Electrochemical performance of layered Lico0.9X0.1O2 (X = Cr, Mn, Fe, Ni) cathode materials for lithium-ion batteries / Nor Syamilah Syamimi Mohd Abdillih

LiCoO2 is one of the main cathode materials used in commercial lithium-ion batteries due to the high rate capacity, high energy density and good life cycle. However, the LiCoO2 cathode material is high cost and toxic. Besides, this cathode material also suffers from a few limitations such as low thermal stability and structural degradation when charging at a higher voltage. Therefore, the search for better cathode material is needed to be developed to improve the performance of existing LiCoO2. One of the approaches is the substitution of LiCoO2 with transition metal which is cheaper and non-toxic that can enhance the structural stability and electrochemical properties. In this work, LiCo0.9X0.1O2 (X = Cr, Mn, Fe, Ni) prepared by self-propagating combustion (SPC) method using citric acid as a combustion agent were investigated. The precursors of LiCo0.9X0.1O2 were annealed at a temperature of 800 °C for 24 h. The materials were characterized using Simultaneous Thermogravimetric Analysis (STA), X-Ray Diffraction (XRD), Field Emission Scanning Electron Microcopy (FESEM), and Energy Dispersive X-Ray Spectroscopy (EDX). All the cathode materials found to be single and pure phase with no impurity peaks detected with the surface morphology of roughly polyhedral-type crystal with some spherical-type Finally, the electrochemical performance of the materials was studied using discharge cycling in the voltage range of 2.5 V to 4.2 V. Based on the results, the Mn substituted cathode material exhibited a better initial specific discharge capacity of 136.60 mAh/g. Different stoichiometries of LiCo1-xMnxO2 (x = 0.1, 0.2, 0.3, 0.4, 0.5) cathode materials has been further investigated. The initial discharge capacities of all the materials are 136.60 mAh/g, 112.66 mAh/g, 93.75 mAh/g, 66.98 mAh/g, 52.32 mAh/g, respectively. Therefore, only small amount of a Mn content is preferable to enhance the electrochemical performance of LiCoO2 layered cathode material.