PEMFC fuel cells: Improvements and Difficulties (Part-2)
With an eye to their use in transportation, much work needs to be done to enhance membranes' functionality as well as their chemical and mechanical durability. Proton conductivity is improved by new research that focuses on lowering membrane swelling while assuring excellent water retention at high temperatures. The control of the charges' dispersion within the organic matrix, with which the charges interact little, is still a challenge for these new membranes. The goal is to guarantee their percolation while preventing their elution in the presence of water.
Interpenetrating polymer networks as fuel cell membranes:
The idea is to link together two polymer networks that are intertwined but autonomous. The two networks' interconnectedness guarantees superb mechanical and chemical stability, the membrane's chemical and mechanical safety are provided by the first, which is fluorinated, while the second encourages proton transmission.
How should active layers and catalysts be set up?
At the level of the active layers, the location of the electrochemical processes crucial to generating the power needed by the system, is a key zone. Catalytic materials are used to create these active layers, which are positioned on either side of the proton exchange membrane. Rapid corrosion of the materials is caused by the membrane's close closeness, which enforces extremely acidic working conditions, electrodes must then be made of elements that remain solid in an acidic environment. Transition metals are not acceptable as electrical reaction catalysts because of this prerequisite, the only metal with adequate catalyst potential is platinum, but it is a costly one. Fuel cells cost fifty percent more today just for platinum.
References:
Les matériaux au cœur du processus d'innovation- Clefs CEA No 59 – Publication: Summer 2010.
Maiyalagan T, Pasupathi S. Components for PEM Fuel Cells: An Overview. MSF 2010;657:143–89.