Synergistic Heterointerface Engineering and Light‐Assisted Enhancement in NiSe/SnSe Anodes for Ultra‐Stable and High‐Rate Sodium‐Ion Batteries

Sodium‐ion batteries (SIBs) face challenges from sluggish kinetics and volume expansion due to the large Na + radius. Herein, we design a carbon‐coated porous NiSe/SnSe@NC Schottky heterojunction via in‐situ synthesis. The epitaxial growth ensures lattice matching, establishing a built‐in electric field from semi‐metallic NiSe to p‐type SnSe that accelerates electron/Na + separation and migration, reducing the diffusion barrier and boosting redox kinetics. The NC‐derived carbon layer enhances structural stability and conductivity. Leveraging the strong photoresponse of SnSe, the Schottky junction generates photovoltage under visible light, providing additional driving force for Na + transport and enabling light‐enhanced capacity. The anode retains 453.7 mAh g −1 after 1800 cycles at 5 A g −1 , and illumination yields up to 10.01% capacity enhancement. This study synergistically combines heterointerface engineering, surface passivation, and the photoelectric effect, offering a pathway for high‐capacity, ultra‐stable SIB anodes with light‐assisted enhancement.