Viologen-Decorated TEMPO for Neutral Aqueous Organic Redox Flow Batteries

作     者：Shuzhi Hu Liwen Wang Xianzhi Yuan Zhipeng Xiang Mingbao Huang Peng Luo Yufeng Liu Zhiyong Fu Zhenxing Liang 

作者机构：Key Laboratory of Fuel Cell Technology of Guangdong ProvinceSchool of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510641China School of Materials Science and EngineeringSun Yat-sen UniversityGuangzhou 510275China 

出 版 物：《Energy Material Advances》 (能源材料前沿（英文）)

年 卷 期：2021年第2021卷第1期

页      面：90-97页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070303[理学-有机化学] 0703[理学-化学] 

基　　金：the National Natural Science Foundation of China(21975081 and 21905114) 

主　　题：electrolyte kinetics eliminate 

摘      要：A novel electroactive organic molecule,viz.,1-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)-1′-(3-(trimethylammonio)propyl)-4,4′-bipyridinium trichloride((TPABPy)Cl3),is synthesized by decorating 2,2,6,6-tetramethylpiperidin-1-oxyl(TEMPO)with viologen,which is used as the positive electrolyte in neutral aqueous redox flow battery(ARFB).Extensive characterizations are performed to investigate the composition/structure and the electrochemical behavior,revealing the favorable effect of introducing the cationic viologen group on the electroactive *** findings are as ***,the redox potential is elevated from+0.745V for TEMPO to+0.967V for decorated TEMPO,favoring its use as the positive *** an elevation originates from the electron-withdrawing effect of the viologen unit,as evidenced by the nuclear magnetic resonance and single crystal structure ***,linear sweep voltammetry reveals that the diffusion coefficient is 2:97×10^(−6) cm^(2) s^(−1),and the rate constant of the one-electron transfer process is 7:50×10^(−2) cm s^(−1).The two values are sufficiently high as to ensure low concentration and kinetics polarization losses during the battery ***,the permeability through anion-exchange membrane is as low as 1:80×10^(−11) cm^(2) s^(−1).It is understandable as the positive-charged viologen unit prevents the molecule from permeating through the anion exchange membrane by the Donnan ***,the ionic nature features a decent conductivity and thus eliminates the use of additional supporting ***,a flow battery is operated with 1.50M(TPABPy)Cl3 as the positive electrolyte,which affords a high energy density of 19.0WhL-1 and a stable cycling performance with capacity retention of 99.98%per cycle.