▎ 摘　　要

NOVELTY - A composite material comprises microsized bismuth telluride (Bi2Te3) and graphene sheet. USE - Composite material used as thermoelectric material (claimed). ADVANTAGE - The composite material has dispersed and isolated action of graphite which can effectively prevent sintering of Bi2Te3 sheet in the heat treatment process to keep the grain boundary to phonon scattering to improve the thermoelectric performance of the Bi2Te3 material. The preparation method of the composite material involves one-step hydrothermal method or one-step solvent thermal method which has simple technique, low cost, short period, and low energy consumption. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the composite material, comprising: (A) adding elemental tellurium or tellurium-containing compound and a compound containing bismuth according to stoichiometric ratio of Bi2Te3 in deionized water or organic solvent to obtain 0.015-0.15 mol/L Bi2Te3 solution; (B) adding graphene oxide into the Bi2Te3 solution and dispersing, then adding reducing agent and alkali regulator to regulate pH value of the mixed solution to 8-12, then sealing and reacting at 100-250 degrees C for 12-72 hours; and (C) cooling, collecting the solid product, repeatedly washing, drying to obtain Bi2Te3 sheet/graphene composite material, washing with deionized water and absolute ethyl alcohol.