The Economist on a promising new development in battery technology:
LITHIUM-ION batteries are hot stuff. Affordable, relatively lightweight and packing a lot of energy, they are the power source of choice for everything from mobile phones to electric cars. Unfortunately, the heat can be more than figurative. Occasionally, such batteries suffer malfunctions that lead to smoke, flames and even explosions. In gadgets, such meltdowns can be distressing and dangerous. In aircraft, they can be fatal. Earlier this year airlines grounded their entire fleet of Boeing’s next-generation 787 passenger jet after the lithium-ion batteries installed in two planes caught fire. Last month they have been permitted back in the air after being retrofitted with a protection system in the form of a tough steel box that vents directly outside in the event of a fire.
A more comforting solution, of course, would be to build a lithium-ion battery that could not burst into flames in the first place. Katie Zhong at Washington State University might have just such a device. For the last few years, she has been working on battery technology for flexible and bendable electronic gadgets. By blending a polymer called polyethylene oxide (PEO) with natural soy protein, she had made a solid electrolyte for lithium ion batteries that could be bent or stretched to twice its normal size without affecting its performance.
Like all batteries, lithium-ion rechargeables consist of two electrodes separated by an electrolyte. In a typical lithium-ion cell, the electrolyte is a solution of lithium salts and organic solvents. Charging drives lithium ions from the electrolyte into a graphite anode. On discharge, the reverse happens, with a balancing flow of electrons through the device being powered.
