Electrochemical Performance and Degradation Mechanisms of BaCe 0.7 Zr 0.1 Y 0.2 O 3‐δ /BaZr 0.8 Y 0.2 O 3‐δ Based Tubular Protonic Ceramic Electrolysis Cells and Stacks for Stable Hydrogen Production

at 1.3 V and 550 °C. The assembled 4-cell-stack in combined serial and parallel connections achieves 58 W at 650 °C. Several thermal cycles to room temperature of the single cell and stack are both achieved to show structural stability and reliability. All these results show excellent stability of BZY material and Ni-BCZY electrode supported tubular structure for PCEC applications.