A second nearest-neighbor modified embedded-atom method combined with a charge equilibration interatomic potential for the Li–Ni–O ternary system and Li diffusion in lithium-ion battery cathode structure

Abstract

Ni is a key element, especially in layered cathodes, to achieve a large capacity and a reduced cost. To analyze and gain insight into such cathode materials, large-scale atomistic simulations such as molecular dynamics (MD) are a suitable method. In this paper, a Li–Ni–O interatomic potential has been developed on the basis of the second nearest-neighbor modified embedded-atom method (2NNMEAM) formalism combined with a charge equilibration (Qeq) concept. This potential reproduces fundamental properties (thermodynamic, structural, elastic) of lithium-nickel and nickel oxide binary systems as well as the lithium-nickel oxide ternary system in good agreement with experiments and first-principles calculations. Lithium diffusion properties such as the activation energy for lithium migration and diffusion coefficients in Li1-xNiO2 layered structures are also calculated by a MD simulation and found to show the same tendency as observed in experiments. The potential can be utilized for simulating various material phenomena in the Li-ion battery (LIB) system and can be easily extended to the mainly used Li-[Ni,Mn,Co]-O quinary system, in combination with already developed Li–Mn–O and Li–Co–O ternary potentials based on the same formalism.