Nanostructured and Self-Assembled Superhydrophilic Bipolar Plate Coatings for Fuel Cell Water Management
G. Dadheech, M. Abd Elhamid, R. Blunk
General Motors Corporation, US
Keywords: hydrophilic, bipolar plate, fuel cells, water management
Abstract:A stably superhydrophilic coating is required on composite and metal bipolar plates to manage byproduct liquid water and, in turn, to enable good PEM fuel cell performace under low power vehicle operating conditions. Silica-based coatings, particularly those derived from particulate sols and applied using a self-assembly layer-by-layer (LbL) process, can be rendered superhydrophilic by tailoring its nanostructure. These nanoparticle coatings can also meet other bipolar plate requirements such as low electrical contact resistance, high electrochemical stability, good wet adhesion and low cost. However, itís questionable whether these desired coating properties can be maintained over a 10-year stack life as three modes of hydrophilicity loss--dissolution, adhesion, and contamination--are observed. New nanostructured coating materials and processing developments are needed to mitigate these loss mechanisms, particularly the latter.