Achieving fast ion diffusion in aqueous zinc-ion batteries by cathode reconstruction design

• A unique reconstruction strategy via electrochemical charging is proposed. • 1.3 Å increase in interlayer spacing and 90% decrease in energy barriers are achieved. • The exchange of cations and H 2 O molecules process can boost energy storage of layered hosts. • The structural evolution of cathode materials is elaborated during discharge-charge process. Layered vanadium oxides with unique layered framework, as the most promising cathodes for aqueous zinc-ion batteries (AZIBs), can accommodate massive Zn 2+ ingress and offer the expediting pathways for cations diffusion. However, they often suffer from the capacity decaying arising from the gradual degradation of V-O layers interacted by weak van der Waals forces during cycling. Herein, bilayered potassium vanadate nanobelts (KVO NBs) as a representative demonstration are synthesized to implement and investigate electrochemical reconstruction design. In aqueous electrolyte, peculiar reconstruction process further irreversibly expands the interlayer spacing from 9.50 to 10.8 Å and achieves a 90% decrease in activation energy barriers after initial charging, offering insight into the origins of the exceptional capacity in the following cycles. Hence, the as-obtained cathode with robust framework delivers a high capacity of 361 mAh g -1 at 0.2 A g -1 and superior cycling stability of 90.3% for 2000 cycles at 5 A g -1 . In addition, basic zinc salt structural evolution, as well as proton/zinc-ion co-insertion/extraction process have been elucidated clearly during discharge/charge process. This work will provide a new concept toward the interlayer spacing design for layered cathode materials to improve the performance of AZIBs, as well as enrich and perfect zinc storage mechanism.