Development of a Low-Cost, Durable Membrane and Membrane Electrode Assemby for Stationary and Mobile Fuel Cell Applications

Abstract

The development of low cost, durable membranes and membranes electrode assemblies (MEAs) remain a critical challenge for the successful introduction of fuel cells into mass markets. It was the goal of the team lead by Arkema, Inc. (formerly Atofina, Inc.) to address these shortages. Thus, this project addresses the following technical barriers from the Fuel Cells section of the Hydrogen Fuel Cells and Infrastructure Technologies Program Multi-Year Research, Development and Demonstration Plan: (A) Durability (B) Cost Arkema’s approach consisted in using blends of polyvinylidenefluoride (PVDF) and proprietary sulfonated polyelectrolytes. The strength and originality of Arkema’s approach lies in the decoupling of ion conductivity from the other requirements. Kynar® (Arkema trade name for PVDF) provides an exceptional combination of properties that make it ideally suited for a membrane matrix. In a first phase, Arkema demonstrated the feasibility of the concept with the M31 membrane generation. After MEA optimization, it was shown that the beginning-of-life (BOL) performance of M31 MEAs was essentially on a par with that of PFSA MEAs at 60oC under fully humidified conditions. On the other hand, long-term durability studies showed a high decay rate of 45µV/h over a 2100 hr. test. Arkema then designed several families of polyelectrolytemore » candidates, which – in principle – could not undergo the same failure mechanisms. A new membrane candidate was developed: M41. It offered the same generally good mechanical, ex-situ conductivity and gas barrier properties as M31. In addition, ex-situ accelerated testing suggested a several orders of magnitude improvement in chemical stability. M41 based MEAs showed comparable BOL performance with that of PFSA (80oC, 100% RH). M41 MEAs were further shown to be able to withstand several hours temperature excursions at 120oC without apparent damage. Accelerated studies were carried out using the DOE and/or US Fuel Cell Council protocols. M41 MEAs shown sizeable advantages over PFSA MEAs in the Open Circuit Voltage Hold test, Relative Humidity Cycling test and the Voltage Cycling test. The main known limitation of the M41 family is its ability to function well at low RH.« less