V₂O₃ with Se-Enhanced d-p Orbital Hybridization Toward Highly Stable Aqueous Zinc Batteries under 10 A g^-1.

Abstract

Vanadium-based compounds are a reliable and promising cathode material for aqueous zinc ion batteries. However, the rapid insertion/extraction of Zn²⁺ at high current densities triggers irreversible structural degradation and slow ion diffusion kinetics, leading to poor cycling stability. Herein, highly conductive Se is doped into a carbon skeleton of V₂O₃, realizing the orbital interaction between V 3d and Se 4p orbitals. Density functional theory calculations verify that the strong d-p orbital hybridization upshifts the d-band center of V, optimizes the charge distribution, and reduces the Zn²⁺ and H⁺ adsorption energies. Furthermore, the robust V─Se covalent network in the Se-V₂O₃@C electrode significantly enhances the electrode's redox activity and conductivity, resulting in high specific capacity and ultra-long cycle life. Therefore, the Se-V₂O₃@C-650 electrode exhibits a high capacity of 460.87 mAh g^-1 at 0.1 A g^-1. When the current density is 10 A g^-1, the capacity reaches 168.32 mAh g^-1 after 10 000 cycles, with a 73.8% capacity retention after 20 000 cycles, which exceeds the reported electrodes. This work presents new insights for constructing high-performance AZIB cathodes by establishing the mechanism of action between d-p orbital hybridization and electrochemical performance.