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.