Cation pre-intercalation and oxygen vacancies in vanadium oxide for synergistically enhanced high-rate and stability for zinc-ion batteries

Vanadium oxides are promising cathodes for zinc-ion batteries (ZIBs), but their low structural stability and sluggish Zn2+ ions/electron migration kinetics limit their rate performance and cyclic durability. Herein, a nickel-ions pre-intercalated and oxygen-defective vanadium oxide (Od-NiVO) was synthesized. The oxygen vacancies increase V4+ species and trigger the unbalanced charge distribution, optimizing the conductivity. Besides, the oxygen vacancies weaken the electrostatic interactions to facilitate the Zn2+ migration kinetics and increase more reversible sites. Moreover, the pre-intercalated Ni2+ enlarges the interlayer spacing and act as a pillar to stablize the structure. Therefore, the Od-NiVO cathode exhibits a superior discharge capacity (300.1 mAh g−1 at 0.2 A g−1), excellent rate capability (175.0 mAh g−1 at 5 A g−1) and a stable cyclic durability at 5 A g−1 with capacity retention of 94% over 1000 cycles. This multi-structure co-design strategy opens up a new route for developing high-performance ZIBs.