Preparation method of carbon-coated and doped lithium-iron phosphate

A technology of lithium ferrous phosphate and iron source, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of complex solid-liquid phase synthesis conditions, difficult to meet large-scale preparation of materials, etc., and reduce control conditions. Effect

Inactive Publication Date: 2012-06-27
IRICO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The properties of the materials prepared by the above liquid-phase methods have been improved to a certain extent. This is because the synthesis conditions of the solid-liquid phase are complex and the proces

Method used

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  • Preparation method of carbon-coated and doped lithium-iron phosphate
  • Preparation method of carbon-coated and doped lithium-iron phosphate
  • Preparation method of carbon-coated and doped lithium-iron phosphate

Examples

Experimental program
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Effect test

Embodiment 1

[0029] The preparation method of carbon-doped lithium iron phosphate comprises the following steps:

[0030] 1) by mass parts, weigh 0.738 parts of Li 2 CO 3 , 4.457 parts FePO 4 , 0.308 parts of glucose, mixed and put into a ball mill tank, ball milled for 2 hours, and mixed evenly;

[0031] 2) Put the mixed powder obtained in step 1) into a high-temperature furnace, heat and calcinate under a nitrogen atmosphere, and the pressure of the furnace cavity is 1.5×10 5 Pa, the temperature is 600°C, calcined for 3 hours;

[0032] 3) Lower the temperature of the high-temperature furnace to 500°C, introduce air, keep warm for 5 hours, then cool down to room temperature, and take out the intermediate product;

[0033] 4) Add 0.308 g of glucose to the mixed powder obtained in step 3), ball mill it for 2 hours after mixing, then put it into the high-temperature furnace again, and calcinate it under a nitrogen atmosphere at a pressure of 1.2×10 5 Pa, the temperature is 700°C, the ca...

Embodiment 2

[0046] The preparation method of carbon-doped lithium iron phosphate comprises the following steps:

[0047] 1) Weigh 1mol of Li 2 CO 3 , 1mol of Fe 2 o 3 , 1mol of ammonium dihydrogen phosphate and 20g of glucose were mixed and put into a ball mill jar, ball milled for 2 hours, and mixed evenly.

[0048] 2) Put the mixed powder obtained in step 1) into a high-temperature furnace and heat it under a nitrogen atmosphere. The pressure of the furnace cavity is 1.5×10 5 Pa, the temperature is 600°C, and the treatment is 3 hours;

[0049] 3) Lower the temperature of the high-temperature furnace to 500° C., introduce air, keep the temperature for 5 hours, and take out the materials when the temperature is lowered to room temperature.

[0050] 4) Add 5 grams of glucose to the mixed powder obtained in step 3), ball mill for 2 hours, put the material back into the high-temperature furnace, and perform high-temperature treatment in a nitrogen atmosphere with a pressure of 1.2×105Pa...

Embodiment 3

[0052] The preparation method of carbon-doped lithium iron phosphate comprises the following steps:

[0053] 1) LiH 2 PO 4 , FeC 2 o 4 , FeO was mixed in a molar ratio of 1: (0.96-0.99): (0.01-0.04) in an equimolar ratio, and 10 grams of sucrose was added.

[0054] 2) Put the mixed powder obtained in step 1) into a high-temperature furnace, heat it under an argon atmosphere for pretreatment, and the pressure of the furnace cavity is 1.5×10 5 Pa, the temperature is 500°C, pretreatment for 3 hours;

[0055] 3) Lower the temperature of the high-temperature furnace to 450° C., let in air, keep the temperature for 5 hours, and then take out the material when the temperature is lowered to room temperature.

[0056] 4) Add 5 grams of sucrose to the mixed powder obtained in step 3), ball mill for 2 hours, put the material back into the high-temperature furnace, and perform high-temperature treatment under an argon atmosphere with a pressure of 1.5×10 5 Pa, the temperature is 650...

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Abstract

The invention discloses a preparation method of carbon-coated and doped lithium-iron phosphate, which is a synthetic process of reduction, oxidation and reduction crushing and comprises the following steps of: synthesizing a lithium-iron phosphate crude product by adopting a cheap iron sources, a phosphate-group source and a lithium source through high-temperature reduction, then crushing and refining large grains in the crude product through an oxidizing reaction, and finally obtaining a lithium-iron phosphate material with excellent electrochemical performance through heat processing and reduction after being mixed with a reduced carbon source. The large lithium-iron phosphate grains in the lithium-iron phosphate material prepared by the invention is refined, and the lithium-iron phosphate with uniform and fine grains is prepared from the refined grains through carbon-coated reduction; and because the grains of the raw material are small and are uniformly mixed, the grains can be converted into lithium-iron phosphate crystals with fine grains at a lower temperature.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and relates to a preparation method of carbon-doped lithium iron phosphate. Background technique [0002] Since the advent of lithium-ion batteries in 1991, their cathode materials have been a hot spot in material research. The current research mainly focuses on transition metal oxides containing lithium, and the transition metals are mainly nickel, cobalt, and manganese. In recent years, due to the abundance of iron in the earth's crust, its cheap price, and environmental friendliness, based on Fe 2+ / Fe 3+ Redox-coupled substances have aroused great interest, so people are racing to study iron-containing lithium salts to replace current cathode materials. [0003] In 1999, J.B.Goodenough and others from the University of Texas in the United States obtained the patent right of US Patent No.591382de lithium iron phosphate lithium battery cathode material, with 0.05mA / cm 2 The sm...

Claims

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Application Information

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IPC IPC(8): H01M4/58C01B25/45
CPCY02E60/12Y02E60/10
Inventor 刘涛涛
Owner IRICO
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