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A kind of positive electrode active material and its preparation method and lithium secondary battery

A positive electrode active material and secondary particle technology, applied in secondary batteries, battery electrodes, circuits, etc., can solve problems such as uneven lithium deintercalation state, battery capacity attenuation, etc.

Active Publication Date: 2022-03-04
HUAWEI TECH CO LTD
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Problems solved by technology

[0004] In view of this, an embodiment of the present invention provides a positive electrode active material. By forming a closed-pore structure inside the primary particle, the closed-pore structure can effectively release the anisotropic volume change of the layered positive electrode active material during the charging and discharging process of the battery. The internal stress maintains the integrity of the primary particle structure, thereby ensuring that the secondary particles do not break, so as to solve the problems caused by the inhomogeneous lithium deintercalation state and the anisotropic volume change of the existing positive electrode active materials during the charging and discharging process. A large stress is generated inside the primary particle, which causes nano-cracks to form inside the primary particle, which in turn causes secondary particle breakage and leads to battery capacity attenuation.

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  • A kind of positive electrode active material and its preparation method and lithium secondary battery
  • A kind of positive electrode active material and its preparation method and lithium secondary battery
  • A kind of positive electrode active material and its preparation method and lithium secondary battery

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[0048] Correspondingly, an embodiment of the present invention also provides a method for preparing the above positive electrode active material, including the following steps:

[0049] S101. Mix the metal salt and hydrophilic nanoparticles to prepare a mixed solution, so that the hydrophilic nanoparticles are uniformly dispersed in the mixed solution, and the metal ions in the metal salt are in the hydrophilic nanoparticles surface adsorption;

[0050] S102. Add an alkaline material to the mixed solution, make the metal ions use the hydrophilic nanoparticles as nucleation points, and co-precipitate to obtain a positive electrode active material precursor, and the hydrophilic nanoparticles are evenly distributed in the Inside the positive electrode active material precursor;

[0051] S103. Uniformly mix the precursor of the positive electrode active material with the lithium salt, and perform heat treatment in an oxidative atmosphere to obtain the positive electrode active ma...

Embodiment 1

[0067] A kind of nickel cobalt lithium manganese oxide LiNi 0.6 co 0.2 m 0.2 o 2 (NCM622) The preparation method of ternary cathode active material, comprises the steps:

[0068] S101. Add acetylene black with an average particle size of 30nm-45nm into concentrated nitric acid, heat under reflux to 80°C for oxidation treatment for 12 hours, modify the surface of the inert acetylene black with hydrophilic oxygen-containing functional groups, and redisperse in the In water, obtain acetylene black aqueous dispersion liquid, wherein, the concentration of acetylene black nanoparticles is 0.1g / L; Nickel sulfate (NiSO 4 ), cobalt sulfate (CoSO 4 ), manganese sulfate (MnSO 4 ) according to the ratio of molar ratio Ni:Co:Mn=6:2:2 is added in the described acetylene black water dispersion liquid, is configured into the metal salt solution that metal ion total concentration is 2mol / L; And the ammonia of configuration 5mol / L aqueous solution and 10mol / L sodium hydroxide solution;

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Abstract

An embodiment of the present invention provides a positive electrode active material, including secondary particles formed by densely packing a plurality of primary particles, the interior of the primary particles includes closed pores, the size of the closed pores is in the range of 1nm-300nm, and the primary particles contain the compound Li c Ni a co b m 1‑a‑ b o 2‑d x d , wherein, M is selected from one or more of Mn, Al, Na, Mg, Ca, Zr, Sr, Ti, Cr, V, W, Si, Ga, Sn, lanthanides and actinides, and X is selected from From one or more of B, F, Cl and S, 0≤a≤1, 0≤b≤1, 0.8≤c≤1.5, 0≤d≤0.5. The closed pores inside the primary particles of the positive electrode active material can effectively release the internal stress caused by the volume change of the material during the lithium intercalation and deintercalation process, and improve the cycle stability of the positive electrode active material. The embodiment of the present invention also provides a preparation method of the positive electrode active material and a lithium secondary battery.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of lithium secondary batteries, in particular to a positive electrode active material, a preparation method thereof, and a lithium secondary battery. Background technique [0002] With the development of mobile terminals, especially electric vehicles, the development of lithium-ion batteries with high energy density to meet consumers' demands for long battery life has become a current priority. Based on this, researchers use positive and negative active materials with high specific capacity and increase discharge voltage to achieve the purpose of increasing energy density. [0003] Among them, nickel-cobalt lithium manganate (NCM) ternary cathode material is currently a practical high-capacity cathode material, such as figure 1 Shown is a schematic structural diagram of a conventional nickel-cobalt-manganese-manganese oxide (NCM) ternary positive electrode material. From a macrosco...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/525H01M4/505H01M4/485H01M10/0525
CPCH01M4/525H01M4/505H01M4/485H01M10/0525Y02E60/10
Inventor 夏威李阳兴王平华
Owner HUAWEI TECH CO LTD
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