TUESDAY 25 DECEMBER, 2012 |
Plants Could Help Make Lithium-Ion Batteries Greener
With the home
revolution about to begin; anything that can make lithium-ion
batteries a little more environmentally friendly is a welcome development.
Scientists at Rice University and the City College of New York say the madder
plant is a good source of purpurin, an organic dye that can be turned into an
effective, natural cathode for lithium-ion batteries.†
The madder family incorporates around 80 species of perennial plants. The
species in this case is Rubia tinctorum, the common madder, which has been used
since ancient times as for dyeing applications.
Lithium-ion batteries use cathodes made of lithium cobalt oxide, which is not
only very expensive; but the process of mining the cobalt metal and
manufacturing the cathodes is energy intensive and has other associated
environmental problems. Lithium-ion batteries have a long service life and can
be recycled, but extracting the cobalt is also an energy intensive process.
While testing a number of organic molecules for their ability to electrochemically interact with lithium,
Rice research scientist Arava Leela Mohana Reddy and his team found purpurin most
responsive to binding lithium ions and he says purpurin could be extracted from
agricultural waste. The cathodes can also be made at room temperature.
Reddy's ultimate goal is create completely green batteries and he expects to have a working prototype of a complete organic battery within a few years.†
The purpurin discovery is the subject of a paper that can be viewed on Scientific
"Green batteries are the need of the hour, yet this topic hasnít really been addressed
properly," says Reddy. "Itís a new mechanism we are proposing with
this paper, and the chemistry is really simple."
Aside from home energy storage and electric vehicle applications, a greener
lithium ion battery will have a substantial positive impact on the environmental
footprint of consumer electronics.
Demand for Li-ion is set to skyrocket in the years ahead - in China alone, the lithium-ion battery market
is forecast to nearly double
USD$9.2 billion in 2016, as volumes grow 129 percent to 44.3 GWh.
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