Sustainable Synthesis of a Carbon-Supported Magnetite Nanocomposite Anode Material for Lithium-Ion Batteries

Transition metal oxide magnetite (Fe3O4) is recognized as a potential anode material for lithium-ion batteries owing to its high theoretical specific capacity, modest voltage output, and eco-friendly character. It is a challenging task to engineer high-performance composite materials by effectively dispersing Fe3O4 crystals with limited sizes in a well-designed supporting framework following sustainable approaches. In this work, the naturally abundant plant products sodium lignosulfonate (Lig) and sodium cellulose (CMC) were selected to coprecipitate with Fe3+ ions under mild hydrothermal conditions. The Fe-Lig/CMC intermediate sediment with an optimized microstructure can be directly converted to the Lig/CMC-derived carbon matrix-supported Fe3O4 nanocomposite sample (Fe3O4@LigC/CC). Compared with the controlled Fe3O4@LigC material, the Fe3O4@LigC/CC nanocomposite provides superior electrochemical performance in the anode, which has inspiring specific capacities of 820.6 mAh g−1 after 100 cycles under a current rate of 100 mA·g−1 and 750.5 mAh g−1 after 250 cycles, as well as more exciting rate capabilities. The biomimetic sample design and synthesis protocol closely follow the criteria of green chemistry and can be further developed in wider scenarios.