Effect of Chemically Etched Electrolyte on Solid Oxide Fuel Cell Performance

A chemical etching technique was used as a pretreatment of commercially available 8 mol % yittria stabilized zirconia (8YSZ) electrolyte to improve solid oxide fuel cell (SOFC) performance. It was found that the etching rate of the 8YSZ increased linearly with increases in hydrofluoric acid (HF) concentrations. Increasing the temperature of both a HF solution and a HF + HC1 (hydrochloric acid) solution accelerated the etching rate. Cell performance was improved not only by thinning the electrolyte but also by improved electrode performance, especially for the lanthanum strontium manganite (LSM) + YSZ composite cathode. An electrode kinetics analysis and scanning electron microscope (SEM) results suggest that this improved electrode performance was due to increases in three phase boundary (TPB) area.