Glass bottles produce silicon anodes for advanced batteries

Engineers at the University of California, Riverside (UCR) have used waste glass bottles and a low-cost chemical process to create nanosilicon anodes for high-performance lithium-ion batteries. These batteries could extend the range of electric vehicles and plug-in hybrid electric vehicles, and provide more power with fewer charges for personal electronic devices like cell phones and laptops.

Cengiz Ozkan, professor of mechanical engineering, and Mihri Ozkan, professor of electrical engineering, led the project, which is described in a paper in Scientific Reports.

Even with today's recycling programs, billions of glass bottles end up in landfills every year, prompting the UCR researchers to ask whether silicon dioxide in waste beverage bottles could provide high purity silicon nanoparticles for lithium-ion batteries.

Silicon anodes can store up to 10 times more energy than conventional graphite anodes, but expansion and shrinkage during charge and discharge make them unstable; downsizing silicon to the nanoscale has been shown to reduce this problem. By combining an abundant and relatively pure form of silicon dioxide and a low-cost chemical reaction, the researchers have now created lithium-ion half-cell batteries that store almost four times more energy than conventional graphite anodes.

To create the silicon anodes, the team used a three-step process that involved first crushing and grinding the glass bottles into a fine white power. Next, a magnesiothermic reduction transforms the silicon dioxide into nanostructured silicon, which is then coated with carbon to improve its stability and energy storage properties.

As expected, coin cell batteries made using the glass bottle-based silicon anodes greatly outperformed traditional batteries in laboratory tests. Carbon-coated glass derived-silicon (gSi@C) electrodes demonstrated excellent electrochemical performance with a capacity of around 1420mAh/g at C/2 rate after 400 cycles.

Changling Li, a graduate student in materials science and engineering and lead author of the paper, said that one glass bottle provides enough nanosilicon for hundreds of coin cell batteries or three to five pouch cell batteries.

"We started with a waste product that was headed for the landfill and created batteries that stored more energy, charged faster and were more stable than commercial coin cell batteries. Hence, we have very promising candidates for next-generation lithium-ion batteries," Li said.

This research is the latest in a series of projects led by Mihri and Cengiz Ozkan to create lithium-ion battery anodes from environmentally-friendly materials. Previous research has focused on developing and testing anodes made from portabella mushrooms, sand and diatomaceous (fossil-rich) earth.

This story is adapted from material from the University of California, Riverside, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.