Preparation method for lithium ferrous phosphate anode material coated by directly reduced nanocarbon

A technology of lithium iron phosphate and positive electrode materials, applied in nanotechnology, nanotechnology, chemical instruments and methods, etc., can solve the problems of difficult control of nanotube growth efficiency, uneven distribution of carbon nanotubes, unstable electrochemical performance, etc. , to achieve the effects of increased discharge voltage platform, simple preparation process, and good cycle performance

Active Publication Date: 2013-01-02
贵州唯特高新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the uneven distribution of carbon transported in the gas phase on the sample, the growth efficiency of nanotubes grown from carbon sources is difficult to control, and the grown nanotubes may not be in good contact with the lithium iron phosphate composite material, resulting in poor electrochemical performance of the prepared samples. Instability, and in the preparation of the sample, the carbon nanotubes will be unevenly distributed on the lithium iron phosphate, and there are shortcomings such as unstable batch performance of the prepared sample

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] 1) Preparation of carbon nanotubes by direct reduction

[0027] According to Na 2 SO 3 Weigh Na with a weight ratio of 1:1 to carbon nanotubes 2 SO 3 ; 2 SO 3 Mix with distilled water 200 times its volume to make Na 2 SO 3 solution, adding carbon nanotubes to Na 2 SO 3 In the solution, heat treatment at 30° C. for 1 h in an ultrasonic oscillator; after suction filtration and washing, dry at room temperature for 3 h under a pressure of 10 Pa to prepare direct reduced carbon nanotubes.

[0028] 2) Weigh lithium dihydrogen phosphate and ferrous oxalate according to the molar ratio of lithium ion: ferrous ion: phosphate ion: 0.95: 0.90: 0.95; weigh 3.62% of the theoretical output of lithium ferrous phosphate based on the weight of the reaction compound direct reduction of carbon nanotubes. Measure distilled water according to 0.8 times the volume of the total volume of lithium dihydrogen phosphate and ferrous oxalate.

[0029] Mix the weighed lithium dihydrogen p...

Embodiment 2

[0031] 1) Preparation of direct reduction graphene

[0032] Weigh sodium borohydride at 1: 1000 according to the weight ratio of sodium borohydride and graphene; Sodium borohydride is mixed with deionized water of 200 times its volume to prepare sodium borohydride solution, and graphene is added to sodium borohydride solution heat treatment at 90°C for 1 h in an ultrasonic oscillator; after suction filtration and washing, dry at room temperature for 3 h at a pressure of 10132 Pa to obtain directly reduced graphene.

[0033] 2) Weigh the reaction compounds lithium dihydrogen phosphate and ferrous oxalate according to the molar ratio of lithium ion: ferrous ion: phosphate ion 1.10: 1.05: 1.10. 14.5% by weight of the theoretical yield of lithium iron phosphate calculated on the basis of the weight of the reaction compound weighs directly reduced graphene. Measure ethanol according to 20 times the total volume of lithium dihydrogen phosphate and ferrous oxalate.

[0034] Mix wei...

Embodiment 3

[0036] 1) Preparation of graphene oxide by direct reduction

[0037] Weigh hydrazine hydrate at 1:100 according to the weight ratio of hydrazine hydrate and graphene oxide; hydrazine hydrate is mixed with distilled water 200 times its volume to obtain a hydrazine hydrate solution, and graphene oxide is added to the hydrazine hydrate solution. Heat treatment at 50°C for 1 h in a shaker; filter and wash with suction and dry at room temperature at 100 Pa for 3 h to prepare directly reduced graphene oxide.

[0038] 2) according to lithium ion: ferrous ion: the molar ratio of phosphate ion is 1.00: 1.00: 1.00 weighing reaction compound lithium acetate, ferrous oxalate, phosphoric acid; 8.1% of the theoretical yield of ferrous phosphate based on the weight of reaction compound calculation % wt. direct reduced graphene oxide. Measure formaldehyde based on 10 times the total volume of lithium acetate, ferrous oxalate, and phosphoric acid.

[0039] Mix the weighed lithium acetate, fe...

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PUM

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Abstract

The invention relates to a preparation method for a lithium ferrous phosphate anode material coated by directly reduced nanocarbon, which comprises the steps: mixing a reducer and water; then adding nanocarbon into the mixture of the reducer and water; obtaining the directly reduced nanocarbon by heating, ultrasonication, filtering and drying and the like; mixing the directly reduced nanocarbon with a lithium source compound, a ferrous source compound, a phosphorus source compound and a wet grinding medium, and vacuum drying to obtain dry powder; placing the dry powder in an inertial atmosphere or a reducing atmosphere, and preparing the lithium ferrous phosphate anode material coated by directly reduced nanocarbon by a two sectional sintering method. The electrode material prepared by the invention is uniform in component and excellent in discharge performance, and in particular optimal circulating performance under large current.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery electrode materials, and relates to a method for preparing a direct-reduction nano-carbon-coated lithium iron phosphate cathode material that can be used for lithium-ion batteries, lithium batteries, polymer lithium-ion batteries and supercapacitors. technical background [0002] As a new generation of energy systems, lithium-ion batteries are widely used in electric vehicles, satellites, aerospace and military fields. Numerous studies have shown that LiFeP0 4 May become one of the most promising cathode materials for lithium-ion batteries. However, since LiFeP0 4 Due to the limitations of its own structure, the material has low electronic conductivity and poor ion conductivity, resulting in poor performance of high-rate charge and discharge, and it cannot meet the requirements of practical applications without modification. In order to overcome the shortage of lithium iron phosphat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58C01B25/45B82Y30/00
CPCY02E60/12Y02E60/10
Inventor 童庆松
Owner 贵州唯特高新能源科技有限公司
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