Nano-Ag particles for electrodes in a yttria-doped BaCeO₃ protonic conductor

Yttria-doped BaCeO₃ (BCY) has been studied as a proton conductor for use in vehicle fuel cells at moderate temperatures (773 to 873 K). The probe uses noble metals such as platinum (Pt) and/or palladium-silver (Pd-Ag) alloy for electrodes; but these metals are relatively expensive and must be fired with electrolytes at high temperatures. A solid fuel cell is needed that would function at temperatures from 573 to 673 K, the preferred temperature range for vehicles. An Ag electrode that fires at this middle range is being considered. A paste of nano-size Ag particles (NPS) was recently developed for electrical circuits. This research evaluates cell performance using these pastes. Results indicate that maximum power density of a fuel cell using a Pt anode and an Ag cathode (H₂, Pt|BCY20|Ag(NPS), Air) exceeded that of Pt|BCY20|Pt. Cells using NPS exhibited the highest density. When using Ag in both anode and cathode (Ag|BCY20|Ag), the maximum power density was consistently less than when using Pt alone. However, the maximum power density of the cell using NPS was closest to that achieved when using Pt in both electrodes.