New nano-materials like SnO2-Al2O3 and SnO2-Al2O3-carbon were synthesized by a single step hydrothermal method in searching for novel mixed oxides with high electrochemical double layer capacitance. A SnO2-Al2O3-carbon sample was calcined at 600 degrees C and tested for its performance. The source of carbon was tetrapropyl ammonium hydroxide. The capacitive behavior of SnO2 was compared to the performance of SnO2-Al2O3, SnO2-Al2O3-carbon and calcined SnO2-Al2O3-carbon using the techniques of cyclic voltammetry, double potential step, chronopotentiometry and E-log I polarization. In 0.1 M NaCl solutions, SnO2-Al2O3 gave the best performance with a value of 119 Fg(-1) and cycled 1000 times. The nano-material mixed oxides were characterized by TEM, XRD, ICP-AES and SEM-EDAX. (c) 2005 Elsevier B.V. All rights reserved.