Localized lattice strain in perovskite oxides for enhanced oxygen reduction reaction kinetics in solid oxide fuel cells

The cathode of a solid oxide fuel cell (SOFC) must exhibit both high activity and robust durability for effective utilization in electrochemical oxygen reduction reaction (ORR). To address this challenge, we present a novel strain engineering strategy that involves the creation of nanoscale local lattice strain microdomains to further enhance the ORR kinetics. Specifically, Ga cations are introduced into some of the B-sites of the perovskite Pr0.4Sr0.6Fe0.5Co0.5O3-delta (PSFC). Benefiting from local lattice strain engineering, the bulk oxygen migration coefficient of the locally strained PSFC sample is significantly enhanced, reaching twice that of the pure PSFC sample at 650 degrees C. Moreover, the polarization impedance of PSFC (0.102 Omega & sdot;cm2) is more than twice that of Pr0.4Sr0.6Fe0.4Co0.5Ga0.1O3-delta (PSFCG, 0.043 Omega & sdot;cm2) at 800 degrees C. Microscopic structural analyses and computational calculations indicate that the optimized electronic structure of the rich micro-strain catalyst reduces the bond energy of adjacent B-O bonds and the oxygen transport barrier. This work demonstrates a practical local lattice micro-strain engineering strategy and provides a new approach for improving the performance of ORR electrocatalysts.