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Silicon-carbon composite electrode and preparation method thereof

A silicon-carbon composite and electrode technology, applied in battery electrodes, circuits, electrical components, etc., can solve problems such as rate performance affecting material cycle performance, poor bonding force between silicon and carbon materials, poor consistency, etc., to improve the first efficiency and process. The effect of controllable and good solubility

Inactive Publication Date: 2017-11-28
深圳市金牌新能源科技有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The preparation process is mainly prepared by the solid phase method, and there are defects such as poor consistency, poor bonding force between silicon and carbon materials in the material, and poor conductivity, which affect the cycle performance and rate performance of the material.

Method used

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  • Silicon-carbon composite electrode and preparation method thereof
  • Silicon-carbon composite electrode and preparation method thereof
  • Silicon-carbon composite electrode and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] A silicon-carbon composite electrode has a core-shell structure, in which the inner core includes silicon powder and hollow carbon spheres doped in the silicon powder, and an inorganic lithium salt compound electrodeposited between the silicon powder and the hollow carbon spheres, and the outer shell is a polymer polymer.

[0023] Optimally, the inorganic lithium salt compound is one of lithium carbonate, lithium hydroxide, lithium metaaluminate, and lithium borate, and lithium carbonate is preferred in this embodiment.

[0024] Optimally, the silicon powder is 50-500nm nano-silicon, and the silicon powder can be 50nm nano-silicon, 200nm nano-silicon or 500nm nano-silicon, etc. In this embodiment, it is preferably 50nm nano-silicon.

Embodiment 2

[0026] 1) In an environment with a dew point ≤ -30°C, weigh 10g of silicon powder with a particle size of 100nm, 10g of sodium dodecylbenzenesulfonate, and 10g of hollow carbon spheres and add them to 500ml of toluene solvent for reaction, dry and pulverize to obtain a precursor Body, then mixed with 1g of polyvinylidene fluoride binder and pressed onto the nickel foam to obtain electrode A;

[0027] 2) Add 2g of lithium carbonate to 100ml of ethylene carbonate to dissolve, stir evenly to obtain a solvent, then use electrode A as the working electrode, platinum sheet as the counter electrode, and use cyclic voltammetry (voltage range -3V ~ 3V, scan speed 2mV / S, scanning for 10 weeks), deposit lithium salt on the surface of the working electrode, then take it out and clean it with pure ethylene carbonate, and dry it to obtain a lithium-silicon composite electrode;

[0028] 3) Add 20 g of lithium-supplemented silicon composite electrode to 150 ml of polypropylene carbonate solve...

Embodiment 3

[0030] 1) In an environment with a dew point ≤ -30°C, weigh 5g of silicon powder with a particle size of 50nm, 5g of sodium dodecylbenzenesulfonate, and 5g of hollow carbon spheres and add them to 500ml of carbon tetrachloride solvent for reaction, dry and pulverize Finally, the precursor is obtained, and then mixed with 0.5g of polyvinylidene fluoride binder and pressed onto the nickel foam to obtain electrode A;

[0031] 2) Afterwards, add 0.5g lithium hydroxide to 100ml ethylene carbonate to dissolve and stir evenly to obtain a solvent, then use electrode A as the working electrode, platinum sheet as the counter electrode, and use cyclic voltammetry (voltage range -3V-3V , scanning speed is 0.5mV / s, scanning 10 weeks), lithium salt is deposited on the surface of the working electrode, then taken out and cleaned with pure ethylene carbonate, dried to obtain lithium-silicon composite material;

[0032] 3) Afterwards, 5 g of the lithium-supplementing silicon composite material...

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Abstract

The invention discloses a silicon-carbon composite electrode and a preparation method thereof. The silicon-carbon composite electrode is of a shell-core structure, wherein a core contains silicon powder, a hollow carbon sphere and an inorganic lithium salt compound, the hollow carbon sphere is doped into the silicon powder, and the inorganic lithium salt compound is electrically deposited between the silicon powder and the hollow carbon sphere; and a shell is a high-molecular polymer. According to the silicon-carbon composite electrode prepared by virtue of the preparation method, by utilizing lithium salt deposited on the surface of silicon, the lithium ion transmission rate during charging and discharging is increased, sufficient lithium ions are provided for the formation of an SEI membrane, the initial efficiency can be obviously improved, the expansion rate of a silicon material can be decreased, and the cycle performance of the silicon material can be improved; and meanwhile, the silicon-carbon composite electrode has the characteristics of high stability and strong stability at 100-150 DEG C, the contact between the lithium salt material and air can be avoided, and the processability and the safety performance of the lithium salt material can be improved; and furthermore, the polymer has relatively good dissolving property with an electrolyte solvent, so that the polymer can serve as lithium salt, and the initial efficiency, safety performance and energy density of a cathode material are improved.

Description

technical field [0001] The invention relates to the field of lithium-ion battery preparation materials, in particular to a silicon-carbon composite electrode and a preparation method thereof. Background technique [0002] At present, commercial lithium-ion batteries generally use graphite-like carbon materials as negative electrode materials. Due to the low theoretical electrochemical capacity of the electrode itself (theoretical capacity 372mAh / g), it is difficult to meet the needs of high specific capacity lithium-ion batteries. The silicon-carbon anode material is a new type of energy storage anode material developed in recent years. Silicon has a theoretical electrochemical capacity (theoretical capacity 4200mAh / g) that is 10 times higher than that of widely used carbon materials at present, and a low lithium intercalation capacity. Voltage (less than 0.5V), there is no co-intercalation of solvent molecules during the intercalation process, and it is abundant in the eart...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/587H01M4/62H01M10/0525
CPCH01M4/366H01M4/386H01M4/587H01M4/628H01M10/0525Y02E60/10
Inventor 梁慧宇
Owner 深圳市金牌新能源科技有限责任公司
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