Boffins use nano-tech to boost lithium-ion batteries

Scientists are working to improve the performance of lithium-ion batteries used in mobile computing devices through a process dubbed nano-structuring, or the extreme reduction of size.

Researchers at Delft University of Technology predicted that the nano-structuring of battery materials is likely to be common practice in the future, but warned that the process is not always performance enhancing.

The research, recently published in the Journal of the American Chemical Society, noted that a lithium-ion battery is currently the smallest and lightest way to store as much rechargeable electrical energy as possible. But the batteries are slow to charge and discharge.

This sluggish performance is largely determined by the relatively long distance the lithium-ions have to travel through the electrode material in the battery.

The speed at which the ions make their way through the electrode material is also slow compared to that in electrolyte (the fluid between the electrode material).

The researchers pointed out that nano-structuring the electrode particles to make them very small (measurable in nanometres) will shorten the existing route within the electrode material.

However, the battery performance of materials nano-structured in this way has so far failed to meet expectations.

"To a great extent, these discrepancies were not understood. By using neutron-diffraction research technology, researchers at Delft's Reactor Institute Delft have discovered that the properties of the material structure change significantly when the electrode particles are scaled down," the researchers said.

"The phase balance generally present in this type of material changes and even disappears completely if the electrode sections become small enough."

Based on these findings, the researchers can predict how the nano-structures will affect the performance of the lithium-ion batteries.

They have concluded that the nanostructures of the electrode materials in lithium-ion batteries is largely dependent on the material and the exact particle size.