Mg-Rich LAPONITE® interface protective layer enables reversible, corrosion-resistant anodes for high-performance magnesium metal batteries†

Magnesium metal batteries (MMBs) are considered one of the most promising candidates for the post-lithium era but face significant challenges, including non-uniform plating, irregular stripping, and interface passivation. Herein, we have developed a highly reversible, passivation-free, and corrosion-resistant Mg metal anode by integrating a Mg-rich LAPONITE® (Mg-RL) interface protective layer using a doctor-blading technique. The Mg-RL interface protective layer, with its negatively charged interlayer structure, creates abundant cation transport channels and isolates direct contact between the electrolyte and anode, thus facilitating highly reversible Mg plating/stripping while suppressing anode passivation. As a result, Mg-RL/Mg-based symmetric cells exhibit exceptional cycling stability, maintaining over 1500 h in APC electrolyte and 800 h in Mg(TFSI)₂ electrolyte under practical current densities and area capacities. Furthermore, the corresponding Mo₆S₈-based full cells demonstrate excellent electrochemical performance, and the Mg–S pouch cells successfully power a toy car, demonstrating practical viability. This study presents a simple, cost-effective strategy for constructing artificial interface protective layers of Mg metal anodes, advancing the development of stable and safe MMBs.