Recycling Waste Car Parts into Graphene

AZoM spoke with Professor James Tour and Ph.D. candidate Kevin Wyss from Rice University about their research that has looked at upcycling disused car parts into high-quality turbostratic graphene.

Please can you introduce yourself, your background, and how you began researching graphene materials?

James Tour (JT): Professor of Chemistry, Rice University

Kevin Wyss (KW): Hi, my name is Kevin Wyss, and I am an NSF Graduate Research Fellow and Ph.D. candidate at Rice University. I began my research in materials chemistry when I came to Rice in 2019. Previously, during my undergraduate at Auburn University, I worked on organic, coordination, and supramolecular chemistry. When I came to Rice University, Prof Tour’s lab had just started working on flash Joule heating and flash graphene – I knew I couldn’t pass up an opportunity to work in such a new and exciting field, and I have learned so much.

How much waste is produced from old or disused vehicles, and why is this such a problem?

KW: As cars strive to be more fuel-efficient, the amount of plastic per vehicle has increased to an average of 350 kg. When the car gets old and is eventually shredded, the metal is removed, and the plastic is typically burned or landfilled causing environmental problems. This means millions of kgs of plastic each year because cheap and efficient recycling methods aren’t common yet. The European Union implemented the end-of-life vehicle Directive to ensure that 95{09e594db938380acbda72fd0ffbcd1ef1c99380160786adb3aba3c50c4545157} of the raw materials in end-of-life vehicles are recovered by 2015. But, due to the cost of plastic recycling, almost all nations still fail to meet these guidelines today.

Your research has created a process that enables the upcycling of plastic parts from disused cars into graphene. Could you please describe the method through which this is possible?

JT: For our process, we started with end-of-vehicle waste plastic that came from a commercial automotive plastic stripper. It was dirty, with all kinds of polymers mixed together. We ground it into small pieces and then upcycled it using flash Joule heating, where we pass a current through the plastic, with a little bit of coal added to be conductive. This current heats the sample, first carbonizing the plastic, then converting it to high-quality turbostratic graphene, all in the span of less than 30 seconds.

All the contaminants in the waste plastic sublime out during this rapid heating process, and we are left with graphene powder that can be used without any further purification! So, we sent 20 grams of our graphene to Ford Motor Company, for their testing in new, next-generation graphene nanocomposites they use in cars. Ford put our graphene into new composites and it did all that was expected—toughening and sound-deadening. Then they sent us those graphene-foam composites, and we again flashed them all into new graphene. You see the prospects of endless upcycling?

What is the difference between recycling and upcycling?

KW: Recycling of plastics is well known – physically or chemically converting waste polymer into a plastic product that can be used again in the same or similar application. However, recycling processes often cost more or are more time and resource-intensive than making virgin polymer products.

By comparison, upcycling converts the waste polymer into a more valuable product, in this case graphene. Currently, graphene can cost more than $60,000 per ton, a much higher value than the ~$2,000 per ton value of HDPE polymer, for example. Because of the high-value product, upcycling is often viewed as a way to make the responsible disposal of polymer waste economically viable and incentivized. Plus, some types of plastics, like foam seat cushions, cannot be recycled. They are predominantly landfilled but could be upcycled using our process.

Image Credit: Simon Annable/Shutterstock.com

What applications can the new graphene from this process be used in?

JT: Graphene is starting to finally see large-scale industrial applications. Since February 2020, all Ford cars contain graphene in at least the foam cushion seats and under-hood insulation – so graphene could be in your driveway. Our upcycled graphene product has given similar or superior properties compared to commercial graphene when we test it in strengthening applications. 

KW: The graphene we have produced using flash Joule heating has been used in a number of material composites – from cement to polyurethane foams and other polymers, and even polyvinyl alcohol films. Graphene can significantly improve the mechanical, noise absorption, and moisture stability of composites.

Other applications of our graphene products have been electrochemical energy storage in rechargeable batteries or supercapacitors, and electrocatalysis. Coatings, filters, or inks may be some other applications of our graphene product.

How do the properties of the newly produced materials compare to those made through conventional means?

JT: Most graphene for bulk applications is made by the exfoliation, mechanically, by ultrasound or electrochemically, of graphite. Ours is a bottom-up synthesis where we make graphene through the assembly of the carbon-carbon bonds. 

KW: When compared to commercially available graphene, we found our upcycled graphene product to be more than twice as dispersible. Dispersing graphene in solvent is often the first step to using it in applications such as composites, so it is an essential property. Though it depends on the manufacturing method, we often find our graphene product is also purer and higher quality than most commercial graphenes.

