Hydrolysis Precipitation Synthesis of SnO2·XH2O as Electrode Materials for Supercapacitors

Electrode materials of SnO2·XH2O were synthesized by hydrolysis precipitation process. After calcination at various temperatures, the materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). XRD patterns confirm that the structure of SnO2·XH2O is tetragonal (rutile). TEM images reveal the morphology of the SnO2·XH2O. TGA shows the water content in SnO2·XH2O decreases as the calcination temperature increases. Electrochemical tests, such as cyclic voltammetry (CV), chronopotentiometry and cycling were also performed to study the supercapacitor behavior of SnO2·XH2O. CV results indicate that SnO2·XH2O calcined at 200 °C has a specific capacitance of 36.1 F/g at the scan rate of 5 mV/s in 0.5 mol/L H2SO4 electrolyte. Cycling test of the same sample also shows excellent long-term cyclic stability, which has lost less than 2% of the total specific capacitance after 2000 cycles. These results indicate that the prepared SnO2·XH2O materials are excellent candidates as electrode materials for supercapacitors.