Carbon Coating and Zn2+ Doping of Magnetite Nanorods for Enhanced Electrochemical Energy Storage

ABSTRACTZn2+-doped magnetite (Fe3O4) nanorods with carbon coating of controllable thickness (Zn-Fe3O4@C) were prepared from lab-made Zn2+-doped Fe2O3 nanorods which were simultaneously coated with and reduced by carbon during the carbonization process using pyrrole as the carbon precursor. The as-prepared Zn-Fe3O4@C nanocomposites were evaluated as anode materials for lithium-ion batteries (LIBs). The results show that the Zn-Fe3O4@C nanorods with 2.5 mol% Zn2+ doping demonstrated a reversible capacity of 949.1 mAh g−1, compared to only 315.4 and 235.5 mAh g−1 for Fe2O3 and Fe3O4@C nanorods, respectively, after 60 cycles at a current density of 100 mA g−1. The Zn-Fe3O4@C nanocomposite electrodes also exhibited better cycling and rate performances than the corresponding Fe2O3 and Fe3O4@C nanorods. The superior performances witnessed in Zn-Fe3O4@C are attributed to the Zn2+ doping and the carbon coating, which have efficiently enhanced the electrical conductivity and lithium ion diffusion.