Scientists will create lithium-ion battery for nano-scale devices

Scientists are trying to create some of the tiniest lithium-ion batteries on earth which will be no bigger than a grain of sand.

The research, funded by DARPA, aims to reduce the size of lithium-ion batteries, commonly used in electrical goods, so they can be used to power electronics and mechanical components of micro- to nano-scale devices.

Jane Chang, an engineer at the University of California, Los Angeles, is designing one component: the electrolyte that allows charge to flow between electrodes.

“We’re trying to achieve the same power densities, the same energy densities as traditional lithium ion batteries, but we need to make the footprint much smaller,” she said.

She is working with Bruce Dunn and other researchers at UCLA to coat micro-pillars or nano-wires, which have been designed to maximise the surface-to-volume ratio. This is the potential energy density coupled with electrolyte, the conductive material that allows current to flow in a battery.

Using atomic layer deposition, a slow but precise process which allows layers of material only an atom thick to be sprayed on a surface, Chung has successfully applied the solid electrolyte lithium aluminosilicate to nanomaterials.

Researchers say a solid electrolyte lithium aluminosilicate (LiAlSiO4) is a promising candidate due to high ionic conductivity along its c-axis – resulting from channels formed by the alternating tetrahedra of aluminum-oxygen (Al-O) and silicon-oxygen (Si-O). They said the length of c-axis of lithium aluminosilicate can be adjusted by changing the crystallisation temperature for desired conductivity characteristics.

The research, presented yesterday, is still in very early stages.