Fe base lithium sale compound anode materials and its making method

A composite positive electrode material and composite material technology, applied in the field of positive electrode material and its preparation, can solve the problems of low ion diffusion coefficient and electronic conductivity, low battery volume specific capacity, poor high rate discharge performance, etc. The effect of a wide range of sources and excellent processing performance

Active Publication Date: 2008-05-28
常州锂源新能源科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are two problems with this material. One is that the ion diffusion coefficient and electronic conductivity of the material are very low, resulting in poor high-rate discharge performance and low reversible specific capacity; low capacity
This greatly limits its application in practical batteries
In order to overcome the above defects, many researchers have taken appropriate methods, such as the patent US2003 / 0077514A1, which uses iron doping metal ions to improve LiFePO 4 The electron and ion conduction of the positive electrode material, but due to the addition of more carbon black in the raw material, the tap density of the material is low, which brings difficulties to the production and processing of the electrode

Method used

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  • Fe base lithium sale compound anode materials and its making method
  • Fe base lithium sale compound anode materials and its making method
  • Fe base lithium sale compound anode materials and its making method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] 8.5Kg lithium iron phosphate LiFePO 4 With 1.5Kg nickel cobalt manganese lithium LiNi 0.33 co 0.33 mn 0.33and 0.1Kg of nano-carbon are mixed evenly, put into the Q50 fusion machine of Luoyang Qixing Technology Development Co., Ltd., and carry out mechanical fusion treatment at a speed of 1100rpm for 2 hours, and then pass through Gongyi Songling Mining Machinery Co., Ltd. CXJ-100- I-type magnetic separator removes magnetic substances under a magnetic field strength of 7000 Gauss, and then sieves through a 325-mesh fine sieve and vacuum packs to obtain iron-based lithium salt composite cathode materials. The specific surface of the raw material lithium iron phosphate is 40.12m 2 / g, the tap density is 1.23g / cm 3 . As shown in Figure 1, the prepared iron-based lithium salt composite cathode material, using Cu target K α ray, wavelength 0.154056nm, obtained X-ray diffraction pattern, it can be seen from the figure that the crystal of the material is olivine structure...

Embodiment 2

[0035] 8Kg lithium ferrous phosphate and 2Kg nickel cobalt aluminum lithium LiNi 0.33 co 0.33 al 0.33 and 0.15Kg of nano-carbon are mixed evenly, put into a fusion machine for fusion treatment at 1100rpm for 2 hours, then remove the magnetic substances through a 12000 Gauss ultra-high-strength magnetic separator, and then sieve through a 325-mesh fine sieve and vacuum pack to obtain the product. The specific surface of the raw material lithium iron phosphate is 40.12m 2 / g, the tap density is 1.23cm 3 . Using the same instrument and method as in Example 1, it is measured that the material crystal is an olivine structure, the space group is Pbnm, the microscopic shape of the material is spherical or a spherical-like shape with a ratio of length to diameter of 1.8, and the average particle size is 7 μm. The specific surface area is 17.47m 2 / g, tap density 1.61g / cm 3 .

[0036] Electrodes were prepared according to the same method as in Example 1, and the electrochemical ...

Embodiment 3

[0038] 9Kg lithium ferrous phosphate and 1Kg nickel cobalt manganese lithium LiNi 0.05 co 0.05 mn 0.9 and 0.5Kg of conductive carbon black were evenly mixed, put into a fusion machine and fused for 4 hours at a speed of 200 rpm, then removed the magnetic substance through a 3000 Gauss ultra-high-strength magnetic separator, and then sieved through a 200-mesh fine sieve and vacuum-packed to obtain the product. The specific surface of the raw material lithium iron phosphate is 41.12m 2 / g, the tap density is 1.23cm 3 . Using the same instrument and method as in Example 1, it is measured that the crystal of the material is an olivine structure, the space group is Pbnm, the microscopic shape of the material is spherical or a spherical-like shape with an aspect ratio of 2.5, and the average particle size is 7 μm. The specific surface area is 18.36m 2 / g, tap density 1.65g / cm 3 .

[0039] Electrodes were prepared according to the same method as in Example 1, and the electroch...

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Abstract

The invention discloses a ferrous lithium salt composite anode material and thepreparation method thereof. The technical problems which are needed to be solved are to enhance the high-rate electricity discharging of the anode material, and the manufacturing and the processing performances of battery electrodes are improved. The ferrous lithium salt composite anode material has lithium iron phosphate, and forms the composite material by adulterated with or covered by nickel-cobalt-manganese-lithium or nickel-cobalt-aluminum-lithium material. The weight ratio of the lithium iron phosphate and the nickel-cobalt-manganese-lithium or the nickel-cobalt-aluminum-lithium material is 9 to 7 : 1 to 3, and the micro-morphology is in a sphericity , or is like a sphericity, with a ration between a horizontal length and a vertical length of 1.2 to 2.5. The crystal is in the structure of an olivine type, a space group is Pbnm, and a particle diameter is 1 to 20microns. The preparation method comprises mixture, fusion processing and screen separation. Compared with the prior art, the ferrous lithium salt composite anode material has the advantages of capable of lowering specific surface area, capable of enhancing the voltage platform of the anode material, favorable processing performance, high tap density, favorable conductivity, favorable rate discharge performance and safe performance, capable of improving high and low temperature cycling performance, and favorable compatibility with various cathodes and electrolytes.

Description

technical field [0001] The invention relates to a positive electrode material for a lithium ion power battery and a preparation method thereof, in particular to a ferrous phosphate-based lithium salt positive electrode material and a preparation method thereof. Background technique [0002] In 1997, Goodenough[J.Electrochem Soc., 144, 1997, 1188] et al. synthesized the iron-containing lithium salt LiFePO 4 , using this material as a positive electrode material for lithium-ion batteries has a higher theoretical specific capacity (175mAh / g), which is greater than that of commercialized LiCoO 2 The actual capacity of 140mAh / g. This lithium iron phosphate with olivine crystal structure has a stable working voltage (Fe 2+ / Fe 3+ The voltage relative to metal lithium is 3.4V), excellent charge and discharge platform characteristics, high capacity, stable structure, good high temperature performance and cycle performance, safe and non-toxic, low cost, small volume effect when co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/48H01M4/04B22F1/02B01J19/00C01G1/02
CPCY02E60/12Y02E60/10
Inventor 岳敏贺雪琴张万红卢英君
Owner 常州锂源新能源科技有限公司
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