Renewable-lawsone-based sustainable and high-voltage aqueous flow battery

Recently, redox-flow batteries (RFBs) are drawing intensive attention due to their advantages of peak shaving, grid flexibility and long life time. All-vanadium RFBs are most widely employed, but the high cost and toxicity hinder their large-scale applications. As potential substitutes, development of organic-based aqueous RFBs is impeded by a lack of electroactive pairs with combination of high cell voltage and sufficient cycle stability. In this work, a novel biomolecule-based aqueous RFB with high performance was successfully fabricated. Lawsone, a renewable biomolecule derived from natural henna, was developed as a stable anolyte. By paring with 4-HO-TEMPO, the as-assembled RFB exhibits a high operating voltage above 1.30 V, which is among the highest records. Meanwhile, the capacity retention rate reaches 99.992% per cycle. This work highlights the rational utilization of redox-active biomolecule to construct sustainable, low-cost and high-performance aqueous RFBs.