Phase Diagram Determined Lithium Plating/Stripping Behaviors on Lithiophilic Substrates

Many lithiophilic materials have been proposed as substrates to homogenize the lithium plating, but fundamental understandings are still lacking to the drastically different behaviors of lithium on them. Herein we studied the phase transition process of a series of lithiophilic materials and the lithium plating/stripping behaviors on them. A close correlation was found between the binary phase diagrams and the lithium cycling behaviors. The substrate (such as Ag and Mg) that only forms solid solutions with lithium shows high structural stability during repeated alloying and dealloying because the (lithium-removed porous) particles can guide the lithium deposition and support the interphase layer. In contrast, the materials (such as Au, Al, Zn, Si, and Sn) that form lithium intermetallic compounds become lithium-saturated and cannot modulate the lithium plating thereafter, resulting in poor structural stability and cycling behavior. These findings provide important guidance for the rational selection and design of the substrate in the secondary metal batteries.