Lithium batteries comprising in SITU ring-opening polymerization polymer electrolyte

Abstract

Disclosed herein is a semi-solid polymer electrolyte comprising an electrolyte salt, a solvent and a polymer obtained via an in situ ring-opening polymerization of a monomer without any catalyst other than the electrolyte salt. An electrochemical device comprising the electrolyte exhibits an improved cycling performance and fast charging performance.

Description

Atty Docket #: F125PCT SEMI-SOLID POLYMER ELECTROLYTE COMPRISING POLYMER VIA IN SITURING-OPENING POLYMERIZATION AND LITHIUM METAL BATTERIES COMPRISING SAME CROSS-REFERENCE|0001| The present application claims priority of US Serial No. 63 / 690,955, filed September 5, 2024, the entire content of which is incorporated herein by reference into this application.TECHNICAL FIELD

[0002] The present disclosure relates to a semi-solid electrolyte comprising a solvent, an electrolyte salt, and a polymer obtained by an in situ ring-opening polymerization of a monomer.BACKGROUND

[0003] Lithium metal batteries are widely investigated for the relatively higher energy density due to use of lithium metal as anode. Because of the high reactivity of lithium metal, electrolyte becomes a critical aspect for developing lithium metal battery with a desirable stability and cycle life. All solid- state polymer electrolyte is substantially free of solvent and exhibits a low ionic conductivity at ambient or low temperature and poor processability. In comparison to all solid-state polymer electrolyte, semi-solid polymer electrolytes comprise a solvent and exhibit a relatively high ionic conductivity and great processability. On one hand, conventional solvents such as ester and carbonate solvents are subject to deterioration in the presence of lithium metal. On the other hand, conventional radical initiators such as 2,2'-azobis(2-methylpropionitrile) (AIBN) and benzoyl peroxide (BPO) are usually used for in situ polymerization. The presence of initiator and its residue, however, may lead to formation of bubbles and other impurities that deteriorate the performance of an electrochemical device such as lithium metal batteries. Thus, there remains a need for new electrolytes.SUMMARY

[0004] Disclosed herein is a semi-solid polymer electrolyte (alternatively gel polymer electrolyte or quasi-solid polymer electrolyte) comprising a solvent, an electrolyte salt and a polymer obtained via an in situ ring-opening polymerization. In some embodiments, the polymer is obtained by an in situ ring-opening polymerization of a monomer without any catalyst other than the electrolyte salt. In some embodiments, the electrolyte salt can cause or catalyze a ring-opening polymerization.

[0005] In some embodiments, the monomer for the ring-opening polymerization is a cyclic ether. In some embodiments, the cyclic ether is represented by Formula (I-a) or (I-b)wherein Rla, R2aand R3aare each independently selected from the group consisting of -H, -F, Cl, -Br, -I, and Ci-io alkyl, and X is selected from the group consisting of CH2, N-C1-10 alkyl, O and S, and Rlb, R2band R3bare each independently selected from the group consisting of -H, -F, Cl, -Br, -I, and Ci-10 alkyl.

[0006] In some embodiments, the solvent comprises an ether with Formula (II)(ii), wherein R4is selected from the group consisting of C2-10 alkyl, C2-10 fluoroalkyl, -[(C1-4 alkylene)-0-]x-(C2-io alkyl), and -[(Ci-4 alkylene)-0-]x-(C2-io fluoroalkyl),R5, R6and R7are independently selected from the group consisting of H, F, C2-10 alkyl, C2-10 fluoroalkyl, -0-(C2-io alkyl), -0-(C2-io fluoroalkyl), -[(C1-4 alkylene)-0-]y-(C2-io alkyl), -[(C1-4 alkylene)-0-]y-(C2-io fluoroalkyl), -O-[(Ci-4 alkylene)-0-]y-(C2-io alkyl), and -O-[(Ci-4 alkylene)- 0-]y-(C2-io fluoroalkyl), x and y are independently an integer in a range from 1 to 10, and at least one of R3, R6and R7is not hydrogen (H).

[0007] In some embodiments, the ether has a boiling point of at least 100 °C at 1 atm. An electrochemical device comprising the semi-solid electrolyte such as lithium metal battery exhibits an improved cycling performance and fast charging performance.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Non-limiting embodiments of the present disclosure will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the disclosure shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure.[0009| Fig. 1 shows the specific capacities at various charge rates (up to 2.5C = 7.5 mA / cm2) of a coin cell comprising Li metal as anode, lithium nickel manganese cobalt oxide (LiNio.8Mno.1Coo.1O2, NMC811) composite electrode as cathode, microporous membrane as separator, and an electrolyte according to one embodiment of the present disclosure.[00101 Fig. 2 shows the Coulombic efficiency (CE) at various charge rates (up to 2.5C = 7.5 mA / cm2) of a coin cell comprising Li metal as anode, NMC811 composite electrode as cathode, microporous membrane as separator, and an electrolyte according to one embodiment of the present disclosure.

[0011] Fig. 3 shows the cycling performance of a pouch cell comprising example 2-1 as electrolyte in view of specific discharge capacity according to one embodiment of the present disclosure.

[0012] Fig. 4 shows the cycling performance of a pouch cell comprising example 2-1 as electrolyte in view of discharge capacity retention according to one embodiment of the present disclosure.(0013] Fig. 5 shows the cycling performance of a pouch cell comprising example 2-1 as electrolyte in view of coulombic efficiency (CE) according to one embodiment of the present disclosure.DETAILED DESCRIPTION

[0014] Disclosed herein is a semi-solid polymer electrolyte comprising a solvent, an electrolyte salt, and a polymer via an in situ ring-opening polymerization of a monomer. In some embodiments, the electrolyte salt causes the in situ ring-opening polymerization. In some embodiments, the in situ ringopening polymerization is conducted without additional initiator or catalyst other than the electrolyte salt. In some embodiments, the solvent does not comprise any ester based solvent, carbonate based solvent or nitrile based solvent. In some embodiments, the solvent does not comprise ionic liquid.(0015] In some embodiments, the monomer for the ring-opening polymerization is a cyclic ether. In some embodiments, the in situ ring-opening polymerization of cyclic ether is a cationic polymerization. In some embodiments, the in situ ring-opening polymerization is conducted in the absence of any radical initiator. In some embodiments, the in situ ring-opening polymerization is conducted in the absence of additional initiator or catalyst other than the electrolyte salt.

[0016] In some embodiments, the cyclic ether is represented by Formula (I-a) or (Lb)wherein Rla, R2aand R3aare each independently selected from the group consisting of -H, -F, Cl, -Br, -I, and Ci-10 alkyl, and X is one selected from the group consisting of CH2, N-C1-10 alkyl, O and S, and Rlb, R2band R3bare each independently selected from the group consisting of -H, -F, Cl, -Br, -I, and Ci-10 alkyl.

