Defect engineering for achieving multi-electrons storage in VS₄ to enhance magnesium storage performance

Defect engineering acts as an efficiency method to modulate the microstructure and electronic structure of cathode for rechargeable magnesium batteries (RMBs). Owing to rich sulfur (S) vacancies tunes the electronic structure of VS₄ with rich S vacancies (V_S-VS₄), the lower oxidation state of V³⁺ is induced for achieving the V³⁺/V⁴⁺ and V⁴⁺/V⁵⁺ multi-electrons reaction for Mg²⁺ storage. Amorphous structure is also constructed in V_S-VS₄ by chemical vapor deposition (CVD) method under the high temperature for providing fast magnesium ions (Mg²⁺) diffusion channels and expanding inner stress release space to balance the structural stability of multi-electrons reaction process. The simple defect engineering realizes the stable multi-electrons reaction in V_S-VS₄ for enhancing its Mg²⁺ storage performance with higher specific capacity (158.6 mAh·g⁻¹ at 50 mA·g⁻¹), stable cycling performance (capacity retention ratio of 72.7% after 3600 cycles) and the superior rate capability. This work provides electrode designing guidance for achieving stable multi-electrons to fully utilize the bivalent property of multivalence metal batteries.