Porous Al with high surface free energy enables regulated charge transfer via electrochemical etching for high energy density lithium-ion battery

Abstract

Desirable electron transfer via current collectors between as-supported active materials and external circuit is imperative to realize targeted electrochemistry. Enabling surface-mediated pathway of charge carriers in a controllable and efficient manner needs to be carefully addressed but remains a great challenge. Here, we present a cost-efficient strategy for surface modification on Al foils by employing mild electrochemical etching. Well-defined porous nanostructure can be established on commercial Al foils towards promoted surface free energy, which can be also applied on bulk Al-based alloys. Owing to the tailored porosity and increased roughness, desired wetting properties and more importantly, regulated distribution of current density have been realised, according to both experimental observations and simulation results. As expected, LiFePO4 cathodes loaded on porous Al foils demonstrate improved energy density and cycling stability for lithium-ion batteries (LIBs).