Synthesis and electrochemical characterization of xLi(Ni_(0.8)Co_(0.15)Mg_(0.05))O_2-(1-x) Li[Li_(1/3)Mn_(2/3)]O_2 (0.0 ≤ x ≤ 1.0) cathodes for Li rechargeable batteries

摘要

Using solution based processing route, we have successfully synthesized xLi(Ni_(0.8)Co_(0.15)Mg_(0.05))O_2-(1-x) Li[Li_(1/3)Mn_(2/3)]O_2 (0.0 ≤ x ≤ 1.0) cathode materials for lithium rechargeable batteries. The phase formation behavior of these cathode materials is characterized by X-ray diffraction measurements. The Galvanostatic chargeedischarge characteristic of these cathodes is reported in various cut-off voltage limits. When these composite cathodes are charged to 4.8 V, electrochemical extraction of lithium takes place from active (Li[Ni_(0.8)Co_(0.15)Mg_(0.05)]O_2) as well as inactive (Li[Li_(1/3)Mn_(2/3)]O_2) components. Good cycleability of these cathodes is obtained when cycled in the cut-off voltage limits of 4.6-3.0 V. The cycleability of these cathodes are deteriorated when charged above 4.8 V and deep discharged up to 1.2 V followed by repeated cycling in these voltage limits. Based on the analyses of impedance spectra at various charge and discharge states, the probable reasons for such findings are discussed.