CN108281702A | 2018-07-13 | |||
US20170133716A1 | 2017-05-11 | |||
CN107170944A | 2017-09-15 | |||
US20170040649A1 | 2017-02-09 | |||
CN109980274A | 2019-07-05 |
Claims: 1. A rechargeable lithium battery comprising an anode, a cathode, and a quasi-solid or solid- state electrolyte in ionic communication with the anode and the cathode, wherein the electrolyte comprises a polyphosphazene polymer and a lithium salt dissolved or dispersed in the polymer, wherein the lithium salt occupies a weight fraction from 0.1% to 50% based on the total weight of the lithium salt and the polyphosphazene polymer combined; wherein the polyphosphazene polymer permeates into the anode and/or the cathode and in physical contact with and/or chemically bonded to an anode active material inside the anode and/or in physical contact with and/or chemically bonded to a cathode active material inside the cathode; and wherein the electrolyte further comprises from 0% to 50% by weight of a non-aqueous liquid solvent dispersed in the polymer, based on the total weight of the lithium salt, the polymer, and the non-aqueous liquid solvent combined. 2. The rechargeable lithium battery of claim 1, wherein the polyphosphazene polymer is selected from the groups consisting of (a) linear polymers having the formula (N=PR1R2)n, where R1 and R2 are organic; (b) cyclolinear and cyclomatrix polymers in which small phosphazene rings are connected together by organic chain units; (c) block copolymer, star, dendritic, or comb-type structures; and combinations thereof. 3. The rechargeable lithium battery of claim 1, wherein the polyphosphazene polymer is synthesized from a precursor monomer, oligomer, or reactive polymer selected from Chemical formula 1, Chemical formula 2, Chemical formula 3, Chemical formula 4, or a combination thereof: (Chemical formula 1) (Chemical formula 2) (Chemical formula 3) (Chemical formula 4). wherein R, R1 and R2 are independently selected from an organic group or an organometallic group. 4. The rechargeable lithium battery of claim 1, wherein the lithium salt is selected from lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium borofluoride (LiBF4), lithium hexafluoroarsenide (LiAsF6), lithium trifluoro-methanesulfonate (LiCF3SO3), bis- trifluoromethyl sulfonylimide lithium (LiN(CF3SO2)2), lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LiBF2C2O4), lithium nitrate (LiNO3), Li-fluoroalkyl-phosphates (LiPF3(CF2CF3)3), lithium bisperfluoro-ethysulfonylimide (LiBETI), lithium bis(trifluoromethanesulphonyl)imide, lithium bis(fluorosulphonyl)imide, lithium trifluoromethanesulfonimide (LiTFSI), an ionic liquid lithium salt, or a combination thereof. 5. The rechargeable lithium battery of claim 1, wherein the electrolyte further comprises from 0.1% to 50% by weight of a non-aqueous liquid solvent dispersed in the polymer, based on the total weight of the lithium salt, the polymer, and the non-aqueous liquid solvent combined. 6. The rechargeable lithium battery of claim 5, wherein the liquid solvent is selected from a fluorinated carbonate, hydrofluoroether, fluorinated vinyl carbonate, fluorinated ester, fluorinated vinyl ester, fluorinated vinyl ether, sulfone, sulfide, nitrile, phosphate, phosphite, phosphonate, sulfate, siloxane, silane, 1,3-dioxolane (DOL), 1,2-dimethoxyethane (DME), tetraethylene glycol dimethylether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), diethylene glycol dibutyl ether (DEGDBE), 2-ethoxyethyl ether (EEE), sulfone, sulfolane, ethylene carbonate (EC), dimethyl carbonate (DMC), methylethyl carbonate (MEC), diethyl carbonate (DEC), ethyl propionate, methyl propionate, propylene carbonate (PC), gamma-butyrolactone (γ-BL), acetonitrile (AN), ethyl acetate (EA), propyl formate (PF), methyl formate (MF), toluene, xylene, methyl acetate (MA), fluoroethylene carbonate (FEC), vinylene carbonate (VC), allyl ethyl carbonate (AEC), an ionic liquid solvent, or a combination thereof. 7. The rechargeable lithium battery of claim 6, wherein the sulfone or sulfide is selected from vinyl sulfone, allyl sulfone, alkyl vinyl sulfone, aryl vinyl sulfone, vinyl sulfide, a vinyl- containing variant of TrMS, MTrMS, TMS, EMS, MMES, EMES, EMEES, or a combination thereof: 8. The rechargeable lithium battery of claim 7, wherein the vinyl sulfone or sulfide is selected from ethyl vinyl sulfide, allyl methyl sulfide, phenyl vinyl sulfide, phenyl vinyl sulfoxide, allyl phenyl sulfone, allyl methyl sulfone, divinyl sulfone, or a combination thereof, wherein the vinyl sulfone does not include methyl ethylene sulfone and ethyl vinyl sulfone. 9. The rechargeable lithium battery of claim 6, wherein the nitrile comprises a dinitrile or is selected from AND, GLN, SEN, or a combination thereof: 10. The rechargeable lithium battery of claim 6, wherein the phosphate is selected from allyl- type, vinyl-type, styrenic-type and (meth)acrylic-type monomers bearing a phosphonate moiety. 11. The rechargeable lithium battery of claim 6, wherein the phosphate, phosphonate, phosphonic acid, phosphazene, or phosphite is selected from TMP, TEP, TFP, TDP, DPOF, DMMP, DMMEMP, tris(trimethylsilyl)phosphite (TTSPi), alkyl phosphate, triallyl phosphate (TAP), a combination thereof, wherein TMP, TEP, TFP, TDP, DPOF, DMMP, DMMEMP, and phosphazene have the following chemical formulae: wherein R = H, NH2, or C1 -C6 alkyl. 12. The rechargeable lithium battery of claim 6, wherein the siloxane or silane is selected from alkylsiloxane (Si-O), alkyylsilane (Si-C), liquid oligomeric silaxane (-Si-O-Si-), or a combination thereof. 13. The rechargeable lithium battery of claim 1, wherein the polyphosphazene forms a crosslinked network with an amide group selected from N,N-dimethylacetamide, N,N- diethylacetamide, N,N-dimethylformamide, N,N-diethylformamide, or a combination thereof. 14. The rechargeable lithium battery of claim 1, wherein the polyphosphazene is crosslinked by a crosslinking agent that comprises a compound having at least one reactive group selected from a hydroxyl group, an amino group, an imino group, an amide group, an acrylic amide group, an amine group, an acrylic group, an acrylic ester group, or a mercapto group in the molecule. 15. The rechargeable lithium battery of claim 1, wherein the polyphosphazene is crosslinked by a crosslinking agent selected from a phenylene group, poly(diethanol) diacrylate, poly(ethyleneglycol)dimethacrylate, poly(diethanol) dimethylacrylate, poly(ethylene glycol) diacrylate, or a combination thereof. 16. The rechargeable lithium battery of claim 1, wherein said electrolyte further comprises a flame-retardant additive selected from a halogenated flame retardant, phosphorus-based flame retardant, melamine flame retardant, metal hydroxide flame retardant, silicon-based flame retardant, phosphate flame retardant, biomolecular flame retardant, or a combination thereof. 17. The rechargeable lithium battery of claim 1, wherein said polyphosphazene polymer forms a mixture, copolymer, semi-interpenetrating network, or simultaneous interpenetrating network with a second polymer selected from poly(ethylene oxide), polypropylene oxide, poly(ethylene glycol), poly(acrylonitrile), poly(methyl methacrylate), poly(vinylidene fluoride), poly bis-methoxy ethoxyethoxide-phosphazene, polyvinyl chloride, polydimethylsiloxane, poly(vinylidene fluoride)-hexafluoropropylene, cyanoethyl poly(vinyl alcohol), a pentaerythritol tetraacrylate-based polymer, an aliphatic polycarbonate, a single Li-ion conducting solid polymer electrolyte with a carboxylate anion, a sulfonylimide anion, or sulfonate anion, a crosslinked electrolyte of poly(ethylene glycol) diacrylate, poly(ethylene glycol) methyl ether acrylate, a sulfonated derivative thereof, or a combination thereof. 18. The rechargeable lithium battery of claim 1, which is a lithium metal secondary cell, a lithium-ion cell, a lithium-sulfur cell, a lithium-ion sulfur cell, a lithium-selenium cell, or a lithium-air cell. 19. The rechargeable lithium battery of claim 1, wherein the cathode comprises a cathode active material selected from lithium nickel manganese oxide (LiNiaMn2-aO4, 0<a<2), lithium nickel manganese cobalt oxide (LiNinMnmCo1-n-mO2, 0<n<1, 0<m<1, n+m<1), lithium nickel cobalt aluminum oxide (LiNicCodAl1-c-dO2, 0<c<1, 0<d<1, c+d<1), lithium manganate (LiMn2O4), lithium iron phosphate (LiFePO4), lithium manganese oxide (LiMnO2), lithium cobalt oxide (LiCoO2), lithium nickel cobalt oxide (LiNipCo1-pO2, 0<p<1), or lithium nickel manganese oxide (LiNiqMn2-qO4, 0<q<2). 20. The rechargeable lithium battery of claim 1, which is a lithium-ion cell wherein the anode comprises an anode active material selected from the group consisting of: (a) silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), phosphorus (P), bismuth (Bi), zinc (Zn), aluminum (Al), titanium (Ti), nickel (Ni), cobalt (Co), and cadmium (Cd); (b) alloys or intermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Ni, Co, or Cd with other elements; (c) oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Fe, Ni, Co, V, or Cd, and their mixtures, composites, or lithium-containing composites; (d) salts and hydroxides of Sn; (e) lithium titanate, lithium manganate, lithium aluminate, lithium titanium niobate, lithium-containing titanium oxide, lithium transition metal oxide, ZnCo2O4; (f) carbon or graphite particles (g) prelithiated versions thereof; and (h) combinations thereof. 