Synthesis and electrochemical performance of tetravalent doped LiCoO2 in lithium rechargeable cells

Titanium-doped lithium cobalt oxides having the formula LiTixCo1-xO2 (0# < x# < 0.5) have been synthesized using high temperature solid-state technique and its performance in a lithium rechargeable cell is reported. The synthesized oxides were structurally analyzed using X-ray diffraction (XRD) and Raman spectroscopy. It has been observed that single-phase materials were below 10% of Ti doping whereas impurity spinel phases were detected at higher concentrations. Electrochemical behaviors of the prepared powders were analyzed using cyclic voltammetry (CV) and galvanostatic charge/discharge cycling studies in the voltage range 3.0-4.25 V (vs. Li metal) using 1 M LiClO4/PC as electrolyte. The composition with x = 0.01 exhibits an initial charge and discharge capacity of 157 and 148 mA h/g at 0.2C rate, respectively, as compared to 137 and 134 mA h/g of LiCoO2. Further, more than 90% of the capacity is retained even after 10 cycles. The role of tetravalent doping on the electrochemical behavior of LiCoO2 has not been reported previously.