Carbon coated granularity controllable spherical lithium ferric phosphate composite positive pole material and preparation thereof

A composite cathode material, a technology of lithium iron phosphate, which is applied in the field of material preparation, carbon-coated particle size controllable spherical lithium iron phosphate composite cathode material, and can solve the problems of complex preparation process, large particle size of lithium iron phosphate, and difficulty. , to achieve uniform particle size distribution, adjustable particle size, and reduce production costs.

Inactive Publication Date: 2009-04-29
李庆余 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, lithium iron phosphate has the following obvious disadvantages: (1) Fe in the synthesis 2+ easily oxidized to Fe 3+ , it is not easy to obtain single-phase lithium iron phosphate; (2) lithium ions are difficult to diffuse in lithium iron phosphate, resulting in low utilization of active materials; (3) the conductivity of lithium iron phosphate itself is also very low, resulting in its high rate Poor discharge performance
In this type of synthetic method, the technological process is relatively complicated, and due to the use of more expensive reagents such as hydrogen peroxide and lithium iodide, the production cost of the product is increased.
[0008] Among the above-mentioned existing synthetic methods, the particle size of lithium iron phosphate synthesized by the high-temperature solid-phase method is relatively large, and the electrochemical performance is not satisfactory. Although the hydrothermal method can control the particle size, it is difficult to industrialize production; the sol-gel method and The performance of lithium iron phosphate material synthesized by chemical lithium intercalation method is ideal, but its preparation process is more complicated, the production cycle is longer, and the production cost is also higher

Method used

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  • Carbon coated granularity controllable spherical lithium ferric phosphate composite positive pole material and preparation thereof
  • Carbon coated granularity controllable spherical lithium ferric phosphate composite positive pole material and preparation thereof
  • Carbon coated granularity controllable spherical lithium ferric phosphate composite positive pole material and preparation thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Weigh 798.45g Fe 2 o 3 , 1039.3gLiH 2 PO 4 , 213.9g of sucrose, and 8206.75g of distilled water were placed in a stirring mill, and stirred and ground for 24 hours at 400 rpm to obtain a yellow suspension with a solid content of 20%, which was the precursor solution; the precursor solution was continuously stirred, Under the condition of inlet pressure 0.8MPa, feed rate 2L / min, carry out spray drying, spray inlet temperature is 200 ℃, outlet temperature is 70 ℃, obtains light yellow precursor powder; Precursor powder is put into nitrogen (gas flow rate 2L / min) in the protected pusher kiln, the temperature was raised at a rate of 2°C / min, and the temperature was pre-decomposed at 400°C for 5 hours, and then the temperature was raised to 800°C at the same rate, and then heat-preserved and calcined for 12 hours, and the sample was cooled with the furnace to At room temperature, the carbon-coated spherical lithium iron phosphate composite positive electrode material with...

Embodiment 2

[0038] Weigh 798.45g Fe 2 o 3 , 1039.3gLiH 2 PO 4 , 213.9g sucrose, and 11622g distilled water were placed in the stirring mill, and stirred and ground for 20 hours with 400 rev / min to obtain a yellow suspension with a solid content of 15%, that is, the precursor solution; the precursor solution was continuously stirred, and the Inlet pressure 1.0MPa, spray drying under the condition of feed rate 1L / min, spray inlet temperature is 180 ℃, outlet temperature is 80 ℃, obtains pale yellow precursor powder; Precursor powder is put into argon (gas Flow rate 2L / min) protected pusher kiln, temperature was raised at a rate of 3°C / min, pre-decomposed at 400°C for 5 hours, and then heated to 800°C at the same rate, and then calcined for 12 hours, and the sample was cooled with the furnace to At room temperature, the carbon-coated spherical lithium iron phosphate composite positive electrode material with controllable particle size can be obtained.

[0039] Take by weighing the LiFePO...

Embodiment 3

[0041] Weigh 808.04g Fe(NO 3 ) 3 9H 2 O, 209.8gLiOH·H 2 O, 576.47g85%H 3 PO 4 , 233.2g of glucose and starch, and 7310g of water were placed in a stirring mill, and stirred and ground for 15 hours at 200 rpm to obtain a yellow suspension with a solid content of 25%, that is, the precursor solution; the precursor solution was continuously stirred , under the conditions of inlet pressure 0.6MPa and feed rate 0.5L / min, spray drying is carried out, the spray inlet temperature is 220°C, and the outlet temperature is 60°C to obtain light yellow precursor powder; put the precursor powder into nitrogen In a rotary kiln protected by hydrogen and hydrogen (gas flow rate 2L / min), the temperature was raised at a rate of 5°C / min, pre-decomposed at 360°C for 8 hours, and then heated to 700°C at the same rate, and then calcined for 18 hours. The furnace was cooled to room temperature, and the carbon-coated spherical lithium iron phosphate composite cathode material was obtained. The pa...

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Abstract

The invention discloses a carbon-coated granularity controllable sphere lithium iron phosphate compound anode material and a preparation method thereof, the steps of the preparation method is as follows: 1) the Fe<3> compound is weighted according to mol ratios as below: 1.95-2.05 of the Fe<3> compound, 1.95-2.05 of lithium source compound, 0.01-0.2 of phosphorus source compound and 2 of carbon source; 2) defined amount water is added into the Fe<3> compound, the lithium source compound, the phosphorus source compound and the carbon source, and is mixed and placed into a stirring grinder for grinding, thus obtaining precursor solution; 3) a precursor solution is granulated by spraying and drying for obtaining yellow precursor solution powder; 4) the precursor solution powder is calcined under the condition of atmosphere protection and is cooled. By adopting the spraying and drying, the obtained sphere powder granularity is evenly distributed and the size of the granularity can be adjustable; glucide is taken as the carbon source, thus achieving the purpose of thinning the particles and improving the product purity and performance; and the synthesis technique is simple, the source of the raw material is wide, thus greatly reducing the manufacturing cost.

Description

(1) Technical field: [0001] The invention relates to the technical field of lithium ion battery cathode materials, in particular to a carbon-coated particle size-controllable spherical lithium iron phosphate composite cathode material and a preparation method for the material. (two) background technology: [0002] As a new generation of green high-energy batteries, lithium-ion batteries have many advantages such as high working voltage, high energy density, good cycle performance, small self-discharge, no memory effect, and wide operating temperature range. They are widely used in mobile phones, notebook computers, UPS, etc. , camcorders, various portable electric tools, electronic instruments, weapons and equipment, etc., also have good application prospects in electric vehicles, and are considered to be high-tech products that are of great significance to the national economy and people's lives in the 21st century. Cathode materials are an important part of lithium-ion bat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/04B01J19/00B22F9/16B22F1/02
CPCY02E60/12Y02E60/10
Inventor 李庆余王红强颜志雄张安娜
Owner 李庆余
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