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Posted on April 16, 2024 by  & 

Membrane Materials for PEM Fuel Cells in the Post-PFAS World

PFAS - Per- and poly-fluoroalkyl substances - 3D molecule conformer. 3D Illustration
Membrane materials are of fundamental importance for fuel cells, even giving their name to the specific type of fuel cell, as is the case for Proton Exchange Membrane (PEM) fuel cells. Typically, these membranes consist of ionomers containing perfluoroalkyl substances (PFAS), which in turn are subject to increasing concern and proposed regulations. In response to this, alternative materials for membranes are beginning to emerge.
The IDTechEx report on the topic, "Materials for PEM Fuel Cells 2024-2034: Technologies, Markets, Players", gives a detailed technical overview of membranes and other key components for PEM fuel cells and predicts the beginning of a transition away from PFAS membranes to alternatives within the next three to five years. The report also assesses the major players and provides granular 10-year market forecasts for key fuel cell components and materials in terms of both units and volume.
PEMs carry out a key role in the fuel cell; transporting protons across the cell while keeping the two fuels (oxygen and hydrogen) separated. The IDTechEx report extensively benchmarks the market leader against competing ionomer materials for three of the most crucial parameters for PEMs: electrical resistance, ion exchange capacity (IEC), and membrane thickness.
Although the membrane must be ionically conductive with respect to transporting protons, it is of crucial importance that the material is electrically insulating to avoid short-circuiting the cell. Rapid proton transport across the cell is enabled by a combination of high IEC and a thin membrane structure. Promising alternatives to PFAS-containing membranes exist; however, these are at an early stage, with no clear forerunner in the race to replace PFAS.
Proposed PFAS regulations will necessitate the development of alternative membrane materials for PEM fuel cells. Some of the promising options include hydrocarbons and MOF membranes, but which material parameters are key for success? Source: IDTechEx
In terms of emerging alternative materials, the question of which material parameters are of key importance must be addressed. The membrane is subject to oxidizing and reducing environments on either side of the cell and so must be able to exist in harsh, opposing conditions. The mechanical strength of the membrane directly impacts the performance of the fuel cell. A material with a higher strength can be manufactured to be thinner, leading to a higher power density for the fuel cell stack. Reinforcement can be added to the membrane by manufacturing a composite material. It is imperative that the membrane is impermeable to all but the protons that are exchanged from one side of the fuel cell to the other. Gas crossover occurs if either gas passes through the membrane, while the fuel cell would be short-circuited if the membrane is electrically conductive and allows electrons to pass through. Finally, as for all material supply, it is important that the membrane material can be produced easily and at a low cost.
So, which materials are at the fore of replacing PFAS in PEM fuel cells? Prototype developmental projects are underway with various OEMs, and novel materials are gaining traction, predominantly at an academic level. IDTechEx provides an assessment of composite membranes containing metal-organic frameworks (MOFs), benchmarking various materials across a number of parameters. Historically, hydrocarbons have not seen success as membrane materials due to their tendency to disintegrate in the harsh chemical environments within the fuel cell. However, recent advances have seen the development of hydrocarbon ion-exchange membranes capable of fulfilling the requirements for PEM fuel cells. Ultimately, IDTechEx expects to see the beginning of a transition away from PFAS membranes to alternatives (led by hydrocarbons) within the next three to five years.
Beyond fuel cells, increased restrictions on PFAS driving development of alternative materials in various other emerging technologies. IDTechEx has released a new report, "Per- and Polyfluoroalkyl Substances (PFAS) 2024: Emerging Applications, Alternatives, Regulations", providing an assessment of emerging PFAS alternatives in critical application areas such as the hydrogen economy, 5G, electric vehicles, and sustainable packaging. Also included is an extensive analysis of current and proposed regulations limiting the use of PFAS.
For more details on the materials demand, trends, and emerging novel alternatives to the incumbents for PEM fuel cells, see the IDTechEx market report "Materials for PEM Fuel Cells 2024-2034: Technologies, Markets, Players".
For more information on this report, including downloadable sample pages, please visit
For the full portfolio of market research from IDTechEx, please visit
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Authored By:

Senior Technology Analyst

Posted on: April 16, 2024

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