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Lithium metal secondary battery negative electrode and preparation method thereof

A secondary battery and lithium metal technology, which is applied in the field of lithium metal secondary battery negative electrode and its modification, can solve the problems of low battery coulombic efficiency, lower battery energy density, lithium negative electrode volume expansion, etc., to improve coulombic efficiency, reduce Effect of volume expansion and inhibition of dendrite formation

Pending Publication Date: 2018-01-19
GREE ELECTRIC APPLIANCES INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, lithium metal as the negative electrode faces challenges in practical applications: dendrites will form on the surface of the lithium metal negative electrode during the charge-discharge cycle, and the growth of dendrites will pierce the separator, causing an internal short circuit in the battery, thereby causing safety issues. ;The formation of dendrites leads to unlimited expansion of the lithium negative electrode volume; at the same time, the dendrites may break and form "dead lithium", resulting in low coulombic efficiency of the battery, reducing the energy density of the battery, and seriously reducing the safety performance and cycle life of the battery

Method used

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  • Lithium metal secondary battery negative electrode and preparation method thereof
  • Lithium metal secondary battery negative electrode and preparation method thereof
  • Lithium metal secondary battery negative electrode and preparation method thereof

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preparation example Construction

[0056] The present invention also provides a preparation method of a lithium metal secondary battery negative electrode, comprising the following steps:

[0057] 1) After the graphene oxide aqueous solution is reduced by a hydrothermal method, a graphene hydrogel is obtained, and then after freeze-drying, a graphene foam is obtained;

[0058] 2) After the graphene foam obtained in the above steps is mixed with liquid metal lithium, the lithium metal secondary battery negative electrode is obtained.

[0059] In the invention, the graphene oxide aqueous solution is firstly reduced by a hydrothermal method to obtain a graphene hydrogel, and then freeze-dried to obtain a graphene foam.

[0060] The concentration of the graphene oxide aqueous solution is not particularly limited in the present invention, it can be purchased commercially or prepared according to a conventional method with a conventional concentration well known to those skilled in the art, and those skilled in the a...

Embodiment 1

[0090] 1. Prepare graphene oxide by modified Hummers method.

[0091] Add 500mg flake graphite into the mixed solution of sodium nitrate (500mg) and concentrated sulfuric acid (46ml), stir and control the temperature of the water bath to be less than 10°C, keep stirring and slowly add potassium permanganate (3g); after 30 minutes, transfer the reaction system to Put it in a water bath at 35°C, and keep stirring until the solution becomes colloidal; add 120ml of deionized water, then move the reaction system to a water bath at 95°C, stir for one hour, and add 5% H 2 o 2 Solution 15ml; wash with 1M dilute hydrochloric acid (500ml), and then fully wash with deionized water until the pH of the filtrate is greater than 5; after ultrasonic treatment for 1 hour, freeze-dry to obtain graphene oxide powder.

[0092] 2. Dissolve graphene oxide powder in water, conduct ultrasonic treatment for 2 hours, and prepare 4mg·ml -1 The graphene oxide solution is reduced by the hydrothermal met...

Embodiment 2

[0104] 1. Prepare graphene oxide by modified Hummers method.

[0105] Add 500mg flake graphite into the mixed solution of sodium nitrate (500mg) and concentrated sulfuric acid (46ml), stir and control the temperature of the water bath to be less than 10°C, keep stirring and slowly add potassium permanganate (3g); after 30 minutes, transfer the reaction system to Put it in a water bath at 35°C, and keep stirring until the solution becomes colloidal; add 120ml of deionized water, then move the reaction system to a water bath at 95°C, stir for one hour, and add 5% H 2 o 2 Solution 15ml; wash with 1M dilute hydrochloric acid (500ml), and then fully wash with deionized water until the pH of the filtrate is greater than 5; after ultrasonic treatment for 1 hour, freeze-dry to obtain graphene oxide powder.

[0106] 2. Dissolve graphene oxide powder in water, conduct ultrasonic treatment for 2 hours, and prepare 4mg·ml -1 The graphene oxide solution is reduced by the hydrothermal met...

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Abstract

The invention provides a lithium metal secondary battery negative electrode. The lithium metal secondary battery negative electrode comprises graphene foam and metal lithium compounded in the graphenefoam. The graphene foam is combined with the metal lithium, and the graphene foam is filled with the metal lithium; by taking the three-dimensional graphene foam as the framework, the liquid-state metal lithium can be automatically adsorbed in the three-dimensional graphene foam based on the lithium affinity property of the oxygen-containing functional group on the surface of reduced graphene oxide, while the three-dimensional graphene foam is formed by criss-cross flake graphene to form a porous structure, so that a relatively large specific surface area is formed, lithium can be well limited in the internal space, and volume expansion of a lithium negative electrode can be reduced; and meanwhile, the flake graphene also can influence the re-distribution of electric field in the battery,so that the lithium ion distribution on the surface of the electrode can be influenced, formation of dendritic crystal can be suppressed, improvement of the coulombic efficiency of the lithium negative electrode can be facilitated, and the obtained lithium metal negative electrode has relatively high flexibility.

Description

technical field [0001] The invention relates to the technical field of lithium secondary batteries, in particular to a negative electrode of a lithium metal secondary battery and a preparation method thereof, in particular to a negative electrode of a lithium metal secondary battery and a modification method thereof. Background technique [0002] Lithium-ion batteries have the advantages of high working voltage, high specific energy, long cycle life, light weight, less self-discharge, no memory effect and high cost performance, and have become rechargeable batteries in high-power electric vehicles, artificial satellites, aerospace and other fields The main selection object of the power supply. However, as people have higher requirements for battery capacity and long cycle life in electronic equipment, the performance of existing lithium-ion batteries is gradually unable to meet the application requirements. One of the key factors determining the performance of lithium-ion b...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M4/134H01M4/1395H01M10/052
CPCY02E60/10
Inventor 魏文飞蒋世用李乾乾段科王晋吉纯
Owner GREE ELECTRIC APPLIANCES INC
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