Synthesis and characterization of LiNi0.5Co0.2Mn0.3O2 as a cathode material for lithium ion batteries and investigating the effect of calcination temperature on electrochemical performance of cathode

In this study, LiNi0.5Co0.2Mn0.3O2 cathode material was synthesized by solid-state reaction. Li2CO3, NiO, Co3O4, and MnO2 were used as starting materials. In order to study the influence of heat treatment temperature on cathode synthesis, three heat treatment temperature 800, 850 and 900 ℃ were used. X-ray diffraction and scanning electron microscope equipped with EDX were utilized for sample characterizing. The efficiency of produced batteries was evaluated by charge-discharge tests. XRD results showed no impurity in the powders which synthesized in 800 ℃ and 850 ℃, however in 900 ℃ the impurity was detected. The intensity ratio of I003/I104 was used as a standard for degree of cation mixing. This parameter was 1.34 for the sample synthesized in 850 ℃. SEM analyzes reveal that samples which synthesize in 800 ℃ and 850 ℃ have homogeneous morphology with the average particles size of 0.5 and 0.7μm. However, the sample which synthesizes in 900 ℃ does not have homogeneous morphology and its average particle size is 1.5μm. The charge-discharge test in a voltage range 2.5-4.3 V and current rate 0.1C showed that the sample which synthesized in 850 ℃ had a discharge capacity of 147.15mAh/g and also this sample could save 88.4% of its capacity after 30 cycles.