Water and ion transport in ceramic carbon electrodes for fuel cells

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Polymer electrolyte membrane fuel cells (PEMFC) are a clean energy technology that electrochemically reacts hydrogen and oxygen to produce water and electricity. PEMFCs are currently becoming profitable in niche commercial markets such as industrial vehicles (e.g. forklifts), and stationary/backup power. The technology could be more widely deployed in the energy landscape provided that improvements can be made in the performance-to-cost ratio of the materials. This proposal is focused on the study and enhancement of a new and innovative fuel cell electrode technology, namely sulfonated silica-based ceramic carbon electrodes (SS-CCE). SS-CCE's are prepared using low-cost organosilane precursors that are mixed with the platinized carbon (Pt/C) catalyst in monomer form, and subsequently polymerized and coated onto a gas diffusion layer in a single step. These electrode structures display excellent performance and superior tolerance to dry operating conditions compared to conventional fuel cell materials, whose performance suffers severely if not well hydrated. The ability to operate hot/dry could leave means less parasitic power is consumed by humidifier systems which would lead to substantial system efficiency. The long term objective of this strategic grant is aimed at understanding the phenomena that enable these SS-CCEs to perform well under dry conditions, and to further improve the material's performance. This will in turn allow evaluation of our new strategy for water retention under hot and dry operating conditions - locating hygroscopic additives in each catalyst layer, as opposed to the conventional approach of modifying the membrane with similar hygroscopic materials. This project will focus on understanding how the chemical composition influences the electrochemical and physical properties of the electrodes. This, along with real world testing durability measurements of fuel cells made from SS-CCEs will enable the evaluation of our novel approach to high temperature/low relative humidity fuel cell operation. It is expected that the results from this project will lead to the development of higher-performing and lower-cost fuel cells, which will enable Canada to meet its clean energy needs.