Double wall silicon nanotubes (DWSiNT) are a type of nanostructure with the potential to increase the storage capacity and reduce the size of lithium ion batteries. The idea is to replace one of the internal anodes in the battery with these silicon coated in DWSiNTs to increase anode capacity by as much as one order of magnitude. Silicon atoms bond with up to four ions per atom whereas only one ion bonds with every six carbon atoms in traditional graphite anodes.
Research has shown single wall nanotube electrodes effective, but they suffer from “decrepitation”—the breakdown of the nanostructure leading to shortened effective usefulness of batteries tested with single wall silicon nanotubes. In single wall silicon nanotubes, the constant expansion and contraction of tubes during charge and discharge expose the silicon to electrolytes that bond with the Lithium, rendering that portion of the tube ineffective for further ion bonding.
DWSiNTs solve this issue by adding a solid silicon oxide outer wall to the silicon nanotube, allowing the nanotube to undergo expansion and contraction while protecting the nanotube from the electrolytic solution. The result is a lithium ion battery with extended useful life and increased energy storage without increasing battery size. This technology has the potential for success in home energy storage, electric vehicle and consumer electronic applications.
- Stable cycling of double-walled silicon nanotube battery anodes through solid–electrolyte interphase control. Nature Nanotechnology. 2012 ;7(5):310 - 315.
This advancement in lithium ion battery technology has the potential to enhance the energy efficiency and decrease losses in transfer and recovery of energy from lithium ion batteries. This technological advancement can potentially reduce the cost and size of lithium ion battery systems in applications including renewable energy storage systems, consumer electronic applications, and transportation applications.
DWSiNTs have the potential for release into and reaction with human surroundings through workplace and disposal mechanisms. DWSiNTs are classified as UFPs by pulmonary toxicologists and studies have shown UFPs to have higher toxicity than micron sized particulates in similar dose to body weight ratios.