Fabrication and electrochemical performance of reversible metal-supported solid oxide cells via atmospheric plasma spraying

This study investigates the fabrication and electrochemical performance of reversible metal-supported solid oxide cells (RSOCs) developed using atmospheric plasma spraying (APS) at the National Atomic Research Institute (NARI). The RSOC architecture features a tri-layer composite electrolyte composed of Sm-doped ceria (SDC) and Sr- and Mg-doped LaGaO₃ (LSGM), which enhances ionic conductivity and reduces polarization resistance. The 10 × 10 cm² cells deliver peak power densities of 660, 798, and 859 mW cm⁻² at 650, 700, and 750 °C, respectively, under 0.7 V fuel cell operation. Long-term stability testing at 700 °C over 1200 h reveals a degradation rate of approximately 1 % k⁻¹ h⁻¹, demonstrating excellent durability. In electrolysis mode, each RSOC generates hydrogen at a rate of 0.6 L min⁻¹ at 700 °C under 1.17 V and 80 A, achieving an efficiency of 88.03 % based on the lower heating value (LHV). The composite SDC/LSGM/SDC electrolyte exhibits an ionic conductivity of 0.0435 S cm⁻¹ at 750 °C, which outperforms that of LDC/LSGM (0.0308 S cm⁻¹), and displays a lower activation energy of 0.792 eV. A 100-hour preliminary electrolysis test indicates negligible degradation, confirming the structural integrity and dual-mode functionality of the RSOC. These results highlight APS-fabricated RSOCs as a promising platform for efficient and durable energy conversion and storage at intermediate temperatures.