Scientists store energy in paper

Simply coating a sheet of paper with ink made of single-walled carbon nanotube (CNT) and silver nanowire films makes a highly conductive storage device, said Yi Cui, assistant professor of materials science and engineering at Stanford University.

The paper storage-device can last through 40,000 charge-discharge cycles - at least an order of magnitude more than lithium batteries.

The commercially available paper can be made highly conductive with a sheet resistance as low as one ohm per square (Ω/sq), and when only the mass of the CNTs are considered, a specific capacitance of 200F/g, a specific energy of 30-47Wh/kg, and a specific power of 200,000W/kg can be achieved.

Cui had previously created nanomaterial energy-storage devices using plastics. His new research shows that a paper storage-device is more durable because the ink adheres more strongly to paper.

A paper storage-device may be especially useful for applications such as electric or hybrid cars, which depend on the quick transfer of electricity.