PEDOT:PSS as a conductive polymer binder for ecologically and economically sustainable, carbon-free NMC electrodes

In this work new dispersion medium for positive electrode slurries for lithium-ion batteries, dimethyl sulfoxide (DMSO), is proposed, in combination with PEDOT:PSS conductive polymer as a binder. Dispersion of PEDOT:PSS in concentration of 2.5% w/w with anhydrous DMSO is prepared. The electrodes were prepared with NMC622 active material and prepared PEDOT:PSS/DMSO dispersion with and without addition of conductive carbon. SEM imaging with EDS mapping confirms creation of binding film of the polymer on grains of active material. Chronopotentiometry tests of the electrodes in half-cell lithium-ion setup reveal that the best electrochemical performance was achieved for 97.5% active material and 2.5% PEDOT:PSS without conductive carbon addition (ca. 170 mAh g⁻¹ at 0.1 C, 90% retention after 51 cycles). PEDOT:PSS enabled the elimination of the conductive carbon additive from the electrode and reduction of the binder content. It resulted in enhancement of the capacity per gram of electrode paste by approximately 17% compared with standard electrode composition.