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Preparation method of carbon/carbon nanotube coated lithium iron phosphate composite material by in situ synthesis

A technology for coating lithium iron phosphate and carbon nanotubes, which is applied to structural parts, electrical components, battery electrodes, etc., can solve the problems of complex preparation process and high cost, and achieve simple preparation process, good consistency, high carbon package coverage effect

Active Publication Date: 2017-06-20
合肥国轩科宏新能源科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Aiming at the deficiencies of the prior art, the present invention provides a preparation method for in-situ synthesis of carbon / carbon nanotube-coated lithium iron phosphate composite material, which solves the preparation process of carbon / carbon nanotube-coated lithium iron phosphate composite material in the prior art Complex and costly technical issues

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  • Preparation method of carbon/carbon nanotube coated lithium iron phosphate composite material by in situ synthesis
  • Preparation method of carbon/carbon nanotube coated lithium iron phosphate composite material by in situ synthesis

Examples

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preparation example Construction

[0031] (1) Preparation of the positive electrode sheet of the battery: The synthesized carbon / carbon nanotube-coated lithium iron phosphate composite material and the binder polyvinylidene fluoride (PVDF) were weighed at a mass ratio of 8:2. Mix the binder and the organic solvent N-methylpyrrolidone (NMP) and dissolve it, add carbon / carbon nanotube-coated lithium iron phosphate composite material and stir well to form a slurry, coat it on the surface of carbon-coated aluminum foil, and roll it after drying Press to get the battery positive plate.

[0032] (2) Battery assembly and performance testing: CR2016 button cells were used to test the electrochemical performance of carbon / carbon nanotube-coated lithium iron phosphate composites. The positive electrode sheet after rolling was punched into a positive electrode sheet with a diameter of 12 mm, and after accurate weighing, the effective mass of the carbon / carbon nanotube-coated lithium iron phosphate composite material was c...

Embodiment 1

[0035] In-situ synthesis of carbon / carbon nanotube-coated lithium iron phosphate composite material in this embodiment comprises the following steps:

[0036] S1. Weigh 10 parts of 500-mesh iron powder and add it to 40 parts of phosphate for mixing, control the pH of the solution to 2.0 and perform high-speed ball milling for 3 hours, add the oxidant hydrogen peroxide drop by drop and continue to stir and mix evenly until the dark green Fe(H 2 PO 4 ) 3 The color of the solution gradually recedes and stops adding hydrogen peroxide to form an insoluble ferric phosphate dihydrate.

[0037] S2. Add 200 parts of water, 6 parts of lithium carbonate, 0.5 part of glucose, 0.5 part of polyvinyl alcohol and 0.5 part of melamine to the above insoluble phosphoric acid dihydrate, mix and stir for 3 hours, then ball mill for 3 hours, control the speed at 500rpm, after the ball milling is completed Obtain milky yellow viscous slurry;

[0038] S3. Use a centrifugal spray drying tower to dr...

Embodiment 2

[0043] The preparation method of the present embodiment is the same as that of Example 1, the difference is only: the carbon source used is 0.6 part of glucose, 0.3 part of polyvinyl alcohol, and 0.6 part of melamine when synthesizing the carbon / carbon nanotube-coated lithium iron phosphate composite material; The constant temperature of the nitrogen atmosphere is 400°C, the constant temperature of the nitrogen-hydrogen mixed gas atmosphere is 900°C, and the content of amorphous carbon and carbon nanotubes is controlled to obtain a carbon / carbon nanotube-coated lithium iron phosphate composite material.

[0044] According to the same test method as in Example 1, the specific surface area analysis and electrical performance analysis of the in-situ synthesized carbon / carbon nanotube-coated lithium iron phosphate composite material obtained in this example were carried out. The carbon / carbon nanotube-coated iron phosphate prepared in this example The specific surface area of ​​the...

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Abstract

The invention provides a preparation method of a carbon / carbon nanotube coated lithium iron phosphate composite material by in situ synthesis, and relates to the technical field of battery materials. The preparation method provided by the invention comprises the steps of weighing raw materials of a lithium source, iron powder, a phosphate and a carbon source; first performing ball-milling on the iron powder and the phosphate and adding hydrogen peroxide; and then adding the lithium source and the carbon source to obtain a slurry, drying and sintering under the protection of reducing / inert gas to obtain the composite material. According to the preparation method provided by the invention, the carbon / carbon nanotube coated lithium iron phosphate composite material is prepared by employing an in-situ synthesis method, so the heat treatment time is short; the composite material has relatively high carbon coating rate, stable electrochemical property and relatively good consistency, the cycle performance and the rate performance are greatly improved, the whole preparation process is simple, and the preparation method has the advantages of safety, high efficiency, low cost and environmental protection, etc.

Description

technical field [0001] The invention relates to the technical field of battery materials, and relates to a preparation method for in-situ synthesis of carbon / carbon nanotube-coated lithium iron phosphate composite materials. Background technique [0002] Lithium iron phosphate has many advantages such as environmental friendliness, high safety, and long cycle life, and has become the most widely used cathode material in the industrialization of lithium-ion power batteries. However, the low electronic conductivity and lithium ion diffusion rate of lithium iron phosphate lead to poor rate performance, which seriously restricts the market promotion and application ability of lithium iron phosphate power battery. At present, lithium iron phosphate is mainly modified from the following three aspects. (1) Lithium iron phosphate is mixed with conductive materials or coated with conductive materials to increase the conductivity of the material; (2) Prepare nanoscale high-density sp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/587H01M4/36
CPCH01M4/366H01M4/5825H01M4/587Y02E60/10
Inventor 秦家成
Owner 合肥国轩科宏新能源科技有限公司
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