Nanosheet piled lithium iron phosphate/graphene composite material and preparation method thereof

A graphene composite and lithium iron phosphate technology, applied in electrical components, electrochemical generators, battery electrodes, etc., can solve problems such as low electronic conductivity, slow lithium ion migration rate, and limit wide application, so as to improve conductivity , reduce the specific surface area, reduce the effect of the diffusion path

Active Publication Date: 2017-02-15
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the low intrinsic electronic conductivity and slow lithium ion migration rate of lithium iron phosphate severely limit its wide application in lithium ion batteries.

Method used

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  • Nanosheet piled lithium iron phosphate/graphene composite material and preparation method thereof
  • Nanosheet piled lithium iron phosphate/graphene composite material and preparation method thereof
  • Nanosheet piled lithium iron phosphate/graphene composite material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] In the lithium iron phosphate / graphene composite material stacked by nanosheets in this embodiment, the nanosheet-shaped lithium iron phosphate is stacked in situ to form a micron-sized shuttle-shaped particle, and is composited with graphene to form a positive electrode material; the thickness of the lithium iron phosphate nanosheet It is 50-55nm; the size of micron-sized shuttle particles is 4.0-5.5μm.

[0029] The preparation method comprises the following steps:

[0030] (1) Dissolve 0.03mol of lithium hydroxide and 0.01mol of ferrous sulfate heptahydrate in 40ml of ethylene glycol to prepare lithium hydroxide solution with a concentration of 0.75M and ferrous sulfate solution with a concentration of 0.25M;

[0031] (2) Add 0.01 mol of phosphoric acid and the solution containing lithium source obtained in step (1) dropwise into the solution containing iron source obtained in step (1), and add 0.5 g of ammonium persulfate and 1.6 g of graphene oxide respectively to f...

Embodiment 2

[0038] In the lithium iron phosphate / graphene composite material stacked by nanosheets in this embodiment, the nanosheet-shaped lithium iron phosphate is stacked in situ to form a micron-sized shuttle-shaped particle, and is composited with graphene to form a positive electrode material; the thickness of the lithium iron phosphate nanosheet It is 45-50nm; the size of micron-sized shuttle particles is 3.5-4.5μm.

[0039] The preparation method comprises the following steps:

[0040] (1) Dissolve 0.03mol of lithium hydroxide and 0.01mol of ferrous sulfate heptahydrate in 40ml of ethylene glycol to prepare lithium hydroxide solution with a concentration of 0.75M and ferrous sulfate solution with a concentration of 0.25M;

[0041] (2) Add 0.015 mol of phosphoric acid and the solution containing the lithium source obtained in step (1) dropwise into the solution containing the iron source obtained in step (1), and add 0.5 g of ammonium persulfate and 0.8 g of graphene oxide respecti...

Embodiment 3

[0047] In the lithium iron phosphate / graphene composite material stacked by nanosheets in this embodiment, the nanosheet-shaped lithium iron phosphate is stacked in situ to form a micron-sized shuttle-shaped particle, and is composited with graphene to form a positive electrode material; the thickness of the lithium iron phosphate nanosheet It is 55-60nm; the size of micron-sized shuttle particles is 4.0-5.0μm.

[0048] The preparation method comprises the following steps:

[0049] (1) Dissolve 0.027mol of lithium hydroxide and 0.01mol of ferrous sulfate heptahydrate in 40ml of ethylene glycol to prepare lithium hydroxide solution with a concentration of 0.338M and ferrous sulfate solution with a concentration of 0.125M;

[0050] (2) Add 0.01 mol of phosphoric acid and the solution containing lithium source obtained in step (1) dropwise into the solution containing iron source obtained in step (1), and add 0.5 g of ammonium persulfate and 1.6 g of graphene oxide respectively t...

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Abstract

The invention discloses a nanosheet piled lithium iron phosphate / graphene composite material and a preparation method thereof. The composite material is an anode material formed by compounding micron-level shuttle type particles formed by piling up nanosheet type lithium iron phosphate in situ with graphene. The preparation method comprises the following steps: 1, respectively dissolving a lithium source and an iron source in ethylene glycol; 2, dripping phosphoric acid and the lithium source-containing solution into the iron source-containing solution in sequence, and respectively adding ammonium persulfate and graphene oxide to form dispersion liquid; 3, transferring the dispersion liquid into a stainless steel reaction kettle with a polytetrafluoroethylene inner container, reacting at certain temperature for a period of time, naturally cooling to room temperature, respectively washing obtained precipitates with deionized water and absolute ethyl alcohol, performing centrifugal separation, and placing into a drying box for drying; 4, roasting an obtained precipitate sample under protection atmosphere, and performing furnace cooling to room temperature to obtain the nanosheet piled lithium iron phosphate / graphene composite material. The preparation method disclosed by the invention is simple in technological flow and low in cost, and the obtained anode material is excellent in electrochemical property.

Description

technical field [0001] The invention relates to a lithium ion battery positive electrode material and a preparation method thereof, in particular to a nano-sheet stacked lithium iron phosphate / graphene composite positive electrode material and a preparation method thereof. Background technique [0002] Lithium-ion battery is the latest chemical power source. It is composed of two compounds that can reversibly intercalate and extract lithium ions as positive and negative electrodes. It has high energy density, high power density, environmental friendliness, long service life and superior safety performance. And other advantages, has become an ideal energy storage device. [0003] Among many cathode materials for lithium-ion batteries, lithium iron phosphate is currently one of the most promising cathode materials for lithium-ion power batteries due to its high theoretical capacity (170 mAh / g), good stability, and low cost. However, the low intrinsic electronic conductivity a...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M10/0525
CPCH01M4/362H01M4/5825H01M4/625H01M10/0525Y02E60/10
Inventor 喻万景安长胜张宝易旭郑俊超童汇张佳峰何文洁
Owner CENT SOUTH UNIV
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