SOFCs with dual-ion conducting electrolytes: A theoretical study

This study focuses on the properties of solid oxide fuel cells (SOFC) dual-ion (O²¿/H¿) conducting perovskite and double perovskite oxides using Density Functional Theory (DFT), Nudged Elastic Band (NEB) and Principal Component Analysis (PCA) methods, which have potential applications in the intermediate-temperature solid oxide fuel cells. Materials considered in this research have lattice parameters of 4.00-4.30 Å and band gap of 2.5-4.2 eV, which prove the feasibility of being used as an insulating electrolyte. Energy values needed for the formation of vacancies are 1.2-2.8 eV and hydration energy ranges from -0.4 to -1.1 eV, which shows better capability of hydrogen incorporation. Migration energy barriers show that oxide-ion conduction takes place within the range of 0.6-1.1 eV, but proton conduction happens within 0.3-0.7 eV, which shows higher proton conductivity. Dielectric constant values are 20-200 and decrease migration barriers up to 40% and increase ionic conductivities up to one magnitude. According to PCA analysis, descriptors play a role in 85% of conductivity differences.