Research on power lithium ion battery cathode material

Source: 2020 - 04 - 12 clicks breasts: time power lithium ion battery for dynamic safety of lithium ion battery, to effectively solve the security problems, mainly from the following several aspects: the reasonable design the heating effect of the battery, effectively prevent heat control in the case of not reasonable use, and find the safety of the electrolyte and the anode material. With the dynamic large capacity lithium ion battery applications, its security problem such as short circuit, the craft is more and more prominent, this is a dynamic lithium-ion battery in the field of large-scale, many applications need to overcome a big problem. Dynamic lithium ion battery is explosive, edm, safety problems such as leakage, seriously hindered the dynamic progress of lithium ion battery in practical application. With the continuous development of new power lithium ion battery materials, safety performance is also a new progress. Therefore, how to develop and the preparation of new power lithium ion battery materials to improve the safety performance of power lithium ion battery is of great significance. 2. Lithium ion battery cathode material power lithium ion batteries commonly used anode material with lithium ion, lithium ion 2, nickel cobalt manganese lithium oxide, etc. Although these materials have the advantages of high capacity density, but its security is generally poor, there is a big security hidden danger. At present, the research has made great progress of new anode materials, mainly includes the following several aspects. 2. 1 lithium iron phosphate lithium iron phosphate theoretical capacity of 170 mah/g, charging and discharging voltage of 3. 5 volts. It is more widely than traditional lithium battery cathode material, cheaper and more environmentally friendly. The anode materials for lithium iron phosphate, high thermal stability, high safety and good cycle performance. Therefore, lithium iron phosphate can be used as a kind of very safe dynamic lithium ion battery materials. 2. 1. 1 the synthesis of lithium iron phosphate lithium iron phosphate synthesis method are many, shown in the table below, points out their advantages and disadvantages respectively. See table 1. 2. 1. 2 lithium iron phosphate modified lithium iron phosphate, while security, but also exist some fatal flaws, such as low electronic conductivity and ionic diffusion is slow, low volume energy density. These can affect the lithium iron phosphate is practical, need to be improved. Scholars have carried out extensive research, and has made great progress. ( 1) Add a conductive material in order to improve the conductivity of lithium iron phosphate, can join the conductive material. It can be coated with metal or carbon. In lithium iron phosphate coating or dispersed carbon can not only enhance conductivity between particles, reduce the polarization of the battery, you can also provide lithium iron phosphate electron tunnel to compensate the charge balance, thus become scholars [ 2] The modification methods of choice. Using the method of mechanical activation, under the protection of nitrogen, 10 hours through 600 degrees sintering synthetic coated lithium iron phosphate. Croce and others with 1% copper and silver coated lithium iron phosphate, by X-ray energy spectrum analysis, get the metal scattered around the lithium iron phosphate. Scattered in the metal lithium iron phosphate provides a conductive bridge, increase the conductivity between the particle and particle, increase the capacity of the lithium iron phosphate. ( 2) Although metal elements doping carbon and metal particles coating method to effectively change the conductivity between particles, but has no effect on lithium iron phosphate particles inside the electrical conductivity of. When lithium iron phosphate particle size is larger, it is difficult to get the current large, large capacity of products. Metal doping method, however, to a certain extent can lead to lattice defects, so you can adjust the electrical conductivity of materials. ( 3) The preparation of spherical lithium iron phosphate in order to achieve the high-energy lithium-ion batteries, battery materials with high density and specific capacity, but the density and particle morphology and particle size. If the shape is irregular, may be severe particle bridge. However, with the rules of the spherical particle filler can effectively avoid the contact area between particles caused by the small bridge phenomenon. Therefore, development of the spherical lithium iron phosphate cathode material is one of the effective methods to improve the packing density and specific capacity.