In this project, funded by the Chemical Structure, Dynamics & Mechanisms-B Program of the Chemistry Division, Professor Christopher Bejger of the Department of Chemistry at the University of North Carolina at Charlotte is working with Professor Mitchell Anstey of Davidson College and Professor Todd Coolbaugh of Johnson C. Smith University to examine redox flow batteries (RFBs) for electrochemical energy storage. RFBs have emerged as capable electrochemical energy storage devices capable of compensating for the intermittent nature of renewable energy sources like wind and sun. Traditional RFBs rely on expensive metal-based materials and corrosive electrolytes. RFBs that comprise of organic molecules and operate at neutral pH are desirable from a cost and safety perspective. The research team is developing new RFB based on organic molecules (substituted radialene molecules) with reversible redox behavior in water. The project lies at the interface of organic synthesis, materials chemistry, and analytical electrochemistry, and is therefore well suited to the education of undergraduate scientists. The three-institution team will plan and fabricate an interactive exhibit on RFBs to expand awareness and engage the regional public regarding grid-scale renewable energy storage. Students involved in the research have the opportunity to work closely with faculty members at each institution and a regional industry partner. This project will reach a broad audience of students and adults alike during demonstrations at various outreach events and local schools with diverse student populations.
Radialenes are cross-conjugated organic molecules that support multielectron transfer and can often be isolated in various oxidation states. Several substituted [3]radialene dianions exhibit reversible electrochemistry and undergo steady galvanostatic cycling in neutral pH aqueous solutions. In this project, principles of molecular design will be used to logically tailor organic radialene-based derivatives for use in aqueous redox flow batteries (RFBs). RFB applications require stable, soluble, and high voltage active species as electrolytes, and the hexasubstituted [3]radialene scaffold can be assembled in a controllable, stepwise fashion to allow systematic tailoring to meet these specifications. A hierarchical synthetic approach will be used to tune the [3]radialene scaffold using various active methylene building blocks and zwitterionic radialene intermediates. Introduction of hydrophilic moieties will be used to enhance aqueous solubility. A predictive method based on Hammett substituent constants (?) will be derived to adjust oxidation potentials of the [3]radialene dianions with precision. The most promising conjugates that exhibit stability, high solubility, and favorable redox potential will be electrochemically characterized and used to prepare full cell RFB prototypes.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
