Orbital-dependent redox potential regulation of quinone derivatives for electrical energy storage

Electrical energy storage in redox flow batteries has received increasing attention. Redox flow batteries using organic compounds, especially quinone-based molecules, as active materials are of particular interest owing to the material sustainability, tailorable redox properties, and environmental friendliness of quinones and their derivatives. In this report, various quinone derivatives were investigated to determine their suitability for applications in organic RFBs. Moreover, the redox potential could be internally regulated through the tuning of σ and π bonding contribution at the redox-active sites. Furthermore, the binding geometry of some selected quinone derivatives with metal cations was studied. These studies provide an alternative strategy to identify and design new quinone molecules with suitable redox potentials for electrical energy storage in organic RFBs.