Surface Modification of La0.6Sr0.4Co0.2Fe0.8O3-δ Cathode by Atomic Layer Deposition of La0.6Sr0.4CoO3-δ for High-Performance Solid Oxide Fuel Cells

Lowering the working temperature of solid oxide fuel cells (SOFCs) is necessary to avoid undesirable reactions between the cells’ elements and to guarantee long-term stability and a short start-up time. At low temperatures (<650°C), the cathode is considered the main resistive factor for global cell performance, because the oxygen surface exchange is a rate-determining step in the oxygen reduction reaction at the cathode. Modifying the cathode surface with catalytic nanoparticles or thin films has been very effective in improving the surface kinetics of the cathode. Among the surface modification techniques, atomic layer deposition (ALD) has many advantages, such as a low deposition temperature (<250°C), precise control of layer thickness, and uniform distribution. In this study, we modified the surface of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) with ALD of La_0.6Sr_0.4CoO_3-δ (LSC). The ALD LSC was added to the surface of the LSCF cathode by pulsed laser deposition in an anode-supported SOFC cell. As a result, at 600°C, the maximum power density of the ALD LSC-treated cell increased to 250 mW/cm² compared to the 198 mW/cm² density displayed by the bare cell. We will discuss the performance enhancement of the LSCF surface-treated with ALD LSC layers in terms of electrode kinetics and fuel cell performance.