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

It is important to understand the electrochemical performance as well as the influence of various cathode materials; LiMn₂O₄ and Li[Ni_0.6Co_0.2Mn_0.2]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[Ni_0.6Co_0.2Mn_0.2]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[Ni_0.6Co_0.2Mn_0.2]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[Ni_0.6Co_0.2Mn_0.2]O₂ but the specific energy of Li[Ni_0.6Co_0.2Mn_0.2]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[Ni_0.6Co_0.2Mn_0.2]O₂ but its cycle ability was drastically reduced while that of the Li[Ni_0.6Co_0.2Mn_0.2]O₂ was improved impressively.

References

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