Modification of a High-Temperature Electrochemical Testing Station and Experimental Development for Solid Oxide Electrolysis Cell Anode Analysis

Abstract

A method to fabricate solid oxide electrolysis cell (SOEC) anodes in a controlled process has been developed. Adjustment of deposition rate was found to alter the anode porosity and particle size distribution. A solid oxide fuel cell (SOFC) testing system was enhanced to complete steam electrolysis testing of the cells with prepared anodes. To prepare anodes of desirable morphology and uniform thickness the effect of spraying parameters on anode morphology were studied. Sonication of the anode inks was found to reduce particle agglomerations in the ink dispersion. A technique for obtaining and analyzing SEM cross sections of SOECs was developed to study prepared anodes. Investigation of sprayed anodes revealed that the porosity decreased as the deposition rate was increased. Using ImageJ analysis software particle size distributions of prepared anodes were determined. Anodes deposited at higher deposition rates were seen to have larger particle sizes. A greater anode deposition rate increased the likelihood of particle settling and agglomeration, leading to the decreased porosity and increased particle size in the anodes. A membrane humidifier was developed and tested to steadily supply steam to the electrolysis cell, the first such humidifier combined with a ProbotStatTM testing rig. Using the modified testing system, a testing method for SOEC analysis was developed. The process for producing polarization curves was studied to determine the desired testing conditions. During testing hysteresis between increasing and decreasing polarization curves, and anode conditioning during constant current electrolysis were seen for some cells. The appearance or absence of both phenomena were seen to be connected.