Used PET Plastic Bottles Can Be Transformed into Electric Vehicle Batteries

A new study from Pennsylvania State University has successfully converted waste PET plastic bottle material into high-quality synthetic graphite that can be used in lithium-ion batteries for electric vehicles, smartphones, laptops, and renewable energy storage. Currently, the world produces around 300 million tonnes of plastic each year, half of which is single-use plastic, with PET plastic bottles as a major component. Meanwhile, demand for graphite is climbing rapidly and is expected to quadruple by 2030, with a single electric car requiring up to 70 kilogrammes of graphite for its anode alone. According to Earth, converting PET plastic into good graphite is actually very difficult. The polymer contains about 33 percent oxygen, which causes the material to harden into irregular char when heated. The traditional solution of adding metal catalysts such as iron, nickel, or cobalt is considered less than ideal because it leaves behind residue impurities that require additional chemical cleaning processes to meet battery purity standards. The Penn State research team converted PET plastic pieces without metal catalysts by mixing them with 2.5 percent graphene oxide through controlled heating. The graphene oxide acts as a template that directs the carbon atoms to stack neatly, producing graphite crystals with a width of 114 nanometres and a stack height of 27 nanometres, outperforming the metric size of natural graphite. Avoiding the use of metals is the most crucial part for the industry. Without a catalyst, there is no iron or nickel residue to be cleaned up later. This process is considered capable of cutting costs while reducing the environmental footprint of battery material production. For comparison, producing one tonne of battery graphite conventionally typically consumes around 11,000 megajoules of energy and releases about five tonnes of carbon dioxide. Remarkably, this method also produces two useful types of carbon simultaneously: graphitic carbon for lithium-ion anodes in electric cars, and hard carbon for cheaper sodium-ion batteries used in grid storage. Although many stages of work still lie ahead, the direction of the research, published in the journal Diamond and Related Materials, is already very clear. Materials usually treated as waste, such as PET plastic, are now beginning to be utilised as raw materials for advanced technology.