Synthesis and regulation strategies for enhancing the electrochemical performance of sodium-ion battery anode materials

Rechargeable sodium-ion batteries (SIBs) have attracted increasing research interest because of their inherent advantages such as a similar working principle to lithium-ion batteries (LIBs) and plentiful, even-distributed, and inexpensive Na resources. However, Na ions possess a larger ionic radius (1.07 Å) compared to that of Li ions (0.76 Å), which brings key challenges such as irreversible capacity loss, sluggish kinetics, a considerable volume expansion, and low initial coulombic efficiency (ICE) of SIBs, especially for anodes. Despite these challenges, there have been ongoing efforts to develop various synthesis and regulation strategies to enhance the electrochemical performance of SIB anode materials and they are summarized here. In this review, the significance of developing SIBs, the types of SIB anode materials, and the key issues SIB anode materials face are discussed first. Then various developed synthesis and regulation strategies such as compositional, structural, and interfacial regulations based on different synthesis methods to enhance the electrochemical performance of SIB anode materials are summarized. Finally, in conclusions and outlooks, the present status of SIB anode materials is concluded and the future development directions are proposed.