Polymeric binder distribution of lithium-ion battery (LIB) electrodes becomes as important as using high-capacity electrode materials for highly loaded electrodes. Because, the electrode coating layer can be delaminated from the current collector within the service time unless the binder is well-dispersed. However, due to the limitation of usable analysis tools, to get some information on binder distribution remains one of the unresolved issues in LIBs. Fortunately, we have started to analyse these issues using a new tool, surface and interfacial cutting analysis system (SAICAS, Daipla Witnes, Japan), to measure adhesion properties of LIB composite electrodes as a function of depths. The adhesion strength measured by SAICAS is approximately proportional to the binder content, the polymeric binder distribution within the electrodes can be unveiled with a SAICAS.

In this study, we fabricated two LiCoO₂ positive electrodes dried at different temperatures, 130 and 230^oC. They were used to analyse the polymeric binder distribution in the electrode by using SAICAS. First, their adhesion strengths were carefully measured at every 10 μm depth from the electrode surface. At the same time, both surface/cross-sectional SEM images and corresponding EDS atomic mapping were confirmed to find correlation with adhesion strength. Finally, their electrochemical property changes such as cycle life, rate capability, DC-IR, etc. at room and high temperatures were also discussed.