MoSe₂ hollow nanospheres with expanded selenide interlayers for high-performance aqueous zinc-ion batteries

Transition metal dichalcogenides (TMDs) as materials for aqueous zinc-ion batteries (ZIBs) have received a lot of interest because of their large theoretical capacity and unique layered structure. However, the sluggish kinetics and inferior cyclic stability limit the usefulness of ZIBs. In the present investigation, the interlayer spacing enlarged MoSe₂ hollow nanospheres comprised of nanosheets with ultrathin shells have been successfully synthesized through a combined strategy of template assistance and anion-exchange reaction. The hierarchical ultrathin nanosheets and hollow structure effectively suppress the agglomeration of pure nanosheets and ameliorate volume fluctuations induced by ion migration during (dis)charging/charging. The interlayer expansion provides good channels for the transport of Zn²⁺ ions and speeds up the insertion/extraction of Zn²⁺. In addition, in-situ carbon modification can significantly improve electronic conductivity. Therefore, the electrode prepared from MoSe₂ hollow nanospheres with enlarged interlayer spacing not only exhibits outstanding cycle stability (capacity retention of 94.5% after 1600 cycles) but also exhibits high-rate capability (266.1 mA h g^-1 at 0.1 A g^-1 and 203.6 mA h g^-1 at 3 A g^-1). This work could provide new insights into the design of cathode using TMDs of hollow structure for Zn²⁺ storage.