Driving change by using new materials in rechargeable batteries

Author: Nina Welding

Schaefer Battery Tw

Electric vehicles have been on the roads since 1999. Since that time, nearly 5.4 million hybrid and plug-in models have been sold. The lithium-ion batteries that run them offer high energy density and low maintenance, allowing a vehicle to travel hundreds of miles on one charge.

These power cells — which also drive power supplies, solar power storage, surveillance systems, electric wheelchairs, portable power packs and cellphones — have been the top choice for rechargeable batteries for more than a decade.

Lithium-ion batteries power the modern world, yet they have drawbacks. They are easy to overcharge, which results in overheating and can cause fires; have a limited lifespan; and cost up to 40 percent more than nickel cadmium batteries.

While some researchers are working to develop improved lithium-ion batteries, Jennifer Schaefer, associate professor of chemical and biomolecular engineering, is developing new alternatives for rechargeable batteries.

Her National Science Foundation funded project, “Engineering All-Solid Metal-Sulfur Batteries: Transport, Speciation, and Kinetics in Sulfur Copolymer Composite Cathodes,” explores the fundamental knowledge needed to develop new batteries based on sustainable materials that offer improved safety and lighter weight.

“The energy density of metal-sulfur batteries, such as magnesium-sulfur, can exceed that of lithium-ion batteries,” said Schaefer. “However, it is difficult to engineer them at the low electrolyte-to-sulfur ratios necessary to achieve that high performance.”

She and her team are creating a polymer (plastic) electrolyte and cathode so the new metal-sulfur battery would weigh less, take up less space and need to be charged less frequently. It would also be safer, as the polymer is not as flammable as the liquids used in today’s lithium-ion cells.

Additionally, said Schaefer, sulfur is readily available around the world, unlike the transition metals used in lithium-ion batteries, so the new battery would cost less to produce.

Schaefer works with her team of graduate and undergraduate students. The project also will include visiting undergraduate researchers from Xavier University of Louisiana.

Their work is supported through Electrochemical Systems, a program in the National Science Foundation’s Division of Chemical, Bioengineering, Environmental and Transport Systems.

Originally published by the College of Engineering on July 19.