Lanthanum and magnesium doped high-nickel ternary lithium battery positive electrode material and preparation method

Abstract

The invention provides a lanthanum and magnesium doped high-nickel ternary lithium battery positive electrode material and a preparation method. A nickel source, a cobalt source and a manganese sourceare mixed with a lanthanum source and a magnesium source uniformly, then a precipitating agent and a chelating agent are added so as to prepare an NCM precursor paste, and the lanthanum doped high-nickel ternary cathode material Li<1.05-x>Mg<x>Ni<1-2y-z>Co<y>Mn<y>La<z>O<2> is synthesized through pre-sintering and sintering, wherein x is greater than 0 and is less than 0.05, y is greater than 0 and is less than or equal to 0.1, and z is greater than 0 and is less than or equal to 0.05. Through adoption of the high-nickel ternary lithium battery positive electrode material, the defect of low cycle stability of the traditional high-nickel ternary positive electrode material is overcome; lanthanum replaces cobalt and is doped in the lattice, and magnesium replaces lithium and is doped in thelattice, so that the doped lanthanum ions can effectively shorten the length of an axis c in the lattice and improve the ratio of an axis a to the axis c; the positive electrode material is synthesized and is guided to grow a better laminated structure, so that the material structure is more stable; and the doped magnesium impurity prevents cations from being arranged disorderly, so that the electrochemical performance of the positive electrode material is improved.

Description

technical field [0001] The invention relates to the technical field of lithium ion materials, in particular to a lanthanum-magnesium co-doped high-nickel ternary lithium battery positive electrode material and a preparation method. Background technique [0002] With the development of electric vehicles, lithium-ion batteries have become the main source of power for electric vehicles. There are various types, each with its own characteristics, and it will be difficult to be replaced by other power sources for a long time in the future. [0003] At present, the main research object of cathode materials for lithium-ion batteries is high-nickel ternary cathodes, whose main advantages lie in high capacity and stable low-temperature performance. However, as the content of nickel ions increases, the instability of the material increases. This is because during the synthesis of the positive electrode material, the content of Mn / Al ions as a skeleton support is less, and the overall...

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Problems solved by technology

[0007] However, the existing doping modification scheme does not disclose a scheme that can induce the synthesis of positive electrode materials to preferentially grow into a layered structure, so that the layered structure of the material is more stable and complete. Growth, making the layered structure of the material more stable and complete is of great significance for improving the cycle stability of traditional high-nickel ternary lithium batteries