If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.


Energy Storage

Thin-film battery breaks energy storage record

Careful manufacturing yields a lithium-ion battery for compact medical devices

by Katherine Bourzac
January 3, 2020 | A version of this story appeared in Volume 98, Issue 1


Photo of an individual thin-film battery on a penny.
Credit: CEA-Leti
A thin-film battery is shown on a penny for scale. The penny sits on a silicon die patterned with the batteries.

A tiny new battery that packs an energy punch could power more compact next-gen pacemakers and other medical devices. The LiCoO2 battery was developed by researchers at CEA-Leti, part of the French atomic energy agency. Battery chemist Sami Oukassi says it has a higher energy density than any thin-film battery reported so far. The battery is just 3.10 by 1.70 mm in area—which doesn’t leave much room for energy-storing electrode materials. Oukassi says his group improved the thin-film battery’s performance by making a thicker layer of LiCoO2 at higher yield. Thin-film batteries generally use less than 10 µm of the material; the CEA-Leti group was able to double this value while still achieving good-quality films that provide an easy path for charge-carrying lithium ions. “We developed advanced patterning methods for this material—usually you can’t do that on lithium,” Oukassi says. That enabled the team to make a prototype battery that meets the energy requirements for prototype medical devices such as disease-monitoring smart contact lenses. Oukassi, who described the research at the International Electron Devices Meeting in San Francisco in December, says the group hopes to encapsulate the battery so that it is safe for use in future wearable and implantable medical devices.


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.