples used a representative example molecule according to the present disclosure, EFCE, at a concentration of 1.0 wt%, and was readily miscible in solution. The electrolyte components and additives used are summarized in Table D.

[0076] Table D - Electrolyte formulations for NMC 811 / SiO + Gr batteries

[0077]

[0078] Example F - NMC 811 / SiO + Gr battery electrochemical data

[0079] The prepared electrolyte formulation was used as the electrolyte in 900 mAh lithium ion pouch cells containing lithium nickel manganese cobalt oxide (NMC 811) cathode active material and graphite as anode active material combined with silicon oxide (silicon oxide) in a 9 to 1 ratio. In each cell, 2.5 mL of the electrolyte formulation was added and allowed to soak in the cell for 1 hour. The cells were vacuum sealed and primed at 25 °C for 24 hours, then soaked. The cells were then charged to 4.2 V at C / 10 rate, discharged to 2.7 V at C / 10 rate, then degassed, after which they were vacuum sealed. After degassing, the cells were cycled between 4.2 to 2.7 V at C / 10 rate twice, the results of which are summarized in Table E. The dQ / dV curves are shown in Figure 3

[0080] Table E - Initial cell data for NMC 811 / SiO+Gr cells

[0081] Electrolyte Initial discharge capacity (mAh) DCIR (mΩ) AC-IR (mΩ) CE2 956.0 92.9 26.6 EE2 956.8 80.3 22.5

[0082] The cells were then cycled between 4.2 to 2.7 V at 1.0 C rate two hundred times at 25 °C. As can be seen in Figure 4

[0083] Table F - Capacity retention data for NMC 811 / SiO+Gr cells

[0084] Electrolyte Capacity retention after 50 cycles (%) Capacity retention after 200 cycles (%) CE2 90.0 80.0 EE2 90.4 81.1

[0085] While various embodiments have been particularly described in the detailed description, those skilled in the relevant arts will appreciate that various modifications, additions, substitutions, and the like, can be made without departing from the spirit of the disclosure and these modifications, additions, substitutions, etc. are considered to be within the scope of the disclosure as defined in the following claims.​​

Claims

1. An electrochemical energy storage device electrolyte comprising: a non-protic organic solvent; a metal salt; and at least one compound according to Formula I, II, or III (I) (II) (III) wherein: n is an integer in the range of 2 to 8; X is independently oxygen or sulfur; and R is independently halogen, further bonded to a C1-C 12 substituted or unsubstituted alkyl group or C6-C 14 substituted or unsubstituted alkyl group or C6-C 12 substituted or unsubstituted alkyl group or C6-C 14 substituted or unsubstituted alkyl group or C6-C wherein any hydrogen atom can be replaced by an epoxide, halogen, alkyl, alkoxy, perfluoroalkyl, silyl, siloxy, silane, sulfoxide, amide, azo, ether, and thioether group or combinations thereof, or a carbon atom can be unsubstituted or can be substituted by an epoxide, halogen, alkyl, alkoxy, perfluoroalkyl, silyl, siloxy, silane, sulfoxide, amide, azo, ether, and thioether group or combinations thereof.

2. The electrolyte of claim 1, wherein the at least one compound according to Formula I, II, or III is one of the following structures:

3. The electrolyte of claim 1, wherein the at least one compound according to Formula I, II, or III is present at a concentration of 0.01 wt% to 10 wt% of the electrolyte.

4. The electrolyte of claim 1, wherein the non-protic organic solvent comprises a linear or cyclic carbonate, a carboxylate, a nitrite, an ether, a sulfone, a ketone, a lactone, a dioxolane, a glymes, a crown ether, a siloxane, a phosphate, a phosphite, a monophosphacene, or a polyphosphacene, or a mixture thereof.

5. The electrolyte of claim 1, wherein the non-protic organic solvent is present at a concentration of 50 wt% to 90 wt% of the electrolyte.

6. The electrolyte of claim 1, wherein the cation of the metal salt is an alkali metal.

7. The electrolyte of claim 6, wherein the alkali metal is lithium or sodium.

8. The electrolyte of claim 1, wherein the metal salt is present in the electrolyte at a concentration of 10 wt% to 30 wt%.

