Study on the Distribution of Polymeric Binder in Lib Composite Electrodes By Measuring Adhesion at Different Depths

Abstract

As the loading level or thickness of LIB composite electrodes increases, it becomes more difficult to uniformly distribute all components within the electrode. Because electric conductors are very small and light, they tend to rise upwards during drying process. Especially, to speed up the electrode fabrication process, not only drying temperature but also coating speed is maximized for reducing production costs. In this harsh condition, the polymeric binder tends to be unevenly distributed depending on the depth of electrode. Nevertheless, due to limited analysis tools, it had been left as research area to explore. Meanwhile, since a new tool, surface and interfacial cutting analysis system (SAICAS), was developed, the adhesion properties of the composite electrodes could be measured deliberately while changing the depth. Herein, we attempted to unveil the polymeric binder distribution by measuring the adhesion strength at different depths. In order to increase the reliability of the analytical results, composite electrode samples having different binder compositions and distributions were prepared and used for this study. At the same time, the compositional analysis with x-ray photoelectron spectroscopy were also conducted to confirm the binder distribution as a function of electrode depth. Finally, we investigated the effect of binder distribution on the electrochemical properties as well.