OUTER PLANET 54 PETplanet Insider Vol. 24 No. 07+08/23 www.petpla.net OUTER PLANET Transformation of PET bottles into polymers for lithium-ion batteries A team of A*STAR (Agency for Science, Technology and Research, Singapore) scientists has successfully upcycled waste PET plastic into polymer electrolytes, which are key components for safer lithium-ion batteries (LiBs). The study is the first known report of a working lithium-ion battery assembled using polymers upcycled from PET plastics, which are used to make plastic bottles. The study was published in Journal of Materials Chemistry A in November 2022. “Upcycling waste plastics is a new strategy to give these ubiquitous yet commonly discarded materials a new lease of life to transform them into value-added new products for novel applications,” said Dr Derrick Fam, Deputy Head of the Polymer Composites department at A*STAR’s Institute of Materials Research and Engineering (IMRE), who led this study together with Dr Jason Lim, Deputy Head of the Soft Materials department at IMRE (Institute of Materials Research and Engineering). The researcher describes as particularly advantageous the fact that there is a well-developed waste collection infrastructure for PET plastics and that the waste streams are relatively uncomplicated, thus offering great potential for upcycling. “There is a rise in demand for sustainably-sourced materials for lithiumion batteries due to greater electrification. However, the use of waste PET plastics as a resource for polymer electrolytes has never been achieved till now. This represents our first attempt to upcycle waste PET plastics for this application”, said Dr Lim. Capitalising on existing properties Amongst the different types of plastic, PET is one of the most abundant plastics produced today, amounting to 31 million tonnes in 2019, according to data from Statista. PET plastics possess existing features that make them suitable to be upcycled into polymer electrolytes (PEs). They are made up of rigid terephthalate components, which contribute to their excellent mechanical properties and can be tapped on to enhance PEs’ mechanical robustness, which in turn facilitates device integration and fabrication. In addition, they possess easily breakable chemical bonds which allow these polymers to be repurposed into new chemical building blocks with ease. These can then be reconstituted into new polymers for fresh applications. Battery design Waste PET bottles were used by the team to design polyurethanebased PEs. Compared to conventional liquid electrolytes currently used in LiBs, PEs are promising alternative components in batteries that have the potential to eliminate safety hazards such as the risks of electrolyte leakage, uncontrolled heating, volume expansion, dendrite growth and fire hazards. After assessing the viability of the PET-derived polymers as solid polymer electrolytes, the team further evaluated their ionic conductivity and cycling performance when used as gel polymer electrolytes for LiBs. Findings from the study showed the potential of the polyurethanes derived from waste PET as polymer electrolytes for LiBs. They achieved a room temperature conductivity of 10-4S/cm as a gel-polymer electrolyte (GPE), which is comparable to existing commercial systems containing liquid electrolytes. The team also successfully assembled a working LiB using these polymers, and showed that cells can be repeatedly charged and discharged up to 150 cycles. Their promising performance paves the way for a future powered by more sustainable energy, where PET plastic waste can be transformed into PE materials for batteries, creating a circular economy. The team will also look to advance the technology for upcycling of waste plastics on a larger scale to create components for ecofriendly batteries. About the A*STAR The Agency for Science, Technology and Research (A*STAR) is Singapore’s lead public sector R&D agency. Through open innovation, they collaborate with partners in both public and private sectors to benefit the economy and society. As a Science and Technology Organisation, A*STAR intends to bridge the gap between academia and industry. www.a-star.edu.sg (Top, from left): Dr Jason Lim, Dr Derrick Fam, Dr Warintorn Thitsartarn, Dr Ding Ning, Ms Chien Sheau Wei; (Bottom, from left): Ms Loh Wei Wei, Dr Shermin Goh, Ms Tan Ming Yan and Dr Dorsa Safanama (source: A*STAR)
RkJQdWJsaXNoZXIy NTY0MjI=