Construction of γ-MnS/α-MnS hetero-phase junction for high-performance sodium-ion batteries

As electrode material for sodium-ion batteries (SIBs), MnS shows high theory capacity and low cost, but suffers from inferior cyclicity and rate capability. Inspired by the polymouphous characteristic of MnS, a unique and effective hetero-phase junction (HPJ) strategy is proposed for Na-ion storage. With simple high-temperature-induced phase transformation, hollow MnS spheres with γ/α HPJ is achieved, which shows temperature-dependent structure, morphology and composition evolution. Besides, theoretical calculation indicates that the interface of γ/α HPJ shows higher ion absorption ability and electronic conductivity than pure γ-MnS, as well as the lowest ion diffusion energy barrier. When act as electrode materials for SIBs, the HPJ-modified MnS shows more excellent electrochemical performance than any pure phases (491.5 mA h g−1 at 100 mA g−1, 362.9 mA h g−1 after 1000 cycles at 5000 mA g−1, 261.6 mA h g−1 at 10000 mA g−1). This work puts forward a novel HPJ modification for MnS, and this strategy may develop into a universal solution for other polymouphous electrode materials.