Transport phenomena in fuel cells

点击翻译按钮获取中文摘要

Polymer Electrolyte Membrane Fuel Cells (PEMFCs) are electrochemical energy conversion devices that can provide clean power to road vehicles, homes and portable electronics. The operation and durability of a fuel cell depend on the regulation of several transport processes: the flow of reactant gases, product water, heat, electrons and protons in conjunction with reaction kinetics. These processes take place in a variety of materials and components having characteristic features ranging from nanometers to centimeters. Further progress in this relatively young and evolving technology is limited by transport phenomena issues at the boundaries of current knowledge. Information on the morphological structure and transport parameters of the porous electrode layers is scarce. Liquid water is often present in PEMFCs, and while this helps maintain hydration of the polymer membrane, it also leads to flooding; the mechanisms of liquid water formation and transport are not well understood. Due to the multi-layered architecture of fuel cells, significant losses can occur at interfaces; the interfacial phenomena need to be characterized and quantified. The in-situ environment in a PEMFC makes experimental observations extremely challenging. We proposes new experimental and computational methods to: a) resolve the nano-structure and transport phenomena in composite catalyst layers by using a combination of advanced microscopy, reconstruction techniques and pore scale modelling; b) measure and predict the effective conductivities of porous electrodes; c) improve understanding of the challenging issue of water transport through visualization and dynamic simulations; d) integrate state-of-the art component models in a multi-scale computational framework; and e) validate and apply the model to explore novel concepts and strategies to improve transport processes.