Network structure of SnO2 hollow sphere/PANI nanocomposites for electrochemical performance.

Homogeneous SnO2 hollow spheres have been synthesized through a hydrothermal method without a template, followed by in situ polymerization of PANI. The resulting SnO2 hollow spheres were uniformly deposited onto the surface or embedded into the PANI nanofibers to form a SnO2-PANI network structure. As electrode materials, the SnO2-PANI composites exhibit greatly enhanced specific capacitance (477 F g-1 at a current density of 1 A g-1) and superior cycling performance (no capacitance loss after 3000 galvanostatic charge-discharge cycles). These intriguing features are attributed to the interaction between the SnO2 hollow spheres and PANI network. On the one hand, the SnO2 spheres not only provide larger area for electrochemical reaction but also release volume expansion during the charge-discharge process. On the other hand, the conducting PANI improves electrical conductivity and maintains mechanical integrity of the composites as well.