New York: Scientists including an Indian-origin researcher are developing an eco-friendly, lithium-ion battery from an ancient natural red plant dye that can power your cellphone.
The dye the researchers are investigating for use in batteries comes from the roots of a climbing herb known as the madder plant.
Civilisations in Asia and the Middle East first boiled madder roots more than 3,500 years ago to extract purpurin, a nontoxic dye they used to colour fabrics vivid oranges, reds and pinks, TechNewsDaily reported.
"This is a paradigm shift. For the last 3,000 years, we`ve used purpurin as a dye material we never thought this could be used in energy storage," said researcher George John, an organic chemist at the City College of New York.
"This is definitely exciting to us and maybe future generations," John told the website.
Most lithium-ion batteries rely on cobalt as a key ingredient in the electrodes that electric current flows through.
"Thirty percent of globally produced cobalt is fed into battery technology," said researcher Arava Leela Mohana Reddy, a materials scientist at Rice University.
However, mining cobalt is expensive, and supplies are finite. Fabricating and recycling lithium-ion batteries made with cobalt also demands high temperatures and lots of energy.
In 2010, almost 10 billion lithium-ion batteries had to be recycled, Reddy said.
Moreover, producing and recycling the batteries pumps an estimated 72 kg of the greenhouse gas carbon dioxide into the atmosphere for every kilowatt-hour of energy in the batteries.
After investigating a number of molecules from nature, the researchers found that purpurin and its relatives seem ideal as electrode materials.
For instance, purpurin has electron-rich molecular rings adept at passing electrons back and forth just as traditional electrodes do, easily coordinating with lithium.
In addition, the researchers found they could make purpurin into an electrode in only a few easy steps, all relatively cheap at room temperature ? they simply dissolved the dye in an alcohol solvent and added lithium salt.
When the salt`s lithium ion binds with purpurin, the solution turns from reddish yellow to pink.
Furthermore, growing madder would soak up carbon dioxide, not generate the global warming gas. The way purpurin binds to lithium renders it nontoxic as well, which suggests lithium-ion batteries made with it could just be thrown away without the need for costly recycling.
Researchers claimed the electrical performance of the battery they devised using purpurin "is within the ballpark of most conventional lithium-ion batteries".
The study was published in the journal Scientific Reports.