Selective Synthesis of Magnetite Nanospheres with Controllable Morphologies on CNTs and Application to Lithium‐Ion Batteries

Iron oxide is widely used in many areas due to its environmental friendliness, low cost, as well as unique intrinsic properties and the morphology is one of the important parameters determining the physical properties. In this work, Fe 3 O 4 nanospheres with different morphologies are synthesized on carbon nanotubes (CNTs) hydrothermally and by controlling the reaction conditions, solid, porous, and hollow Fe 3 O 4 nanospheres are conjugated with CNTs selectively and the three different structures are investigated as anode materials in lithium‐ion batteries. The morphology of Fe 3 O 4 is found to have a profound effect on the electrochemical performance of the lithium‐ion batteries under the same operating conditions. At high current densities, the hollow Fe 3 O 4 ‐CNT delivers the best electrochemical performance but at low current densities, the solid Fe 3 O 4 ‐CNT fares the best. The results provide insights into the design of high‐efficiency anode materials in lithium‐ion batteries.