Protection method of alkali metal negative electrode, negative electrode prepared thereby and application

An alkali metal and alkali metal battery technology, applied in battery electrodes, electrical components, electrochemical generators, etc., can solve the problems of uneven metal deposition, dendrite growth, etc., achieve excellent structural integrity, reduce structural collapse and powder the effect of improving the uniformity

Active Publication Date: 2020-05-19
CENT SOUTH UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In order to solve the problems of uneven metal deposition / dissolution and dendrite growth in the cycle process of existing alkali metal batteries, the first purpose of the present invention is to provide a protection method for alkali metal negative electrodes, which aims to stack The thermally conductive carbon film protective layer obtained by one layer of the process can on the one hand uniform the current density on the electrode surface and facilitate the uniform deposition of metals. On the other hand, the protective layer can serve as a physical barrier to inhibit the further growth of dendrites and avoid Piercing the separator, thereby improving the safety performance of alkali metal batteries

Method used

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  • Protection method of alkali metal negative electrode, negative electrode prepared thereby and application
  • Protection method of alkali metal negative electrode, negative electrode prepared thereby and application
  • Protection method of alkali metal negative electrode, negative electrode prepared thereby and application

Examples

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Embodiment 1

[0058] 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 8MPa, and the roller The pressing speed is 0.5 m / min, and the temperature is 400°C. The obtained thermally conductive carbon film was cut into discs with a diameter of 15 mm. The graphene content in the thermally conductive carbon film is 20%, the porosity is 5%, and the thickness is 50 μm. Using metal lithium as the working electrode and copper foil as the counter electrode, add and stack on the surface of metal lithium and cover the surface of metal lithium sheet. (The following cases, unless otherwise stated, the setting of the protective layer is the same as this case) The thermal conductive carbon film is used as the protective layer, with 1M LiTFSI+DOL-DME+2%LiNO 3 The electrolyte is assembled into a button half cell and a ...

Embodiment 2

[0060] Compared with Example 1, the difference is that the content of graphene is changed, specifically:

[0061] 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 8MPa, and the roller The pressing speed is 0.5 m / min, and the temperature is 400°C. The obtained thermally conductive carbon film was cut into discs with a diameter of 15 mm. The graphene content in the thermally conductive carbon film is 25%, the porosity is 7%, and the thickness is 50 μm. Use metal lithium as the working electrode, copper foil as the counter electrode, add the thermally conductive carbon film on the surface of metal lithium as a protective layer, and use 1M LiTFSI+DOL-DME+2%LiNO 3 The electrolyte is assembled into a button half cell and a button symmetrical cell. at 0.1mA / cm 2 current density and 1mAh / cm...

Embodiment 3

[0063] Compared with Example 1, the difference is that the film-forming pressure is changed, specifically:

[0064] 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 0.5 m / min, and the temperature is 400°C. The obtained thermally conductive carbon film was cut into discs with a diameter of 15 mm. The graphene content in the thermally conductive carbon film is 20%, the porosity is 9%, and the thickness is 70 μm. Use metal lithium as the working electrode, copper foil as the counter electrode, add the thermally conductive carbon film on the surface of metal lithium as a protective layer, and use 1M LiTFSI+DOL-DME+2%LiNO 3 The electrolyte is assembled into a button half cell and a button symmetrical cell. at 0.1mA / cm 2 current density and 1mAh / ...

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Abstract

The invention belongs to the technical field of lithium metal batteries, and particularly discloses a protection method of an alkali metal negative electrode. The method comprises the following steps:cracking a polymer to obtain a polymer carbon material, mixing the polymer carbon material with graphene, and pressing to form a film, thereby obtaining a heat-conducting carbon film; then, stackingthe prepared heat-conducting carbon film on the surface of the alkali metal negative electrode and covering the whole surface of the alkali metal negative electrode to obtain the alkali metal negativeelectrode subjected to protection treatment. The invention also provides the alkali metal negative electrode obtained by the protection method and an alkali metal battery. The method is simple and efficient, and the original battery manufacturing process is not changed; and after the protective layer is added, the nucleation overpotential of the battery is reduced, the coulombic efficiency and the cycling stability are improved, and the battery has a great practical prospect.

Description

technical field [0001] The invention relates to the technical field of electrochemical energy storage negative electrodes, in particular to a protection method for alkali metal negative electrodes. Background technique [0002] Alkali metals such as lithium, sodium, and potassium are considered ideal anode materials for high-energy secondary batteries due to their high theoretical specific capacity and low electrochemical potential. However, due to the uneven deposition and dissolution of metals during the charging and discharging process of the battery, dendrites grow, which easily cause low Coulombic efficiency, short cycle life and even safety issues, which greatly restrict the use of alkali metals as high energy density secondary batteries. The actual application process of the secondary battery. [0003] At present, in order to solve the dendrite problem in alkali metal anodes, the solution strategies mainly include electrolyte optimization, artificial solid electrolyt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1395H01M4/62H01M4/134H01M10/052H01M10/054
CPCH01M4/134H01M4/1395H01M4/628H01M10/052H01M10/054Y02E60/10
Inventor 张治安谢杨洋高春晖赖延清张凯李劼
Owner CENT SOUTH UNIV
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