Hyperbranched poly(glycidol) alkali sulfate (SHPG-M) was prepared based on hyperbranched poly(glycidol). Polyurethane-hyperbranched poly(glycidol) (PUSHPG-M) sulfate electrolyte is a kind of single ionic or cationic conducting polymer electrolyte. Such a single ionic polymer electrolyte can obviously reduce the polarization and has little decay of direct current (DC) conductivity. SHPG-M was characterized by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), atomic force microscopy (AFM) and impedance analysis. The optimum conductivity is similar to3 X 10(-6) S(.)cm(-1), with 30-40% SHPG-M in the polymer electrolyte at room temperature. The species of cation greatly effects the ionic conductivity of the polymer electrolyte; that is, sigma(SHPG-Li) > sigma(SHPG-Na) > sigma(SHPG-K), with same SHPG-M content in the polymer electrolyte. The ionic conductivity increases with an increase of temperature, and the dependence of ionic conductivity on temperature fits the Arrhenius equation well. (C) 2003 Wiley Periodicals, Inc.