Direct recycling of graphite from spent batteries and production scraps for the development of a circular and sustainable economy

Abstract Current lithium-ion battery recycling processes are based on high-temperature calcination (pyrometallurgy) or leaching treatments (hydrometallurgy), requiring huge amounts of energy and producing considerable waste. Direct recycling protocols are based on the reconstruction and regeneration of materials, eliminating the need for further material processing. In this paper, graphite electrodes have been recycled via a direct recycling protocol based on mild leaching with H 2 SO 4 and H 2 O 2 and calcination to eliminate the impurities and regenerate the structure. A Design of Experiments (DOE) has been proposed to determine the leaching conditions that reduce the generated waste and environmental impact, for which a Life Cycle Assessment (LCA) has been carried out. This combination of experimental and analytical methods has been useful to determine the parameters that have the greatest impact on the environment and select the most sustainable leaching condition, which, in this case, has shown a reduction of 36 % in acidification and 14 % in water use. The established recycling route has been validated with graphite anodes from production scraps and cycled cells (End-of-Life condition, EoL, SOH%<80 %), and in both cases, the polymeric compounds used in the electrode slurry preparation have been eliminated and the graphitization degree has been restored. These results show that graphite can be recycled from LIBs to develop a direct recycling route that promotes a sustainable circular economy and diminishes material waste. • Active materials have been recycled via Direct Recycling, maintaining their structure and avoiding pyro-and hydrometallurgy. • The process’s environmental impact was reduced after using a DOE for leaching optimisation while ensuring material readiness. • The proposed recycling process is suitable for electrodes from production rejects and cycled cells, without pre-processing.