SOLID COMPOSITE ELECTROLYTE

The present invention relates to 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 %), preferably from 60.0 to 97.0 wt %, and more preferably from 70.0 to 96.0 wt %, based on the total weight of the solid composite electrolyte. The invention also relates to 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, and iv) at least one polar aprotic solvent, to a solid state battery comprising the solid composite electrolyte and to use of the solid composite electrolyte in an electrolyte or an electrode of a solid state battery for improving ionic conductivity and mechanical properties.