Anode-Free Aluminum Electrode with Ultralong Cycle Life and High Coulombic Efficiency Exceeding 99.92% Enabled by a Lattice-Matching Layer

Abstract

Metallic aluminum is an attractive anode owing to its high specific capacity, earth abundance, and low cost. However, the poor reversibility of Al deposition/dissolution and Al dendrites have impeded its deployment. Herein, a strategy for constructing a lattice-matching layer (LML) to regulate the behavior of Al deposition/dissolution is demonstrated. Various experiments and theoretical calculations validate that gold LML as an example can significantly enhance the nucleation density and reduce average particle size, which achieve highly reversible, dendrite-free, durable, and anode-free Al anodes. The metallic Al shows stable Al deposition/dissolution on Au@Ti substrate for more than 4500 h with an average Coulombic efficiency of 99.92%, which is a record-high reported value. Furthermore, the anode-free full cell based on Au@Ti anode and expanded graphite cathode exhibits outstanding long-term stability for 900 cycles with the capacity retention rate of 80%. This study provides an effective strategy to enhance the reversibility and utilization of the Al anode, which provides inspiration for advanced Al batteries.