Effect of Conductive Carbon Morphology on the Cycling Performance of Dry-Processed Cathode with High Mass Loading for Lithium-Ion Batteries

Abstract

The solvent-free dry processing of electrodes is highly desirable to reduce the manufacturing cost of lithium-ion batteries (LIBs) and increase the active mass loading in the electrode. The drying process is based on the fibrillation of the polytetrafluoroethylene binder induced by shear force. This technique offers the advantage of uniformly dispersing the active material and conductive carbon without binder migration, thereby facilitating the fabrication of thick electrode with high mass loading. In this study, we explored the influence of conductive carbon morphology on the cycling performance of dry-processed LiNi0.82Co0.10Mn0.08O2 (NCM) cathodes. In contrast to Super P, which provided electronic pathways through point-contact, the fibrous structure of the vapor-grown carbon fibers (VGCFs) promoted line-contact, ensuring long and less-torturous electronic pathways and enhanced utilization of active materials. Consequently, the cathode employing fibrous VGCFs achieved higher electrical conductivity, resulting in enhanced electrochemical performance. The dry-processed NCM cathode employing VGCF with an areal capacity of 8.5 mAh cm-2 delivered a high discharge capacity of 212 mAh g-1 with good capacity retention. X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were conducted to investigate the degradation behavior of the high-mass-loaded cathodes with two different conductive carbons.