[0017] In some embodiments, the solvent comprises an ether represented by Formula (II):wherein R4is selected from the group consisting of Ci-io alkyl, Ci-io fluoroalkyl, -[(C1-4 alkylene)- 0-]x-(Ci-io alkyl), and — [(Ci-4 alkylene)-0-]x-(Ci-io fluoroalkyl),R5, R6and R7are independently selected from the group consisting of H, F, C1-10 alkyl, C1-10 fluoroalkyl, -0-(Ci-io alkyl), -0-(Ci-io fluoroalkyl), -[(Ci-4 alkylene)-0-]y-(Ci-io alkyl), -[(Ci-4 alkylene)-0-]y-(Ci-io fluoroalkyl), -O-[(Ci-4 alkylene)-0-]y-(Ci-io alkyl), and -O-[(Ci-4 alkylene)- O-]y-(C 1-10 fluoroalkyl), and x and y are independently an integer in a range from 1 to 10.

[0018] In some embodiments, the ether with Formula (II) comprises at least 2 oxygen (O). In some embodiments, the ether with Formula (II) comprises at least 3 oxygen (O).

[0019] In some embodiments, the ether comprises a fluorine-free ether represented by Formula (11-a).(II-a), wherein R4ais selected from the group consisting of C2-10 alkyl, and -[(Ci-4 alkylene)-0-]x-(C2-io alkyl).R5a, R6aand R7aare independently selected from the group consisting of H, C2-10 alkyl, -0-(C2-io alkyl),-[(Ci-4 alkylene)-0-]y-(C2-io alkyl), and -O-[(Ci-4 alkylene)-0-]y-(C2-io alkyl), x and y are independently an integer in a range from 1 to 10, and at least one of R5a, R6aand R7ais not hydrogen (H).

[0020] In some embodiments, the ether with Formula (II-a) comprises at least 2 oxygen (O). In some embodiments, the ether with Formula (II-a) comprises at least 3 oxygen (O).[00211 In some embodiments, the solvent is substantially free of fluorine-free ether that contains methyl as terminal group. In some embodiments, the solvent is substantially free of dimethoxy methane and dimethoxy ethane which may lead to gas formation and deteriorate stability and safety.

[0022] In some embodiments, the solvent comprises a fluorinated ether represented by Formula (II- b):wherein R4bis selected from the group consisting of Ci-io alkyl, Ci-io fluoroalkyl, -[(C1-4 alkylene)-0-]x-(Ci-io alkyl), and -[(Ci-4 alkylene)-0-]x-(Ci-io fluoroalkyl),R5b, R6band R7bare independently selected from the group consisting of H, F, C1-10 alkyl, C1-10 fluoroalkyl, -0-(Ci-io alkyl), -0-(Ci-io fluoroalkyl), -[(C1-4 alkylene)-0-]y-(Ci-io alkyl), -[(C1-4 alkylene)-0-]y-(Ci-io fluoroalkyl), -O-[(Ci-4 alkylene)-O-]y-(Ci -10 alkyl), and -O-[(Ci-4 alkylene)- 0-]y-(Ci-io fluoroalkyl), x and y are independently an integer in a range from 1 to 10, and at least one of R4b, R5b, R6band R7bcomprises one or more fluorine (F).

[0023] In some embodiments, the ether with Formula (Il-b) comprises at least 2 oxygen (O). In some embodiments, the ether with Formula (Il-b) comprises at least 3 oxygen (O).|0024| In some embodiments, the solvent comprises a fluorine-free ether, a fluorinated ether, or a mixture thereof.

[0025] In some embodiments, one of R5b, R6band R7bin Formula (Il-b) is H. In some embodiments, two of R5b, R6band R7bin Formula (Il-b) are H. In some embodiments, one of R5b, R6band R7bin Formula (Il-b) is F. In some embodiments, two of R5b, R6band R711in Formula (Il-b) are F.|0026| In some embodiments, at least one of R5b, R6band R71’ in Formula (Il-b) is C1-10 alkyl, C1-10 fluoroalkyl, -0-(Ci-io alkyl), -0-(Ci-io fluoroalkyl), -[(C1-4 alkylene)-0-]y-(Ci-io alkyl), -[(C1-4 alkylene)-0-]y-(Ci-io fluoroalkyl), -O-[(Ci-4 alkylene)-0-]y-(Ci-io alkyl), or -O-[(Ci-4 alkylene)-O-]y- (C1-10 fluoroalkyl).[0027 [ In some embodiments, R4bincludes at least one fluorine and at least one of R3b, R6band R7bincludes at least one fluorine.

[0028] In some embodiments, R4bis C1-10 alkyl, C1-10 fluoroalkyl, -[(C1-4 alkylene)-0-]x-(Ci io alkyl), or -[(C1-4 alkylene)-O-]x-(Ci -10 fluoroalkyl). In some embodiments, R5b, R6band R7bare independentlyselected from the group consisting of H, F, Ci-io alkyl, Ci-io fluoroalkyl, -0-(Ci-io alkyl), -0-(Ci-io fluoroalkyl), -O-[(Ci-4 alkylene)-0-]y-(Ci-io alkyl), and -O-[(Ci-4 alkylene)-0-]y-(Ci-io fluoroalkyl).

[0029] In some embodiments, at least two of R5b, R6band R713in Formula (Il-b) are -0-(Ci-io alkyl), -0-(Ci-io fluoroalkyl), -[(Ci-4 alkylene)-0-]y-(Ci-io alkyl), -[(Ci-4 alkylene)-0-]y-(Ci-io fluoroalkyl), -O-[(Ci-4 alkylene)-0-]y-(Ci-io alkyl), or -O-[(Ci-4 alkylene)-0-]y-(Ci-io fluoroalkyl).

[0030] In some embodiments, at least two of R5b, R6band R713are independently selected from the group consisting of -0-(Ci-io alkyl), -0-(Ci-io fluoroalkyl), -O-(Ci-4 alkylene)-0-(Ci-io alkyl), and - O-(Ci-4 alkylene)-0-(Ci io fluoroalkyl).[00311 In some embodiments, R713in Formula (Il-b) can be H, F, alkyl such as methyl (Me) and ethyl, fluoroalkyl such as -CFs, -CHF2, and -CH2F, alkoxy such as -OMe, or fluoroalkoxy such as -OCH2CF3 and -OCH2CHF2.

