Alloy anodes for sodium-ion batteries

Sodium-ion batteries (SIBs) have emerged as one of the most promising candidates for next-generation energy storage systems because sodium is abundant in nature. The practical application of SIBs critically depends on developing robust electrode materials with high specific capacity and long cycling life, developing suitable anode materials is even more challenging. Alloy-type anodes are attractive for their high gravimetric and volumetric specific capacities, demonstrating great potential for high-energy SIBs, however, huge volume swelling hampered their practical application. Given the encouraging breakthroughs on alloy anodes for SIBs, herein, we present a review of the up-to-date progress and works carried out with alloy-based anode materials for SIBs. We review the synthetic strategies and their detailed electrochemical performance. In particular, we extensively reveal the important roles of alloy-based anodes in the development of SIBs. Research progress of alloy-type anodes and their compounds for sodium storage is summarized. Specific efforts to enhance the electrochemical performance of the alloy-based anode materials are discussed. Finally, we proposed multi-component alloys/high-entropy alloys (HEAs) as further research directions for alloy-based anodes.