Oxygen‐Vacancy‐Reinforced Vanadium Oxide/Graphene Heterojunction for Accelerated Zinc Storage with Long Life Span

Abstract Vanadium trioxide (V 6 O 13 ) cathode has recently aroused intensive interest for aqueous zinc‐ion batteries (AZIBs) due to their structural and electrochemical diversities. However, it undergoes sluggish reaction kinetics and significant capacity decay during prolonged cycling. Herein, an oxygen‐vacancy‐reinforced heterojunction in V 6 O 13− x /reduced graphene oxide (rGO) cathode is designed through electrostatic assembly and annealing strategy. The abundant oxygen vacancies existing in V 6 O 13− x weaken the electrostatic attraction with the inserted Zn 2+ ; the external electric field constructed by the heterointerfaces between V 6 O 13− x and rGO provides additional built‐in driving force for Zn 2+ migration; the oxygen‐vacancy‐enriched V 6 O 13− x highly dispersed on rGO fabricates the interconnected conductive network, which achieves rapid Zn 2+ migration from heterointerfaces to lattice. Consequently, the obtained 2D heterostructure exhibits a remarkable capacity of 424.5 mAh g −1 at 0.1 A g −1 , and a stable capacity retention (96% after 5800 cycles) at the fast discharge rate of 10 A g −1 . Besides, a flexible pouch‐type AZIB with real‐life practicability is fabricated, which can successfully power commercial products, and maintain stable zinc‐ion storage performances even under bending, heavy strikes, and pressure condition. A series of quantitative investigation of pouch batteries demonstrates the possibility of pushing pouch‐type AZIBs to realistic energy storage market.