| The layered nickel-rich LiNiO2-based cathode materials has several advantages, such as high capacity, good thermal stability, low cost and low toxicity, which is considered to be one of the most promising lithium-ion battery cathode material. However, the loss of capacity during cycling, insufficient rate capability and poor storage performance have seriously hindered its application in large scale. At first, this paper summarizes the development background and the working principle of lithium-ion battery, especially the advantages and disadvantages of LiNi0.8Co0.15Al0.05O2. Then we systematically studied the structure, morphology and electrochemical performance of LiNi0.8Co0.15Al0.05O2. The surface modification and preparation of core-shell structure were used to improve its electrochemical performance of LiNi0.8Co0.15Al0.05O2.The hydroxide precursor of LiNi0.8Co0.15Al0.05O2 was synthesized successfully by coprecipitation method. The effects of different factors on the structure and morphology of the precursor were investigated. The performance was characterized by XRD, SEM, EDX and so on. From the results, we can get that:at the temperature of 55℃, stirring at 600 rpm, the effects of pH value, stirring time and the ammonia alkali ratio on the morphology of precursor. When the pH value is 11, the ammonia alkali ratio is 1:1.5, the dispersion effect of precursor is good and the morphology tend to be spherical morphology.The LiNi0.8Co0.15Al0.05O2 was modified by surface coating, though the precursor of LiNi0.8Co0.15Al0.05O2 wss coated in coprecipitation method. It was made of core-shell structure, in which Ni0.8Co0.15Al0.05(OH)2 as the core, Ni1/3Co1/3Mn1/3(OH)2 as the shell. The effect of different pH values on the coating was researched. The coated cathode material was analysised through XRD, SEM, EDX, electrochemical testing. The results showed that, electrochemical performance can be improved through the modification.
|
PDF Full Text Request