Introduced Iron‐Based Catalysts for Low‐Temperature Upcycling Regeneration of Spent Graphite towards Ultra‐Fast Lithium Storage Properties

Abstract Spent graphite, as the main component of retired batteries, have attracted plenty of attentions. Although a series of recycling strategies are proposed, they still suffer from high cost of regeneration and large CO 2 emission, mainly ascribed to the full‐recovery of surface and internal phase at ultra‐high temperature. However, the existing of suitable internal defects is conductive to their energy‐storage abilities. Herein, with the introduction of Fe‐based catalysts, spent graphite is successfully repaired at low temperature with the tailored surface traits, including conductivities, isotropy and so on. As Li‐storage anodes, all of samples can display a capacity of 340 mAh g −1 above at 1.0 C after 200 cycles. At high rate 5.0 C, their capacity can be also kept ≈300 mAh g −1 , and remained ≈233 mAh g −1 even after 1000 cycles. Assisted by electrochemical and kinetic behaviors, their cycling traits with dynamic surface transformations are detailed explored, including activated/fading mechanism, Li‐depositions forming etc. Moreover, the calculated constant time of as‐optimized regenerated sample is ≈3.0 × 10 −4 s, further revealing the importance of surface designing. Therefore, the work is expected to shed light on their energy‐storage behaviors, and offer low‐temperature regenerated strategies of spent graphite with high value.