Investigating the\nInfluence of Different Aprotic Processing\nSolvents for the PVdF Binder\non the Microstructure and Electrochemical Performance of High-Load\nPositive Electrodes for Lithium Ion Batteries

State-of-the-art manufacturing of positive electrodes\nin lithium\nion batteries is carried out in <i>N</i>-methyl-2-pyrrolidone\n(NMP), an aprotic organic solvent which stands out for good wetting\nproperties, a high boiling point allowing controlled evaporation during\nelectrode drying, and dissolving properties, for the conventionally\nused polymeric binder polyvinylidene difluoride. The replacement of\nNMP with nonhazardous, alternative solvents was proven to be difficult\nin terms of binder solubility. Furthermore, the inevitable energy-demanding\nrecovery of NMP due to safety concerns and environmental impact amounts\nfor noteworthy costs during electrode manufacturing. Here, the use\nof dimethyl sulfoxide (DMSO), γ-valerolactone (GVL), and dihydrolevoglucosenone\n(Cyrene) as possible alternative solvents to replace NMP in the production\nof positive electrodes based on LiNi<sub>0.6</sub>Mn<sub>0.2</sub>Co<sub>0.2</sub>O<sub>2</sub> with a high active material mass loading\nis presented. Homogeneous electrodes were produced and thoroughly\nexamined regarding adhesion strength, electronic conductivity, microstructure,\npossible solvent residues after drying, and electrochemical performance.\nIt was shown that DMSO and GVL are hopeful candidates to replace NMP\nwith DMSO being the superior alternative with similar performance\nresults compared to electrodes produced with NMP. The comparison of\ndifferent aprotic solvents reveals that a replacement of NMP with\nDMSO could be a step toward a greener, more sustainable electrode\nproduction.