The device, developed at Stanford University, produces 10 times the amount of electricity of existing lithium-ion batteries. A laptop that now runs on battery for two hours could operate for 20 hours, the university said Friday in a release.

Engineering professor Yi Cui said the lithium is stored in a forest of tiny silicon nanowires, each with a diameter one-thousandth the thickness of a sheet of paper. The nanowires inflate four times their normal size as they soak up lithium.

The findings were published online in the journal Nature Nanotechnology.

Cui said the expanded storage capacity could make Li-ion batteries attractive to electric car manufacturers. Cui suggested that they could also be used in homes or offices to store electricity generated by rooftop solar panels.