Fully Aqueous‐Processed Li‐Ion Electrodes with Ultra‐High Loading and Potential for Roll‐to‐Roll Processing

In this study, high- and ultra-high-loading NMC622-based cathodes (7.0 and 18.0 mAh/cm2) and graphite-based anodes (9.0 and 22.5 mAh/cm2) were prepared by using a porous carbon structure as current collector. All electrodes in this work were prepared by an NMP-free, PFAS-free and scalable process. Full cells with areal capacities of 7 mAh/cm2 and 18 mAh/cm2 were assembled and tested. The results show an excellent cycling stability, reaching up to 950 cycles at 10 mA/cm2 for the cells with ultra-high-loading electrodes (capacity 18 mAh/cm2) and 650 cycles at 8 mA/cm2 for the cells with high-loading electrodes (capacity of 7 mAh/cm2). The influence of cathode porosity on the electrochemical performance in cells capacity of 7 mAh/cm2 showed that a lower porosity leads to a poorer rate capability as well as a worse cycling capability (400 cycles at 6 mA/cm2). Post-mortem analysis reveal that the anode aging is more pronounced during full cell cycling. Further the scalability of the production process was demonstrated by using a padder tool. With that, cathodes with a loading of 5 mAh/cm2 were produced in a roll-to-roll process.