The carbon architecture basis of lithium-ion battery anodes can be created from pollen grains, according to new research from Purdue University.
The new work involved converting bee pollen and cattail pollen grains into carbon microstructures through “a facile, one-step, solid-state pyrolysis process in an inert atmosphere.” Findings were published in Nature’s journal Scientific Reports.
The lithium-ion battery anodes — carbonaceous particles air-activated at 300° Celsius to create pores, and increase energy storage — were tested at both room temperature (~25° C) and a higher temperature (~50° C).
Out of the two types of pollen used for carbonaceous particles — cattail and bee pollen — the cattail pollen performed better.
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At a C/10 rate, the ACP (activated cattail pollen) electrode delivered high specific lithium storage reversible capacities (590 mAh/g at 50 °C and 382 mAh/g at 25 °C) and also exhibited excellent high rate capabilities.
Currently, Lithium-ion batteries generally use graphite as the anode material, with a theoretical capacity of 372 mAh/g and excellent capacity retention over extended cycling. However, the Purdue team noted, with its low operating voltage (
One candidate is hard carbon which typically allows faster lithiation due to larger interlayer spacing, and higher cycling capacity than graphite due to the additional nanopore filling Lithium storage mechanism. Hard carbon materials of various morphologies are commonly prepared by direct pyrolysis or hydrothermal decomposition of biomass. Biomass sources can be carefully selected to fine tune the morphologies.
…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 — 200 milliamp hours per gram.
The researchers involved are now planning to test the pollen anodes in actual full-cell batteries with commercial cathodes.
The research paper itself can be found here.