Method for aluminum cladding of positive electrode material by wet method, positive electrode material, positive electrode and battery

Abstract

The invention discloses a method for aluminum cladding of a positive electrode material of a lithium ion battery by a wet method. The method comprises the following steps of uniformly dispersing an aluminum-containing compound in a dispersing agent, heating the obtained mixture, adding an alkali additive by several times, and allowing constant-temperature reaction to obtain an aluminum-containing liquid; uniformly mixing a Ni-Co-Mn ternary positive electrode material with the dispersing agent, reducing a temperature, adding the aluminum-containing liquid, and allowing constant-temperature reaction; and finally, carrying out suction filtration, drying, tempering, sintering, cooling, smashing and sieving to obtain the aluminum clad positive electrode material. The invention also discloses the positive electrode material prepared by the method and a positive electrode and a battery which are prepared from the positive electrode material. The alkali additive is added into the aluminum-containing compound solution by several times to obtain the aluminum-containing intermediate liquid with fine particle size, so that aluminum is facilitated to be attached onto the positive electrode material; the aluminum-containing intermediate liquid is slowly added into a material system to obtain the positive electrode material with uniformly-clad aluminum; and the lithium ion battery prepared by using the positive electrode material has the advantages of better cycle performance and higher safety performance.

Description

technical field [0001] The present invention relates to a method for manufacturing positive electrode materials for lithium-ion batteries, in particular to a method for wet-coating aluminum with positive-electrode materials for lithium-ion batteries, and also to positive-electrode materials prepared by the method, as well as positive-electrode and Battery. Background technique [0002] In the application of lithium-ion battery cathode materials, LiCoO 2 With good cycle performance, LiNiO 2 With good specific capacity, LiMnO 2 It has low cost and high safety performance, and the layered nickel-cobalt-manganese ternary composite material LiNi x co y mn z o 2 (where x+y+z=1, 0<x, y, z<1), through the synergistic effect of Ni-Co-Mn, it can combine LiCoO 2 , LiNiO 2 , LiMnO 2 The advantages of these three materials enable the prepared lithium-ion battery to have high energy, good cycle and safety performance, and gradually become a research hotspot in the current l...

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Problems solved by technology

[0003] However, since the nickel-cobalt-manganese ternary composite material also has some inherent defects, the lithium-ion battery prepared by it also has some problems in practical applications, such as the phase change of the material under high pressure makes the cycle performance poor, and the material and The poor compatibility of the electrolyte can easily cause the structure of the material to collapse, the electronic conductivity of the material is low and the metal ions are easily mixed, resulting in poor rate performance, and the material is prone to high-temperature flatulence, etc., which limit the use of nickel-cobalt-manganese ternary composite materials in batteries. The bottleneck in application, many researchers have invested in the modification of nickel-cobalt-manganese ternary materials. The common method is to select some transition metal oxides or metal oxides to dope the positive electrode material and coat the surface of the positive electrode material with a inert metal oxide

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