A large-scale simulation method on complex ternary Li-Mn-O compounds for Li-ion battery cathode materials

摘要

To meet the requirement of large-scale simulation technics for Li-ion battery electrode materials, we introduce the charge-transfer modified embedded-atom method (CT-MEAM) in which the complex nature of the chemical bonding in transition metal (TM) oxides is described as a balance between metallic/covalent and ionic contributions by MEAM and a variable-charge model, respectively. The method is applied to Li2MnO3, and the parameterization is performed through fitting the energy-strain curves of Li2MnO3 under uniaxial, biaxial and hydrostatic strains to a training set from ab initio density-functional theory calculations. The CT-MEAM prediction of the critical physical properties such as charge states and redox potentials match quite well with the ab initio results in various Li-Mn-O compounds beyond Li2MnO3. The constructed Li-Mn-O phase diagram is also qualitatively consistent with the ab initio reference work. The excellent transferability ensures use of the present method for a wide range of oxidation states in complex ternary TM oxides. Therefore, it will facilitate large-scale atomistic calculations required for the optimal design of many TM oxide applications including lithium-ion battery cathode materials. (C) 2015 Elsevier B.V. All rights reserved.