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Lithium metal surface modification method and lithium metal battery

A lithium metal and lithium battery technology, applied in the field of material chemistry, can solve the problems of uneven deposition and lack of lithium metal, and achieve the effect of improving long-term cycle performance, avoiding the formation of growth, and achieving good and uniform deposition.

Inactive Publication Date: 2021-05-11
NINGBO UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] On the second aspect, there will inevitably be scratches on the surface of the original lithium metal, and a passivation layer with different thicknesses and unknown components, which makes lithium metal as the negative electrode, and lithium metal deposition is uneven during the cycle. , obviously it is necessary to pre-treat the surface of the original lithium metal
However, these existing studies did not start from the essential source of lithium metal corrosion, but only used simple chemical or electrochemical means to perform surface polishing to obtain a relatively smooth surface of lithium metal, lacking the application of lithium metal in lithium batteries. A more precise grasp of corrosion phenomena

Method used

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  • Lithium metal surface modification method and lithium metal battery
  • Lithium metal surface modification method and lithium metal battery
  • Lithium metal surface modification method and lithium metal battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] A method for modifying lithium metal surfaces, comprising the steps of:

[0025] 1) Prepare electrolyte for lithium battery;

[0026] 2) Use the electrolyte in step 1) for a two-electrode system to measure the polarization curve of lithium metal in the electrolyte, and obtain the voltage parameters of the optimal passivation region of lithium metal according to the polarization curve;

[0027] 3) Assemble a lithium metal symmetric battery, use lithium metal as the positive and negative electrodes, and add the electrolyte prepared in step 1) to wet the diaphragm, seal the assembled lithium metal symmetric battery, and then use the voltage parameters obtained in step 2) The constant potential charge treatment is carried out on the lithium metal symmetric battery to obtain the lithium metal after surface modification.

[0028] In this example, the preparation of the lithium battery electrolyte in step 1) specifically includes: weighing a certain amount of lithium bromide ...

Embodiment 2

[0033] Weigh 1 mmol (0.0868 g) lithium bromide (LiBr) and 20 mmol (1.3788 g) lithium nitrate (LiNO3 ) into 20 mL of tetraethylene glycol dimethyl ether (TEGDME), then sealed and stirred for 2 h to obtain a clear electrolyte.

[0034] Then the prepared electrolyte solution was added to a 50mL double-hole sealed electrolytic cell. The working electrode used a lithium sheet (d=15.6 mm), the auxiliary electrode and the reference electrode were made of stainless steel sheets, and the LSV ( Linear Sweep Voltammetry, linear sweep voltammetry) program to measure the polarization curve of lithium metal in the above electrolyte, the test parameters are set as: Init E (initial potential, V) = open circuit voltage, Final E (end potential, V) = 0.1, ScanRate (scanning speed, V / s)=0.005, Sample Interval (sampling interval, V)=0.001, Quiet Time (quiet time, sec)=2, Sensitivity (sensitivity, A / V)=1.0×10 -3 , to obtain the polarization curve of lithium metal in the electrolyte.

[0035] Use t...

Embodiment 3

[0037] Weigh 1.6 mmol (0.1388 g) lithium bromide (LiBr) and 20 mmol (1.3788 g) lithium nitrate (LiNO 3 ) into 20 mL of tetraethylene glycol dimethyl ether (TEGDME), then sealed and stirred for 2 h to obtain a clear electrolyte.

[0038] Then the prepared electrolyte solution was added to a 50mL double-hole sealed electrolytic cell. The working electrode used a lithium sheet (d=15.6 mm), the auxiliary electrode and the reference electrode were made of stainless steel sheets, and the LSV ( Linear Sweep Voltammetry, linear sweep voltammetry) program to measure the polarization curve of lithium metal in the above electrolyte, the test parameters are set as: Init E (initial potential, V) = open circuit voltage, Final E (end potential, V) = 0.1, ScanRate (scanning speed, V / s)=0.005, Sample Interval (sampling interval, V)=0.001, Quiet Time (quiet time, sec)=2, Sensitivity (sensitivity, A / V)=1.0×10 -3 , the polarization curve of lithium metal in the electrolyte is obtained as figure...

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Abstract

The invention discloses a lithium metal surface modification method. The method is characterized by comprising the following steps: 1) preparing an electrolyte of a lithium battery; (2) measuring a polarization curve of the lithium metal in the electrolyte by using the electrolyte in step (1) in a two-electrode system, and obtaining a voltage parameter of an optimal passivation region of the lithium metal according to the polarization curve; and (3) assembling the lithium metal symmetric battery, taking the lithium metal as a positive electrode and a negative electrode, adding the electrolyte prepared in the step (1) to wet a diaphragm, sealing the assembled lithium metal symmetric battery, and then performing constant-potential charging treatment on the lithium metal symmetric battery by using the voltage parameters obtained in step (2) to obtain a surface-modified lithium metal. The method has the advantages that the surface of the lithium metal is treated by measuring the polarization curve of the lithium metal in the electrolyte to obtain the parameters of the optimal passivation region, so that the problem of surface passivation is essentially solved, the lithium metal with a smooth metallographic phase is obtained, and the long-acting cycle performance of the lithium metal battery is further improved.

Description

technical field [0001] The invention relates to the field of material chemistry, in particular to a method for modifying the surface of lithium metal and a lithium metal battery. Background technique [0002] The energy density of lithium-ion batteries currently on the market is around 300 Wh / kg (±20 Wh / kg). If you want to break through 350 Wh / kg or even 500 Wh / kg in the future, you can only rely on the next generation of high-energy batteries. The next generation of high-energy batteries mainly include: Li-O 2 (3500 Wh / kg) and Li-S (2600 Wh / kg), etc. Among them, lithium metal is mainly used as the negative electrode to increase the capacity of the battery, because lithium metal has a high theoretical specific capacity (3860 mAh g -1 ), and because of its lowest redox potential (-3.04 V vs standard hydrogen electrode), lithium metal batteries have a higher operating voltage (Jun Liu et al, NatureEnergy, 2019, 4(3):180-186). [0003] However, there are many problems in the ...

Claims

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Application Information

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IPC IPC(8): H01M4/1395H01M4/04H01M10/052
CPCH01M4/0438H01M4/1395H01M10/052Y02E60/10
Inventor 辛星时开元
Owner NINGBO UNIV
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