From allergens to anodes: pollen derived battery electrodes
07 February 2016
Pollens, the bane of allergy sufferers, could represent a boon for battery makers as recent research suggests their potential use as anodes in lithium-ion batteries.
The anodes in most of today's lithium-ion batteries are made of graphite. "Our findings have demonstrated that renewable pollens could produce carbon architectures for anode applications in energy storage devices," says Vilas Pol, an associate professor at Purdue University. The researchers tested bee pollen and cattail pollen-derived carbons as anodes.
"Both are abundantly available," says Pol. "The bottom line here is we want to learn something from nature that could be useful in creating better batteries with renewable feedstock."
Whereas bee pollen is a mixture of different pollen types collected by honey bees, the cattail pollens all have the same shape.
The researchers processed the pollen under high temperatures in a chamber containing argon gas via a process of pyrolysis, yielding pure carbon in the original shape of the pollen particles. They were further processed, or 'activated', by heating at lower temperature - about 300 degrees Celsius - in the presence of oxygen, forming pores in the carbon structures to increase their energy-storage capacity.
The research showed the pollen anodes could be charged at various rates. While charging for ten hours resulted in a full charge, charging them for only one hour resulted in more than half of a full charge. "The theoretical capacity of graphite is 372 milliamp hours per gram, and we achieved 200 milliamp hours after one hour of charging," says Pol.
Pol and his co-researcher, doctoral student Jialiang Tang, tested the carbon at 25 degrees Celsius and 50 degrees Celsius to simulate a range of climates to which the batteries might be subject. Findings showed the cattail pollens performed better than bee pollen.
Whereas the current work studied the pollen only in anodes, future research will include work to study them in a full-cell battery with a commercial cathode.
This research is described in an article published in the journal, Scientific Reports.