CMC Staining Method for the Visualization of the Binder Distribution in Water-Based Electrodes with EDS

High Resolution Image Download MS PowerPoint Slide The selective staining of cellulose materials is crucial for the accurate investigation of the binder distribution in electrodes of lithium-ion batteries. This paper investigates how (heptadecafluorodecyl)trimethoxysilane selectively reveals the binder distribution via EDS. Selectivity was granted by investigating individual electrode components: graphite, carbon black (CB), styrene–butadiene rubber (SBR), and sodium carboxymethyl cellulose (NaCMC). Each component was treated with the staining agent, stored at 60 °C for 16 h, washed with ethanol, and analyzed via energy dispersive spectroscopy (EDS). Only NaCMC shows a significant increase in fluorine concentration, proving selective staining. The study further explores the reaction mechanism by varying the degree of substitution (DS) of NaCMC, showing a correlation between carboxyl moieties and fluorine concentration and identifies 16 h of heated storage as a viable staining condition. Finally, the method’s applicability was demonstrated by comparing binder distribution in electrodes dried at different rates, revealing the NaCMC binder distribution via EDS.