Battery life extended by carbon nanotube scaffolding

The research, published online in Advanced Materials, reportedly shows the potential of manufactured sheets of aligned carbon nanotubes coated with silicon, a material with a much higher energy storage capacity than the graphite composites typically used in lithium ion batteries.

‘Putting silicon into batteries can produce a huge increase in capacity—10 times greater,’ said Dr. Philip Bradford, assistant professor of textile engineering, chemistry and science at NC State. ‘But adding silicon can also create 10 times the problems.’

One significant challenge in using silicon is that it swells as lithium ion batteries discharge. As the batteries cycle, silicon can break off from the electrode - a process called pulverization - making batteries less stable.

When the silicon-coated carbon nanotubes were aligned in one direction the structure allowed for controlled expansion so that the silicon is less prone to pulverisation, said Xiangwu Zhang, associate professor of textile engineering, chemistry and science at NC State.