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Preparation method of composite lithium metal negative electrode with three-dimensional structure and product thereof

A three-dimensional structure, metal negative electrode technology, applied in structural parts, battery electrodes, electrode carriers/collectors, etc., can solve Coulombic efficiency and battery capacity decay, hinder the practical application of lithium metal batteries, and unstable solid electrolyte membranes. Achieve the effects of inhibiting dendrite growth, reducing nucleation overpotential, and improving lithium-friendly performance

Pending Publication Date: 2022-04-05
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, metal lithium directly used as the negative electrode material of lithium metal batteries has infinite volume expansion during cycling, which can easily cause electrode pulverization and failure.
At the same time, lithium metal has strong reducibility, and can react with almost all organic electrolytes to form an unstable solid electrolyte membrane (SEI). reaction, resulting in the decay of Coulombic efficiency and battery capacity
Worse, the uneven Li deposition produces dendrite-like Li growth, and the Li dendrites may pierce the separator causing an explosion or even a fire.
These problems have seriously hindered the practical application of lithium metal batteries

Method used

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  • Preparation method of composite lithium metal negative electrode with three-dimensional structure and product thereof
  • Preparation method of composite lithium metal negative electrode with three-dimensional structure and product thereof
  • Preparation method of composite lithium metal negative electrode with three-dimensional structure and product thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The carbon fiber cloth was soaked in concentrated nitric acid (mass fraction is about 68%) and heated in a gradient. The gradient temperature was 80°C, 90°C, 100°C and 120°C; the modification treatment time was 2h, 20min, 30min and 30min. Then it was washed with deionized water and ethanol to obtain a modified carbon fiber cloth. Get 0.3g of cobalt nitrate hexahydrate (Co(NO 3 ) 2 ·6H 2 O) and 2.5ml of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF 4 ) in 25ml of ethanol solution, electromagnetically stirred until the solution is uniform, then transferred to a 50ml hydrothermal reaction kettle after ultrasonic treatment for 30 minutes, placed the modified carbon fiber in the hydrothermal reaction kettle into the reaction solution, and sealed the reaction Put it into an oven for solvothermal reaction, keep it at 150°C for 6h, take it out, wash it with water and ethanol several times, put it in an oven at 60°C, and dry it for 12h to obtain a carbon fiber cloth...

Embodiment 2

[0035] Embodiment 2 performance test

[0036] 1) Performance test of the prepared symmetrical battery

[0037] The composite negative electrode (CoF) of three-dimensional structure in embodiment 1 2 -CC@Li) was placed on both sides of the separator to form a symmetrical battery; in Comparative Examples 1 and 2, Cu@Li and CC@Li were placed on both sides of the separator to form a symmetrical battery. The electrolyte is 1M LiTFSI+DOL:DME(1:1,v / v)+2wt%LiNO 3 .

[0038] The symmetrical battery that embodiment 1 and comparative example 1 and 2 are formed is in 2mA cm -2 and 1mAh cm -2 Under the condition of , its time-voltage curve is as follows Figure 5 , it can be seen that the symmetrical battery with the composite negative electrode of the three-dimensional structure can maintain a relatively small polarization voltage stable cycle of 3600h.

[0039] The symmetrical battery that embodiment 1 and comparative example 1 and 2 are formed is in 3mA cm -2 and 1mAh cm -2 Unde...

Embodiment 3

[0045] The carbon fiber cloth was soaked in hydrogen peroxide solution (30% by mass) and heated at 80° C. for 12 h, and then washed with deionized water and ethanol to obtain a modified carbon fiber cloth. Get 0.3g of cobalt chloride hexahydrate (Co(NO 3 ) 2 ·6H 2 O) and 0.5 g of ammonium fluoride (NH 4 F) Mix in 25ml of methanol solution, stir electromagnetically until the solution is uniform, transfer it to a 50ml hydrothermal reaction kettle after ultrasonic treatment for 30 minutes, place the modified carbon fiber in the hydrothermal reaction kettle into the reaction solution, and seal Reactor, put it in an oven for solvothermal reaction, keep it at 120°C for 8 hours, take it out, wash it with water and ethanol several times, then put it in an oven at 40°C and dry it for 24 hours to obtain a carbon fiber cloth uniformly coated with cobalt fluoride (CoF 2 -CC).

[0046] In a glove box filled with argon, commercial lithium metal foil (diameter 15.6 mm, thickness 1.5 mm)...

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Abstract

The invention discloses a preparation method of a composite lithium metal negative electrode with a three-dimensional structure and a product of the composite lithium metal negative electrode. An inherent pore structure of carbon fiber cloth taking thin-crystal graphite flakes as pore walls not only can relieve volume change in a lithium deposition / dissolution process, but also can introduce a lithium storage mechanism through a lithium insertion / extraction path; and meanwhile, the carbon cloth has light weight and good flexible mechanical properties, and can inhibit the growth of lithium dendrites. In the lithium electrochemical deposition process, the metal lithium and the cobalt fluoride are subjected to an irreversible reduction reaction to form cobalt nanoparticles and the lithium fluoride; the cobalt nanoparticles have smaller binding energy with the lithium metal, so that nucleation sites can be increased, the nucleation overpotential of the lithium metal is reduced, and uniform diffusion of lithium ions is promoted. The lithium fluoride formed in situ has good interface contact with the carbon fiber cloth, has high mechanical modulus, high chemical stability and high interface energy with lithium, and can uniformize lithium ion flux and effectively inhibit dendritic crystal growth of lithium.

Description

technical field [0001] The invention belongs to the technical field of negative electrodes of lithium metal batteries, and in particular relates to a preparation method of a three-dimensional structure composite lithium metal negative electrode and a product thereof. Background technique [0002] The rapid development of portable electronics and electric vehicles requires electrochemical energy storage devices with higher volumetric and mass energy densities. Lithium metal has a relatively high theoretical specific capacity (3860mAh g -1 ), the smallest electrochemical potential (-3.04V, compared with the standard hydrogen electrode), small bulk density (0.534gcm -3 ), is the most promising anode material for next-generation energy storage materials. However, metal lithium directly used as the anode material of lithium metal batteries has infinite volume expansion during cycling, which easily causes electrode pulverization and failure. At the same time, lithium metal has ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1395H01M4/38H01M4/62H01M4/66H01M4/134H01M10/0525B82Y30/00
CPCY02E60/10
Inventor 潘安强冯明阳周双
Owner CENT SOUTH UNIV
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