Preparation method of lithium ion battery cathode material coated with carbon on surface

A lithium-ion battery and surface coating technology, which is applied to battery electrodes, circuits, electrical components, etc., can solve the problems of poor conductivity and high price of lithium iron phosphate, and achieve stable performance, uniform product particles, and simplified process control.

Inactive Publication Date: 2011-02-09
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among the three types of batteries, lithium cobalt oxide batteries are the most well-studied and are currently the batteries with the largest market share....

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Example 1: Use H 3 PO 4 , FeSO 4 , Ammonia and carbohydrates as raw materials, directly use concentrated H 3 PO 4 Carbonized carbohydrate process

[0041] (1) Partial carbonization of carbohydrates to form porous carbon materials

[0042] Take a certain amount of 98% H first 3 PO 4 It is added to the reactor, and then a saturated aqueous solution of carbohydrates with a mass of 20% is added to it, and the reaction liquid is heated to 100-120°C and maintained for more than 2 hours. During this period, the carbohydrate is partially carbonized to form a carbon material with a porous structure.

[0043] Press H 3 PO 4 And FeSO 4 ·7H 2 Weigh FeSO with an O molar ratio of 1:1 4 ·7H 2 O, add water to dissolve and add to the above reaction solution, stir to make it evenly mixed, and maintain the temperature of the suspension at 20-50°C.

[0044] (2) NH in porous carbon materials 4 FePO 4 Synthesis

[0045] The suspension obtained in the previous step is added with ammonia water (the mol...

Embodiment 2

[0050] Example 2: Use H 3 PO 4 , FeSO 4 , Ammonia and carbohydrates as raw materials, using concentrated H 3 PO 4 Process for carbonizing carbohydrates with mixed liquid of ferrous salt

[0051] This embodiment is completely the same except that the carbohydrate carbonization step is different from the above. Therefore, only the carbohydrate carbonization step is detailed.

[0052] Take a certain amount of 98% H first 3 PO 4 Add to the reactor and press H 3 PO 4 And FeSO 4 ·7H 2 Weigh FeSO with an O molar ratio of 1:1 4 ·7H 2 O, weigh carbohydrates at 20% of the mass of phosphoric acid, mix them and add appropriate amount of water to make it a clear solution. The reaction solution is heated to 100-120°C and maintained for 2 hours, during which the carbohydrate is partially carbonized to form a carbon material with a porous structure, Fe 2+ And PO 4 3- In the porous structure and solution of carbon materials.

[0053] The above solution reacts with ammonia to form NH in porous carbon...

Embodiment 3

[0054] Example 3: Use H 3 PO 4 , Other ferrous salts, ammonia and carbohydrates as raw materials

[0055] The FeSO in the above examples 1 and 2 4 Change to other ferrous salts, such as ferrous ammonium sulfate, ferrous chloride, ferrous acetate, etc., and other operation methods remain unchanged, and LiFePO with uniform carbon coating on the surface can be synthesized 4 .

[0056] The generated by-product ammonium salt, if it is ammonium nitrate, ammonium chloride, etc., can be sold directly as fertilizer; if it is acetate, it can be sold as a chemical raw material after purification.

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Abstract

The invention provides a preparation method of a lithium ion battery cathode material coated with carbon on the surface, providing a low-cost line for stably producing LiFePO4 and batteries thereof. The preparation method of the material comprises the following three steps of: partially carbonizing carbohydrate, preparing NH4MPO4 in a porous carbon material and preparing YMPO in the porous carbon material, wherein the Y element is Li element or alkali metal elements of Na and K or the combination of the elements, M is a divalent transition metal element ion or a certain MxN1-x containing the combination of metal elements of other valences, x is not smaller than 0 and is smaller than 1, and N is a trivalent transition metal element ion or a doped metal ion of other valences. Compared with other process lines, the process line of the invention has lower requirements for process control conditions, the product can have evener particles and stabler performance by synthesizing the LiFePO4 in a porous channel which is formed by carbonizing the carbohydrate, and the only two byproducts in the production process of the LiFePO4 can be favorably recycled.

Description

Technical field [0001] The invention belongs to the field of preparation of lithium ion battery cathode materials. It discloses a stable and low-cost production of YMPO 4 (LiFePO 4 ) Process route. Background technique [0002] Compared with lead-acid, nickel-cadmium, and nickel-hydrogen batteries, lithium-ion batteries have the advantages of high energy density and environmental friendliness. Currently, lithium-ion batteries are mainly used in small portable devices, such as notebook computers, mobile phones, digital cameras, and so on. However, with the increase in urban personal car ownership and the increase in urban air pollution, people hope to electrify internal combustion engine vehicles. Because the electrification of internal combustion engine vehicles can directly bring two benefits, one is the reduction of air pollution and noise pollution, and the other is that charging electric vehicles at night can make use of the excess electricity in the city at night and obtai...

Claims

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Application Information

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IPC IPC(8): H01M4/1397
CPCY02E60/122Y02E60/10
Inventor 雷立旭赵雯曲丽敏戴海燕
Owner SOUTHEAST UNIV
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