Investigation of Oxygen Transport Paths in Geometrically Defined Thick-Film Composite Pt Electrodes on YSZ. Issue 8 (8th June 2016)

• Record Type: Journal Article
• Authors: Zheng, Yingjing; Sauter, Ulrich; Moos, Ralf
• Is Part Of: Journal of the Electrochemical Society. Volume 163:Issue 8(2016)
• Page Start: F877
• Page End: F884
• Publication Date: 2016-06-08
• Subjects: electrode processes -- oxygen -- platinum -- transport phenomena -- zirconia; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.1081608jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : Thick-film platinum (Pt) model electrodes with defined geometry screen-printed on yttria stabilized zirconia (YSZ) substrate were investigated to identify oxygen reactions and transport pathways in the Pt|YSZ electrode system. A 3D reconstruction of the electrode based on Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) data was made to confirm that no percolating pores exist. Electrochemical impedance spectroscopy (EIS) was performed at 800°C and oxygen partial pressures ( p O2 ) between 10 −4 and 1 bar. The experimental data was interpreted using a Randles equivalent circuit. By variation of electrode area and three phase boundaries as well as electrode thickness, two oxygen transport pathways were found: an electrode surface path which contributes to the conductivity mostly at low p O2 and an electrode bulk path that represents the dominating path at high p O2 . An advanced electrode layout enabled the separation of the transport pathways and confirmed that the two paths are parallel.