The Performance And Synthesis Of Sherical And Non-sherical Li（Ni_xCo_yMn_z）O₂for Cathode Materials Of Lithium Ion Battery

Lithium ion batteries with high voltage, high capacity, pollution-free, no memory effect,self-discharge less,good circulation performance, and many other advantages is considered to be excellentperformance of a new generation of green high-energy battery. Positive lithium ion battery material is theimportant component of the positive and the properties of materials directly affect the lithium ion batteryperformance. At present the lithium ion battery development is rapid, and positive material is the key oflithium ion battery in research and development. Li ion battery anode materials Li(Ni_1/3Co_1/3Mn_1/3)O₂hasthe following advantages:1. high Reversible capacity;2.good circulation performance;3. High safety;4. Isfree from pollution to the environment etc. It is expected to be the best candidate materials for replacedLiCoO₂for the betteries, has become one of the hot spot in the research at present. Positive materialLi(Ni_1/3Co_1/3Mn_1/3)O₂in the process of preparation, Mn, Co, Ni three elements have a different nature, ifmanganese, cobalt, nickel three kinds of elements in accordance with the different proportion to syntheticmaterials, the preparation of the positive material will show the superiority of the different characteristics,such as the positive materials Li(Ni_0.8Co_0.1Mn_0.1) O₂, because nickel content increased, it will be showhigher high capacity, and low cost, but poor safety and cycle properties bad. This kind of positive materialsfor small appliances. The positive materials Li(Ni_0.5Co_0.2Mn_0.3)O₂,Co and Mn in greatly enhanced, and theincreasing of the cobalt content to2dlayer structure is more stable, the increase of the number ofmanganese content has improved security performance, not only improve circulation performance, andgreatly enhances the use of security, also give consideration to the high capacity, but cobalt high cost, it isapplicable to the power the power supply. The positive materials Li（Ni0.4Co0.2Mn0.4）O₂, microscopicstructure improvement and the improvement of the performance with preparation methods are inseparable,different preparation methods of the synthesized compounds in color, texture, the appearance, specificsurface area and electrochemical property have very big difference. So choose appropriate synthesismethod, through optimizing the synthesis process to improve the Li(Ni_1/3Co_1/3Mn_1/3)O₂performance,reduce cost, is still the key research in the future. Based on these ideas, this paper using three kinds ofelements on the different content to prepare positive materials, comparing with current commercial material, and then analyzes the structure of the material to influence on the performance of the battery, the mainresearch contents and conclusions are as follows:1, this paper firstly summarizes the current lithium ion battery positive materials research progress,mainly in three elements of positive materials and structure characteristics and existing problems of the fullinvestigation.2, this chapter discusses the application of second precipitation dry prepare Li(Ni_1/3Co_1/3Mn_1/3)O₂precursor,with material the spherical Li(Ni_1/3Co_1/3Mn_1/3)O₂, with this material and the commercial sphericalthree Li materials (Ni_1/3Co_1/3Mn_1/3)O₂to compared.3, the second total precipitation dry synthesis method to prepare positive materials Li(Ni_0.5Co_0.2Mn_0.3)O₂, discusses the preparation of precursor body temperature and reaction time to materials(Ni_0.5Co_0.2Mn_0.3)O₂. Because cobalt and Mn in greatly enhanced, and the increasing of the cobalt content to2dlayer structure is more stable, the increase of the number of manganese content has improved securityperformance, not only improve circulation performance, and greatly enhances the use of security, also giveconsideration to the high capacity, but cobalt high cost, applicable to the power the power supply.4, the second total precipitation dry synthesis method of preparation out battery materials(Ni_0.8Co_0.1Mn_0.1)O₂. Due to improve the nickel content so greatly enhance the specific capacity materials,reduce the content of the cobalt and lower the cost of materials, the material has specific capacity high,circulation performance is excellent, high temperature storage performance is good, etc. And thecommercial spherical material than the spherical material has higher efficiency first discharge, highercapacity and voltage platform longer. This is mainly thanks to the spherical Li(Ni_0.8Co_0.1Mn_0.1)O₂lithiumlayer of cationic mix row of smaller, to material first charging and discharging efficiency and capacity andvoltage platform more small influence, so Li(Ni_0.8Co_0.1Mn_0.1)O₂to the positive terminal of the lithium ionbattery is mainly used in small household electrical appliances and large energy storage device.Li(Ni_0.5Co_0.2Mn_0.3)O₂, discusses the preparation of precursor body temperature and reaction time onmaterials（Ni0.5Co0.2Mn0.3）O₂the influence. Because Co and Mn in greatly enhanced, and the increasing ofthe cobalt content to2dlayer structure is more stable, but the cost of cobalt higher, apply to power thepower supply.5, the total precipitation second dry synthesis method of preparation out positive materials Li (Ni_0.4Co_0.2Mn_0.4)O₂, and through the XRD and charging and discharging methods the structure andproperties of the full characterization. Due to the increase of the number of manganese content reducedbattery cost and improve the circulation of the material performance, but also greatly improves the batteryuse security, also give consideration to the high capacity. The result is of the material to provide practicalguidance, both theoretical significance and application value. Li(Ni_1/3Co_1/3Mn_1/3)O₂, Li(Ni_0.8Co_0.1Mn_0.1)O₂,Li(Ni_0.5Co_0.2Mn_0.3)O₂, Li(Ni_0.4Co_0.2Mn_0.4)O₂four positive materials, using the four kinds of materialsrespectively with the corresponding commercial materials from the morphology, vibration and performanceof density contrast three aspects, this paper analyzes the structure of the material influence on theperformance of the battery, and draw the conclusion that the total precipitation, secondary drying outsynthetic preparation of the spherical material because of the mixing cationic lithium row smaller, the firstcharge and discharge capacity of the higher efficiency and conclusion.So it is necessary to analyze different valence precursors to positive body materialLi(Ni_0.5Co_0.2Mn_0.3)O₂synthesis influence, to improve the material of performance for both theoreticalsignificance and application value.