Researchers in the US have come across what could be a new anode for lithium batteries – pollen.

“Our findings have demonstrated that renewable pollens could produce carbon architectures for anode applications in energy storage devices,” said Vilas Pol, an associate professor and engineering researcher at Purdue University.

Batteries have two electrodes - an anode and a cathode. The anodes in most of today's lithium-ion batteries are made of graphite. Lithium ions are contained in a liquid called an electrolyte, and these ions are stored in the anode during recharging.

The researchers tested bee pollen- and cattail pollen-derived carbons as anodes.

“Both are abundantly available,” said Pol.

“The bottom line here is we want to learn something from nature that could be useful in creating better batteries with renewable feedstock.”

The researchers processed the pollen under high temperatures in a chamber containing argon gas using a procedure called 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 10 hours resulted in a full charge, charging them for only one hour resulted in more than half of a full charge, Pol said.

“The theoretical capacity of graphite is 372 milliamp hours per gram, and we achieved 200 milliamp hours after one hour of charging.”

The researchers tested the carbon at 25 degrees Celsius and 50 degrees Celsius to simulate a range of climates.

Findings showed the cattail pollens performed better than bee pollen.

“We are just introducing the fascinating concept here,” Pol said.

“Further work is needed to determine how practical it might be.”

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