钒液流电池石墨毡电极的MWCNTs-COOH-NS修饰  

Graphite felt electrode modified with MWCNTs-COOH-NS for vanadium flow battery

作　　者：李强 王俊楠 孙红 LI Qiang;WANG Junnan;SUN Hong(School of Mechanical Engineering,Shenyang Jianzhu University,Shenyang 110168,Liaoning,China)

机构地区：[1]沈阳建筑大学机械工程学院,辽宁沈阳110168

出　　处：《储能科学与技术》2021年第6期2097-2105,共9页Energy Storage Science and Technology

基　　金：国家自然科学基金项目(51902211,51776131);辽宁省兴辽英才计划项目(XLYC1802045);辽宁省基金项目(lnjc201907)。

摘　　要：聚丙烯腈基石墨毡电极存在电化学活性低等问题,限制了全钒液流电池(VRFB)的发展。为提高VRFB正极侧电极性能表现,研究以硫脲为掺杂源,制备了氮硫共掺杂的羧基化多壁碳纳米管(MWCNTs-COOH-NS)作为VRFB的催化剂。将MWCNTs-COOH-NS修饰到聚丙烯腈基石墨毡电极上,得到复合电极材料。通过扫描电子显微镜(SEM)、比表面积测试(BET)、X射线光电子能谱(XPS)、四探针电导率测试、循环伏安法(CV)、电化学阻抗分析法(EIS)及充-放电循环测试研究了复合电极的表面形态和电化学性能。结果表明,改性后的复合电极提高了比表面积,降低了电池内阻。当电流密度为80 mA/cm^(2)时,电池的能量效率为81.70%,放电容量可以达到782.60 mA·h。在160 mA/cm^(2)的条件下进行充放电测试,电池的能量效率仍可达到72.73%。MWCNTs-COOH-NS修饰的石墨毡电极对正极侧钒离子的氧化还原反应表现出了良好的催化活性和电化学可逆性,并且在充放电测试当中展现出了良好的循环稳定性。本研究有望在一定程度上推动VRFB电极催化剂的发展。The low electrochemical activity of the polyacrylonitrile graphite felt electrode limits the development of all vanadium redox flow battery(VRFB).Nitrogen and sulfur co-doped carboxylic multi-walled carbon nanotubes(MWCNTs-COOH-NS)were prepared as a VRFB catalyst using thiourea as a doping source to improve the performance of positive electrodes in VRFB.Composite electrodes were manufactured by attaching MWCNTs-COOH-NS to polyacrylonitrile graphite felt.Scanning electron microscopy(SEM),specific surface area(BET),X-ray photoelectron spectroscopy(XPS),conductivity measurement,cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS),and charge-discharge tests were used to investigate the surface morphology and electrochemical properties of the composite electrode.According to the results,the composite electrode had a larger surface area and a lower internal resistance.When the current density is 80 mA/cm^(2),the battery's energy efficiency is 81.70%,and the discharge capacity is 782.60 mA·h.Under the condition of 160 mA/cm^(2),the battery's energy efficiency can still reach 72.73%.On the positive side,MWCNTs-COOH-NS modified graphite felt electrode exhibits good catalytic activity and electrochemical reversibility for the redox reaction of vanadium ions.In the charge-discharge test,the cell shows good cycle stability.This study is helpful to promote the development of VRFB electrode catalysts.

关 键 词：全钒液流电池 石墨毡 电极 表面改性 

分 类 号：TK02[动力工程及工程热物理]