Synthesis and Evaluation of Bislawsone Derivatives as Possible Electrolytes for Redox Flow Batteries

Abstract

As climate change continues to be a global issue due to its negative environmental impact, various countries have made great efforts to integrate more renewable energy into the power-grid. Using renewable energy can lower dependency on fossil fuels but, there are issues that limit switching from consuming fossil fuels to renewable energy. In the case of solar or wind technology, the energy harnessed is not consistent throughout the day. By pairing renewable energy with redox flow batteries (RFBs), this can address the issue of inconsistent energy. Through RFBs, excess energy generated by renewable energy can be stored by electrochemical bonds. The focus of this research is to synthesize a water-soluble bislawsone to use as a redox active material for RFBs using 7-bromo-3,4-dihydro-2H-naphthalen-1-one. 2,2’-bis(3-hydroxy-7-methoxy-N,N,N-trimethylethanaminium chloride-1,4-naphthoquinone) was made but was not purified. The crude product was used in cyclic voltammetry (CV) testing. As a baseline, 5 mM of 7,7’-dibromo-2,2’-bis(3-hydroxy-1,4-naphthoquinone) was added to 1M KOH and the CV was measured. The potential was measured at -0.637 V. The electrolytic solution consisted of 5 mM of redox active material with 1M KCl in water adjusted to pH 7. There was no measurement. The second electrolytic solution consisted of 5 mM of redox active material with 1M KCl in 1M KOH. The potential was measured at -0.628 V. Solubility decreased by adding supporting salts and at pH 7. This suggests that adding a water-soluble group on bislawsone influences solubility and solubility affects voltage potential.