Preparation method of coated lithium manganate

A technology of coating lithium manganese oxide and coating lithium manganate, which is applied in the field of materials, can solve the problems of high local current, uneven coating, and failure to reduce the contact between active material and electrolyte, and achieve good high-temperature cycle performance , Improve the stability and life of the effect

Inactive Publication Date: 2014-08-20
SHANGHAI ELECTRICGROUP CORP +1
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  • Abstract
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AI Technical Summary

Problems solved by technology

The first type of mechanical mixing and sintering method has a simple synthesis process. It only needs to mechanically mix the active material and the coating material, and then calcine the product at a low temperature. However, the thickness of the coating layer of the material prepared by this method is difficult to control, and the coating Inhomogeneous, the problem of excessive local current is prone to occur during the charging and discharging process of the battery, and the coating layer prepared by this method has poor bonding force with the surface of the active material, which does not play a role in reducing the contact between the active material and the electrolyte
The second type of molten salt method, the synthesis process of this method is simple, and the bonding force between the coating layer and the active material is also improved, but the available coating materials are very limited, and materials with high melting points such as oxides are not suitable for this method , and the thickness of the cladding layer prepared by this method is not uniform

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  • Preparation method of coated lithium manganate
  • Preparation method of coated lithium manganate
  • Preparation method of coated lithium manganate

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[0029] A method for preparing coated lithium manganate according to an embodiment of the present invention, comprising: preparing a metal oxide; adding lithium manganate to water, stirring and dispersing to form a suspension, and adjusting the pH of the suspension to 6-8; Add the prepared metal oxide into the suspension, stir for 0.8 to 1.5 hours to make it adsorb on lithium manganate LiMn 2 o 4 Surface: the product in step 3 is centrifugally washed and dried, and calcined to obtain metal oxide-coated lithium manganate.

[0030] The metal oxides used in the embodiments of the present invention are titanium dioxide, silicon dioxide, aluminum oxide, lanthanum oxide, or iron oxide. Titanium dioxide is preferred, including anatase titanium dioxide or rutile titanium dioxide of type A or type B.

[0031] Lithium manganate LiMn 2 o 4 Preferred is spinel lithium manganese oxide LiMn 2 o 4 , can also be doped with one or more other metal elements to form a doped compound LiMxMn2...

Embodiment 1

[0034] First, prepare a mixed solution of hydrogen peroxide and ammonia with a volume ratio of 2:1, add 200-300 mesh titanium powder to the above aqueous solution, and stir for one hour. Glycolic acid was then added to the solution, and stirred at 80° C. for two hours. Next, the above solution was transferred to a hydrothermal kettle and reacted at 160° C. for two hours. The prepared B-type titanium dioxide is centrifugally washed and dried for use.

[0035] The LiMn prepared by the traditional solid-phase method 2 o 4 Add to a certain amount of water, stir to disperse, and adjust the pH value of the solution to 6-8 with dilute sulfuric acid.

[0036] A certain amount of B-type titanium dioxide was added to the above suspension, and stirred for one hour. The prepared product was centrifugally washed and dried, and finally calcined at a low temperature (≤500°C) to prepare B-type titanium dioxide-coated spinel-type lithium manganate LiMn 2 o 4 .

Embodiment 2

[0038] First, prepare 50ml of 1mmol / L aluminum acetate aqueous solution, slowly drop 0.5-2mL of ammonia water into the solution, stir for one hour, then centrifugally wash and dry. Next, the solid powder is calcined in the air and kept at 160° C. for one hour.

[0039] LiMn prepared by traditional solid-phase method 2 o 4 Add to a certain amount of water, stir to disperse, and adjust the pH value of the solution to 6-8 with dilute sulfuric acid.

[0040] Add a certain amount of Al2O3 powder into the above suspension and stir for one hour. The prepared product is centrifugally washed and dried, and finally calcined at a low temperature (≤500°C) to prepare alumina-coated spinel-type lithium manganate LiMn 2 o 4 .

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Abstract

The invention provides a preparation method of coated lithium manganate. The method includes the steps of: preparing a metal oxide; adding lithium manganate to water, stirring to disperse and form a suspension, and adjusting the pH value of the suspension to 6-8; adding the prepared metal oxide into the suspension, stirring for 0.8-1.5 h; and centrifuging, washing and drying the products obtained in the step 3, and calcining to obtain the metal oxide coated lithium manganate. The technical scheme provided by the invention can synthesize a lithium manganese oxide coated layer in nano scale and having uniform thickness in water system, and the coated lithium manganate has better high temperature cycle performance than the LiMn2O4 synthesized by a conventional method. When applied to lithium ion battery, the coated lithium manganate can improve the stability and service life of the battery.

Description

technical field [0001] The invention belongs to the technical field of materials, and relates to a metal oxide-coated lithium manganese oxide LiMn used as a positive electrode material of a lithium-ion battery 2 o 4 synthetic method. Background technique [0002] With the depletion of petroleum resources and the aggravation of environmental pollution, battery-powered hybrid electric vehicles and pure electric vehicles have become a global hot topic. Recently, countries around the world have given significant support to the development of electric vehicles and formulated corresponding development plans, hoping to alleviate the increasingly serious energy crisis and air pollution problems. At present, large lithium-ion batteries are considered to be the most potential automotive power batteries. Many automobile manufacturers at home and abroad are embarking on the research of lithium-ion batteries for vehicles, and have already achieved partial commercialization. Spinel-ty...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/505
CPCY02E60/122H01M4/366H01M4/505Y02E60/10
Inventor 廖文俊刘佳丽李佳姚一一丁柳柳强璐余爱水商业盛苏秀丽
Owner SHANGHAI ELECTRICGROUP CORP
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