(Invited) Addressing Durability in Long-Life, Low-Power Fuel Cells

Abstract

Fuel Cells’ scalability and energy density make them excellent candidates for different applications, especially difficult to electrify applications. Their design flexibility can also be applied to low power, long-life applications. LANL has constructed a unique design to provide continuous, low power (< 100 µW) for very long duration (multiple decades). This LANL system operates passively, without active control of cell parameters, such as temperature and humidity. In addition, the system does not require interventions like refueling or maintenance during its operational lifetime. While the application and operational conditions of the systems mentioned here differ greatly from those of light and heavy-duty vehicles (e.g. ambient temperature operation, passive water management, low current densities), many of the modes of degradation are similar, and listed below: Membrane thinningDegraded performance due to loss of electrochemical surface area (ECSA)Loss of water management due to changes in hydrophobicityIncreased cell resistance due to corrosion of cell components To better understand these degradation processes LANL has performed accelerated stress tests (ASTs) to induce and quantify the membrane thinning, loss of ECSA, hydrophobicity, and bipolar plate corrosion. Those ASTs include long term OCV holds with reactants present, high potential cycling (1-1.5 V) in flooded conditions, potential cycling to induce catalyst Ostwald ripening, and exposure of cell components to corrosive environments.