DFT and KMC study of graphene as a benchmark material for Li-Ion battery applications

In recent years, many studies have explored modified or functionalized graphene, such as doped graphene or graphene composites, to enhance Li-ion battery performance. In contrast, our study focuses on pristine graphene to establish a fundamental understanding of its intrinsic properties, combining density functional theory (DFT) and kinetic Monte Carlo (KMC) simulations. This approach provides critical benchmarks for future material design. DFT reveals that lithium preferentially adsorbs at hollow site with a strong binding energy (−1.9 eV), inducing a semi-metal-to-metal transition. The material exhibits a high theoretical capacity (744 mAh/g), a moderate average voltage (0.78 V), and a low Li diffusion barrier (0.31 eV). KMC simulations further quantify the concentration and temperature dependent Li diffusivity, yielding the empirical relation $D_{Li}$($C_{Li}$,T) for Li concentrations in the range [0.01–0.1]. At room temperature, the calculated $D_{Li}$​ values span 2 × 10⁻⁹ to 5 × 10⁻⁸ cm²/s, showing excellent agreement with experimental data.