Purpurin has been used for centuries as a natural dye.
Now, researchers at Rice University and the City College of New York have found that the plant extract also works as a natural cathode for lithium-ion batteries.
According to study lead Arava Leela Mohana Reddy, a research scientist at Rice, standard lithium-ion batteries aren't environmentally-friendly.
"They use cathodes of lithium cobalt oxide, which are very expensive. You have to mine the cobalt metal and manufacture the cathodes in a high-temperature environment ... and then there is the issue of recycling," he said in a statement.
Purpurin offers an environmentally-friendly alternative, because its production process is less energy intensive.
It can be manufactured in room temperature, and growing acres of madder plants to produce the batteries would remove carbon dioxide from the atmosphere.
An organic cathode would make the batteries non-toxic, making them easier to discard.
Scientists hope the product will be commercially available in a few years' time.
The findings were published earlier this week in Scientific Reports.