Preparation method for spherical lithium ferric phosphate used as lithium ion battery anode material

A lithium-ion battery and lithium iron phosphate technology, which is applied in electrode manufacturing, battery electrodes, chemical instruments and methods, etc., can solve the problem of low volume specific capacity, low bulk density volume specific capacity, and low tap density of lithium iron phosphate materials, etc. problems, to achieve the effect of large-scale industrial production, simple preparation process and high tap density

Inactive Publication Date: 2009-09-30
NINGBO POLYTECHNIC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Second, the bulk density of the material is low, resulting in a low volume specific capacity of the lithium iron phosphate material
The tap density of the lithium iron phosphate cathode material prepared by this method is relatively low, and the general tap density is only 0.8-1.2g/cm 3 , than

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Weigh equal amounts of ferric nitrate and phosphoric acid, add deionized water respectively, and prepare a solution with a concentration of 0.5 mol / l. 0.5mol / l ferric nitrate aqueous solution is solution A, and 0.5mol / l phosphoric acid aqueous solution is solution B. Add polysorbate to kerosene, volume of kerosene: (volume of solution A+solution B)=5:1, mass ratio of polysorbate to kerosene is 0.5%, stir well. Add solution A dropwise to kerosene while maintaining stirring to form a water-in-oil system C. After the dropwise addition of solution A is completed, slowly add solution B to system C with constant stirring. After the addition of solution B was completed, the temperature of system C was raised to 70° C., the pH value of system C was adjusted to 2.0 with ammonia water, and the temperature was maintained for 15 minutes. The precipitate was centrifuged, washed thoroughly, and dried in an oven at 110°C to obtain spherical FePO 4 ·2H 2 O precursor.

[0024] The s...

Embodiment 2

[0027] Weigh ferric sulfate and ammonium dihydrogen phosphate in equal amounts, add deionized water respectively, and prepare a solution with a concentration of 1.0 mol / l, wherein a small amount of sulfuric acid is added to the ferric sulfate solution to keep the pH value of the solution below 1.0 . The acidic ferric sulfate aqueous solution is solution A, and the aqueous ammonium dihydrogen phosphate solution is solution B. Add sodium lauryl sulfate to diesel oil, the volume of diesel oil: volume of (solution A+solution B)=8:1, the mass ratio of sodium lauryl sulfate to diesel oil is 1%, and it is fully stirred. While maintaining stirring, add solution B dropwise to the diesel oil to form a water-in-oil system C. When the dropwise addition of solution B is completed, add solution A slowly to system C and keep stirring. After the addition of solution A was completed, the temperature of system C was raised to 75° C., the pH value of system C was adjusted to 2.2 with ammonia wa...

Embodiment 3

[0031]Weigh ferric chloride and ammonium hydrogen phosphate in equivalent amounts, add deionized water respectively, and prepare a solution with a concentration of 1.5 mol / l, wherein a small amount of hydrochloric acid is added to the ferric chloride solution to keep the pH value of the solution at 1.0 the following. Acidic ferric chloride aqueous solution is solution A, and ammonium hydrogen phosphate aqueous solution is solution B. Add sodium dioctyl succinate sulfonate to diesel oil, the volume of diesel oil: volume of (solution A+solution B)=10:1, the mass ratio of sodium dioctyl succinate sulfonate to diesel oil is 1.5%, and stir well. While maintaining stirring, add solution A dropwise to diesel oil to form a water-in-oil system C. When solution A is completely added dropwise, add solution B slowly to system C and keep stirring. After the addition of solution B was completed, the temperature of system C was raised to 80° C., the pH value of system C was adjusted to 2 wi...

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Abstract

The invention relates to a preparation method for spherical lithium ferric phosphate used as a lithium ion battery anode material. The preparation method comprises the following steps: respectively dissolving a ferric iron compound and a phosphorus source compound in deionized water to prepare a water phase solution A and a water phase solution B, and adding the solution A and the solution B slowly into organic oil to form a water-in-oil system C; washing and drying the water-in-oil system C after precipitation and centrifugal separation to obtain a spherical ferric phosphate predecessor; mixing the ferric phosphate predecessor, a lithium source compound and a carbon source compound, and calcining the mixture for 1 to 24 hours at 550 to 850 DEG C under the protection of inert gas so as to obtain the spherical lithium ferric phosphate anode material with high bulk density and the tap density of 1.5 to 2.2 g/cm3. The preparation process has simple operation and easy control, and facilitates realization of the large-scale industrialized production. In addition, the prepared spherical lithium ferric phosphate anode material has the high tap density reaching 1.5 to 2.2 g/cm3.

Description

technical field [0001] The invention belongs to the field of preparation of positive electrode materials for lithium ion batteries, in particular to a method for preparing spherical lithium iron phosphate as positive electrode materials for lithium ion batteries. Background technique [0002] Due to its high voltage, large capacity, long life and good safety performance, lithium-ion batteries have shown application prospects in many aspects from portable electronic devices to electric vehicles. One of the keys to the development of lithium-ion batteries is to find suitable electrode materials, so that the battery has a high enough lithium intercalation amount and good reversibility of lithium deintercalation to ensure the high voltage, large capacity and long life of the battery. LiCoO 2 It is currently a large-scale lithium-ion battery cathode material, and its comprehensive performance is excellent, but the material has high production cost, poor thermal stability, high t...

Claims

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Application Information

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IPC IPC(8): H01M4/04H01M4/58C01B25/45
CPCY02E60/12Y02E60/10
Inventor 袁正勇彭振博张慧波李爱元施立钦
Owner NINGBO POLYTECHNIC
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