SOLID ELECTROLYTE SHEET AND PREPARATION METHOD THEREFOR, BATTERY AND DEVICE CONTAINING SAME

The present application provides a preparation method for a solid electrolyte, including: acquiring an initial reaction mixture comprising a lithium precursor, a central atom ligand and an organic solvent; acquiring a modified solution comprising a borate ester and the organic solvent; mixing the initial reaction mixture and the modified solution, drying to acquire an initial product; performing a grinding, cold press and heat treatment to the initial product to obtain the solid electrolyte. In the preparation method provided by the present application, a B and O co-doped sulphide solid electrolyte can be obtained by modifying the sulphide solid electrolyte with the borate ester as a doping raw material. During the doping and modification process, sufficient mixing between the sulphide electrolyte raw material and the borate ester is achieved; and the borate ester is completely decomposed at the phase formation temperature of the sulphide electrolyte, reducing the introduction of impurities or residual reactants, the ionic conductivity of the prepared sulphide solid electrolyte is significantly improved, which is also conducive to improvement of energy density of the all-solid-state batteries.