Ionic conductivity evolution at strained crystal interfaces in solid oxide fuel cells (SOFCs)

Ionic conductivity along strained heterostructural interfaces can be enhanced by several orders of magnitude due to lattice mismatch. Although extensive experimental and theoretical investigations have been focused on the correlation between lattice strain and ionic conductivity, exact depth profiles of ionic conductivity are still lacking. In this report, we develop, for the first time, an exact model for investigating the depth evolution of ionic conductivity enhancement as induced by interfacial lattice strain in SOFCs. The model allows for analytically evaluating the correlation between lattice strain and ionic conductivity enhancement in isotropic orthorhombic lattice. In particular, temperature, Young's modulus, Poisson's ratio and lattice constant are incorporated into our analysis, the validity of which has been verified with prototype ionic conductors including YSZ, STO, CeO, etc.