Wouldn’t it be nice if your digital watch or cellphone quickly charged, without a battery to replace? How about solar panels with built-in energy storage? These things and more may soon become a reality thanks to a new form of ultracapacitor.

Technology Review reports that Professor Yury Gogotsi of Drexel University in Philadelphia and his team have created new, more powerful thin-film carbon ultracapacitors. Batteries utilize chemical reactions, but ultracapacitors use the transfer of surface charges to store and discharge energy. This makes them faster, gives them a lifespan of hundreds of thousands of cycles, and avoids the toxic materials often used in batteries. Until now ultracapacitors haven’t been used more widely because of limits on the amount of energy they can store and difficulties in scaling.

The new ultracapacitors are significant because they can store three times the energy of the same volume of conventional ultracapacitors and can be made into large films using standard chip-making techniques. If integrated directly into chips, they could also eliminate the need for external capacitors, lowering costs and improving performance. The films are thin enough that they might even work with flexible electronics. Y-Carbon, a Drexel spin-off company, is commercializing the technology.