Boron deposition and poisoning of La0.8Sr0.2MnO3 oxygen electrodes of solid oxide electrolysis cells under accelerated operation conditions. (21st January 2016)

• Record Type: Journal Article
• Authors: Chen, Kongfa; Hyodo, Junji; Ai, Na; Ishihara, Tatsumi; Jiang, San Ping
• Is Part Of: International journal of hydrogen energy. Volume 41:Number 3(2016)
• Page Start: 1419
• Page End: 1431
• Publication Date: 2016-01-21
• Subjects: Solid oxide electrolyzer (SOEs) -- Solid oxide electrolysis cells (SOECs) -- LSM oxygen electrode -- Borosilicate glass -- Boron deposition and poisoning -- Interface; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2015.11.013
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The effect of boron species from borosilicate glass sealant on the electrocatalytic activity and microstructure of La0.8 Sr0.2 MnO3 (LSM) oxygen electrodes is studied for the first time under accelerated solid oxide electrolysis cell (SOEC) operation conditions at 800 °C. The presence of volatile boron species has remarkable detrimental effect on the electrochemical activity of LSM oxygen electrode for the O2 evolution reaction (OER). After polarization at 200 mA cm −2 for 2 h, the electrode polarization and ohmic resistances increase rapidly from ∼40 and 1.2 Ω cm 2 to 614 and 33 Ω cm 2, respectively. Under the anodic polarization conditions, there is an accelerated Sr segregation and boron deposition preferentially occurs at the electrode/electrolyte interface, forming lanthanum borates and manganese oxide. Boron deposition and reaction is driven to the interface region due to the increased activity and energetics of lanthanum at LSM lattice sites at the electrode/electrolyte interface under anodic polarization conditions, accelerating the disintegration and delamination of the LSM electrode. The results indicate the potential detrimental effect of volatile boron on the electrochemical activity and stability of LSM oxygen electrodes of solid oxide electrolyzers. Highlights: Boron deposition and poisoning on LSM oxygen electrodes is studied. Under solid oxide electrolysis mode, boron reacts with lanthanum, forming LaBO3 . Boron deposition preferentially occurs at the electrode/electrolyte interface. Boron deposition is kinetically driven by the increased activity of lattice La.