Electric-field harmony in V2C/V2O5 heterointerfaces toward high-performance aqueous Zn-ion batteries

The infancy-stage heterointerfaces cathode materials typically avoid strong electrostatic interactions and low diffusion rates with divalent Zn2+, leading to fast Zn2+ intercalation kinetics. Herein, high-performance V2C/V2O5 heterostructures with electric-field harmony are firstly constructed through synchronous O2 plasma strategy. As the core of this strategy, oxygen has a wide range of sources and no toxicity, which is compatible with high-safety Zn-ion batteries. Moreover, different phases at the V2C/V2O5 heterointerfaces generate built-in electric fields (BEFs), lowering the energy barrier for ion migration, which is beneficial to the migration of Zn2+. In addition, DFT theoretical calculations show that the energy band gaps of V2C/V2O5 heterostructures are lower than those of V2C and V2O5, further facilitating the surface reaction kinetics and accelerates the charge transfer. With reversible structural evolution, the formation of BEFs in the V2C/V2O5 heterointerfaces boost electron/ion diffusion and reduce charge transfer resistances. V2C/V2O5 heterostructures can exhibits a capacity of 232 mAh g−1 at 25 A g−1 with remarkable energy and power densities (322 Wh kg−1/19.375 kW kg−1). This work provides important insights into the design of high-performance materials for advanced ZIBs.