'Double-duty' electrolyte enables new chemistry for longer-lived batteries

Apr 24, 2014
When Oak Ridge National Laboratory researchers incorporated a solid lithium thiophosphate electrolyte into a lithium-carbon fluoride battery, the device generated a 26 percent higher capacity than what would be its theoretical maximum if each component acted independently. Credit: Oak Ridge National Laboratory

(Phys.org) —Researchers at the Department of Energy's Oak Ridge National Laboratory have developed a new and unconventional battery chemistry aimed at producing batteries that last longer than previously thought possible.

In a study published in the Journal of the American Chemical Society, ORNL researchers challenged a long-held assumption that a battery's three main components—the positive cathode, negative anode and ion-conducting electrolyte—can play only one role in the device.

The electrolyte in the team's new battery design has dual functions: it serves not only as an ion conductor but also as a cathode supplement. This cooperative chemistry, enabled by the use of an ORNL-developed solid electrolyte, delivers an extra boost to the battery's capacity and extends the lifespan of the device.

"This bi-functional electrolyte revolutionizes the concept of conventional batteries and opens a new avenue for the design of batteries with unprecedented energy density," said ORNL's Chengdu Liang.

The team demonstrated the new concept in a lithium carbon fluoride battery, considered one of the best single-use batteries because of its high energy density, stability and long shelf life. When ORNL researchers incorporated a solid lithium thiophosphate electrolyte, the battery generated a 26 percent higher capacity than what would be its theoretical maximum if each component acted independently. The increase, explains Liang, is caused by the cooperative interactions between the electrolyte and cathode.

"As the battery discharges, it generates a lithium fluoride salt that further catalyzes the electrochemical activity of the electrolyte," Liang said. "This relationship converts the —conventionally an inactive component in capacity—to an active one."

The improvement in capacity could translate into years or even decades of extra life, depending on how the battery is engineered and used. Longer-lived disposable batteries are in demand for applications such as such as artificial cardiac pacemakers, radiofrequency identification devices, remote keyless system, and sensors, where replacing or recharging a battery is not possible or desirable.

"If you have a pacemaker, you don't want to undergo surgery every 10 years to replace the battery," Liang said. "What if a could last 30 to 50 years? Our fundamental research is opening up that possibility through a new design mechanism."

Explore further: A battery that 'breathes' could power next-gen electric vehicles

More information: "Pushing the Theoretical Limit of Li-CFx Batteries: A Tale of Bi-functional Electrolyte." pubs.acs.org/doi/full/10.1021/ja5026358

add to favorites email to friend print save as pdf

Related Stories

Study paves way for larger, safer lithium ion batteries

Jan 23, 2013

(Phys.org)—Looking toward improved batteries for charging electric cars and storing energy from renewable but intermittent solar and wind, scientists at Oak Ridge National Laboratory have developed the ...

Fluoride shuttle increases storage capacity

Oct 21, 2011

German researchers have developed a new concept for rechargeable batteries. Based on a fluoride shuttle -- the transfer of fluoride anions between the electrodes -- it promises to enhance the storage capacity ...

Recommended for you

Simulations for better transparent oxide layers

Sep 01, 2014

Touchscreens and solar cells rely on special oxide layers. However, errors in the layers' atomic structure impair not only their transparency, but also their conductivity. Using atomic models, Fraunhofer ...

Team pioneers strategy for creating new materials

Aug 29, 2014

Making something new is never easy. Scientists constantly theorize about new materials, but when the material is manufactured it doesn't always work as expected. To create a new strategy for designing materials, ...

Plug n' Play protein crystals

Aug 29, 2014

Almost a hundred years ago in 1929 Linus Pauling presented the famous Pauling's Rules to describe the principles governing the structure of complex ionic crystals. These rules essentially describe how the ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Xolin
not rated yet May 07, 2014
The statement,

"...a battery's three main components—the positive cathode, negative anode..."

is incorrect. A battery has a POSITIVE anode and a NEGATIVE cathode.