INL RESEARCH & DEVELOPMENT

Lithium battery research 

at the INL 

Rechargeable lithium batteries 

havenʼt really lived up to their 

expectations. They run down 

when theyʼre not being used, 

they get old and stop taking charges, and they freeze 

if they get too cold. At the 

INEEL, chemists have signifi -

cantly improved the heart of 

lithium rechargeable batteries. 

These new batteries function 

at very low temperatures (as 

low as outer space), have a 

much longer shelf-life, and 

are safer than conventional 

batteries. 

At the heart of the matter

The centerpiece of INLʼs 

improved rechargeable battery 

is a solid battery electrolyte. 

Battery electrolytes provide 

ion transport and separate a 

batteryʼs positive and negative 

electrodes. Currently available electrolytes for standard 

and rechargeable batteries are 

fl ammable, physically leaky, 

or electrically leaky.

For example, the liquid 

electrolytes in conventional 

lithium batteries are fl ammable, causing them to explode 

upon recharging. The liquid 

and gel electrolytes now 

used in rechargeable lithium 

batteries provide a “leaky” 

electrical barrier because 

these materials conduct electricity as well as ions. So the 

electrical charge leaks directly 

between the electrodes, and 

as the battery sits it loses 

charge. Also, these materials 

form insulating deposits that 

Prototype rechargeable 

lithium battery.

Continued on next page

eventually destroy the battery. 

One-time-use lithium watch 

batteries use lithium metal as 

the power source. However, 

due to the limitations of conventional liquid electrolytes, 

they cannot be recharged 

without a real danger of fi re or 

explosion. Our solid technology has promise to solve that 

problem, allowing lithium 

metal systems to be recharged 

over and over.

A heart that remains true

The solid electrolyte developed by INL chemist Mason 

Harrup and his colleagues is 

a unique mixture of a gel-like 

polymer ceramic – properly 

mixing the polymer and ceramic creates a clear membrane. Harrup and his 

Advanced membranes produce longer 

lasting and safer batteries.
INL RESEARCH & DEVELOPMENT

David L. Miller

(208) 526-9052

David.Miller@inl.gov

Technical Contact:

Mason Harrup

(208) 526-1356

Mason.Harrup@inl.gov

Continued from front

Lithium ion (yellow sphere) is transported through the stabilized 

composite electrolyte material, which is formed from ceramic 

scaffolding (cubes) and polymer (ribbons). 

team found that the 

composite membrane, 

originally investigated by 

Eastman-Kodak for antistatic applications, could be 

sandwiched between two 

electrodes and act as an 

electrolyte. The membrane 

easily conducts positive 

ions but not electrical current, providing effective 

electrical insulation with 

virtually no electrical leak. 

Harrup has kept prototype 

batteries on the shelf for 

a year without having to 

recharge them. In addition, 

the all-solid design resists 

damage, which allows a 

battery to be recharged 

again and again.

This electrolyte also 

performs at temperature extremes where others donʼt. 

The membrane withstands 

high temperatures that 

degrade conventional electrolytes. And, unlike liquid 

or gel electrolytes that 

freeze, the solid continues 

to function down to -100 

degrees Fahrenheit, making 

it useful for space exploration. Satellite companies 

and NASA have expressed 

an interest in its development. INL researchers are 

continuing to improve the 

voltage output of the solid 

lithium cells.

For more information

INL is a U.S. Department of Energy 

national laboratory operated by 

Battelle Energy Alliance

04-GA50193-64