Advanced fast-charging anode designs for sodium-ion batteries

Sodium-ion batteries (SIBs) are emerging as a promising next-generation fast-charging technology due to their abundant raw resources, low cost, and low desolvation energy advantages that are especially beneficial under low-temperature conditions. However, achieving ultra-fast charging (i.e., charging times under 15 min) remains challenging. The kinetics of Na⁺ ions are primarily hindered by Na⁺ desolvation sluggish, restricted ion transport within the solid electrolyte interphase (SEI), and slow solid-state diffusion in the anode. Moreover, several fundamental challenges, such as significant volume changes during sodiation/desodiation and interfacial chemistry-induced side reactions, are further exacerbated. This review provides a comprehensive analysis of the key factors limiting the fast-charging capability of SIB anodes and outlines targeted optimization strategies, including bulk structure engineering, synergistic electrolyte design, and the controlled formation of favorable SEI layers. Representative case studies are presented to illustrate both the challenges and recent advances. Finally, this review presents future perspectives and potential pathways to guide the rational design of advanced fast-charging anode materials for SIBs.