Inorganic doped/coated modification natural graphite, as well as preparation method and application thereof

A natural graphite and inorganic technology, applied in the field of inorganic doping/coating modified natural graphite, can solve the problems such as cycle performance can not meet market demand, high heat treatment graphitization temperature, difficult to achieve uniform coating, etc. The effect of improving high current charge and discharge performance, wide source of raw materials, and improving rate charge and discharge performance

Active Publication Date: 2014-08-06
SHANGHAI SECOND POLYTECHNIC UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] CN101246962A discloses a method of using ferrate liquid phase oxidation treatment of natural graphite, the preparation conditions of the method are mild, and remarkably improve the reversible capacity of modified graphite, but its cycle performance still can not meet the market demand
CN1417876A discloses a method of compounding a certain amount of metal oxide on the surface of graphite by a solution method, and obtaining a metal oxide-coated graphite negative electrode material and a preparation method thereof after drying. The preparation process of the method is simple, safe, and low in cost. The prepared graphite material has high specific capacity, but it needs to use acid-base solution to generate waste liquid, causing environmental pollution
CN102485648A discloses a method of using natural graphite to prepare modified graphite, the method reduces the specific surface area, improves the compacted density and the gram capacity, but its heat treatment graphitization temperature is high, the equipment requirements are high, and the energy consumption is large
Japanese patent JP10294111 uses pitch material to coat graphite carbon material at low temperature. After coating, non-melting treatment and light crushing are required. This method is difficult to achieve uniform coating.

Method used

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  • Inorganic doped/coated modification natural graphite, as well as preparation method and application thereof
  • Inorganic doped/coated modification natural graphite, as well as preparation method and application thereof
  • Inorganic doped/coated modification natural graphite, as well as preparation method and application thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0037] The modified natural graphite material for lithium-ion batteries in this example uses concentrated phosphoric acid and glacial acetic acid to react hydrothermally in a 100°C reactor for 10 hours, and then conducts a high-temperature treatment on the graphite obtained by the reaction, and simultaneously feeds nitrogen-containing organic matter, A nitrogen coating layer is formed on the graphite surface.

[0038] Take 12g of natural graphite and oxidize it with 1.2g of 85wt% concentrated phosphoric acid and 10ml of glacial acetic acid at 100°C for 10 hours. (Glacial acetic acid is used as an oxidizing acid, and concentrated phosphoric acid is used as both a dopant and an oxidizing acid).

[0039] After cooling naturally, the samples were dried in an oven.

[0040] The dried sample was put into a tube furnace with nitrogen, and 30ml of diethylamine was introduced at the same time, the temperature was raised to 1000°C at 16°C / min, kept for 2 hours, and naturally cooled to ...

Embodiment 2

[0046] In this example, the amount of phosphoric acid added was 2.4 g, the hydrothermal reaction was carried out at 90° C. for 12 hours, and the high temperature treatment holding time was 12 hours. Other processes and conditions were consistent with those in Example 1. The average particle diameter D of the modified graphite obtained in the present embodiment 50 -Basically consistent with Example 1. The discharge current density in the first cycle of 0.1C charge and discharge is 36mA / g, the first charge gram capacity is 406.1mAh / g, the first discharge gram capacity is 462.2mAh / g, and the first coulombic efficiency is 87.9%. At a current density of 5C, the charging capacity is 324.8 mAh / g, and the capacity retention rate is 80.0%.

Embodiment 3

[0048] In this embodiment, glacial acetic acid is used as the oxidizing acid, and the dopant added is red phosphorus in an amount of 2.4 g, and the hydrothermal reaction is carried out at 180° C. for 0.5 hours. Other than that, other processes and conditions were consistent with Example 1. The average particle diameter D of the modified graphite obtained in the present embodiment 50 -Basically consistent with Example 1. The discharge current density in the first cycle of 0.1C charge and discharge is 36mA / g, the first charge gram capacity is 335.6mAh / g, the first discharge gram capacity is 378.0mAh / g, and the first coulombic efficiency is 88.8%. At a current density of 5C, the charging capacity is 285.3mAh / g, and the capacity retention rate is 85.0%.

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Abstract

The invention belongs to the technical field of energy materials and electrochemistry and in particular relates to inorganic doped/coated modification natural graphite, as well as a preparation method and application of the inorganic doped/coated modification natural graphite. The preparation method comprises the following steps: adding natural graphite, oxidizing acid and inorganic doped raw materials in a reaction kettle to carry out hydrothermal reaction for 0.5-12 hours at the reaction temperature of 90-180 DEG C and thus obtaining a product which is expanded graphite A; drying the expanded graphite A in a drying box to obtain dried and expanded graphite B; treating the expanded graphite B at the high temperature of 600-1600 DEG C under the protective atmosphere, simultaneously introducing nitrogenous organic compounds to form a nitrogen coated layer on the surface of the expanded graphite B, finally obtaining modified natural graphite. The preparation method is simple in process, easy to control, wide in sources of raw materials and low in cost. The prepared materials is excellent in repeatability, has the advantages of doping and coating modification, is excellent in material property and can be used as the negative electrode material of the lithium battery.

Description

technical field [0001] The invention belongs to the technical field of energy materials and electrochemistry, and specifically relates to an inorganic doping / coating modified natural graphite, a preparation method and an application thereof. Background technique [0002] Since Japan's Sony Corporation successfully used carbon materials to make lithium-ion battery negative electrode materials in 1991, lithium-ion battery negative electrode carbon materials have received extensive attention. Moreover, lithium-ion batteries rapidly occupy the civilian secondary battery market at an average annual rate of 15%. In recent years, lithium-ion batteries have been widely used in electronic products such as mobile phones, portable notebook computers, digital video cameras, digital cameras, and tablet computers. Lithium-ion batteries have excellent performances such as high energy density, high working voltage, small size, light weight, no pollution, good safety, and long life. They ar...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/583
CPCH01M4/583H01M10/0525Y02E60/10
Inventor 王利军刘华靖
Owner SHANGHAI SECOND POLYTECHNIC UNIVERSITY
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