Direct membrane fuel cells performance degradation

Franco AA (2012) PEMFC degradation modeling and analysis. In Hartnig C, Roth C (eds) Polymer electrolyte membrane and direct methanol fuel cell technology (PEMFCs and DMFCs). Volume 1 Fundamentals and performance. Woodhead, Cambridge, UK... 

Water management is very delicate for fuel cell users to control. Too much or too little water can degrade both the performance and therefore the lifetime of PEM fuel cells. If the membrane is too dry, it results in a direct decrease of membrane conductivity. If water is not removed adequately from the cell, especially at the cathode, liquid water flooding occurs, which leads to PEM fuel cell performance that is unpredictable, unreliable, and unrepeatable under identical operating conditions. Therefore, maintaining a perfect water balance during dynamic operation processes is crucial to fuel cell performance and lifetime [41]. 

As electrochemical reaction sites, CLs play an extremely important rote in the performance of fuel cell stacks. A CL mainly consists of catalyst, support and binder. The CL is usually coated on the surface of the GDL. Another method has the CL directly applied to the membrane (catalyst coated membrane, CCM). The selection of the components, the proper ratios of those components, the structure of the formed CL and the formation method of the CL are critical factors in the performance of a fuel cell. The stability of the fuel cell performance is directly related to the stabilities of the catalyst, binder and support in flie CL. Degradation of catalytic activity would be due to the agglomeration of the eatalyst particles and their detachment from the support, the degradation of the binder, and the oxidation and corrosion of the support, particularly at the cathode. Further improvement in CL performance is possible. The basic technical considerations include how to maximize the three-phase interface of the CL, how to stabilize the metal particles on the support, and how to reduce the degradation of the components in the CL. 

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