Screening Balance of Plant Materials to Understand their effect on Fuel Cell Performance

Extensive research on fuel cell stack materials has led to advances in lower cost, high performing materials. With the decrease in the cost of stack materials, lowering the cost of the balance of plant (BOP) components has increased in importance. In order to decrease the overall cost of the automotive and stationary fuel cell systems and make them as competitive as possible, low-cost system component materials that provide similar function, performance and durability are needed. However, intelligently selecting low cost materials for application in polymer electrolyte membrane fuel cell (PEMFC) systems requires understanding the potential adverse effects that system contaminants may have on the fuel cell performance and durability. Limited work in this area has been conducted to-date [1-16]. There are many prospective BOP materials that can be used in fuel cell systems. Our material selection was based on the material’s physical properties (i.e., whether it will be stable in fuel cell operating conditions), commercial availability, cost and input from OEMs and fuel cell system manufacturers [1,2,5]. The prioritization of the materials to be studied was based on wetted surface area, total mass-to-volume ratio, proximity to MEAs, function, cost, and performance implications. Families of material chosen for the study include structural materials, elastomers for seals and (sub)gaskets, and assembly aids (adhesives, lubricants). Furthermore, different grades of BOP materials, containing different polymer resin grades and additives from different manufacturers were selected for this study. The contaminants can come from the parent polymer material or the additives that were added to provide specific physical properties, such as glass fiber for structural reinforcement. Hence, it is important to determine what species leached out of the BOP materials, where the contaminating species come from, their impact on fuel cell performance, and whether the contaminating species can be removed or substituted via communication with the supplier manufacturer. These results would help the fuel cell industry in selecting appropriate BOP material for fuel cell applications. To quantify the impact of system contaminants on fuel cell performance, many prospective fuel cell system relevant BOP materials were screened, using a suite of exsitu and in-situ techniques [1,2,6-16]. The materials were aged in DI water at 90oC for 6 weeks. The liquid phase, extractions were analytically characterized by gas chromatography-mass spectrometry (GCMS), total organic carbon (TOC), inductively coupled plasma (ICP), solution conductivity, and ion chromatography (IC) to identify and quantify the species that leached out of the BOP materials. Their effect on catalyst performance and membrane conductivity were studied ex-situ and compared with the in-situ fuel cell results. This talk will give a general overview of the screening results for the assembly aids materials as well as focus on the catalytic effect of selected assembly aids materials.