First-principles calculations based on the density functional theory are used to study the electronic structure of LaNiO3 perovskite for application of cathode material in solid oxide fuel cell. Our results show that bulk LaNiO3 exhibits metallic behavior. For 1x1x1 LaNiO3 unit cell, increasing in-plane strain leads to the increase in the density of states (DOS) at the Fermi level. | VNU Journal of Science: Mathematics – Physics, Vol. 33, No. 3 (2017) 25-29 First-principles Calculations on Electronic Properties of LaNiO3 in Solid Oxide Fuel Cell Cathodes Pham Ba Duy*, Nguyen Duy Huy, Bach Thanh Cong Computational Materials Science Laboratory, Faculty of Physics, VNU University of Science, 334 Nguyen Trai, Hanoi, Vietnam Received 09 August 2017 Revised 30 August 2017; Accepted 19 September 2017 Abstract: First-principles calculations based on the density functional theory are used to study the electronic structure of LaNiO3 perovskite for application of cathode material in solid oxide fuel cell. Our results show that bulk LaNiO3 exhibits metallic behavior. For 1x1x1 LaNiO3 unit cell, increasing in-plane strain leads to the increase in the density of states (DOS) at the Fermi level. On the other hand, the DOS at the Fermi level for 2x2x2 LaNiO3 supercell first increases with the strain up to 3% and then decreases for larger values of the strain. The difference between the electronic structure of the 2x2x2 supercell and that of the 1x1x1 unit cell is attributed to the rotations of NiO6 octahedra. Keywords: Solid oxide fuel cell, density functional theory, LaNiO 3 perovskite, electronic structures, strain. 1. Introduction The perovskite LaNiO3 is frequently used as cathode material for solid oxide fuel cells due to its high temperature stability, acceptable thermal expansion, and the ability to enhance oxygen reduction reaction [1-4]. At cathode-electrolyte interface, the induced strain caused by lattice mismatch between LaNiO3 and electrolyte materials is expected to give rise to the reconstructions of the electronic structures of LaNiO3. Such electronic reconstructions could be important as they are tightly linked with the formation of oxygen vacancy and the conduction of oxygen ions, which greatly affect the operation of the fuel cell. On the other hand, previous publications have reported that the NiO6 octahedra rotated in bulk LaNiO3, .
