Multi-element in-situ co-doped ternary material precursor as well as preparation method and application thereof

Abstract

The invention discloses a multi-element in-situ co-doped ternary material precursor as well as a preparation method and an application thereof. The chemical formula of the precursor is (NixCoyMnz)(1-a-c)MaNc(OH)(2+k), wherein x is larger than or equal to 1 / 3 and smaller than or equal to 0.9, y is larger than 0 and smaller than or equal to1 / 3, z is larger than 0 and smaller than or equal to 0.4, the sum of x, y and z is 1, a is larger than or equal to 0.0001 and smaller than or equal to 0.01, and c is larger than or equal to 0.0001 and smaller than or equal to 0.01; radius of a doped ion M is close to that of the lithium ion, and M is selected from one or more of Mg<2+>, Zn<2+>, Zr<4+>, Nb<5+>, Ta<4+>, In<3+>, Sc<3+>, Y<3+>, Ce<4+> and Gd<3+>; radius of a doped ion N is close to that of metal ions Mn and Co in the ternary material, and N is selected from one or more of Al<3+>, Ti<4+>, Ge<4+>, W<6+> and V<5+>. In the preparation process of the ternary material precursor, two kinds metalions with different radii are introduced in situ, so that the doped metal ions are uniformly distributed in a precursor phase, and uniform mixing on the atomic grade is realized. The two kinds of metal ions with different radii are doped in different positions, cell parameters have coordinated variation, so that not only can a lithium ion transmission channel be expanded, but also good lattice structure of the ternary material can be kept, and the ternary material with excellent electrochemical performance is obtained.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery electrode materials, and in particular relates to a multi-element in-situ co-doped ternary material precursor, a preparation method thereof, and an application thereof in preparing a lithium-ion battery ternary positive electrode material. Background technique [0002] At present, the commonly used and developed cathode materials for lithium-ion batteries mainly include lithium cobalt oxide (LiCoO 2 ), lithium nickelate, lithium manganate (Li x mn 2 o 4 ), lithium iron phosphate (LiFePO 4 ), etc., a lot of basic research has been carried out at home and abroad and industrialization has been basically realized. Compared with the traditional positive electrode materials mentioned above, the layered lithium nickel cobalt manganese oxide positive electrode material (hereinafter referred to as "ternary material" or "NCM") better combines the advantages of lithium cobalt oxide, lithium n...

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Problems solved by technology

[0003] However, ternary materials also have some problems that need to be overcome: (1) The crystal structure of the material is unstable, and the crystal structure is easy to change during charging and discharging; (2) The surface structure of the material is unstable, and the compatibility between the material and the electrolyte is poor , due to LiPF 6 The electrolyte contains HF to corrode the electrode material, resulting in the dissolution of transition metal ions; (3) Ni 2+ Radius and Li + have similar radii, so Ni 2+ Very soluble in Li + Occupy each other, resulting in the occurrence of cation mixing phenomenon, Ni 2+ in Li + layer not only reduces the discharge specific capacity, but also hinders the Li + Diffusion of the structure, the disordered state of this structure directly deteriorates the electrochemical performance of the material; (4) The thermal stability of the ternary material is poor; (5) The compaction density of the material needs to be further improved

[0006] However, in the method of doping and modifying ternary materials mentioned above, on the one hand, it is difficult to ensure that the dopant ions are evenly distributed in the bulk phase of the ternary material; ions, resulting in disproportionate changes in the unit cell parameters of ternary materials, resulting in lattice deformities, it is difficult to ensure that the performance of ternary materials is greatly improved or enhanced

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