Graphene quantum dot modified electrolyte and preparation method thereof

A technology of graphene quantum dots and electrolytes, applied in organic electrolytes, non-aqueous electrolytes, circuits, etc., can solve problems such as inability to meet the protection requirements of high-performance lithium metal batteries, unfavorable scale and commercialization, and complex processes. Achieve the effects of eliminating hidden dangers of short circuit, inhibiting dendrite growth, and simple preparation process

Active Publication Date: 2019-11-26
UNIV OF ELECTRONIC SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, existing technical solutions, such as Kim et al. (Kim, et al. Controlled Lithium Dendrite Growth by a Synergistic Effect of Multilayered Graphene Coating and an Electrolyte Additive. Chem. Ma ter. 2015, 27 (8), 2780-2787.), Zhang .R et al (Zhang.R, etal.Conductive Nanostructured Scaffolds Render Low Local Current Density toInhibit Lithium Dendrite Growth.Adv.Mater.2016,28(11),2155-62.) and Zheng.G et al (Zheng. G, etal.Interconnected hollow carbon nano spheres for stable lithiummetal anodes.Nat.Nanotech.2014,9(8),618-623.), are limited to small current (≤2mA/cm 2 ) and low capacity (≤2mAh/cm 2 Li dendrite inhibition study under )
As the load and rate of the positive electrode of lithium metal batteries (such as Li-S batteries) continue to increase, the lithium metal negativ

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  • Graphene quantum dot modified electrolyte and preparation method thereof
  • Graphene quantum dot modified electrolyte and preparation method thereof
  • Graphene quantum dot modified electrolyte and preparation method thereof

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[0030] Example 1

[0031] A method for preparing graphene quantum dot modified electrolyte includes the following steps:

[0032] Step 1: Mix 50ml of DOL and 50ml of 1,2-dimethoxyethane to obtain an organic solvent, and then add 0.1 mol of LiTFSI salt to the organic solvent to obtain a mixed solution A;

[0033] Step 2: Add 50 mg of graphene quantum dots to the mixed solution A obtained in step 1, and stir for 24 hours to obtain dispersion B;

[0034] Step 3: Add 5 g of polyethylene oxide to the dispersion B, and stir for 24 hours to obtain the modified electrolyte.

[0035] Battery assembly and testing: Lithium symmetrical batteries are assembled using conventional assembly processes in the field, including positive electrodes, negative electrodes, separators, and the above-mentioned modified electrolyte. The positive and negative electrodes are both lithium metal sheets.

[0036] The battery test is constant current charge and discharge, the current is set to 3mA / cm 2 , The single cycl...

Example Embodiment

[0037] Example 2

[0038] The electrolytic solution modified by graphene quantum dots was prepared according to the steps of Example 1, and only the amount of graphene quantum dots added in step 2 was adjusted to 100 mg.

[0039] The constant current charge and discharge curve of the lithium metal symmetric battery obtained in this embodiment is as follows image 3 Shown.

Example Embodiment

[0040] Example 3

[0041] The electrolytic solution modified by graphene quantum dots was prepared according to the steps of Example 1, and only the amount of graphene quantum dots added in step 2 was adjusted to 150 mg.

[0042] The lithium metal symmetrical battery obtained in this example was subjected to a constant current charge and discharge test, and the current was set to 3mA / cm 2 , The single cycle capacity is set to 4mAh / cm 2 , Its constant current charge and discharge curve is like Figure 4 Shown.

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Abstract

The invention provides a graphene quantum dot modified electrolyte and a preparation method thereof, and belongs to the field of lithium metal battery electrolytes. By adding graphene quantum dots anda polymer in the commercial electrolyte, the graphene quantum dots can continuously provide nucleation sites, and the polymer enables uniform dispersion of the graphene quantum dots in the electrolyte, thereby obtaining simple process and obviously improving cycling and multiplying performance of lithium metal batteries under operating conditions of high current and high capacity. When the lithium metal batteries in the graphene quantum dot modified electrolyte have a current density reaching 4mA/cm2 and a cycling capacity reaching 4mAh/cm2, there is still no short circuit caused by lithium dendrites, and good charging and discharging performance is kept, thereby having potential application in the field of lithium metal batteries, and realizing the purpose of lithium negative protectionunder high current and high capacity.

Description

technical field [0001] The invention belongs to the field of electrolytes for lithium metal batteries, and in particular relates to an electrolyte modified with graphene quantum dots and a preparation method thereof. Background technique [0002] With the rapid development of fields such as portable electronic devices and electric vehicles, society's demand for high-energy-density energy storage batteries has shown explosive growth. Metal lithium electrodes have a theoretical capacity (3860mAh / g) ten times that of carbon-based lithium-ion electrodes, and the resulting lithium metal batteries, such as lithium-sulfur batteries (Li-S) and lithium-oxygen batteries (Li-O 2 ), considered to be the most promising energy storage device with high energy density. However, lithium metal electrodes will generate a large number of dendrites during the charging and discharging process, which not only affects the cycle performance, but also punctures the separator, short-circuits the batt...

Claims

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Application Information

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IPC IPC(8): H01M10/0567H01M10/0525H01M10/42
CPCH01M10/0525H01M10/0567H01M10/4235H01M2300/0025Y02E60/10
Inventor 熊杰胡音陈伟雷天宇李政翰王显福晏超贻黄建文
Owner UNIV OF ELECTRONIC SCI & TECH OF CHINA
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