The Synthesis And Application Research Of The Higer Specific Energy Of Li-ion Batteries Li-rich Materials

Lithium ion batterries are widely used in the human daily life and has became thepower source for the new generation of electric tools and electronic products due to thehigh energy density, working voltage, long life， environment friendly and otheradvantages. At present, the development of higher specific capacity cathode material hasbecome a research hotspot. Li-rich manganese based material has the priority of highdischarge specific capacity, low cost, which has caused the attention of the researchersand are considered to be one of the candidate of the next generation of lithium ion batterycathode material. However, the drawbacks, such as, poor electronic conductivity, lowinitial discharge efficiency and the poor cycle performance has limited the use ofmaterials in experimental research as well as the industrial application. In this paper, onthe one hand, experiment of optimizing the synthetic process and modification of thematerials, was carried out to improve their electrochemical properties; On the other hand,from the perspective of the battery manufacture, basic battery related data was collectedto promote the commercialization of these materials.Firstly, The precursor materials had been synthesized by the co-precipitate method,Li-rich material Li [Li0.17Ni0.17Co0.10Mn0.56] O2was synthesized by optimizing thematerial distribution of li-ion, sinter temperature. Li [Li0.17Ni0.17Co0.10Mn0.56] O2material sintered at850℃hadthe better crystallization performance and had theminimum impedance of the SEI membrane and such materials based coin cell possessedfine cycle performance and lower initial irreversible. When the charge-discharge ranges2-4.6V (0.05C,1C=250mA.g-1),after50cycles the discharge capacity retation was88%,the initial charge capacity and the discharge capacity of the cell were298.1mAh g-1and256.1mAh g-1respectively. And then the as-prepared Li-rich oxide material was coatedby LiCoPO4. Because the process is simple and the LiCoPO4is the material that has theelectrochemical activity, both the cyclic performance and the high-rate capability of Li[Li0.17Ni0.17Co0.10Mn0.56] O2were obvious increased by coating LiCoPO4. Further studyshowed the structure of the LiCoPO4is stable, and LiCoPO4isolated directly contactbetween the Li-rich materials and the electrolyte effectively and prevented Li-richmaterials from reacting with the electrolyte, which leads to improve of theelectrochemical properties. Lastly the battery used the Li-rich materials produced more gases and the component of the gases were oxygen.,the electrochemical performance ofthe battery indicated that the Li-rich cathode material still needs further research to makesure they can be used in li-ion battery in future.