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Low-temperature carbon-coated composite material, its preparation method and application

A technology of composite materials and coating materials, which is applied in the field of materials, can solve the problems of high-valence elements being reduced and the degree of graphitization is not high, and achieve the effects of increasing specific capacity and specific energy, ensuring cyclicity, and improving electronic conductance

Active Publication Date: 2013-03-06
INST OF PHYSICS - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In order to solve the problems in the prior art that the carbon coating temperature is relatively high, the degree of graphitization obtained is not high, and some high-valence elements are easily reduced, the purpose of the present invention is a low-temperature carbon-coated composite material whose rate performance and cycle performance are greatly improved; another object of the present invention is to provide a method for preparing low-temperature carbon-coated composite materials, which can prepare said composite materials at low temperatures; another object of the present invention is to provide a low-temperature Application of carbon-coated composite materials on lithium batteries; another object of the present invention is to provide a secondary lithium battery comprising low-temperature carbon-coated composite materials

Method used

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  • Low-temperature carbon-coated composite material, its preparation method and application
  • Low-temperature carbon-coated composite material, its preparation method and application

Examples

Experimental program
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Effect test

Embodiment 1

[0051] Example 1: Lithium titanate battery without low-temperature carbon coating

[0052] According to Li 4 Ti 5 o 12 Materials, acetylene black and polyvinylidene fluoride (PVDF) account for 80wt%, 10wt% and 10wt% respectively to prepare electrodes as an electrode of the half-cell. The counter electrode uses metal Li, and 1mol / L LiPF 6 / Ethylene carbonate (EC)-diethylene carbonate (DEC) as the electrolyte, wherein the volume ratio of EC and DEC is 1:1, assembled into a battery in a glove box and tested its charge and discharge performance, the voltage range is 1-3V, test results see Image 6 and Figure 7 , indicating that the lithium titanate material without low-temperature carbon coating has poor rate performance, with a capacity of only 30mAh / g at 10C rate, 60mAh / g capacity at 5C rate, and only 120mAh / g capacity at 2C rate after 120 cycles. is 100mAh / g.

Embodiment 2

[0053] Example 2: Low-temperature carbon-coated lithium titanate battery

[0054] First, the C source 10,10'-dibromo-9,9'-bianthrene was dissolved in tetrahydrofuran to obtain a clear solution, and the Li 4 Ti 5 o 12 According to the mass ratio of C source to 9:1, add it to the above solution, stir evenly, and heat to 40°C to completely volatilize tetrahydrofuran to obtain Li 4 Ti 5 o 12 and C source precursors, the precursors were heated in argon at 400°C, and kept for 2 hours to obtain low-temperature carbon-coated Li 4 Ti 5 o 12 composite material.

[0055] Will wrap the former Li 4 Ti 5 o 12 and low-temperature carbon-coated Li 4 Ti 5 o 12 Composites were tested by XRD ( figure 1 ), the results show that the coating does not change the Li 4 Ti 5 o 12 Structure. Low-temperature carbon coated Li 4 Ti 5 o 12 The composite material was subjected to high-resolution TEM ( figure 2 ) and the Ramam test ( Figure 5 ), the results are shown in Li 4 Ti 5 ...

Embodiment 3

[0057] Example 3: Lithium cobalt oxide battery without low-temperature carbon coating

[0058] Follow Example 1 to prepare LiCoO 2 Battery, the battery is cycled at 2.5-4.5V, see the battery test results Figure 10 , The battery capacity decays quickly, and after 50 weeks, the capacity is only 80mAh / g.

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PUM

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Abstract

The invention provides a low-temperature carbon-coated composite material, its preparation method and application, and a secondary lithium battery containing the composite material. Specifically, the preparation method includes: leaving a carbon-containing precursor to react at a temperature of 200-600DEG C to generate a carbon material with high conductivity, and coating the surface of a used material evenly with the carbon material, thus obtaining the low-temperature carbon-coated composite material. The lithium secondary battery containing the composite material provided in the invention has the advantages of high reversible capacity, good circulation, outstanding rate performance, safety and reliability.

Description

technical field [0001] The invention relates to a low-temperature carbon-coated composite material, a preparation method and an application thereof, belonging to the field of materials. Background technique [0002] Lithium-ion batteries have been widely used in various portable devices, and have been used in electric vehicles and energy storage battery packs in small batches. The positive electrode materials used in commercially available batteries are mainly LiCoO 2 、LiFePO 4 , LiMn 2 o 4 etc., the negative electrode material is mainly graphite-like carbon material. These applications have higher and higher requirements on the performance of lithium-ion batteries, such as high energy density, high power density, rate performance, cycle stability, safety, etc. [0003] LiCoO 2 The theoretical capacity of the battery is 274mAh / g, and the actual specific capacity is between 130 and 150mAh / g; at most only about 0.55 lithium ions can be reversibly deintercalated, and a sma...

Claims

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Application Information

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IPC IPC(8): H01M4/62H01M10/0525
CPCY02E60/122Y02E60/10
Inventor 简泽浪赵亮汪锐胡勇胜李泓陈立泉
Owner INST OF PHYSICS - CHINESE ACAD OF SCI
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