Purdue researchers convert packing peanuts into anode materials for Li-ion batteries; outperforming graphite
Purdue researchers have developed a process to manufacture carbon-nanoparticle and microsheet anodes for Li-ion batteries from polystyrene and starch-based packing peanuts, respectively. The work, performed by postdoc Vinodkumar Etacheri, Professor Vilas Pol and undergraduate chemical engineering student Chulgi Nathan Hong, is being presented at the 249th American Chemical Society National Meeting & Exposition in Denver.
Packing-peanut-derived carbon anodes have 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).
The researchers cycled the anodes 300 times without significant capacity loss. These carbonaceous electrodes could also be used 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.
We were getting a lot of packing peanuts while setting up our new lab. Professor Vilas Pol suggested a pathway to do something useful with these peanuts.—Vinodkumar Etacheri
Research findings indicate that the new anodes can charge faster and deliver higher specific capacity compared to commercially available graphite anodes, Pol said.
The new method heats the peanuts 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 process is inexpensive, environmentally benign and potentially practical for large-scale manufacturing. Microscopic and spectroscopic analyses proved the microstructures and morphologies responsible for superior electrochemical performances are preserved after many charge-discharge cycles.—Vinodkumar Etacheri
Commercial anode particles are about 10 times thicker than the new anodes and have higher electrical resistance, which increase charging time. Because the packing peanut-derived sheets are thin and porous, they allow better contact with the liquid electrolyte in batteries.
The researchers acknowledge funding from Purdue University, the university’s School of Chemical Engineering and the Kirk Endowment grant from the Birck Nanotechnology Center. Purdue’s Office of Technology Commercialization filed a US patent application on the technology in 2014.