Lithium ion battery positive electrode lithium iron pyrophosphate preparation method

A technology for lithium iron pyrophosphate and lithium-ion batteries, which is applied to battery electrodes, non-aqueous electrolyte battery electrodes, circuits, etc. It can solve the problems that the particle size cannot be further reduced, the performance of the positive electrode material is not good, and the mixing of raw materials is uneven. Achieve the effect of good consistency, uniform molecular level and easy storage

Inactive Publication Date: 2016-06-08
CHINA ELECTRONIC TECH GRP CORP NO 18 RES INST
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Problems solved by technology

But its shortcoming is: this invention utilizes three raw materials to be mixed in solid state and then sintered. This method has the inherent disadvantages of solid-phase method, that is, raw material mixing is not uniform, and batch consistency is poor. In addi...

Method used

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  • Lithium ion battery positive electrode lithium iron pyrophosphate preparation method
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  • Lithium ion battery positive electrode lithium iron pyrophosphate preparation method

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preparation example Construction

[0026] The preparation method of lithium iron phosphate lithium iron battery cathode material is characterized in that it comprises the following preparation steps:

[0027] Step 1 Preparation of small volume transparent gel

[0028] After mixing the lithium source compound, iron source compound and phosphorus source compound according to the stoichiometric ratio Li:Fe:P=2:1:2, add a solvent to form a transparent solution containing lithium, phosphorus, and iron compounds; place the transparent solution in Evaporate under reduced pressure in the evaporator at 60°C-90°C and the pressure is less than -0.098Mpa to obtain a small-volume transparent gel;

[0029] Step 2 Material heat treatment

[0030] Place the small-volume transparent gel made in step 1 in a heating device, raise the temperature to 450°C-550°C in an inert atmosphere, and perform pre-decomposition for 0.5-4 hours; continue to heat up to 820°C-875°C in an inert atmosphere, After sintering for 0.5-2 hours and natu...

Embodiment 1

[0036] Step 1: After mixing lithium nitrate, iron nitrate and phosphoric acid according to the stoichiometric ratio Li:Fe:P=2:1:2, add isopropanol to form a transparent solution containing lithium, phosphorus and iron compounds; place the transparent solution in Evaporate under reduced pressure in an evaporator at 80°C and a pressure of -0.1Mpa to obtain a small-volume transparent gel;

Embodiment 2

[0038] Step 1: After mixing lithium sulfate, ferrous sulfate and phosphoric acid according to the stoichiometric ratio Li:Fe:P=2:1:2, add glycolic acid to form a transparent solution containing lithium, phosphorus and iron compounds; place the transparent solution in Evaporate under reduced pressure in an evaporator at 65°C and a pressure of -0.098Mpa to obtain a small-volume transparent gel;

[0039] Step 2: Material heat treatment

[0040] Place the small-volume transparent gel made in step 1 in a preheater, raise the temperature to 500°C in a nitrogen atmosphere, and perform low-temperature pre-decomposition for 1 hour; raise the temperature to 850°C in a high-temperature sintering furnace in a nitrogen atmosphere, and perform 1 Hours of high-temperature sintering and natural cooling complete the manufacturing process of lithium iron phosphate lithium ion battery cathode material of the present invention.

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Abstract

The present invention relates to a lithium ion battery positive electrode lithium iron pyrophosphate preparation method, which comprises: 1, mixing a lithium source-containing compound, an iron source-containing compound and a phosphorus source-containing compound, adding a solvent to form a transparent solution containing the lithium compound, the phosphorus compound and the iron compound, placing the transparent solution into an evaporator, and carrying out pressure reducing evaporation to obtain a small volume transparent gel; and 2, carrying out pre-decomposition and high temperature sintering on the small volume transparent gel, and naturally cooling so as to complete the lithium ion battery positive electrode lithium iron pyrophosphate preparation process. According to the present invention, the material synthesized through the wet sol-gel is sequentially subjected to pressure reducing evaporation, pre-decomposition and sintering so as to achieve the uniform molecular level of the raw material mixing, the material synthesis uniformity is good, the particle size is small, the rate performance is good, and the initial charge-discharge efficiency and the discharge capacity are high; and the inexpensive lithium source, the inexpensive iron source, the inexpensive phosphorus source and the doped elements are used so as to achieve the cheap material price, and the materials are easy to store.

Description

technical field [0001] The invention belongs to the technical field of cathode materials for lithium ion batteries, and in particular relates to a preparation method of lithium iron phosphate, an anode material for lithium ion batteries. Background technique [0002] Lithium-ion battery is a device that converts chemical energy into electrical energy through chemical reactions. It is one of the important ways of energy storage and conversion. It has been widely used in almost every field. It is the best way to alleviate the current energy crisis and reduce environmental pollution. important product. Among the secondary batteries, lithium-ion batteries have quickly become the rechargeable source of today's portable electronic products due to their advantages such as high working voltage, long cycle life, large capacity, small size, small self-discharge, no memory effect, and less environmental pollution. preferred. For lithium-ion batteries, the cathode material has a decis...

Claims

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Application Information

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IPC IPC(8): H01M4/13H01M4/58
Inventor 许寒丁飞刘兴江卢志威彭庆文任丽彬
Owner CHINA ELECTRONIC TECH GRP CORP NO 18 RES INST
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