A new paper has just been published in Advanced Functional Materials, on the use of teeth of teeth belonging to the snail species Cryptochiton stelleri to improve solar cells and batteries. Science Daily reports on the new paper:
An assistant professor at the University of California, Riverside’s Bourns College of Engineering is using the teeth of a marine snail found off the coast of California to create less costly and more efficient nanoscale materials to improve solar cells and lithium-ion batteries.
The most recent findings by David Kisailus, an assistant professor of chemical and environmental engineering, details how the teeth of chiton grow. The paper was published Jan. 16 in the journalAdvanced Functional Materials. It was co-authored by several of his current and former students and scientists at Harvard University in Cambridge Mass., Chapman University in Orange, Calif. and Brookhaven National Laboratory in Upton, NY.
Kisailus, who uses nature as inspiration to design next generation engineering products and materials, started studying chitons five years ago because he was interested in abrasion and impact-resistant materials. He has previously determined that the chiton teeth contain the hardest biomineral known on Earth, magnetite, which is the key mineral that not only makes the tooth hard, but also magnetic.
In the just-published paper, “Phase transformations and structural developments in the radular teeth of Cryptochiton stelleri,” Kisailus set out to determine how the hard and magnetic outer region of the tooth forms.
His work revealed this occurs in three steps. Initially, hydrated iron oxide (ferrihydrite) crystals nucleate on a fiber-like chitinous (complex sugar) organic template. These nanocrystalline ferrihydrite particles convert to a magnetic iron oxide (magnetite) through a solid-state transformation. Finally, the magnetite particles grow along these organic fibers, yielding parallel rods within the mature teeth that make them so hard and tough.
“Incredibly, all of this occurs at room temperature and under environmentally benign conditions,” Kisailus said. “This makes it appealing to utilize similar strategies to make nanomaterials in a cost-effective manner.”
Kisailus is using the lessons learned from this biomineralization pathway as inspiration in his lab to guide the growth of minerals used in solar cells and lithium-ion batteries. By controlling the crystal size, shape and orientation of engineering nanomaterials, he believes he can build materials that will allow the solar cells and lithium-ion batteries to operate more efficiently. In other words, the solar cells will be able to capture a greater percentage of sunlight and convert it to electricity more efficiently and the lithium-ion batteries could need significantly less time to recharge.
Using the chiton teeth model has another advantage: engineering nanocrystals can be grown at significantly lower temperatures, which means significantly lower production costs.