Cyrene─An Alternative Processing Solvent for <i>N</i>-Methyl-2-pyrrolidone in the Electrode Processing of Polyvinylphenothiazine Positive Electrodes for Lithium-Organic Batteries

N-methyl-2-pyrrolidone (NMP) is the state-of-the-art solvent used for processing positive electrodes during lithium ion battery (LIB) manufacturing. However, growing concerns regarding its toxicological profile, energy-intensive recovery process, and petrochemical origin have increased interest in alternative eco-friendly processing methods. Despite the development of potential alternatives, a suitable nonaqueous solvent that can replicate the performance of NMP while being more environmentally sustainable has yet to be fully realized, particularly in the context of electrode fabrication of organic electrodes. This study aims to evaluate the performance of the bioderived processing solvent Cyrene as an alternative to NMP for the fabrication of poly(3-vinyl-N-methylphenothiazine) (PVMPT)-based positive electrodes in lithium-organic batteries. Cyrene was used to dissolve the conventional polymeric binder polyvinylidene difluoride (PVdF) at temperatures above 80 °C, as it does not dissolve PVDF at room temperature (RT). The electrode paste was prepared at 100 °C, and the resulting electrodes, dried at two different temperatures, were evaluated for their electrochemical performance. The Cyrene-processed electrodes dried at higher temperature exhibited a discharge specific capacity of 93 mAh g–1 over 200 cycles, which corresponds to 83% of the theoretical specific capacity (112 mAh g–1). The capacity retention was comparable to that of the NMP-processed systems. This study demonstrates that Cyrene can serve as a viable and sustainable alternative processing solvent for organic battery electrodes, offering comparable electrochemical performance to NMP-processed systems and contributing to the sustainability of organic batteries.