Battery boost: High-performance lithium-ion anode uses "bottom up, self-assembled" nanocomposite materials to increase capacity

Atlanta, GEORGIA — A new high-performance anode structure based on silicon-carbon nanocomposite materials could significantly improve the performance of lithium-ion batteries used in a wide range of applications from hybrid vehicles to portable electronics.

Produced with a “bottom-up” self-assembly technique, the new structure takes advantage of nanotechnology to fine-tune its materials properties, addressing the shortcomings of earlier silicon-based battery anodes.  The simple, low-cost fabrication technique was designed to be easily scaled up and compatible with existing battery manufacturing.

Details of the new self-assembly approach were published online in the journal Nature Materials on March 14.

“Development of a novel approach to producing hierarchical anode or cathode particles with controlled properties opens the door to many new directions for lithium-ion battery technology,” said Gleb Yushin, an assistant professor in the School of Materials Science and Engineering at the Georgia Institute of Technology.  “This is a significant step toward commercial production of silicon-based anode materials for lithium-ion batteries.”

The popular and lightweight batteries work by transferring lithium ions between two electrodes – a cathode and an anode – through a liquid electrolyte.  The more efficiently the lithium ions can enter the two electrodes during charge and discharge cycles, the larger the battery’s capacity will be.

Existing lithium-ion batteries rely on anodes made from graphite, a form of carbon.  Silicon-based anodes theoretically offer as much as a ten-fold capacity improvement over graphite, but silicon-based anodes have so far not been stable enough for practical use.

“At the nanoscale, we can tune materials properties with much better precision than we can at traditional size scales,” said Yushin.  “This is an example of where having nanoscale fabrication techniques leads to better materials.”

Electrical measurements of the new composite anodes in small coin cells showed they had a capacity more than five times greater than the theoretical capacity of graphite.

Once fabricated, the nanocomposite anodes would be used in batteries just like conventional graphite structures.  That would allow battery manufacturers to adopt the new anode material without making dramatic changes in production processes.

So far, the researchers have tested the new anode through more than a hundred charge-discharge cycles.  Yushin believes the material would remain stable for thousands of cycles because no degradation mechanisms have become apparent.

“If this technology can offer a lower cost on a capacity basis, or lighter weight compared to current techniques, this will help advance the market for lithium batteries,” he said.  “If we are able to produce less expensive batteries that last for a long time, this could also facilitate the adoption of many ‘green’ technologies, such as electric vehicles or solar cells.”

Adapted from Georgia Institute of Technology news.

Back to Nano News