Electrochemistry: Paper Li-ion Batteries Offer Flexible Power Options

Ultrathin rechargeable lithium-ion batteries have been fabricated on a single sheet of paper, resulting in extremely versatile and lightweight portable power sources, according to a study published in ACS Nano by Stanford University researchers (DOI: 10.1021/nn1018158). The advance might present an integrated energy solution for the developing field of paper-based electronics and lead to applications in “smart” packaging and radio-frequency sensing.

To make the batteries, Stanford materials scientists Liangbing Hu, Hui Wu, Yi Cui, and coworkers coated a solid help with a thin film of carbon nanotubes and deposited a film of a metal-containing lithium compound on top of the nanotubes. Then the team deposited the double-layer films on both sides of ordinary paper. In that design, the lithium layers function as battery electrodes and the nanotube films serve as current collectors. The paper is the electrode separator and also serves as a mechanical support.

The new batteries, which are just 300 μm thick, are thinner and extra flexible, and they exhibit higher vitality density and other electrical benefits, compared with other varieties of thin batteries, the scientists say. They add that battery performance did not degrade over the course of a 300-cycle recharging test.

Juxtaposing carbon nanotubes and lithium compounds with paper has enabled the group to optimize the device in an ultrathin architecture, says Rice University’s Pulickel M. Ajayan. “Such simple fabrication methods could prove helpful for integrating other nanomaterials for building the next generation of energy-storage devices,” he says.