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

Abstract

The impact of calendering process on the geometric characteristics and electrochemical performance of LiNi 1/3 Mn 1/3 Co 1/3 O 2 (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/cm 3 NMC density.

Heated Calendering of Cathodes for Lithium‐Ion Batteries with Varied Carbon Black and Binder Contents

“…This has been reported for LCO at 3 C, for LFP at 10 C, and for LiMn 2 O 4 (LMO)/NCA hybrid cathodes with high mass loadings at 7.5 C . Another negative impact can be the presence of particle fracture at high compaction degrees, which is very prominent for LMO cathodes, but there are also indications for the particle fracture of NCM . Consequently, Kang et al proposed an optimal coating density of 3.0 g cm −3 for NCM cathodes, which is equivalent to a porosity of ≈35% (recalculated from given data).…”

Modelling of the Calendering Process of NMC‐622 Cathodes in Battery Production Analyzing Machine/Material–Process–Structure Correlations

“…The mechanical homogenization through calendering leads to a homogeneous aging of the cell and results in a lower standard deviation of the discharge capacities . This can be explained by lower inhomogeneities within the particle‐pore structure at higher densities . Calendering is also important to reduce product quality deviations in terms of C‐rate performance .…”

Three-Dimensional Reconstruction and Analysis of All-Solid Li-Ion Battery Electrode Using Synchrotron Transmission X-ray Microscopy Tomography

“…Figure 1e shows a representative reconstructed 2D slice image of 700 psi all-solid electrode. Compared to our previous X-ray CT images of liquid electrolyte electrodes, such as LCO and NMC [27][28] , the allsolid electrode has three phases to be distinguished. As shown in Figure 1e, the white phase is NMC, the gray phase is LTAP and the black phase includes both pore and 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 8 super-P carbon.…”

“…Tortuosity has been 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 considered as a function of porosity ( ) by Bruggeman relation = −0.5 . Evidence has indicated that Bruggeman relation underestimates tortuosity in LIB electrodes 21,[27][28] . Tortuosity in all-solid electrode cannot be calculated by Bruggeman relation because there are three phases in the electrode and Li ion transports through the solid LTAP phase.…”