How batteries grow old: Researchers build facility to put hybrid car batteries to the test

Oct 20, 2010

In a laboratory at Ohio State University, an ongoing experiment is studying why batteries lose their ability to hold a charge as they age -- specifically lithium-ion batteries, which have generated a lot of buzz for their potential to power the electric cars of the future.

Preliminary results presented today at the AVS 57th International Symposium & Exhibition, taking place this week at the Albuquerque Convention Center in New Mexico, suggest that the irreversible changes inside a dead battery start at the nanoscale.

Yann Guezennec and Giorgio Rizzoni of OSU developed new experimental facilities and procedures to charge and discharge commercially-available Li-ion batteries thousands of times over many months in a variety of conditions designed to mimic how these batteries are actually used by hybrid and all-electric vehicles. Some of the batteries were run in hot temperatures like those in Arizona; others in colder conditions similar to those in Alaska.

To understand the results of this testing, Bharat Bhushan, Suresh Babu, and Lei Raymond Cao studied the materials inside of the batteries to help determine how this aging manifests itself in the structure of the electrode materials.

When the batteries died, the scientists dissected them and used a technique called infrared thermal imaging to search for problem areas in each electrode, a 1.5-meter-long strip of metal tape coated with oxide and rolled up like a jelly roll. They then took a closer look at these problem areas using a variety of techniques with different length scale resolutions (e.g. scanning electron microscopy, atomic force microscope, scanning spreading resistance microscopy, Kelvin probe microscopy, transmission electron microscopy) and discovered that the finely-structured nanomaterials on these electrodes that allow the battery rapidly charge and discharge had coarsened in size.

Additional studies of the aged batteries, using neutron depth profiling, revealed that a fraction of the lithium that is responsible, in ion form, for shuttling electric charge between electrodes during charging and discharging, was no longer available for charge transfer, but was irreversibly lost from the cathode to the anode.

"We can clearly see that an aged sample versus and unaged sample has much lower lithium concentration in the cathode," said Rizzoni, director of the Center for Automotive Research at OSU. "It has essentially combined with anode material in an irreversible way."

This research is being performed by Center for Automotive Research at OSU in collaboration with Oak Ridge National Laboratory and the National Institute of Standards Technology.

The researchers suspect, but cannot yet prove, that the coarsening of the cathode may be behind this loss of lithium. If this theory turns out to be correct, it could point battery manufacturers in the right direction for making durable batteries with longer lifetimes.

Explore further: New approach to form non-equilibrium structures

More information: The presentation, "Multi-scale Characterization Studies of Li-ion Batteries" is at 6:00 p.m. on Tuesday, October 19, 2010. ABSTRACT: www.avssymposium.org/Open/Sear… PaperNumber=AS-TuP-9

Provided by American Institute of Physics

not rated yet
add to favorites email to friend print save as pdf

Related Stories

Scientists Working Toward Better Batteries

Mar 09, 2006

As more and more people rely on cell phones, laptop computers, personal organizers, and even hybrid electric-gas vehicles, scientists are working to develop rechargeable batteries that are ever smaller, cheaper, ...

Increasing Electric Car Battery Performance

Sep 23, 2009

(PhysOrg.com) -- Researchers have found that by replacing conventional graphite electrodes with silicon nanotube electrodes, lithium-ion batteries can store 10 times more charge.

New Hitachi Li-ion batteries to last ten years

Apr 09, 2010

(PhysOrg.com) -- Hitachi has announced they may be able to double the life of rechargeable lithium-ion (Li-ion) batteries through the development of a new cathode material. The material was developed in conjunction ...

Recommended for you

New approach to form non-equilibrium structures

11 hours ago

Although most natural and synthetic processes prefer to settle into equilibrium—a state of unchanging balance without potential or energy—it is within the realm of non-equilibrium conditions where new possibilities lie. ...

Nike krypton laser achieves spot in Guinness World Records

13 hours ago

A set of experiments conducted on the Nike krypton fluoride (KrF) laser at the U.S. Naval Research Laboratory (NRL) nearly five years ago has, at long last, earned the coveted Guinness World Records title for achieving "Highest ...

Chemist develops X-ray vision for quality assurance

17 hours ago

It is seldom sufficient to read the declaration of contents if you need to know precisely what substances a product contains. In fact, to do this you need to be a highly skilled chemist or to have genuine ...

The future of ultrashort laser pulses

18 hours ago

Rapid advances in techniques for the creation of ultra-short laser pulses promise to boost our knowledge of electron motions to an unprecedented level.

IHEP in China has ambitions for Higgs factory

Jul 23, 2014

Who will lay claim to having the world's largest particle smasher?. Could China become the collider capital of the world? Questions tease answers, following a news story in Nature on Tuesday. Proposals for ...

User comments : 0