Electrothermal Coupling Enables Defect‐Targeted Topological Repair for Rapid Graphite Upcycling

ABSTRACT Spent graphite (SG) from end‐of‐life lithium‐ion batteries suffers from persistent structural disorder, yet the defect chemistry governing its regeneration remains poorly understood. Here, we identify carbon vacancies and quasi‐sp 3 topological defects as the dominant degradation motifs and leverage this insight to devise a defect‐targeted regeneration strategy. Under electrothermal coupling enabled by flash Joule heating in a CoCl 2 molten‐salt medium, cobalt species are selectively directed to defect sites, where strong Co‐defect interactions reduce the energy barrier for topological reconstruction. The resulting Co‐induced charge redistribution activates quasi‐sp 3 ‐carbon via population of π * antibonding states, while thermally assisted and field‐directed carbon migration promotes its conversion into a more ordered sp 2 ‐rich lattice. Concurrently, residual interphases and impurities are eliminated, lattice stress is relieved, and the cobalt catalyst is efficiently recovered. The regenerated graphite (RG) delivers a capacity of 257 mAh g −1 after 1000 cycles at 1 A g −1 , corresponding to 83% retention relative to the post‐activation capacity, and outperforms commercial graphite under identical conditions. This work establishes a chemically informed route for the rapid upcycling of SG through defect‐selective topological repair.