Synthetic method for high-capacity sulfurized lithium iron phosphate positive electrode material

A technology of lithium iron phosphate sulfide and cathode material, which is applied in battery electrodes, electrochemical generators, electrical components, etc., can solve the problems of low conductivity, affect performance capacity, and have not been solved, and achieve good conductivity and tight compounding. , the effect of structural stability

Inactive Publication Date: 2018-06-22
北京锦锂盛元科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this material also has shortcomings. Compared with ternary materials, the energy density of lithium iron phosphate is low, while lithium-sulfur batteries using sulfur as the positive electrode material have higher theoretical specific capacity of the material and higher theoretical specific energy of the battery, respectively reaching 1675m Ah / g and 2600Wh / kg, which are more than ten times the energy density of lithium iron phosphate batteries, have received more attention and research, and have broader application prospects
However, the conductivity of the sulfur electrode is extremely low, and problems such as sulfur dissolution seriously affect its performance, especially the capacity. At present, it is mainly improved by carbon-coated junctions and other methods, but the problems have not been resolved.
[0003] The invention provides a synthesis method of high-capacity sulfurized lithium iron phosphate / carbon-sulfur composite material, so that lithium iron phosphate and sulfide can be perfectly compounded, and the problem of low electrical conductivity of the two materials is comprehensively improved from the structure. The structure stabilizes the stability of the sulfur electrode and improves the electrochemical performance of the sulfur electrode material

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0008] Embodiment 1 Take by weighing 84g of monohydrate lithium hydroxide, 115g of ammonium dihydrogen phosphate, 278g of ferrous sulfate heptahydrate, mix and stir evenly after being made into a solution, weigh 30g of monohydrate glucose and join in the sizing solution, and then weigh Take 1.6g Tween 20 and add it to the above slurry solution, disperse it by ball milling for 2 hours, and control the particle size in the slurry below 300nm. hours, the reaction slurry product was obtained, and the product was spray-dried under the protection of nitrogen to obtain a precursor material, which was sintered at 550° C. for 6 hours in a nitrogen atmosphere. After sintering, 16 g of glucose and 120 g of deionized water were added to the sintered material. After ball milling and dispersing for 3.5 hours, the slurry was spray-dried, and the dried material was sintered in a nitrogen atmosphere at 770°C for 8 hours to obtain a high-capacity lithium iron phosphate / lithium sulfide sulfur-car...

Embodiment 2

[0009] Example 2 Weigh 126g of lithium hydroxide monohydrate and 115g of ammonium dihydrogen phosphate, mix and stir evenly after making a 50% solution, weigh 120g of iron disulfide and add the above solution, after stirring evenly, weigh 20g of ascorbic acid and add it to the In the slurry solution, weigh 1.6g Tween 20 and add it to the above slurry solution, disperse it by ball milling for 2 hours, and control the particle size in the slurry to be below 200nm. After the ball milling, transfer the slurry into the hydrothermal reaction kettle, 110°C, hydrothermal reaction for 2 hours, the reaction slurry product was obtained, the product was spray-dried under the protection of nitrogen to obtain the precursor material, the precursor material was sintered at 450°C in nitrogen atmosphere for 2 hours, and 10g of glucose was added to the sintered material , add 120g of deionized water, disperse by ball milling for 3.5h, then spray dry the slurry, and sinter the dried material at 77...

Embodiment 3

[0010] Embodiment 3 Take lithium carbonate 74g, 85% phosphoric acid 116g, ferrous sulfate heptahydrate 278g, mix and stir after being made into 50% solution, weigh 15g of sucrose and join in the sizing solution, then weigh 1.6g Add Tween 20 to the above slurry solution, disperse by ball milling for 2 hours, and control the particle size in the slurry to be below 500nm. After the ball milling, transfer the slurry into a hydrothermal reaction kettle, and conduct a hydrothermal reaction at 105°C for 2 hours to obtain The slurry product of the reaction is spray-dried under the protection of nitrogen to obtain the precursor material. The precursor material is sintered at 550°C for 6 hours in a nitrogen atmosphere. After sintering, 32 g of glucose and 120 g of deionized water are added to the material, and the ball mill is dispersed for 4 hours. , and then the slurry was spray-dried, and the dried material was sintered at 770° C. in a nitrogen atmosphere for 8 hours to obtain a high-...

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PUM

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Abstract

The invention provides a synthetic method for a high-capacity sulfurized lithium iron phosphate positive electrode material. The synthetic method comprises the following steps: with a water-soluble lithium-source compound, a ferrous-sulfide-source compound and a phosphorus-source compound as main reactants, adding a surface additive and a carbon-source reducing agent, and carrying out grinding anduniform mixing in a water phase; carrying out a low-temperature hydrothermal reaction and then carrying out drying to obtain a precursor of sulfurized lithium iron phosphate; and subjecting the precursor to calcining under the protection of high-temperature nitrogen gas to obtain the sulfurized lithium iron phosphate/carbon-sulfur composite positive electrode material.

Description

technical field [0001] The invention relates to a preparation method of a cathode material of a lithium ion battery, which belongs to the technical field of new energy materials. Background technique [0002] Lithium-ion battery is a kind of green high-energy battery. It has developed very rapidly in recent years and is widely used in various portable electronic products and communication tools. It also has a good application prospect in electric vehicles. Among them, lithium iron phosphate, as one of the positive electrode materials of lithium batteries, has been excellently applied for its high cycle life, high safety performance and reliability. However, this material also has shortcomings. Compared with ternary materials, the energy density of lithium iron phosphate is low, while lithium-sulfur batteries using sulfur as the positive electrode material have higher theoretical specific capacity of the material and higher theoretical specific energy of the battery, respecti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/58H01M4/587H01M10/0525
CPCH01M4/364H01M4/38H01M4/5825H01M4/587H01M10/0525Y02E60/10
Inventor 不公告发明人
Owner 北京锦锂盛元科技有限公司
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