Low‐Carbon Poly(3‐vinyl‐ N ‐methylphenothiazine) Electrode Formulation Using PEDOT:PSS (poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate)) for Lithium‐Based Energy Storage

Metal-free organic electrode materials are of increasing interest due to their environmental compatibility, natural abundance, and structural versatility. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is an intrinsically conductive polymeric salt that has emerged as a multifunctional electrode material, serving both as a conductive additive and as binder in energy storage applications. Organic electrode materials´ inherent low electronic conductivity often necessitates high loadings of conductive carbon additives, which diminishes the overall energy density. To overcome this challenge, PEDOT:PSS is investigated as a partial substitute for traditional conductive carbon in poly(3-vinyl-N-methylphenothiazine) (PVMPT) redox polymer electrodes. Remarkably, even with a high PVMPT content of 80 wt% and a reduced carbon content to 15 wt%, the composite electrode delivers a reversible capacity of 84 mAh g−1, which is ≈81% of that achieved with 50 wt% PVMPT and 45 wt% carbon black, over 250 cycles at 1C rate. Importantly, the fabrication process employs water-based processing with a carboxymethyl cellulose (CMC) binder, completely avoiding hazardous solvents such as N-methyl-2-pyrrolidone (NMP) and polyvinylidene difluoride (PVdF) binder. Overall, these results highlight the potential of PEDOT:PSS to enable low-carbon content, high-performance, and eco-friendly organic battery electrodes that align with the principles of sustainable energy storage.