The performance of solid oxide cells (SOC) that employ mixed ionic-electronic conductors such as LSCF is typically limited by reaction with conventional stabilized-zirconia electrolytes. Ceria-based diffusion barrier layers prevent undesirable reactions and are thereby enhancing the electrochemical activity and durability of such electrodes. Recently, the implementation of physical thin-film methods to fabricate sub-micrometer barrier layers has led to strongly improved performance with respect to traditional fabrication methods. However, scalable and cost-effective manufacturing processes have not been proved to result in layers with sufficient quality, preventing the implementation of these improved barrier layers in commercially available cells. This study demonstrates the scalability of efficient barrier layers based on magnetron sputtering combined with rapid thermal processing (RTP). This approach reduces both the time and energy consumption compared to conventional processes. Electrochemical performance tests conducted on button cells recorded 1.26 W · cm⁻² and 1.54 A · cm⁻² at 0.7 and 1.3 V in fuel cell and electrolysis mode at 750 °C, respectively, which represents >30% increase compared to conventional reference cells. When scaled up to large-area cells (12x8 cm2), the RTP-treated cells measured as part of short stacks achieved up to approximately a 60% improvement in fuel cell conditions and 30% in electrolysis conditions compared with their reference counterparts at 650 ºC. The combination of magnetron sputtering and RTP offers a faster, scalable manufacturing process for high-performance SOCs, providing a viable route for large-scale production of high-performance barrier layers based on thin film technology.