[0032] In some embodiments, the fluorinated ether is an asymmetric fluorinated ether (AFE). In some embodiments, an asymmetric fluorinated ether (AFE) contains one oxygen atom such as 1 -ethoxy - 1,1,2,2,2-pentafluoroethane (CF3CF2-O-C2H5). In some embodiments, an AFE contains two or more oxygen atoms such as l,l,l,2,2-pentafluoro-3-(2-ethoxyethoxy)propane (CF3CF2CH2-O-CH2CH2-O- CH2CH3) and (CF3CH2O)4-z-C-(OCH2CH3)z, wherein z is 0, 1, 2, 3 or 4. To avoid any ambiguity, (CF3CH2O)4-z-C-(OCH2CH3)z is an AFE when z is 1, 2 or 3 while is not AFE when z is 0 or 4.10033] “Alkyl” refers to a radical of a straight-chain or branched saturated hydrocarbon group having from 1 to 20 carbon atoms (“C1-20 alkyl”). In some embodiments, an alkyl group has 1 to 10 carbon atoms (“Ci-10 alkyl”). In some embodiments, an alkyl group has 1 carbon atom (“Ci alkyl”). Examples of C1-6 alkyl groups include methyl (Ci), ethyl (C2), n-propyl (C3), isopropyl (C3), n-butyl (C4), tertbutyl (C4), sec -butyl (C4), isobutyl (C4), n-pentyl (Cs), 3-pentanyl (Cs), amyl (Cs), neopentyl (Cs), 3- methyl-2-butanyl (Cs), tertiary amyl (Cs), and n-hexyl (Ce). Additional examples of alkyl groups include n-heptyl (C7), n-octyl (Cs) and the like. Unless otherwise specified, each instance of an alkyl group is independently optionally substituted, i.e., unsubstituted (an “unsubstituted alkyl”) or substituted (a “substituted alkyl”) with one or more substituents; e.g., for instance from 1 to 5 substituents, 1 to 3 substituents, or 1 substituent. In certain embodiments, the alkyl group is unsubstituted C 1-10 alkyl (e.g., -CH3). In certain embodiments, the alkyl group is substituted Ci-ioalkyl. Common alkyl abbreviations include Me (-CH3), Et (-CH2CH3), i-Pr (-CH(CH3)2), n-Pr (- CH2CH2CH3), n-Bu (-CH2CH2CH2CH3), or i-Bu (-CH2CH(CH3)2).

[0034] “Fluoroalkyl” refers to a radical of a straight-chain or branched saturated hydrocarbon group having from 1 to 20 carbon atoms and having at least one fluorine atom (“Ci-2ofluoroalkyl”). In someembodiments, a fluoroalkyl group has 1 to 10 carbon atoms (“Ci-io alkyl”). In some embodiments, a fluoroalkyl group has 1 carbon atom (“Ci fluoroalkyl”). In some embodiments, Ci fluoroalkyl includes -CH2F, -CHF2, and -CF3. In some embodiments, a fluoroalkyl group has 2 carbon atoms (“C2 fluoroalkyl”). In some embodiments, exemplary C2 fluoroalkyl includes without limitation - CH2CH2F, -CH2CHF2, -CH2CF3, -CHFCF3, -CF2CF3, -CF2CHF2, -CF2CH2F, and -CF2CH3. In some embodiments, a fluoroalkyl group has 3 carbon atoms (“C3 fluoroalkyl”). In some embodiments, C3 fluoroalkyl includes without limitation -CH2CH2CH2F, -CH2CH2CHF2, -CH2CH2CF3, -CH2CHFCF3, -CH2CF2CF3, -CHFCF2CF3, -CF2CF2CF3, -CH(CHF2)2, -CH(CH2F)2, -CH(CF3)2 and -CF(CF3)2.

[0035] “Alkylene” refers to an alkyl group wherein two hydrogens are removed to provide a divalent radical, and which may be substituted or unsubstituted. In some embodiments, an alkylene group has 1 to 4 carbon atoms (“Ci-4 alkylene”). Unsubstituted C1-4 alkylene groups include, but are not limited to, methylene (-CH2-), ethylene (-CH2CH2-), propylene (-CH2CH2CH2-), and butylene (- CH2CH2CH2CH2-). Exemplary substituted C1-C4 alkylene groups, e.g., substituted with one or more alkyl (methyl) groups, include but are not limited to, substituted methylene (-CH(CH3)-, -C(CH3)2-), substituted ethylene (-CH(CH3)CH2-,-CH2CH(CH3)-, -C(CH3)2CH2-,-CH2C(CH3)2-), substituted propylene (-CH(CH3)CH2CH2-, -CH2CH(CH3)CH2-, -CH2CH2CH(CH3)-), and the like.

[0036] In some embodiments, the solvent has a boiling point of at least 100 °C, at least 110 °C, or at least 120 °C at 1 atm.

[0037] In some embodiments, the solvent comprises at least one selected from the group consisting of 1,2-diethoxy ethane (DEE), 1,2-dipropoxy ethane (DPE), 1,2-dibutoxy ethane (DBE), dibutyl ether, di -tert-butyl ether, tert-butyl ethyl ether, tert-butyl methyl ether, 1,4-di oxane, and mixtures thereof.

[0038] In some embodiments, the solvent comprises at least one selected from the group consisting of bis(2,2,2-trifluoroethoxy)methane (BTFM), 1, 1,1, 3,3, 3-hexafluoro-2-(l, 1,1, 3,3,3- hexafluoropropan-2-yloxymethoxy)propane, bis(3,3,3-trifluoropropoxy)methane, 1,1,1 -trifluoro-3- [(2,2,2-trifluoroethoxy)methoxy]propane, bis(2,2,3,3,3-pentafluoropropoxy)methane, 1, 1,1, 2,2- pentafluoro-3-((2,2,2-trifluoroethoxy)methoxy)propane, 2,2,2-trifluoroethyl 1,1,2,2-tetrafluoroethyl ether, l,2-(l,l,2,2-tetrafluoroethoxy)ethane (TFEE), tris(2,2,2-trifluoroethyl)orthoformate (TFEO), tris(2,2-difluoroethyl)orthoformate, 2-[difluoro(2,2,2-trifluoroethoxy)methoxy]-l,l,l- trifluoroethane, 1,1, 1 ,2,2-pentafluoro-2- {fluoro[bis(pentafluoroethoxy )]methoxy } ethane, 1,1, 1 ,2- tetrafluoro-2,2-bi s(trifluoromethoxy)ethane, 2- [ 1 , 1 -bi s(2,2,2-trifluoroethoxy)ethoxy ] - 1,1,1- trifluoroethane, l,l,l-trifluoro-2,2,2-tris(2,2,2-trifluoroethoxy)ethane, l,l,l,3,3,3-hexafluoro-2,2- bi s(2,2,3 ,3 ,3 -pentafluoropropoxy )propane, 2-[ 1 , 1 -bis(2-fluoroethoxy)ethoxy]- 1,1,1 -trifluoroethane,,lH,lH,5H-octafluoropentyl-l,l,2,2-tetrafluoroethyl ether (OTE), l, l,2,2-tetrafluoroethyl-2,2,3,3- tetrafluoropropyl ether (TTE), bis(2,2,2-trifluoroethyl) ether, lH,lH,2’H-perfluorodipropyl ether and mixtures thereof.

