Polymer composite separator for a lithium secondary battery and manufacturing method

1 . A flame-resistant polymer composite separator for use in a lithium battery, wherein the polymer composite separator comprises (a) a binder or matrix polymer; (b) 0.1% to 50% by weight of a lithium salt dispersed in the polymer; and (c) from 30% to 99% by weight of particles or fibers of an inorganic material or polymer fibers that are dispersed in or bonded by the polymer, wherein the polymer is a polymerization or crosslinking product of a reactive additive comprising (i) a first liquid solvent that is polymerizable, (ii) an initiator or crosslinking agent, and (iii) the lithium salt and wherein the polymer composite separator has a thickness from 50 nm to 100 μm and a lithium ion conductivity from 10 −8 S/cm to 5×10 −2 S/cm at room temperature;

wherein said inorganic material particles are non-uniformly distributed in the polymer matrix in such a manner that a concentration of the inorganic material particles in one region of the polymer matrix is greater than a concentration of the inorganic material particles in another region.

2 . The polymer composite separator of claim 1 , wherein the first liquid solvent is selected from the group consisting of vinylene carbonate, ethylene carbonate, fluoroethylene carbonate, vinyl sulfite, vinyl ethylene sulfite, vinyl ethylene carbonate, 1,3-propyl sultone, 1,3,5-trioxane (TXE), 1,3-acrylic-sultones, methyl ethylene sulfone, methyl vinyl sulfone, ethyl vinyl sulfone, methyl methacrylate, vinyl acetate, acrylamide, 1,3-dioxolane (DOL), fluorinated ethers, fluorinated esters, sulfides, dinitriles, acrylonitrile (AN), sulfates, siloxanes, silanes, N-methylacetamide, acrylates, ethylene glycols, tetrahydrofuran, combinations thereof, and combinations thereof with phosphates, phosphonates, phosphinates, phosphines, phosphine oxides, phosphonic acids, phosphorous acid, phosphites, phosphoric acids, phosphazene compounds, ionic liquids, derivatives thereof, and mixtures thereof.

3 . The polymer composite separator of claim 1 , wherein said inorganic material comprises particles of an inorganic solid electrolyte material selected from an oxide, sulfide, hydride, halide, borate, phosphate, lithium phosphorus oxynitride (LiPON), Garnet-type, lithium superionic conductor (LISICON) type, sodium superionic conductor (NASICON) type, or a combination thereof.

4 . The polymer composite separator of claim 1 , wherein said inorganic material particles comprise a material selected from a transition metal oxide, aluminum oxide, silicon dioxide, transition metal sulfide, transition metal selenide, alkylated ceramic particles, metal phosphate, metal carbonate, or a combination thereof, or the inorganic material fibers are selected from ceramic fibers, glass fibers, or a combination thereof.

5 . The polymer composite separator of claim 1 , wherein said lithium salt is selected from lithium perchlorate (LiClO 4 ), lithium hexafluorophosphate (LiPF 6 ), lithium borofluoride (LiBF 4 ), lithium hexafluoroarsenide (LiAsF 6 ), lithium trifluoro-methanesulfonate (LiCF 3 SO 3 ), LiN(CF 3 SO 2 ) 2 , lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LiBF 2 C 2 O 4 ), lithium nitrate (LiNO 3 ), Li-fluoroalkyl-phosphates (LiPF 3 (CF 2 CF 3 ) 3 ), lithium bisperfluoro-ethylsulfonylimide (LiBETI), lithium bis(fluorosulfonyl)imide, an ionic liquid-based lithium salt (Li 2 CO 3 , Li 2 O, Li 2 C 2 O 4 , LiOH, LiX, ROCO 2 Li, HCOLi, ROLi, (ROCO 2 Li) 2 , (CH 2 OCO 2 Li) 2 , Li 2 S, Li x SO y , or a combination thereof, wherein X=F, Cl, I, or Br, R=a hydrocarbon group, x=0-1, y=1-4).

6 . The polymer composite separator of claim 1 , further comprising a second liquid solvent that permeates into the separator wherein the second liquid solvent has a higher flash point or lower vapor pressure as compared to the first liquid solvent.

7 . The polymer composite separator of claim 6 , wherein the second liquid solvent is selected from the group consisting of fluoroethylene carbonate, vinyl sulfite, vinyl ethylene sulfite, 1,3-propyl sultone, 1,3,5-trioxane (TXE), 1,3-acrylic-sultones, methyl ethylene sulfone, methyl vinyl sulfone, ethyl vinyl sulfone, methyl methacrylate, vinyl acetate, acrylamide, 1,3-dioxolane (DOL), fluorinated ethers, fluorinated esters, fluorinated vinyl esters, fluorinated vinyl ethers, sulfones, sulfides, dinitriles, acrylonitrile (AN), sulfates, siloxanes, silanes, N-methylacetamide, acrylates, ethylene glycols, tetrahydrofuran, phosphates, phosphonates, phosphinates, phosphines, phosphine oxides, phosphonic acids, phosphorous acid, phosphites, phosphoric acids, phosphazene compounds, ionic liquids, derivatives thereof, and mixtures thereof.

8 . The polymer composite separator of claim 6 , wherein the first or the second liquid solvent comprises a sulfone or sulfide selected from vinyl sulfone, allyl sulfone, alkyl vinyl sulfone, aryl vinyl sulfone, vinyl sulfide, TrMS, MTrMS, TMS, EMS, MMES, EMES, EMEES, or a combination thereof:

9 . The polymer composite separator of claim 8 , 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.

