Proton Distribution Modulated Surface Potential in Ceramic Proton Conductors Revealed by Near-Ambient Pressure X-ray Photoelectron Spectroscopy

To study the proton distribution of BaZr0.9Y0.1O3-δ (BZY10) electrolyte, an external 1 V voltage was applied on the working electrode (WE), and the counter electrode (CE) is grounded. In situ near-ambient pressure X-ray photoelectron spectroscopy (XPS) measurements were conducted at Beamline 9.3.2, Advanced Light Source, Lawrence Berkeley National Laboratory, California. Electrochemical impedance spectroscopy (EIS) experiments were performed using a Potentiostat (PCI4/750, Gamry). XPS and EIS were performed at two temperatures of about 500 K and 670 K in 200 mTorr water vapor, respectively. The XPS folder contains the XPS data recorded at three different locations: the working electrode (WE), the center of electrolyte (center) and the counter electrode (CE). The EIS folder contains the impedance spectra measured at two temperatures.