[0039] In some embodiments, the solvent has a weight concentration in a range from 20 wt% to 80 wt%, from 20 wt% to 75 wt%, from 20 wt% to 70 wt%, from 20 wt% to 65 wt%, from 20 wt% to 60 wt%, from 20 wt% to 55 wt%, from 20 wt% to 50 wt%, from 20 wt% to 45 wt%, from 20 wt% to 40 wt%, from 20 wt% to 35 wt%, or from 20 wt% to 30 wt% in the semi-solid polymer electrolyte.

[0040] In some embodiments, the electrolyte salt has a weight concentration in a range from 10 wt% to 60 wt%, from 10 wt% to 55 wt%, from 10 wt% to 50 wt%, from 10 wt% to 45 wt%, from 10 wt% to 40 wt%, or from 10 wt% to 35 wt% in the semi-solid polymer electrolyte.

[0041] In some embodiments, the asymmetric fluorinated ether (AFE) comprises at least one selected from the group consisting of:• 1,1,1 ,2,2-pentafluoro-3 -(2-methoxyethoxy)propane,• l,l,l,2,2-pentafluoro-3-(2-ethoxyethoxy)propane (AFE1),• 1,1, 2, 2-tetrafluoro-3-(2-ethoxy ethoxy )propane (AFE2),• 1,1,1 ,2,2-pentafluoro-3 -[2-(2-methoxyethoxy)ethoxy]propane,• l,l,l,2,2,3,3-heptafluoro-4-(2-methoxyethoxy)butane,• l,l,l,2,2,3,3-heptafluoro-4-[2-(2-methoxyethoxy)ethoxy]butane,• l,l,l,2,2,3,3,4,4-nonafluoro-6-(2-methoxyethoxy)hexane,• l,l,l,2,2,3,3,4,4,5,5,6,6,7,7,8,8-heptadecafluoro-10-[2-[2- (methoxy ethoxy )ethoxy]ethoxy]decane,• 1,1,1 ,3 ,3 ,3 -hexafluoro-2,2-dipropoxypropane,• l-[l-ethoxy-l-(2-fluoroethoxy)ethoxy]-l,l,2,2-tetrafluoroethane, and mixtures thereof.

[0042] In some embodiments, the semi-solid polymer electrolyte has an ionic conductivity of at least 1.00 mS / cm, at least 1.10 mS / cm, at least 1.20 mS / cm, at least 1.30 mS / cm, at least 1.40 mS / cm, or at least 1.50 mS / cm measured at 25 °C.

[0043] In some embodiments, the semi-solid polymer electrolyte is electrochemically compatible with high voltage lithium metal oxide cathodes such as NMC811. In some embodiments, the electrolyte has an oxidation potential of at least 4.00 V, at least 4.10 V or at least 4.25 V over Li / Li+.

[0044] In some embodiments, the electrolyte salt is a lithium salt comprising at least one selected from the group consisting of lithium bis(fluorosulfonyl)imide (LiFSI), lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPFs), lithium borofluoride (LiBFf), lithium hexafluoroarsenide(LiAsFe), lithium trifluoromethanesulfonate (LiCFiSOt), lithium bis(trifluoromethanesulfonyl)imide (LiN(CFsSO2)2, LiTFSI), lithium bis(oxalato)borate (LiBOB), lithium nitrate (LiNCh), lithium fluoroalkylphosphates (Li[PFx(CyF2y+i-zHz)6-x]) (l<x<5, l<y<8, and 0<z<2y-l), lithium bis(perfluoroethanesulfonyl)imide (LiBETI), lithium difluoro(oxalato)borate (LiDFOB), lithium fluorophosphate (Li2PO3F), lithium difluoro(bisoxalato)phosphate (UC4PO8F2), lithium tetrafluoro oxalato phosphate (LiC2PO4F4), lithium difluorophosphate (LiDFP), LiC(CF3SCh)3, lithium acetate, lithium trifluoromethyl acetate and mixtures thereof.

[0045] In some embodiments, the solvent comprises a fluorine-free ether and a fluorinated ether. In some embodiments, a mixture of a fluorine-free ether and fluorinated ether may reduce resistance, increase ionic conductivity, improve stability, improve flame retardancy, and / or improve the high- rate performance. In some embodiments, the fluorine-free ether comprises a non-fluorine halogen substitute, which may enhance thermal stability and safety.|0046] In some embodiments, the fluorine-free ether is selected from the group consisting of 1,2- di ethoxy ethane, 1,1 -di ethoxy ethane, 1 , 1 -dipropoxy-ethane, 1,2-dipropoxy-ethane, di ethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, tri(ethylene glycol) dimethyl ether, tri(ethylene glycol) diethyl ether, tri(ethylene glycol) dibutyl ether, tetra(ethylene glycol) dimethyl ether, tetra(ethylene glycol) diethyl ether, tetra(ethylene glycol) dibutyl ether, and the like.

[0047] In some embodiments, the solvent is substantially free of dimethoxy methane and dimethoxy ethane which may lead to gas formation and deteriorate stability and safety profde.

[0048] In some embodiments, the semi-solid polymer electrolyte comprises a polymer with a weight percentage in a range from 1 wt% to 50 wt% in the semi-solid polymer electrolyte. In some embodiments, the semi-solid polymer electrolyte comprises a polymer with a weight percentage in a range from 5 wt% to 24 wt% in the semi-solid polymer electrolyte. In some embodiments, when the monomer for preparing the polymer via an in situ polymerization is present in an amount less than 5 wt% in a precursor solution, it cannot lead to a mechanically stable gel. When the monomer for preparing the polymer via in situ polymerization is present in an amount greater than 24 wt% in a precursor solution, it may lead to precipitation of monomer or electrolyte salt, deteriorating the stability and ionic conductivity.

[0049] In some embodiments, the in situ ring-opening polymerization is conducted after mixing a monomer with an electrolyte salt and a solvent.

[0050] In some embodiments, the monomer for ring-opening polymerization comprises at least one selected from the group consisting of 1,3, 5 -tri oxane, 2-methyl-l,3,5-trioxane, 2-ethyl-l,3,5-trioxane, 2-propyl-l,3,5-trioxane, 2,4-dimethyl-l,3,5-trioxane, 2,4-diethyl-l,3,5-trioxane, 2,4-diproyl-l,3,5- trioxane, 2-methyl-4-ethyl-l,3,5-trioxane, 2,4,6-trimethyl-l,3,5-trioxane, 1,3 -di oxolane, 1,3-dioxane, 2-methyl-l ,3-dioxolane, 2,2-dimethyl-l,3-dioxolane, 2,4-dimethyl-l,3-dioxolane, 1,3,5-dioxazinane, 5-methyl-l,3,5-dioxazinane, 2,4,6-trimethyl-l,3,5-dioxazinane, 1,3,5-dioxathiane, 2,4,6-trimethyl- 1,3,5-dioxathiane, and mixtures thereof.

[0051] In some embodiments, the present disclosure also provides an electrochemical device comprising the semi-solid polymer electrolytes as disclosed herein.

