Preparation method and uses of starch-based composite hard carbon negative electrode material

A negative electrode material, starch-based technology, applied in the field of preparation of starch-based composite hard carbon negative electrode materials, can solve the problems of low efficiency restricting industrial application, graphite layer peeling and pulverization, SEI film instability and other problems, and achieve high current charging Good discharge performance, low cost, common source of raw materials

Inactive Publication Date: 2017-12-01
NINGBO SHANSHAN NEW MATERIAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the current graphite negative electrode has the following problems: 1. The potential platform is close to the potential of metal lithium, and it is easy to precipitate dendrite Li and cause a short circuit; 2. The SEI film is unstable and prone to Li + Co-embedded graphite layer with organic solvent, resulting in graphite exfoliation and pulverization; 3. Graphite C interlayer spacing (d 002 ≤0.34nm)x C 6 (~0.37nm), the volume change is 8%, which will easily lead to the peeling and pulverization of the graphite layer; 4. The exothermic reaction between graphite and organic solvents will easily produce flammable gases, and the battery is easy to burn; 5. Li + Small diffusion coefficient, difficult to charge quickly
Hard carbon can be divided into two types according to the source of biomass and fossil resources. The use of biomass starch as a hard carbon precursor has the advantages of environmental protection and low cost, but its low initial efficiency restricts its industrial application.

Method used

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  • Preparation method and uses of starch-based composite hard carbon negative electrode material
  • Preparation method and uses of starch-based composite hard carbon negative electrode material

Examples

Experimental program
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Effect test

Embodiment 1

[0020] The starch was first kept at a constant temperature of 170°C for 48 hours in an air atmosphere until the starch completely turned into a black powder, then raised to 900°C at a rate of 2°C / min under a nitrogen atmosphere, kept for 4 hours, and then naturally cooled to room temperature to obtain starch-based hard carbon .

[0021] Mix starch-based hard carbon with sucrose and flaky graphite with a D50 of 1 μm in a weight ratio of 20:3:0.1 to obtain a raw material mixture, and add the raw material mixture to twice its volume of deionized water, stir or sonicate for 1 hour , and dried at 80°C until it became a solid powder to obtain a carbon precursor.

[0022] Put the carbon precursor into the furnace, and carbonize at a high temperature of 700°C for 1 hour under a nitrogen atmosphere to obtain composite carbonized particles.

[0023] After the carbonized particles are sieved through 60 meshes, the under-sieves are taken, and classified in a classifier at a frequency of ...

Embodiment 2

[0026] The starch was first kept at a constant temperature of 250°C for 24 hours in an air atmosphere until the starch completely turned into a black powder, then raised to 1100°C at a rate of 2°C / min under a nitrogen atmosphere, kept for 1 hour, and then naturally cooled to room temperature to obtain starch-based hard carbon .

[0027] Mix starch-based hard carbon with sucrose and flake graphite with a D50 of 5 μm in a weight ratio of 20:3:3 to obtain a raw material mixture, and add the raw material mixture to twice its volume of deionized water for stirring or ultrasonication for 1 h, Dry at 80°C until it becomes a solid powder to obtain a carbon precursor.

[0028] Put the carbon precursor into the furnace, and carbonize at a high temperature of 850° C. for 4 hours under a nitrogen atmosphere to obtain composite carbonized particles.

[0029] After the carbonized particles are sieved through 200 meshes, the undersieves are taken and classified in a classifier at a frequenc...

Embodiment 3

[0032] The starch was first kept at a constant temperature of 200°C for 36 hours in an air atmosphere until the starch completely turned into a black powder, then raised to 1000°C at a rate of 2°C / min under a nitrogen atmosphere, kept for 2 hours, and then naturally cooled to room temperature to obtain starch-based hard carbon .

[0033] Mix starch-based hard carbon with sucrose and flake graphite with a D50 of 3 μm in a weight ratio of 20:3:1 to obtain a raw material mixture, and add the raw material mixture to twice its volume of deionized water for stirring or ultrasonication for 1 h, Dry at 80°C until it becomes a solid powder to obtain a carbon precursor.

[0034] Put the carbon precursor in the furnace, and carbonize at a high temperature of 800°C for 2 hours under a nitrogen atmosphere to obtain composite carbonized particles.

[0035] After the carbonized particles are sieved through 150 meshes, the undersieve is taken, and classified in a classifier at a frequency of...

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Abstract

The invention relates to the technical field of lithium ion battery materials, particularly to a preparation method and uses of a starch-based composite hard carbon negative electrode material. The preparation steps comprise: (1) carrying out two-step carbonizing to obtain starch-based hard carbon; (2) preparing a carbon precursor through a liquid-phase immersion method; (3) carrying out high-temperature carbonization; and (4) screening, and grading. Compared to the method in the prior art, the method of the present invention has the following advantages that the raw material source is common, the cost is low, no organic solvent is used, toxic and harmful waste residue and tail gas are not generated, the preparation process is environmentally friendly and pollution-free, and the prepared material has the first discharge capacity of more than 450 mAh / g and the first charge and discharge efficiency of more than 80%, has advantages of good electrochemical performance, good cycle performance, good charge and discharge performance at high current, good safety, good adaptability to electrolytes and other additives and stable property, wherein the difference between batches almost does not exist.

Description

technical field [0001] The invention relates to the technical field of lithium ion battery materials, in particular to a preparation method and application of a starch-based composite hard carbon negative electrode material. Background technique [0002] Lithium-ion battery is a new type of high-energy secondary battery that began to be put into practical use in the 1990s. It has the advantages of high working voltage, light weight, large specific energy, small self-discharge, long cycle life, no memory effect and low environmental pollution. Lithium-ion battery anode materials are mainly carbon, mainly artificial graphite, natural graphite and amorphous carbon. However, the current graphite negative electrode has the following problems: 1. The potential platform is close to the potential of metal lithium, and it is easy to precipitate dendrite Li and cause a short circuit; 2. The SEI film is unstable and prone to Li + Co-embedded graphite layer with organic solvent, result...

Claims

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Application Information

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IPC IPC(8): H01M10/0525H01M4/583H01M4/1393
CPCH01M4/1393H01M4/362H01M4/583H01M10/0525Y02E60/10
Inventor 王磊乔永民苏蒙谢秋生王建明刘萍吴志红丁晓阳杜辉玉
Owner NINGBO SHANSHAN NEW MATERIAL TECH
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