First-principles study of CoMn2O4-Cr2O3 coherent interface analysis

Abstract

The CoMn2O4 coating can effectively protect the metallic interconnect of solid oxide fuel cells, which come into direct contact with the naturally occurring Cr2O3 on the matrix surface. However, the properties of CoMn2O4-Cr2O3 interface remain unclear. In this study, the first-principles calculations are utilized to investigate the atom staking, stability, and electronic properties of the CoMn2O4(101)-Cr2O3(001) interface, along with examining the diffusion behavior of Cr atom at the interface. By comparing the adhesion work, the most stable model is determined. Based on the most stable model, the results of electronic structure analysis show that Mn atoms providing vacant orbitals near the conduction band minimum, enhancing the overall conductivity of the interface. The projected density of states metal atoms validates the formation priority of Cr-O bonds. The climbing image nudged elastic band (CI-NEB) method is used to simulate the interstitial diffusion properties of Cr atom at the interface, revealing that the energy barrier is about 3.05 eV. The diffusion coefficients of Cr atom are calculated accordingly. The obtained results can provide theoretical support for relevant experiments and deepen the understanding of the protective effects of spinel coatings on metallic interconnects of solid oxide fuel cells.