Synthesis Of Two Vanadium-Based Materials And Their Performance In Zinc Ion Batteries

The ever-growing demand for large-scale energy storage applications has aroused extensive research interest on numerous innovative and efficient energy storage devices.Aqueous Zn-based batteries are considered as worthwhile candidates.Based on this,it’s imperative to search for cathode materials with high energy density,great rate capacity,significant power density and satisfying cycling stability.Vanadium-based materials provide a broad space for the development of new energy storage technology,which are characterized by abundant vanadium valence,easy deformation of V-O polyhedra and adjustable chemical composition,thus considered as good candidates for cathodes of zinc ion battery.In this paper,vanadium-based materials V₂O₃ and Zn V₂O₄ are selected as the research objects to study the effects of grain size,carbon coating and recombination on zinc ion diffusion rate,electron conductivity and electrochemical performance.The following content is what we have researched:1.The in situ electrochemical oxidation of V₂O₃-C enhances electrochemical performance of zinc-ion battery.We report the synthesis of V₂O₃-C composite via hydrothermal carbonization.Electrochemical tests confirmed that as-synthesized electrode exhibits good electrochemical performance.Ex-situ tests demonstrate that V₂O₃ undergo an in-situ electrochemical oxidation to layered V₅O₁₂·6H₂O that offers more ion diffusion pathways and accelerates Zinc ions diffusion kinetics,thus enhancing rate performance.2.Optimization of calcination temperature of mesoporous spinel structure Zn V2O4 improves the performance of zinc ion batteries.The mesoporous Zn V2O4cathode material with spinel structure was synthesized by solvothermal technique and calcination at different temperatures.In addition,the effect of calcination temperature on the performance of the cathode material zinc ion battery was studied.The initial discharge capacities are 263,393 and 308 m A h g^-1 at 700,800 and 900℃,respectively.After 120 cycles,ZVO-800 cathode can retain a discharge capacity of231 m A h g^-1 at 100 m A g^-1,and the Coulomb efficiency is up to 99%.In addition,the ZVO-700 and ZVO-900 electrodes retain 108 m A h g^-1 and 127 m A h g^-1,with retention rates of 49%and 41%,respectively.In addition,the ZVO-800 sample possesses large specific surface area and large aperture,and exhibits good electrochemical performance,which is higher than the ZVO-700 and ZVO-900samples.