Exploring new anode materials is critical for the development of Sodium-ion batteries (SIBs). Herein, a binary-metal selenide NiCo₂Se₄ was synthesized and investigated as a new anode material for SIBs. After compositing with conductive carbon, the NiCo₂Se₄@C composite delivers a reversible capacity of 603.2 mAh g^-1 with a high initial coulombic efficiency of 85.79% at 0.5 A g^-1. At an ultrahigh current density of 2 A g^-1, a reversible capacity of 377.5 mAh g^-1 can still be obtained after 600 cycles. The detailed Na storage mechanism for NiCo₂Se₄ is revealed. After discharge, Na₂Se, Ni and Co nanoparticles are formed and highly dispersed in Na₂Se matrix. After recharge, NiCo₂Se₄ phase can be regenerated with small amount of CoSe₂ and NiSe phases. The multi-phase coexistence after recharge is responsible for the initial capacity loss and the excellent cycle performance in subsequent cycles.

探索新的负极材料对于开发钠离子电池（SIB）至关重要。在此，合成并研究了二元金属硒化物NiCo ₂ Se ₄作为用于SIBs的新型阳极材料。与导电碳复合后，NiCo ₂ Se ₄ @C复合材料的可逆容量为603.2 mAh g ^-1，在0.5 A g ^-1下的初始库仑效率为85.79％。在2 A g ^-1的超高电流密度下，经过600次循环后仍可获得377.5 mAh g ^-1的可逆容量。揭示了NiCo ₂ Se ₄的详细Na储存机理。出院后_形成了2 Se，Ni和Co纳米颗粒，并高度分散在Na ₂ Se基质中。充值后，镍钴₂硒₄相可与COSE的少量再生₂和NISE相。充电后多相共存是初始容量损失和后续循环中出色的循环性能的原因。