High Rate Capability and Long Cycle Stability of Co3O4/CoFe2O4 nanocomposite As an Anode Material for High-Performance Secondary Lithium Ion Batteries

A facile and cost-effective urea-assisted autocombustion strategy has been designed for the fabrication of Co3O4/CoFe2O4 nanocomposite and pure CoFe2O4 anode materials followed by annealing at 700 and 900 °C for 6 h, respectively. To confirm the exact structure, Rietiveld analysis was performed on the Synchrotron XRD pattern of both the CoFe2O4 samples annealed at 700 and 900 °C. The results clearly depicts the formation of two phases (Co3O4:CoFe2O4) with the ratio of [76.3(5):23.6(3)%] in the sample annealed at 700 °C sample, while single phase CoFe2O4 formation was observed for the sample annealed at 900 °C. It has also been found that the designed nanocomposite sample is composed of small nanoparticles (50–100 nm), while the size of pure CoFe2O4 particles is in the range from 600 nm to 1 μm. When applied as an anode material, the obtained Co3O4/CoFe2O4 nanocomposite electrode exhibits high reversible capacity as well as excellent cycling stability and better rate capability in comparison to a pure CoFe2O4 electrode. The enhanced electrochemical performance of the nanocomposite can be attributed to the intimate interconnection between Co3O4 and CoFe2O4, along with the nanosize range of particles and high surface area, which not only favor fast kinetic properties facilitating electron transportation and Li+ ion insertion/deinsertion but also relieve the stress caused by volume changes during the numerous charge/discharge cycles and suppress the degradation of the material.