Progress and challenges in the use of carbon anodes for high-energy and fast-charging sodium-ion batteries

Sodium-ion batteries (SIBs) are widely recognized as most promising candidates for the next generation of low-cost and high-efficiency energy storage systems. Disordered carbons are the most practical anode materials for SIBs, because of their high reversibility of sodium storage and low sodium intercalation potential. However, current disordered carbon anodes face challenges in the incompatibility of their high plateau capacity and high safety operating voltages, as well as sluggish kinetics of sodium storage, leading to trade-offs in energy density, fast-charging performance, and safety characteristics which severely limit their commercialization. This review focuses on the key factors that restrict the development of carbon anodes in SIBs and analyzes the kinetic behavior of each step in the plateau sodium storage process. The progress in building high-energy and fast-charging SIBs is reviewed from two perspectives: the electrode-electrolyte interface and the microstructural control of the disordered carbon. Critical factors influencing the kinetics of sodium storage and the plateau potential are discussed. Finally, prospects for the development of practical carbon anode materials for SIBs are considered.