Molecular Topological Anchoring Enables Thermodynamic–Kinetic Synergy in Hard-Carbon Anodes

Abstract

The practical deployment of hard carbon anodes in sodium-ion batteries is severely constrained by inferior sodium insertion thermodynamics and sluggish ion diffusion kinetics. We report a molecular topological anchoring strategy that simultaneously optimizes both aspects by cross-linking sucrose and zinc gluconate. The furan ring of sucrose acts as topological anchors, stabilizing Zn2+ in the atomically dispersed form via C–Zn–O bonds, unlike conventional ZnO templating. This chemistry-driven pathway obviates hydrothermal pretreatment, precalcination and acid-washing, retarding graphitization and promoting expanded interlayers, high defect density, abundant closed pores, and redox-active oxygen groups. These features simultaneously enhance capacity through favorable sodium storage sites and accelerate kinetics via expanded interlayers and low-barrier hopping pathways. The optimized anode delivers 375.9 mA h g–1 with 91.2% initial Coulombic efficiency, outstanding rate capability, and 91% capacity retention over 3000 cycles. This work demonstrates molecular topological engineering as an effective strategy to tune both thermodynamics and kinetics of carbon materials.