(Invited) Lessons Learned from Operating a Solid Oxide Electrolysis Cell at 1.25 a/cm2 for One Year

Conventional Ni/yttria stabilized zirconia (YSZ) fuel electrode supported solid oxide electrolysis cells (SOECs) demonstrate acceptable long-term durability when operated at below -1 A/cm2. These cells suffer however severe degradation at above -1 A/cm2, where a large part of the cell resistance increase is associated with the Ni/YSZ electrode. In this work, by introducing Ce0.8Gd0.2O2-d (CGO) nanoparticles into the Ni/YSZ electrode, we reduce the cell degradation down to 39 mV/kh when operated at 810oC and -1.25 A/cm2. A steam supply failure at 4000 h causes certain damage to the cell, resulting in higher degradation in the second half of the one-year period. A degradation-mitigation strategy is successfully tried out by increasing the operating temperature to 836oC eventually. The test is successfully terminated after reaching one year, demonstrating an average degradation rate of 39 mV/kh over the one-year period. The current work shows high potential for modifying conventional SOEC cells for use in high current density electrolysis applications.