Science: To extend the driving range of electric cars, researchers have been working on a better battery. Now Peter Bruce and coworkers at the University of Saint Andrews in the UK report in Science that they’ve developed the first stable lithium–air battery. Such batteries have the desirable feature of high energy density, but their electrodes and electrolytes have turned out to be unstable. By replacing the usual carbon cathode with one made from inert gold nanoparticles and using the common conductive solvent DMSO as the electrolyte, the team succeeded in building a battery that was “stable for 100 charge and discharge cycles with only a 5% loss of power,” writes Robert Service for Science. Although gold is too heavy and too expensive to be used in a car battery, the team’s results show promise for future research.