Durability test of PEMFC with Pt-PFSA composite membrane

摘要

Self-humidifying proton exchange membrane fuel cell (PEMFC) has aroused quite many interests because this kind of fuel cell system is so simple that only air blower is needed to supply reacting and cooling air. Composite membrane with Pt particles embedded in perfluorosulfonate acid (Pt-PFSA) resin exhibits good self-humidifying fuel cell performance, while the inorganic Pt particles destroy the integrality of the organic PFSA membrane and the durability of this kind of membrane is questionable. In this paper, Pt-PFSA composite membrane was prepared and the durability of the membrane in midterm fuel cell operation was tested and compared with PFSA membrane. Two single cells with 25 cm~2 active area were assembled with Pt-PFSA membrane and PFSA membrane, and continuously operated at constant current density of 500 mA/cm~2, 50 ℃, with dry H_2 and dry air for 1000 h. Polarization curves, cyclic voltammetry and AC impedance analysis were conducted during the durability test. The results reveal that the Pt-PFSA cell shows better stability in fuel cell performance than the PFSA cell, while the hydrogen crossover current density increases about 100 times, which indicates much faster corrosion speed of the Pt-PFSA membrane than the PFSA membrane during the mid-term continuous fuel cell operation. The experimental results illustrate that much more efforts are needed to be focused on the integrity and degradation prevention of the Pt-PFSA membrane, although it shows excellent mid-term self-humidifying performance.