Vanadium phosphate as a promising high-voltage magnesium ion (de)-intercalation cathode host

Abstract

Magnesium batteries (MBs) have been considered as one of the most promising safe and low cost energy storage systems. Herein, vanadium phosphates, prepared by the electrochemical de-lithiation of Li₃V₂(PO₄)₃, are investigated as a high-voltage cathode host for Mg²⁺ (de)-intercalation. The reversible (de)-intercalation of Mg²⁺ into (from) the host structure of V₂(PO₄)₃ are verified by the comprehensive analysis of the results from the electrochemical tests, synchrotron X-ray diffraction and absorption, and inductively coupled plasma measurements. Its exceptional high average working voltage (∼3.0 V vs. Mg/Mg²⁺) surpasses other reported values of cathode hosts for MBs.