Conjugated Polyimidazole Nanoparticles as Biodegradable Electrode Materials for Organic Batteries

Conjugated polymers are promising active materials for batteries. Batteries not only need to have high energy density but should also combine safe handling with recyclability or biodegradability after reaching their end-of-life. Here, π-conjugated polyimidazole particles are developed, which are prepared using atom economic direct arylation adapted to a dispersion polymerization protocol. The synthesis yields polyimidazole nanoparticles of tunable size and narrow dispersity. In addition, the degree of crosslinking of the polymer particles can be controlled. It is demonstrated that the polyimidazole nanoparticles can be processed together with carbon black and biodegradable carboxymethyl cellulose binder as an active material for organic battery electrodes. Electrochemical characterization shows that a higher degree of crosslinking significantly improves the electrochemical performance and leads to clearer oxidation and reduction signals of the polymer. Polyimidazole as part of the composite electrode shows complete degradation by exposure to composting bacteria over the course of 72 h.