Stability of ceramic matrix materials in molten hydroxide under oxidizing and reducing conditions

• Published in: International journal of hydrogen energy 2021-04, Vol.46 (28), p.14898-14912
• Main Authors: Anisur, M.R., Aphale, Ashish, Reisert, Michael, Dubey, Pawan Kumar, Heo, Su Jeong, Hong, Junsung, Patil, Kailash, Xu, Hui, Yuh, Chao-Yi, Singh, Prabhakar
• Format: Article
• Language: English
• Subjects: Ceramic matrix stability; High-temperature water electrolysis; Molten hydroxide; Phase change
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2020.08.182

The degradation mechanism of ceramic matrix materials used as molten hydroxide electrolyte support for steam electrolysis cells, is not well documented. In this study, we have investigated the structural and chemical stability of non-oxide and oxide ceramics (SiC, YSZ, Li2ZrO3, LiAlO2, and SrZrO3) in the presence of molten hydroxide under oxidizing and reducing conditions with humidity levels of 3 and 85% at 550 °C. SiC, YSZ, Li2ZrO3 and LiAlO2 showed structural and chemical changes due to dissolution of the ceramic particles in the hydroxide melt followed by precipitation. The SrZrO3 powder, on the other hand, remained both chemically and structurally stable during 500 h test under both oxidizing and reducing atmospheres. The findings of a stable ceramic matrix in molten hydroxide contribute to the enhancement of the durability and performance of intermediate temperature water electrolysis system. •Conventional ceramic electrolyte matrix shows instability in hydroxide melt.•Matrix phase changes through dissolution and subsequent precipitation in the melt.•The SrZrO3 matrix shows chemical and structural stability in hydroxide melt.