Coupling Manipulation of Interfacial Chemistry and Coordination Structure in Vanadium Oxides Enables Rapid Magnesium Ion Diffusion Kinetics

Abstract Rechargeable magnesium batteries (RMBs) are a highly promising energy storage system due to their high volumetric capacity and intrinsic safety. However, the practical development of RMBs is hindered by the sluggish Mg 2+ diffusion kinetics, including at the cathode‐electrolyte interface (CEI) and within the cathode bulk. Herein, we propose an efficient strategy to manipulate the interfacial chemistry and coordination structure in oligolayered V 2 O 5 (L−V 2 O 5 ) for achieving rapid Mg 2+ diffusion kinetics. In terms of the interfacial chemistry, the specific exposed crystal planes in L−V 2 O 5 possess strong electron donating ability, which helps to promote the degradation dynamics of C−F/C−S bonds in the electrolyte, thereby establishing the inorganic‐organic interlocking CEI layer for rapid Mg 2+ diffusion. In terms of the coordination structure, the straightened V−O structure in L−V 2 O 5 provides efficient ions diffusion path for accelerating Mg 2+ diffusion in the cathode. As a result, the L−V 2 O 5 delivers a high reversible capacity (355.3 mA h g −1 at 0.1 A g −1 ) and an excellent rate capability (161 mAh g −1 at 1 A g −1 ). Impressively, the interdigital micro‐RMBs is firstly assembled, exhibiting excellent flexibility and practicability. This work gives deeper insights into the interface and interior ions diffusion for developing high‐kinetics RMBs.