Investigating the Surprising Electrochemical Dynamics of Zinc Battery Systems' Lithium Vanadium Phosphate Electrodes

The low cost and high safety of zinc-ion batteries (ZIBs) have attracted significant attention as a potential alternative to lithium-ion batteries (LIBs). Nevertheless, the commercialization of ZIBs continues to face obstacles, principally because to the lack of electrode materials that provide enough energy density. This research aims to investigate the potential of β-LiVOPO₄ as a cathode for high-energy and high-power zinc-ion batteries (ZIBs) owing to its strong three-dimensional structural framework and high operating potential. More precisely, we successfully obtained a significant operating voltage of 1.61 V compared to the standard Zn/Zn²⁺ reference electrode for β-LiVOPO₄. The cathode exhibited a discharge capacity of 114.1 mA h g⁻¹ at a current density of 100 mA g⁻¹, demonstrating significant cyclability and rate performance. The storage mechanism of the β-LiVOPO₄ cathode was investigated using a variety of characterization techniques, such as in situ synchrotron X-ray diffraction (XRD), ex-situ X-ray absorption spectroscopy, ex situ XRD, and theoretical calculations. A reversible and stable phase transition was maintained during cycling by recurrent Li⁺/Zn²⁺ (de)insertion and capacitive-based surface reactions. This enhanced the electrochemical efficacy of β-LiVOPO₄ when employed as a ZIB cathode.