Boosting Fast Sodium Storage of a Large-Scalable Carbon Anode with an Ultralong Cycle Life

Sodium-ion batteries (SIBs) are considered to be a promising alternative for large-scale electricity storage. However, it is urgent to develop new anode materials with superior ultralong cycle life performance at high current rates. Herein, a low-cost and large-scalable sulfur-doped carbon anode material that exhibits the best high-rate cycle performance and the longest cycle life ever reported for carbon anodes is developed. The material delivers a reversible capacity of 142 mA h g⁻¹ at a current rate up to 10 A g⁻¹. After 10 000 cycles the capacity is remained at 126.5 mA h g⁻¹; 89.1% of the initial value. Density functional theory computations demonstrate that the sulfur-doped carbon has a strong binding affinity for sodium which promotes sodium storage. Meanwhile, the kinetics analysis identifies the capacitive charge storage as a large contributor to sodium storage, which favors ultrafast storage of sodium ions. These results demonstrate a new way to design carbon-based SIBs anodes for next-generation large-scale electricity storage.