A Battery-Capacitor Hybridfor Hybrids

Lead-acid batteries are relics that haven't changed much since their invention nearly 150 years ago. Heavy and unable to withstand rapid charge-discharge cycles, they are unsuitable for the automotive world's killer app, hybrid-electric vehicles. Hybrids instead use expensive nickel-metal hydride (NiMH) batteries or, experimentally, lithium batteries. But a new, souped-up version of lead-acid batteries could change that, cutting the cost of hybrids and also improving the function of power grids and a range of other applications.