The polystyrene used in packaging has proved a headache when it comes to disposal. There are few recycling options, which means the material usually ends up in landfill.
However, a team from Purdue University in the US has developed a way to convert polystyrene from waste packing into carbon electrodes for rechargeable lithium-ion batteries and the electrodes are said to outperform conventional graphite electrodes.
The method is simple and straightforward, according to Professor Vilas Pol. "Typically, the 'peanuts' are heated between 500 and 900°C in a furnace under inert atmosphere in the presence or absence of a transition metal salt catalyst."
According to the team, commercial anode particles are about 10 times thicker than the new anodes and have a higher electrical resistance, which increases charging time. "In our case, if we are lithiating this material during the charging of a battery it has to travel only 1µm, so you can charge and discharge a battery faster than your commercially available material," Prof Pol said.
Carbon anodes derived from polystyrene packaging demonstrated a maximum specific capacity of 420mAhr/g – higher than graphite's theoretical capacity of 372 mAh/g.
"Long term electrochemical performance of these carbon electrodes is very stable," said postdoctoral research associate Vinodkumar Etacheri. "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."
Author
Graham Pitcher
Source: www.newelectronics.co.uk