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, and by combining an abundant and relatively pure form of silicon dioxide and a low-cost chemical reaction, the researchers created lithium-ion half-cell batteries that store almost four times more energy than conventional graphite anodes.

Cengiz Ozkan, professor of mechanical engineering, and Mihri Ozkan, professor of electrical engineering, led the project.

To create the anodes, the team used a three-step process that involved:

1. Crushing and grinding the glass bottles into a fine white power;

2. A magnesiothermic reduction to transform the silicon dioxide into nanostructured silicon; and

3. Coating the silicon nanoparticles with carbon to improve their stability and energy storage properties.

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

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 from portabella mushrooms, sand, and diatomaceous (fossil-rich) earth.

In addition to Mihri and Cengiz Ozkan and Li, contributors include graduate students Chueh Liu, Wei Wang, Zafer Mutlu, Jeffrey Bell, Kazi Ahmed and Rachel Ye. Financial support for this work was provided by the UC-Riverside and UC Faculty Climate Champion initiative.

The UCR Office of Technology Commercialization has filed a patent application for the inventions above.

Resources

• Changling Li, Chueh Liu, Wei Wang, Zafer Mutlu, Jeffrey Bell, Kazi Ahmed, Rachel Ye, Mihrimah Ozkan & Cengiz S. Ozkan (2017) “Silicon Derived from Glass Bottles as Anode Materials for Lithium Ion Full Cell Batteries” Scientific Reports 7, Article number: 917 doi: 10.1038/s41598-017-01086-8