Abstract
Abstract
Aqueous magnesium ion batteries (AMIBs) have attracted widespread attention due to their high safety and low cost. However, conventional V2O5 material suffers from issues such as narrow interlayer distance, slow Mg2+ diffusion kinetics, and severe interfacial side reactions during Mg2+ insertion and extraction, resulting in insufficient capacity and cycling performance. This work presents a dual-function organic molecule doping strategy, in which ethylenediaminetetraacetic acid (EDTA) molecules are doped into a layered V2O5 to construct an EDTA-V2O5 (EVO) composite material. EDTA doping increases the interlayer distance and lowers the Mg2+ diffusion energy barrier. More importantly, it changes the surface properties of the material, indirectly regulates the inner Helmholtz plane (IHP) and reconstructs the electric double layer (EDL) structure at the electrode/electrolyte interface. Through theoretical calculations and characterizations, it is revealed that EDTA doping enhances the interfacial stability of V2O5 and suppresses the hydrogen evolution side reaction. This synergistic strategy between the body-doping and interface regulation enables 1-EVO (1-EDTA-V2O5) to maintain a capacity retention rate of 87.7 % after 2000 cycles at a current density of 1 A g-1, providing new insights for the development of highly diffusion kinetics, long-life AMIBs cathode.