21. The rechargeable lithium battery of claim 1, further comprising a separator disposed between the anode and the cathode wherein the separator comprises the quasi-solid or solid-state electrolyte. 22. The rechargeable lithium battery of claim 1, wherein the electrolyte comprises a polyphosphazene polymer comprising a lithium salt dissolved or dispersed in the polyphosphazene polymer and wherein the separator further comprises polymeric fibers, ceramic fibers, glass fibers, or a combination thereof, which are dispersed in or bonded by the polyphosphazene polymer. 23. An electrolyte composition comprising a lithium salt and an initiator, a substituent, or a crosslinking agent dissolved or dispersed in a reactive liquid medium that comprises a reactive phosphazene compound, in a form of monomer, oligomer or reactive polymer. 24. The electrolyte composition of claim 23, wherein the electrolyte composition comprises: a. a first solution, comprising the reactive phosphazene compound which is in a liquid state or is dissolved in a first non-aqueous liquid solvent; and b. a second solution, comprising an initiator, a substituent, or a crosslinking agent, a lithium salt, and a second non-aqueous liquid solvent; wherein the first solution and the second solution are stored separately before the first solution and the second solution are mixed to form an electrolyte and wherein the first and the second non-aqueous liquid solvents are the same or different in composition. 25. The electrolyte composition of claim 23, wherein the reactive phosphazene compound comprises a precursor monomer, oligomer, or reactive polymer selected from Chemical formula 1, Chemical formula 2, Chemical formula 3, Chemical formula 4, or a combination thereof: wherein R, R1 and R2 are independently selected from an organic group or an organometallic group. 26. The electrolyte composition of claim 23, wherein the reactive phosphazene compound comprises a phosphazene derivative of the general formula: [-NP(A)a(B)b-]x, wherein the groups A and B are bonded to phosphorous atoms through --O--, --S--, --NH--, or --NR--, wherein R is a C1 - C6 alkyl group; A contains at least one of a vinyl ether group of the general formula Q--O--CR'=CHR" and a styrene ether group of the general formula: wherein at least one of R' and R" are hydrogen or a C1 - C10 alkyl group; B is a reactive or nonreactive hydrocarbon group; Q is one of an aliphatic, cycloaliphatic, aromatic, and heterocyclic hydrocarbon group optionally containing at least one of O, S, and N; a is a number greater than 0; b is 0 or a number greater than 0; a+b=2, x stands for a whole number that is at least 2; and z stands for 0 or 1. 27. The electrolyte composition of claim 23, wherein the reactive phosphazene compound comprises a phosphazene derivative of the general formula: [-NP(A)a(B)b-]x, wherein A and B are identical to or different from each other and independently represent a polymerization curable group containing an acryl group, a methacryl group, a vinyl group or an allyl group or a non-polymerization curable group, including a hydrogen atom, a halogen atom, a phenoxy group, a halogenated phenoxy group, an alkoxy group, a halogenated alkoxy group, an amino group, an alkylamino group, a halogenated alkylamino group or a mercapto group, wherein at least one of A and B is a polymerization curable group; a and b are independently each 0 or an integer larger than 0 and the sum of a and b is 2; and n is an integer of 3 or larger. 28. The electrolyte composition of claim 24, wherein the first non-aqueous liquid solvent or the second non-aqueous liquid solvent is selected from a fluorinated carbonate, hydrofluoroether, fluorinated vinyl carbonate, fluorinated ester, fluorinated vinyl ester, fluorinated vinyl ether, sulfone, sulfide, nitrile, phosphate, phosphite, phosphonate, phosphazene, sulfate, siloxane, silane, 1,3-dioxolane (DOL), 1,2-dimethoxyethane (DME), tetraethylene glycol dimethylether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), diethylene glycol dibutyl ether (DEGDBE), 2-ethoxyethyl ether (EEE), sulfone, sulfolane, ethylene carbonate (EC), dimethyl carbonate (DMC), methylethyl carbonate (MEC), diethyl carbonate (DEC), ethyl propionate, methyl propionate, propylene carbonate (PC), gamma.- butyrolactone (γ-BL), acetonitrile (AN), ethyl acetate (EA), propyl formate (PF), methyl formate (MF), toluene, xylene, methyl acetate (MA), fluoroethylene carbonate (FEC), vinylene carbonate (VC), allyl ethyl carbonate (AEC), an ionic liquid solvent, or a combination thereof. 29. The electrolyte composition of claim 23, wherein the lithium salt or initiator is selected from lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium borofluoride (LiBF4), lithium hexafluoroarsenide (LiAsF6), lithium trifluoro-methanesulfonate (LiCF3SO3), bis-trifluoromethyl sulfonylimide lithium (LiN(CF3SO2)2), lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LiBF2C2O4), lithium nitrate (LiNO3), Li-fluoroalkyl-phosphates (LiPF3(CF2CF3)3), lithium bisperfluoro- ethysulfonylimide (LiBETI), lithium bis(trifluoromethanesulphonyl)imide, lithium bis(fluorosulphonyl)imide, lithium trifluoromethanesulfonimide (LiTFSI), an ionic liquid lithium salt, or a combination thereof. 30. The electrolyte composition of claim 23, wherein the initiator is selected from PCl5, perfluoroalkyl iodide (C6F13I), an azo compound, azodiisobutyronitrile (AIBN), azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate, benzoyl peroxide tert-butyl peroxide, methyl ethyl ketone peroxide, benzoyl peroxide (BPO), bis(4-tert- butylcyclohexyl) peroxydicarbonate, t-amyl peroxypivalate, 2,2′-azobis-(2,4- dimethylvaleronitrile), 2,2′-azobis-(2-methylbutyronitrile), 1,1-azobis(cyclohexane-1- carbonitrile, benzoylperoxide (BPO), hydrogen peroxide, dodecamoyl peroxide, isobutyryl peroxide, cumene hydroperoxide, tert-butyl peroxypivalate, diisopropyl peroxydicarbonate, n‐C4H9Li, (C5H5)2Mg, (i‐C4H9)3Al, a carbenium salt, CF3SO3 CH3, CF3S03C2H5, (CF3SO2)O, Ph3C+AsF6-, 1-hydroxycyclohexylphenyl ketone, dibenzoyl, benzoyl methyl ether, benzoyl ethyl ether, p-chlorobenzophenone, p-methoxybenzophenone, di-tert.-butyl peroxide and camphaquinone, phosphite, a cationic initiator, an acid, a lithium salt, or a combination thereof. 31. The electrolyte composition of claim 23, further including a non-aqueous liquid solvent. 32. The electrolyte composition of claim 26, wherein B is a reactive or nonreactive hydrocarbon group containing at least one of O, S, and N, and containing at least one reactive group. 33. An electrolyte composition comprising a non-aqueous liquid solvent, a lithium salt, and a reactive phosphazene compound dissolved in the liquid solvent, wherein the non-aqueous liquid solvent is selected from a fluorinated carbonate, hydrofluoroether, fluorinated vinyl carbonate, fluorinated ester, fluorinated vinyl ester, fluorinated vinyl ether, sulfone, sulfide, nitrile, phosphate, phosphite, phosphonate, phosphazene, sulfate, siloxane, silane, 1,3- dioxolane (DOL), 1,2-dimethoxyethane (DME), tetraethylene glycol dimethylether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), diethylene glycol dibutyl ether (DEGDBE), 2-ethoxyethyl ether (EEE), sulfone, sulfolane, ethylene carbonate (EC), dimethyl carbonate (DMC), methylethyl carbonate (MEC), diethyl carbonate (DEC), ethyl propionate, methyl propionate, propylene carbonate (PC), gamma-butyrolactone (γ-BL), acetonitrile (AN), ethyl acetate (EA), propyl formate (PF), methyl formate (MF), toluene, xylene, methyl acetate (MA), fluoroethylene carbonate (FEC), vinylene carbonate (VC), allyl ethyl carbonate (AEC), an ionic liquid solvent, or a combination thereof. 34. The electrolyte composition of claim 33, wherein the lithium salt is selected from lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium borofluoride (LiBF4), lithium hexafluoroarsenide (LiAsF6), lithium trifluoro-methanesulfonate (LiCF3SO3), bis- trifluoromethyl sulfonylimide lithium (LiN(CF3SO2)2), lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LiBF2C2O4), lithium nitrate (LiNO3), Li-fluoroalkyl-phosphates (LiPF3(CF2CF3)3), lithium bisperfluoro-ethysulfonylimide (LiBETI), lithium bis(trifluoromethanesulphonyl)imide, lithium bis(fluorosulphonyl)imide, lithium trifluoromethanesulfonimide (LiTFSI), an ionic liquid lithium salt, or a combination thereof. 35. An anode comprising an anode active material that is mixed with the electrolyte composition of claim 23 and is in physical contact with or chemically bonded to the electrolyte composition upon curing. 36. A cathode comprising particles of a cathode active material that are mixed with the electrolyte composition of claim 23 and is in physical contact with or chemically bonded to the electrolyte composition upon curing. |
In certain embodiments, the sulfone as a liquid solvent is selected from TrMS, MTrMS, TMS, or vinyl or double bond-containing variants of TrMS, MTrMS, TMS, EMS, MMES, EMES, EMEES, or a combination thereof; their chemical formulae being given below: The nitrile as a liquid solvent or as an additive to a liquid solvent may be selected from a dinitrile, such as AND, GLN, SEN, or a combination thereof and their chemical formulae are given below: In some embodiments, the liquid solvent is selected from phosphate, alkyl phosphonate, phosphazene, phosphite, or sulfate; e.g., tris(trimethylsilyl) phosphite (TTSPi), alkyl phosphate, triallyl phosphate (TAP), ethylene sulfate (DTD), a combination thereof, or a combination with 1,3-propane sultone (PS) or propene sultone (PES). The phosphate, alkyl phosphonate, or phosphazene may be selected from the following:
wherein R = H, NH 2 , or C 1 -C 6 alkyl. The disclosed electrolyte may be initially in a reactive liquid electrolyte composition form, comprising a lithium salt and an initiator, a substituent, a co-monomer, or a crosslinking agent dissolved or dispersed in a reactive liquid medium comprising a reactive phosphazene compound (monomer, oligomer, or reactive polymer). In certain preferred embodiments, the electrolyte composition comprises: (a) a first solution, comprising the reactive phosphazene compound which is in a liquid state or is dissolved in a first non-aqueous liquid solvent; and (b) a second solution, comprising an initiator (including catalyst, accelerator, promoter, etc., where needed), substituent, or crosslinking agent, a lithium salt, and a second non-aqueous liquid solvent; wherein the first solution and the second solution are stored separately before the first solution and the second solution are mixed to form an electrolyte. The first non-aqueous liquid solvent may be the same as or different than the second non-aqueous liquid solvent. The reactive liquid electrolyte composition may further comprise a curing agent (a crosslinking agent or co-polymerization monomer) selected from an amide group, such as N,N- dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide, N,N-diethylformamide, or a combination thereof. In some embodiments, the crosslinking agent may comprise a compound having at least one reactive group selected from a hydroxyl group, an amino group, an imino group, an amide group, an acrylic amide group, an amine group, an acrylic group, an acrylic ester group, or a mercapto group in the molecule. In certain embodiments, the crosslinking agent is selected from a phenylene group, poly(diethanol) diacrylate, poly(ethyleneglycol) dimethacrylate, poly(diethanol) dimethylacrylate, or poly(ethylene glycol) diacrylate. The initiator or a co-initiator may be selected from an azo compound (e.g., azodiisobutyronitrile, AIBN), azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate, perfluoroalkyl iodide (C 6 F 13 I), benzoyl peroxide tert-butyl peroxide and methyl ethyl ketone peroxide, benzoyl peroxide (BPO), bis(4-tert-butylcyclohexyl) peroxydicarbonate, t-amyl peroxypivalate, 2,2′-azobis-(2,4-dimethylvaleronitrile), 2,2′-azobis-(2- methylbutyronitrile), 1,1-azobis(cyclohexane-1-carbonitrile, benzoylperoxide (BPO), hydrogen peroxide, dodecamoyl peroxide, isobutyryl peroxide, cumene hydroperoxide, tert-butyl peroxypivalate, diisopropyl peroxydicarbonate, or a combination thereof. The initiator may be selected from PCl 5 , n‐C 4 H 9 Li, (C 5 H 5 ) 2 Mg, (i‐C 4 H 9 ) 3 Al, a carbenium salt, CF 3 SO3CH 3 , CF 3 S03C 2 H 5 , (CF 3 SO 2 )O, Ph3C + AsF 6 -, a lithium salt, or a combination thereof. The initiator may comprise a lithium salt selected from lithium hexafluorophosphate (LiPF 6 ), lithium borofluoride (LiBF 4 ), lithium hexafluoroarsenide (LiAsF 6 ), lithium trifluoro- methanesulfonate (LiCF 3 SO 3 ), bis-trifluoromethyl sulfonylimide lithium (LiN(CF 3 SO 2 ) 2 ), lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LiBF 2 C 2 O 4 ), lithium oxalyldifluoroborate (LiBF 2 C 2 O 4 ), or a combination thereof. In other words, we have surprisingly observed that certain lithium salts actually participate in the polymerization reactions. The crosslinking agent preferably comprises a compound having at least one reactive group selected from a hydroxyl group, an amino group, an imino group, an amide group, an amine group, an acrylic group, or a mercapto group in the molecule. The amine group is preferably selected from the following structure: . The crosslinking agent may be selected from a phenylene group, N,N-methylene bisacrylamide, epichlorohydrin, 1,4-butanediol diglycidyl ether, tetrabutylammonium hydroxide, cinnamic acid, ferric chloride, aluminum sulfate octadecahydrate, diepoxy, dicarboxylic acid compound, poly(potassium 1-hydroxy acrylate) (PKHA), glycerol diglycidyl ether (GDE), ethylene glycol, polyethylene glycol, polyethylene glycol diglycidyl ether (PEGDE), citric acid (Formula 4 below), acrylic acid, methacrylic acid, a derivative compound of acrylic acid, a derivative compound of methacrylic acid (e.g. polyhydroxyethylmethacrylate), glycidyl functions, N,N'-Methylenebisacrylamide (MBAAm), Ethylene glycol dimethacrylate (EGDMAAm), isobomyl methacrylate, poly (acrylic acid) (PAA), methyl methacrylate, isobomyl acrylate, ethyl methacrylate, isobutyl methacrylate, n-Butyl methacrylate, ethyl acrylate, 2-Ethyl hexyl acrylate, n-Butyl acrylate, a diisocyanate (e.g. methylene diphenyl diisocyanate, MDI), an urethane chain, a chemical derivative thereof, or a combination thereof. The electrolyte may further comprise a flame-retardant additive, different in composition than the liquid solvent. Flame-retardant additives are intended to inhibit or stop polymer pyrolysis and electrolyte combustion processes by interfering with the various mechanisms involved—heating, ignition, and propagation of thermal degradation. The flame-retardant additive may be selected from a halogenated flame retardant, phosphorus-based flame retardant, melamine flame retardant, metal hydroxide flame retardant, silicon-based flame retardant, phosphate flame retardant, biomolecular flame retardant, or a combination thereof. There is no limitation on the type of flame retardant that can be physically or chemically incorporated into the elastic polymer. The main families of flame retardants are based on compounds containing: Halogens (Bromine and Chlorine), Phosphorus, Nitrogen, Intumescent Systems, Minerals (based on aluminum and magnesium), and others (e.g., Borax, Sb 2 O 3 , and nanocomposites). Antimony trioxide is a good choice, but other forms of antimony such as the pentoxide and sodium antimonate may also be used. One may use the reactive types (being chemically bonded to or becoming part of the polymer structure) and additive types (simply dispersed in the polymer matrix). For instance, reactive polysiloxane can chemically react with EPDM type elastic polymer and become part of the crosslinked network polymer. It may be noted that flame-retarding group modified polysiloxane itself is an elastic polymer composite containing a flame retardant according to an embodiment of instant disclosure. Both reactive and additive types of flame retardants can be further separated into several different classes: 1) Minerals: Examples include aluminum hydroxide (ATH), magnesium hydroxide (MDH), huntite and hydromagnesite, various hydrates, red phosphorus and boron compounds (e.g. borates). 2) Organo-halogen compounds: This class includes organochlorines such as chlorendic acid derivatives and chlorinated paraffins; organobromines such as decabromodiphenyl ether (decaBDE), decabromodiphenyl ethane (a replacement for decaBDE), polymeric brominated compounds such as brominated polystyrenes, brominated carbonate oligomers (BCOs), brominated epoxy oligomers (BEOs), tetrabromophthalic anyhydride, tetrabromobisphenol A (TBBPA), and hexabromocyclododecane (HBCD). 3) Organophosphorus compounds: This class includes organophosphates such as triphenyl phosphate (TPP), resorcinol bis(diphenylphosphate) (RDP), bisphenol A diphenyl phosphate (BADP), and tricresyl phosphate (TCP); phosphonates such as dimethyl methylphosphonate (DMMP); and phosphinates such as aluminum diethyl phosphinate. In one important class of flame retardants, compounds contain both phosphorus and a halogen. Such compounds include tris(2,3-dibromopropyl) phosphate (brominated tris) and chlorinated organophosphates such as tris(1,3-dichloro- 2-propyl)phosphate (chlorinated tris or TDCPP) and tetrakis(2-chlorethyl) dichloroisopentyldiphosphate (V6). 4) Organic compounds such as carboxylic acid and dicarboxylic acid The mineral flame retardants mainly act as additive flame retardants and do not become chemically attached to the surrounding system (the polymer). Most of the organohalogen and organophosphate compounds also do not react permanently to attach themselves into the polymer. Certain new non halogenated products, with reactive and non-emissive characteristics have been commercially available as well. In certain embodiments, the flame-retardant additive is in a form of encapsulated particles comprising the additive encapsulated by a shell of coating material that is breakable or meltable when exposed to a temperature higher than a threshold temperature (e.g., flame or fire temperature induced by internal shorting). The encapsulating material is a substantially lithium ion-impermeable and liquid electrolyte-impermeable coating material. The encapsulating or micro-droplet formation processes The flame-retardant additive-to-liquid solvent ratio in the mixture is from 1/95 to 99/1 by weight, preferably from 10/85 to 80/20 by weight, further preferably from 20/80 to 70/20 by weight, and most preferably from 35/65 to 65/35 by weight. In certain desirable embodiments, the electrolyte further comprises particles of an inorganic solid electrolyte material having a particle size from 2 nm to 30 µm, wherein the particles of inorganic solid electrolyte