[0052] In some embodiments, the electrochemical device is a coin cell, a pouch cell, a prismatic cell, or combinations thereof.

[0053] In some embodiments, the precursor solution of the polymer electrolyte is added in the electrochemical device, and then polymerized within the electrochemical device to form the polymer electrolyte.

[0054] In some embodiments, the electrochemical device comprises a lithium metal oxide such as NMC81 1 as cathode. In some embodiments, the electrochemical device is not a lithium-sulfur battery, which involves chemistry and / or reactions significantly different from lithium metal oxide cathode.

[0055] In some embodiments, the electrochemical device exhibits a capacity of at least 0.5 Ah, at least 1.0 Ah, at least 1.5 Ah or at least 2.0 Ah.

[0056] In some embodiments, the electrochemical device exhibits an initial coulombic efficiency (CE) of at least 87.0%, at least 88.0%, at least 89.0%, at least 90.0%, at least 91.0%, at least 92.0%, at least 92.5%, at least 93.0%, at least 93.5%, or at least 94.0% at 0.33C at a temperature of 25 °C.

[0057] In some embodiments, the electrochemical device exhibits an average CE of at least 98.5%, 98.7%, 98.9%, 99.0%, 99.1%, 99.2%, 99.3% for 120 cycles at 0.33C at a temperature of 25 °C.

[0058] In some embodiments, the electrochemical device exhibits an initial specific capacity of at least 160 mAh / g, at least 170 mAh / g, at least 180 mAh / g or at least 190 mAh / g at 0.33C at a temperature of 25 °C.

[0059] In some embodiments, the electrochemical device exhibits a specific capacity of at least 150 mAh / g, at least 155 mAh / g, at least 160 mAh / g or at least 165mAh / g after 150 cycles, where each cycle is charged and discharged at a rate of 0.33C at a temperature of 25 °C.

[0060] In some embodiments, the electrochemical device exhibits a capacity retention of at least 85%, at least 87%, at least 90%, at least 91%, at least 92% or at least 93% after 150 cycles, where each cycle is charged and discharged at a rate of 0.33C at a temperature of 25 °C.

[0061] The disclosure will be better understood by reference to the Experimental Details which follow, but those skilled in the art will readily appreciate that the specific experiments detailed are only illustrative, and are not meant to limit the disclosure as described herein, as numerous variations and modifications of these exemplary embodiments are possible without undue experimentation.

[0062] All such variations and modifications are within the scope of the teachings of this disclosure. It will be appreciated that the foregoing description and following examples, no matter how detailed they may appear in text, the disclosure may be practiced in many ways, and the disclosure should be construed in accordance with the appended claims and equivalents thereof.EXAMPLE 1

[0063] Electrolytes with compositions in Table 1 were prepared by mixing LiFSI as an electrolyte salt, 1,2-di ethoxy ethane (DEE) as solvent, and 1,3,5-trioxane (TO) as monomer followed by in situ ring-opening polymerization at 65 °C for 5 hours.Table 1 Electrolyte compositions prior to in situ ring-opening polymerization0064| Li stripping / plating coulombic efficiency (CE) is a critical parameter for the evaluation of electrolyte stability on Li metal anode. The Li stripping / plating CE was obtained by stripping / plating cycles in Li / Cu cells comprising Li metal as anode, Cu foil as cathode, microporous membrane as a separator, and electrolytes as prepared. The ionic conductivity (IC) of the electrolyte was calculated based on the bulk resistance obtained by electrochemical impedance spectroscopy (EIS) measurements at room temperature.Table 2 Electrochemical performance of electrolytes and cells comprising the samea: Initial CE is initial Li stripping capacity divided by initial Li plating capacity.b: Average CE is total Li stripping cycle capacity divided by total Li plating cycle capacity using Aurbach CE protocol with a current density of 1.0 mA / cm2, a capacity of 3.0 mAh / cm2, and a total of 50 cycles. [Adv. Energy Mater. 2017, 1702097],

[0065] The cells comprising examples 1-1 and 1-2 as electrolytes exhibited an initial CE of 94.44% and 93.09%, respectively. The cells comprising examples 1-1 and 1-2 as electrolytes exhibited an average CE of 99.36% and 99.29%, respectively.EXAMPLE 2

[0066] Electrolytes with compositions in Table 3 were prepared by mixing LiFSI as an electrolyte salt, a solvent comprising a fluorine-free ether (DEE) and a fluorinated ether (bis(2,2,2- trifluoroethoxy)methane, BTFM), and 1,3,5-trioxane (TO) as monomer followed by in situ ring opening polymerization at 65 °C for 5 hours. Comparative example 1 was prepared by mixing 36.3 wt% LiFSI, 32.5 wt% DEE, 29.5 wt% BTFM, 1.5 wt% pentaerythritol tetraacrylate (PETA), and 0.2 wt% AIBN as radical initiator followed by in situ radical polymerization at 65 °C for 5 hours. Example 2-4 that comprises 24.0 wt% of TO failed to form a homogeneous solution due to limited miscibility of TO with high concentration electrolyte. Example 2-5 that comprises 5.0 wt% of TO failed to form a free-standing gel under standard polymerization condition (65 °C for 5 hours).

[0067] Coin cells were assembled by following the method in example 1 except that the electrolytes of 2-1, 2-2, 2-3, and comparative example 1 were used as electrolyte. The ionic conductivity, initial CE, and average CE were tested according to the method in example 1. A cell comprising the electrolyte of the examples 2-1, 2-2, and 2-3 exhibited a higher coulombic efficiency (CE) and ionic conductivity than the comparative example 1. Because the CE is already near 100%, a small increase of CE could lead to significant improvement in Li metal stability and cycle life.Table 3 Electrolyte compositions prior to in situ ring-opening polymerization[0(168] As shown in Table 4, the cells comprising examples 2-1, 2-2 and 2-3 as electrolytes exhibited an initial CE of 96.21%, 96.95%, and 96.28%, respectively, which is higher than the comparative example 1. The cells comprising examples 2-1, 2-2 and 2-3 as electrolytes exhibited an average CEof 99.37%, 99.26% and 99.23%, respectively, which is also higher than the comparative example 1. Example 2-1, 2-2, and 2-3 exhibited higher ionic conductivity than comparative example 1. Each example including comparative example exhibited an ionic conductivity (IC) of at least 1.00 mS / cm.

