Silicon, the basis of the chip industry for decades, may to come to the rescue of the battery industry.
Researchers at Georgia Tech have devised an anode (an electrode in a battery that plays a key role in charging and discharging electrons) that sports embedded silicon nanoparticles. Electrical measurements in some experimental coin batteries show that these carbon-silicon anodes have five times the capacity of a battery with a normal anode.
Anodes currently are made from graphite, the planar form of carbon. Silicon anodes, in theory, can greatly increase the capacity of batteries, but to date silicon-based anodes have been too unstable for mass production.
Georgia Tech gets around this by using something of a hybrid approach to the underlying material. It embeds silicon particles measuring less than 30 billionths of a meter wide into graphite tendrils. These particle strands then self-assemble into spheres measuring 30 millionths of a meter wide, which can then be coated onto a surface to make an anode. Thirty microns wide might sound small, but in material science, that's huge -- making the particles actually somewhat amenable to mass production.
The presence of the silicon, combined with the porous nature of the particles, allows for rapid flow of electrolyte, faster charging and greater electrical capacity.
"If this technology can offer a lower cost on a capacity basis, or a lighter weight compared to current techniques, this will help advance the market for lithium batteries," said Gleb Yushin, a Georgia Tech assistant professor and the lead author on a paper describing the material in Nature Materials. "If we are able to produce less expensive batteries that last for a long time, this could also facilitate the adoption of many 'green' technologies, such as electric vehicles or solar cells."
Will it make it to market? Who knows. Researchers are combing through various ideas -- zinc, lithium air, new cathodes -- to beef up batteries. While many are promising, commercializing the technology has been tough. Both Imara and Firefly Energy, two battery start-ups, went out of business recently.
