Facile Growth of Hierarchical SnO2@PPy Composites on Carbon Cloth as All-Solid-State Flexible Supercapacitors

Abstract

A novel nanostructure of SnO2@polypyrrole (PPy) is grown on carbon cloth (CC) by a facile solvothermal method and subsequent chemical oxidative polymerization process in this work. Benefiting from the combination of SnO₂ and PPy, the as-obtained SnO2@PPy/CC composites show significant improvement of electrochemical performances compared to single components. Specifically, the SnO₂@PPy/CC electrode achieves a high areal capacitance of 493.8 mF cm^-2 at 1.0 mA cm^-2, and an admirable rate capability. Furthermore, all-solid-state flexible supercapacitors (FSCs) is constructed using SnO₂@PPy/CC electrodes and polyvinyl alcohol-potassium hydroxide gel electrolyte. Remarkably, the SnO₂@PPy/CC//SnO₂@PPy/CC FSCs show a high energy density of 0.46 mWh cm^-3 at a power density of 1.90 mW cm^-3, superior stability (90.5% capacitance retention after 10000 cycles at 1.0 mA cm^-2) and good mechanical flexibility. This work is expected to bring up new ideas for the development of high-performance FSCs.

Keywords: Flexible supercapacitors, SnO2, polypyrrole