[0069] Fig. 1 shows the charge rate test of a Li / NMC coin cell comprising Li metal as anode, microporous membrane as separator, NMC811 as cathode, and comparative example 1 or example 2- 1 as electrolyte. The cell was cycled with a set of charge current densities sequentially increasing from 0.15 mA / cm2to 7.5 mA / cm2, equivalent to 0.05C to 2.5C, respectively. The cell with example 2-1 as electrolyte delivered a higher capacity than the cell with comparative example 1 as electrolyte. Fig. 2 shows the CE of the same cells. The cell with example 2-1 as electrolyte has more stable CE than the cell with comparative example 1 as electrolyte.Table 4 Electrochemical performance of electrolytes and cells

[0070] A multi-layer pouch cell comprising Li metal as anode, microporous membrane as separator, NMC81 1 as cathode, and electrolyte example 2-1 as electrolyte was cycled between 2.8V to 4.25 V at 25 °C using a charge current density of 1.0 mA / cm2and discharge current density of 1.0 mA / cm2under an external pressure in a range from 0.2 MPa to 5.0 MPa. The specific discharge capacity, discharge capacity retention, and CE are shown in Fig. 3, Fig. 4, and Fig. 5, respectively. The initial specific discharge capacity is 189 mAh / g. The cycle life is 198 cycles which is determined when the discharge capacity drops to 80% of the initial discharge capacity. The coulombic efficiency (CE) is high and consistently greater than 99.4%.ASPECTS

[0071] In a first aspect, the present disclosure provides a semi-solid polymer electrolyte comprising:• an electrolyte salt;• a solvent; and• a polymer obtained by in situ ring-opening polymerization of a monomer,wherein the solvent comprises a fluorine-free ether, a fluorinated ether, or a mixture thereof and the electrolyte salt can catalyze the in situ ring-opening polymerization without initiator other than the electrolyte salt.

[0072] In a second aspect according to the first aspect, wherein the monomer is a cyclic ether and is represented by Formula (I-a) or (I-b):wherein Rla, R2aand R3aare each independently selected from the group consisting of -H, -F, Cl, -Br, -I, and Ci-10 alkyl, and X is an element selected from the group consisting of CH2, N-C1-10 alkyl, O and S; and Rlb, R2band R3bare each independently selected from the group consisting of -H, -F, Cl, - Br, -I, and C1-10 alkyl.

[0073] In a third aspect according to the first or second aspect, wherein the fluorine-free ether is represented by Formula (Il-a):(Il-a), wherein R4ais selected from the group consisting of C2-10 alkyl, and -[(C1-4 alkylene)-0-]x-(C2-io alkyl), R5a, R6aand R7aare independently selected from the group consisting of H, C2-10 alkyl, -0-(C2-io alkyl), -[(Ci-4 alkylene)-O-]y-(C2 -10 alkyl), and -O-[(Ci-4 alkylene)-0-]y-(C2-io alkyl), x and y are independently an integer in a range from 1 to 10, and at least one of R5a, R6aand R7ais not hydrogen (H). In some embodiments, the fluorine-free ether comprises at least two (2) oxygen (O).

[0074] In a fourth aspect according to the first or second aspect, the fluorinated ether is represented by Formula (Il-b) :wherein R4bis selected from the group consisting of Ci-io alkyl, Ci-io fluoroalkyl, -[(C1-4 alkylene)- 0-]x-(Ci-io alkyl), and -[(Ci-4 alkylene)-0-]x-(Ci-io fluoroalkyl),R5b, R6band R7bare independently selected from the group consisting of H, F, C1-10 alkyl, C1-10 fluoroalkyl, -0-(Ci-io alkyl), -0-(Ci-io fluoroalkyl), -[(Ci-4 alkylene)-0-]y-(Ci-io alkyl), -[(Ci-4 alkylene)-0-]y-(Ci-io fluoroalkyl), -O-[(Ci-4 alkylene)-0-]y-(Ci-io alkyl), and -O-[(Ci-4 alkylene)- 0-]y-(Ci-io fluoroalkyl), x and y are independently an integer in a range from 1 to 10, and at least one of R4b, R3b, R6band R7bcomprises one or more fluorine (F).

[0075] In a fifth aspect according to the fourth aspect, the fluorinated ether comprises at least two (2) oxygen (O).

[0076] In a sixth aspect according to the first aspect, the polymer has a weight percentage in a range from 5 wt% to 24 wt% in the semi-solid polymer electrolyte.

[0077] In a seventh aspect according to the sixth aspect, the electrolyte salt has a weight concentration in a range from 25 wt% to 60 wt% in the semi-solid polymer electrolyte. In some embodiments, the semi-solid polymer electrolyte has an ionic conductivity of at least 1.00 mS / cm measured at 25 °C.

[0078] In an eighth aspect according to the first aspect, the solvent has a weight concentration in a range from 20 wt% to 70 wt% in the semi-solid polymer electrolyte.

[0079] In a nineth aspect according to the first aspect, the monomer for the ring-opening polymerization comprises at least one selected from the group consisting of 1,3,5-trioxane, 2-methyl- 1,3,5-trioxane, 2-ethyl-l,3,5-trioxane, 2-propyl-l,3,5-trioxane, 2,4-dimethyl-l,3,5-trioxane, 2,4- di ethyl- 1,3,5-trioxane, 2, 4-diproyl- 1,3,5-trioxane, 2 -methyl -4-ethyl- 1,3,5-trioxane, 2,4,6-trimethyl- 1,3,5-trioxane, 1,3 -di oxolane, 1,3-dioxane, 2-methyl- 1,3 -di oxolane, 2,2-dimethyl-l,3-dioxolane, 2,4- dimethyl- 1,3 -dioxolane, 1,3,5-dioxazinane, 5-methyl-l,3,5-dioxazinane, 2,4,6-trimethyl-l,3,5- dioxazinane, 1,3,5-dioxathiane, 2,4,6-trimethyl-l,3,5-dioxathiane, and mixtures thereof.

[0080] In some embodiments, the fluorine-free ether comprises at least one selected from the group consisting of 1,2-di ethoxy ethane, 1,1 -di ethoxy ethane, 1,1 -dipropoxy-ethane, 1,2-dipropoxy-ethane, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol diethyl ether, diethylene glycol dibutyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, and mixtures thereof. In some embodiments, the fluorine-free ether further comprises diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether or combinations thereof.

