Method for modifying nanometer LiMnPO4/C cathode material coated with lithium ion conductor

A positive electrode material, lithium ion technology, applied in the field of lithium ion battery positive electrode material preparation, can solve problems such as difficult to control uniformity, complex process, etc., and achieve the effect of easy control of reaction conditions, simple process, and uniform coating layer

Active Publication Date: 2016-03-23
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a high-efficiency modification method for surface coating of lithium ion positive electrode materials, which solves the pro

Method used

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  • Method for modifying nanometer LiMnPO4/C cathode material coated with lithium ion conductor
  • Method for modifying nanometer LiMnPO4/C cathode material coated with lithium ion conductor
  • Method for modifying nanometer LiMnPO4/C cathode material coated with lithium ion conductor

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Experimental program
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Effect test

Embodiment 1

[0034] 0.3molLiOH·H 2 OEG-H 2 O solution was added dropwise to 0.1mol H 3 PO 4 solution, a milky white suspension was obtained, and then 0.1molMnSO was added 4 solution and 10g of glucose, mixed evenly, sealed, and solvothermally reacted at 180°C for 12 hours to obtain the hydroxylated LiMnPO on the surface 4 / C material, wherein control EG in the reactor is 950ml, H 2 O is 50ml. Weigh 5 g of surface hydroxylated LiMnPO 4 / C material, dispersed in 50ml of isopropanol, stirred evenly to obtain a dispersion; then, measure 1.75ml of titanate coupling agent TC-201 and dissolve it in 8ml of isopropanol, stir to form a solution, and stir Add it to the above dispersion under the condition of , then add 5ml of isopropanol to the mixture and stir for 2 hours, then dry it at 60°C; finally mix the dried mixture with 0.068g of lithium carbonate and 1.2g of polyethylene glycol, Under a nitrogen protective atmosphere, calcined at 700 ° C for 2 hours to obtain a lithium ion conductor ...

Embodiment 2

[0037] Take by weighing 3g the surface hydroxylated LiMnPO obtained according to the aforementioned method (embodiment 1) 4 / C material, dispersed in 30mL of absolute ethanol, stirred evenly to obtain a dispersion; then, measure 0.4ml of vanadyl triisopropoxy, added to 6ml of absolute ethanol, stirred evenly to form a solution, and stirred Then, slowly add 6ml of deionized water into the mixture, continue to stir for 2 hours, and then dry it at 85°C; finally mix the dried mixture with 0.6g amylopectin. Under the mixed protective atmosphere of argon-hydrogen (95:5), bake at 650°C for 2 hours to obtain 5% V 2 o 5 Surface-coated LiMnPO 4 / C cathode material.

Embodiment 3

[0039] 0.09molLiOH·H 2 OEG-H 2 O solution was added dropwise to 0.06mol LiH 2 PO 4 solution, a milky white suspension was obtained, and then 0.06molMnAc was added 2 solution and 6g of glucose, mixed evenly, sealed, and solvothermally reacted at 200 °C for 4 hours to obtain LiMnPO rich in hydroxyl groups on the surface 4 / C material, wherein control EG in the reactor is 540ml, H 2 O is 60ml. Weigh 8 g of the surface hydroxylated LiMnPO 4 / C material, dispersed in 20mL of deionized water, stirred evenly, to obtain a dispersion; then, weighed 0.08g of vanadium pentoxide, dissolved in 4ml of deionized water containing hydrogen peroxide, stirred to form a sol, under stirring conditions Add to the above dispersion liquid, then add 4ml deionized water to the mixed liquid and stir and mix for 1 hour; then dry at 80°C; finally mix the dried mixture with 1.8g polyvinyl alcohol, under argon protective atmosphere , baked at 600°C for 6 hours to obtain a coating of 1% V 2 o 5 The ...

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Abstract

The present invention provides a method for modifying a nanometer LiMnPO4/C cathode material coated with a lithium ion conductor, so as to solve the problem that an LiMnPO cathode material is low in rate performance and cycling performance. The method for modifying the nanometer LiMnPO4/C cathode material coated with the lithium ion conductor is characterized by comprising the following steps: (1) preparing an LiMnPO4/C cathode material with a hydroxylated surface by means of solvent thermal carbonization; (2) controlling formation of an oxide precursor coating layer, so as to complete assembly of an LiMnPO4/C@MOP (a metal oxide precursor) core-shell structure; and (3) using a one-step calcination method to prepare a lithium ion conductor modified composite cathode material LiMnPO4@Li2TiO3/C or LiMnPO4@V205/C. According to the method provided by the present invention, the process of the invention is simple, the prepared lithium ion conductor modified composite cathode material LiMnPO4/C is used in a lithium ion battery, so that cycling stability is good, a charge and discharge capacity is high, and rate performance is excellent.

Description

technical field [0001] The invention belongs to the technical field of preparation of positive electrode materials of lithium ion batteries, and relates to a preparation method for surface coating of positive electrode materials of lithium ion batteries. Background technique [0002] Recently, in the study of phosphate carbon coating, it was found that the structure of the surface carbon coating changes when the electrode is cycled at high rates, which will lead to a decrease in electrical conductivity. LiMnPO 4 The conductivity of the surface carbon layer will also decrease under the action of the electrolyte, and the LiMnPO 4 A higher charge cut-off voltage of 4.3V or higher is required, which will exacerbate the decline in the conductivity of the carbon layer during high-rate cycling. This requires optimizing the surface structure and electrical conductivity of the material. By introducing new functional phases into the surface coating layer to construct a uniformly dis...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/48H01M4/58H01M4/62H01M10/0525
CPCH01M4/366H01M4/483H01M4/5825H01M4/625H01M10/0525Y02E60/10
Inventor 胡国荣曹雁冰彭忠东杜柯张志坚李敏
Owner CENT SOUTH UNIV
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