Geometric and Electrochemical Characteristics of LiNi1/3Mn1/3Co1/3O2 Electrode with Different Calendering Conditions

•A synchrotron TXM tomography system was used to obtain morphology data of NMC electrodes.•Geometric and electrochemical characteristics of the electrodes were analyzed.•SEI and charge transfer resistances decrease with increasing NMC density.•Increasing calendering causes crashing of NMC particles and decrease rate capability.•Optimum performance is achieved at 3.0 g/cm3 NMC density.

The impact of calendering process on the geometric characteristics and electrochemical performance of LiNi1/3Mn1/3Co1/3O2 (NMC) electrode was investigated in this study. The geometric properties of NMC electrodes with different calendering conditions, such as porosity, pore size distribution, particle size distribution, specific surface area and tortuosity were calculated from the computed tomography data of the electrodes. A synchrotron transmission X-ray microscopy tomography system at the Advanced Photon Source of the Argonne National Laboratory was employed to obtain the tomography data. The geometric and electrochemical analysis show that calendering can increase the electrochemically active area, which improves rate capability. However, more calendering will result in crushing of NMC particles, which can reduce the electrode capacity at relatively high C rates. This study shows that the optimum electrochemical performance of NMC electrode at 94:3:3 weight ratio of NMC:binder:carbon black can be achieved by calendering to 3.0 g/cm3 NMC density.