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High-multiplying-power type lithium iron phosphate/carbon composite material and preparation method thereof

A carbon composite material, lithium iron phosphate technology, applied in the direction of electrical components, electrochemical generators, battery electrodes, etc., can solve the problems of low electronic conductivity, slow diffusion rate, capacity performance, and fast charge and discharge rate performance. , to achieve the effects of high product crystallinity, stable cycle performance, and good high-current charge-discharge performance

Inactive Publication Date: 2014-07-02
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the limitation of its own structure, LiFePO 4 There is a low electronic conductivity (10 -10 ~10 -9 S cm -1 ) and Li + Diffusion rate is slow (~1.8×10 -14 cm 2 ·S -1 ) and other shortcomings, making it difficult for the capacity performance, fast charge and discharge and rate performance of the material to meet the requirements of the new generation of lithium-ion power batteries

Method used

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  • High-multiplying-power type lithium iron phosphate/carbon composite material and preparation method thereof
  • High-multiplying-power type lithium iron phosphate/carbon composite material and preparation method thereof
  • High-multiplying-power type lithium iron phosphate/carbon composite material and preparation method thereof

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Experimental program
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Effect test

Embodiment 1

[0019] (1) Using medium-temperature coal tar pitch as raw material, the amphiphilic carbon material was prepared by acid oxidation method. The specific preparation process is as follows: the pitch is crushed and sieved by a ball mill, and the pitch particles with a particle size of less than 150 μm are taken as the raw material. Heat 50 ml of mixed acid (prepared with 65% concentrated nitric acid and 98% concentrated sulfuric acid in a volume ratio of 3:7) to 80 °C, stir at a stirring rate of 300 r / min, add 10 g of medium temperature Coal tar pitch, reacted for 3 h, poured the reactant into 500 mL of deionized water to terminate the reaction, filtered with a vacuum filtration device, and the obtained filter cake was washed with deionized water until neutral; the obtained solid matter was added to 500 mL of concentration 1 In mol / L NaOH solution, stir at 300 r / min for 1 h at 80 °C, filter under reduced pressure, and keep the pH value of the solution always greater than 12 during...

Embodiment 2－5

[0029] The preparation method is basically the same as that in Example 1, except that 0.1896 g of pitch-based amphiphilic carbon material was added in step (1) instead of 0.1835 g of graphene oxide, 0.1449 g of sulfonated pitch, and 0.1288 g of needle coke. Amphiphilic carbon material, 0.1521 g humic acid, the needle-shaped coke-based amphiphilic carbon material is made from petroleum needle coke as raw material, according to the preparation method in step 1, and the amount of mixed acid is 100 ml have to.

[0030] XRD tested (see figure 1 ), the peak ratio 1 of the (020) peak and the (200) peak of the lithium iron phosphate / carbon composite material prepared in Example 2-5 (020) / I (200) They are 3.5, 3.6, 4.0, 4.2 respectively. It shows that the acicular coke amphiphilic carbon materials and humic acid can also be used as structure inducers and promoters.

Embodiment 6

[0032] (1) Add 0.756 g of lithium hydroxide powder to 60 ml of ethylene glycol, and ultrasonically disperse for 30 min. Under the condition of magnetic stirring, 0.6917 g of phosphoric acid with a mass concentration of 85% was added dropwise to the suspension, and the stirring was continued for 30 min to obtain a lithium phosphate suspension. 1.668 g of ferrous sulfate and 0.0948 g of pitch-based amphiphilic carbon material were added to the above suspension, and stirring was continued for 30 min.

[0033] (2) is the same as step (2) of Example 1.

[0034] (3) is the same as step (3) of Example 1.

[0035] (4) is the same as step (4) of Example 1.

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Abstract

The invention discloses a high-multiplying-power type lithium iron phosphate / carbon composite material and a preparation method thereof. The lithium iron phosphate / carbon composite material is in a structure of nanosheets which are irregular and are 25-35nm in thickness; the mass ratio of a carbon coating layer to lithium iron phosphate is (0.1-0.01):(0.9-0.99). The preparation method comprises the following steps: with lithium hydroxide, phosphoric acid and ferrous sulfate as materials, performing solvothermal reaction on the materials and a carbon source including an asphalt-based amphiphilic carbon material, and then performing coating treatment of the asphalt-based amphiphilic carbon material to obtain the lithium iron phosphate / carbon composite material with uniform carbon coating. The high-multiplying-power type lithium iron phosphate / carbon composite material disclosed by the invention has the following advantages that the process is simple, is easy to control and free from pollution; the prepared lithium iron phosphate / carbon composite material is good in orientation, fewer in defects and high in crystallinity, the discharging specific capacities under the temperatures of 10 DEG C and 30 DEG C reach 132.2 mAh.g<-1>and 113.3mAh.g<-1> respectively, the high-multiplying-power performance is good and the circulating stability is excellent.

Description

technical field [0001] The invention relates to a high-rate lithium iron phosphate / carbon composite material and a preparation method thereof, belonging to the technical field of positive electrode materials for lithium ion batteries. Background technique [0002] Polyanionic Cathode Material LiFePO 4 Since it was first proposed by the Goodenough team in 1997, it has been considered as a promising cathode material for lithium-ion batteries due to its abundant raw material reserves, low cost, environmental friendliness, high specific capacity, good safety performance and stability. The first choice for automotive power batteries. However, due to the limitation of its own structure, LiFePO 4 There is a low electronic conductivity (10 -10 ~10 -9 S cm -1 ) and Li + Slow diffusion rate (~1.8×10 -14 cm 2 ·S -1 ) and other shortcomings, making it difficult for the material's capacity performance, rapid charge-discharge and rate performance to meet the requirements of a ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/36H01M4/62
CPCH01M4/366H01M4/5825H01M4/625H01M10/0525Y02E60/10
Inventor 陈明鸣马倩倩王成扬
Owner TIANJIN UNIV
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