Poly(dithieno[3,2-b:2’,3’-d]pyrrole) twisting redox pendants enabling high current durability in all-organic proton battery

Abstract

Conducting polymers (CPs) bearing redox-active units are remarkable electrode materials for aqueous batteries. We report herein the elegant design of dithieno[3,2-b:2’,3’-d]pyrrole (DTP) twisted quinones repeating CPs for high-performance and robust all-organic proton battery in 1 M sulfuric acid electrolyte. The N-anthraquinone or naphthoquinone pendants act as superior redox sites by promoting electron transport along π-conjugated backbone via intermolecular charge transfer. The DTP-cored redox polymers exhibit high reversibility in charge/discharge cycling and withstand high current rate up to 50 C. The twist alignment of quinone pendants on DTP backbone facilitates charge transport and electrochemical reaction kinetics. By assembling two redox polymers with different energy levels as electrode pair, the all-polymer proton battery demonstrates a high capacity of 78 mAh g−1 (0.5 A g−1) and excellent rate capability (39 mAh g−1 at 20 A g−1). This proof-of-concept demonstration indicates we can develop more up-scalable, easily accessible, safe and environmentally benign organic electrodes for aqueous batteries through delicate materials design.