Overview of the development trend of the hottest l

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Overview of the development trend of lithium battery materials technology

thanks to the development of new energy vehicles, power batteries are at the outlet of rapid development, and the development of new energy vehicles also constantly puts forward higher requirements for the performance of power batteries. The action plan for promoting the development of automotive power battery industry puts forward that by 2020, the specific energy of new lithium-ion power batteries will exceed 300wh/kg, and by 2025, To achieve the specific energy of the new system power battery unit of 500 WH/kg

driven by both policy and market, power batteries are bound to develop towards the current universal experimental machine with high energy density, high cycle performance and high safety performance, which requires research institutions and enterprises to make improvements in cathode materials, cathode materials and electrolyte. Solid state batteries, silicon carbon cathode, high nickel ternary materials and lithium rich manganese cathode are considered to be the mainstream technical routes for the development of enterprises in recent years

lithium rich manganese based cathode: ideal material with low precious metal content

the technical goal of single battery in 2025 is to achieve a specific energy of 400wh/kg. The development of more efficient and energy-saving new cathode materials to overcome and replace the existing defective cathode materials has become a research hotspot. Among the known cathode materials, the specific discharge capacity of lithium rich manganese based cathode materials is more than 250 MAH/g, which is almost twice the actual capacity of the commercialized cathode materials at present; At the same time, this material is mainly composed of cheaper manganese elements and less precious metals. Compared with the commonly used lithium cobalt oxide and nickel cobalt manganese ternary cathode materials, it is not only low-cost, but also safe. Therefore, lithium rich manganese based cathode materials are regarded as the ideal materials for the next generation of lithium power batteries

many enterprises, including dangsheng technology, jiangte electric and AVIC lithium, are stepping up the research and development of lithium rich manganese based cathode materials. The Institute of physics of the Chinese Academy of Sciences has improved the voltage attenuation of lithium rich manganese based positive pole cycle, reaching the target that the voltage attenuation drops to less than 2% after 100 weeks, and has made significant progress. The team of Peking University developed a lithium rich manganese based cathode with a specific capacity of 400mah/g for the first time, which can reach the goal of 400wh/kg

at present, there are still technical problems to be solved to realize the full application of lithium rich manganese based cathode, such as reducing the first irreversible capacity loss, improving the magnification performance and cycle life, and inhibiting the voltage attenuation in the cycle process

high nickel ternary materials: 2018 is the first year of development

according to the starting point research prediction, the output of nickel cobalt manganese in 2018 will reach 47gwh, an increase of 32% over last year, while the output of cobalt relying on domestic and foreign universities, research institutes, R & D centers and well-known enterprises lithium carbonate will only be 19gwh, an increase of 5% over last year. Constrained by the scarcity of cobalt and the continuous rise of cobalt price, battery enterprises actively promote the high nickel of ternary materials and reduce costs by reducing the proportion of cobalt in batteries. The cobalt molecular content of ncm811 is only 6.06%

nickel cobalt manganese materials have high energy density, stable electrochemical performance, high capacity, low cost and other advantages, and will gradually replace lithium iron phosphate and ordinary ternary batteries in the future. At present, enterprises such as dangsheng technology, Shanshan Co., Ltd. and beiteri have met the mass production conditions of ncm811, and 2018 is considered to be the first year of the development of high nickel ternary materials

solid state battery: solid materials replace diaphragms and electrolytes

all solid state battery is recognized as one of the mainstream directions of battery development in the next step in the industry and academia

on the one hand, all solid state battery technology is the only way for battery miniaturization and thin film. The volume of diaphragm and electrolytic 10 integral experimental machine or part liquid transported by parts together accounts for almost 40% of the battery volume. If the diaphragm and electrolyte are replaced with solid materials, the distance between the positive and negative electrodes can be shortened to a few microns, and the thickness of the battery can be greatly reduced

on the other hand, compared with ordinary lithium batteries, the energy density of all solid-state batteries is significantly increased, which can reach wh/kg, while lithium-ion batteries are generally wh/kg. High safety is also one of the important driving factors for the development of all solid-state batteries. From the perspective of safety, the traditional lithium battery electrolyte is an organic liquid, which will oxidize and decompose to produce gas at high temperature, which is prone to combustion, which greatly increases the insecurity. If solid materials are used to replace the electrolyte, the safety performance of the battery will be greatly improved

at present, the energy density of polymer solid-state batteries developed by Qingdao Energy Institute of Chinese Academy of Sciences can reach 300wh/kg, and the energy density of inorganic solid-state lithium batteries developed by Ningbo materials of Chinese Academy of Sciences can reach 240wh/kg. In addition, the institution is cooperating with Ganfeng lithium industry to promote its industrialization, and the products are planned to be mass produced in 2019. In the industry, battery leading enterprises including Toyota, Panasonic, Samsung, Mitsubishi, Ningde times, etc. have invested in research and development and launched the layout of solid-state batteries

solid state battery is undoubtedly one of the mainstream technical routes in the future, but there are still problems such as high cost, complex preparation process, immature technology, etc. the overall low rate performance of the battery, large internal resistance, large voltage drop during high rate discharge, unrealistic fast charging and other problems also need to be solved urgently. There is still a way to go to achieve large-scale commercialization

silicon carbon negative electrode: it will usher in an explosion in two to three years.

silicon carbon material is the most commercialized new high-energy density negative electrode material at present. Spir predicts that the silicon carbon material industry will really embark on the stage of lithium battery negative electrode materials in a large area in the second half of 2018, and will also usher in a major explosion in the next two to three years, with broad prospects for the industry

the ultra-high theoretical energy density of silicon carbon composites can significantly improve the specific capacity of monomers. In addition, it has the advantages of low lithium removal voltage and environmental friendliness. It is considered to be an ideal anode material to replace graphite in the next generation. With the development of new energy vehicles, the specific energy of power batteries continues to put forward higher requirements. In the future, graphite will gradually be replaced by silicon carbon cathode materials

as of December 2017, the top 8 domestic negative electrode material enterprises are basically increasing the expansion of silicon carbon material production capacity, and a number of new cross industry entrants are involved in the layout of silicon carbon negative electrode materials, and their new production capacity will start to be put into production in. BYD, Ningde times, GuoXuan high tech, beiteri, Shanshan Co., Ltd., Lishen, BIC, Wanxiang, etc. have all launched the layout of silicon carbon cathode materials, with the domestic sales of 288000 new energy vehicles in January (9)

although silicon carbon anode materials still have problems such as high cost, difficult technology and imperfect supporting industries, the prospect of large-scale application is still promising

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