material are dispersed in the polymer or chemically bonded by the polymer. The particles of inorganic solid electrolyte material are preferably selected from an oxide type, sulfide type, hydride type, halide type, borate type, phosphate type, lithium phosphorus oxynitride (LiPON), garnet-type, lithium superionic conductor (LISICON) type, sodium superionic conductor (NASICON) type, or a combination thereof. The inorganic solid electrolytes that can be incorporated into an elastic polymer protective layer include, but are not limited to, perovskite-type, NASICON-type, garnet-type and sulfide-type materials. A representative and well-known perovskite solid electrolyte is Li 3x La 2/3 − x TiO 3 , which exhibits a lithium-ion conductivity exceeding 10 −3 S/cm at room temperature. This material has been deemed unsuitable in lithium batteries because of the reduction of Ti 4+ on contact with lithium metal. However, we have found that this material, when dispersed in an elastic polymer, does not suffer from this problem. The sodium superionic conductor (NASICON)-type compounds include a well-known Na 1 + x Zr 2 Si x P 3 − xO 12 . These materials generally have an AM 2 (PO 4 ) 3 formula with the A site occupied by Li, Na or K. The M site is usually occupied by Ge, Zr or Ti. In particular, the LiTi 2 (PO 4 ) 3 system has been widely studied as a solid state electrolyte for the lithium-ion battery. The ionic conductivity of LiZr 2 (PO 4 ) 3 is very low, but can be improved by the substitution of Hf or Sn. This can be further enhanced with substitution to form Li 1 + x M x Ti 2 − x (PO 4 ) 3 (M = Al, Cr, Ga, Fe, Sc, In, Lu, Y or La). Al substitution has been demonstrated to be the most effective solid state electrolyte. The Li 1 + x Al x Ge 2 − x(PO 4 ) 3 system is also an effective solid state due to its relatively wide electrochemical stability window. NASICON-type materials are considered as suitable solid electrolytes for high-voltage solid electrolyte batteries. Garnet-type materials have the general formula A3B2Si3O 12 , in which the A and B cations have eightfold and sixfold coordination, respectively. In addition to Li3M2Ln3O 12 (M = W or Te), a braod series of garnet-type materials may be used as an additive, including Li 5 La 3 M 2 O 12 (M = Nb or Ta), Li 6 ALa 2 M 2 O 12 (A = Ca, Sr or Ba; M = Nb or Ta), Li 5.5 La 3 M 1.75 B 0.25 O 12 (M = Nb or Ta; B = In or Zr) and the cubic systems Li7La3Zr 2 O 12 and Li 7.06 M 3 Y 0.06 Zr 1.94 O 12 (M = La, Nb or Ta). The Li 6.5 La 3 Zr 1.75 Te 0.25 O 12 compounds have a high ionic conductivity of 1.02 × 10 −3 S/cm at room temperature. The sulfide-type solid electrolytes include the Li 2 S–SiS2 system. The highest reported conductivity in this type of material is 6.9 × 10 −4 S/cm, which was achieved by doping the Li 2 S– SiS 2 system with Li 3 PO 4 . The sulfide type also includes a class of thio-LISICON ( lithium superionic conductor) crystalline material represented by the Li 2 S–P 2 S 5 system. The chemical stability of the Li 2 S–P 2 S 5 system is considered as poor, and the material is sensitive to moisture (generating gaseous H 2 S). The stability can be improved by the addition of metal oxides. The stability is also significantly improved if the Li 2 S–P 2 S 5 material is dispersed in an elastic polymer. These solid electrolyte particles dispersed in an electrolyte polymer can help enhance the lithium ion conductivity of certain polymers having an intrinsically low ion conductivity. Preferably and typically, the polymer has a lithium ion conductivity no less than 10 -5 S/cm, more preferably no less than 10 -4 S/cm, further preferably no less than 10 -3 S/cm, and most preferably no less than 10 -2 S/cm. The disclosed lithium battery can be a lithium-ion battery or a lithium metal battery, the latter having lithium metal as the primary anode active material. The lithium metal battery can have lithium metal implemented at the anode when the cell is made. Alternatively, the lithium may be stored in the cathode active material and the anode side is lithium metal-free initially. This is called an anode-less lithium metal battery. As illustrated in FIG. 2(A), the anode-less lithium cell is in an as-manufactured or fully discharged state according to certain embodiments of the present disclosure. The cell comprises an anode current collector 12 (e.g., Cu foil), a separator, a cathode layer 16 comprising a cathode active material, an optional conductive additive (not shown), an optional resin binder (not shown), and an electrolyte (dispersed in the entire cathode layer and in contact with the cathode active material), and a cathode current collector 18 that supports the cathode layer 16. There is no lithium metal in the anode side when the cell is manufactured. In a charged state, as illustrated in FIG. 2(B), the cell comprises an anode current collector 12, lithium metal 20 plated on a surface (or two surfaces) of the anode current collector 12 (e.g., Cu foil), a separator 15, a cathode layer 16, and a cathode current collector 18 supporting the cathode layer. The lithium metal comes from the cathode active material (e.g., LiCoO 2 and LiMn 2 O 4 ) that contains Li element when the cathode is made. During a charging step, lithium ions are released from the cathode active material and move to the anode side to deposit onto a surface or both surfaces of an anode current collector. One unique feature of the presently disclosed anode-less lithium cell is the notion that there is substantially no anode active material and no lithium metal is present when the battery cell is made. The commonly used anode active material, such as an intercalation type anode material (e.g., graphite, carbon particles, Si, SiO, Sn, SnO 2 , Ge, etc.), P, or any conversion-type anode material, is not included in the cell. The anode only contains a current collector or a protected current collector. No lithium metal (e.g., Li particle, surface-stabilized Li particle, Li foil, Li chip, etc.) is present in the anode when the cell is made; lithium is basically stored in the cathode (e.g., Li element in LiCoO 2 , LiMn2O 4 , lithium iron phosphate, lithium polysulfides, lithium polyselenides, etc.). During the first charge procedure after the cell is sealed in a housing (e.g., a stainless steel hollow cylinder or an Al/plastic laminated envelop), lithium ions are released from these Li-containing compounds (cathode active materials) in the cathode, travel through the electrolyte/separator into the anode side, and get deposited on the surfaces of an anode current collector. During a subsequent discharge procedure, lithium ions leave these surfaces and travel back to the cathode, intercalating or inserting into the cathode active material. Such an anode-less cell is much simpler and more cost-effective to produce since there is no need to have a layer of anode active material (e.g., graphite particles, along with a conductive additive and a binder) pre-coated on the Cu foil surfaces via the conventional slurry coating and drying procedures. The anode materials and anode active layer manufacturing costs can be saved. Furthermore, since there is no anode active material layer (otherwise typically 40-200 µm thick), the weight and volume of the cell can be significantly reduced, thereby increasing the gravimetric and volumetric energy density of the cell. Another important advantage of the anode-less cell is the notion that there is no lithium metal in the anode when a lithium metal cell is made. Lithium metal (e.g., Li metal foil and particles) is highly sensitive to air moisture and oxygen and notoriously known for its difficulty and danger to handle during manufacturing of a Li metal cell. The manufacturing facilities should be equipped with special class of dry rooms, which are expensive and significantly increase the battery cell costs. The anode current collector may be selected from a foil, perforated sheet, or foam of Cu, Ni, stainless steel, Al, graphene, graphite, graphene-coated metal, graphite-coated metal, carbon- coated metal, or a combination thereof. Preferably, the current collector is a Cu foil, Ni foil, stainless steel foil, graphene-coated Al foil, graphite-coated Al foil, or carbon-coated Al foil. The anode current collector typically has two primary surfaces. Preferably, one or both of these primary surfaces is deposited with multiple particles or coating of a lithium-attracting metal (lithiophilic metal), wherein the lithium-attracting metal, preferably having a diameter or thickness from 1 nm to 10 μm, is selected from Au, Ag, Mg, Zn, Ti, K, Al, Fe, Mn, Co, Ni, Sn, V, Cr, an alloy thereof, or a combination thereof. This deposited metal layer may be further deposited with a layer of graphene that covers and protects the multiple particles or coating of the lithiophilic metal. The graphene layer may comprise graphene sheets selected from single-layer or few- layer graphene, wherein the few-layer graphene sheets are commonly defined to have 2-10 layers of stacked graphene planes having an inter-plane spacing d002 from 0.3354 nm to 0.6 nm as measured by X-ray diffraction. The single-layer or few-layer graphene sheets may contain a pristine graphene material having essentially zero % of non-carbon elements, or a non-pristine graphene material having 0.001% to 45% by weight of non-carbon elements. The non-pristine graphene may be selected from graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrogenated graphene, doped graphene, chemically functionalized graphene, or a combination thereof. The graphene layer may comprise graphene balls and/or graphene foam. Preferably, the graphene layer has a thickness from 1 nm to 50 µm and/or has a specific surface area from 5 to 1000 m 2 /g (more preferably from 10 to 500 m 2 /g). For a lithium-ion battery featuring the presently disclosed electrolyte, there is no particular restriction on the selection of an anode active material. The anode active material may be selected from the group consisting of: (a) silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), phosphorus (P), bismuth (Bi), zinc (Zn), aluminum (Al), titanium (Ti), nickel (Ni), cobalt (Co), and cadmium (Cd); (b) alloys or intermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Ni, Co, or Cd with other elements; (c) oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Fe, Ni, Co, V, or Cd, and their mixtures, composites, or lithium-containing composites; (d) salts and hydroxides of Sn; (e) lithium titanate, lithium manganate, lithium aluminate, lithium titanium niobate, lithium- containing titanium oxide, lithium transition metal oxide, ZnCo 2 O 4 ; (f) carbon or graphite particles (g) prelithiated versions thereof; and (h) combinations thereof. Another surprising and of tremendous scientific and technological significance is our discovery that the flammability of any volatile organic solvent can be effectively suppressed provided that a sufficiently high amount of a lithium salt and polymer is added to and dissolved in this organic solvent to form a solid-like or quasi-solid electrolyte (e.g., first electrolyte in the cathode). In general, such a quasi-solid electrolyte exhibits a vapor pressure less than 0.01 kPa and often less than 0.001 kPa (when measured at 20°C) and less than 0.1 kPa and often less than 0.01 kPa (when measured at 100°C). (The vapor pressures of the corresponding neat solvent, without any lithium salt dissolved therein, are typically significantly higher.) In many cases, the vapor molecules are practically too few to be detected. A highly significant observation is that the polymer derived (polymerized) from a phosphazene compound can dramatically curtail the amount of volatile solvent molecules that can escape into the vapor phase in a thermodynamic equilibrium condition. In many cases, this has effectively prevented any flammable gas molecules from initiating a flame even at an extremely high temperature. The flash point of the quasi-solid or solid-state electrolyte is typically at least 100 degrees (often > 150 degrees) higher than the flash point of the neat organic solvent without polymerization. In most of the cases, either the flash point is significantly higher than 200°C or no flash point can be detected. The electrolyte just would not catch on fire. Furthermore, any accidentally initiated flame does not sustain for longer than 3 seconds. This is a highly significant discovery, considering the notion that fire and explosion concern has been a major impediment to widespread acceptance of battery-powered electric vehicles. This new technology could significantly impact the emergence of a vibrant EV industry. In addition to the non-flammability and high lithium ion transference numbers, there are several additional benefits associated with using the presently disclosed quasi-solid or solid-state electrolytes. As one example, these electrolytes can significantly enhance cycling and safety performance of rechargeable lithium batteries through effective suppression of lithium dendrite growth. Due to a good contact between the electrolyte and an electrode, the interfacial impedance can be significantly reduced. Additionally, the local high viscosity induced by presence of a polymer can increase the pressure from the electrolyte to inhibit dendrite growth, potentially resulting in a more uniform deposition of lithium ions on the surface of the anode. The high viscosity could also limit anion convection near the deposition area, promoting more uniform deposition of Li ions. These reasons, separately or in combination, are believed to be responsible for the notion that no dendrite-like feature has been observed with any of the large number of rechargeable lithium cells that we have investigated thus far. As another benefit example, this electrolyte is capable of inhibiting lithium polysulfide dissolution at the cathode and migration to the anode of a Li-S cell, thus overcoming the polysulfide shuttle phenomenon and allowing the cell capacity not to decay significantly with time. Consequently, a coulombic efficiency nearing 100% along with long cycle life can be achieved. When a concentrated electrolyte and a crosslinked polymer is used, the solubility of lithium polysulfide will be reduced significantly. The lithium salt dispersed in the polymer electrolyte may comprise an ionic liquid lithium salt, or a combination thereof. The ionic liquid is composed of ions only. Ionic liquids are low melting temperature salts that are in a molten or liquid state when above a desired temperature. For instance, an ionic salt is considered as an ionic liquid if its melting point is below 100°C. If the melting temperature is equal to or lower than room temperature (25ºC), the salt is referred to as a room temperature ionic liquid (RTIL). The IL-based lithium salts are characterized by weak interactions, due to the combination of a large cation and a charge-delocalized anion. This results in a low tendency to crystallize due to flexibility (anion) and asymmetry (cation). Some ILs may be used as a co-solvent (not as a salt) to work with the first organic solvent of the present disclosure. A well-known ionic liquid is formed by the combination of a 1-ethyl-3- methyl-imidazolium (EMI) cation and an N,N-bis(trifluoromethane)sulphonamide (TFSI) anion. This combination gives a fluid with an ionic conductivity comparable to many organic electrolyte solutions, a low decomposition propensity and low vapor pressure up to ~300-400°C. This implies a generally low volatility and non-flammability and, hence, a much safer electrolyte solvent for batteries. Ionic liquids are basically composed of organic or inorganic ions that come in an unlimited number of structural variations owing to the preparation ease of a large variety of their components. Thus, various kinds of salts can be used to design the ionic liquid that has the desired properties for a given application. These include, among others, imidazolium, pyrrolidinium and quaternary ammonium salts as cations and bis(trifluoromethanesulphonyl) imide, bis(fluorosulphonyl)imide and hexafluorophosphate as anions. Useful ionic liquid-based lithium salts (not solvent) may be composed of lithium ions as the cation and bis(trifluoromethanesulphonyl)imide, bis(fluorosulphonyl)imide and hexafluorophosphate as anions. For instance, lithium trifluoromethanesulfonimide (LiTFSI) is a particularly useful lithium salt. Based on their compositions, ionic liquids come in different classes that include three basic types: aprotic, protic and zwitterionic types, each one suitable for a specific application. Common cations of room temperature ionic liquids (RTILs) include, but are not limited to, tetraalkylammonium, di, tri, and tetra-alkylimidazolium, alkylpyridinium, dialkyl-pyrrolidinium, dialkylpiperidinium, tetraalkylphosphonium, and trialkylsulfonium. Common anions of RTILs include, but are not limited to, BF 4 -, B(CN) 4 -, CH 3 BF 3 -, CH 2 CHBF 3 -, CF 3 BF 3 -, C 2 F 5 BF 3 -, n- C 3 F 7 BF 3 -, n-C 4 F 9 BF 3 -, PF 6 -, CF 3 CO 2 -, CF 3 SO 3 -, N(SO 2 CF 3 ) 2 -, N(COCF 3 )(SO 2 CF 3 )-, N(SO 2 F) 2 -, N(CN) 2 -, C(CN) 3 -, SCN-, SeCN-, CuCl 2 -, AlCl4-, F(HF) 2.3 -, etc. Relatively speaking, the combination of imidazolium- or sulfonium-based cations and complex halide anions such as AlCl 4 -, BF 4 -, CF 3 CO 2 -, CF 3 SO 3 -, NTf 2 -, N(SO 2 F) 2 -, or F(HF) 2.3 - results in RTILs with good working conductivities. RTILs can possess archetypical properties such as high intrinsic ionic conductivity, high thermal stability, low volatility, low (practically zero) vapor pressure, non-flammability, the ability to remain liquid at a wide range of temperatures above and below room temperature, high polarity, high viscosity, and wide electrochemical windows. These properties, except for the high viscosity, are desirable attributes when it comes to using an RTIL as an electrolyte co-solvent in a rechargeable lithium cell. There is also no restriction on the type of the cathode materials that can be used in practicing the present disclosure. For Li-S cells, the cathode active material may contain lithium polysulfide or sulfur. If the cathode active material includes lithium-containing species (e.g., lithium polysulfide) when the cell is made, there is no need to have a lithium metal pre- implemented in the anode. There are no particular restrictions on the types of cathode active materials that can be used in the presently disclosed lithium battery, which can be a primary battery or a secondary battery. The rechargeable lithium metal or lithium-ion cell may preferably contain a cathode active material selected from, as examples, a layered compound LiMO 2 , spinel compound LiM 2 O 4 , olivine compound LiMPO 4 , silicate compound Li 2 MSiO 4 , Tavorite compound LiMPO 