Method for synthesizing carbon-coated lithium ferrous pyrophosphate by hydrothermal method

A carbon-coated technology for lithium iron pyrophosphate and lithium iron pyrophosphate, which is used in electrical components, electrochemical generators, battery electrodes, etc. good, irregular crystal form, etc., to achieve the effects of excellent electrochemical performance, fine powder, and short synthesis cycle.

Active Publication Date: 2014-08-13
CENT SOUTH UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is to overcome the disadvantages of the existing synthesis method, such as uneven particles of the positive electrode material lithium iron pyrophosphate, irregular crystal form, high reaction temperature, poor electrochemical performance, etc., to provide a low reaction temperature, The synthesis method is a simple hydrothermal method for synthesizing carbon-coated lithium iron pyrophosphate, and the prepared positive electrode material carbon-coated lithium iron pyrophosphate has excellent electrochemical performance

Method used

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  • Method for synthesizing carbon-coated lithium ferrous pyrophosphate by hydrothermal method
  • Method for synthesizing carbon-coated lithium ferrous pyrophosphate by hydrothermal method
  • Method for synthesizing carbon-coated lithium ferrous pyrophosphate by hydrothermal method

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Embodiment 1

[0035] This embodiment includes the following steps:

[0036] (1) This example is designed to generate 0.01mol of the target product Li 2 FeP 2 o 7 , prepare 100ml of the solution; weigh 0.01mol of citric acid, add it into a beaker with 40ml of deionized water, put the beaker into a 50°C constant temperature water bath, and stir magnetically; weigh 0.005mol of ferric sulfate (Fe 2 (SO 4 ) 3 ) and 0.04mol of lithium hydroxide, measure 0.02mol of orthophosphoric acid, add them to three small beakers with 20ml of deionized water respectively, stir until they are completely dissolved, add the solutions containing iron source and lithium source in turn into the solution with carbon source dissolved, then add ammonia water to adjust the pH of the mixed solution to 6, and then add the solution containing phosphorus source to the mixed solution, then the iron ion concentration in the iron source is 0.1 mol L -1 , magnetically stir the mixed solution in a water bath at 50°C for 1 ...

Embodiment 2

[0043] This embodiment includes the following steps:

[0044] (1) This example is designed to generate 0.1mol of the target product Li 2 FeP 2 o 7 , prepare solution 1000ml; Weigh 0.1mol ascorbic acid, add in the beaker that 400ml deionized water is arranged, put the beaker into 60 ℃ constant temperature water bath, stir evenly with a mixer; Weigh respectively 0.1mol ferric nitrate and 0.3mol Lithium carbonate, measure 0.2mol ammonium dihydrogen phosphate, add respectively in 3 small beakers that are equipped with 200ml deionized water, stir respectively until it all dissolves; In the solution with carbon source, then add ammonia water to adjust the pH of the mixed solution to 5, and then add the solution containing phosphorus source to the mixed solution, then the iron ion concentration in the iron source is 0.1 mol L -1 , magnetically stir the mixed solution in a water bath at 80°C for 1 h;

[0045] (2) Pour the mixed solution into an integrated temperature-controlled st...

Embodiment 3

[0049] This embodiment includes the following steps:

[0050] (1) This embodiment is designed to generate 0.05mol target product Li 2 FeP 2 o 7 , prepare solution 1000ml; Weigh 0.06mol polyethylene glycol, add in the beaker that 550ml deionized water is arranged, put the beaker in 60 ℃ of constant temperature water baths, stir evenly with agitator; Take by weighing 0.05mol respectively The lithium acetate of ferrous iron and 0.25mol, measure 0.11mol ammonium dihydrogen phosphate, add in 3 small beakers that 150ml deionized water is housed respectively, stir until it all dissolves respectively; Add the solution to the solution containing the carbon source in turn, then add ammonia water to adjust the pH of the mixed solution to 4, then add the solution containing the phosphorus source to the mixed solution, then the concentration of iron ions in the iron source is 0.05 mol L -1 , magnetically stir the mixed solution in a water bath at 80°C for 2 hours;

[0051] (2) Pour the...

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Abstract

The invention discloses a method for synthesizing carbon-coated lithium ferrous pyrophosphate by a hydrothermal method. The method comprises the following steps of (1) weighing raw materials, dissolving a carbon source into distilled water or deionized water, and heating, stirring and dissolving in a water bath at the temperature of 50-90 DEG C; respectively dissolving a lithium source, an iron source and a phosphorus source into the deionized water, uniformly stirring the sources, sequentially adding the iron source and the lithium source into a solution dissolved with the carbon source, adding ammonia water to adjust the pH of the mixed solution to 4-6, adding the phosphorus source, heating the mixed solution in the water bath at the temperature of 50-90 DEG C, and stirring for 1-2 hours; (2) performing reaction on the mixed solution at 150-350 DEG C and the pressure of 1-10MPa for 3-10 hours, cooling to room temperature after the reaction is finished, and performing solid-liquid separation to obtain a solid which is a precursor solid-phase product; (3) drying the precursor solid-phase product, and then sintering to obtain the carbon-coated lithium ferrous pyrophosphate. The method has the advantage that the reaction temperature is relatively low, and the synthesis method is simple; the prepared carbon-coated lithium ferrous pyrophosphate serving as a positive electrode material is excellent in electrochemical performance.

Description

technical field [0001] The invention belongs to the field of new energy materials, and relates to a method for synthesizing lithium iron pyrophosphate, a positive electrode active material of a lithium ion battery, in particular to a method for synthesizing carbon-coated lithium iron pyrophosphate by a hydrothermal method. Background technique [0002] Since it was proposed in 1990, the commercialization of lithium-ion batteries has achieved great success, replacing traditional lead storage, nickel-hydrogen, and nickel-cadmium batteries, and occupying a dominant position in the field of portable electronic products. As people's needs continue to increase, lithium-ion batteries are expected to play a greater role in large-scale energy storage, electric vehicles and other fields. [0003] Layered LiCoO 2 、LiNi 1 / 3 co 1 / 3 mn 1 / 3 o 2 Materials are widely used in portable energy storage devices. However, when used as large-scale energy storage and power batteries, high cost ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58
CPCH01M4/366H01M4/5825H01M4/625H01M10/0525Y02E60/10
Inventor 郑俊超欧星张宝王彦方陈晓彬杨沛
Owner CENT SOUTH UNIV
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