Waste-tire carbon to power EVs

Crain News Service report

OAK RIDGE, Tenn. (Sept. 5, 2014) — U.S. researchers have developed technology to convert scrap tires into material that can improve the performance of lithium-ion batteries used in electric vehicles (EVs) and wind- and solar-energy units.

By modifying the microstructural characteristics of carbon black recovered from waste tires, the team at the Oak Ridge National Laboratory (ORNL) said it believes it can provide a better anode for lithium-ion batteries.

The process is said to offer advantages over conventional approaches to making anodes—negatively charged electrodes used as a host for storing lithium during charging.

ORNL's technique uses a proprietary pre-treatment to recover pyrolytic carbon black material, which is similar to graphite but man-made.

When used in anodes of lithium-ion batteries, researchers produced a small, laboratory-scale battery with a reversible capacity that is higher than what is possible with commercial graphite materials. This is attributed to the unique microstructure of the tire-derived carbon.

After 100 cycles, the capacity measures nearly 390 milliamp hours per gram of carbon anode, according to ORNL. This, the U.S. researchers said, exceeds the best properties of commercial graphite.

“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,” said Parans Paranthaman of the project team.

Anodes are one of the leading battery components, with 11 to 15 percent of the materials market share, according to researcher Amit Naskar, who noted that the new method could eliminate a number of hurdles.

Mr. Naskar said the 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.”

ORNL said it plans to work with U.S. industry to license this technology and produce lithium-ion cells for automotive, stationary storage, medical and military applications.

The research on conversion of recycled tires to graphite powders was funded by the laboratory's Technology Innovation Program while the research on battery fabrication and electrochemical testing was sponsored by the U.S. Department of Energy's (DOE) Office of Basic Energy Sciences, Materials Sciences and Engineering Division.

UT-Battelle manages ORNL for the DOE's Office of Science, which it describes as “the single largest supporter of basic research in the physical sciences” in the U.S.

This report appeared on the website of European Rubber Journal, a UK-based sister publication of Tire Business. It includes information from the ORNL website.