10 . The polymer composite separator of claim 6 , wherein the first or the second liquid solvent comprises a nitrile, a dinitrile selected from AND, GLN, or SEN, or a combination thereof:

11 . The polymer composite separator of claim 6 , wherein the first or the second liquid solvent comprises a phosphate selected from allyl-type, vinyl-type, styrenic-type and (meth)acrylic-type monomers bearing a phosphonate moiety.

12 . The polymer composite separator of claim 6 , wherein the first liquid solvent or the second liquid solvent is selected from the group consisting of 2-alkoxy (or phenoxy)-2-oxo-1,3,2-dioxaphospholane (I) and 2-alkoxy (or phenoxy)-2-oxo-1,3,2-dioxaphosphorinane (II), derivatives thereof, and combinations thereof:

13 . The polymer composite separator of claim 6 , wherein the first liquid solvent or the second liquid solvent comprises phosphate, phosphonate, phosphonic acid, or phosphite 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, and DMMEMP have the following chemical formulae:

wherein an end group thereof or a functional group attached thereof comprises unsaturation for polymerization.

14 . The polymer composite separator of claim 6 , wherein the first liquid solvent or the second liquid solvent comprises phosphonate vinyl monomer selected from the group consisting of phosphonate bearing allyl monomers, phosphonate bearing vinyl monomers, phosphonate bearing styrenic monomers, phosphonate bearing (meth)acrylic monomers, vinylphosphonic acids, and combinations thereof.

15 . The polymer composite separator of claim 14 , wherein the phosphonate bearing allyl monomer is selected from a Dialkyl allylphosphonate monomer or Dioxaphosphorinane allyl monomer; the phosphonate bearing vinyl monomers is selected from a Dialkyl vinyl phosphonate monomer or Dialkyl vinyl ether phosphonate monomer; the phosphonate bearing styrenic monomer is selected from α-, β-, or p-vinylbenzyl phosphonate monomers; or the phosphonate bearing (meth)acrylic monomer is selected from a monomer having a phosphonate group linked to the acrylate double bond, a phosphonate groups linked to the ester, or a phosphonate groups linked to the amide.

16 . The polymer composite separator of claim 1 , wherein the crosslinking agent 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.

17 . The polymer composite separator of claim 1 , wherein the crosslinking agent is selected from poly(diethanol) diacrylate, poly(ethyleneglycol) dimethacrylate, poly(diethanol) dimethylacrylate, poly(ethylene glycol) diacrylate, or a combination thereof.

18 . The polymer composite separator of claim 1 , wherein a concentration of the inorganic material particles in one surface region of the polymer matrix is at least 60% by volume and is greater than a concentration of the inorganic material particles in a core region of the polymer matrix.

19 . The polymer composite separator of claim 1 , wherein the particles or fibers of an inorganic material and/or polymer fibers are in a woven or nonwoven fabric form.

20 . A lithium secondary battery comprising a cathode, an anode, and the flame-resistant polymer composite separator of claim 1 disposed between the cathode and the anode.

21 . The lithium secondary battery of claim 20 , wherein the battery is a lithium metal battery and the anode has an anode current collector but initially the anode has no lithium or lithium alloy as an anode active material supported by said anode current collector when the battery is made and prior to a charge or discharge operation of the battery.

22 . The lithium secondary battery of claim 20 , wherein the battery is a lithium metal battery and the anode has an anode current collector and an amount of lithium or lithium alloy as an anode active material supported by said anode current collector.

23 . The lithium secondary battery of claim 20 , wherein the battery is a lithium-ion battery and the anode has an anode current collector and a layer of an anode active material supported by said anode current collector, wherein the anode active materials is 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 niobium oxide, 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.

24 . The lithium secondary battery of claim 20 , wherein said battery further comprises, in addition to the solid electrolyte in the separator, a working electrolyte in ionic contact with an anode active material and/or a cathode active material wherein said working electrolyte is selected from an organic liquid electrolyte, ionic liquid electrolyte, polymer gel electrolyte, polymer solid electrolyte, solid-state inorganic electrolyte, quasi-solid electrolyte having a lithium salt dissolved in an organic or ionic liquid with a lithium salt concentration higher than 2.0 M, or a combination thereof.

25 . The lithium secondary battery of claim 20 , wherein the polymer is also present in the anode or the cathode and the polymer comprises the lithium salt dispersed therein.

26 . The lithium secondary battery of claim 20 , wherein said cathode comprises a cathode active material selected from an inorganic material, an organic material, a polymeric material, or a combination thereof.

27 . The lithium secondary battery of claim 26 , wherein said inorganic material, as a cathode active material, is selected from a metal oxide, metal phosphate, metal silicide, metal selenide, transition metal sulfide, metal fluoride, metal chloride, or a combination thereof.

28 . The lithium secondary battery of claim 26 , wherein said inorganic cathode active material is selected from a lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium vanadium oxide, lithium-mixed metal oxide, lithium iron phosphate, lithium manganese phosphate, lithium vanadium phosphate, lithium mixed metal phosphate, lithium metal silicide, or a combination thereof.

29 . The lithium secondary battery of claim 26 , wherein said inorganic cathode active material is selected from a lithium transition metal silicate, denoted as Li 2 MSiO 4 or Li 2 Ma x Mb y SiO 4 , wherein M and Ma are selected from Fe, Mn, Co, Ni, V, or VO; Mb is selected from Fe, Mn, Co, Ni, V, Ti, Al, B, Sn, or Bi; and x+y≤1.

30 . The lithium secondary battery of claim 26 , wherein said cathode active material is selected from 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 (LiMn 2 O 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).

31 . The lithium secondary battery of claim 27 , wherein said metal oxide or metal phosphate is selected from 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.