Calibrating density functionals with DMol3 applied on lithium oxide battery

Abstract

Density functional theory - based methods constitute part of the computational techniques considered for finding energy, temperature, pressure, density, electronic structure, and more, of materials and other systems. There is not a general density functional for solving either one or another system, rather there are approximations to the exchange-correlation functional designed to apply this theory, and the density functional for the system in study is usually selected through the Jacob’s Ladder. The purpose of this article is to calibrate by means of selecting multiple density functionals, for calculating potential energy curves on a specific system, and comparing these results with literature values to determine the most suitable functional. With this theory, when a calculation becomes cyclical means that it does not converge after thousands of steps or iterations. The use of thermal smearing calculations can achieve the convergence of the molecular systems. The density functional is calibrated at insignificant thermal smearing values (around 0.005 Hartrees), because the calculated minimum energy is still consistent against experimental values. This level of theory allows searching for stable reaction products. Among the interactions developed to find a suitable density functional are Li + O, Li + O₂, Li + CO, 2 LiO^– + C₃₈H₈.  We select GGA-PBE-Grimme as the most suitable density functional. The resulting information is for applying it to infer about charge/discharge of a rechargeable battery, according to the porosity of the cathode.