Abstract: Composite membranes consisting of sulfated zirconia（SZ）and perfluorosulfonic acid-PTFE copolymer（Nafion?）were prepared by solution recasting. The microstructure, morphology, and properties of as-synthesized composite membrane were studiedd by XRD, SEM, and TGA. It showed that rod-like SZ particles were evenly distributed in Nafion? membrane matrix, and slightly modified the thermal stability at medium temperature range. Under the conditions of 45 ℃ and 5 mol/L methanol, the peak power densities of direct methanol fuel cell（DMFC）with 3 % and 6 % Nafion?/SZ composite membranes were 46.27 mW/cm2 and 59.47 mW/cm2, respectively, higher than that of DMFC with pristine Nafion? menbrane.

Key words: perfluorosulfonic acid-polytetrafluoroethene copolymer, sulfated zirconia, solution recasting, composite membrane, direct methanol fuel cell