Polyethylene (PE) is one of the most widely used plastics, and vast amounts of waste PE are either buried or incinerated, leading to environmental concerns. Significant research efforts have focused on converting waste PE into carbon materials, particularly as carbon anodes for lithium-ion batteries (LIBs). However, most previously developed PE-based carbon anodes have underperformed compared to graphite-based commercial anode materials (CAM). In this study, LIB anode materials were prepared based on both commercial high-density polyethylene (CPE) and waste high-density polyethylene (WPE). Through thermal oxidative stabilization and high-temperature graphitization, both CPE and WPE were successfully transformed into highly crystalline carbon materials comparable to CAM. However, despite the high crystallinity, both CPE and WPE derived carbon contained significant number of fine particles and exhibited a broad particle size distribution. When used as an anode for LIBs, fine particles led to unwanted side reactions, resulting in an initial coulombic efficiency (ICE) of around 85%, which is lower than the ICE value of 92.5% observed in CAM. To tackle the low ICE problem, recarbonization after coal tar (CT) coating was adopted as a mean to induce secondary particle formation. After CT coating, the average particle size increased, and the size distribution became narrower. Although CT coating reduced the crystallinity slightly, the overall level remained comparable to that of CAM. As a result, the CT-coated graphitized CPE (GCPE@10CT) and CT-coated graphitized WPE (GWPE@10CT) exhibited performance comparable to CAM as LIB anodes, achieving an ICE of over 93% and a capacity of approximately 349 mAh g− 1.

Coal tar-coated artificial graphite anode derived from polyethylene for lithium-ion batteries
    Abstract 
    Graphical abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 Characterization
        2.3 Fabrication of lithium-ion battery cells
        2.4 Electrochemical characterization
    3 Results and discussion
    4 Conclusion
    Acknowledgements 
    References

• Heewon Jin(Department of Chemical Engineering, Myongji University, 116, Myongji‑ro, Cheoin‑gu, Yongin‑si, Gyeonggi‑do 17058, Republic of Korea)
• Dalsu Choi(Department of Chemical Engineering, Myongji University, 116, Myongji‑ro, Cheoin‑gu, Yongin‑si, Gyeonggi‑do 17058, Republic of Korea)
• Chelwoo Kim(Carbon Materials Research Cell, Research Institute of Industrial Science & Technology (RIST), Pohang 37673, Republic of Korea)
• Sei‑Min Park(Carbon Materials Research Cell, Research Institute of Industrial Science & Technology (RIST), Pohang 37673, Republic of Korea)
• Jung‑Chul An(Carbon Materials Research Cell, Research Institute of Industrial Science & Technology (RIST), Pohang 37673, Republic of Korea)
• Inchan Yang(Carbon Materials Research Cell, Research Institute of Industrial Science & Technology (RIST), Pohang 37673, Republic of Korea)