4 F, borate compound LiMBO 3 , or a combination thereof, wherein M is a transition metal or a mixture of multiple transition metals. In a rechargeable lithium cell, the cathode active material may be selected from a metal oxide, a metal oxide-free inorganic material, an organic material, a polymeric material, sulfur, lithium polysulfide, selenium, or a combination thereof. The metal oxide-free inorganic material may be selected from a transition metal fluoride, a transition metal chloride, a transition metal dichalcogenide, a transition metal trichalcogenide, or a combination thereof. In a particularly useful embodiment, the cathode active material is selected from FeF 3 , FeCl 3 , CuCl 2 , TiS2, TaS2, MoS 2 , NbSe 3 , MnO 2 , CoO 2 , an iron oxide, a vanadium oxide, or a combination thereof, if the anode contains lithium metal as the anode active material. The vanadium oxide may be preferably selected from the group consisting of VO 2 , LixVO 2 , V 2 O 5 , Lix V 2 O 5 , V 3 O8, LixV 3 O 8 , Li x V 3 O 7 , V 4 O 9 , Li x V 4 O 9 , V 6 O 13 , Li x V 6 O 13 , their doped versions, their derivatives, and combinations thereof, wherein 0.1 < x < 5. For those cathode active materials containing no Li element therein, there should be a lithium source implemented in the cathode side to begin with. This can be any compound that contains a high lithium content, or a lithium metal alloy, etc. In a rechargeable lithium cell (e.g., the lithium-ion battery cell), the cathode active material may be selected to contain a layered compound LiMO 2 , spinel compound LiM 2 O 4 , olivine compound LiMPO 4 , silicate compound Li 2 MSiO 4 , Tavorite compound LiMPO 4 F, borate compound LiMBO 3 , or a combination thereof, wherein M is a transition metal or a mixture of multiple transition metals. Particularly desirable cathode active materials comprise lithium nickel manganese oxide (LiNi a Mn 2-a O 4 , 0<a<2), lithium nickel manganese cobalt oxide (LiNi n Mn m Co 1-n-m O 2 , 0<n<1, 0<m<1, n+m<1), lithium nickel cobalt aluminum oxide (LiNi c Co d Al 1-c-d O 2 , 0<c<1, 0<d<1, c+d<1), lithium manganate (LiMn2O 4 ), lithium iron phosphate (LiFePO 4 ), lithium manganese oxide (LiMnO 2 ), lithium cobalt oxide (LiCoO 2 ), lithium nickel cobalt oxide (LiNi p Co 1-p O 2 , 0<p<1), or lithium nickel manganese oxide (LiNi q Mn 2-q O 4 , 0<q<2). In a preferred lithium metal secondary cell, the cathode active material preferably contains an inorganic material selected from: (a) bismuth selenide or bismuth telluride, (b) transition metal dichalcogenide or trichalcogenide, (c) sulfide, selenide, or telluride of niobium, zirconium, molybdenum, hafnium, tantalum, tungsten, titanium, cobalt, manganese, iron, nickel, or a transition metal; (d) boron nitride, or (e) a combination thereof. Again, for those cathode active materials containing no Li element therein, there should be a lithium source implemented in the cathode side to begin with. In another preferred rechargeable lithium cell (e.g., a lithium metal secondary cell or a lithium-ion cell), the cathode active material contains an organic material or polymeric material selected from Poly(anthraquinonyl sulfide) (PAQS), lithium oxocarbons (including squarate, croconate, and rhodizonate lithium salts), oxacarbon (including quinines, acid anhydride, and nitrocompound), 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA), poly(anthraquinonyl sulfide), pyrene-4,5,9,10-tetraone (PYT), polymer-bound PYT, Quino(triazene), redox-active organic material (redox-active structures based on multiple adjacent carbonyl groups (e.g., “C 6 O 6 ”-type structure, oxocarbons), Tetracyanoquinodimethane (TCNQ), tetracyanoethylene (TCNE), 2,3,6,7,10,11-hexamethoxytriphenylene (HMTP), poly(5-amino-1,4-dyhydroxy anthraquinone) (PADAQ), phosphazene disulfide polymer ([(NPS2) 3 ]n), lithiated 1,4,5,8– naphthalenetetraol formaldehyde polymer, Hexaazatrinaphtylene (HATN), Hexaazatriphenylene hexacarbonitrile (HAT(CN)6), 5-Benzylidene hydantoin, Isatine lithium salt, Pyromellitic diimide lithium salt, tetrahydroxy-p-benzoquinone derivatives (THQLi4), N,N’-diphenyl-2,3,5,6- tetraketopiperazine (PHP), N,N’-diallyl-2,3,5,6-tetraketopiperazine (AP), N,N’-dipropyl-2,3,5,6- tetraketopiperazine (PRP), a thioether polymer, a quinone compound, 1,4-benzoquinone, 5,7,12,14-pentacenetetrone (PT), 5-amino-2,3-dihydro-1,4-dyhydroxy anthraquinone (ADDAQ), 5-amino-1,4-dyhydroxy anthraquinone (ADAQ), calixquinone, Li4C 6 O 6 , Li 2 C 6 O 6 , Li 6 C 6 O 6 , or a combination thereof. The thioether polymer may be selected from Poly[methanetetryl-tetra(thiomethylene)] (PMTTM), Poly(2,4-dithiopentanylene) (PDTP), or Poly(ethene-1,1,2,2-tetrathiol) (PETT) as a main-chain thioether polymer, in which sulfur atoms link carbon atoms to form a polymeric backbones. The side-chain thioether polymers have polymeric main-chains that consist of conjugating aromatic moieties, but having thioether side chains as pendants. Among them Poly(2-phenyl-1,3-dithiolane) (PPDT), Poly(1,4-di(1,3-dithiolan-2-yl)benzene) (PDDTB), poly(tetrahydrobenzodithiophene) (PTHBDT), and poly[1,2,4,5-tetrakis(propylthio)benzene] (PTKPTB) have a polyphenylene main chain, linking thiolane on benzene moieties as pendants. Similarly, poly[3,4(ethylenedithio)thiophene] (PEDTT) has polythiophene backbone, linking cyclo-thiolane on the 3,4- position of the thiophene ring. In yet another preferred rechargeable lithium cell, the cathode active material contains a phthalocyanine compound selected from copper phthalocyanine, zinc phthalocyanine, tin phthalocyanine, iron phthalocyanine, lead phthalocyanine, nickel phthalocyanine, vanadyl phthalocyanine, fluorochromium phthalocyanine, magnesium phthalocyanine, manganous phthalocyanine, dilithium phthalocyanine, aluminum phthalocyanine chloride, cadmium phthalocyanine, chlorogallium phthalocyanine, cobalt phthalocyanine, silver phthalocyanine, a metal-free phthalocyanine, a chemical derivative thereof, or a combination thereof. This class of lithium secondary batteries has a high capacity and high energy density. Again, for those cathode active materials containing no Li element therein, there should be a lithium source implemented in the cathode side to begin with. As illustrated in FIG. 1(B), the present disclosure also provides an electrolyte composition comprising: (a) a first solution, comprising at least a phosphazene compound (e.g. a monomer, oligomer, or reactive polymer) in a liquid state or dissolved in a first non-aqueous solvent; and (b) a second solution, comprising a curing agent (e.g., an initiator, a substituent, and/or a crosslinking agent), a lithium salt, and a second non-aqueous liquid solvent (e.g., an organic solvent or ionic liquid solvent); wherein the first solution and the second solution are stored separately before the first solution and the second solution are mixed to form the electrolyte. Actually, the lithium salt may be dissolved in the first solvent, the second solvent, or both. The disclosure further provides a method of producing a rechargeable lithium cell (as illustrated in FIG. 1(A)), the method comprising: (a) providing a cathode; (b) providing an anode; (c) combining the cathode and the anode to form a dry cell; and (d) introducing (e.g., injecting) the presently disclosed reactive electrolyte composition into the dry cell and curing (polymerizing, substituting, and/or crosslinking) the reactive electrolyte composition to produce the rechargeable lithium cell. Step (d) may comprise partially or totally removing any un- polymerized or residual liquid solvent. In this method, step (a) may be selected from any commonly used cathode production process. For instance, the process may include (i) mixing particles of a cathode active material, a conductive additive, an optional resin binder, optional particles of a solid inorganic electrolyte powder, and an optional flame retardant in a liquid medium (e.g., an organic solvent, such as NMP) to form a slurry; and (ii) coating the slurry on a cathode current collector (e.g., an Al foil) and removing the solvent. The anode in step (b) may be produced in a similar manner, but using particles of an anode active material (e.g., particles of Si, SiO, Sn, SnO 2 , graphite, and carbon). The liquid medium used in the production of an anode may be water or an organic solvent. Step (c) may entail combining the anode, a porous separator, the cathode, along with their respective current collectors, to form a unit cell which is enclosed in a protective housing to form a dry cell. As illustrated in FIG. 1(C), the disclosure also provides a method of producing the disclosed rechargeable lithium cell, the method comprising: (A) mixing particles of a cathode active material, an optional conductive additive (typically required in the cathode), an optional binder (optional but not required since, upon polymerization and/or crosslinking, the reactive additive becomes a binder that bonds the solid particles in the electrode together), an optional flame retardant, optional particles of an inorganic solid electrolyte powder, a reactive additive, and a lithium salt to form a cathode, wherein the reactive additive comprises at least a reactive phosphazene compound and a curing agent; (B) providing an anode; (C) combining the cathode and the anode to form a cell; and (D) polymerizing and/or crosslinking the reactive additive, prior to or after