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A core-shell structure boron-doped precursor material, positive electrode material and preparation method

A core-shell structure and positive electrode material technology, applied in the field of lithium-ion battery materials, can solve the problems of increased cost and structure prone to collapse, and achieve the effect of avoiding collapse and reducing crystal transformation

Active Publication Date: 2022-03-11
ZHUJI PAWA NEW ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

CN103413931B discloses a boron-doped lithium-ion battery lithium-rich positive electrode material and its preparation method. The precursor is prepared by co-precipitation method, and then the precursor is calcined at high temperature together with boron source and lithium source to obtain a boron-doped positive electrode material, but it only achieves boron doping on the surface of the material, so the internal structure of the material is still prone to collapse during the long cycle
However, it requires special polymer materials, such as polyoxymethylene, aluminum tetrafluoroborate, and the metal oxides are nano-alumina, nano-magnesia, etc. The use of the above materials not only introduces a variety of organic compounds, but also increases the cost.

Method used

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  • A core-shell structure boron-doped precursor material, positive electrode material and preparation method
  • A core-shell structure boron-doped precursor material, positive electrode material and preparation method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Step 1. At room temperature, add nickel-cobalt-manganese sulfate (Ni:Co:Mn=0.83: 0.11: 0.06) with a concentration of 0.2mol / L to a 250mL round bottom flask, and stir vigorously at 800rpm for 0.5h;

[0032] Step 2: Continuously add 0.9 mol / L potassium borohydride dropwise into the flask at a constant speed, and continue stirring for 0.45 h. Then slowly add a small amount of potassium hydroxide solution to keep the pH of the solution at 9.5.

[0033] Step 3, wait for the color of the material to change to blue-green, and then stop the reaction after reacting for 0.5h. Filter and wash 3 times with deionized water to keep the pH of the solution at about 8.5.

[0034] Step 4. Place the wet precursor material prepared in Step 3 in an oven at 130°C and dry for 3 hours.

[0035] Step 5. Mix the material prepared in step 4 with the lithium source in a certain molar ratio, gradually raise the temperature to 750°C at a rate of 3°C / min, and sinter for 6 hours. After cooling, the ...

Embodiment 2

[0039] Step 1. At room temperature, add nickel-cobalt-manganese nitrate (Ni:Co:Mn=0.88: 0.09: 0.03) with a concentration of 0.4mol / L to a 500mL round bottom flask, and stir vigorously at 700rpm for 0.75h;

[0040] Step 2: Continuously add 2.2 mol / L potassium borohydride dropwise into the flask at a constant speed, and continue stirring for 0.9 h. Then slowly add a small amount of potassium hydroxide solution to keep the pH of the solution at 10.

[0041] Step 3: Wait until the color of the material changes to blue-green, and then stop the reaction after reacting for 1 hour. Filter and wash 3 times with deionized water to keep the pH of the solution at about 8.

[0042] Step 4. Place the wet precursor material prepared in Step 3 in an oven at 140°C and dry for 2 hours.

[0043] Step 5. Mix the material prepared in step 4 with the lithium source in a certain molar ratio, gradually raise the temperature to 850°C at a rate of 4°C / min, and sinter for 8 hours. After cooling, the p...

Embodiment 3

[0045] Step 1. At room temperature, add nickel-cobalt-manganese sulfate (Ni:Co:Mn=0.8: 0.1: 0.1) with a concentration of 0.5mol / L to a 250mL round bottom flask, and stir vigorously at 750rpm for 1h;

[0046] Step 2: Continuously dropwise add 2.8 mol / L sodium borohydride into the flask at a constant speed, and continue stirring for 1 hour. Then slowly add a small amount of sodium hydroxide solution to keep the pH of the solution at 10.5.

[0047] Step 3, wait for the color of the material to change to blue-green, and then stop the reaction after reacting for 0.5h. Filter and wash 4 times with deionized water to keep the pH of the solution at about 8.

[0048] Step 4. Place the wet precursor material prepared in Step 3 in an oven at 150°C and dry for 2.5 hours.

[0049] Step 5. Mix the material prepared in step 4 with the lithium source in a certain molar ratio, gradually raise the temperature to 800°C at a rate of 3°C / min, and sinter for 10 hours. After cooling, the positive ...

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Abstract

The invention belongs to the field of lithium ion battery materials, and specifically proposes a boron-doped precursor with a core-shell structure, a positive electrode material and a preparation method. The general chemical formula of the precursor material is M(BO 2 ) 2 @β‑M[(OH) 1‑x (BO 2 ) x ] 2 , the general chemical formula of the cathode material is Li 3 M(BO 3 ) 2 / LiCoO 2 @LiMO 2 / Li 3 M(BO 3 ) 2 , wherein M is Ni and Co, or Ni, Co and Mn. The positive electrode material of the present invention inherits the role of the metaborate in the precursor layer as a pillar, which can reduce the crystal transformation caused by lithium ion deintercalation during charge and discharge, avoid the collapse of the layered structure, and facilitate its structural stability; the core-shell structure The gradient change of boron in the medium is conducive to the directional migration of lithium ions, and the Li 3 M(BO 3 ) 2 / LiCoO 2 The hybrid shell is beneficial to reduce the contact between the high-nickel core and the electrolyte, and improve the cycle stability of the material.

Description

technical field [0001] The invention relates to the field of lithium-ion battery materials, in particular to a lithium-ion battery precursor material and positive electrode material, and in particular to a boron-doped precursor material and positive electrode material with a core-shell structure and a preparation method. Background technique [0002] As a new type of contemporary green energy, lithium-ion batteries have been widely used in electronic products, vehicles, large-scale energy storage power stations, aerospace and other related fields. Among them, layered nickel-rich ternary cathode materials (NCM, NCA) are considered to be one of the most promising cathode materials due to their high charge-discharge capacity, low cost, and low toxicity. However, this material has problems such as low initial Coulombic efficiency and easy collapse of the layered structure, which causes defects such as voltage plateau, fast capacity decay, and poor rate performance during the cyc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B35/12H01M4/505H01M4/525H01M4/62H01M10/0525
CPCC01B35/127H01M4/628H01M4/505H01M4/525H01M10/0525H01M2004/028H01M2004/021C01P2002/85C01P2004/03C01P2006/40Y02E60/10
Inventor 张宝王振宇
Owner ZHUJI PAWA NEW ENERGY