超级电容器
电化学
阳极
阴极
水溶液
材料科学
化学工程
活性炭
析氧
电极
吸附
无机化学
功率密度
碳纤维
化学
复合材料
有机化学
物理化学
物理
工程类
复合数
功率(物理)
量子力学
作者
Meng Chen,Cheng Qian,Yong Qian,Jinxin He,Xia Dong
标识
DOI:10.1016/j.electacta.2020.136046
摘要
Aqueous supercapacitor with the character of cost-effective and environmental-friendly has been regarded as the promising energy storage device. However, the operating voltage of aqueous supercapacitor is usually limited by the electrochemical stability of water, which greatly hinders their application and development. Such a limitation may be surpassed by increasing the over-potential of oxygen evolution reaction and hydrogen evolution reaction. Herein, metal cation inserted MnO2 nanosheets supported on carbon cloth substrate were prepared via electrochemical activation, which can stably work as cathode in an expended positive potential window of 0–1.3 V (vs SCE). To complement this wide potential positive electrode, K+ was adsorbed onto an activated carbon cloth via electrochemical reduction method. As anode, K+ adsorbed activated carbon cloth displayed extended negative potential window of −1.2-0 V (vs SCE) due to the adsorption of K+ effectively prevented the hydrogen evolution reaction. A 2.5 V aqueous asymmetric supercapacitor was assemble based on Na–MnO2@CC cathode and KACC anode, delivering the maximum energy density of 475.7 μWh/cm2 and power density 5 mW/cm2 as well as exceptional cycling performance and excellent flexibility.
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