U.S. DOE Progress Towards Developing Low-Cost, High Performance, Durable Polymer Electrolyte Membranes for Fuel Cell Applications

Abstract

Low cost, durable, and selective membranes with high ionic conductivity are a priority need for wide-spread adoption of polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs). Electrolyte membranes are a major cost component of PEMFC stacks at low production volumes. PEMFC membranes also impose limitations on fuel cell system operating conditions that add system complexity and cost. Reactant gas and fuel permeation through the membrane leads to decreased fuel cell performance, loss of efficiency, and reduced durability in both PEMFCs and DMFCs. To address these challenges, the U.S. Department of Energy (DOE) Fuel Cell Technologies Program, in the Office of Energy Efficiency and Renewable Energy, supports research and development aimed at improving ion exchange membranes for fuel cells. For PEMFCs, efforts are primarily focused on developing materials for higher temperature operation (up to 120 °C) in automotive applications. For DMFCs, efforts are focused on developing membranes with reduced methanol permeability. In this paper, the recently revised DOE membrane targets, strategies, and highlights of DOE-funded projects to develop new, inexpensive membranes that have good performance in hot and dry conditions (PEMFC) and that reduce methanol crossover (DMFC) will be discussed.

Key Factors Affecting the Performance and Durability of Cathode Electrocatalysts in Polymer Electrolyte Fuel Cells Characterized by In Situ Real Time and Spatially Resolved XAFS Techniques

“…To solve these problems, in situ/operando techniques, which can directly characterize cathode electrocatalysts in membrane electrode assembly (MEA) of PEFC, validate catalyst fabrications, and prove fundamental issues for development of next-generation PEFCs, are mandatory. Particularly, it is necessary to elucidate key factors affecting the performance and durability of cathode electrocatalysts in PEFCs though lots of studies have been devoted to these essential problems [1,2].…”

Contribution of Electrocatalyst Support to PEM Oxidative Degradation in an Operating PEFC

“…25 μm, or even lower thickness variants). 4,10,11 However, the long-term durability of PEFC components still remains a major concern. The key issues affecting PEFC durability include electrode degradation via carbon corrosion, 1,[12][13][14][15] Pt dissolution, 5,[16][17][18][19] catalyst sintering 20,21 and electrolyte degradation via PEM oxidative degradation.…”

“…2,4 The high cost of component materials, such as platinum (Pt) electrocatalyst 5,6 and Nafion electrolyte membranes are among the main factors influencing the cost of PEFCs.…”

“…[1][2][3] The commercialization of PEFCs, particularly for the automobile sector, has been hindered by high cost and insufficient component durability. 2,4 The high cost of component materials, such as platinum (Pt) electrocatalyst 5,6 and Nafion electrolyte membranes are among the main factors influencing the cost of PEFCs. 4,[7][8][9] Recent advances in the design of PEFCs enable high performance with very low total Pt loadings (ca.…”

“…[50][51][52][53][54][55][56][57] These ROS initiate and sustain the chemical degradation of the PEM (via oxidative attack of the polymer chains by ROS). 1,3,4,11,[58][59][60][61][62][63][64] PEM degradation is an autocatalytic reaction with a large induction time, with the ultimate consequence being catastrophic cell and stack failure. The carbon-based support is therefore one of the contributors to PEM degradation.…”