Oxygen Non-Stoichiometry and Point Defect Equilibria in (La_1/6Pr_1/6Nd_1/6Gd_1/6Ba_1/6Sr_1/6)MnO_{3- δ}

In this work, the A-site of the common SOFC cathode La 0.8 Sr 0.2 MnO 3-δ (LSM) is modified with additional lanthanide and alkali elements, resulting in the composition (La 1/6 Pr 1/6 Nd 1/6 Gd 1/6 Ba 1/6 Sr 1/6 )MnO 3- δ . We show that the amount of oxygen released during reduction measured by thermo-gravimetric analysis is significantly greater for this “high entropy” perovskite oxide (HEPO) in comparison with La 2/3 Sr 1/3 MnO 3-δ , the latter having the same amount of total acceptor dopant and with a similar average A-site radius. The origins of enhanced reduction will be discussed.