Core-Shell Structure of Polyoxovanadate Coated with Polyaniline for High-Performance Aqueous Zinc-Ion Battery Cathode Materials.

Aqueous zinc-ion batteries (AZIBs) are candidates for energy storage systems due to their high safety, low cost, and high theoretical capacity, whereas their practical application is severely impeded by the slow reaction kinetics and structural instability of the cathode materials. Herein, the core-shell structure of polyoxovanadates {Mn(HO)VO(SO)} (MnVO) coated with polyaniline (PANI) is developed as the cathode material for AZIBs. The tri-dimensional robust MnVO offers abundant active sites and high porosity, and the highly conductive PANI significantly accelerates the electron/ion transfer transport and prevents the dissolution of polyoxovanadates, which effectively enhance reaction kinetics and provide sufficient space for improving Zn storage performance. Consequently, the optimized MnVO@PANI cathode exhibited a high reversible capacity of 413.9 mAh g at 0.1 A g and excellent cyclic stability with 85.4% capacity retention at 10 A g after 1500 cycles.