Performance of Carbon-Nickel Composite Coatings on Laser Surface Roughened Aluminum Foils for Supercapacitor Current Collectors

Surface-engineered aluminum current collectors were developed through laser-based surface modification methods. Their performances as current collectors in supercapacitors clearly outperformed state-of-the-art carbon-coated commercial foils and were close to ideal gold foils, thanks to the enhanced interfaces provided by their engineered surfaces. Surface modifications included roughening by laser ablation in high vacuum, and coating with a carbon-nickel (C 0.97 Ni 0.03 ) composite thin film deposited using pulsed laser deposition. The main improvement was obtained after coating the aluminum foil with the carbon-nickel protective layer, which was attributed to the almost pure sp 2 bonding state of the carbon and a mostly metallic nickel phase. The surface roughening treatment further decreased the interface resistance by providing a higher contact surface and a better mechanical anchorage of the active materials layer. The combination of laser roughening in vacuum conditions and subsequent deposition of an electronically conductive protective coating was therefore demonstrated as an efficient approach to improve the performance of current collectors for supercapacitors.