Investigations On K⁺ Intercalated V₆O₁₃ As The Cathode For Aqueous Zn-ion Batteries

The development of human society is seriously restricted by fossil fuels and environmental problems.Renewable and clean energy such as solar,wind and tidal energy are expected to become the major energy sources in the future.To efficiently utilize renewable and clean energy,converting them into electrical energy is one of the main methods currently.So,it is necessary to develop energy storage devices which could be produced in large-scale with high safety and low cost.Vanadium-based oxides with suitable channels for Zn²⁺migration are promising kinds of cathodes for AZIBs.In order to further enhance the long cycle life and high-rate performance,in this paper,the chemical modification of V₆O₁₃and（NH₄）₂V₁₀O₂₅·8H₂O by K⁺intercalated has been investigated by theoretical simulation and experimental methods.The intercalated K⁺expands the（001）space and facilitates the migration of Zn²⁺,improving the stability,high-rate performance,and long cycle life during charging and discharging.（1）K⁺intercalated V₆O₁₃(K-V₆O₁₃)is prepared by hydrothermal method.The results of XRD,XPS and EDS indicate that K⁺are uniformly intercalated into the V₆O₁₃.Electrochemical measurements show that the specific capacities of K-V₆O₁₃are 367 and 198.8 mAh g^-1at current density of 0.5 A g^-1and 10 A g^-1,respectively.The capacity retention is 90%after 2000 cycles at 10 A g^-1.（2）K⁺intercalated（NH₄）₂V₁₀O₂₅·8H₂O（K-NVO）is prepared by chemical deposition.Electrochemical measurements show that the specific capacities of K-NVO are 406.5 and 205.4 mAh g^-1at current density of 0.5 A g^-1and 10 A g^-1,respectively.The capacity retention is 87%after 1000 cycles at 10 A g^-1.This paper suggests that K⁺interacted method could effectively improve the electrochemical performances of V₆O₁₃and（NH₄）₂V₁₀O₂₅·8H₂O as the cathodes for AZIBs and provides theoretical guidance for the development of novel cathode materials for AZIBs.