Alloy Anodes for Rechargeable Alkali-Metal Batteries: Progress and Challenge

Alkali metal electrodes (including lithium (Li), sodium (Na), and potassium (K)) have been strongly considered as promising candidates for next-generation batteries, beyond lithium ion batteries, because of their high theoretical specific capacities and very low electrochemical potentials. However, all alkali metal anodes are susceptible to dendrite growth, causing safety concerns, low energy efficiency, and short lifespan, which severely hampers their practical applications in working rechargeable batteries. Recently, alloy anodes with two metal components are effective to protect alkali metal anodes. In this Perspective, we analyze the alkali-metal alloy anodes based on their contribution to dendrite suppression, released capacity, and safety enhancement. Recent progress in alloy anodes, including Li/Na-X alloy (X represents the element of non-alkali metal), Li-Na alloy, and Na-K alloy, is reviewed. The perspectives and clear suggestions on the future of alkali-metal alloy anodes are presented. This sheds fresh light on the rational electrode architecture and materials for alkali metal anode and opens a new chapter for next-generation battery systems.