Comparative Study on Experiment and Simulation of Blended Active Cathode Material for Lithium Ion Batteries Using COMSOL^TM Multiphysics 4.3b

Abstract

It is important to understand the electrochemical performance as well as the influence of various cathode materials; LiMn2O4 and Li[Ni0.6Co0.2Mn0.2]O2, on each other when mixed together as a single positive electrode for lithium ion batteries. In view of this, we used a previously developed lithium ion mathematical model for treating multiple active material to examine the electrochemical characteristics of the blended LiMn2O4 and Li[Ni0.6Co0.2Mn0.2]O2 active materials. The simulated results obtained using COMSOL multiphysics 4.3b were compared to the experimental results from coin cells built with the two positive electrode materials (composition based on LiMn2O4 and Li[Ni0.6Co0.2Mn0.2]O2) mixed in three different ratios and graphite as the negative electrode material. We also modeled the capacity fade effects on LiMn2O4 graphite cell based on the SEI formation at the negative electrode material and the particle dissolution of LiMn2O4 simultaneously to account for the behavior of the cell. There is a good agreement between the simulated results and the experimental results with slight deviations at higher C-rates. We observed from our experiment that, at high powers, the specific energy obtained from the electrode made of only LiMn2O4 exceeds that obtained from the electrode made of only Li[Ni0.6Co0.2Mn0.2]O2 but the specific energy of Li[Ni0.6Co0.2Mn0.2]O2 also exceeds that of LiMn2O4 at low powers. It was also observed that, the initial discharge capacity of LiMn2O4 is greatly enhanced due to the presence of the Li[Ni0.6Co0.2Mn0.2]O2 but its cycle ability was drastically reduced while that of the Li[Ni0.6Co0.2Mn0.2]O2 was improved impressively. References [1] P. Albertus, J. Christensen J. Newman, J. Electrochemical Society, 156 (7) (2009) A606-A618 [2] Jorge Vazquez-Arenas, Michael Fowler, Xiaofeng Mao, Shih-ken Chen, Journal of Power Sources , 215 (2012) 28-35