Sand is an environmentally friendly, non toxic and low-cost material that makes higher energy density electrodes for the sand based lithium ion batteries as compared to those made from graphite.
Sand contains quartz (silicon dioxide), which has superior electrical properties suitable for the production of efficient Lithium battery electrodes. The current batteries use graphite electrodes which have somehow been pushed to the limits. Sand based electrodes on the other hand have higher capacity and can improve the battery performance by about 300 percent.
A graduate student at the University of California, Zachary Favors, says that the sand provides a low-cost, environmentally friendly and non toxic solution for the lithium batteries.
Favors and two engineering professors Mihri Ozkan and Cengiz Ozkan, are the brains behind the development of the improved sand based lithium battery. The increased energy density of the battery is due to the porosity of the sponge-like Silicon material that is processed from the sand.
With this technology, most of the portable d.c powered equipment such as cars, Smartphones, laptops, and much more, will have batteries lasting three times longer than the standard graphite based.
Producing pure silicon from sand
Producing silicon at the nanoscale level (billionths of a meter), starts with milling down of the sand to the nanometer scale, several purification steps are then used, resulting into color and texture change from the natural brown sand to bright white, sugar like powder.
The next step involves adding grounded salt and magnesium into the above purified quartz, and then heating of the resulting powder. The salt absorbs the heat while the magnesium removes the oxygen from the silicon hence producing pure silicon.
( a) Flow chart showing conventional synthesis routes of nano-Si, including the introduction of our synthesis route from sand. Optical images of (b) unpurified sand, (c) purified sand, and (d) (from left to right) vials of unpurified sand, purified sand, and nano-Si. (e) Schematic of the heat scavenger-assisted Mg reduction process.
credit: nature.com
There is, however a challenge with the nanoscale silicon, which degrades quickly and hard to produce in large quantities. However, the technique is still in the early stages and not yet commercial due to the low production. This will surely change the electronics field once efficient and commercial production comes into place. And people will be able to enjoy their gadgets which continue to become more advanced and power-hungry.