Nanoparticles of lithium cobalt oxide (LiCoO2) were synthesized by means of a citrate sol–gel combustion route. The particles were characterized by scanning and transmission electron microscopies (SEM and TEM), energy-dispersive X-ray spectroscopy, and X-ray diffraction (XRD) measurements. Near spherical nanoparticles of around 100 nm were observed in SEM and TEM micrographs. XRD data indicated that the as-prepared nanoparticles presented pure phase of LiCoO2 with R-3m symmetry. The kinetics of electrochemical intercalation of lithium into the nanoparticles were investigated by means of cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy (EIS) with special emphasis on the application potential as cathode material for aqueous rechargeable lithium batteries. CV studies of the nanoparticles at slow scan rate of 0.1 mV s−1 between 600 and 820 mV versus Ag/AgCl, demonstrated that the nanoparticles represented well-defined reversible peaks. The non-linear chemical diffusion of lithium into the nanoparticles was explored by EIS. In this regards, the results were discussed based on an equivalent circuit, distinguishing the kinetic properties of lithium intercalation. The kinetic parameters of lithium intercalation were obtained using the equivalent circuit, which were in good agreement with the experimental results. The changes of kinetic parameters of lithium intercalation with potential were also discussed in detail.
