Self-supporting lithium metal anode and its preparation and application

A self-supporting, metal lithium technology, applied in the direction of negative electrodes, battery electrodes, lithium batteries, etc., can solve the problems of poor lithium affinity of metal lithium negative electrode framework, reduced Coulombic efficiency and cycle life, and inability to achieve uniform deposition, etc., to achieve excellent battery life. Effects of chemical properties, improved performance, and improved long-cycle performance

Active Publication Date: 2021-06-22
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, the existing metal lithium negative electrode framework has the following disadvantages: 1) the use of metal mesh framework itself as an inert current collector, and its mass is relatively large, will reduce the energy density of the battery, which runs counter to the original intention of using metal lithium negative electrode to increase the energy density; 2) The Lithophilicity of the lithium metal negative electrode framework is poor, and uniform deposition cannot be achieved in the process of melting or electrochemical deposition, which easily leads to a decrease in Coulombic efficiency and cycle life

Method used

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  • Self-supporting lithium metal anode and its preparation and application
  • Self-supporting lithium metal anode and its preparation and application
  • Self-supporting lithium metal anode and its preparation and application

Examples

Experimental program
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Effect test

Embodiment 1

[0060] A mixture obtained by mixing polymer polyimide with graphene after carbonization at 800°C for 2 hours was selected, and then pressed into a film in a hot roller press to obtain a thermally conductive carbon film. The film-forming pressure was 6MPa, and the roller The pressing speed is 1.2m / min, and the temperature is 400°C. The obtained thermally conductive carbon film was cut into discs with a diameter of 13 mm. The graphene content in the thermally conductive carbon film is 20%, the porosity is 20%, and the thickness is 0.3mm. Use thermal conductive carbon film as metal lithium working electrode, metal lithium sheet as counter electrode, 1M LiTFSI+DOL-DME+2% LiNO 3 Assemble a button cell for the electrolyte. Electrochemical tests were carried out by loading lithium metal in the thermally conductive carbon film by means of electrochemical deposition. at 1mA / cm 2 current density and 1mAh / cm 2 Under the area capacity, the average Coulombic efficiency reaches 98.6%, ...

Embodiment 2

[0062] Compared with Example 1, the difference is that the melting method is used to fill lithium metal and prepare it into a symmetrical battery, specifically:

[0063] The same method as in Example 1 was used to obtain the thermally conductive carbon film disc. Metal lithium is poured into the thermally conductive carbon film by high-temperature melting, and after cooling, the thermally conductive carbon film composite metal lithium is used as the working electrode, and 1M LiTFSI+DOL-DME+2%LiNO 3 Assemble a button-type symmetrical battery for the electrolyte. at 1mA / cm 2 current density and 1mAh / cm 2 Under the area capacity, it can be cycled stably for 300 hours, and the polarization voltage is only 22mV.

Embodiment 3

[0065] Compared with Example 1, the difference is that the content of graphene is changed, specifically:

[0066] A mixture of polymer polyimide carbonized at 800°C for 2 hours and graphene was selected to form a film in a hot roller press. The film forming pressure was 6MPa, the rolling speed was 1.2m / min, and the temperature was 400°C. The obtained thermally conductive carbon film was cut into discs with a diameter of 13 mm. Wherein, the graphene content in the thermally conductive carbon film is 25%, the porosity is 26%, and the thickness is 0.2mm. Use thermal conductive carbon film as metal lithium working electrode, metal lithium sheet as counter electrode, 1M LiTFSI+DOL-DME+2% LiNO 3 Assemble a button cell for the electrolyte. Electrochemical tests were carried out by loading lithium metal in the thermally conductive carbon film by means of electrochemical deposition. at 1mA / cm 2 current density and 1mAh / cm 2 Under the area capacity, the average Coulombic efficienc...

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Abstract

The invention belongs to the technical field of lithium metal batteries, and specifically relates to a preparation method of a self-supporting metal lithium negative electrode, comprising the following steps: step (1): cracking a polymer to obtain a polymer carbon material, and combining the polymer carbon material and graphene Mixing and pressing to form a film to obtain the self-supporting heat-conducting carbon film; step (2): Deposit metal lithium in the self-supporting heat-conducting carbon film by high-temperature melting or electrochemical deposition to obtain the self-supporting heat-conducting carbon film Lithium metal anode. The invention also discloses the lithium metal battery negative electrode prepared by the preparation method and its application. The negative electrode prepared by the preparation method of the present invention has the advantages of light weight and flexibility, high mechanical properties, adjustable porosity, and controllable thickness. When used as a metal lithium negative electrode, the current density can be reduced, lithium can be deposited uniformly, and high coulombic efficiency and long life can be obtained. Cycling stable metal lithium battery.

Description

technical field [0001] The invention relates to the technical field of electrochemical energy storage negative electrodes, in particular to a lithium metal negative electrode material. Background technique [0002] The successful commercialization of lithium-ion batteries has greatly promoted the progress of battery technology and the convenience of people's lives. However, with the growing demand for high capacity and flexibility of portable batteries, the development of flexible batteries with higher energy density has become a key scientific issue in the field of energy storage technology. Lithium metal is considered as an ideal high-energy secondary battery material due to its high theoretical specific capacity and low electrochemical potential. What is different from the anode of a conventional lithium-ion battery is the intercalation and extraction of lithium ions in the graphite anode; the charging and discharging process of the lithium metal battery anode is the dis...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/134H01M4/1395H01M4/38H01M4/66H01M10/052
CPCH01M4/134H01M4/1395H01M4/382H01M4/663H01M10/052H01M2004/027Y02E60/10
Inventor 张治安谢杨洋郑景强赖延清张凯李劼
Owner CENT SOUTH UNIV
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