Lithium-rich alloy as stable lithium metal composite anode for lithium batteries

Lithium (Li) metal is a promising anode material for high energy density Li batteries due to its high specific capacity and low redox potential. However, its practical applications are hindered by issues such as Li dendrites, side reactions, and volumetric changes. Li-rich alloys have demonstrated potential in addressing these issues, as they can be easily synthesized and form an in situ 3D scaffold embedded with metallic Li. This review comprehensively summarizes the properties of representative Li-rich alloys, including binary and multi-element alloys. These alloys consist of both metallic and non-metallic elements, some of which can form solid solutions with Li, while others can form intermetallic compounds. The advantages and disadvantages of these alloys are compared and analyzed. Solid solution alloys are more stable than intermetallic compounds because there is no phase transformation within a certain range during the process of lithiation and delithiation. Li-rich alloys, such as Li-Mg, Li-Sn, and Li-Zn, exhibit promising merits, including high specific capacity, stable scaffold, high ionic conductivity, and low cost. This investigation provides a comprehensive perspective for the development of Li-rich alloy anodes towards practical application.