Facile preparation of urchin-like morphology V2O3-VN nano-heterojunction cathodes for high-performance Aqueous zinc ion battery

Rechargeable aqueous zinc ion batteries (RAZIBs) are of interest for energy storage in smart grids. However, slow Zn2+ diffusion kinetics, insufficient active sites, and poor intrinsic conductivity are always challenging to exploit the huge potential of the batteries. Here, we prepare V2O3-VN nano-heterojunction composites with sea urchin-like morphology as the cathode for AZIBs. The electrode achieves high capacities (e.g., 0.1 A g-1, 532.6 mAh g-1), good rate and cycle performance (263.4 mAh g-1 at 5 A g-1 current density with 90.8% capacity retention). Detailed structural analyses suggest that the V2O3-VN composite is composed of different crystal planes of V2O3 and VN, which form an efficient heterogeneous interfacial network in the bulk electrode, accounting for its good electrochemical properties. Theoretical calculations reveal that compared with V2O3, VN and physically mixed V2O3/VN, the V2O3-VN heterostructure exhibits good cation adsorption and electrode conductivity, thereby accelerating the charge carrier mobility and electrochemical activity of the electrode. Moreover, ex-situ characterization techniques are utilized to investigate the zinc storage mechanism in detail, providing new ideas for the development of AZIBs cathode materials through the construction of heterojunction structures.