Improving the Specific Surface Area of Etched Aluminum Foil by Fabricating the Micro/Nano Structure

Abstract

Aluminum foil with micro/nano structure has been prepared by electrochemical DC etching and a subsequent anodization treatment followed by removal of the alumina film. When the micron-sized tunnels were generated on the etched aluminum foil, the size and distribution of the nano-concave formed on the sidewall of the etched tunnels varied with the anodized time in H2SO4 and C4H6O6 electrolyte. The optimal value of the specific surface area for the aluminum foil with micro/nano structure is approximately four times larger than that of the only etched aluminum foil. It is indicated from the chronoamperometry and BET measurements that the specific capacitance of aluminum foil with micro/nano structure can be significantly improved by suitable anodization in H2SO4 electrolyte, in comparison with a comparatively small increasement in C4H6O6 electrolyte. This can be attributed to the fact that the tardy anodization process will consume a considerable amount of aluminum substrate, resulting in the aggravation of the merged tunnels.