Foam peanuts, also known as packing peanuts, styrofoam popcorn or packing noodles are a common loose-fill packaging and cushioning material used to prevent damage to fragile objects during shipping.Packing peanuts are used worldwide as a perfect solution for shipping, they are notoriously difficult to break down, and only about 10 percent are recycled. Due to their low density, huge containers are required for transportation and shipment to a recycler, which is expensive and does not provide much profit on investment.A team of chemical engineers at Purdue University have shown now how to convert waste packing peanuts into high-performance carbon electrodes for rechargeable lithium-ion batteries that outperform conventional graphite electrodes, representing an environmentally friendly approach to reuse the waste.The work was performed by Etacheri, Vilas Pol and undergraduate chemical engineering student Chulgi Nathan Hong..
Battery
Batteries have two electrodes, called 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. Now, researchers at Purdue University have shown how to manufacture carbon-nanoparticle and microsheet anodes from polystyrene and starch-based packing peanuts, respectively.
New method
The new method is a very simple. The peanuts are heated between 500 and 900 degrees Celsius in a furnace under inert atmosphere in the presence or absence of a transition metal salt catalyst.The resulting material is then processed into the anodes.The new anodes can charge faster and deliver higher “specific capacity” compared to commercially available graphite anodes.The process is inexpensive. Commercial anode particles are about 10 times thicker than the new anodes and have higher electrical resistance, which increase charging time.
.These electrodes exhibited notably higher lithium-ion storage performance compared to the commercially available graphite anodes.Packing-peanut-derived carbon anodes demonstrated a maximum specific capacity of 420 mAh/g (milliamp hours per gram), which is higher than the theoretical capacity of graphite (372 mAh/g), Etacheri said.
Long-term electrochemical performance of these carbon electrodes are very stable. We cycled it 300 times without significant capacity loss. These carbonaceous electrodes are also promising for rechargeable sodium-ion batteries. Future work will include steps to potentially improve performance by further activation to increase the surface area and pore size to improve the electrochemical performance.
The researchers acknowledge funding from Purdue, the university’s School of Chemical Engineering and a Kirk Endowment grant from the Birck Nanotechnology Center. Purdue’s Office of Technology Commercialization filed a U.S. patent application on the technology in 2014.
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