The ultimate electronic energy-storage device would store plenty of energy but also charge up rapidly and provide powerful bursts when needed. Sadly, today’s devices can only do one or the other: capacitors provide high power, while batteries offer high storage.
Now researchers at the University of Maryland have developed a kind of capacitor that brings these qualities together. The research is in its early stages, and the device will have to be scaled up to be practical, but initial results show that it can store 100 times more energy than previous devices of its kind. Ultimately, such devices could store surges of energy from renewable sources, like wind, and feed that energy to the electrical grid when needed. They could also power electric cars that recharge in the amount of time that it takes to fill a gas tank, instead of the six to eight hours that it takes them to recharge today.
There are many different kinds of batteries and capacitors, but in general, batteries can store large amounts of energy yet tend to charge up slowly and wear out quickly. Capacitors, meanwhile, have longer lifetimes and can rapidly discharge, but they store far less total energy. Electrochemists and engineers have been working to solve this energy-storage problem by boosting batteries’ power and increasing capacitors’ storage capacity.