Pore Structure Engineering Enables Synergistic Interfacial–Bulk Kinetics in Hard Carbon for High-Rate Sodium-Ion Batteries

Although hard carbon is considered a viable anode for sodium-ion batteries (SIBs) due to its economic advantages and readily available precursors, its commercialization is constrained by inherently low initial Coulombic efficiency (ICE) and rapid capacity decay under extreme operating conditions. Herein, we synthesized a multiscale porous ZHC anode featuring simultaneous interfacial and bulk regulation by exploiting the physical and chemical modulation effects of organic compounds. The micropore/mesopore size, and specific interface area were increased, while the bulk structure became more disordered, accompanied by an expansion of the closed-pore radius to 0.82 nm. This synergistic interfacial–bulk regulation enables the ZHC anode to deliver high ICE values of 88.32%, 82.76%, and 93.26% at 25 °C, −10 °C, and 50 °C, respectively. At 0.5 A g –1 and 50 °C, the ZHC electrode exhibits 244.52 mAh g –1 with 77.17% capacity retention after 300 cycles. The ZHC||NVP cell delivers 251.47 mAh g –1 (0.05 A g –1 ). This work demonstrates that an appropriate pore structure can enhance interfacial–bulk kinetics, thereby providing experimental guidance for promoting high-power SIBs.