An efficient recycling strategy to eliminate the residual 'impurities' while heal the damaged structure of spent graphite anodes

The recycling of graphite from spent lithium-ion batteries (LIBs) is overlooked due to its relatively low added value and the lack of efficient recovering methods. To reuse the spent graphite anodes, we need to eliminate their useless components (mainly the degraded solid electrolyte interphase, SEI) and reconstruct their damaged structure. Herein, a facile and efficient strategy is proposed to recycle the spent graphite on the basis of the careful investigation of the composition of the cycled graphite anodes and the rational design of the regeneration processes. The regenerated graphite, which is revitalized by calcination treatment and acid leaching, delivers superb rate performance and a high specific capacity of 370 mAh g−1 (∼99% of its theoretical capacity) after 100 cycles at 0.1 C, superior to the commercial graphite anodes. The improved electrochemical performance could be attributed to unchoked Li+ transport channels and enhanced charge transfer reaction due to the effective destruction of the degraded SEI and the full recovery of the damaged structure of the spent graphite. This work clarifies that the electrochemical performance of the regenerated graphite could be deteriorated by even a trace amount of the residual “impurity” and provides a facile method for the efficient regeneration of graphite anodes.