NiSe/ZnSe heterojunctions derived from truncated rhombic dodecahedra for stable and high-power sodium-ion batteries

Transition metal selenides (TMSe) considered as a promising anode material have attracted great attention for sodium-ion batteries (SIBs). However, their practical application suffers from low intrinsic conductivity, sluggish reaction kinetics and pronounced volume expansion. Here, a spherical NiSe/ZnSe heterojunction composite is designed through selenization of a precursor with a unique truncated rhombic dodecahedral configuration. Such selenide-derived spherical particles and heterojunction structure can effectively enhance electron transfer and Na+ diffusion by optimizing charge transport pathways, and buffer volume strain during charging and discharging cycles. Accordingly, the NiSe/ZnSe-based electrode exhibits remarkable rate performance (358.4 mAh g−1 at 50 A g−1), outstanding long-term cycling stability at high currents (396.6 mAh g−1 capacity retention after 1500 cycles at 40 A g−1), and practical full-cell performance (164.2 mAh g−1 capacity retention after 400 cycles at 1 A g−1). Our study inspires the rational design of TMSe-based SIB anodes via a triple-regulation strategy of morphology, composition and interface.