Constructing Ultrafine Tin Dioxide/Few-Walled Carbon Nanotube Composites for High-performance Supercapacitors

A hydrothermal/calcination method was successfully applied to prepare ultrafine tin dioxide (SnO2)/few-walled carbon nanotube (FWNT) composites (SnO2@FWNT). The corresponding morphological and structural information were further obtained by the characterization technique of transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. In the SnO2@FWNT composites, ultrafine SnO2 nanoparticles with an average size of 2-3 nm were uniformly distributed on the FWNT with a thickness of 2-5 layers. With the synergistic effect of highly conductive FWNT and highly dispersed SnO2, the SnO2@FWNT hybrids presented excellent specific capacitance of 220.5 F g -1 at a scan rate of 2 mV s -1 under neutral environment. A power density of 30.63 kW kg -1 and an energy density of 512.79 W kg -1 were obtained, respectively. In addition, a specific capacity retention rate of 89.57% was acquired after 1000 cycles, indicating a superior stability of SnO2@FWNT hybrids. The results indicate that the SnO2@FWNT composites can be used as an alternative electrode material for high-performance supercapacitors.