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

Oxygen vacancy (Vo) is important in the modification of electrode for rechargeable batteries. However, due to the scarcity of suitable preparation strategy with controllable Vo incorporation, the impact of Vo concentration on the electrochemical performances remains unclear. Thus, in this work, Vo-V2O5-PEDOT (VoVP) with tunable Vo concentration 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 Vo in V2O5, but it also results in a larger interlayer spacing. The as-prepared Vo-V2O5-PEDOT-20.3% with Vo concentration of 20.3% (denoted as VoVP-20) is able to exhibit high capacity of 449 mAh center dot g(-1)at current density of 0.2 A center dot g(-1), with excellent cyclic performance of 94.3% after 6,000 cycles. It is shown in the theoretical calculations that excessive Vo in 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 Vo concentration increases beyond 20.3%. Thus, based on this work, scalable fabrication of high-performance electrode with tunable Vo concentration can be achieved with the proposed strategy.