[0081] In a tenth aspect according to the first aspect, the fluorinated ether comprises at least one selected from the group consisting of:• bis(2,2,2-trifluoroethoxy)methane (BTFM),• l,l,l,3,3,3-hexafhioro-2-(l,l, l,3,3,3-hexafluoropropan-2-yloxymethoxy)propane,• bi s(3 ,3 ,3 -trifluoropropoxy)methane,• 1,1,1 -trifluoro-3 -[(2,2,2-trifluoroethoxy)methoxy]propane,• bi s(2,2,3 ,3 ,3 -pentafluoropropoxy)methane,• 1, 1, l,2,2-pentafluoro-3-((2,2,2-trifluoroethoxy)methoxy)propane,• 2,2,2-trifluoroethyl 1,1,2,2-tetrafluoroethyl ether,• l,2-(l,l,2,2-tetrafluoroethoxy)ethane (TFEE),• tris(2,2,2-trifluoroethyl)orthoformate (TFEO),• tris(2,2-difluoroethyl)orthoformate,• 2-[difluoro(2,2,2-trifluoroethoxy)methoxy]-l , 1 , 1 -trifluoroethane,• 1,1,1 ,2,2-pentafluoro-2- { fluorofbi s(pentafluoroethoxy)]methoxy } ethane,• 1,1,1 ,2-tetrafluoro-2,2-bis(trifluoromethoxy)ethane,• 2- [ 1 , 1 -bis(2,2,2-trifluoroethoxy)ethoxy ]- 1,1,1 -trifluoroethane,• l,l,l-trifluoro-2,2,2-tris(2,2,2-trifluoroethoxy)ethane,• 1,1,1 ,3 ,3 ,3 -hexafluoro-2,2-bi s(2,2,3 , 3 ,3 -pentafluoropropoxy )propane,• 2-[l,l-bis(2-fhioroethoxy)ethoxy]- 1,1,1 -trifluoroethane, and mixtures thereof.|0082] In some embodiments, the fluorinated ether comprises an asymmetric F-ether. In some embodiments, the asymmetric F-ether comprises at least one selected from the group consisting of 1 , 1 , 1 , 3 ,3 , 3 -hexafluoro-2,2-dipropoxypropane, 1 -[ 1 -ethoxy- 1 -(2-fluoroethoxy)ethoxy ]- 1 , 1 ,2,2- tetrafluoroethane, l,l,l,2,2-pentafluoro-3-(2-methoxyethoxy)propane, l,l,l,2,2-pentafluoro-3-(2- ethoxy ethoxy)propane, 1 , 1 ,2,2-tetrafluoro-3 -(2-ethoxy ethoxy )propane, 1,1, 1 ,2,2-pentafluoro-3 - [2- (2-methoxyethoxy)ethoxy]propane, 1,1, 1 ,2,2,3, 3-heptafluoro-4-(2 -methoxy ethoxy )butane, l,l,l,2,2,3,3-heptafluoro-4-[2-(2-methoxyethoxy)ethoxy]butane, l,l,l,2,2,3,3,4,4-nonafluoro-6-(2- methoxyethoxy)hexane, l,l, l,2,2,3,3,4,4,5,5,6,6,7,7,8,8-heptadecafluoro-10-[2-[2-(m ethoxy ethoxy)eth oxy] ethoxy] decane, and mixtures thereof.]0083] In an eleventh aspect according to the first aspect, the solvent has a boiling point of at least 100 °C at 1 atm.

[0084] In a twelfth aspect according to the first aspect, the solvent is substantially free of ester-based solvent, carbonate-based solvent and nitrile-based solvent. In some embodiments, the solvent issubstantially free of dimethoxy methane and dimethoxy ethane. In some embodiments, the solvent is substantially free of ionic liquid.

[0085] In a thirteenth aspect according to the first aspect, the electrolyte salt comprises at least one selected from the group consisting of lithium bis(fluorosulfonyl)imide (LiFSI), lithium perchlorate (LiCICh), lithium hexafluorophosphate (LiPFe), lithium borofluoride (IJBF4), lithium hexafluoroarsenide (LiAsFe), lithium trifluoromethanesulfonate (LiCFaSOa), lithium bis(trifluoromethanesulfonyl)imide (LiN(CF3SCh)2, LiTFSI), lithium bis(oxalato)borate (LiBOB), lithium nitrate (LiNCh), lithium fluoroalkylphosphates (Li[PFx(CyF2y+i-zHz)6-x]) (l<x<5, l<y<8, and 0<z<2y-l), lithium bis(perfluoroethanesulfonyl)imide (LiBETI), lithium difluoro(oxalato)borate (LiDFOB), lithium fluorophosphate (Li2PO3F), lithium difluoro(bisoxalato)phosphate (LiC4POsF2), lithium tetrafluoro oxalato phosphate (LiC2PO4F4), lithium difluorophosphate (LiDFP), LiC(CF3SC>2)3, lithium acetate, lithium trifluoromethyl acetate and mixtures thereof.

[0086] In a fourteenth aspect according to the first aspect, the semi-solid polymer electrolyte has an oxidation potential of at least 4.00 V over Li / Li+.

[0087] In a fifteenth aspect, the present disclosure provides an electrochemical device comprising the semi-solid polymer electrolyte according to any preceding aspect.

[0088] In some embodiments, the electrochemical device further comprises a cathode comprising a lithium metal oxide. In some embodiments, the lithium metal oxide comprises at least one selected from the group consisting of lithium cobalt oxide (LCO), lithium manganese oxide (LMO), and lithium nickel manganese cobalt oxide (NMC). In some embodiments, the electrochemical device exhibits a capacity of at least 0.5 Ah.

[0089] In some embodiments, the electrochemical device exhibits at least one characteristic selected from the group consisting of• an initial coulombic efficiency (CE) of at least 87.00% at 0.33 C at temperature of 25 °C,• an average CE of at least 98.5% for 150 cycles at 0.33 C at temperature of 25 °C,• an initial specific capacity of at least 160 mAh / g at 0.33 C at a temperature of 25 °C,• a specific capacity of at least 150mAh / g afterl50 cycles where each cycle is charged and discharged at a rate of 0.33C at a temperature of 25 °C, and• a capacity retention of at least 85% after 150 cycles where each cycle is charged and discharged at a rate of 0.33C at a temperature of 25 °C.

[0090] All transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., tomean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively.

[0091] Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[0092] Various embodiments of the features of this disclosure are described herein. However, it should be understood that such embodiments are provided merely by way of example, and numerous variations, changes, and substitutions can occur to those skilled in the art without departing from the scope of this disclosure. It should also be understood that various alternatives to the specific embodiments described herein are also within the scope of this disclosure.

Claims

We claim;1. A semi-solid polymer electrolyte comprising:• an electrolyte salt;• a solvent; and• a polymer obtained by an in situ ring-opening polymerization of a monomer, wherein the solvent comprises a fluorine-free ether, a fluorinated ether, or a mixture thereof, the electrolyte salt can catalyze the in situ ring-opening polymerization, and the in situ ringopening polymerization is performed without catalyst or initiator other than the electrolyte salt.

2. The semi-solid polymer electrolyte of claim 1, wherein the monomer is represented by Formula(I-a) or (I-b)wherein Rla, R2aand R3aare each independently selected from the group consisting of -H, -F, - Cl, -Br, -I, and Ci-io alkyl, and X is an element selected from the group consisting of CH2, N-Ci-10 alkyl, O and S; andRlb, R2band R3bare each independently selected from the group consisting of -H, -F, -Cl, -Br, -I, and Ci-10 alkyl.

