Illustration of the geometries observed in the nano-silicon power from diatomaceous earth. (Image courtesy of UC Riverside.)
New research based on fossils could help further the development of more efficient battery electric vehicles (BEVs) and portable electronics. Electric vehicles currently have drawbacks such as limitations in range of travel due to battery capacities, and expensive battery replacement costs.
However, a team of engineers at the University of California, Riverside’s Bourns College of Engineering have come up with an energy-efficient and inexpensive method of creating silicon-based anodes for lithium-ion batteries, with the silicon being extracted from the fossils of single-celled algae called diatoms. This could lead to solutions for some of the limitations of battery electric vehicles.
Electric vehicles use a variety of battery types, with Lithium-ion based batteries being one of the most widespread and popular. All batteries consist of an anode, a cathode and an electrolyte, and in most typical Li-ion batteries, graphite is used to act as the material anode. However, graphite’s performance acts as a bottleneck in making more efficient batteries.
Silicon has been proposed as an alternative anode material, as it can store about 10 times more energy. But the production of silicon though the traditional method of carbothermic reduction is expensive, which has limited its use as an anode material.
The UCR team suggests that diatomaceous earth (DE) can be a cheap source of silicon. DE is a silicon-rich sedimentary rock, composed of the fossilized remains of diatoms. The UCR team was able to use this as a source of Silicon Dioxide (SiO2) and through a process called magnesiothermic reduction, they obtained pure silicon nano-particles.
The research was led by Mihri Ozkan, professor of electrical engineering, Cengiz Ozkan, professor of mechanical engineering and Brennan Campbell, graduate student in materials science and engineering. The team highlighted the fact that the preservation of the diatom cell walls (structures called frustules) led to a highly porous anode that allowed easy flow of the electrolyte.
This research has the potential of leading to more widespread use of silicon-based anodes and consequently the development of ultra-high capacity Li-ion batteries for BEVs and other portable electronics. These developments in turn, can lead to more economically viable BEVs, higher sales and a greater presence of electric vehicles on the roads in the future.
For more information on this research visit the report by the researchers at UCR here, and for more information on Lithium-ion batteries and their production, view a video here.