Silica-templated ordered mesoporous carbon thin films as electrodes for micro-capacitors

Abstract

A binderless continuous thin film of a mesoporous carbon material was directly synthesized on a graphite current collector using an ordered mesoporous silica thin film as a hard-template. The nanostructure of the silica, the composite silica/carbon and the mesoporous carbon thin films was characterized by field emission scanning electron microscopy coupled to energy dispersive X-ray spectroscopy, transmission electron microscopy and Raman spectroscopy. The silica thin film, which was uniformly deposited onto the graphite plate surface, presented mesopores of around 8 nm perpendicularly disposed to the current collector. The carbon thin film, which almost replicates the nanostructure of the silica thin film, showed mesopores of around 2–3 nm. Electrochemical characterization of both the mesoporous carbon and the composite silica/carbon thin films, by cyclic voltammetry and galvanostatic charge–discharge in a 1 M H₂SO₄ solution, demonstrated that the synthesized thin films showed exceptional properties in terms of specific capacitance, rate performance and electrochemical stability to be used as electrodes for micro-capacitors.