Various transition metal sulfides have been considered alternatives for graphite in the anode of lithium-ion batteries. However, poor cycling property caused by polysulfide dissolution and structure devastation hinders their practical applications. In this work, the NiS₂ has been coated by a g-C₃N₄ layer using a facile gas-solid state reaction for a durable-cycling-performance anode for lithium-ion batteries. The composite anode delivered a specific capacity of 972.4 mAh·g⁻¹ after 500 cycles. This improvement was regarded as a result of enhanced charge transfer by the local internal electric field formation and the key role of g-C₃N₄ in polysulfide hosting and solid electrolyte interphase stabilization, clarifying via ultra-violet electron spectroscopy, density functional theory calculations, and ex-situ XPS approach.