Scientists have been figuring out how to develop eco-friendly ways of recharging batteries for years, from harvesting temperature fluctuations to harnessing your fidgets. But perhaps a better solution is to create a different kind of battery altogether; one that uses greener sources instead of finite ingredients like cobalt. That's exactly what the whiz-kids from the City College of New York, Rice University and the US Army Research Laboratory have done with a new lithium-ion battery powered by red dye extracted from madder roots.

Called rose madder or purpurin, the dye was apparently used in ancient civilizations for dying fabrics in oranges, reds and pinks. Fortunately for the future of the battery, it turns out its color molecules are also carriers of carbonyl and hydroxyl groups that make it ripe for use as an electrode and that purpurin is far easier to process than other organic materials: "These aromatic systems are electron-rich molecules that easily coordinate with lithium," said CCNY Professor George John. It'll likely take years before we'll get to the point of mass production of these things, but in the future we could finally say that batteries do indeed grow from trees.