Exploring the potential of iron oxide nanoparticle embedded carbon nanotube/polyaniline composite as anode material for Li-ion cells

Transition metal oxides are being widely explored to meet the requirements of high-capacity anodes for Li-ion batteries in electric and hybrid electric vehicles. Depending on the energy storage mechanism, anode materials are classified into insertion, conversion, and alloying types. Iron oxide (Fe2O3) is a conversion-type anode material for Li-ion cells. It has drawn significant attention due to its high specific capacity (1007 mAh g(-1)), environmental friendliness, and the availability of simple synthesis routes. In this study, attempts are made to improve the electrical conductivity and structural stability of Fe2O3 nanoparticles by embedding them in functionalized carbon nanotubes (F-CNT)/polyaniline (PANI) network, and the resulting nanocomposite has been studied as anode material for Li-ion cells. This composite anode material is synthesized using a simple hydrothermal method and in-situ-polymerization technique. Cells assembled with Fe2O3/F-CNT/PANI as anode against Li metal in half-cell configuration are found to offer an initial discharge capacity of 1633 mAh g(-1) and charge capacity of 353 mAh g(-1). After 50 cycles of operation, the discharge and charge capacities are 155 mAh g(-1) and 130 mAh g(-1,) respectively, with a Coulombic efficiency of 84% and capacity retention of 37%. Anode failure mechanism for the observed capacity fading is studied using post-mortem analysis.