▎ 摘　　要

NOVELTY - Composite solid electrolyte comprises first solid electrolyte layer and second solid electrolyte layer. The first solid electrolyte layer comprises organic polymer A, lithium salt, and modified nano-inorganic solid electrolyte. The second solid electrolyte layer includes organic polymer B, lithium salt, nanodiamond, graphene, and dispersant. USE - Composite solid electrolyte is used in solid-state batteries (claimed). ADVANTAGE - The composite solid electrolyte effectively inhibits the generation of solid lithium battery lithium dendritic crystal, improves the energy density of the solid lithium battery, cycle life and safety performance. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing composite solid electrolyte, which involves dispersing inorganic solid electrolyte into the ethanol solution, adding silane coupling agent, stirring and heating to react, centrifuging reaction solution at high speed, washing with ethanol for 2-3 times, taking out precipitate and drying in vacuum to obtain modified inorganic solid electrolyte, dissolving organic polymer A and lithium salt in the solvent and stirring to obtain mixed solution, adding solid electrolyte of the modifier to the mixed solution and stirring to prepare the first slurry, coating on the substrate, and forming first solid electrolyte layer after drying, mixing organic polymer B, lithium salt, nanodiamond, graphene, dispersant and solvent, formulating into second slurry, forming second solid electrolyte layer on the first solid electrolyte layer to obtain composite solid electrolyte.