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A kind of manganese-based composite cathode material and preparation method thereof

A composite positive electrode material, manganese-based technology, applied in the direction of battery electrodes, structural parts, electrical components, etc., can solve the problems of poor performance of lithium-ion batteries, shortened battery life, poor battery life, etc., to reduce side reactions and attenuation probability, stress relief, and low-cost effects

Active Publication Date: 2019-06-04
广西平果润民发展有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In the early stage of research on cathode materials for lithium-ion batteries, there were mainly several systems such as lithium cobalt oxide, lithium nickel oxide, and lithium manganese oxide. It is the main positive electrode material used in today's commercial lithium-ion batteries, but cobalt is expensive and poor in safety, especially in large-scale and power-type batteries. It is mainly used in small electronic devices, and it is difficult to store energy in electric vehicles. Promotion of large application fields; lithium nickel oxide (LiNiO2) has a layered structure similar to lithium cobalt oxide, high specific energy, good cycle performance, and moderate price, but the conditions for preparing lithium nickel oxide are extremely harsh and are not widely used; lithium manganese Oxygen materials have the advantages of rich raw materials, low cost, and no environmental pollution, but their dissolution at higher temperatures causes capacity loss, low cycle life, and low specific capacity. Although in the prior art, some researchers have targeted this type of product Doping with Ni, Co, Cr and other elements to improve the Li / Mn ratio can achieve the purpose of improving the above defects, but the specific capacity of the prepared lithium manganese oxide material is still about 120-130mAh / g, making the lithium ion battery poor performance
Moreover, the cost of doping materials with elements such as Ni and Co increases more
[0006] For this reason, other technical means have appeared in the prior art, such as phosphate LiMPO 4 (M=Fe, Co, Ni, Mn, V, etc.), Li 3 V 2 (PO 4 ) 3 , Silicate Li 2 MSiO 4 (M=Fe, Mn) and titanate Li 2 MTiO 4 (M=Ni, Fe, Mn), but the specific capacity of the material in the above-mentioned prior art is still low, and then the specific energy of the battery that causes preparation is still low, even some materials also can cause electrolysis because of the high potential. The liquid decomposes, which shortens the service life of the battery
[0007] The reason for the above phenomenon is that whether it is layered LiMO 2 (including LiCoO 2 、LiNi 1 / 3 co 1 / 3 mn 1 / 3 o 2 and its congeners), or spinel-type LiMn 2 o 4 , or olivine-type LiMPO 4 etc., each molecule of which contains only one variable 1-valent transition element atom, so that the lithium ion that can be removed during charging is at most one, LiMO with the smallest molecular weight 2 , its theoretical specific capacity is about 274mAh / g, so that when it ensures the stability of the crystal structure, only 0.5-0.65 lithium ions can be removed, so that its actual specific capacity is about 140mAh / g, resulting in the following The specific energy of the battery prepared by it as the positive electrode material of the battery is low; and, the solid solution material of layered and spinel or the olivine type material, etc., when it has the trivalent, tetravalent and M valence of lithium-rich manganese, It can make its specific capacity higher, but after this kind of material is prepared into a battery, due to the high voltage of the lithium-rich manganese material, it is easy to cause the electrolyte to decompose, and the specific capacity decays quickly, making the service life of the prepared battery poor.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] At room temperature, use 500 g of 95% ethanol to dissolve 1.7 g of phenolic resin into a solution; then add 5 g of spinel lithium manganate whose particle size is concentrated at 0.3-10 microns, stir to form a suspension, and then add manganese acetate, Add lithium hydroxide, chromium nitrate, and lanthanum nitrate, and control the atomic ratio of lithium, lanthanum, chromium, and manganese to 1.91:0.03:0.03:0.97. Stir for 30 minutes, dissolve lithium hydroxide with 350g of water, add, stir at constant temperature to form a suspension;

[0036] Heat the above suspension to 80°C for treatment, so that the phenolic resin will evenly bond and coat the deposit on the surface of the spinel lithium manganate particles. The treatment time is until the solvent is completely evaporated to obtain the precursor;

[0037] Put the above-mentioned precursor in a microwave kiln, heat treatment with nitrogen as a protective gas, the linear flow rate of nitrogen in the microwave kiln is...

