Preparation method of fluorine-doped lithium-rich manganese-based positive electrode material

Abstract

The invention discloses a preparation method of a fluorine-doped lithium-rich manganese-based positive electrode material. The lithium-rich manganese-based positive electrode material has a chemical general formula of xLi2MnO3.(1-x) LiMO<2-y>F<2y>, wherein x is larger than or equal to 0.1 and smaller than or equal to 0.9, y is larger than 0 and smaller than or equal to 0.05, and M is one or more of Ni, Co, Mn, Cr, Fe, Ti, Mo, Ru, V, Nb, Zr and Sn. The preparation method comprises the following steps of: preparing a fluorine-doped lithium-rich manganese-based precursor through a precipitation reaction by adopting soluble metal salt, a precipitator, a soluble fluorine-containing compound and water; and uniformly mixing the fluorine-doped lithium-rich manganese-based precursor with a lithium salt, and carrying out presintering and high-temperature sintering to obtain the fluorine-doped lithium-rich manganese-based positive electrode material. According to the method, the soluble fluorine-containing compound is used as a fluorine source, fluorine doping is synchronously realized during coprecipitation of the lithium-rich manganese-based precursor, the doping uniformity is relatively good, and the cycle performance of the doped lithium-rich material is greatly improved.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a preparation method of a fluorine-doped lithium-rich manganese-based positive electrode material. Background technique [0002] Lithium batteries are gradually used in all aspects of human life due to their light weight, high energy density, and no pollution. As the range of applications expands, the performance requirements of Li-ion are also getting higher and higher. [0003] Energy density is one of the key factors currently restricting the development and application of lithium-ion batteries, and the specific capacity of cathode materials has become one of the main factors affecting the energy density of lithium-ion batteries. [0004] The current commercialized high specific capacity cathode materials are mainly ternary materials, and their specific capacity is still less than 200mAh / g. Lithium-rich manganese-based cathodes have attracted extensive attention from man...

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Problems solved by technology

[0008] The solid-phase mixing process is simple and can be mass-produced industrially, but the particle size of the raw materials is mostly above the micron level, the mixing uniformity is poor, and it is difficult for the product to achieve atomic-level mixing

[0009] The sol-gel method is to dissolve a variety of raw materials (transition metals, lithium sources, fluorine sources) to form a sol, heat and stir to gradually evaporate to dryness, and then sinter to obtain fluorine-doped lithium-rich manganese-based materials (Electrochimica Acta 105 (2013) 200-208 , patent application CN105895903A), its doping uniformity is better than that of solid phase mixing, but the process cost is high and it is difficult to realize industrial application

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