Regulating Pseudo‐Graphitic Domain and Closed Pores to Facilitate Plateau Sodium Storage Capacity and Kinetics for Hard Carbon

Abstract Hard carbon anode demonstrates exceptional potential in sodium‐ion batteries due to their cost‐effectivenss and superior plateau capacity. However, the proximity of the plateau capacity to the cut‐off voltage of battery operation and the premature cut‐off voltage response caused by polarization at high rates greatly limit the exploitation of plateau capacities, raising big concerns about inferior rate performance of high‐plateau‐capacity hard carbon. In this work, a facile pre‐oxidation strategy is proposed for fabricating lignin‐derived hard carbon. Both high‐plateau capacity and sodiation kinetics are significantly enhanced due to the introduction of expanded pseudo‐graphitic domains and high‐speed closed pores. Impressively, the optimized hard carbon exhibits an increased reversible capacity from 252.1 to 302.0 mAh g −1 , alongside superior rate performance (174.7 mAh g −1 at 5 C) and stable cyclability over 500 cycles. This study paves a low‐cost and effective pathway to modulate the microstructure of biomass‐derived hard carbon materials for facilitating plateau sodium storage kinetics.