SOLID COMPOSITE ELECTROLYTE

1 . A solid composite electrolyte comprising:

i) at least one polymer;

ii) at least one sulfide-based solid ionic conducting inorganic particle; and

iii) at least one lithium salt,

wherein the i) at least one polymer is selected from the group consisting of (co)polymers having recurring units derived from vinylidene fluoride (VDF), alkylene carbonate, acrylonitrile, silane, fluorosilane, acrylate, caprolactone and blends thereof, and wherein an amount of the ii) at least one sulfide-based solid ionic conducting inorganic particle is from 40.0 to 98.0% by weight (wt %), based on the total weight of the solid composite electrolyte.

2 . The solid composite electrolyte according to claim 1 , wherein the ii) at least one sulfide-based solid ionic conducting inorganic particle comprises glass, crystalline or glass-ceramic of those of formula (Li 2 S) x —(P 2 S 5 ) y , wherein x+y=1 and 0≤x≤1, Li 7 P 3 S 11 , Li 7 PS 6 , Li 4 P 2 S 6 , Li 9.6 P 3 S 12 and Li 3 PS 4 ; Li 2 CuPS 4 , Li 1+2x Zn 1−x PS 4 , wherein 0≤x≤1, Li 3.33 Mg 0.33 P 2 S 6 , and Li 4−3x Sc x P 2 S 6 , wherein 0≤x≤1; Li x P y S z O, wherein 0.33≤x≤0.67, 0.07≤y≤0.2, 0.4≤z≤0.55; Li 10 SnP 2 S 12 , Li 10 GeP 2 S 12 , Li 10 SiP 2 S 12 , and Li 2 S—P 2 S 5 —SnS; lithium phosphorus sulfide oxygen including X (“LXPSO”), wherein X is Si, Ge, Sn, As, or Al; Li 2 SiS 3 , Li 2 S—P 2 S 5 —SiS 2 , Li 2 S—P 2 S 5 —SiS 2 —LiCl, Li 2 S—SiS 2 —P 2 S 5 , Li 2 S—SiS 2 —P 2 S 5 —LiI, Li 2 S—SiS 2 —LiI, Li 2 S—SiS 2 , Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 , and Li 2 S—SiS 2 —Al 2 S 3 ; Li 3 BS 3 and Li 2 S—B 2 S 3 —LiI; Li 0.8 Sn 0.8 S 2 , Li 4 SnS 4 , Li 3.833 Sn 0.833 As 0.166 S 4 , Li 3 AsS 4 —Li 4 SnS 4 , and Ge-substituted Li 3 AsS 4 ; Li 4 PS 4 Cl, Li 15 P 3 S 16 Cl 3 , Li 7 P 2 S 8 Cl, and Li 7 P 2 S 8 I; Argyrodite-type Li 6 PS 5 Y (Y═Cl, Br, or I); Li 2 S—GeS 2 —ZnS, Li 3 SbS 4 , Na 3 PS 4 , Na 10 SnP 12 S 12 , and Na 11 Sn 2 PS 12 ; and blends thereof.

3 . The solid composite electrolyte according to claim 2 , wherein the ii) at least one sulfide-based solid ionic conducting inorganic particle comprises Argyrodite-type Li 6 PS 5 Y (Y=Cl, Br, or I) and Li 10 SnP 2 S 12 .

4 . The solid composite electrolyte according to claim 1 , wherein the i) at least one polymer comprises

(a) at least 85% by moles of recurring units derived from VDF; and

(b) optionally from 0.1 to 15%, by moles of recurring units derived from vinyl fluoride, chlorotrifluoroethylene (CTFE), hexafluoropropene (HFP), tetrafluoroethylene (TFE), perfluoromethylvinylether (PMVE), trifluoroethylene (TrFE) or mixtures thereof,

wherein all the aforementioned % by moles is referred to the total moles of recurring units of the polymer.

5 . The solid composite electrolyte according to claim 1 , wherein

(a) less than 85% by moles of recurring units derived from VDF;

(b) at least 15% by moles of recurring units derived from vinyl fluoride, chlorotrifluoroethylene (CTFE), hexafluoropropene (HFP), tetrafluoroethylene (TFE), perfluoromethylvinylether (PMVE), trifluoroethylene (TrFE) or mixtures thereof,

wherein all the aforementioned % by moles is referred to the total moles of recurring units of the polymer

6 . The solid composite electrolyte according to claim 1 , wherein the i) at least one polymer comprises recurring units derived from ethylene carbonate, propylene carbonate, butylene carbonate, trimethylene carbonate, cyclohexene carbonate, bisphenol A, B and F carbonate, or mixtures thereof.

7 . The solid composite electrolyte according to claim 1 , wherein the i) at least one polymer comprises recurring units derived from acrylonitrile and recurring units derived from styrene, butadiene, acrylate, methyl acrylate, vinyl acetate or mixtures thereof.

8 . The solid composite electrolyte according to claim 1 , wherein the i) at least one polymer comprises recurring units derived from dimethyl dichlorosilane, methyltrimethoxy silane, methyl trichlorosilane or mixtures thereof.

9 . The solid composite electrolyte according to claim 1 , wherein the i) at least one polymer comprises recurring units derived from acrylate, methacrylate, cyanoacrylate, caprolactone or mixtures thereof.

10 . The solid composite electrolyte according to claim 1 , wherein iii) at least one lithium salt comprises at least one selected from the group consisting of lithium hexafluorophosphate (LiPF 6 ), lithium bis(fluorosulfonyl)imide Li(FSO 2 ) 2 N (LiFSI), lithium 2-trifluoromethyl-4,5-dicyanoimidazole (LiTDI), LiBF 4 , LiB(C 2 O 4 ) 2 , LiAsF 6 , LiClO 4 , LiNO 3 , lithium bis(oxalato)borate, LiCF 3 SO 3 , LiN(SO 2 CF 3 ) 2 (LiTFSI), LiN(SO 2 C 2 F 5 ) 2 , LiC(SO 2 CF 3 ) 3 , LiN(SO 3 CF 3 ) 2 , LiC 4 F 9 SO 3 , LiCF 93 SO 3 , LiAlCl 4 , LiSbF 6 , LiF, LiBr, LiCl, LiOH, LiPFSi, and lithium trifluoromethanesulfonate.

11 . The solid composite electrolyte according to claim 1 , wherein the wt % of the ii) at least one Li salt in the i) at least one polymer varies in between 10 and 80 wt %.

12 . A slurry for manufacturing a solid composite electrolyte comprising:

i. at least one polymer,

ii. at least one sulfide-based solid ionic conducting inorganic particle,

iii. at least one lithium salt according to claim 1 , and

iv. at least one polar aprotic solvent.

13 . The slurry according to claim 12 , wherein the iv) polar aprotic solvent comprises nitrile-containing solvents, ethers and esters.

14 . A solid state battery comprising the solid composite electrolyte according to claim 1 .

15 . An electrolyte or an electrode of a solid state battery comprising the solid composite electrolyte according to claim 1 for improved ionic conductivity and mechanical properties.