Multi-walled carbon nanotubes composited with nanomagnetite for anodes in lithium ion batteries

Abstract

In this work, multi-walled carbon nanotube (MWNT) nanocomposites with homogenously anchored nanomagnetite of 10–20 nm prepared by a hydrothermal-annealing method have been demonstrated to serve as anode materials for lithium ion batteries (LIBs) with a specific capacity of 829 mA h g⁻¹ after 50 cycles at a current density of 100 mA g⁻¹ and a reversible capacity of 686 mA h g⁻¹ at a current density of 200 mA g⁻¹ for the nanocomposites with a weight ratio of 1 : 1, much larger than the specific capacity of 230 mA h g⁻¹ after 50 cycles at a current density of 100 mA g⁻¹ and a reversible capacity of 195 mA h g⁻¹ at a current density of 200 mA g⁻¹ for the MWNTs. The MWNTs in the nanocomposites could efficiently buffer the strain of volume change during lithiation/delithiation and greatly improve the electrical conductivity of the electrodes. The superior electrochemical performances of the Fe₃O₄/MWNTs were found to originate from the unique conductive network of the MWNTs in the nanocomposites as well as the high capacity from the nanomagnetite.