Systematic Comparison of Rapid Charging Performance and Impedance Characteristics of Lithium‐Ion Batteries Using LiCoO ₂ , LiNi ₁ / ₃ Mn ₁ / ₃ Co ₁ / ₃ O ₂ , and LiFePO ₄ as Positive Electrode Materials

The selection and operational optimization of lithium‐ion batteries (LIBs) is an important issue in the fields of electrified mobility and renewable energy. The present study assessed the charging performance of LIBs incorporating LiCoO 2 (LCO), LiNi 1/3 Mn 1/3 Co 1/3 O 2 (NMC), and LiFePO 4 (LFP) as active materials in the positive electrode. Cells were assembled having identical components other than the positive electrode, and the charging capacity and charging energy of each were compared using a power‐control technique. Based on impedance data obtained from full cells and single electrodes, equivalent‐circuit simulations and theoretical examinations based on the Butler–Volmer equation, electronic resistance ( R el ), solid electrolyte interphase layer resistance ( R sei ) and charge transfer resistance ( R ct ) values were obtained. The loss factors determining rapid charging performance were also theoretically examined. At low loads, the LCO and NMC electrodes providing high open‐circuit potentials exhibited better charging energy characteristics. In contrast, at high loads, the LFP electrode exhibited smaller losses and so showed superior performance. During rapid charging, the performance characteristics of the LCO and NMC electrodes were limited by R ct and R el , respectively, whereas the LFP electrode maintained low R ct and R el values and so showed the best loss characteristics.