Preparation method of high-voltage positive electrode material with core-shell structure

Abstract

The invention discloses a preparation method of a high-voltage positive electrode material with a core-shell structure. The preparation method comprises the following steps of (1) ultrasonically dispersing a nickel source, a manganese source and a lithium source in an organic solvent, stirring and dissolving to form a solution containing nickel, manganese and lithium, (2) ultrasonically dispersing the ternary positive electrode material in an organic solvent, then gradually adding the nickel-manganese-lithium-containing solution into the ternary positive electrode material solution, stirring, heating and evaporating to dryness to obtain a powder precursor, (3) drying the powder precursor, heating and sintering in an oxidizing atmosphere, and cooling to obtain a sintered material, and (4) carrying out electric activation treatment on the sintered material to obtain the high-voltage positive electrode material with the core-shell structure. The preparation process is simple and easy to implement, and the prepared high-voltage positive electrode material has the advantages that the structure is stable, the coating layer is not easy to peel off, and the electrochemical performance under high voltage is good.

Description

technical field [0001] The invention belongs to the field of battery materials, in particular to a preparation method of positive electrode materials. Background technique [0002] At present, the positive electrode materials used for lithium-ion batteries mainly include lithium cobaltate, nickel-cobalt lithium manganate ternary material, lithium manganate and lithium iron phosphate. Lithium-ion batteries have been widely used because of their excellent performance such as high voltage, high capacity, high cycle, and good thermal stability. With the development of science and technology, people modify various positive electrode materials through modification technology in order to obtain better electrochemical performance. Due to the excellent safety of ternary materials, there is no problem of structure collapse after deep discharge of lithium cobaltate, and the price is cheap, it has been paid attention in recent years. In the field of high voltage, the current problems ...

AI Technical Summary

Problems solved by technology

In the double-layer coating process, the ternary material is directly added to the lithium, nickel, and manganese salt solution, stirred and then dried. The ternary material will have side reactions directly in the mixed salt solution, especially for high-nickel materials. In addition, The dispersion effect is not good after direct addition, resulting in uneven coating in the later stage, and even affecting the performance of the material

[0005] Under high voltage (especially above 4.4V), as the number of cycles increases, secondary ions or agglomerated single crystals may appear pulverization at the primary particle interface or separation of agglomerated single crystals in the later stage, resulting in increased internal resistance and attenuation of battery capacity It will be very fast, and the high temperature cycle is also prone to diving

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