Coherent SnS2/NiS2 hetero-nanosheet arrays with fast charge transfer for enhanced sodium-ion storage

Layered SnS2 has attracted extensive attention as promising anode material for sodium-ion storage owing to its high theoretical specific capacity. However, the practical performance is always hindered by its inferior rate capability and severe capacity fading. Herein, a novel coherent SnS2/NiS2 hetero-nanosheet arrays on carbon cloth (SnS2/NiS2@CC) is fabricated through a facile one-step solvothermal method by controlling the synchronous growth of SnS2 and NiS2. Benefiting from the strong coupling effect between SnS2 and NiS2, and thus the markedly elevated electrical conductivity and charge transfer rate for sodiation/desodiation reaction, such composite exhibits significantly enhanced performance than its pure SnS2 counterpart as the anode for sodium-ion battery, presenting a high reversible capacity (909.2 mA h g−1 of the fifth cycle at 200 mA g−1), excellent rate capability (360 mA h g−1 at 5 A g−1) and satisfying cycling stability (588.9 and 343.2 mA h g−1 at 0.5 and 2 A g−1 after 100 cycles, respectively). Moreover, the measured Na+ diffusion coefficient for such SnS2/NiS2@CC electrode is almost two orders of magnitude higher than that of pure SnS2@CC. Such heterogeneous structuring for enhancing the rate performance could offer an effectively alternative way for the development of advanced electrode materials for energy storage devices.