3. The semi-solid polymer electrolyte of claim 1, wherein the fluorine-free ether is represented by Formula (Il-a):wherein R4ais selected from the group consisting of C2-10 alkyl, and -[(C1-4 alkylene)-O-]x-(C2- 10 alkyl), R5a, R6aand R7aare independently selected from the group consisting of H, C2-10 alkyl, -0-(C2-io alkyl), -[(Ci-4 alkylene)-0-]y-(C2-io alkyl), and -O-[(Ci-4 alkylene)-0-]y-(C2-io alkyl), x and y are independently an integer in a range from 1 to 10, and at least one of R5a, R6aand R7ais not hydrogen (H).

4. The semi-solid polymer electrolyte of claim 1, wherein the fluorinated ether is represented by Formula (Il-b):wherein R4bis selected from the group consisting of Ci-io alkyl, Ci-io fluoroalkyl, -[(Ci-4 alkylene)-0-]x-(Ci io alkyl), and -[(Ci-4 alkylene)-0-]x-(Ci io fluoroalkyl),R5b, R6band R7bare independently selected from the group consisting of H, F, Ci-io alkyl, Ci-io fluoroalkyl, -0-(Ci-io alkyl), -0-(Ci-io fluoroalkyl), -[(Ci-4 alkylene)-0-]y-(Ci-io alkyl), -[(Ci-4 alkylene)-0-]y-(Ci-io fluoroalkyl), -O-[(Ci-4 alkylene)-0-]y-(Ci-io alkyl), and -O-[(Ci-4 alkylene)-0-]y-(Ci-io fluoroalkyl), x and y are independently an integer in a range from 1 to 10, and at least one of R4b, R5b, R6band R7bcomprises one or more fluorine (F).

5. The semi-solid polymer electrolyte of claim 4, wherein the fluorinated ether comprises at least two (2) oxygen (O).

6. The semi-solid polymer electrolyte of claim 1, wherein the polymer has a weight percentage in a range from 5 wt% to 24 wt% in the semi-solid polymer electrolyte.

7. The semi-solid polymer electrolyte of claim 6, wherein the electrolyte salt has a weight concentration in a range from 25 wt% to 60 wt% in the semi-solid polymer electrolyte.

8. The semi-solid polymer electrolyte of claim 1 , wherein the solvent has a weight concentration in a range from 20 wt% to 70 wt% in the semi-solid polymer electrolyte.

9. The semi-solid polymer electrolyte of claim 1, wherein the monomer for the ring-opening polymerization comprises at least one selected from the group consisting of 1,3, 5 -tri oxane, 2- methyl-l,3,5-trioxane, 2-ethyl-l,3,5-trioxane, 2-propyl-l,3,5-trioxane, 2,4-dimethyl-l,3,5- trioxane, 2,4-diethyl-l,3,5-trioxane, 2,4-diproyl-l,3,5-trioxane, 2-methyl-4-ethyl-l,3,5- trioxane, 2,4,6-trimethyl-l,3,5-trioxane, 2-methyl-l,3-dioxolane, 2,2-dimethyl-l,3-dioxolane, 2, 4-dimethyl-l,3-di oxolane, 1,3,5-dioxazinane, 5-methyl-l,3,5-dioxazinane, 2,4,6-trimethyl- 1,3,5-dioxazinane, 1,3,5-dioxathiane, 2,4,6-trimethyl-l,3,5-dioxathiane, and mixtures thereof.

10. The semi-solid polymer electrolyte of claim 1, wherein the fluorinated ether comprises at least one selected from the group consisting of:• bis(2,2,2-trifluoroethoxy)methane (BTFM),• 1,1, 1,3, 3, 3 -hexafluoro-2-( 1 , 1 , 1 , 3 ,3 , 3 -hexafluoropropan-2-yloxy methoxy )propane,• bis(3,3,3-trifluoropropoxy)methane,• 1,1,1 -trifluoro-3 -[(2,2,2-trifluoroethoxy)methoxy]propane,• bis(2,2,3,3,3-pentafluoropropoxy)methane,• 1,1,1 ,2,2-pentafluoro-3 -((2,2,2-trifluoroethoxy)methoxy)propane,• 2,2,2-trifluoroethyl 1,1,2,2-tetrafluoroethyl ether,• l,2-(l,l,2,2-tetrafluoroethoxy)ethane (TFEE),• tris(2,2,2-trifluoroethyl)orthoformate (TFEO),• tris(2,2-difluoroethyl)orthoformate,• 2-[difluoro(2, 2, 2-trifluoroethoxy)m ethoxy]-!, 1, 1 -trifluoroethane,• l,l,l,2,2-pentafluoro-2-{fluoro[bis(pentafluoroethoxy)]methoxy]ethane,• 1,1,1 ,2-tetrafluoro-2,2-bis(trifluoromethoxy)ethane,• 2- [ 1 , 1 -bis(2,2,2-trifluoroethoxy)ethoxy]- 1,1,1 -trifluoroethane,• 1,1,1 -trifluoro-2,2,2-tris(2,2,2-trifluoroethoxy)ethane,• 1,1,1 ,3 ,3 ,3 -hexafluoro-2,2-bi s(2,2, 3 , 3 ,3 -pentafluoropropoxy)propane,• 2- [1,1 -bi s(2-fluoroethoxy)ethoxy]- 1,1,1 -trifluoroethane, and mixtures thereof.

11. The semi-solid polymer electrolyte of claim 1, wherein the solvent has a boiling point of at least 100 °C at 1 atm.

12. The semi-solid polymer electrolyte of claim 1, wherein the solvent is substantially free of ester-based solvent, carbonate-based solvent and nitrile-based solvent.

13. The semi-solid polymer electrolyte of claim 1, wherein the electrolyte salt comprises at least one selected from the group consisting of lithium bis(fluorosulfonyl) imide (LiFSI), lithium perchlorate (LiC104), lithium hexafluorophosphate (LiPFs), lithium borofluoride (LiBF4), lithium hexafluoroarsenide (LiAsFe), lithium trifluoromethanesulfonate (LiCFsSCh), lithium bis(trifluoromethanesulfonyl)imide (LiN(CF3SCh)2, LiTFSI), lithium bis(oxalato)borate (LiBOB), lithium nitrate (LiNCh), lithium fluoroalkylphosphates (Li[PFx(CyF2y+i-zHz)6-x]) (l<x<5, 1 <y<8, and 0<z<2y-l), lithium bis(perfluoroethanesulfonyl)imide (LiBETI), lithium difluoro(oxalato)borate (LiDFOB), lithium fluorophosphate (Li2POsF), lithium difluoro(bisoxalato)phosphate (LiC4POsF2), lithium tetrafluoro oxalato phosphate (LiC2PO4F4), lithium difluorophosphate (LiDFP), LiC(CF3SO2)3, lithium acetate, lithium trifluoromethyl acetate and mixtures thereof.

14. The semi-solid polymer electrolyte of claim 1, wherein the semi-solid polymer electrolyte has an oxidation potential of at least 4.00 V over Li / Li+.

15. An electrochemical device comprising the semi-solid polymer electrolyte of any of the preceding claims.

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