Laser Surface Roughening of Aluminum Foils for Supercapacitor Current Collectors

Abstract

Thin aluminum foils were surface roughened by laser ablation in high vacuum conditions. Their performance as current collectors for carbon-based supercapacitors were evaluated by impedance spectroscopy, cyclic voltammetry and galvanostatic cycling, and compared with those of gold plates, flat aluminum foils and commercially available carbon-coated aluminum foils (Z-flo). The results revealed that the laser surface treatment significantly enhances the electronic contact between the current collector and the active materials layers. The benefits in interface enhancement are comparable to those of a carbon coating. High power performances were reached thanks to a significantly decreased internal resistance. Long-term cycling performance revealed a slight but continuous capacity fading for supercapacitor cells having laser-treated current collectors, which was caused by the progressive growth of a surface aluminum oxide layer on the current collector. Cells assembled with carbon-coated collectors did not display the same fading thanks to the protection provided by the interfacial carbon layer. This work demonstrates that laser ablation in vacuum is a promising technique for the preparation supercapacitor current collectors with surface oxide-free and controllable surface microstructures toward specific active materials.