Durability of high performance Ni–yttria stabilized zirconia supported solid oxide electrolysis cells at high current density

• Published in: Journal of power sources Vol. 262; pp. 316 - 322
• Main Authors: Hjalmarsson, Per, Sun, Xiufu, Liu, Yi-Lin, Chen, Ming
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 15.09.2014
• Subjects: Chemistry; Degradation; Durability; Electrochemical impedance spectroscopy; Electrochemistry; Electrodes; Electrolytic cells; Exact sciences and technology; General and physical chemistry; Nickel; Yttria stabilized zirconia; Zirconium dioxide; Cerium Oxides; Solid oxide electrolysis cell; Co-electrolysis; Oxygen electrode; Mixed conductors; Solid electrolyte; Lanthanum Oxides; Durability; Mixed ionic electronic conductor; Transition metal; Stabilized zirconia; Gadolinium Oxides; Degradation; Chromium Oxides; Quaternary compound; Yttrium Oxides; Cermet; Composite electrode; Electrolysis cell; Nickel; Strontium Oxides; Modified material; Electrochemical impedance spectroscopy
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2014.03.133

We report the durability of a solid oxide electrolysis cell (SOEC) with a record low initial area specific resistance (ASR) and a record low degradation rate. The cell consists of a Ni-yttria stabilized zirconia (YSZ) cermet as support and active fuel electrode, a YSZ electrolyte, a gadolinia doped ceria (CGO) inter-diffusion barrier, and a strontium doped lanthanum cobaltite (LSC)-CGO composite oxygen electrode. The cell was tested at 800[degrees]C and -1 A cm super(-2) converting 31% of a 0.1:0.45:0.45 mixture of H sub(2):H sub(2)O:CO sub(2 ) for approximately 2700 h, demonstrating an initial ASR of 200 m[Omega] cm super(2) and a steady degradation rate of [< or =]12 mV (or 0.9%) per 1000 h. Electrochemical impedance spectroscopy (EIS) was used to study in situ changes in the electrochemical response of the cell and the retrieved data was treated to deconvolute resistive contributions from the physiochemical processes occurring within the cell. The results showed rapid initial fuel electrode degradation during the first 350 h followed by partial reactivation. The serial resistance was found to increase with time but in an exponentially decaying behavior. A discussion is made based on the detailed electrochemical results together with post-mortem microstructural analysis.