Broad temperature adaptability of vanadium redox flow battery-part 4： Unraveling wide temperature promotion mechanism of bismuth for V2＋/V3＋ couple

摘要

cqvip:Vanadium flow battery(VFB)is a fast going and promising system for large-scale stationary energy storage.However,drawbacks such as low power density and narrow temperature window caused by poor catalytic activity of graphite felt(GF)electrodes limit its worldwide application.In this paper,bismuth,as a low-cost,no-toxic and high-activity electrocatalyst,is used to modify the thermal activated GF(TGF)via a facile hydrothermal method.Bismuth can effectively inhibit the side reaction of hydrogen evolution in wide temperature range,while promoting the V^(2+)/V^(3+)redox reaction.As a result,the VFB assembled with Bi/TGF as negative electrode demonstrates outstanding rate performance under the current density up to 400 mA cm^(-2),as well as a long-term stability over 600 charging/discharging cycles at a high current density of 150 mA cm^(-2).Moreover,it also shows excellent temperature adaptability from-10°C to50°C and high durability for life test at the temperature of 50°C.