摘要
本文考察了阴极侧添加不同含量PTFE封质子交换膜燃料电池（PEMFC）膜电极（MEA）结构及性能的影响。分别采用扫描电镜（SEM）、循环伏安（CV）和电化学交流阻抗谱（EIS）技衡对PEMFC的微观结构、电化学性能进行了表征。通过电池的放电曲线发现PTFE的添加对电池的性能有很大影响：当阴极催化剂中PTFE的含量≤10％时，燃料电池的性能随PTFE含量的增加而提高；但进一步提高PTFE的含量，电池性能反而下降。SEM、CV及EIS结果表明，适量PTFE的添加增加了催化剂的分散度并有助于催化剂之间的孔隙形成网状结构，从而提高了电化学反应的活性面积，并促进电荷传递及氧气、水的傅质过程。但过量的PTFE可能会导致形成无孔膜，使得傅质阻抗以及电荷傅递阻抗变大，导致电池性能降低。
The effect of the PTFE （polytet rafluoroethylene） content in the cathode catalyst layer on the MEA structure and the performance of the single proton exchange membrane fuel cells （PEMFCs） were studied. SEM technique was used to characterize the microstructure of PEMFC. Electrochemical impedance spectroscopy （EIS） and cyclic voltammetry （CV） were used to on-line characteristic the performance of the PEMFCs with different PTFE contents at cathode catalyst layers. It was found that the addition of PTFE affects the performance of fuel cell significantly based on the discharge characteristics. The fuel cell performance is remarkably improved with the increase in the PTFE content at the cathode catalyst layer up to 10%. However, it decreases with further increase of the PTFE content.It has been proven that addition of suitable amount of PTFE improves the dispersion of catalyst and forms worm-like pores, which favors for the higher utilization of catalysts and increases the active surface area for electro-chemical reaction. The most important role of PTFE is the mass-transfer ability of oxygen and water transportation can be improved by decreasing the mass transfer resistance. So the rate-determining kinetic oxygen reduction process can be enhanced. While, excessive PTFE may increase the resistance of fuel cell increased and consequently lowers the fuel cell performance.
基金
本课题得到高等学校博士学科点专项科研基金（新教师基金）（项目编号：20070247055）
国家自然科学基金（项目编号：20703031）
同济大学青年优秀人才培养行动计划（项目编号：1700279016）
上海市分子催化和功能材料重点实验室开放基金（项目编号：2005KF06）资助.
