We’ve already seen the news about how researchers at the Massachusetts Institute of Technology have recycled dead car batteries to create clean solar power. Now scientists at the Oak Ridge National Laboratory are cannibalizing old tires to help lithium-ion batteries power electric cars and store solar and wind energy.
Rubber tires contain a substance called pyrolytic carbon black, and by extracting it from discarded tires and modifying its microstructural characteristics, a team of researchers is building a better anode for batteries. (Anodes are negatively charged electrodes used for storing lithium while the battery is charging.)
Oak Ridge, a division of the U.S. Department of Energy, reports in the journal RSC Advances that it has developed a proprietary method of recovering pyrolytic carbon black, an artificial form of graphite.
When this substance was used for lithium-ion anodes, it produced a small prototype battery with a greater charge-discharge capacity than would have been possible when using conventional graphite.
One of the team’s leaders, Parans Paranthaman, said the approach has several advantages over conventional methods of making anodes for lithium-ion batteries. For starters, he says, not only do they recover valuable carbon materials that otherwise would go to waste, they also limit the environmental damage caused by throwing away old tires.
They’re also much less expensive than batteries using conventional graphite and are more durable, he said.
The Oak Ridge prototype’s capacity measured nearly 390 milliamp-hours per gram of artificial graphite after 100 charge-discharge cycles, better than the best commercial natural graphite. Paranthaman attributes this performance increase to the altered microstructure of the tires’ carbon.
“This kind of performance is highly encouraging, especially in light of the fact that the global battery market for vehicles and military applications is approaching $78 billion and the materials market is expected to hit $11 billion in 2018,” Paranthaman said.
Using Oak Ridge’s technique, these costs can be reduced significantly, according to the team’s co-leader, Amit Naskar, because anodes now cost between 11 and 15 percent of all the materials used in lithium-ion batteries. “This technology addresses the need to develop an inexpensive, environmentally benign carbon composite anode material with high-surface area, higher-rate capability and long-term stability,” Naskar said.
The Oak Ridge National Laboratory says it plans to work with private companies in the United States to license the new technology for use in cars, stationary energy storage, as well as both military and medical applications. Another possibility, it says, is for water filtration and storage of gases.
Meanwhile, other members of the Oak Ridge team are trying out a pilot manufacturing process that would increase the amount of pyrolytic carbon black recovered from discarded tires, so that even bigger batteries can be built.
By Andy Tully of Oilprice.com
Andy Tully is a veteran news reporter who is now the news editor for Oilprice.com