摘要
采用开路电压(OCV)工况研究了质子交换膜燃料电池(PEMFC)膜电极的耐久性,在OCV工况运行过程中,定期地通过极化曲线、电化学交流阻抗谱(EIS)、线性扫描伏安法(LSV)、短路电阻测试等在线测试方法对膜电极性能进行分析。当OCV工况运行结束后,采用扫描电镜(SEM)、离子色谱对质子交换膜(PEM)厚度和阴、阳极废水进行分析。结果表明,在OCV工况下运行115h后,PEMFC的开路电压由1.013V下降到0.794V,最大功率密度由538.8mW/cm^2下降到196mW/cm^2;在线电化学测试结果表明,欧姆电阻先减小后增大,氢气渗透通量逐渐增大,短路电阻逐渐减小;离子色谱测试结果表明,阴极和阳极废水中都存在氟离子;SEM表征发现,PEM厚度减小;在OCV工况下,PEM发生了衰减,从而导致PEMFC开路电压下降和性能衰减。研究结果表明PEM是影响膜电极耐久性的重要因素。
Proton exchange membrane fuel cell(PEMFC)is environmentally friendly energy producer.It is one of the leading clean energy technologies being considered for transportation applications and power generation.The main hurdle limiting the large scale commercialization of PEMFC is the durability.In this paper,durability of membrane electrode assembly for fuel cell was investigated under open circuit voltage(OCV)operation at 90℃,30%RH(relative humidity)and 50 kPa backpressure.A single cell with an active area of 25 cm 2 was tested.The membrane electrode assembly consists of Nafion 212 proton exchange membrane(PEM),catalyst layer and gas diffusion layer.The performance of PEMFC during the OCV operation was characterized with the help of in situ electrochemical measurements,such as polarization curves,electrochemical impedance spectroscopy(EIS)and linear sweep voltage scans(LSV).Postmortem analyses such as scanning electron microscopy(SEM),and ion chromatography were applied to identify the membrane electrode assembly degradation mechanisms during the OCV operation.The open circuit voltage degradation include reversible degradation and irreversible degradation.The open circuit voltage declined from 1.013 V to 0.794 V,and the maximum power density declined from 538.8 mV/cm 2 to 196 mW/cm 2 after 115 h of OCV operation.The on-line electrochemical measurements show that the ohmic resistance increased at the beginning and then decreased along with the OCV operation duration,while the hydrogen crossover continued to increase during the whole OCV operation.At the beginning of OCV operation,the hydrogen crossover current density was 0.867 mA/cm 2.However,hydrogen crossover current density became 12.64 mA/cm 2 after 96 h of OCV operation.Ion chromatography and SEM results showed that fluoride ions existed in both the anode and cathode effluent waterand the PEM became thinner after OCV operation.The results indicate that structural changes in PEM are the main reasons of PEMFC performance decline during OCV operation.This study
作者
黄豪
杨座国
王亚蒙
胡鸣若
倪蕾蕾
曾乐才
季文姣
HUANG Hao;YANG Zuo-guo;WANG Ya-meng;HU Ming-ruo;NI Lei-lei;ZENG Le-cai;JI Wen-jiao(School of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China;Central Academy,Shanghai Electric Group Co.Ltd,Shanghai 200070,China;Institute of Fuel Cell,Shanghai Jiao Tong University,Shanghai 200240,China)
出处
《华东理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2018年第5期638-643,共6页
Journal of East China University of Science and Technology
