Magnesium batteries have emerged as a promising alternative to lithium-ion batteries due to their theoretical high energy density and abundant magnesium resources. Vanadium dioxide, VO2(B), has been reported as a high-capacity cathode material for magnesium batteries. However, the electrochemical intercalation mechanism requires further elucidation due to a limited understanding of the structure-property relationship. In this study, we re-evaluated the magnesium storage capability of the material, with a particular focus on the influence of water content in nonaqueous electrolytes. The higher discharge capacity of 250 mAh g(-1) is achieved exclusively in the wet electrolyte with 650 ppm water content. A significantly lower capacity of 51 mAh g(-1) was observed in the dry electrolyte solution containing 40 ppm water content. Through X-ray structural and elemental analyses, as well as magnesium-ion diffusion pathway analysis using bond-valence-energy-landscape calculations, the restricted capacity was clarified by examining the reaction mechanism. According to this study, the impressive capacity of magnesium-ion battery cathodes may be exaggerated due to the involvement of non-magnesium-ion insertion unless the electrolytes & PRIME; water content is appropriately regulated.
Magnesium; calcium; and zinc ion batteries; lithium all-solid-state batteries; Inorganic materials discovery; Solid state chemistry; Crystallography; Mg; Ca; Zn 이온 이차전지; 리튬 전고체전지; 신 무기재료 합성; 고체화학; 결정화학