Incentives for developing high temperature electrolysers (HTEs) using proton conducting electrolytes stem from the fact that a proton ceramic electrolysis cell (PCE) pumps out and pressurises dry H2 directly. Existing HTEs design utilises the high packing density of planar stacks, but the hot seal and vulnerability to single cell breakdown give high stack rejection rate and questionable durability. Recently, we demonstrated an innovative PCE technology utilising tubular proton conducting ceramic cells and their inherent advantages: lower operating temperature than traditional solid oxide ion conducting electrolysis cells; increased safety as the pressurized hydrogen is balanced by a mixture of steam and oxygen; reduced sealing areas and increased robustness in particular, when exposed to pressure differentials, compared to planar stacks. The tubular cells consist of a porous Ni- BaZr0.7Ce0.2Y0.1O3- δ (BZCY) cathode for the H2 side, a dense BZCY-based electrolyte, and a porous Ba1-xGd0.8La0.2+xCo2O6-δ (BGLC)-BZCY composite anode for the H2O+O2 side. Extensive characterisation of the cells' performance as function of temperature, pressure (up to 10 bar) and steam content has been carried out showing positive impact of pressure and steam on the Faradaic efficiency and hydrogen production rate of the cells, as will be reported here. Further to this work, we extended the use of proton ceramic-based cells to other applications: ammonia cracking, dehydrogenation of hydrocarbons, and reversible steam electrolysis. The cells' architectures are tailored for each application by modifying the anode composition and microstructure. This work is guided by systematic experimental work on modelled electrodes and parameterization of cell's performance as function of operating conditions. The experimental work is steered by multi-scale multi-physics modelling establishing correlations and functions between atomistic, electrode, cell, reactor and system levels. The resulting technology platform based on electrochemical proton conducting ceramic cells is shown to provide new paths towards the viable production, extraction, purification and compression of hydrogen. In this presentation, we will provide information on cell's production and characterization, electrochemical testing at tubular cell level including durability test extending to more than 3000 hours, impact on process conditions on cell's performance, and insights into the multi physics multi scale (kinetics, electrochemical, mechanical, engineering) models established for the selected applications.
This presentation is given on behalf of the WINNER consortium. The project has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking (now Clean Hydrogen Partnership) under Grant Agreement No 101007165. This Joint Undertaking receives support from the European Union’s Horizon 2020 Research and Innovation program, Hydrogen Europe and Hydrogen Europe Research.