Currently, slurry coating is used in the manufacturing process of various products such as electrode films for batteries, electronic materials, and optical materials. However, it is well known that the distribution of material composition in the electrode film has a significant impact on the performance of the device. A slurry is a mixture of powders, binders, and additives dispersed in a liquid, and when this mixture is coated and deposited, the mixed materials are randomly distributed. Furthermore, in the process of drying and removing the dispersant, the binder moves with the dispersant and segregates, while the particulate additives tend to aggregate. Segregation of the binder and agglomeration of the conductive agents may result in poor battery characteristics. To solve these problems, we thought it would be effective to make the base material and the additive material bonded together to form composite particles.
NCM-PEI-GO composite particles were synthesized by forming an ionic complex consisting of polyethyleneimine (PEI) and graphene oxide (GO) on the surface of lithium transition metal oxide (NCM), a cathode active material. In this study, composite particles were synthesized by adding different amounts of PEI and GO, and the effect of the amount of PEI added on the size and thickness of the ionic complexes and the aggregation state of the composite particles was investigated, and the effect of the amount of GO added on the conductivity was discussed. The amount of GO added had no effect on the thickness of the ionic complexes, but had a significant effect on the aggregation of the composite particles.
The conductivity of the NCM-PEI-GO composite particles increased with increasing GO content. This may be due not only to the increase of conductive graphene species in the electrode film, but also to the enhanced conductive path due to the linkage and aggregation of composite particles by ionic complexes.