Endowing V6O13/CeVO4 heterojunction with substantial improvements on zinc ion storage performance

The slow ion diffusion stemming from the high charge density of Zn2+ renders zinc-ion batteries (ZIBs) low reaction kinetics and cyclic stability. Herein, a series of nanoflake-shaped V6O13/CeVO4 composites containing oxygen vacancies with different feed ratios of cerium and vanadium are synthesized by one-step hydrothermal method. The design of V6O13-CeVO4 heterostructure can generate the built-in electric field, offering an additional driving force to accelerate electron transfer and thus enhance its overall electrical conductivity. Significantly, the enhanced adsorption energy of Zn2+ on the heterointerfaces is beneficial to stimulate the fast reaction kinetics. The induced abundant oxygen vacancies serve as the ample active sites to facilitate ion transport. Therefore, the construction of heterojunction and vacancy can be considered as a dual-drive strategy to promote the electrochemical performance. As a result, the ZIBs cathode based on the optimal V6O13/CeVO4-6 heterostructure exhibits an ultra-high capacity (280 mA h g−1 after 300 cycles at 1 A/g), rate capability, and long-cycle life (206.4 mA h g−1 after 4000 cycles at 10 A/g with a 78.2% capacity retention). Together with the deep investigation on the storage mechanism and kinetics analysis of Zn2+ through a series of ex situ characterizations and theoretical calculation, this study is valuable for the development of new vanadium-based cathodes for high-performance ZIBs.