Fabrication and characterization of a PTFE-reinforced integral composite membrane for self-humidifying PEMFC

A novel PTFE-reinforced self-humidifying membrane based on low-cost sulfonated poly (ether ether ketone) (SPEEK) resin was fabricated. In the membrane a base layer and a thin protective layer were bonded by porous polytetrafluoroethylene (PTFE) film. The base layer, which is composed of silicon oxide supported platinum catalyst (abbreviated as Pt-SiO2) dispersed in SPEEK resin, can suppress reactant crossover and achieve good membrane hydration due to the imbedded hygroscopic Pt-SiO2 catalysts. The thin protective layer, which constitutes of H2O2 decomposition catalyst Pt-SiO2 and high H2O2-tolerant Nafion resin, aims to prevent the SPEEK resin degradation by H2O2 produced at the cathode side by incomplete reduction of oxygen. The porous PTFE film tightly bonds with the SPEEK and the Nafion resins to form an integral membrane and accordingly to avoid delamination of the two different resins. The self-humidifying membrane was characterized by TEM, SEM and EDS, etc. The self-humidifying membrane exhibits higher open circuit voltage (OCV) of 0.98 V and maximum power density value of 0.8 W cm−2 than 0.94 V, 0.33 W cm−2 of SPEEK/PTFE membrane under dry condition, respectively. The primary 250 h fuel cell durability experiment was conducted and suggested that this low-cost self-humidifying membrane was durable both on fuel cell performance and the membrane structure under fuel cell operation condition with dry H2/O2.