Implications of Cation Interdiffusion between Double Perovskite Cathode and Proton-Conducting Electrolyte for Performance of Solid Oxide Fuel Cells

Chemical compatibility and cation interdiffusion between the double perovskite cobaltites RBaCo2O6-delta (R = Gd, Pr) and proton-conducting electrolyte BaZr0.8Y0.2O3-delta were studied. Chemical interaction was found to occur already at 1100 degrees C as a result of the partial dissolution of RBaCo2O6-delta (R = Gd, Pr) in BaZr0.8Y0.2O3-delta. Analysis of the element distribution along the cross sections of diffusion couples RBaCo2O6-delta(R = Gd, Pr)|BaZr0.8Y0.2O3-delta showed strong interdiffusion of cations, with cobalt being the most mobile one. Its diffusion depth in the electrolyte reaches up to several hundreds of micrometers. The addition of NiO as a sintering aid to BaZr0.8Y0.2O3-delta promotes cation diffusion especially through the grain boundary mechanism, increasing the diffusion depth of Co. The possible implications of cation interdiffusion on the performance of proton-conducting SOFCs are discussed based on the results obtained.

Automated summary

Chemical compatibility and cation interdiffusion between RBaCo2O6-delta (R = Gd, Pr) and BaZr0.8Y0.2O3-delta were studied. The study found that chemical interaction occurs at 1100 degrees C, leading to partial dissolution of RBaCo2O6-delta (R = Gd, Pr) in BaZr0.8Y0.2O3-delta. Cation interdiffusion, with cobalt being the most mobile, was observed along the cross sections of the diffusion couples. Addition of NiO as a sintering aid promoted cation diffusion, increasing the diffusion depth of Co. The implications of cation interdiffusion on proton-conducting solid oxide fuel cells were discussed based on the results obtained.