High electro-catalytic graphite felt/Mn O2composite electrodes for vanadium redox flow batteries  

作　　者：Qiang Ma Qi Deng Hang Sheng Wei Ling Hong-Rui Wang Hai-Wen Jiao Xiong-Wei Wu Wen-Xin Zhou Xian-Xiang Zeng Ya-Xia Yin Yu-Guo Guo 

机构地区：[1]College of Science, Hunan Agricultural University, Changsha 410128, China [2]Laboratory of Molecular Nanostructure and Nanotechnology, and Beijing National Laboratory for Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences (CAS), Beijing 100190, China [3]Hunan Province Yin Feng New Energy Co. LTD, Changsha 410000, China

出　　处：《Science China Chemistry》2018年第6期732-738,共7页中国科学（化学英文版）

基　　金：supported by the Ministry of Science and Technology of China (2016YFA0202500);the National Natural Science Foundation of China (51772093);the National key Research and Development Program of China (2017YFD0301507)

摘　　要：A mild and simple synthesis process for large-scale vanadium redox flow batteries(VRFBs)energy storage systems is desirable.A graphite felt/Mn O_2(GF-MNO)composite electrode with excellent electrocatalytic activity towards VO^(2+)/VO_2^+redox couples in a VRFB was synthesized by a one-step hydrothermal process.The resulting GF-MNO electrodes possess improved electrochemical kinetic reversibility of the vanadium redox reactions compared to pristine GF electrodes,and the corresponding energy efficiency and discharge capacity at 150 m A cm^(-2)are increased by 12.5%and 40%,respectively.The discharge capacity is maintained at 4.8 A h L^(-1)at the ultrahigh current density of 250 m A cm^(-2).Above all,80%of the energy efficiency of the GF-MNO composite electrodes is retained after 120 charge-discharge cycles at 150 m A cm^(-2).Furthermore,these electrodes demonstrated that more evenly distributed catalytic active sites were obtained from the Mn O_2particles under acidic conditions.The proposed synthetic route is facile,and the raw materials are low cost and environmentally friendly.Therefore,these novel GF-MNO electrodes hold great promise in large-scale vanadium redox flow battery energy storage systems.A mild and simple synthesis process for large-scale vanadium redox flow batteries（VRFBs）energy storage systems is desirable.A graphite felt/Mn O2（GF-MNO）composite electrode with excellent electrocatalytic activity towards VO2＋/VO2＋redox couples in a VRFB was synthesized by a one-step hydrothermal process.The resulting GF-MNO electrodes possess improved electrochemical kinetic reversibility of the vanadium redox reactions compared to pristine GF electrodes,and the corresponding energy efficiency and discharge capacity at 150 m A cm-2are increased by 12.5%and 40%,respectively.The discharge capacity is maintained at 4.8 A h L-1at the ultrahigh current density of 250 m A cm-2.Above all,80%of the energy efficiency of the GF-MNO composite electrodes is retained after 120 charge-discharge cycles at 150 m A cm-2.Furthermore,these electrodes demonstrated that more evenly distributed catalytic active sites were obtained from the Mn O2particles under acidic conditions.The proposed synthetic route is facile,and the raw materials are low cost and environmentally friendly.Therefore,these novel GF-MNO electrodes hold great promise in large-scale vanadium redox flow battery energy storage systems.

关 键 词：VRFB one-step hydrothermal graphite felt manganese dioxide composite electrode 

分 类 号：TM912[电气工程—电力电子与电力传动]