Thanks to chemists at the University of Alberta (U of A), we’re one step closer to silicon-based, lithium-ion batteries with a charge capacity 10 times greater than existing cells.
“We wanted to test how different sizes of silicon nanoparticles could affect fracturing inside these batteries,” says Jillian Buriak, U of A chemist and Canada research chair in Nanomaterials for Energy.
According to the U of A, an encouraging candidate for producing batteries with higher capacities is silicon. This is due to its superior absorption of lithium compared to graphite, which is currently in use.
What are the downsides? After running through a series of charge-and-discharge cycles, silicon is prone to fractures and breaks—when silicon absorbs and releases lithium ions, it also expands and contracts.
The team studied 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,” according to the university. After pushing through a number of cycles, it was the smallest particles that boasted the most promising long-term stability results. And when I say small, I’m talking only three billionths of a meter in diameter.
“As the particles get smaller, we found they are better able to manage the strain that occurs as the silicon ‘breathes’ upon alloying and de-alloying with lithium, upon cycling,” says Buriak.
U of A Chemist Jonathan Veinot brings to light the vast array of potential applications, ranging from “anything that relies upon energy storage using a battery.”
“Imagine a car having the same size battery as a Tesla that could travel 10 times farther or you charge 10 times less frequently, or the battery is 10 times lighter,” continues Veinot.
Next, the team will gear the silicon nanoparticles’ production toward faster and cost-effective methods.
To learn more, read the article, “Size and Surface Effects of Silicon Nanocrystals in Graphene Aerogel Composite Anodes for Lithium Ion Batteries,” published in Chemistry of Materials.
