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.