Lithium metal battery electrolyte accommodating aromatic compound as diluent

A technology of lithium metal batteries and compounds, which is applied in the direction of lithium batteries, secondary batteries, organic electrolytes, etc., can solve the problems of reduced cycle performance and high cost of electrolytes, etc., to prolong cycle life, inhibit the growth of dendrites, The effect of high conductivity

Active Publication Date: 2020-03-17
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The invention solves the lithium dendrite phenomenon caused by the uneven deposition of the lithium metal negative electrode in the cycle process, and the phenomenon that the dead lithium generated by the reaction of the lithium metal negative electrode and the electrolyte reduces the cycle performance, especially the high cost of the conventional electrolyte The problem

Method used

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  • Lithium metal battery electrolyte accommodating aromatic compound as diluent
  • Lithium metal battery electrolyte accommodating aromatic compound as diluent
  • Lithium metal battery electrolyte accommodating aromatic compound as diluent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Lithium bisfluorosulfonyl imide, dimethyl carbonate, and toluene were made into a homogeneous solution at a molar ratio of 1:10:0, 1:2:0, and 1:2:4 respectively (control group 1, control group 2 and experimental group), using the above electrolyte, lithium sheets, copper sheets, and separators to assemble a lithium-copper half-cell, and at 1mAcm -2 The Coulombic efficiency test is carried out under the current density, such as figure 1 As shown, in the experimental group of the electrolyte with toluene added as a diluent, the battery test was stable for more than 100 cycles, and the average Coulombic efficiency was higher than 99.3%, while the control group could not be stabilized.

Embodiment 2

[0035] The lithium salt used is lithium hexafluorophosphate, and the rest are the same as in Example 1.

Embodiment 3

[0037] Prepare lithium bisfluorosulfonyl imide, ethylene glycol dimethyl ether, and fluorobenzene at a molar ratio of 1:2:0, 1:2:2, 1:2:4, and 1:2:6 to form a homogeneous solution (Sequentially ratio 1, ratio 2, ratio 3 and ratio 4), use above-mentioned electrolytic solution and lithium sheet, copper sheet, diaphragm to be assembled into lithium-copper half cell together, and in 3mAcm -2 The Coulombic efficiency test is carried out under the current density, such as figure 2 As shown, in the ratio 3 experimental group in which benzene was added as a diluent and the ratio of the electrolyte was 1:2:4, the battery test was stable for more than 250 cycles, and the average Coulombic efficiency was higher than 99.4%, while the other ratios of the electrolyte All exhibit low Coulombic efficiency and short cycle life.

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Abstract

The invention relates to a lithium metal battery electrolyte accommodating aromatic compounds as diluents, and belongs to the technical field of lithium metal batteries. The electrolyte contains a lithium salt, a solvent for dissolving the lithium salt and a diluent, wherein the diluent is an aromatic compound; wherein the diluent is used for inhibiting lithium dendrites generated by uneven deposition of a lithium metal negative electrode in the lithium metal battery in the circulation process, and is used for inhibiting the lithium metal negative electrode in the lithium metal battery from reacting with an electrolyte. According to the invention, the aromatic diluent is added to dilute the high-concentration lithium salt electrolyte. Therefore, the solvation structure of the lithium saltin the electrolyte is improved to accelerate lithium ion transmission; according to the electrolyte, the degree of uneven local current density on the surface of lithium metal is reduced, lithium metal deposition is homogenized, so that growth of dendrites on the surface of the lithium metal is inhibited, the electrolyte has high conductivity, low viscosity and good wettability, the coulombic efficiency of the lithium metal battery can be effectively improved, and the cycle life of the lithium metal battery is greatly prolonged.

Description

technical field [0001] The invention belongs to the technical field of lithium metal batteries, in particular to a lithium metal battery electrolyte containing aromatic compounds as diluents. Background technique [0002] Lithium metal has a higher specific capacity (3860mAh / g) and the lowest potential (-3.04V vs. standard hydrogen electrode). Lithium metal can be used as a negative electrode in lithium-sulfur batteries, lithium-air batteries, embedded cathode lithium batteries and lithium oxide cathode batteries, etc., and is a hotspot in the research of high energy density secondary batteries. However, the lithium dendrite growth and SEI film rupture that occurred during the cycle of lithium metal anodes brought safety and cycle problems to lithium metal batteries, respectively, and affected the development and commercialization of lithium metal anodes. [0003] The solution to the metal lithium anode mainly lies in controlling the morphology of lithium deposition and for...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/0567H01M10/052
CPCH01M10/052H01M10/0567H01M2300/0025Y02E60/10H01M10/0569H01M2300/0028H01M10/0525
Inventor 谢佳姜智鹏曾子琪韩智龙
Owner HUAZHONG UNIV OF SCI & TECH
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