Lithium-ion batteries have shown huge increases in their capacity when silicon crushed into powder is used in them, researchers at Rice University in Houston say.

The result could lead to longer-lasting, cheaper rechargeable batteries, aimed especially at electric cars.

The report from researchers Sibani Lisa Biswal and research scientist Madhuri Thakur was published today in Nature.com's journal Scientific Reports.

Their methods have achieved 600 charge-discharge cycles at 1,000 milliamp hours per gram (mAh/g) using silicon anodes — a jump from the current 350 mAh/g capacity of existing graphite anodes.

"That puts it squarely in the realm of next-generation battery technology competing to lower the cost and extend the range of electric vehicles," said a release from the university.

mi-car-lithium-ion-300

Capacities are in the realm of next-generation battery technology competing to lower the cost and extend the range of electric vehicles. (Reuters)

10 times more ions

Strategies to make silicon more suitable for use in batteries have had mixed successes in the past.

Silicon can hold 10 times more lithium ions than the graphite anodes currently in use, but because it more than triples its volume during the charging phase, the swelling and shrinking causes silicon to quickly break down.

"We previously reported on making porous silicon films," said Biswal, an assistant professor of chemical and biomolecular engineering.

"We have been looking to move away from the film geometry to something that can be easily transferred into the current battery manufacturing process."

Far more surface

This time, she said, "Madhuri crushed the porous silicon film to form porous silicon particulates, a powder that can be easily adopted by battery manufacturers."

By crushing the sponges into porous grains, the researchers were able to create far more surface area to soak up lithium ions.

The research was partly funded by Lockheed Martin. Co-authors were Steven Sinsabaugh, a Lockheed Martin Fellow, and Lockheed Martin researcher Mark Isaacson.

"We're truly excited about this breakthrough and are looking forward to transitioning this technology to the commercial marketplace," Sinsabaugh said in a release.