Flash Joule Heating Enabled Defect Healing and Graphite‐CNT Interfacial Fusion for Spent Graphite Upcycling

Abstract

The regeneration of graphite anodes from spent lithium‐ion batteries (LIBs) is essential for sustainable battery recycling. Existing strategies typically rely on energy‐intensive graphitization or hazardous chemical treatments, which are either ineffective in repairing intrinsic defects or environmentally unsustainable. Here, we show that spent graphite largely retains its graphitic framework and therefore requires selective healing of localized defects and removal of surface residues, rather than complete structural reconstruction. We develop an ultrafast thermal strategy using flash Joule heating (2273 K within 0.1 s, held for 10 s), which simultaneously repairs lattice defects and removes surface residues with minimal thermal budget. Moreover, carbon nanotubes (CNTs) are integrated into graphite and ultrafast thermal treatment enables interfacial fusion between CNTs and graphite domains, reconstructing long‐range conductive pathways across particles. This process transforms CNTs from passive conductive additives into active structural reconstruction agents. As a result, the regenerated graphite exhibits enhanced structural integrity and electron transport, delivering superior rate capability, cycling stability, and low‐temperature performance. In addition, the process suppresses thermal‐shock‐induced powder loss and significantly reduces energy consumption. This work establishes a mechanism‐driven strategy for defect‐selective healing and conductive‐network reconstruction in spent graphite, providing a promising and sustainable pathway for lithium‐ion battery recycling.