3D Self‐Architectured Steam Electrode Enabled Efficient and Durable Hydrogen Production in a Proton‐Conducting Solid Oxide Electrolysis Cell at Temperatures Lower Than 600 °C

at 1.6 V. Instead of fast degradation in most O-SOECs, performance enhancement is observed during electrolysis at an applied voltage of 1.6 V at 500 °C for over 75 h, attributed to the "bridging" effect originating from reorganization of the steam electrode. The H-SOEC with SAUP steam electrode demonstrates excellent performance, promising a new prospective for next-generation steam electrolysis at reduced temperatures.