Before the age of the smartphone, mobile phone manufacturers were locked in an arms race to see who could create a smaller, but still usable device. Smartphones came along, and now the arms race is more or less focused on how big a screen can be while still being accepted by consumers. During this arms race, the way to keep phones from being unwieldy is to make them thin. Researchers have created a new supercapacitor so small that if it were used in smartphones, could make the devices even thinner and lighter than they are now.