Diagnosis of PTFE-Nafion MEA degradation modes by an accelerated degradation technique

Abstract

SUMMARYCost and durability are central issues in the commercialization of proton-exchange membrane fuel cells. This study used complex accelerated-degradation protocols to diagnose the degradation modes of low-cost polytetrafluoroethylene-Nafion membrane electrode assemblies (MEAs). Acceleration protocols included open-circuit voltage, relative humidity cycling, and load cycling. Failure modes included measurements of cyclic voltammetry, linear sweep voltammetry, polarization curve, and AC impedance. The four modes (stages) of degradation were determined to be (i) catalyst aging, (ii) creep deformation, (iii) pinhole formation, and (iv) membrane failure. During catalyst aging, the maximum power density decreased by 0.117 mW cm À2 cycle À1 . After the 280th cycle, creep deformation occurred, and the maximum power density decreased by 0.227 mW cm À2 cycle À1. Pinholes led to membrane failure and a final dramatic loss of performance (À0.453 mW cm À2 cycle À1 ). Therefore, membrane failure is the major factor in the failure of MEAs.

Multi-objective optimization of a direct methanol fuel cell system using a genetic-based algorithm

“…The thickness of the Nafion 117 membrane (MEA type A) is taken as 175 mm with a bulk conductivity of 0.1 S/cm [6,13,15].…”

Performance of CCM ‐type MEAs based on a CsH 5 ( PO 4 ) 2 ‐doped Polybenzimidazole membrane for HT‐PEMFC

“…Membrane electrode assembly (MEA) is the most vital component for both HT‐PEMFC and LT‐PEMFC and is composed of a proton exchange membrane (PEM), two gas diffusion layers (GDLs), and two catalyst layers (CLs) for the cathode and anode 9‐11 . The electrochemical reactions of the MEA occur at the three‐phase boundaries in both cathode and anode, where the catalyst particles, electrolyte, and reactant gases come into contact 12 . The methods for MEA preparation are mainly the catalyst‐coated membrane (CCM) method 13 and the catalyst‐coated substrate (CCS) method 14,15 .…”

“…[9][10][11] The electrochemical reactions of the MEA occur at the three-phase boundaries in both cathode and anode, where the catalyst particles, electrolyte, and reactant gases come into contact. 12 The methods for MEA preparation are mainly the catalystcoated membrane (CCM) method 13 and the catalystcoated substrate (CCS) method. 14,15 For the MEAs prepared by the CCS method, the interface between the CL and the electrolyte membrane is not in close contact, thus giving high interface resistance and resulting in a relatively low output power density of the fuel cell.…”

Experimental study and mitigation of abnormal behavior of cell voltage in a proton exchange membrane fuel cell stack

“…Proton exchange membrane fuel cells (PEMFCs) with its high efficiency, negligible emissions, low noise, and simple in design are used more and more widely. But durability and reliability are key issues that need to be addressed before mass commercialization. Fuel cell design and assembly, material degradation, operating conditions, and impurities or contaminants can affect the durability and reliability of PEMFCs .…”