Highly Stable Al Metal Anode Enabled by Surface Chemical Passivation for Long-Life Aqueous Al Metal Batteries

Aqueous aluminum (Al) metal batteries (AMBs) have received much attention due to their high volumetric energy density, low cost, and high safety. However, the practical application of aqueous AMBs is limited by the electrochemical reversibility of the Al anode, which is often deteriorated by corrosion. Herein, we developed a dense passivation layer based on Mn/Ti/Zr compounds on the Al metal anode by a rapid surface passivation strategy. The passivation layer can effectively uniform Al deposition, increase corrosion resistance, and significantly enhance the cycling stability of Al anodes in both symmetric and full cells. Symmetric cells assembled with the treated Al electrodes exhibit stable cycling for over 300 cycles at 0.1 mA cm–2 and 0.05 mA h cm–2, and a 600-cycle life is achieved for a prototype full cell. This work provides a versatile remedy for the limited cycle life of Al metal anodes for rechargeable aqueous batteries.