Hundreds of millions of tires reach the end of their first life each year in the United States. The majority of these tires are recycled into road paving materials, plastic additives, and other useful materials. But, a significant waste stream remains, providing an opportunity for new applications for wasted rubber.
This month, the chemistry journal RSC Advances published a paper outlining a process for converting used rubber tires into anodes for lithium-ion batteries. Authored by researchers at Oak Ridge National Laboratory (ORNL), this paper discusses the process for converting waste tire rubber into nanoporous carbon cakes. According to the authors, these cakes have been used successfully in small laboratory-scale batteries for a hundred charge-discharge cycles.
This method for producing the anode material from used rubber could provide another method for recycling the hundreds of millions of used tires that are produced across the United States each year. However, it will have to prove its competitiveness against other materials in order to achieve commercial success.
Today, the graphite is the anode material-of-choice for lithium ion batteries. However, according to their initial testing results, the ORNL battery has a higher reversible capacity than commercial graphite materials. According to a press release, these properties are due to the unique microstructure of the ORNL tire-derived carbon. In the words of lead researcher, Parans Paranthaman:
“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.”
Furthermore, the carbon material produced in this process could be used in water filtration, gas sorption and storage applications.
Moving forward, ORNL is looking to commercially license this technology (see #ORNL-TT-2014-08), moving it from bench to store shelves for "automobile, stationary storage, medical and military applications."
Photo Credit: Graphic courtesy of Oak Ridge National Laboratory