Text Size
Facebook Twitter More...

University of Alberta chemists have taken a critical step toward creating a new generation of silicon-based lithium ion batteries with 10 times the charge capacity of current cells.

"We wanted to test how different sizes of silicon nanoparticles could affect fracturing inside these batteries," said Jillian Buriak, a U of A chemist and Canada Research Chair in Nanomaterials for Energy.

Silicon shows promise for
buildingmuch higher-capacity batteries because it's abundant and can absorb much more lithium than the graphite used in current lithium ion batteries. The problem is that silicon is prone to fracturing and breaking after numerous charge-and-discharge cycles, because it expands and contracts as it absorbs and releases lithium ions.

Existing research shows that shaping silicon into nano-scale particles, wires or tubes helps prevent it from breaking. What Buriak, fellow U of A chemist Jonathan Veinot and their team wanted to know was what size these structures needed to be to maximize the benefits of silicon while minimizing the drawbacks.

The researchers examined silicon nanoparticles of four different sizes, evenly dispersed within highly conductive graphene aerogels, made of carbon with nanoscopic pores, to compensate for silicon's low conductivity. They found that the smallest particles—just three billionths of
ametre in diameter—showed the best long-term stability after many charging and discharging cycles.

"As the particles get smaller, we found they are better able to manage the strain that occurs as the silicon 'breathes' upon alloying
anddealloying with lithium, upon cycling," explained Buriak.

The research has potential applications in "anything that relies upon energy storage using a battery," said Veinot, who is the director of
theATUMS graduate student training program that partially supported the research.

That would be world changing. To read more, click here.


Category: Science