9. The electrolyte of claim 1, further comprising at least one additive.

10. The electrolyte of claim 9, wherein the at least one additive comprises a sulfur- containing compound, a phosphorus-containing compound, a boron-containing compound, a silicon-containing compound, a fluorine-containing compound, a nitrogen-containing compound, a compound containing at least one unsaturated carbon-carbon bond, a carboxylic anhydride, an epoxide, or a mixture thereof.

11. The electrolyte of claim 10, wherein the at least one additive is present in the electrolyte at a concentration of 0.01 wt% to 10 wt%.

12. An electrochemical energy storage device comprising: a cathode; an anode; the electrolyte of claim 1; and a separator.

13. The device of claim 12, wherein the cathode comprises lithium metal oxide, spinel, olivine, carbon-coated olivine, vanadium oxide, lithium peroxide, sulfur, lithium polysulfide, lithium monofluorophosphate, or a mixture thereof.

16. The device of claim 15, wherein the anode is a composite anode comprising an active material silicon or silicon alloy and a conductive polymer coating around the active material.

14. The device of claim 13, wherein the lithium metal oxide is LiCoO2, LiNiO2, LiNi x Co y Met z O2, LiMn 0.5 Ni 0.5 O2, LiMn 0.1 Co 0.1 Ni 0.8 O2, LiMn 0.2 Co 0.2 Ni 0.6 O2, LiMn 0.3 Co 0.2 Ni 0.5 O2, LiMn 0.33 Co 0.33 Ni 0.33 O2, LiMn2O4, Li 1+x 'Ni α Mn β Co γ Met' δ O 2-z 'F z ' or A n 'B2(XO4)3, wherein Met is Al, Mg, Ti, B, Ga, Si, Mn, or Co; Met' is Mg, Zn, Al, Ga, B, Zr, or Ti; A is Li, Ag, Cu, Na, Mn, Fe, Co, Ni, Cu, or Zn; B is Ti, V, Cr, Fe, or Zr; X is P, S, Si, W, or Mo; and wherein 0 < x < 0.3, 0 < y < 0.5, 0 < z < 0.5, 0 < x' < 0.4, 0 < a < 1, 0 < β < 1, 0 < γ < 1, 0 < δ < 0.4, 0 < z' < 0.4, and 0 < h' < 3.

15. The device of claim 12, wherein the anode comprises lithium metal, a graphite material, amorphous carbon, Li4Ti5O 12 , a tin alloy, silicon, a silicon alloy, an intermetallic compound, or a mixture thereof.

17. The device of claim 16, wherein the conductive polymer is polyacrylonitrile (PAN). ​ 18. The device of claim 12, wherein the separator comprises a porous separator separating the anode and the cathode from one another.

19. The device of claim 18, wherein the porous separator comprises an electron beam treated microporous polyolefin separator or a microporous polymer film comprising nylon, cellulose, nitrocellulose, polysulfone, polyacrylonitrile, polyvinylidene fluoride, polypropylene, polyethylene, polybutylene, or a copolymer or blend of any two or more such polymers.

20. The device of claim 12, wherein the aprotic organic solvent comprises an open chain or cyclic carbonate, carboxylate, nitrite, ether, sulfone, ketone, lactone, dioxolane, glymes, crown ether, siloxane, phosphate ester, phosphite ester, monophosphacalane, or polyphosphacalane, or a mixture thereof.

21. The device of claim 12, wherein the aprotic organic solvent is present in the electrolyte at a concentration of 50 to 90 weight percent.

22. The device of claim 12, wherein the cation of the metal salt is an alkali metal.

23. The device of claim 22, wherein the alkali metal is lithium or sodium.

24. The device of claim 12, wherein the metal salt is present in the electrolyte at a concentration of 10 to 30 weight percent.

25. The device of claim 12, wherein the electrolyte further comprises at least one additive.

26. The device of claim 25, wherein the at least one additive comprises a sulfur- containing compound, a phosphorus-containing compound, a boron-containing compound, a silicon-containing compound, a fluorine-containing compound, a nitrogen-containing compound, a compound containing at least one unsaturated carbon-carbon bond, a carboxylic anhydride, an epoxide, or a mixture thereof.

27. The device of claim 25, wherein the at least one additive is present in the electrolyte at a concentration of 0.01 to 10 weight percent.

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