Sol–gel synthesis and electrochemical characterization of Mg-/Zr-doped LiCoO2 cathodes for Li-ion batteries

The complex sol–gel technique is applied to the preparation of Mg-/Zr-doped LiCoO2 cobaltites. The syn- thesis results in composite powders in which the cathodic material is intimately mixed with inactive metal oxides as Co3O4, MgO and ZrO2. Cycling ability of the electrodes is evaluated by chronopotentiom- etry at different currents and potentials, revealing an improved stability of the electrode surface for the Mg-/Zr-doped cathode. Kinetics is investigated by cyclic voltammetry and electrochemical impedance spectroscopy, revealing improvements both in bulk and interfacial transport properties. This behavior can be explained by the concomitant effects of Zr4+ doping and of morphology modifications induced by inactive MgO and ZrO2 oxides dispersion.