Delithiated states of layered cathode materials: doping and dispersion interaction effects on the structure

¹ Samara Center for Theoretical Materials Science, Samara University, Samara, Russia
² Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna, Russia
³ Saratov State University, Saratov, Russia

^* Corresponding author: eremin_roman@inbox.ru

Published online: 18 April 2018

Abstract

Here we present results of density functional theory (DFT) study of delithiated structures of layered LiNiO2 (LNO, Li12Ni12O24 model) cathode material and its doped analogue LiNi_0.833Co_0.083Al_0.083O2 (N₁₀C₁A₁, Li₁₂Ni₁₀CoAlO₂₄ model). The paper is aimed at independent elucidation of doping and dispersion interaction effects on the structural stability of cathode materials studied. For this purpose, the LNO and N₁₀C₁A₁ configurational spaces consisting of 87 and 4512 crystallographically independent configurations (obtained starting from 2×2×1 supercell of R-3m structure of LNO) are optimized within a number of DFT models. Based on a comparison of the calculated dependencies for the lattice parameters with the results of in situ neutron diffraction experiments, the most pronounced effect of cathode material stabilization is due to the dispersion interaction. In turn, the doping effect is found to affect cathode structure behavior at the latest stages of delithiation only.