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Preparation method for high-density spherical lithium iron phosphate material

A lithium iron phosphate, high-density technology, applied in the direction of electrical components, battery electrodes, circuits, etc., can solve the problems of insignificant improvement in material conductivity, low capacity, uneven element doping, etc., and achieve the goal of doping metal ions Uniform distribution, good conductivity and rate performance, reducing the effect of ion diffusion process

Inactive Publication Date: 2014-03-12
GENERAL RESEARCH INSTITUTE FOR NONFERROUS METALS BEIJNG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

LiCoO 2 Expensive, toxic, poor safety; LiMn 2 o 4 Low capacity, poor cycle life, especially at high temperature; although ternary materials replace cobalt with part of nickel and manganese, there is still a problem of high price
The shortcomings of the three materials make it difficult to meet the requirements of electric vehicles
The disadvantages of the above method are: the obtained product has a low tap density, generally 1.0-1.3g / cm3, and the low bulk density leads to a low volume specific capacity of the product, which hinders its application in electric vehicles
Secondly, the dopant source material is ground and mixed with other substances and then calcined, the element doping is uneven, and the improvement of the conductivity of the material is not obvious

Method used

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  • Preparation method for high-density spherical lithium iron phosphate material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Prepare a mixed aqueous solution with ferrous sulfate and phosphoric acid concentrations of 1.0mol / L, and add nickel sulfate therein, and the concentration of nickel sulfate in the mixed aqueous solution with nickel sulfate added is 0.03mol / L; the prepared concentration is 2mol / L NaOH solution; prepare a hydrogen peroxide solution with a concentration of 1mol / L. Under continuous stirring conditions, the above-mentioned raw material solutions are continuously added to the reactor respectively, and the flow rate of the mixed aqueous solution of phosphoric acid and ferrous sulfate is controlled to be 0.02L / min, and the flow ratio of the mixed aqueous solution of phosphoric acid and ferrous sulfate to hydrogen peroxide is V M :V H2O2 =3:1; adjust the flow of lye, control the pH value of the reaction system to 2.50±0.05, and the temperature of the reaction system to be 45°C. After the overflowed slurry is filtered, it is washed with pure water at 40°C until the pH of the wa...

Embodiment 2

[0022] Preparation of ferrous sulfate and phosphoric acid concentration is a mixed aqueous solution of 1.5mol / L, and magnesium sulfate is added therein, the concentration of magnesium sulfate in the mixed aqueous solution of adding magnesium sulfate is 0.02mol / L; the preparation concentration is 3mol / L NaOH solution; prepare a hydrogen peroxide solution with a concentration of 1.5mol / L. Under continuous stirring conditions, the above-mentioned raw material solutions are continuously added to the reactor respectively, and the flow rate of the mixed aqueous solution of phosphoric acid and ferrous sulfate is controlled to be 0.1L / min, and the flow ratio of the mixed aqueous solution of phosphoric acid and ferrous sulfate to hydrogen peroxide is V M :V H2O2 =3:1; adjust the flow rate of lye, control the pH value of the reaction system to 1.80±0.05, and the temperature of the reaction system to be 50°C. After the overflowed slurry is filtered, it is washed with pure water at 40°C ...

Embodiment 3

[0025] Preparation of ferrous chloride and phosphoric acid concentration is a mixed aqueous solution of 1.5mol / L, and aluminum chloride is added therein, and the concentration of aluminum chloride in the mixed aqueous solution of adding aluminum chloride is 0.02mol / L; The preparation concentration is 4mol / L NaOH solution; prepare a hydrogen peroxide solution with a concentration of 1.5mol / L. Under the condition of continuous stirring, the above-mentioned raw material solution is continuously added in the reactor respectively, and the flow velocity of the mixed aqueous solution of controlling phosphoric acid and ferrous chloride is 2L / min, and the flow ratio of the mixed aqueous solution of phosphoric acid and ferrous chloride to hydrogen peroxide is V M :V H2O2 =3:1; adjust the flow rate of lye, control the pH value of the reaction system to 2.00±0.05, and the temperature of the reaction system to be 60°C. After the overflowed slurry is filtered, it is washed with pure water ...

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Abstract

A preparation method for a high-density spherical lithium iron phosphate material comprises: (1) weighing a divalent iron salt and phosphoric acid according to a molar ratio of 1:1, then weighing a doping metal salt, dissolving in deionized water, wherein the molar ratio of the doping metal ions to ferrous ions is 0.005-0.03 and the concentration of the divalent iron salt is 1-3 mol / L; (2) preparing an alkali metal hydroxide solution with a concentration of 1-10 mol / L; (3) preparing a hydrogen peroxide solution with a concentration of 1-5 mol / L; (4) respectively simultaneously continuously adding the solutions prepared in the step (1), (2) and (3) into a reaction vessel, performing filtering, cleaning, drying and screening on overflowed slurry to obtain a doped-type spherical ferric phosphate precursor; (5) adding the prepared spherical ferric phosphate precursor and an lithium source into a ball mill and performing ball milling for 1-3 h to obtain a mixture A; and (6) calcining A at the inert atmosphere at 600-800 DEG C for 8-15 h to obtain the lithium iron phosphate material. According to the preparation method, the raw material source is abundant, the production cost is low, and the prepared lithium iron phosphate material has the characteristics of being spherical, high in density and high in power.

Description

technical field [0001] The invention relates to a method for preparing a high-rate, high-density spherical lithium iron phosphate as a positive electrode material of a lithium ion battery. It belongs to the technical field of new energy material preparation. Background technique [0002] Lithium-ion battery is the third generation secondary rechargeable green battery, which has the advantages of high working voltage, small size, light weight, large specific energy, no memory effect, low self-discharge rate, long life, etc., and is widely used in portable Electronic equipment, space technology, defense industry, etc. With the increasing depletion of oil and the intensification of the environmental crisis, electric vehicles have attracted much attention as a potential substitute for gasoline-driven vehicles in the 21st century. Among them, lithium-ion batteries are used as the power source of electric vehicles, which is the development direction of electric vehicles. [0003...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58
CPCH01M4/5825H01M4/626Y02E60/10
Inventor 郭荣贵蒋文全于丽敏傅钟臻李涛
Owner GENERAL RESEARCH INSTITUTE FOR NONFERROUS METALS BEIJNG