Nano SnO2–Al2O3 mixed oxide and SnO2–Al2O3–carbon composite oxides as new and novel electrodes for supercapacitor applications

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 °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.