Synthesis and electrochemical characterization on dual-doped LiCoO 2 via green chemistry method for lithium rechargeable batteries

LiCoO 2 and LiCu x Al y Co 1− x − y O 2 ( x = 0.05–0.15; y = 0.05–0.15) powders have been synthesized by sol–gel method using malic acid as chelating agent to obtain sub-micron sized particles. The synthesized samples have been subjected to spectral studies viz., differential thermal analysis (TG/DTA), fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX) and electrochemical characterization. XRD peak reflections of LiCoO 2 and LiCu x Al y Co 1− x − y O 2 exhibit high degree of crystallinity with better phase purity. SEM images of LiCoO 2 exhibit an ice cube surface morphology with grains size of 1.5 μm. Doped lithium cobalt oxide shows surface morphology of uniform particle size 2 μm. EDAX peaks confirm the actual composition of Cu, Al, Co and O in LiCoO 2 and LiCu x Al y Co 1− x − y O 2 . Charge–discharge studies of undoped LiCoO 2 synthesized by sol–gel method deliver maximum an initial discharge capacity of 127 mA h g −1 which corresponds to columbic efficiency of 65 % during the first cycle with capacity fade of 0.13 mA h g −1 cycle −1 over the investigated 10 cycles. Cu and Al doping LiCoO 2 exhibit the capacity fade of 0.06, 0.16, 0.14, 0.13 and 01.3 mA h g −1 cycle −1 over the investigated 10 cycles corresponding to columbic efficiency of 74, 75, 73, 73 and 71 with capacity fade of 2, 3, 2, 2, and 2 mA h g −1 cycle −1 at the 10th cycles for Cu: Al doping of 0.1:0.1, 0.13:0.07, 0.07:0.13, 0.15:0.05, and 0.05:0.15 respectively. Graphical Abstract