Spatial Structural Self‐Regulation Engineering Increases Close Pores of Starch‐Derived Hard Carbon for Sodium‐Ion Batteries

Starch, a sustainable precursor for hard carbon (HC) in sodium‐ion batteries (SIBs), faces challenges of low carbon yield (~10%), foaming, and excessive graphitization during carbonization. Herein, a unique spatial structural self‐regulation strategy is proposed to precisely program the microstructure of starch‐derived HC with the pre‐oxidation method, transforming its helical chains into a robust, three‐dimensional cross‐linked framework. This strategy regulates microstructure evolution by inducing self‐carbonylation of hydroxyl groups, suppressing foaming and graphitization, and controlling pore evolution at the molecular level to form closed‐pore‐encoded carbon microdomains. The resulting material achieves a carbon yield of 26%, a 2.6‐fold improvement, and a high‐density closed‐pore structure. Resultantly, CS‐O‐1400 delivers 385 mAh g −1 reversible capacity, 92.36% initial Coulombic efficiency (ICE), and 278 mAh g − 1 rate capability at 2 A g − 1 . Furthermore, in situ Raman and electron paramagnetic resonance (EPR) technologies jointly reveal that HC with short‐range graphitic crystallites triggers intercalation‐dominated sodium storage while synergistically coordinating adsorption and pore‐filling mechanisms, forming a marked contrast to the stepwise reaction sequence observed in long‐range graphitic crystallite configurations. This work demonstrates that spatial structural self‐regulation engineering is a simple and efficient approach to optimizing the electrochemical performance of HC for SIBs.