3D Porous Sponge-Inspired Electrode for High-Energy and High-Power Zinc-Ion Batteries

Aqueous rechargeable zinc-ion batteries (ZIBs) are attractive alternatives for large-scale sustainable energy storage devices owing to their high energy density, reliability, environmental friendliness, and safety. However, their practical application is largely impeded by the limited selection of suitable cathodes, which often leads to inadequate cyclic lifespan and unsatisfactory rate capability. Here, a three-dimensional (3D) porous interconnected aerogel comprised of an ultrathin VO2 sheet coated with amorphous carbon is demonstrated as a cathode material for ZIBs. Benefiting from the synergistic merits of favorable ultrathin features of the VO2 sheet and the large accessible surface area of the 3D porous structure, the carbon/VO2 (CVO) composite electrode displays a good electrochemical performance with a high capacity of 388 mAh g-1 at 0.1 A g-1, good rate capability, and very long cycling life (80% capacity retention over 1000 cycles at 5.0 A g-1). The elemental and structural characterization identifies the highly reversible Zn2+-ion de/intercalation reaction mechanism that supports its excellent performance. The three-dimensional (3D) carbon-coated metallic oxide strategy brings opportunities for the development of high-performance aqueous rechargeable ZIBs and potentially other batteries for a wide range of applications.