Novel PrBa0.9Ca0.1CO2-xZnxO5+δ double-perovskite as an active cathode material for high-performance proton-conducting solid oxide fuel cells

Zn-doped PrBa0.9Ca0.1CO2-xZnxO5+delta (PBCCZx) with x equaling 0, 0.05, 0.10, 0.15, and 0.2, designated as PBCCZ00, PBCCZ05, PBCCZ10, PBCCZ15, and PBCCZ20, respectively, are prepared and investigated in the aspects of crystal structure, thermal expansion behavior, defect chemistry, and electrochemical performance as the cathode of proton-conducting solid oxide fuel cells (H-SOFCs). With the increase of the content of doped Zn, the thermal expansion coefficient of PBCCZx remains unchanged essentially. But the bulk and surface concentrations of oxygen vacancy are increased, and the maximum power density (MPD) of the cells at 750 degrees C with PBCCZx-BaZr0.1Ce0.7Y0.1Yb0.1O3-delta (BZCYYb) composite cathodes are improved from 335 (x = 0) to 876 (x = 0.15) mW cm(-2). With the PBCCZ15-BZCYYb cathode, the MPD of the cell increases with temperature from 299 mW cm(-2) at 600 degrees C to 876 mW cm(-2) at 750 degrees C with a reduction of cell polarization resistance from 0.68 to 0.04 Omega cm(2) accordingly. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.