Electrochemical capacitor behavior of SO42-/MxOy (M-Fe, Ti, Zr, Sn)

Abstract SO 4 2− /M x O y (M-Zr, Ti, Sn, Fe) system has been investigated as a potential electrode material for supercapacitors. It is precipitated as metal oxide gel by alkaline hydrolysis of metal precursor, and subsequently impregnated with sulfuric acid and calcined. The SO 4 2− /M x O y is characterized by X-ray diffraction, Fourier-transform infrared and an electrochemical analyzer system. The specific capacitance of SO 4 2− /M x O y is higher than the value of M x O y at the same scan rate. SO 4 2- /M x O y displays a good retention for more than 500 cycles in a cycling test. The experimental results and the thorough analyses described in this work not only provide a potential electrode material for supercapacitors but also give us a new application of the solid super acid.