Selenium-Integrated MoO3 Composite Cathode for Rechargeable Magnesium Batteries.

Abstract

Owing to their high volumetric capacity, potential for low-dendrite metal deposition, and abundance of natural magnesium, rechargeable magnesium batteries (RMBs) have garnered significant interest as potential substitutes for lithium-based systems. Nevertheless, sluggish Mg2+ diffusion and the polyselenide shuttle effect in selenium-based cathodes continue to restrict their practicality. In this work, a Se-MoO3 composite cathode was prepared by solvothermal synthesis of a MoSe2 precursor followed by annealing in air. Compact MoSe2 nanosheets were annealed to create an open hierarchical Se-MoO3 architecture composed of vertically oriented nanosheets associated with MoO3 nanoribbons. The Se-MoO3 cathode delivers 312 mAh g-1 at cycle 80 at 200 mA g-1. At 500 mA g-1, the capacity reaches 237 mAh g-1 at cycle 79 and decreases to 76.8 mAh g-1 at cycle 500. Ex situ measurements reveal reversible changes in the Mo and Se chemical states during cycling, supporting the participation of both components in charge storage. Although the close association between the Se-containing phase and MoO3 may influence the electrochemical response, the present data do not directly establish interface-specific polyselenide adsorption or catalytic conversion. Overall, this work emphasizes compositional and architectural modification as a viable approach for enhanced magnesium-ion storage.

Abstract as supplied by the indexing source. © the authors / publisher.