Fluoride-Based Anion Doping: A New Strategy for Improving the Performance of Protonic Ceramic Conductors of the Form BaZrO₃

A new strategy is reported to improve the performance of BaZrO3-based protonic ceramic conductors by substitution on the anion sublattice, specifically replacing F- in the O2- site. The F--doped material exhibited higher conductivity under both reducing and oxidizing atmospheres compared to the undoped oxide. Ab initio calculations and X-ray photoelectron spectroscopy results showed that the improved performance can be attributed to weakened chemical bonding between the cations (A or B site) and the oxygen ions as a result of F- doping, resulting in improved oxygen mobility. Finally, improved performance was demonstrated by using BaZr0.8Y0.2O3-delta-sigma F sigma (sigma=0.1) as the electrolyte in protonic ceramic fuel cells measurements. The anions doping strategy shows great promise for the development of a new generation of high-performance electrolyte materials.