A technology has been developed to process mask waste into advanced materials that can enhance battery performance. This recycling of waste plastic is expected to protect the environment and lead to the development of a core technology for use in advanced industries.

A research team led by Professor Ahn Kwang-jin of the Department of Energy and Chemical Engineering at UNIST (President Yong-Hoon Lee) announced on the 18th that they have developed a process for producing carbon nanotubes from mask waste and applying them as positive electrode conductive materials for lithium-ion batteries.

“Producing carbon nanotubes from mask waste and studying their battery performance is a good example of plastic upcycling development,” said first author Nam Eon-woo, a researcher. “The process is not limited to mask waste, but can also be applied to other waste plastics with similar structures.”

Pyrolysis is one of the representative chemical recycling methods, and is a technology that produces pyrolysis oil and hydrocarbon gas from waste plastic. The hydrocarbon gases produced during this process, such as methane, ethylene, and propylene, are used as raw materials for the synthesis of carbon nanotubes (CNTs), a high-value-added carbon material. Carbon nanotubes are used in a variety of industrial fields due to their excellent thermal and electrical conductivity and mechanical strength.

Professor Ahn Gwang-jin of the Department of Energy and Chemical Engineering stated, “If we sequentially utilize two technologies – ‘thermolysis’ and ‘chemical vapor deposition’, which decomposes hydrocarbons at high temperatures – we can upcycle waste plastics to produce carbon nanotubes, a cutting-edge material.”

Carbon nanotubes are attracting significant attention as anode conductive materials for lithium-ion batteries. Conductive materials facilitate the movement of electrons between active materials, which determine the battery's capacity. Carbon nanotubes, when used as a conductive material, offer higher surface area and conductivity than conventional carbon black materials. In other words, the capacity and lifespan of the battery can be improved by reducing the amount of conductive material used and increasing the amount of active material input.

Professor Ahn Gwang-jin stated, “We were able to achieve great results through collaboration with various universities and institutions,” and announced follow-up research plans, saying, “We plan to conduct economic and environmental evaluations to determine the possibility of scaling up the process and implementing it industrially.”

Professor Seo Myung-won of Seoul City University said, “Unlike existing carbon nanotube production methods, this research is different in that the gases produced through the pyrolysis of solid waste such as masks can be utilized without a separate separation process,” and predicted, “This achievement will become a key technology in environmental aspects and various advanced industries.”

Professor Lee Kyung-jin of Chungnam National University said, “This study will be a new milestone for future research on upcycling and utilizing waste plastics.” He added, “Using carbon nanotubes as battery conductive materials can significantly improve battery capacity, and the fact that this process can be produced from waste plastics will have significant ramifications.”

This research was supported by funding from the Ministry of Trade, Industry and Energy's Materials and Components Technology Development-Strategic Core Materials Self-Reliance Technology Development Project and the Korea Research Foundation's Leading Research Center Group Research Project (ERC) funded by the Ministry of Science and ICT. The research was featured on the cover (Outside Back Cover) of Green Chemistry, a leading international journal in chemistry and the environment published by the Royal Society of Chemistry. It was published online on September 11, and the research results have been patented.

This study was jointly conducted by Professor Ahn Kwang-jin of UNIST, Professor Lee Kyung-jin of Chungnam National University, and Professor Seo Myung-won of Seoul City University, and provided technical support through the participation of Dr. Ra Ho-won's research team at the Korea Institute of Energy Research, Dr. Park Young-soo's research team at the Korea Carbon Industry Promotion Agency, Dr. Lim Ji-seon of the Korea Research Institute of Chemical Technology, and CEO Kang Deuk-ju of J.O.