High-nickel layered material with niobium-containing nano surface layer and preparation method of high-nickel layered material

Abstract

The invention discloses a high-nickel layered electrode material with a niobium-containing nano surface layer. The high-nickel layered electrode material is composed of an Nb<5+> gradient doped subsurface layer and a LiNbO3 / T-Nb2O5 composite surface coating layer, wherein the LiNbO3 / T-Nb2O5 composite surface coating layer is composed of two kinds of compounds, namely LiNbO3 and T-Nb2O5, the structure of the LiNbO3 / T-Nb2O5 composite surface coating layer is a structure (a) and / or a structure (b), the structure (a) is that T-Nb2O5 coats the surface of LiNbO5, and the structure (b) is that T-Nb2O5 and LiNbO3 are mixed to appear in the same layer; the concentration of Nb<5+> in the Nb<5+> gradient doped layer is gradually reduced from the particle surface to the inside, and in the LiNbO3 / T-Nb2O5 composite surface coating layer, the mass percent of T-Nb2O5 is 1 to 99 percent. According to the electrode material, the Nb<5+> gradient doped subsurface layer and the LiNbO3 / T-Nb2O5 composite surface coating layer are constructed; the problems of unstable surface structure and active lithium ion surface residue are effectively relieved, the reaction between the active material and the organicelectrolyte is inhibited, and the structural stability and the thermal stability of the material are remarkably enhanced, so that the rate, the cycle performance and the safety performance of a battery are obviously improved.

Description

technical field [0001] The invention relates to a high-nickel layered material with a niobium-containing nanometer surface layer and a preparation method thereof, belonging to the field of lithium battery electrode materials. Background technique [0002] High nickel layered transition metal oxide cathode material (LiNi 1-x m x o 2 , where M=Co, Mn, Al, etc., 0.6≤1-x≤1) has the advantages of high energy density, low cost, and relative safety. It has been applied in many fields such as electric vehicle power batteries, electric tool batteries, etc., and has become One of the most promising cathode materials for lithium-ion batteries. [0003] However, there are still inherent key technical problems to be solved urgently in high-nickel layered cathode materials. The first is the surface structure transformation and oxygen release reaction caused by cation mixing. The nickel content on the surface of high-nickel layered materials is high. When charged to a higher voltage (&...

AI Technical Summary

Problems solved by technology

Although lithium conductive coating has many advantages, the active lithium source is still introduced during the preparation process, and there is still the problem of removing active lithium residues

[0008] Therefore, for high-nickel layered materials, a single coating or doping effect is limited, and often cannot solve the problems of unstable surface structure and lithium residue at the same time. A novel material structure design and preparation method is needed to solve the above problems at the same time.

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