Precision surface modification of solid oxide fuel cells via layer-by-layer surface sol–gel deposition

While solid oxide fuel cells (SOFCs) are a promising technology for a clean and sustainable future, their commercialization is hindered by limited durability and performance. Here, we report our findings on the application of a layer-by-layer surface sol–gel (SSG) coating of catalysts to dramatically enhance the electro-catalytic activity and durability of SOFC cathodes. The SSG process is capable of penetrating and preserving complex backbone microstructures of porous electrodes, creating highly conformal coatings of controlled morphology, while tailoring the composition of the surface to improve catalytic properties and durability. For example, the application of an SSG coating of PrOx to a La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) cathode has reduced the polarization resistance from 1.136 to 0.117 Ω cm2 at 600 °C and the degradation rate from 1.13 × 10−3 to 2.67 × 10−4 Ω cm2 h−1 at 650 °C. In addition, a continuous improvement in electrode performance is demonstrated as the thickness of the coating is increased, corresponding to the linear addition of catalyst. This first application of the SSG technique to SOFC systems opens the door for the controlled surface modification of porous components in electrochemical systems.