Proton-hole mixed conduction in Ce0.95Yb0.5SrO3 ceramic was studied under an asymmetrical atmosphere, with respect to H species. An electrochemical cell of the form, (I) 1%H, Pt | ceramic | Pt, O2-Ar (II), was constructed. Electrochemical H permeation through this sample was examined under open-circuit and closed-circuit conditions. When the circuit was closed, the H or water vapor evolution rates at the cathode decreased with increasing partial pressure of O in the cathode. Conductivity data for various O partial pressures confirmed that the main charge carrier apart from protons was a positive hole, and that the present ceramic behaved like a proton-hole mixed conductor under asymmetrical conditions. When the circuit was open, water vapor evolved spontaneously, and the formation rate increased with increasing O partial pressure in compartment (II). The results indicated that this cell was short-circuited via hole conduction in the bulk, and that H permeated electrochemically from compartments (I) to (II).

S.Hamakawa, T.Hibino, H.Iwahara: Journal of the Electrochemical Society, 1994, 141[7], 1720-5