Average voltage, energy density, and specific energy of lithium-ion batteries - Calculation based on first principles

The theoretical average voltage, energy density (energy per volume), and specific energy (energy per mass) based on the active electrode material have been calculated from first principles for two types of rechargeable lithium-ion batteries. In the charged state the two batteries consist of LiC6 and MO2 electrodes (M = Mo and Ni). The calculation was performed using the Linearized augmented plane wave crystal code WIEN95 based on density functional theory (DFT). The structure was calculated by Varying the unit cell volume of the experimentally known crystallographic data with respect to the total energy. The calculated results are compared with measured values. The temperature dependence of the average voltage, energy density, and specific energy was demonstrated to be of minor importance. In the case of the LiC6/NiO2 battery this was done by calculating the vibrational energy contribution to the enthalpy change using the cluster approximation and the Amsterdam density functional (ADF) molecular code based on DFT. The agreement between theoretical and experimental values opens up the use of first principles quantum chemistry in battery technology.