RESEARCHERS at the University of California have found a way to produce low-cost, non-toxic, high-performance lithium ion battery anodes.
Anodes for lithium ion batteries are currently made of graphite, but researchers looking for improved performance are investigating the use of silicon at the nanoscale level as a replacement for graphite. However, nanoscale silicon degrates quickly and is hard to produce in large quantities.
The researchers at the Bourns College of Engineering started by sourcing sand with a high percentage of quartz. They then milled the sand down to the nanometre scale, then purified it.
After grinding salt and magnesium into the purified quartz, the mixture was heated. With salt acting as a heat absorber, the magnesium worked to remove the oxygen from the quartz, resulting in pure silicon.
The pure nano-silicon was formed in a very porous 3D structure, like a sponge. This porosity was found to improve the performance of batteries built with the nano-silicon.
The improved performance could mean increasing the expected lifespan of silicon based electric vehicle batteries up to three times or more.
The energy density is more than three times higher than that of traditional graphite based anodes, which means cell phones and tablets could last three times longer between charges.