Sericin-derived carbon wrapped NiS2/V2O3 heterostructure for high-rate capability sodium-ion batteries

Sodium-ion batteries (SIBs) present a prospective solution for energy storage, benefitting from their cost-effectiveness and the abundant availability of sodium reserves on Earth. The effective design of electrode materials with superior cyclability and exceptional rate capability are essential for their widespread application. In this paper, a heterostructure between binary nickel sulfide (NiS2) and vanadium trioxide (V2O3) was initially synthesized by a feasible hydrothermal and subsequent high-temperature calcination technique, which consisted of coin-like V2O3 tiny sheets adhering to the surface of NiS2 microsphere. After coating a layer of sericin-derived carbon (SC) films onto surface of NiS2/V2O3, as-synthesized NiS2/V2O3@SC composite anodes for SIBs exhibited impressive electrochemical Na+ storage performances involving an initial discharge capacity of 671.2 mAh g−1 at 1 A g−1, a capacity decay of only 0.043 and 0.066 % per cycle within 1000 cycles at 1 A g−1 and 8 A g−1, and the rate capability of 32 A g−1 with a capacity output of 406.4 mAh g−1. The NiS2/V2O3 heterostructure with a hierarchical structure will beneficially alleviate agglomeration and volumetric expansion of active materials, improve electrical conductivity, and more importantly, enhance electrochemical kinetic transport of Na+, which makes it a potential anode application for SIBs.