Exploring the potential of graphite recycling and reuse for more sustainable lithium-ion batteries

To achieve more sustainable lithium-ion batteries (LIBs), it is crucial to minimize the dependence on critical resources by maximizing their successful recovery. This study focuses on the treatment of graphite extracted from used commercial LIBs, which is commonly simply burnt off or used as fuel for the recycling of the comprised metals, to enable its reuse in the production of new LIBs. After physical separation, however, graphite contains various impurities originating from the electrolyte, separator, and cathode. Subsequent acid and heat treatments effectively reduce the amount of these impurities without causing significant structural changes to the graphite itself. As a result, the developed process leads to a noteworthy enhancement in cycling stability. The thus treated reused graphite provides a reversible capacity of 358 mAh g$^{−1}$, along with an initial Coulombic efficiency (CE) of nearly 90%, i.e., values that are very well competitive with pristine graphite. When used in graphite‖NMC$_{622}$ cells, it delivers very good cycling performance with a capacity retention of 80% after more than 500 cycles. These findings highlight the potential of reusing graphite as a viable pathway for more sustainable LIBs.