United States – Researchers at Purdue University in the USA have found a patent-pending way to convert the foam ‘peanuts’ used as a packing medium into high-performance carbon electrodes for rechargeable lithium-ion batteries. These ‘outperform conventional graphite electrodes’, it is claimed.
‘Although packing peanuts are used worldwide as a perfect solution for shipping, they are notoriously difficult to break down, and only about 10% are recycled,’ says Professor Vilas Pol, who inspired the project. Manufacturing carbon-nanoparticle and microsheet anodes from polystyrene and starch-based packing peanuts will divert this material from landfill – ‘where it remains intact for decades’.
The new method offers ‘a very simple, straightforward approach’, Pol notes. ‘Typically, the peanuts are heated between 500 and 900 degC 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,’ adds post-doctoral research associate Vinodkumar Etacheri. Microscopic and spectroscopic analyses prove the microstructures and morphologies responsible for ‘superior electrochemical performances’ are preserved after many charge-discharge cycles.
Commercial anode particles are about 10 times thicker than the new anodes and have higher electrical resistance, thus increasing charging time. ‘Because the sheets are thin and porous, they allow better contact with the liquid electrolyte in batteries,’ the researchers point out.
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