A solid–solution-based Li–Mg alloy for highly stable lithium metal anodes

Abstract

The uncontrollable growth of Li dendrites is the main challenge for the practical application of Li-metal anodes in high-energy rechargeable Li batteries. Herein, a facile method is reported to stabilize Li-metal anodes via constructing a solid–solution-based Li–Mg alloy with the mechanical rolling method. During battery cycling, the Li–Mg alloy framework serves as an electron/ion dual-conductive Li host, inhibiting lithium dendrites and volume change. Moreover, the effects of Li–Mg alloys with different Mg contents on the stability of the lithium metal anode are also investigated. Lithiophilic Li–Mg solid–solution alloys not only guide uniform Li deposition, but also promote Li extraction during the stripping process, suppressing the parasitic reaction and Li dendrites on the surface of the Li metal anode. As a result, the Li–Mg alloy anode exhibits stable and dendrite-free cycling performance with a capacity of 0.45 mA h cm⁻² over 6000 h. When coupling this anode with LiCoO₂ cathodes, the full cell delivers excellent cycling stability. This work provides a novel strategy to optimize metal anodes for next generation high-energy Li metal batteries.