Deficiency of hydrogen production in commercialized planar Ni-YSZ/YSZ/LSM-YSZ steam electrolysis cells

Deficient, or non-linear hydrogen production is for the first time experimentally observed in large-scale planar Ni-YSZ/YSZ/LSM-YSZ steam electrolysis cells. The apparent coinciding of the concentration polarization and Faraday efficiency decrease at certain current density (-0.5Acm(-2) or -0.6Acm(-2) for selected steam content) indicates that steam starvation appears to affect the hydrogen production's linearity, which in essence the Ni/NiO redox process is believed to play a role in such normal SOEC operations. The SOEC survives 10h extreme polarization through electric conduction and oxygen vacancy transportation. Rational SOEC working mode is recommended accordingly. The present work is complementary for the general application of the Faraday's Law to estimate hydrogen production, and to further evaluate the SOEC's overall characteristics. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Deficient or non-linear hydrogen production is observed for the first time in large-scale steam electrolysis cells. Steam starvation affects the linearity of hydrogen production, with the Ni/NiO redox process playing a role in SOEC operations. The SOEC shows endurance to 10 hours of extreme polarization through electric conduction and oxygen vacancy transportation.