Researchers at Saint Louis University in the States have developed a fuel cell battery that runs on sugar from virtually any source – soft drinks to tree sap. The new battery could eventually replace lithium ion batteries in many applications, including phones; it has the potential to operate three to four times longer on a single charge, for a start, and it’s also biodegradable. An early implementation might be a portable charger, using replaceable cartridges pre-filled with a sugar solution.