Ford Motor Company, the car manufacturer, partnered with you on this research. What was their role and how does it feel to have immediate commercial interest? 

KW: Ford helped us significantly through every phase of the research process. They supplied us with the authentic end-of-life vehicle waste plastic from landfilled F-150 trucks, made and tested the automotive polymer foams enhanced with graphene, and their sustainability experts helped us conduct the life-cycle assessment. As a graduate student, it was fulfilling to see the interest of Ford and gain an understanding and appreciation for the material chemistry happening in industry.

How scalable is this method? When and how can we apply this to the majority of end-of-life vehicles?

JT: The scale of automotive waste plastic, millions of kgs, means that of course further scale-up of the process from a lab-scale reactor is required. However, Universal Matter is working to scale up the flash Joule heating process to be able to process tons of materials per day! 1 ton per day by the end of 2022, and 100 tons per day 1 year later. 

KW: Throughout this project, we wanted to make the process as practical and simple as possible. We did this by designing and constructing an all-in-one flash Joule heating system on a larger scale, using authentic end-of-life vehicle waste plastic, and making sure our process doesn’t require any sorting, washing, or expensive additives or purification.

We then tested the practical usefulness of our product by having Ford Motor Company, one of the industry leaders in graphene use, test our product in their automotive parts. The life-cycle assessment was carried out to confirm the efficiency and practicality of our process.

Are there any limitations in regard to the process you are yet to overcome?

KW/JT: We’ve been able to upcycle all types of waste plastic, even mixed streams or dirty streams. One consideration is that the yield of the flash Joule heating reaction can be improved upon to get more graphene out of every gram of plastic upcycled. We’re currently researching ways to improve the yield and get other value streams out of waste plastic through flash Joule heating.

How will this research contribute toward efforts to make the automotive industry more sustainable or circular?

JT: We have continued to work with Ford Motor Company studying other products that we can make using flash Joule heating, and the life-cycle analysis demonstrates that our method uses 88{09e594db938380acbda72fd0ffbcd1ef1c99380160786adb3aba3c50c4545157} less energy, 95{09e594db938380acbda72fd0ffbcd1ef1c99380160786adb3aba3c50c4545157} less water, and emits 80{09e594db938380acbda72fd0ffbcd1ef1c99380160786adb3aba3c50c4545157} less CO2 emissions than other graphene production methods. As the price of graphene now declines through this commercial plastic, graphene will enter more vehicle plastics that are slated to displace now metal parts. This is all about light-weighting the vehicle for greater energy efficiency.

KW: By showing that we can continuously upcycle polymers and even nanocomposite polymers into high-value graphene, we are demonstrating one way that the automotive industry can use the resources that are currently landfilled in a more sustainable and circular manner. And, due to the high value of graphene, it economically incentivizes the responsible waste management of end-of-life vehicle waste plastic.

What is personally the most exciting aspect of this new research for you?

JT: This can make an enormous impact upon the world in waste management. 

KW: Working closely with Ford Motor Company, and seeing the industrial interest in our lab’s research was really exciting for me, but learning to conduct cradle-to-gate life-cycle assessments was the most fulfilling. Life-cycle assessment is such a powerful tool to guide manufacturing in efficient and sustainable ways, and I was very grateful to work with and learn from experts from Ford and the rest of the field on this topic. The whole team at Ford is on the cutting edge of upcycling, recycling, and sustainable manufacturing, so I was happy to meet and work with such great collaborators.

Where can readers find more information?

Universal Matter Inc Website:

https://www.universalmatter.com/

A Rice University press release on this work:

https://news.rice.edu/news/2022/cars-could-get-flashy-upgrade

A video by Rice University describing the flash Joule heating process: https://news.rice.edu/news/2020/rice-lab-turns-trash-valuable-graphene-flash

Our first paper on flash Joule heating for graphene:

https://doi.org/10.1038/s41586-020-1938-0

A recent review paper on the industrial outlook of graphene and flash Joule heating:

https://doi.org/10.1002/adma.202106970

About:

Kevin Wyss

Kevin Wyss is a Ph.D. candidate at Rice University, researching graphene, upcycling of waste products, polymer engineering, sustainable production of nanomaterials, and is focused on applications in energy storage, electrocatalysis, and mechanical composites. He has been awarded the NSF Graduate Research Fellowship and Stauffer-Rothrock Fellowship. He received his B.S. degree in chemistry from Auburn University in Auburn, Alabama under the guidance of Prof. Anne Gorden and the mentorship of Prof. Richard Kemp.

Professor James Tour

See www.jmtour.com.