Dielectric, magnetic and electrochemical characterization of CoFe2O4 nanoparticles and their application as an anode material in Li-ion battery

Abstract

• Porosity of prepared nanoparticles decreases with annealing. • Cationic distribution from octahedral to tetrahedral site was found more. • Ferrimagnetic state was confirmed from the presence of two sextet patterns. • High value of discharge capacity for the electrode made up of CoFe 2 O 4 nanoparticles was observed. • 98 % of Columbic efficiency was observed during long cyclic processes. CoFe 2 O 4 nanoparticles with an average crystallite size of 35 nm were successfully synthesized by hydrothermal method. To illustrate the various physical and chemical properties of the nanoparticles various studies like TGA-DTA, XRD, SEM, TEM, FT-IR, Raman, Dielectric, Magnetic and Electrochemical properties were carried out. The sample annealed at 800 °C was employed to prepare the electrode for Li-ion battery. During cyclic processes of charging and discharging, the capacity of fading was observed after 1st cycle. On annealing the porosity of nanoparticles got reduced and the grain-to-grain contact area was increased. The good discharge capacity in the first reverse cycle revealed less porosity on the electrode, which facilitated the Li-ions to interact with the electrode to form Li 2 O. The electrochemical impedance analysis for fresh cell (before cycling) as well as after 50th cycles were performed. The flow of charge and diffusion of lithium ions to the working electrode were affected during cycling process and this was due to the formation of solid electrolyte interphase (SEI) on electrode.