Interfacial Electronic Coupling in the GeSe 2 /Volcanic‐Rock–Like Carbon Framework Activates Reversible Intermediate Conversion for High‐Rate Sodium Storage

ABSTRACT GeSe 2 is a promising conversion–alloying anode for sodium‐ion batteries owing to its high theoretical capacity, suitable operating voltage, and layered structure. However, its practical application is hindered by severe volume expansion, sluggish Na + transport kinetics, unstable interfacial evolution, and irreversible sodiation intermediates. Herein, GeSe 2 nanosheets are uniformly anchored on a coal‐gasification‐residue–derived volcanic‐rock–like carbon framework through a combined sol‐gel and solid‐state selenization strategy, constructing a robust GeSe 2 /C composite. The carbon framework buffers the volume variation of GeSe 2 , stabilizes the solid–electrolyte interphase, and provides continuous pathways for rapid electron/ion transport. Significantly, Se─C‐bond–mediated interfacial electronic coupling induces charge redistribution at the GeSe 2 /C interface, enhancing Na + adsorption and migration in GeSe 2 and its key intermediates, Na 2 Ge 2 Se 5 and Na 2 GeSe 3 . This promotes the electrochemical reversibility of sodiation intermediates, suppresses irreversible Na + consumption, and improves the initial Coulombic efficiency. Consequently, the optimized GeSe 2 /C anode delivers 389.6 mAh g −1 at 0.1 A g −1 and retains 308.9 mAh g −1 at 20.0 A g −1 , corresponding to 79.3% capacity retention. The initial Coulombic efficiency (ICE) increases from 47.4% for pristine GeSe 2 to 74.0% for GeSe 2 /C, with the normalized ICE of GeSe 2 reaching 81.8%. Moreover, GeSe 2 /C maintains 297.2 mAh g −1 after 2000 cycles at 20.0 A g −1 , demonstrating excellent high‐rate sodium‐storage durability.