Dual-Ion Co-Insertion Engineering for Kinetics Enhancement and Stress Regulation in Cu3VS4 Toward Durable Magnesium/Lithium Hybrid Batteries

Abstract

Rechargeable magnesium batteries (rMBs) have tremendous development prospects in the field of energy storage, however, the strong electrostatic interactions induced by divalent Mg2+ give rise to the sluggish diffusion kinetics. Herein, the dual ion co-intercalation strategy is proposed to expedite ion migration in Cu3VS4, achieving elevated specific capacity, transcendent rate capability, and ultra-stable cycling capability. Kinetic analyses combined with DFT calculations indicate that the dual-ion co-insertion can fast charge transfer, reduce the diffusion barrier of Mg2+and optimize the reaction kinetics. Finite element simulations quantitatively verify that dual ion co-intercalation contributes to alleviating magnesiation/lithiation-induced stress in the shell layer and maintains structural integrity from a mechanical standpoint. Ex situ characterizations profoundly illustrates the multistep magnesium/lithium storage mechanisms and the evolution of structure. The proposed cation co-intercalation strategy not only holds promise in opening new insights for high-performance, continuously stable rMBs, but also provides inspiration for multivalent battery systems.