A double-layer coating modified ternary positive high-nickel material and preparation method thereof

A double-layer coating and positive electrode technology, which is applied to electrical components, battery electrodes, structural parts, etc., can solve the problems of high residual alkali content, a large amount of gas and heat, and instability of materials, and improve the specific capacity of the first discharge. Improve the electrochemical stability performance, the effect of less demanding production equipment

Active Publication Date: 2021-06-22
TIANJIN GUOAN MGL NEW MATERIALS TECH CO LTD
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Problems solved by technology

At the same time, when the Ni content exceeds 60%, the positive electrode is in the delithiated state of Ni 4+ The content will also increase, and Ni4 + It is also very unstable and highly oxidizing, which can easily cause side reactions between the electrode and the electrolyte, which will sharply reduce the cycle performance and thermal stability of the material, thus affecting the practical use of materials with high nickel content.
[0003] At the same time, materials with high nickel content (>60%) are prone to excessive residual alkali content on the surface during sintering, because during the cooling stage, materials with high nickel content (>60%) will interact with moisture in the air And carbon dioxide, and then generate lithium hydroxide, lithium carbonate and other impurities, which will cause the residual alkali content of the sintered material to be too high
In the process of battery production, the residual alkali on the surface will decompose to varying degrees during the charging and discharging process, thereby producing CO 2 and other gases, making the material prone to flatulence during actual use, causing changes in the thickness of the battery and affecting the actual use of the material
If under the environmental conditions such as overcharging, the residual alkali on the surface can easily cause rapid side reactions and generate a large amount of gas and heat, resulting in thermal runaway of the battery, eventually leading to combustion and explosion of the battery, etc.
In order to reduce the amount of residual alkali on the surface of materials with high nickel content (>60%), the amount of lithium added during the sintering process can be reduced, but this often loses the electrical properties of the obtained materials, that is, cycle stability and discharge are often not obtained. The material with the best specific capacity

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  • A double-layer coating modified ternary positive high-nickel material and preparation method thereof
  • A double-layer coating modified ternary positive high-nickel material and preparation method thereof
  • A double-layer coating modified ternary positive high-nickel material and preparation method thereof

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preparation example Construction

[0032] The present invention also provides the preparation method of the above-mentioned double-coated modified ternary positive high-nickel material, which includes the following three steps:

[0033] Step 1, the precursor nickel-cobalt-manganese hydroxide is mixed with manganese salt to prepare a precursor coated with manganese salt;

[0034] Step 2, mixing the product of step 1 with a lithium salt, and sintering to obtain a ternary positive high-nickel material coated with manganese oxide;

[0035] In step 3, the product obtained in step 2 is mixed with a metal oxide and sintered to obtain a double-layer coated ternary positive high-nickel material.

[0036] Above-mentioned preparation method comprises the following steps:

[0037] Step 1, first dissolving the manganese salt evenly in the solvent I, then adding the precursor nickel cobalt manganese hydroxide, stirring, heating, removing the solvent I, and obtaining the precursor of the ternary positive electrode material c...

Embodiment 1

[0077] First, ultrasonically dissolve 20g of manganese acetate in 400g of ethanol solvent, and then slowly add the high-nickel ternary cathode material precursor Ni 0.65 co 0.20 mn 0.15 (OH) 2 1000g, after stirring at 500rpm for 30min, heat at 70°C until the solvent is completely evaporated to obtain a manganese acetate-coated precursor;

[0078] Then the obtained manganese acetate-coated precursor was pulverized, passed through a 300-mesh sieve, and then weighed 800g, and then weighed out 332g of required lithium carbonate according to the lithium ratio of 1.05. After mixing evenly by ball milling, sinter at 870°C for 15 hours in a muffle furnace with 45% oxygen, and after natural cooling, a ternary positive high-nickel material coated with manganese oxide is obtained;

[0079] Pass the obtained manganese oxide-coated ternary positive high-nickel material through a 300-mesh sieve, then weigh out 700g, then accurately weigh 1.4g of nano-alumina and mix it with it, and use a...

Embodiment 2

[0081] Dissolve 25g of manganese acetate in 400g of water solvent evenly by ultrasonic, and then slowly add Ni 0.70 co 0.20 mn 0.10 (OH) 2 1000g, after stirring at 500rpm for 30min, heat at 70°C until the solvent is completely evaporated to obtain a manganese acetate-coated precursor;

[0082] Then the obtained manganese acetate-coated precursor was pulverized, passed through a 300-mesh sieve, and then 800 g of the obtained manganese acetate-coated precursor was weighed, and then 332 g of required lithium carbonate was weighed out according to the lithium proportion of 1.05. After mixing evenly by ball milling, sintering at 840°C for 15 hours in a muffle furnace with 45% oxygen, and after natural cooling, a ternary positive high-nickel material coated with manganese oxide is obtained;

[0083] Pass the obtained manganese oxide-coated ternary positive high-nickel material through a 300-mesh sieve, and then weigh out 700g. Accurately weigh 1.4g of nano-titanium oxide additiv...

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Abstract

The invention provides a double-layer coating modified ternary positive high-nickel material and a preparation method thereof. The double-layer coating modified ternary positive high-nickel material has a double-layer coating structure, which is made of nickel-cobalt It consists of a lithium manganese oxide matrix, a manganese oxide coating layer and a metal oxide outer coating layer. The preparation method uses the precursor Ni of the ternary cathode material x co y mn 1‑x‑y (OH) 2 It is a precursor obtained by coating manganese oxide and metal oxide. The invention not only effectively reduces the residual alkali on the surface of the material, but also stabilizes the Ni generated when the material is fully charged. 4+ , improving its high-temperature storage performance and increasing its safety performance; at the same time, coating nano-metal oxide on the outer layer can effectively prevent the side reaction between the electrolyte and the material, improve the cycle performance of the material, increase the capacity retention rate of the material, and reduce the cost etc.

Description

technical field [0001] The invention relates to the field of positive electrode materials for batteries, in particular to a high-nickel positive electrode material in a lithium ion battery and a preparation method thereof. Background technique [0002] Since the commercial application of lithium-ion secondary batteries for the first time, it has rapidly become the current electronic consumer products such as mobile phones, computers, The main provider of electrical energy required by devices such as cameras. In recent years, with the vigorous development of electric vehicles and other industries, the current commercial lithium-ion battery cathode materials can no longer meet the requirements of high-power batteries, and high-capacity cathode materials have become a current research hotspot. Among them, nickel-cobalt-manganese ternary cathode material LiMO 2 (M=Ni, Co, Mn) has become the most promising cathode material for lithium-ion secondary batteries due to its higher t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/48H01M4/505H01M4/525
CPCY02E60/10
Inventor 王辉周宏宝吴朋朋沙金周玉林苏迎春
Owner TIANJIN GUOAN MGL NEW MATERIALS TECH CO LTD
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