Estimation of recoverable resources used in lithium-ion batteries from portable electronic devices in Japan

Lithium-ion batteries (LIBs) are commonly used in portable electronic devices and are becoming increasingly popular worldwide in recent years. As LIBs are composed of several metals, secondary material recovery is vital in promoting sustainable resource use, but a statistical database on the amount and material information of LIBs consumed in Japan is not available. To develop a globally harmonized strategy for LIB recycling, this study estimates the recoverable resources used in LIBs from portable electronic devices in Japan. An analysis of LIB samples and estimated consumption amounts reveals that cobalt has been the most utilized resource of obsolete LIBs, but its usage has gradually decreased in recent years. Instead, nickel usage has increased in both obsolete and in-use LIBs, corresponding to the trend changes of cathode materials. Moreover, the amounts of copper, lithium, manganese, and fluorine steadily increased with the increase in LIB usage. Our results also illustrate the effectiveness of environmental labels in collecting LIBs and separating them into cobalt-rich or nickel-rich groups. We applied a vacuum heat treatment to the LIBs and found that this pretreatment is effective in inactivating LIBs. This study evaluates the LIB waste collection rate in Japan and discuss the challenges behind it. As the demand for sustainable resource use from discarded LIBs will increase in the future, this study will contribute to the development of strategies to continuously improve LIB recycling and resource recovery.