Slope-Dominated N/S Co-Doped Carbon Anode Derived from Pitch for Sodium-ion Batteries

Carbon-based anode materials have received extensive attention due to their exceptional cycling performance and low cost in sodium-ion batteries, but the poor capacity and slow diffusion kinetics of sodium ions remain a challenge for commercial applications. Herein, we report a N, S codoping strategy based on the capacitance-dominated mechanism via one-step pyrolysis method. The increase in disorder and defect concentrations in carbon materials results in a greater abundance of active sites, facilitating the "adsorption" storage of sodium ions on the surface of the carbon matrix. Consequently, this strategy effectively enhances both the sodium storage capacity and the ion diffusion rate of the carbon electrode material. The optimized N,S-codoped pitch carbon (NSPC) demonstrates a high reversible capacity of 254.3 mAh g–1 at 0.03 A g–1 and retains a capacity of 131.1 mAh g–1 at 5 A g–1. Our study offers valuable insights for the development of cost-effective and safe anode materials for sodium-ion batteries.