Tunable oxygen vacancy concentration in vanadium oxide as mass-produced cathode for aqueous zinc-ion batteries

Oxygen vacancy(Vö)is important in the modification of electrode for rechargeable batteries.However,due to the scarcity of suitable preparation strategy with controllable Vöincorporation,the impact of Vöconcentration on the electrochemical performances remains unclear.Thus,in this work,Vö-V_(2)O_(5)-PEDOT(VöVP)with tunable Vöconcentration is achieved via a spontaneous polymerization strategy,with the capability of mass-production.The introduction of poly(2,3-dihydrothieno-1,4-dioxin)(PEDOT)not only leads to the formation of Vöin V_(2)O_(5),but it also results in a larger interlayer spacing.The as-prepared Vö-V_(2)O_(5)-PEDOT-20.3%with Vöconcentration of 20.3%(denoted as VöVP-20)is able to exhibit high capacity of 449 mAh·g^(−1) at current density of 0.2 A·g^(−1),with excellent cyclic performance of 94.3% after 6,000 cycles.It is shown in the theoretical calculations that excessive Vöin V_(2)O_(5) will lead to an increase in the band gap,which inhibits the electrochemical kinetics and charge conductivity.This is further demonstrated in the experimental results as the electrochemical performance starts to decline when Vöconcentration increases beyond 20.3%.Thus,based on this work,scalable fabrication of high-performance electrode with tunable Vöconcentration can be achieved with the proposed strategy.