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

Abstract A new strategy is reported to improve the performance of BaZrO 3 ‐based protonic ceramic conductors by substitution on the anion sublattice, specifically replacing F − in the O 2− 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 BaZr 0.8 Y 0.2 O 3‐ δ ‐ σ F σ (σ=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.