A Comprehensive Studies on the Performance of a LiNi_0.6Mn_0.2Co_0.2O₂ Cathode Using a Physics-Based Model

Abstract

The gradual growth of the Li metal anode in lithium-ion batteries (LIBs) due to their high theoretical energy density has made it become the future of the battery fraternity replacing graphite anode. Notwithstanding, the cathode material, layered lithium transition metal oxides (particularly NMC – LiNixCoyMnzO2), plays an important role because of it’s potential to improve the overall energy density, lifetime and safety of the cell. For this reason, we present physics-based models developed with COMSOL Multiphysics that describe the effect of the structural properties of the positive electrode, which is LiNi0.6Mn0.2Co0.2O2 (NMC 622), on the performance of the Li metal cell. The models include charge conservation in the solid and electrolyte phase, mass conservation in the solid phase and electrolyte phase and the electrochemical kinetics generated at the interfaces between the solid phase and the electrolyte. The results from the models are validated with experimental data and there was a good agreement between them. The validated models are then employed to investigate the effects of particle size and porosity of the NMC 622 on the performance of the Li metal battery. The understanding of this study can be employed to potentially predict optimized structural parameters for Li metal battery depending on the desired applications.