Enhancement of oxygen reduction reaction kinetics using infiltrated yttria-stabilized zirconia interlayers at the electrolyte/electrode interfaces of solid oxide fuel cells

We fabricate intermediate-temperature solid oxide fuel cells (SOFCs) with infiltrated film-like yttria-stabilized zirconia (YSZ) interlayers at the electrolyte/electrode interfaces, achieving improved electrochemical performances. A thin and conformal nanocrystalline YSZ interlayer is deposited at the interface between the infiltrated La_0.8Sr_0.2MnO_3-δ nanoparticles and the YSZ scaffold using an infiltration process. The grain sizes of the infiltrated YSZ interlayers are controlled to be in the range of 8–40 nm with the sintering temperature for the infiltrated YSZ interlayer in the range of 800–1200 °C. The infiltrated YSZ interlayer provides 3.18 times reduced polarization resistance and 2.08 times increased maximum power density of 0.1 Ωcm² and 1.54 Wcm⁻² at 750 °C compared to those of an untreated cell, respectively. The substantially improved oxygen reduction reactions are attributable to the increased grain boundary densities in the infiltrated YSZ interlayer, which provide an increased number of reaction sites with a relatively low reaction barrier. Our results demonstrate that modifying the microstructures of the SOFC components at the electrolyte/electrode interfaces using conventional materials can improve electrode performances.