Turning Packing Peanuts Into Battery Electrodes

Chemical engineers have carbonized packing peanuts and used the resulting carbon microsheets to construct lithium battery anodes that rival the performance of conventional graphite ones. If commercialized, the method would help find a use for the packaging, which often ends up in landfills. Lithium-ion battery anodes are usually made from graphite, which absorbs and releases lithium ions during charging and discharging. To make the new anodes, Vilas G. Pol of Purdue University and colleagues first heated polystyrene or starch peanuts from 500 to 900 ºC for a couple of hours under an atmosphere of argon. They also added a metal-salt-based catalyst when carbonizing polystyrene particles. The researchers made anodes from the ground carbonized peanuts and tested their performance in coin-cell batteries. Compared with batteries with a conventional anode, the Purdue team’s batteries charged faster because the microsheets are thinner than graphite. Also, the storage capacity of the peanut anodes was about 13% greater than the theoretical capacity for graphite anodes. This is because the microsheets formed a more disordered, porous network compared with graphite, allowing for greater absorption of lithium ions.