V ₂ O ₅ /Mesocarbon Microbeads Composites with Oxygen Vacancies as Cathodes for Sodium-Ion Batteries

The multivalent, low-cost, and high-capacity characteristics of vanadium-based oxides have attracted much attention in the study of cathode materials for sodium-ion batteries (SIBs). Nonetheless, the depressed diffusion kinetics and poor electrical conductivity limit the application, which is mainly due to the large radius of the sodium ion. To solve these problems, we obtained the cathode material with enriched oxygen vacancies by compositing mesocarbon microbeads (MCMB) with V 2 O 5 to achieve more sodium storage sites and electrical conductivity. In particular, V 2 O 5 /MCMB as cathodes for SIBs delivers 99.65 mAh g –1 at 0.5 A g –1 and maintains 91.67% of their initial capacity after 60 cycles. It also has a remarkable rate performance and excellent diffusion coefficient (1.59 × 10 –9 –2.0 × 10 –12 cm 2 s –1 ). It provides innovative insights for the further progress of cathode materials used in SIBs.