Charging electric car batteries with old tyres

This could be the ultimate recycling concept for the auto industry in which recycled car tyres give new life to lithium-ion batteries that in turn provide energy for electric vehicles. 

Researchers from the Department of Energy at the Oak Ridge National Laboratory in Tennessee (US) are researching the possibility of recycling tyres into batteries by changing the microstructural properties of carbon black, or soot, which can be retrieved from old tyres so that better anodes can be developed for lithium-ion batteries. During the discharge cycle, the positive lithium ions on the negative electrode migrate to the positive electrode (containing lithium).  The reverse happens during the charge cycle. 

The technique developed by ORNL uses a patented pre-treatment process for extracting carbon black by way of pyrolyse. The material is similar to graphite, but man-made. In order to use it in lithium-ion batteries, the researchers produced a small, laboratory-sized battery with a reversible capacity that was higher than possible with commercial grade graphite materials. After 100 cycles the capacity was measured at almost 390 mAh per gram on the carbon anode, which exceeded the best properties of commercial grade graphite. The researchers attribute the results to the unique microstructure of the carbon extracted from the old tyres. 

Cheap and environmentally-friendly

Anodes form one of the most important battery components, accounting for between 11 and 15 per cent of the natural resources market. The new technology provides answers to the demand for developing cheap and environmentally-friendly anode materials based on carbon composites, with large surface areas, rapid rates of charge and long-term stability.

The research centre is planning to collaborate with US industry so that together they can patent and produce lithium-ion cells for automotive, stationary power, medical and military applications. Other possible applications include water filtration, gas absorption and gas storage.

Work is also being carried out on a pilot study about upscaling the extraction rates from materials and demonstrating applications, such as anodes for lithium-ion batteries in large 'pouch cell' designs. Researchers anticipate that these batteries will be cheaper than the ones produced with commercial carbon powders.