Carbon Superstructure-Supported Half-Metallic V₂O₃ Nanospheres for High-Efficiency Photorechargeable Zinc Ion...

Photorechargeable zinc ion batteries (PZIBs), which can directly harvest and store solar energy, are promising technologies for the development of a renewable energy society. However, the incompatibility requirement between narrow band gap and wide coverage has raised severe challenges for high-efficiency dual-functional photocathodes. Herein, half-metallic vanadium (III) oxide (V₂O₃) was first reported as a dual-functional photocathode for PZIBs. Theoretical and experimental results revealed its unique photoelectrical and zinc ion storage properties for capturing and storing solar energy. To this end, a synergistic protective etching strategy was developed to construct carbon superstructure-supported V₂O₃ nanospheres (V₂O₃@CSs). The half-metallic characteristics of V₂O₃, combined with the three-dimensional superstructure assembled by ultrathin carbon nanosheets, established rapid charge transfer networks and robust framework for efficient and stable solar-energy storage. Consequently, the V₂O₃@CSs photocathode delivered record zinc ion storage properties, including a photo-assisted discharge capacities of 463 mA ⋅ h ⋅ g^-1 at 2.0 A ⋅ g^-1 and long-term cycling stability over 3000 cycles. Notably, the PZIBs assembled using V₂O₃@CSs photocathodes could be photorecharged without an external circuit, exhibiting a high photo conversion efficiency (0.354 %) and photorecharge voltage (1.0 V). This study offered a promising direction for the direct capture and storage of solar energy.