Phosphate-coated nano-grade lithium iron phosphate cathode material and preparation method thereof

A cathode material, phosphate technology, applied in battery electrodes, electrical components, circuits, etc., can solve problems such as poor kinetic performance, and achieve the effects of cheap raw materials, easy availability of raw materials, and convenient manufacturing process operations.

Inactive Publication Date: 2012-12-26
BEIJING CENT PRESS UNION TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

LiFePO at room temperature 4 The electronic conductance is also much lower than other cathode

Method used

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  • Phosphate-coated nano-grade lithium iron phosphate cathode material and preparation method thereof
  • Phosphate-coated nano-grade lithium iron phosphate cathode material and preparation method thereof
  • Phosphate-coated nano-grade lithium iron phosphate cathode material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0016] Example 1

[0017] According to the molar ratio of iron, phosphorus, lithium, and aluminum of 1:1.05:1.1:0.05, weigh the mixture of iron phosphate, lithium carbonate, and aluminum phosphate, and add them to a water-based solvent containing 4% PVP by ball milling at a grinding speed of 1500r / min, ball milling for 2h. The slurry was transferred to a drying box at 80°C for vacuum drying, and the dried precursor was transferred to an inert atmosphere protection furnace with nitrogen protection. The temperature was increased to 350°C at a heating rate of 5°C / min. After holding for 5 hours, it was heated for 10 minutes. Heating rate of ℃ / min to 700℃, keep for 18h, and get LiAlP after cooling 2 O 7 Coated Nano LiFePO 4 Lithium-ion battery cathode material.

[0018] figure 1 It is a scanning electron microscope picture of the obtained sample. It can be seen from the figure that the obtained sample has uniform and fine particles, with a primary particle of about 100 nm. figure 2 L...

Example Embodiment

[0019] Example 2

[0020] Weigh iron phosphate, lithium carbonate, aluminum oxide (or aluminum acetate, aluminum nitrate) according to the molar ratio of iron, phosphorus, lithium, and aluminum of 1:1:1.02:0.01, mix them, and add them to the aqueous solvent containing 3.5% PEG. Medium ball mill, the milling speed is 800r / min, and the ball mill is 10h. The slurry was transferred to a drying box at 80℃ for vacuum drying, and the dried precursor was transferred to an inert atmosphere protection furnace to be protected by nitrogen. The temperature was increased to 350℃ at a temperature increase rate of 8℃ / min. Heating rate of ℃ / min to 710℃, keep for 14h, and get LiAlP after cooling 2 O 7 Coated Nano LiFePO 4 Lithium-ion battery cathode material. image 3 LiAlP obtained by the above method 2 O 7 Coated Nano LiFePO 4 Different discharge rate capacity test curves of cathode materials for lithium-ion batteries, 0.1C, 0.2C discharge capacity is 155mAhg -1 , 0.5C, 1C, 2C, 5C discharge cap...

Example Embodiment

[0021] Example 3

[0022] According to the molar ratio of iron, phosphorus, lithium, and vanadium of 1:1.05:1.1:0.05, weigh the ferric oxide, lithium dihydrogen phosphate, and lithium vanadate vanadium pentoxide and mix them, and add them to the content of 3% polyacrylamide. Ball milling in water-based solvent, milling speed is 1000r / min, ball milling for 10h. The slurry is transferred to spray drying, the inlet temperature is 170°C, the outlet is 80°C, the pump speed is 15Hz, and the nozzle speed is 45Hz. The dry precursor was transferred to an inert atmosphere protection furnace, and nitrogen protection was introduced. The temperature was increased to 400°C at a heating rate of 2°C / min. After holding for 8 hours, the temperature was increased to 720°C at a heating rate of 8°C / min. 12h, get Li after cooling 3 V 2 (PO 4 ) 3 Coated Nano LiFePO 4 Lithium-ion battery cathode material.

[0023] Li obtained by the above method 3 V 2 (PO 4 ) 3 Coated Nano LiFePO 4 Coated Nano LiFePO 4 ...

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Abstract

The invention relates to a phosphate-coated nano-grade lithium iron phosphate cathode material and a preparation method thereof. The invention belongs to the field of energy materials, and especially relates to the field of lithium ion battery cathode materials. The invention provides coated-type nano-grade LiFePO4 with phosphate or pyrophosphate coated on the surface, and a preparation method thereof. According to the type of materials, a lithium source compound, an iron source compound, a phosphorus source compound, and an aluminum source compound (a vanadium source compound) are adopted as raw materials; the raw materials are mixed and dispersed; and a high-temperature solid-phase method is adopted, such that a phosphate or pyrophosphate amorphous film with good lithium ion conductivity is formed on the surface of nano-grade LiFePO4. With the material, Li<+> can be easily conducted to the surface of crystal grains, such that Li<+> migration ability is improved, and the dynamic performance of the LiFePO4 material can be greatly improved.

Description

Technical field: [0001] The invention belongs to the technical field of green energy materials, and in particular relates to a lithium iron phosphate material for lithium ion batteries and a manufacturing method thereof. Background technique: [0002] Lithium-ion battery is currently a portable chemical power source with the highest specific energy. It has the advantages of high output voltage, stable discharge voltage, high energy density, low self-discharge rate, and long storage and working life. With the miniaturization of today's electronic equipment and the rapid development of electric tools, the research and application of lithium-ion batteries are getting more and more attention. For current lithium-ion batteries, the positive electrode material is one of the key materials of lithium-ion batteries as the source of lithium ions. At present, the positive electrode materials used in lithium-ion batteries are mainly lithium transition metal oxides, including LiCoO with...

Claims

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Application Information

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IPC IPC(8): H01M4/58H01M4/1397
CPCY02E60/122Y02E60/10
Inventor 马平平夏定国刘振刚陈宇胡朴
Owner BEIJING CENT PRESS UNION TECH
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