A new polymer jelly could be the next big step forward for lithium batteries. The jelly replaces the volatile and hazardous liquid electrolyte currently used in most lithium batteries. Researchers from the University of Leeds hope their development leads to smaller, cheaper and safer gadgets.Once on the market, the lithium jelly batteries could allow lighter laptop computers, and more efficient electric cars. In 2006, Dell recalled four million laptop batteries because of concerns that they might catch fire. Dell replaced them with batteries that used lower-performance electrodes, but these batteries were significantly larger. Battery size still dictates the size and weight of most laptops, say the developers of the new battery. Electronics manufacturer Apple got around the safety problem for their lightweight laptops with a solid polymer electrolyte, but in doing so, the power output of the computers suffered.Overheating is also an issue for electric cars. Developers have had to use reinforced, steel-clad battery housings, multiple fuses and circuits to protect the battery during charging. All of these contribute to the cost and weight, and hence efficiency, of electric cars.