Intercalation voltages for spinel LixMn2O4 (0≤x≤2) cathode materials: Calibration of calculations with the ONETEP linear-scaling DFT code

Density functional theory (DFT) has become an engine for driving ab-initio quantum mechanical simulations spanning a vast range of applications. However, conventional DFT has limitations of the accessible system size due to computational expense. Recent progress on linear scaling DFT methods has enabled us to investigate larger systems. In this paper, we investigate the numerical agreement between conventional DFT codes and ONETEP, a linear-scaling DFT code, for important materials properties particularly calculating the intercalation potential of spinel electrode materials. Modulating materials with high energy density is an important aspect that contributes to the significant gap in our knowledge of the factors. We provide typical simulation results based on calculated intercalation potentials for discharging the spinel LixMn2O4, which plays a key role in developing high energy density lithium-ion batteries. The structural properties obtained after geometry optimisation with CASTEP yielded materials with volume within 3 % and lattice parameters within 1 % relative error with experimental values. The average intercalation potentials calculated with the CASTEP and ONETEP codes are within 3 % agreement with each other.