Study of High-Performance Solid Oxide Electrolytic Cell Based on BaZr0.8Y0.2−xSmxO3−δ Proton Conductor Electrolyte

To address the low conductivity of yttrium-doped BaZrO 3 (BZY) proton-conducting electrolytes, this study synthesized Sm-doped BaZr 0.8 Y 0.2− x Sm x O 3−δ ( x  = 0–0.15) via sol–gel, systematically investigating the effects of Sm doping on the structural, morphological, and electrochemical properties. Key findings reveal that optimal Sm doping ( x  = 0.05) produces homogeneous grains (relative density: 97.39%), reduces lattice parameters (4.208 Å), and enhances conductivity to 12.4 × 1 0 −3 S cm −1 at 650°C, which is 63% higher than that of undoped BZY (7.6 × 10 −3 S cm −1 ). The anode-supported SOEC based on BaZr 0.8 Y 0.2− x Sm x O 3−δ ( x  = 0.05) prepared by the co-pressing method shows good performance at low temperatures: the electrolytic current reaches up to 0.31 A cm −2 at 650°C and a voltage of 1.5 V (34.8% higher than undoped cells), and a hydrogen production rate of 129.58 mL cm −2  h −1 . This work demonstrates that controlled Sm doping in BZY significantly boosts ionic transport and SOEC efficiency at 650°C, providing a viable strategy for next-generation proton-conducting electrochemical devices.