Electronic structures and electrode potentials of layered lithium insertion electrodes by the first principles calculation

Abstract

In order to evaluate intercalation voltage of LiMO 2 and to understand the electronic mechanism determining the voltage, two kinds of first principles calculations are combined. The voltage is quantitatively evaluated by total energy calculations using the full-potential linearized augmented plane wave method. The electronic structures are analyzed by molecular orbital calculations on model clusters using the discrete variational Xα method. Two factors determining the voltage are estimated separately: 1) the effective electrostatic potential at the Li position, and 2) the energy of the highest occupied molecular orbital. They are related to the energies required to remove a Li ion and an electron from LiMO 2 , respectively. The sum of these two factors reproduces well the theoretical voltage. Moreover, it agrees well with experimental voltage.