A NCM ternary cathode material with hierarchical structure

Abstract

The invention relates to an NCM ternary cathode material with a special hierarchical structure, and belongs to the field of chemical energy storage batteries. A ternary cathode material precursor of nickel, cobalt and manganese is added to the deionized water with stirring, the pH value is controlled, and then a mixed metal salt solution and a mixed alkali solution are added dropwise under a protective gas atmosphere, so that the pH value is stabilized at 10-12, and control that feeding time and the reaction temperature to obtain the modify nickel-cobalt-manganese ternary cathode material precursor; Then the modified Ni-Co-Mn ternary cathode precursor and lithium salt were mixed and calcined evenly to obtain a NCM ternary cathode material with hierarchical structure. The compaction density, cyclic stability and magnification performance of the material are greatly improved.

Description

technical field [0001] The invention relates to a nickel-cobalt-manganese ternary positive electrode material with a special hierarchical structure, in particular to a method for preparing nickel-cobalt-manganese ternary positive electrode material by controlling the growth of the primary particles of the nickel-cobalt-manganese ternary positive electrode material precursor in a lithium ion battery. The invention relates to a positive electrode material, which belongs to the field of chemical energy storage batteries. Background technique [0002] With the continuous increase of people's demand for energy, secondary batteries have become the focus of people's attention. Lithium-ion secondary batteries have long cycle life, high and stable battery voltage, better cycle performance than other secondary batteries, fast charging and discharging without the memory effect of nickel-cadmium batteries, high battery specific capacity, Batteries are widely used in people's daily life...

AI Technical Summary

Problems solved by technology

At present, common special structure designs include linear fiber structure, sheet-like thin-layer structure, three-dimensional network structure, mesoporous structure and core-shell structure, etc. Although the mesoporous structure can significantly improve the rate performance of the material, the above-mentioned materials have the problem of low compaction density. In order to overcome the problem of compaction density, the core-shell structure material has the problem of phase separation, which seriously affects the later cycle of the material.

In order to overcome the phase separation problem, related research has synthesized a full concentration gradient material by designing complex preparation processes and equipment to reduce the phase separation problem, but the preparation process requires precise control of the synthesis steps and sintering steps, and additional equipment has been added. are not conducive to the realization of material commercialization

Not only that, in the process of preparing the nickel-cobalt-manganese ternary cathode material precursor by the traditional continuous co-precipitation method, there is no washing, drying and storage process in the preparation and use of the crystal nucleus. If the confluent aging process of the metal salt solution is interrupted, the preparation process of this batch of materials will end in failure, resulting in great waste

In addition, although studies have confirmed that the directional superposition of primary particles contributes to the thickening of {010} active crystal planes, and {010} active crystal planes help to improve the rate performance of materials, thickened active crystal planes can be formed by controlling the calcination conditions. The positive electrode material with oriented crystal planes can improve the rate performance of the material, but the morphology of the secondary particles of the material still cannot be maintained normally after the primary particles are oriented and stacked.

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