The pathway toward practical application of lithium-metal anodes for non-aqueous secondary batteries.

The revolution of automotive vehicles (from petrol vehicles to electric vehicles) has set high demands for the performance of batteries. Lithium-metal batteries (LMBs) show great potential owing to their high energy density but encounter poor cycle life and safety issues. It is of great significance to reveal LMB failure mechanisms and understand their relationship with battery performance. This review presents an overview of the state-of-the-art Li-metal anodes, with an emphasis on two typical failure modes: capacity degradation and dendritic growth of Li metal. The critical correlations between the composition, structure and failure are explained point by point. The chemical and electrochemical stabilities of the lithium anode are discussed. Particularly, for the first time, five types of lithium-metal anodes are classified to develop a comprehensive understanding of LMBs. Furthermore, strategies are suggested to improve the practical performance of LMBs, including material innovation, electrolyte modification and advanced characterization.