Quinone-Enriched Polymer with a Large π-Conjugated Structure for High-Energy Supercapacitors: Synthesis and Electrochemical Assessment

Organic synthesis strategies can be used to form particular functional groups and skeleton structures of electrochemically active organic molecules with a reversible faradaic charge transfer suitable for high-efficiency energy storage. In this work, an organic molecular electrode (OME) is assembled by a unique combination of quinone-enriched polymers (PDAQs) with reduced graphene oxides (rGOs) for supercapacitors. Using 1,3,5-benzenetricarboxaldehyde (BA) as a bridge, electrochemically active 2,6-diaminoanthraquinone (DAQ) is connected in an imine linkage to create a novel polymer (PDAQ) with a unique structure. Excellent electrochemical characteristics are achieved as a result of an extensive π-conjugation system and high density of C═O in the structural unit of the PDAQ, while robust π–π interactions between PDAQ and rGO improve cycling stability. PDAQ/rGO-0.3 exhibits an impressive specific capacitance up to 622 F g–1 at 5 mV s–1 with exceptional capacitance retentions (87.8% at 100 mV s–1) and a long cycle life. To validate the practical energy storage capability of PDAQ/rGO-0.3, an asymmetric supercapacitor (ASC) was constructed utilizing 2,5-dihydroxy-1,4-benzoquinone-functionalized rGO (DBQ/rGO) as the positive electrode. The assembled ASC (PDAQ/rGO-0.3//DBQ/rGO) exhibits a remarkable energy density of 32.97 Wh kg–1 at a power density of 605.57 W kg–1 and maintains 88% after undergoing 10 000 cycles. The two ASCs were arranged in tandem configuration, effectively powering up to 63 light-emitting diodes (LEDs), demonstrating their prospective potential for energy storage applications.