Premium defect-enriched graphite from spent anodes of lithium ion batteries

Abstract

At present, responsible disposal of scrapped lithium-ion batteries (LIBs) is crucial to address the global issues of electronic waste. Herein, we propose an eco-friendly one-step technology to convert spent graphite (SG) in LIBs to nitrogen-doped defect-enriched graphite (NG) with an NH4Cl roasting strategy. This recycling technique does not require leaching by acids or water, and accordingly is free of any complicated separation processes. Detailed material analysis and experimental study demonstrated that our strategy not only removes most of the impurities in spent graphite, but also introduces extrinsic defects into the graphite matrix, leading to enhanced reversible Li+ storage and cycling stability. The NG delivers a remarkably improved reversible specific charge capacity of 455.9 mAh g−1 for the 1st cycle, and 452.1 mAh g−1 after 50 cycles at 0.1 A g−1 with nearly no attenuation, and also exhibits a desirable rate performance (a capacity of 175.3 mAh g−1 is achieved at 2 A g−1), in comparison to the SG and the commercial natural flake graphite (CG). This study offers a new viewpoint on the recycling technology of graphite anodes using in situ nitrogen doping for graphite, and meaningful progress toward the sustainable development of LIBs.