Hollow Tin Dioxide Microspheres With Multilayered Nanocrystalline Shells for Pseudocapacitor

Nanocrystalline SnO2 is successfully assembled into highly-ordered hollow microspheres by a facile procedure consisting of hydrothermal synthesis and assistance of templates, then high temperature calcination. The structures consist of highly crystalline grains with hexagonal shape and about 11 nm mean size. Kirkendall effect directs the diffusion of SnO2 nanocrystals and carbon dioxide and causes the formation of hollow SnO2 spheres. Effect of the concentration of Sn precursor and acid value on the SnO2 morphology and SnO2 electrochemistry properties for pseudocapacitor are employed. Electrochemical measurements demonstrate that the maximum specific capacitance of hollow SnO2 microspheres is 178.86 F g(-1) at a scan rate of 1mVs(-1) in 1M KOH solution and originated from Faradaic redox reactions. Also the specific capacitance only decays 4.8% from 150 cycles to 200 cycles and keeps constant from 200-2000 cycles. The present results clearly indicate that hollow SnO2 spheres with layered crystalline structures are very attractive materials for energy storage because of their ability to intercalate ions into a wide range of sites. (C) 2015 Elsevier Ltd. All rights reserved.