Rose madder – a natural plant dye once prized throughout the Old World to make fiery red textiles – has found a second life as the basis for a new "green" battery.
Chemists from The City College of New York teamed with researchers from Rice University and the U.S. Army Research Laboratory to develop a non-toxic and sustainable lithium-ion battery powered by purpurin, a dye extracted from the roots of the madder plant (Rubia species).