A kind of preparation method of nickel-cobalt-aluminum composite with multiple core-shell structure

Abstract

The invention provides a method for preparing a multiple core-shell structure Ni-Co-Al compound. The method comprises the steps of first synthesizing spherical Ni(OH)2; after D50 of Ni(OH)2 particles reaches 3 [mu]m, adding Ni-Co solution A1B1 and Al solution C1, Ni-Co solution A2B2 and Al solution C2, ..., Ni-Co solution AnBn and Al solution Cn with concentrations in change of gradient, and obtaining the multiple core-shell structure Ni-Co-Al compound NixCoyAl1-x-y(OH)3-x-y. According to the method, not only is the problem of difficulty of NCA synthesis of liquid-phase coprecipitation solved technically, but also synthesized NCA has multiple core-shell characteristics and has a chemical composition of step distribution, chemical compositions of adjacent areas of Ni-Co lithium aluminate anode material having undergone high-temperature sintering do not have obvious differences, composition differences between shells of ordinary core-shell materials and between the shell and the core are avoided; in the charge-discharge process, the volume change degree of each part of the particles is close, the shortcomings of ordinary core-shell structures are overcome, performance advantages of the shell components and core components are also retained, and an integral material has good cycle performance and thermal stability.

Description

technical field [0001] The invention relates to a preparation method of a battery material precursor, in particular to a preparation method of a lithium-ion battery anode material, in particular to a preparation method of a nickel-cobalt-aluminum compound with multiple core-shell structures. Background technique [0002] Lithium-ion batteries have been widely used in various fields such as science and technology, military affairs, and life. The cathode material occupies the most important position in the composition of lithium-ion battery products. The quality of the positive electrode material directly determines the final performance of the battery, and the positive electrode material accounts for about 40% of the battery cost. Currently commonly used lithium ion cathode materials are LiCoO 2 , LiNiO 2 , LiMn 2 o 4 , LiMPOx et al. LiCoO 2 It has the advantages of simple preparation process, stable performance, high specific capacity, and good cycle performance. Howe...

AI Technical Summary

Problems solved by technology

NCA cathode materials belong to the series of aluminum-doped nickel-cobalt cathode materials. Scholars at home and abroad have conducted research on them for more than ten years. However, due to the limitations of its difficult synthesis and complex process requirements, its large-scale commercial application has been constrained.

NCA materials have been silent for a while, but researchers are still unable to let go of the high specific capacity performance of NCA materials. The discharge specific capacity of 200mAh / g is still attractive in the environment of high power performance requirements.

Due to Al(OH) 3 Ksp=1.3*10 -33 with Co(OH) 2 Ksp=1.6*10 -15 and Ni(OH) 2 Ksp=2.0*10 -15 Compared with the difference of 1018 times, resulting in the co-precipitation of nickel-cobalt elements, the precipitation speed of aluminum ions is significantly faster than that of nickel-cobalt ions, so it is easy to form colloids or agglomerate flocs from ultrafine nano-floccules. During precipitation, the product is precipitated in a flocculent manner, which seriously affects the crystallinity of the material, thereby reducing the physical and chemical properties of the material

Images