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Graphene/silicon lithium ion battery cathode material and preparation method thereof

A technology for lithium-ion batteries and negative electrode materials, applied in battery electrodes, circuits, electrical components, etc., to achieve high specific capacity, simple preparation process, and high cycle stability

Inactive Publication Date: 2010-12-22
UNIV OF SCI & TECH BEIJING +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The present invention adopts nano-silica powder and graphite oxide to disperse ultrasonically, directly suction filter or dry into a cake / film, and then roast in a reducing atmosphere to directly prepare a self-supporting graphene / silicon composite material, which is a lithium ion composite material with good performance. Battery negative electrode material, this kind of composite material preparation method for directly preparing self-supporting membrane has not yet been reported in literature and patents

Method used

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  • Graphene/silicon lithium ion battery cathode material and preparation method thereof
  • Graphene/silicon lithium ion battery cathode material and preparation method thereof
  • Graphene/silicon lithium ion battery cathode material and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0024] Example 1: Graphene / Silicon Composite Material I for Lithium-ion Battery Anode Material

[0025] Cool the concentrated sulfuric acid to 0°C, then add graphite and sodium nitrate, stir until uniform, gradually add potassium permanganate, stir for 3h, raise the temperature to 35°C, continue to stir for 0.5h, and then gradually add deionized With water, the temperature was raised to 98°C, reacted at this temperature for 15 minutes, moved to room temperature, added 5% hydrogen peroxide, stirred for 1 hour, then added 1M hydrochloric acid and mixed and stirred. The resulting product was washed with distilled water to neutrality to obtain graphite oxide. The graphite oxide is ultrasonically peeled off for 2 hours to obtain the graphene oxide material. The graphene oxide and silicon powder (~50nm) are mixed and ultrasonically dispersed at a mass ratio of 1:1 to uniformity, and then suction filtered into a cake. The filter cake is 95% Ar and 5% H 2 In a mixed atmosphere, the tempe...

Embodiment 2

[0026] Example 2: Graphene / silicon composite material II for lithium ion battery anode material

[0027] The graphene oxide material was prepared as described in Example 1. The graphene oxide and silicon powder (~50nm) were mixed and ultrasonically dispersed at a mass ratio of 5:1 to uniformity, and then suction filtered into a cake. The filter cake was heated to 90% Ar And 10% H 2 In a mixed atmosphere, the temperature was kept at 700° C. for 3 hours to obtain a graphene / silicon composite material II. The test conditions of the electrode material are as described in Example 1. When charging and discharging at a current density of 50 mA / g, the initial discharge capacity can reach 980 mAh / g, and the capacity after 30 cycles is still 930 mAh / g. When charging and discharging at a high current density of 500mA / g, its specific capacity is 760mAh / g after many cycles.

Embodiment 3

[0028] Example 3: Graphene / silicon composite material III for lithium ion battery anode material

[0029] The graphene oxide material was prepared as described in Example 1. The graphene oxide and silicon powder (~50nm) were mixed and ultrasonically dispersed at a mass ratio of 10:1 to uniformity, and then suction filtered into a cake. The filter cake was heated to 90% Ar And 10% H 2 In a mixed atmosphere, the temperature is kept at 700° C. for 3 hours to obtain the graphene / silicon composite material III. The test conditions of the electrode material are as described in Example 1. When charging and discharging at a current density of 50 mA / g, the initial discharge capacity can reach 880 mAh / g, and the capacity after 30 cycles is still 850 mAh / g. When charging and discharging at a high current density of 500mA / g, its specific capacity is 680mAh / g after many cycles.

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Abstract

The invention discloses a grapheme / silicon composite material for a lithium ion battery cathode material and a preparation method thereof, belonging to the fields of electrochemistry and new energy materials. The method comprises the following steps of: using graphite as a raw material; oxidizing the graphite into oxidized graphite by adopting oxidants of concentrated sulfuric acid and potassium permanganate; then, ultrasonically stripping the oxidized graphite to prepare oxidized graphene; mixing oxidized graphene in different proportions with nano silicon powder; ultrasonically dispersing, filtering or directly drying into a cake / film; and roasting under a reduction atmosphere to prepare self-support graphene / silicon composite film materials in different proportions. Proved by electrochemistry tests, the graphene / silicon composite film material prepared by the method has higher specific capacity and cycle stability, simple preparation method and easy mass production and consequently is an ideal high-energy lithium ion battery cathode material.

Description

Technical field [0001] The invention discloses a method for preparing graphene / silicon composite material, a negative electrode material for lithium ion batteries, and belongs to the fields of electrochemistry and new energy materials. Background technique [0002] Lithium-ion batteries have been widely researched and applied due to their advantages such as high operating voltage, large specific energy, long cycle life, no memory effect, small self-discharge, and no pollution to the environment. As a kind of energy storage battery, lithium-ion batteries have been widely used in mobile phones, laptops and solar / wind energy storage. At the same time, lithium-ion batteries are also used in electric vehicles and hybrid electric vehicles. The development of space technology and the development of national defense equipment Demand The demand for lithium-ion batteries is also growing rapidly. In short, the application prospects of lithium-ion batteries are very broad. [0003] At ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/139
CPCY02E60/122Y02E60/10
Inventor 范丽珍陶华超冯玉川陈立功
Owner UNIV OF SCI & TECH BEIJING
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