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

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 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 VO (L-VO) for achieving rapid Mg diffusion kinetics. In terms of the interfacial chemistry, the specific exposed crystal planes in L-VO 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 diffusion. In terms of the coordination structure, the straightened V-O structure in L-VO provides efficient ions diffusion path for accelerating Mg diffusion in the cathode. As a result, the L-VO delivers a high reversible capacity (355.3 mA h g at 0.1 A g) and an excellent rate capability (161 mAh g at 1 A g). 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.