Spherical porous high-density LiFePO4 powder and process for preparing same

A high-density, PO43- technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of increased production costs, long holding time, high roasting temperature, etc.

Inactive Publication Date: 2006-09-27
JIANGSU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the precursor prepared by it is a simple solid-phase mixture of various substances, and the grain size is

Method used

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  • Spherical porous high-density LiFePO4 powder and process for preparing same
  • Spherical porous high-density LiFePO4 powder and process for preparing same
  • Spherical porous high-density LiFePO4 powder and process for preparing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Press Fe 2+ :PO 4 3- Mix the ferrous sulfate solution and the ammonium phosphate solution at a molar ratio of 3:2, adjust the pH value of the mixed solution to 7.0 with ammonia water, and mechanically stir for 40 hours to form a ferrous phosphate precipitate; wash the obtained ferrous phosphate precipitate with water for 3 to 5 times , filtered, vacuum-dried at 60°C and kept warm for 20 hours to obtain a spherical porous structure amorphous ferrous phosphate hydrate powder with a particle size of 1 to 25 μm; the obtained spherical porous structure amorphous ferrous phosphate hydrate powder was placed in a Ionized water, add lithium hydroxide and phosphoric acid solution to it, and make Li + : Fe 2+ :PO 4 3- The molar ratio is 1:1:1, electromagnetic stirring for 3 hours, and filtration to obtain the precursor powder of lithium phosphate-wrapped amorphous ferrous phosphate; the precursor powder is placed in an inert gas roasting tube furnace, and nitrogen is introduc...

Embodiment 2

[0047] Prepare ferrous sulfate solution of 1.10mol / L and ammonium dihydrogen phosphate solution of 0.73mol / L, adjust the flow rate of the metering pump to 8ml / min, input the equal flow rate of the above solution into the reactor filled with 4L water in advance, pass NaOH controls the pH value of the reaction solution at 4.5, the mother liquor flows into the discharge barrel from the overflow, the electromagnetic stirring continues the reaction for 10h, and the feeding is stopped. The liquid in the discharge barrel is washed with water several times, then filtered, placed in vacuum drying at 80° C. for 5 hours, and ground to obtain spherical porous ferrous phosphate hydrate powder with a particle size of 2-30 μm. Spherical porous structure hydrated ferrous phosphate powder is placed in deionized water, lithium hydroxide and phosphoric acid solution are added thereto, and Li + : Fe 2+ :PO 4 3- The molar ratio is 1:1:1, after 15 hours of mechanical stirring, sucrose is added t...

Embodiment 3

[0049] Prepare 0.42mol / L ferrous sulfate solution and 0.28mol / L ammonium phosphate solution, adjust the flow rate of the metering pump to 10ml / min, input the equal flow rate of the above solution into the reactor filled with 4L water in advance, and control it with ammonia water The pH value of the reaction solution was 6.5, and the mother liquor flowed into the discharge barrel from the overflow, and the reaction was continued for 30 hours, and the feeding was stopped. The liquid in the discharge barrel is washed with water several times, then filtered, placed in vacuum drying at 70° C. for 10 hours, and spherical porous ferrous phosphate hydrate powder with a particle size of 1-25 μm is obtained. Spherical porous structure hydrated ferrous phosphate powder is placed in deionized water, lithium hydroxide and phosphoric acid solution are added to it, and Li + : Fe 2+ :PO 4 3- The molar ratio was 1:1:1, electromagnetic stirring was performed for 8 hours, and rotary evaporati...

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Abstract

The invention refers to a method which prepare high-density global c, using ferrous salt, phosphorus acid, ammonia and lithium hydrate, lithium phosphate as initial material, firstly, adding ferrous salt solution and phosphor fountain in reactor by metering pump, adjusting pH value in reactor by queous alkali, occurring deposition react, the precipitate overflowing along with mother liquid, washing, filtrating and drying the effluent deposit would receive global hydrated ferrous phosphate; confecting ferrous phosphate and lithium phosphate suspend, getting mole ratoo of Li+:Fe2+:PO43- is 1:1:1, then adding carbon fountain, getting lithium phosphate and ferrous phosphate mix prodromal body after intimate mixing, solid-liquid separation; Calcining prodromal body for 5-30h in 500-800Deg C inertia and deoxidized atmosphere, cooling to room temperature with furnace, then getting global ferric lithium phosphate powder. The grain-size range of this powder is 0.5-30 mum, particle mean size is 8-13 mum, tap density is as high as 1.5- 2.0g/cm3, first discharge capacity is bigger than 120mAh/g, discharge voltage flat roof is 3.4V, hasing fine application foreground.

Description

technical field [0001] The invention relates to a preparation technology of lithium battery cathode material, in particular to a precipitation method for preparing spherical high-density lithium ion battery cathode material LiFePO 4 Powder process. Background technique [0002] LiFePO 4 It is a kind of cathode material for lithium-ion batteries, with a mass specific capacity of 170mAh / g and a voltage platform of 3.5V. LiFePO 4 with LiCoO 2 , LiMnO 2 , LiNiO 2 Compared with other lithium battery positive electrode materials, it has the best thermal stability (it can still maintain the same structure at 350°C), and has the lowest solubility in the electrolyte (and the solubility hardly changes with temperature). Charge and discharge at high rate, Li + Almost 100% intercalation / deintercalation possible, and LiFePO 4 It does not contain precious elements, the source of raw materials is wide, and the cost is low. Therefore, LiFePO 4 It is expected to replace expensive Li...

Claims

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Application Information

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IPC IPC(8): C01B25/45H01M4/58
CPCY02E60/10
Inventor 沈湘黔占云周建新景茂祥
Owner JIANGSU UNIV
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