Hollow VO microspheres anchored on graphene as advanced cathodes for aqueous zinc-ion batteries.

Vanadium dioxide-based materials have been proved to be promising cathodes for aqueous zinc ion batteries (AZIBs) due to their cost-effectiveness and high theoretical specific capacity; nevertheless, the low electronic conductivity and poor cycle stability restrict their application. Herein, hollow VO microspheres anchored on graphene oxide (H-VO@GO) are synthesized via a facile simple hydrothermal reaction as high-performance cathodes for AZIBs. The hollow micromorphology of the material provides a large specific surface area and effectively alleviates the volume changes during cycling, while the anchoring of VO on graphene oxide greatly improves the electronic conductivity and inhibits the agglomeration and pulverization of the material. Resulting from the combination of unique micromorphology and graphene oxide anchoring, the as-prepared H-VO@GO exhibits the impressive specific capacity of 400.1 mAh/g at 0.5 A/g and excellent cycling performance with 96.1 % of capacity retention after 1500 cycles at 10 A/g. This investigation provides a use reference for designing high-performance cathodes materials for AZIBs by optimizing the microstructure of electrode materials.