Drastically Promoting Rate Capability via Dual-Cations Intercalation of VO Enabling Rapid Zinc-Ion Storage.

Layered vanadium pentoxide (VO) has drawn enormous attention as cathode material for aqueous zinc-ion batteries (AZIBs). However, the fragile open-framework and the sluggish Zn migration due to the strong electrostatic interaction between Zn and cathode electrode hinder the development of AZIBs. Here, an effective dual-cations intercalation strategy is employed based on synergistic effect of Mn and Zn, which introduces guest species with robust layered construction and weak electrostatic interaction in the VO bulk. Consequently, the (MnZn)VO (abbreviated to MZVO) electrode exhibits a high reversible capacity of 463 mA h g at 0.1 A g, a high cycling stability (94% of capacity retention after 1000 cycles at 10 A g) and superior rate performance of 256 mAh g at 20 A g. The outstanding performance of MZVO cathode is attributed to the Mn-induced fast migration of Zn transfer and Zn-induced high structural stability conducted by density functional theory (DFT) calculations. The two-phase reaction mechanism of MZVO during Zn (de)interaction is systematically expounded via operando XRD. This study will provide reference for the design of modified layered metal oxides in the future.