Interface-structure dual modulation of SnSe nanospheres and anthracite-derived porous carbon for synergistically improved sodium storage

SnSe is widely regarded as a highly promising anode for sodium-ion batteries owing to its high theoretical specific capacity, 2D layered structure and narrow-bandgap semiconductor properties. However, it exhibits sluggish reaction kinetics, severe volume expansion, and low initial Coulombic efficiency (ICE). Herein, we prepare SnSe/C composites through a process combining chemical precipitation and high-energy ball-milling, where SnSe nanocrystals are homogeneously anchored on an anthracite-derived porous C skeleton. Porous C retains the orthorhombic structure and sub-microspheres of SnSe, while constructing strong interfacial bonds and a defect-rich sp2 C network with mesoporous channels. This unique architecture provides continuous pathways for electron/ion transport and significantly shortens Na + diffusion routes, confining the SnSe reconstruction reaction to 1.5∼1.8 V and thereby effectively reducing reaction polarization. Meanwhile, the C skeleton also alleviates the volume expansion of SnSe, inhibits the shuttle effect of Na 2 Se x , and promotes the formation of a thin and uniform solid electrolyte interphase film. Consequently, optimized SnSe/C anode achieves an impressive discharge capacity of 530.2 mAh g −1 with an improved ICE of 84.4% at 0.1 A g −1 , a high-rate capability with a capacity retention of 42.2% (from 0.1 to 10 A g −1 ), and rapid sodium storage capability (246.9 mAh g −1 at 10.0 A g −1 ).