Embodiment 2

[0040] At room temperature, use 300 g of 95% ethanol to dissolve 0.85 g of phenolic resin into a solution; then add 5 g of spinel lithium manganate whose particle size is concentrated at 0.3-10 microns, stir to form a suspension, and then add manganese acetate, Add lithium hydroxide, chromium nitrate, and lanthanum nitrate, and control the atomic ratio of lithium, lanthanum, chromium, and manganese to 1.91:0.03:0.03:0.97. Stir for 30 minutes, dissolve lithium hydroxide with 125g of water, add, stir at constant temperature to form a suspension;

[0041] Heat the above suspension to 60°C for treatment, so that the phenolic resin will evenly bond and coat the deposit on the surface of the spinel lithium manganate particles. The treatment time is until the solvent is completely evaporated to obtain the precursor;

[0042] Put the above-mentioned precursor in a horse boiling furnace, heat treatment with nitrogen as a protective gas, the linear flow rate of nitrogen in the horse boi...

Embodiment 3

[0045] At room temperature, 500 g of 95% ethanol was used to dissolve 0.85 g of phenolic resin into a solution; then 5 g of spinel lithium manganate with a particle size of 0.3-10 microns was added, stirred to form a suspension, and manganese acetate, Add lithium hydroxide, chromium nitrate, and lanthanum nitrate, and control the atomic ratio of lithium, lanthanum, chromium, and manganese to 1.55:0.15:0.15:0.85. Stir for 30 minutes, dissolve lithium hydroxide with 250g of water, add, stir at constant temperature to form a suspension;

[0046] Heat the above suspension to 80°C for treatment, so that the phenolic resin will evenly bond and coat the deposit on the surface of the spinel lithium manganate particles. The treatment time is until the solvent is completely evaporated to obtain the precursor;

[0047] Put the above-mentioned precursor in a microwave oven, heat treatment with nitrogen as a protective gas, the linear flow velocity of nitrogen in the microwave oven is not ...

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Abstract

The invention relates to the manufacturing technical field of a battery material, and particularly to a manganese-based composite positive electrode material and a preparation method therefor. Through the matching of a manganese source, a lithium source, a chromium source, a lanthanum source, a binder, a solvent and spinel lithium manganate particles, the spinel lithium manganate particles can be taken as the core; a high-valance lithium-rich phase can be formed in the middle layer and a low-valence Li<2>MnO<2> phase can be formed in the outer layer; consequently, the spinel lithium manganate energy storage part is formed in the interior; the high-valance lithium-rich phase energy storage part is formed in the middle; the Li<2>MnO<2> phase energy storage part is formed in the outer layer; the specific capacity of the positive electrode material is effectively improved; the outer layer of the spinel lithium manganate particles is coated with the low-valance-state material, so that the dissolution of the spinel lithium manganate and the attenuation of the high-valence lithium-rich phase in the middle layer are effectively restrained; and the outer layer is coated with the phase with much lithium, so that the rate of decay of the positive electrode is effectively lowered and the specific capacity of the positive electrode material is improved.

Description

technical field [0001] The invention relates to the technical field of battery material production, in particular to a manganese-based composite positive electrode material and a preparation method thereof. The invention belongs to the field of electrochemical engineering and industrial devices, and it can be used as an electrode active material in a lithium ion battery system of an aqueous solution and an organic electrolyte or a lithium battery system of an organic electrolyte. Background technique [0002] Since human society entered into industrialization, there has been a huge demand for coal and oil and other mineral energy. With the huge consumption of non-renewable energy such as coal and oil, resources are increasingly scarce. The greenhouse effect intensified by carbon dioxide emissions and the increasingly serious pollution of the air and ecological environment have posed a serious threat to the earth on which we live. Vigorously developing renewable energy such ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/505H01M4/131H01M4/1391H01M10/0525
CPCH01M4/131H01M4/1391H01M4/366H01M4/505H01M10/0525Y02E60/10
Inventor 高羽程杰朱寅中高申元
Owner 广西平果润民发展有限公司
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