Millet P., Grigoriev S., 2014, Electrochemical Characterization and Optimization of a PEM Water Electrolysis Stack for Hydrogen Generation, Chemical Engineering Transactions, 41, 7-12.
Polymer Electrolyte Membrane (PEM) water electrolysis is considered as a key process for the conversion of zero-carbon electricity into zero-carbon hydrogen in view of different end-uses (in the chemical industry sector but also for energy storage and transport applications). In conventional systems, PEM water electrolysis cell are usually operating at 1.8 V and 1 A.cm-2 (˜ 80% efficiency). Low pressure electrolysers (1-50 bars) that can deliver several tens of Nm3 H2 / hour are appearing on the market. The technology is well-suited for operation using intermittent and fluctuating power sources but still suffers from an elevated cost. Operation at higher current densities could help to bring cost down to market requirements but innovative cell design are needed. The purpose of this communication is to provide some insight on the electrochemical characterization and optimization of PEM water electrolysis stacks. A simple hydrodynamic model has been used to optimize the internal geometry of the PEM cells (selection of cell components, internal design, geometry) from an engineering viewpoint. Cyclic voltammetry measurements have been made to identify the origin of performance limitations and to evaluate the homogeneity of the electrical environment experienced by individual membrane-electrode assemblies during operation. Some issues related to the development of next generation PEM electrolysers equipped with simplified cell structures and operating at higher current densities (in the multi Amp per cm2 range) in view of future market applications are discussed.
