Can innovations in materials science help make our world a cleaner place? Argonne National Lab’s Vilas Pol was recently featured on the PBS NOVA series Making Stuff, where he shared his innovative approach of converting plastic bags into rechargeable battery components. Dr. Pol recently took some time out of his busy day to give us the inside scoop on how he stumbled upon this solution and next steps for the project.
Question: What led you to become a materials scientist?
Vilas Pol: With curiosity in chemistry, I earned my Master of Science and Master of Philosophy degrees in chemistry from the premier Pune University of India. In 2000, I was willing to do a Ph.D. in nanoscience. Soon after, I realized that the knowledge of only chemistry is not sufficient for it; rather, this new field bridges the expertise of chemists, physicists and engineers. With that in mind, I tried to learn many other things in materials science. My logic is to develop a variety of fascinating materials with innovative approaches beyond the traditional ones. Typically, I fabricate novel functional materials for their immediate applications, including energy conversion systems (dye sensitized solar cells) and energy storage devices (rechargeable lithium ion batteries). Recently, I’ve even tackled one of the foremost environmental problems that have negative impacts on human life and ultimately the environment. All of these probing facts led me to become a materials scientist.
Q: Did you have a teacher or role model growing up who inspired you to pursue a career in science?
VP: Certainly, I had an incredible mentor, Professor V. G. Dedgaonkar during my Master of Philosophy degree in India. He taught me the basic scientific principles and the methodical ways to look at scientific problems to solve them in a distinct way. In addition, brainy Emeritus Prof. Aharon Gedanken from Bar-Ilan University of Israel influenced me entirely with the materials science milieu during my Ph.D.
Q: Let’s talk about your incredible project that converts plastic bags into battery component - how did you stumble upon this solution?
VP: Plastic bags are a problem everywhere in the world. Not only the plastic bags, but also a variety of other waste plastic like plates, cups, milk containers and even some car parts. Once the plastic is made, it is getting used for a while and then thrown to the environment, where it takes hundreds of years to decompose. One way to get rid of this used plastic is to recycle it. Generally, when different types of plastics are melted together, they tend to phase separate, causing structural weakness in the resulting plastic material. Therefore in order to make something usable from waste plastics, the required polymers need to be sorted out from the mixed stuff. Thus the existing recycling process is not cost effective and makes it less appealing as a long term solution. So I thought why not to go beyond this traditional method and try to convert the waste polymers into more value added products such as carbon spheres and carbon nanotubes.
Since I am working closely with the well-known distinguished scientist Dr. Michael Thackeray in the battery division of Argonne, we tested those distinct spheres and nanotubes as an anode material for a rechargeable lithium ion battery. As a result, we have found that the synthesized completely spherical carbon particles have an advantage in battery safety, and so are good candidates for battery applications. The anode is one of the important components of batteries, and one day it could be made from trashed plastic.
Q: You mentioned that the carbon spheres and nanotubes have a variety of potential applications – can you tell us a bit about these possible uses?
VP: Usually carbon is produced by breaking down petroleum gas or coal. Instead of using the expensive hydrocarbons, I thought to get rid of existing waste plastic and convert it to carbonaceous products. These carbon spheres and carbon nanotubes have significant properties and can be used for different applications such as components of batteries, toners of printers, additives for lubrication, carbon black for high performance tires, etc.
A simple example of carbon spheres, which I make via plastic ‘upcycling’ has micrometer size and properties of carbon black, a key element of toners. Thus, our carbon spheres in addition to the polymeric additives can make toners for printers or photocopy machines, which we use every day.
We have also measured electrical conductivity of single carbon spheres. Due to their conducting nature, one can make carbon black pigments for paints and coatings. Moreover, the non-conducting polymers can become conducting after adding a small amount of carbon nanotubes during their fabrication.
Through collaboration with Argonne’s tribology expert Dr. Ali Erdmeir and his postdoc Dr. Kuldeep Mistry, we are also exploring our carbon products with oil as an effective additive to reduce friction.
I wanted to tackle the plastic waste problem in a way that the solution is worthwhile and I think it is.
Q: About how many plastic bags fit inside your reactor?
VP: I have a small prototype reactor of 80 cubic centimeter volume developed in our lab, which can easily digest three to four plastic bags and create several grams of material at a time. Now we are discussing with outside companies in order to scale up this upcycling process to produce mass quantities of functional carbon products from used plastics.
Q: Changing gears slightly, what can you never start a day at the lab without?
VP: I never start a day at the lab without doing some exercise. It is highly important to do exercise for a minimum of 30 minutes almost every day. If my body machine does not work well then the other projects associated with me won’t run effectively. Thus, I start my day keeping myself fit and energetic to work with maximum efficiency.
Q: Do you have a favorite tool?
VP: I do have my specially designed autogenic reactor to convert the waste plastic to carbonaceous products. Beyond this, I use it for making a variety of other fascinating anode and cathode materials for battery applications. I make laminates of resulting materials, which go into coin cells to test the electrochemical performance. We have many sophisticated tools including a cycler, which helps us understand if the developed material is useful. I test the synthesized materials in this reactor for rechargeable batteries almost every day.
Q: What do you enjoy doing in your free time?
VP: Do scientists have free time? Whatever time I get, I spend it in exploring others’ research development and with family. I spend time with my 6 year old daughter Hurshal, who has an enormous fascination about science and I continue having scientific discussions with my wife, Swati as she has a similar research background.
Q: Back to plastic bags — what are the next steps for this approach?
VP: Keeping in mind the huge negative impact of plastic waste on the environment, I have developed the upcycling approach at the laboratory level. Almost everyone is creating plastic waste and we need to get rid of it at a large extent. We are seeking additional help from industrial engineers to design a scalable reactor for this vital upcycling process. I think down the road, if we combine the efforts, maybe in a year or two we should be able to start upcycling a huge amount of plastic into important carbonaceous materials.
Q: Last question, what makes this project unique from the environmental standpoint?
VP: As of today, most plastic waste goes to a landfill or is drowned in the sea. Its decomposition takes years and years, increasing areas of infertile land with time and also badly affecting the marine world.
As I mentioned earlier, there is a traditional recycling approach where a community accumulates various plastics to send it to the recycling companies. These companies try to sort out the different polymers for successful recycling. The separation of mixed plastic is labor or energy intensive and not cost effective. Therefore, the existing techniques to take care of waste plastic are totally different as compared to our upcycling approach.
Here, we are not only getting rid of the omnipresent plastic waste but also substituting the petrochemical feedstock to produce carbon based materials for various interesting applications. Additionally, to produce carbon nanotubes the traditional approaches need a special reaction environment, catalysts, vacuum systems and high energy inputs. In the present scenario, since we are using the waste plastic as a raw material with minimum process requirements, it becomes a useful and still less expensive alternative. We also have the ability to tune the reaction parameters to synthesize different forms of resulting carbon products depending upon the requirement. I believe the described unique environmentally benign plastic upcycling process is an effectual two-in-one solution to the waste plastic problem and to the production of valuable carbonaceous materials.