In Situ CVD Synthesis of Wrinkled Scale-Like Carbon Arrays on ZnO Template and Their Use to Supercapacitors

Abstract

A ZnO/C core/shell structure has been synthesized using in situ CVD. A ZnO nanowire array on a Ti substrate was used as both the template and catalyst. The carbon shells form a unique wrinkled scaly structure in the presence of H2, while only a shell of rough carbon was deposited on the ZnO surface in the absence of H2. After removing the ZnO core, the scaly carbon array remains on the Ti substrate and has an extremely high specific surface area (∼990 m2 g–1) and electrical conductivity (∼103 S m–1), which are two vital factors for the use of this material in supercapacitors. Electrochemical tests show a high specific capacitance (140 F g–1) and excellent cycling performance of ∼81% capacitance retention over 10 000 cycles in a 1 M H2SO4 electrolyte. Experiments using the rough carbon shells coated intimately on the ZnO exhibited a much lower specific capacitance.