Thin layer electrolyte impregnation into porous anode-supported fuel cell by ultrasonic spray pyrolysis

An ultrasonic spray pyrolyzed thin layer electrolyte impregnates into a porous anode and extends the depth of triple phase boundaries (TPBs) to several times that of the dense thin-layer thickness. This process, without an anode functional layer, improves the conventional repeated impregnation that results in anode porosity blocking and difficult extending to the anode/electrolyte interface. A (La_0.75Sr_0.2Ba_0.05)_0.175Ce_0.825O_1.981 (LSBC) electrolyte thin layer (iLSBC) is deposited on a porous La_0.3Sr_0.7TiO₃ (LST) anode by ultrasonic spray pyrolysis using 0.1 M LSBC precursor at a substrate temperature of 450 °C, while controlling the solution flow rate and spray volume. The spray pyrolyzed iLSBC/LST half-cells co-fired at 1350 °C/6 h exhibit no evident second phase in the X-ray diffraction analysis. The depth profile of iLSBC/LST indicates an approximately 2.75 μm-thick layer with the Ce element line scanning showing a significantly higher impregnation depth. Slight lattice distortion among the impregnated region may be due to the iLSBC diffusion, resulting in the extension of the TPB area and length. The half-cell reaches a low impedance and achieves a power density of 377 mW/cm² at 750 °C.