step (C), to produce the rechargeable lithium cell. In step (A), particles of a cathode active material, an optional conductive additive, an optional binder, an optional flame retardant, a lithium salt, and optional particles of an inorganic solid electrolyte powder may be dissolved or dispersed in a reactive additive (containing at least a phosphazene compound) to form a slurry. The slurry is attached to or coated on a primary surface or both primary surfaces of a cathode current collector (e.g., Al foil) to form a cathode. In certain embodiments, step (B) comprises a procedure of mixing particles of an anode active material, an optional conductive additive (not required if the anode active material is a carbon or graphite material), an optional binder (not required since, upon polymerization and/or crosslinking, the reactive additive becomes a binder that bonds the solid particles in the electrode together), an optional flame retardant, optional particles of an inorganic solid electrolyte powder, a reactive additive (the same or different reactive as used in the cathode, and a lithium salt to form an anode. The method may further comprise polymerizing and/or crosslinking the reactive additive, prior to or after step (C), to produce the rechargeable lithium cell. Although FIG. 1(C) indicates that curing occurs after the cell is made according to certain embodiments of the present disclosure, curing of the reactive electrolyte composition can occur right after the electrode (anode or cathode) is made. In some embodiments, step (A) further comprises adding particles of an inorganic solid electrolyte powder in the cathode. Step (B) may further comprise adding particles of an inorganic solid electrolyte powder in the anode. Illustrated in FIG. 1(D) is yet another embodiment of the present disclosure, which is a method of producing the disclosed rechargeable lithium cell. The method comprises: (A) mixing particles of a cathode active material, an optional conductive additive (typically required in the cathode), an optional binder (not required since the reactive additive becomes a binder upon polymerization and/or crosslinking), an optional flame retardant, optional particles of an inorganic solid electrolyte powder, and a reactive additive to form a cathode (preferably containing at least one cathode active material layer supported on a current collector), wherein the reactive additive comprises at least a phosphazene compound in a liquid form or dissolved in in a first liquid solvent; (B) providing an anode; (C) combining the cathode, an optional separator, the anode, and a protective housing to form a cell; and (D) injecting a liquid mixture of a lithium salt, a curing agent, an optional flame retardant (if in a liquid state) and a second non-aqueous liquid solvent into the cell and polymerizing and/or crosslinking the reactive additive (via heat, UV, electron beam, or other high-energy radiation) to produce the rechargeable lithium cell. This may be followed by a step of partially or totally removing any un- polymerized solvent. For the production of a lithium-ion cell, step (B) may comprise mixing particles of an anode material (e.g., Si, SiO, graphite, carbon particles, etc.), an optional conductive additive, an optional binder, an optional flame retardant, optional particles of an inorganic solid electrolyte powder, and a reactive additive (comprising a reactive phosphazene compound) to form at least one anode active layer supported on an anode current collector (e.g., Cu foil). The following examples are presented primarily for the purpose of illustrating the best mode practice of the present disclosure, not to be construed as limiting the scope of the present disclosure. EXAMPLE 1: Solid electrolyte based on the general formula [-NP(A)a(B)b-] x In a representative procedure, a 1-liter flask equipped with a thermometer, a stirrer, a dropping funnel and a condenser was charged with 58.0 g (0.167 mole) of hexachlorotriphosphazene, 50 ml of toluene and 158 g (2.0 moles) of pyridine, and the mixture was stirred. To the mixture was dropwise added 143 g (1.1 moles) of 2-hydroxyethyl methacrylate (HEMA) through the dropping funnel. The mixture was heated to 60°C and the reaction was continued for 8 hours with stirring. After precipitated crystalline materials were filtered off, the solvent in the filtrate was distilled off under reduced pressures. The residual solution was dried to a desired level, leaving 136 g (yield: 91%) of a curable phosphazene compound in the form of a solution having a yellow color. A benzol peroxide initiator (0.5% by weight) was added to the curable phosphazene compound in toluene to produce solution No. 1. A lithium salt, lithium hexafluorophosphate (LiPF 6 ), was dissolved in fluoroethylene carbonate (FEC) to form a 1.0 M solution (Solution No. 2). The lithium salt amount was varied to result in a final lithium salt-to-polyphophazene ratio from 5/100 to 25/100. Solution No. 1 and Solution No. 2 were then mixed, well stirred, and injected into a dry battery cell. Most of the solvents were removed with the assistance of a vacuum pump. The resin was cured at 60°C overnight. Two types of battery cells were studied in this example: a lithium/NCM-532 cell (initially the cell being lithium-free) and lithium-ion cell containing a Si-based anode and a NCM-532 cathode. EXAMPLE 2: Solid electrolyte based on the general formula [-NP(A)a(B)b-] x A 1-liter flask equipped with a thermometer, a stirrer, a dropping funnel and a condenser was charged with 100 ml of tetrahydrofuran and 11.6 g (0.5 mole) of metallic sodium. To this mixture was dropwise added 55.5 g (0.55 mole) of 2,2,2-trifluoroethanol, and the mixture was then reacted under reflux until sodium was completely consumed. To this reaction mixture was dropwise added a solution of 39.6 g (0.111 mole) of hexachlorotriphosphazene in 100 ml of toluene, and the mixture was reacted under reflux for 2 hours. Thereafter, the temperature of the reaction mixture was dropped to room temperature and 191 g (1.47 mole) of HEMA was dropwise added to the reaction mixture slowly using the dropping funnel. The mixture was then heated to 60°C and the reaction was continued for 8 hours at that temperature with stirring. Thereafter, precipitated crystalline materials and the catalyst were filtered off and the solvent in the filtrate was distilled off under reduced pressure. The residual solution was dried to a sufficient level, leaving 88 g (yield: 93%) of a curable phosphazene compound in the form of a solution having a yellow color. A benzol peroxide initiator (0.5% by weight), lithium bis(oxalato)borate (LiBOB), and curable phosphazene compound (ratio of 0.5/10/100) were dispersed in a mixture of vinylene carbonate (VC) and toluene to form a 1.0 M solution. The solution was injected into a dry battery cell. Most (>80%) of the solvents were removed with the assistance of a vacuum pump. The resin was cured at 65°C overnight. Two types of battery cells were studied in this example: a lithium/NCM-811 cell (initially the cell being lithium-free) and lithium-ion cell containing a Si- based anode and a NCA cathode. EXAMPLE 3: Solid electrolyte based on Poly[bis(2-hydroxyethyl-methacrylate)-phosphazene] and poly[(2-hydroxyethyl-methacrylate)-graft-poly(lactic-acid)-p hosphazene] Poly[bis(2-hydroxyethyl-methacrylate)-phosphazene] was obtained by nucleophilic condensation reactions at different concentrations of the substituents. Specifically, the scheme of the poly(organophosphazenes) synthesis by nucleophilic substitution is shown in Reaction 1 earlier. The single substituted and co-substituted poly(dichlorophosphazenes) (PZs) were obtained from poly(dichlorophosphazene) by melt ring-opening polymerization of hexachlorocyclotriphosphazene (HCCP) under vacuum at 250°C for 3 h. After this time, the polymer was dissolved at room temperature in anhydrous THF, and it was separated by precipitation into n-heptane. The substitution of poly(dichlorophosphazene) (PZ) with pentaerythritol triacrylate (PEATA) was made at two molar ratios: 1 : 3 and 1:6 mmol PZ-PEATA. Triethylamine (TEA) was added at 1 : 1 mmol ratio PEATA: TEA as effective acceptor to trap hydrogen chloride. The PZ was dissolved in THF (10 mL) under stirring, after 10min PEATA and TEA were added and the glass vial reactor was kept for two days at room temperature. The product was purified following the procedure described for PZ; the yield was 51%. A methyl amine initiator (0.5% by weight), lithium bis(oxalato)borate (LiBOB), and curable phosphazene compound (ratio of 0.5/10/100) were dispersed in a mixture of vinylene carbonate (VC) and toluene to form a 1.0 M solution. The solution was injected into a dry battery cell. Most (>80%) of the solvents were removed with the assistance of a vacuum pump. The resin was cured at 65°C overnight. Two types of battery cells were studied in this example: a lithium/NCM-811 cell (initially the cell being lithium-free) and lithium-ion cell containing a graphite-based anode and a NCM-622 cathode. EXAMPLE 4: 2,2,4,4,6,6-Hexakis(vinyloxyethylenoxy)-2,2,4,4,6,6-hexahydr o-1,3,5,2,4,6- triazatriphosphorine The compound 2,2,4,4,6,6-Hexakis(vinyloxyethylenoxy)-2,2,4,4,6,6-hexahydr o- 1,3,5,2,4,6- triazatriphosphorine is prepared by the following reactions: w here R = the following structure: In a representative procedure, 16.80 g (0.10 mole) of sodium hydride (95%) was suspended in 700 ml of anhydrous THF and/or argon in a 2-liter three-necked flask with internal thermometer, dropping funnel, and reflux condenser. While cooling in an ice bath, 61.67 g (0.70 mole) of ethylene glycol mono-vinyl ether was then added slowly through a dropping funnel over a period of 90 min. Stirring was then continued at about 50°C for a total of 20 h. The contents of the flask gradually exhibited a brown color. Subsequently, a solution of 34.79 g (0.10) mole of phosphonitrile chloride (NPCl 2 ) 3 in 200 ml of anhydrous THF was added slowly (90 min) through a dropping funnel. Water bath cooling was necessary during this addition to keep the temperature below 30°C. Stirring was continued for 1 h at room temperature, and the batch was then heated to an internal temperature of 50°C. Stirring was continued overnight (total 24 h) at this temperature. The mixture was then allowed to cool to room temperature and was filtered by suction. Almost all of the THF was removed from the brown filtrate in a rotary evaporator; 250 ml of diethyl ether and 250 ml of deionized water were added, and the mixture was transferred to a separatory funnel. The ether phase was separated, and the aqueous phase was extracted two more times with 125 ml portions of diethyl ether. The combined ether phases were shaken three times with 50 ml portions of deionized water, which can lighten the mixture considerably. The ether phase was separated and dried over sodium sulfate. After filtering off the drying agent and evaporating the solvent in a rotary evaporator, 62.84 g (0.096 mole, corresponding to 96% of the theoretical amount) of a clear yellow liquid was obtained. The product may be further purified if so desired. The product is readily soluble in chloroform, tetrahydrofuran, diethyl ether, isopropanol, ethyl acetate, and toluene. The phosphazene derivatives herein produced, along with a lithium salt (e.g. 10% lithium borofluoride (LiBF 4 ) or lithium trifluoro-methanesulfonate (LiCF 3 SO 3 )) were then dissolved in solvents, such as ethyl acetate (EA), fluoroethylene carbonate (FEC), and hydrofluoroether (HFE), to produce precursor or reactive liquid electrolyte compositions. The lithium-ion cells prepared in this example comprise an anode of meso-carbon micro- beads (MCMB, an artificial graphite), a cathode of NCM-622 particles, and a porous PE/PP membrane as a separator. The reactive liquid electrolyte compositions were injected into dry battery cells at 45°C, allowing the electrolyte to fully permeate into both the anode and the cathode to wet out the surfaces of anode and cathode active materials. The cells were then irradiated with electron beam at room temperature until a total dosage of 40 Gy was reached. In- situ crosslinking of the polyphosphazene polymer in the battery cell was accomplished. Crosslinked networks are capable of holding any liquid electrolyte in place, preventing any leakage issue. Additionally, polymer films were cast on a glass surface and some of the films were subjected to the same dosage of electron beams. The room temperature lithium-ion conductivity values of the polymers (each containing approximately 10% by weight lithium salt, LiBF 4 ) were increased from approximately 3.8 × 10 −4 S/cm for un-crosslinked polymer to approximately 2.6 × 10 −3 S/cm for electron beam-cured polymers. Electrochemical measurements (CV curves) were carried out in an electrochemical workstation at a scanning rate of 1-100 mV/s. The electrochemical performance of the cells was evaluated by galvanostatic charge/discharge cycling at a current density of 50-500 mA/g using an Arbin electrochemical workstation. Testing results indicate that the cells containing quasi- solid or solid-state electrolytes obtained by in situ curing perform very well in terms of cycling stability and the energy storage capacity and yet these cells are flame resistant and relatively safe. EXAMPLE 5: Electrolytes containing homo-polymers and copolymers from vinyl ether phosphazene derivatives Flame-resistant electrolyte compositions (liquid solutions), quasi-solid electrolytes, and solid-state electrolytes are prepared from vinyl ether phosphazene derivative with mixed substitution, which were prepared according to the following reactions:
In a representative procedure, 9.60 g (0.40 mole) of sodium hydride was placed in a 1000-ml three-necked flask with KPG stirrer, dropping funnel, and internal thermometer, and was slurred with 100 ml of anhydrous tetrahydrofuran. While cooling with ice/salt, a solution of 65.68 g (0.40 mole) of eugenol in 50 ml of anhydrous tetrahydrofuran (THF) was then added dropwise (gas evolution, addition time 45 min). Stirring was continued for 1 h at room temperature, and then a solution of 46.36 g (0.133 mole) of (NPCl 2 ) 3 in 150 ml of anhydrous THF was added. The mixture was stirred for 60 h at room temperature, transferred to a single-necked flask, and the solvent is evaporated by rotation. The product was taken up in 150 ml of diethyl ether and 150 ml of deionized water, and the phases were separated in a separatory funnel. The aqueous phase was washed twice with 10 ml portions of deionized water. The combined orange- colored ether phases were dried over anhydrous sodium sulfate. The drying agent was filtered off and the clear filtrate was stirred for 30 min at room temperature with activated charcoal. After repeated filtration and solvent removal by rotary evaporation, 94.94 g (0.130 mole, corresponding to 98% of the theoretical amount) of a viscous, clear, brown-colored liquid was obtained. The product may be further filtered through a short silica gel column if so desired. The product has a molecular weight 730.89 g/mole and is readily soluble in toluene, chloroform, ethyl acetate, diethyl ether, tetrahydrofuran, and acetone, etc. The vinyl ether phosphazene derivatives herein produced, along with a lithium salt (e.g. 10% lithium borofluoride (LiBF 4 )), were then dissolved in solvents, such as ethyl acetate (EA), fluoroethylene carbonate (FEC), and hydrofluoroether (HFE), to produce precursor or reactive electrolyte compositions. The lithium-ion cells prepared in this example comprise an anode of graphene-protected Si particles, a cathode of NCM-622 particles, and a porous PE/PP membrane as a separator. In several samples, a garnet-type solid electrolyte (Li 7 La 3 Zr 2 O 12 (LLZO) powder) was added into the cathode (NCM-532) in the anode-less lithium battery. EXAMPLE 6: Cathode and anode layers containing a quasi-solid or solid-state electrolyte Electrode layers comprising particles of anode active materials (e.g. MCMB particles) in the anode and cathode active materials (e.g. LiCoO 2 particles in the cathode) in contact with a polyphosphazene electrolyte were prepared from [NPCl 2 ] n and a propylene oxide oligomer according to the following reaction: In a representative procedure, 4.69 g of [NPCl 2 ] n were dissolved in 200 ml of anhydrous THF to form a polymer solution. Then, 11.3 ml of triethyl amine (TEA) and 50 ml of propylene oxide oligomer were then added to the polymer solution. The resulting reaction mixture was stirred for 24 h at room temperature. The solvent was then removed under vacuum yielding a highly viscous yellowish polymer solution which was dialyzed against water for 5 days. Removal of water after dialysis yielded a slightly yellowish, highly viscous polymer. The substituted polyphosphazene, 15% by weight of lithium hexafluorophosphate (LiPF 6 ), and 0.5% by weight of benzophenone as photoinitiator were then dispersed/dissolved in a 50/50 solvent mixture of fluoroethylene carbonate (FEC) and vinylene carbonate (VC) to form a solution. After stirring at room temperature for 1 hour, the solution was added with LiCoO 2 particles and 7% by weight carbon black (Super-P) to form a reactive slurry. The slurry was coated on a surface of Al foil to form a layer of cathode, which was exposed to UV light for 20 minutes to induce crosslinking reaction. A layer of anode was prepared in a similar manner, but the electrode active material was MCMB particles. The anode layer was coated on a Cu foil surface to make an anode electrode. The anode layer was also exposed to UV light to initiate the crosslinking reaction. In a separate experiment, a separator membrane was prepared by replacing the electrode active material with 25% by weight of a garnet-type solid electrolyte powder, Li 7 La 3 Zr 2 O 12 (LLZO), which was mixed with the reactive slurry containing the polymer, the lithium salt, the photoinitiator, but no carbon black, in the solvent. This reactive slurry was cast on a glass surface to obtain a separator layer, which was then peeled off from the glass to obtain a free-standing separator layer. The anode, separator, and cathode layers were then stacked together and encased by a protective housing to make a battery cell. Electrochemical measurements (CV curves) were carried out in an electrochemical workstation at a scanning rate of 1-100 mV/s. The electrochemical performance of the cells was evaluated by galvanostatic charge/discharge cycling at a current density of 50-500 mA/g using an Arbin electrochemical workstation. Testing results indicate that the cells containing quasi- solid or solid-state electrolytes obtained by in situ curing perform very well. These cells are flame resistant and relatively safe.