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

• Published in: Journal of power sources 2012-01, Vol.197, p.276-284
• Main Authors: Nobili, F., Croce, F., Tossici, R., Meschini, I., Reale, P., Marassi, R.
• Format: Article
• Language: English
• Subjects: Aliovalent doping; Applied sciences; Cobaltite cathodes; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrochemical impedance spectroscopy; Exact sciences and technology; Li-ion batteries; Materials; Sol–gel synthesis
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2011.09.053

► Composite cathodes made of Zr-doped LiCoO2 with the addition of inactive Mg and Zr oxides. ► Mg and Zr oxides inhibit the aggregation of the active material particles. ► Dopant Zr enhances electronic conductivity and structural stability of the cathode. ► Mg and Zr oxides increase high-voltage stability of electrode–electrolyte interface. The complex sol–gel technique is applied to the preparation of Mg-/Zr-doped LiCoO2 cobaltites. The synthesis 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 chronopotentiometry 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.