Defect Chemistry of La2Ni1-xMxO4 (M = Mn, Fe, Co, Cu): Relevance to Catalytic Behavior

Computational Screening of La2NiO4+δ Cathodes with Ni Site Doping for Solid Oxide Fuel Cells

Doping on the crystal structure is a common strategy to modify electronic conductivity, ion conductivity, and thermal stability. In this work, a series of transition metal elements (Fe, Co, Cu, Ru, Rh, Pd, Os, Ir, and Pt) doped at the Ni site of La₂NiO_4+δ compounds as cathode materials of solid oxide fuel cells (SOFCs) are explored based on first-principles calculations, through which the determinant factors for interstitial oxygen formations and migrations are discussed at an atomistic level. The interstitial oxygen formation and migration energies for doped La₂NiO₄ are largely reduced in contrast to the pristine La₂NiO_4+δ, which is explained by charge density distributions, charge density gradients, and Bader charge differences. In addition, based on a negative correlation between formation energy and migration barrier, the promising cathode materials for SOFCs were screened out between the doped systems. The Fe-doped structures of x = 0.25, Ru-doped structures of x = 0.25 and x = 0.375, Rh-doped structures of x = 0.50, and Pd-doped structures of x = 0.375 and x = 0.50 are screened out with interstitial oxygen formation energy less than -3 eV and migration barrier less than 1.1 eV. In addition, DOS analysis indicates that doping to La₂NiO_4+δ also facilitates the electron conductions. Our work provides a theoretical guideline for the optimization and design of La₂NiO_4+δ-based cathode materials by doping.

Fabrication of La2NiO4 nanoparticles as an efficient bifunctional cathode catalyst for rechargeable lithium–oxygen batteries

LNO nanoparticles synthesized via a hydrothermal process are a promising bifunctional electrocatalyst for Li–O₂ batteries. The battery's discharge capacity of 14310.9 mA h g⁻¹ at a current density of 0.16 mA cm⁻², is higher than that of Pechini-LNO particles and pure SP.

Synthesis of shape-controlled La2NiO4+δ nanostructures and their anisotropic properties for oxygen diffusion

Control over the shape of La₂NiO_4+δ nanostructures using a reverse microemulsion method and the effect on their oxygen diffusion properties.

Doped lanthanum nickelates with a layered perovskite structure as bifunctional cathode catalysts for rechargeable metal-air batteries

Rechargeable metal-air batteries have attracted a great interest in recent years because of their high energy density. The critical challenges facing these technologies include the sluggish kinetics of the oxygen reduction-evolution reactions on a cathode (air electrode). Here, we report doped lanthanum nickelates (La2NiO4) with a layered perovskite structure that serve as efficient bifunctional electrocatalysts for oxygen reduction and evolution in an aqueous alkaline electrolyte. Rechargeable lithium-air and zinc-air batteries assembled with these catalysts exhibit remarkably reduced discharge-charge voltage gaps (improved round-trip efficiency) as well as high stability during cycling.