Structural Properties of Li_xMn₂O₄ as Investigated by Molecular Dynamics and Density Functional Theory

Abstract

We performed density functional calculations and molecular dynamics (MD) simulations to study the structural properties of LiMn2O4. The periodic density functional calculations revealed that LiMn2O4 had a locally distorted structure due to the different local structures around Mn3+ and Mn4+. The trajectory plots of Mn3+ in Li0.4Mn2O4 at 300 K obtained by MD simulations indicated that Mn3+ ions moved easily from the 16d site, which is the original position of Mn3+ ion in the spinel structure. It was observed that the Mn3+ ions moved with greater ease at low lithium concentrations, resulting in unstable Li x Mn2O4 structures.

A review of conduction phenomena in Li-ion batteries

“…First-principles calculations [62,104,105,[131][132][133] can be a powerful tool for understanding atomic scale diffusion in cathode particles and providing detailed insight into diffusion mechanisms and structural properties. First-principles calculations of Li x CoO 2 diffusivity have been conducted at varying intercalation levels of Li (0 ≤ x ≤ 1), elucidating the reason for the wide variation of diffusivity based upon the activation barrier change and divacancy diffusion mechanisms (also, see Table 7) [131,134].…”

Diffusion of Li atoms in LiMn2O4 - A structural point of view -

“…The potential function used was of Gilbert-Ida type. 34), 35) The 16d sites are assumed to be occupied by Mn III and Mn IV in equal numbers. They are distributed using the random number table before commencing the simulation (model I).…”

Jahn–Teller distortion and electronic structure of LiMn2O4

“…The lithium diffusion coefficient was measured and Monte Carlo simulations were performed to understand the lithium diffusion mechanism [2,3]. Molecule dynamics were also performed to simulate the lithium diffusion in Li x Mn 2 O 4 [4,5]. Those studies revealed that lithium diffuses in a three-dimensional network diffusion pathway within the spinel structure.…”