Synthesis and electrochemical characterization of pillared layered Li1−2xCaxCoO2

The pillared layered Li1−2xCaxCoO2 has been obtained for the first time by a molten salt ion exchange reaction. The X-ray diffraction data of the materials show that they are single phase and retain the layered α-NaFeO2 type structure. The electrochemical testing of Li1−2xCaxCoO2 cells with an upper cutoff potential of 4.5 and 4.7 V (vs. Li+/Li) show that the specific capacity of the oxides have been increased, respectively, to 175 and 211 mAh g−1, and retain better charge-discharge cycling performance. The XRD data shows these improvements are attributed to the pillaring role of Ca2+ which helps to suppress unwanted phase transition.