Improvement of Electrochemical Performances of Electrochromic-Zinc Ion Batteries System Utilizing V4+-V2O5 As a Cathode

Abstract

Recently, many countries are practicing carbon neutrality to lower greenhouse gas emissions to "zero" by 2050. Therefore, zinc ion batteries (ZIBs) have been increasing attention as next-generation batteries due to low cost and high volumetric energy density. In addition, since ZIBs utilize a human-friendly water-based electrolyte, ZIBs has been proposed as an alternative to wearable energy storage systems. Above all, the electrochromic – ZIB system is gaining popularity as the next generation storage technology because it can visualize charging and discharging. Vanadium oxide(V2O5), one of the cathode materials of electrochromic ZIB, exhibits excellent electrochemical characteristics with excellent rate performance through intercalation in the layered structure. However, because of V2O5’s poor electronic and ionic conductivities, it is necessary to improve the structure improvement for increasing energy density.To solve this problem, mixed multiple oxidation states of vanadium are essential to ZIB cathode. This mixed valence states are contributed to increase electrochemical performance and specific capacity.1 V4+-V2O5 exhibit higher electrochemical activity, faster ion transport, better electrical conductivity than Pure V2O5. Also, we can expect that V4+-V2O5 performs outstanding rate capability and long term-cyclic life.In this study, we developed V4+-V2O5 based electrochromic-ZIB cathode to enhance electrochemical performance controlling the temperature for vanadium reduction heat treatment in H2 gas atmosphere. Furthermore, it will be determined whether vanadium oxide is suitable for electrochromic. Between the yellow V2O5 and the black Vanadium-based compounds, an appropriate point with excellent electrochemical and electrochromic properties will be found.