介孔碳载体缓解碱性聚电解质燃料电池阳极水淹  

Alleviating anode flooding by mesoporous carbon supports for alkaline polymer electrolyte fuel cells

作　　者：江文涌 葛创新 王功伟 陆君涛[1] 肖丽[1,2] 庄林[1,3] Wenyong Jiang;Chuangxin Ge;Gongwei Wang;Juntao Lu;Li Xiao;Lin Zhuang(College of Chemistry and Molecular Sciences,Hubei Key Laboratory of Electrochemical Power Sources,Wuhan University,Wuhan 430072,Hubei,China;Sauvage Center for Molecular Sciences,Wuhan University,Wuhan 430072,Hubei,China;The Institute for Advanced Studies,Wuhan University,Wuhan 430072,Hubei,China)

机构地区：[1]武汉大学化学与分子科学学院,化学电源材料与技术湖北省重点实验室,湖北武汉430072 [2]武汉大学索维奇分子科学中心,湖北武汉430072 [3]武汉大学高等研究院,湖北武汉430072

出　　处：《Chinese Journal of Catalysis》2024年第2期51-58,共8页催化学报（英文）

基　　金：国家自然科学基金(21991154,21991150,22122204,21872108);武汉大学创新团队(2042022kf1174,2042022kf0029).

摘　　要：碱性聚电解质燃料电池(APEFCs)相较于目前研究最多的质子交换膜燃料电池(PEMFCs),其优势体现在阴/阳两极均可使用价格低廉的非贵金属催化剂,有望降低燃料电池的使用成本.APEFCs的研究在过去20年飞速发展,主要集中在高效碱性聚电解质(APE)隔膜和阴/阳极催化剂等关键材料的研发.目前,APEFCs的性能已接近于PEMFCs,针对其研究也逐渐从关键材料的研发扩展到电池的稳定性和水管理等更深层次问题.相较于PEMFCs,APEFCs的水管理问题更为复杂.每当阳极产生4个水分子,阴极会消耗2个水分子,容易导致阴极缺水和阳极水淹,进而影响电池的性能和稳定性.对APEFCs水管理的优化将是实现电池性能和稳定性突破的重要方向.本文主要研究碳载体对APEFCs水管理的影响,合成了一系列介孔碳负载的Ru催化剂(Ru/MCP-x,x为MCP的孔径,x=30,50,100 nm),并以Ru/XC72催化剂为对照.扫描电镜和N2吸附-脱附结果表明,介孔碳载体具有三维贯通的孔结构,而XC72为实心碳颗粒.溶液电化学测试结果表明,不同催化剂在0.1 mol/L的KOH溶液中的氢氧化反应(HOR)活性相当.以Ru/MCP-x和Ru/XC72为阳极催化剂进行电池装配(记为Ru/MCP-x电池和Ru/XC72电池),结果表明,当使用高进气流量(1000 mL/min)时,Ru/MCP-x电池和Ru/XC72电池性能接近;当使用更接近实际工况的低进气流量(200 mL/min)时,所有电池性能均有所下降,且降幅存在明显差距.其中,Ru/MCP-50电池和Ru/MCP-100电池的降幅分别为36%和35%,而Ru/MCP-30电池和Ru/XC72电池的降幅分别为43%和72%.通过在低进气流量下改变进气湿度,结果发现,Ru/MCP-30电池和Ru/XC72电池性能大幅下降的原因是阳极发生水淹.弛豫时间分布(DRT)方法可以将不同弛豫时间的极化过程在时域中分离开来,从而可以分辨各极化过程对电池性能的影响.利用电化学交流阻抗(EIS)技术结合DRT方法进一步分析各电池在不同电流密度下的阻�Water management is one of the critical issues affecting the performance and stability of alkaline polymer electrolyte fuel cells(APEFCs).This study focuses on the effect of carbon supports on the water management of APEFCs.A series of carbon-supported Ru catalysts(Ru/MCP-x)were prepared using mesoporous carbon powder(MCP-x)with three-dimensional through-nanopore structures as supports and compared with Ru/XC72.The results show that although the catalysts’hydrogen oxidation reaction(HOR)catalytic activities are similar in KOH solutions,the APEFCs performance can be severely different.APEFCs assembled with Ru/MCP-x and Ru/XC72(noted as Ru/MCP-x cell and Ru/XC72 cell)have little performance difference at high inlet H2 flow(1000 mL/min),but have a noticeable difference at low inlet H2 flow(200 mL/min).By combining the electrochemical AC impedance and distribution of relaxation time(DRT)method,we quantitatively identify that severe gas transfer resistance occurred in the anode catalyst layer of the Ru/XC72 cell under low inlet H2 flow,which is more in line with the actual APEFCs operating conditions,led to considerable degradation of the Ru/XC72 cell performance.The high gas transfer resistance is later ascribed to the anode flooding by combining the voltammetry curves and DRT plots.In contrast,for Ru/MCP-x cells,increasing the carbon supports'mesopore diameter dramatically reduced the gas transfer resistance and mitigated the anode flooding.This study shows a quantitative comparison of the impacts of different carbon supports on APEFCs performance and gas transfer resistance,indicating that mesoporous carbon materials have the potential to be supports for APEFCs anode catalysts to alleviate the anode flooding.

关 键 词：钌 介孔碳 碱性聚电解质燃料电池 水淹 弛豫时间分布 

分 类 号：TM911.4[电气工程—电力电子与电力传动]