One tough power source: Creating a lithium-ion battery that cannot catch fire

The popular myth that a spider is never more than a few feet away is arguably more true of lithium-ion batteries than of arachnids. Powering everything from smartphones and laptops to electronic cigarettes, lithium-ion batteries beat out alternative sources of power because of their top-notch energy density and long life cycle, meaning they can be recharged over and over again before breaking down. Yet for all these advantages, lithium-ion batteries come with a major concern: They can catastrophically ignite when they overheat.