Proton Exchange Membranes for Fuel Cells
Proton exchange membrane, also known as polymer electrolyte membrane, fuel cells (PEMFCs) offer the promise of efficient conversion of chemical energy of fuel, such as hydrogen or methanol, into electricity with minimal pollution. Their widespread use to power zero-emission automobiles as part of a hydrogen economy can contribute to enhanced energy security and reduction in greenhouse gas emissions. However, the commercial viability of PEMFC technology is hindered by high cost associated with the membrane electrode assembly (MEA) and poor membrane durability under prolonged operation at elevated temperature. Membranes for automotive fuel cell applications need to perform well over a period comparable to the life of an automotive engine and under heavy load cycling including start-stop cycling under sub-freezing conditions. The combination of elevated temperature, changes in humidity levels, physical stresses and harsh chemical environment contribute to membrane degradation. Perfluorinated sulfonic acid (PFSA)-based membranes, such as Nafion®, have been the mainstay of PEMFC technology. Their limitations, in terms of cost and poor conductivity at low hydration, have led to continuing research into membranes that have good proton conductivity at elevated temperatures above 120 °C and under low humidity conditions. Such membranes have the potential to avoid catalyst poisoning, simplify fuel cell design and reduce the cost of fuel cells. Hydrocarbon-based membranes are being developed as alternatives to PFSA membranes, but concerns about chemical and mechanical stability and durability remain. Novel anhydrous membranes based on polymer gels infused with protic ionic liquids have also been recently proposed, but considerable fundamental research is needed to understand proton transport in novel membranes and evaluate durability under fuel cell operating conditions. In order to advance this promising technology, it is essential to rationally design the next generation of PEMs based on an understanding of chemistry, membrane morphology and proton transport obtained from experiment, theory and computer simulation.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1000630
- Report Number(s):
- PNNL-SA-68801; KC0302020; TRN: US201101%%427
- Resource Relation:
- Related Information: Energy Production and Storage - Inorganic Chemical Strategies for a Warming World, 89-100
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
10 SYNTHETIC FUELS
30 DIRECT ENERGY CONVERSION
AUTOMOTIVE FUELS
CHEMISTRY
COMPUTERIZED SIMULATION
ENGINES
FUEL CELLS
GREENHOUSE GASES
HUMIDITY
HYDRATION
HYDROGEN
MEMBRANES
METHANOL
MORPHOLOGY
POLLUTION
POLYMERS
PROTON TRANSPORT
PROTONS
SULFONIC ACIDS
VIABILITY
proton exchange membranes
fuel cells
Nafion
hydrocarbon membrane
ionic liquid