Dominant role of wettability in improving the specific capacitance

作     者：Tongtong Liu Kai Wang Yongxiu Chen Shuangliang Zhao Yongsheng Han 

作者机构：State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences School of Chemical Engineering University of Chinese Academy of Sciences State Key Laboratory of Chemical Engineering and School of Chemical Engineering East China University of Science and Technology 

出 版 物：《Green Energy & Environment》 (绿色能源与环境（英文版）)

年 卷 期：2019年第4卷第2期

页      面：171-179页

核心收录：

学科分类：08[工学] 0807[工学-动力工程及工程热物理] 

基　　金：financial support from National Natural Science Foundation of China(91534123,91834303,U1862117) supported by the State Key Laboratory of Multiphase Complex Systems(MPCS-2017-A-01) support by State key laboratory of Multiphase Complex Systems(MPCS)Facility Upgradation Program 

主　　题：Supercapacitor Energy density Specific capacitance Effective surface area Wettability 

摘      要：Here we report a strategy to enhance the energy density of supercapacitors by increasing the utilization rate of the specific surface area(SSA)via wettability improvement. The nonporous gold(NPG) film is used as the electrodes and the ionic liquid [EMIM]BF4 is the electrolyte. When the electrode is coated by paraffin, an increase of the contact angle leads to a remarkable reduction of the specific capacitance. While when acetonitrile is added into the electrolyte, the contact angle is decreased and the utilization rate of SSA is improved, which results in an increase of the specific capacitance. The addition of isopropyl acetate into the electrolyte leads to a further increase of the specific capacitance. To generalize the role of the wettability in improving the energy density, a carbon-based electrode is evaluated in the solution of potassium hydroxide. An addition of propyl alcohol into the potassium hydroxide solution leads to an increase of the specific capacitance, as well as a long-term stability of the supercapacitor. The role of conductivity in this study is excluded by designing experiments. This paper highlights the significance of wettability in determining the specific capacitance, showing an alternative to improve the energy density of supercapacitors.