Electrochemical supercapacitor studies of hierarchical structured Co2+-substituted SnO2 nanoparticles by a hydrothermal method

Hierarchical structured Co-doped SnO2 nanoparticles are prepared by a low temperature hydrothermal process. The structural and surface morphologies of the SnO2 and Sn1-xCoxO2 nanoparticles are studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The Sn1-xCoxO2 nanoparticles form with a tetragonal rutile structure during the hydrothermal process without further calcination. The pseudo-capacitance behavior of the Sn1-xCoxO2 nanoparticles is characterized by cyclic voltammetry (CV) in 1.0 M H2SO4 electrolyte. The specific capacitance (SC) is found to increase with an increase in cobalt content. A maximum SC of 840 F g(-1) is obtained for a Sn0.96Co0.04O2 composite at a 10 mV s(-1) scan rate. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.