Preparation method of lithium-sulfur battery positive electrode

A lithium-sulfur battery and cathode technology, which is applied in the field of preparation of lithium-sulfur battery cathodes, can solve the problems of surface tension and volume shrinkage electrode cracks, dilute the theoretical energy density of lithium-sulfur batteries, and reduce the volumetric energy density of lithium-sulfur batteries. Avoid local agglomeration of materials, good electrode structure and compositional homogeneity, and promote the effect of dissolution and reaction

Inactive Publication Date: 2020-02-04
TONGJI UNIV
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Problems solved by technology

[0005] 2) Excessive electrolyte addition seriously dilutes the theoretical energy density of lithium-sulfur batteries
The addition of too many conductive additives causes huge surface tension and volume shrinkage inside the electrode sheet during the solvent volatilization process, resulting in electrode cracking, which limits the preparation of high-capacity lithium-sulfur battery cathodes
Although t

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  • Preparation method of lithium-sulfur battery positive electrode
  • Preparation method of lithium-sulfur battery positive electrode
  • Preparation method of lithium-sulfur battery positive electrode

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Example Embodiment

[0034] The method for preparing lithium-sulfur battery anode provided by the present invention includes the following steps:

[0035] Step 1. Mix the active material sulfur, conductive agent, and binder uniformly to obtain a mixture, and then add a dispersing solvent to the mixture and mix uniformly to obtain an electrode slurry;

[0036] Step 2, uniformly coating the electrode slurry on the positive electrode current collector to obtain a wet electrode coated with the slurry;

[0037] Step 3. Place the wet electrode coated with the slurry in a low temperature environment of -80°C to -5°C and freeze for 1 hour to 5 hours until the wet electrode is frozen and formed so that the dispersed solvent in the wet electrode is solidified and crystallized to obtain a solidified electrode;

[0038] Step 4. Place the solidified electrode in a vacuum environment with a vacuum degree of 0.1 Pa-100 Pa for 1 hour to 5 hours to sublime the solid phase of ice crystals in the solidified electrode;

[0039...

Example Embodiment

[0054]

[0055] 2g commercial sublimation sulfur powder, 0.53g Ketjen black (ECP 200JD), 2.66g styrene butadiene rubber and carboxymethyl cellulose mixed binder aqueous solution (the mass ratio of SBR and CMC is 1:1, the binder aqueous solution is solid Phase content is 5%), and successively add 50ml ball milling tank (sulfur, Ketjen black, the mass ratio of binder is 75:20:5), then add appropriate amount of ball milling beads and 8g of water, and then at 350 rpm After ball milling for 2 hours at the speed of 100 millimeters, the uniformly ball-milled electrode slurry was evenly and evenly coated on the current collector aluminum foil with an automatic coating machine, and the coating thickness was controlled at 200 microns to obtain a wet electrode. Then, the wet electrode was quickly obtained. The electrode is placed in a freezing environment of minus 40 degrees to solidify the water solvent into ice crystals. The freezing time is 2 hours. Finally, the frozen solidified electr...

Example Embodiment

[0064]

[0065] Add 2g commercial sublimation sulfur powder, 0.875g Ketjen black (ECP 600JD), 1.66g LA133 binder aqueous solution (the solid content of the binder aqueous solution is 15%) into a 50ml ball mill (sulfur, Ketjen black, bonding The agent mass ratio is 64:28:8), then add a proper amount of ball milling beads and 8g of water, and then ball mill for 2 hours at a speed of 350 revolutions per minute, and then use an automatic coating machine for the uniform electrode slurry obtained by ball milling Coat evenly and evenly on the current collector aluminum foil, the coating thickness is controlled at 300 microns to obtain a wet electrode, and then quickly place the prepared wet electrode in a freezing environment of minus 30 degrees to solidify the water solvent into ice crystals. The freezing time is After 2 hours, finally take out the frozen solidified electrode and place it in a vacuum environment with a vacuum of 0.1 Pa for 2 hours to sublime the ice crystals solidifie...

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Abstract

The invention provides a preparation method of a lithium-sulfur battery positive electrode. The preparation method comprises the following steps: uniformly mixing an active substance sulfur, a conductive agent and a binder to obtain a mixture, then adding a dispersing solvent into the mixture, and uniformly mixing to obtain electrode slurry; uniformly coating a positive electrode current collectorwith the electrode slurry to obtain a wet electrode coated with the slurry; freezing the wet electrode coated with the slurry in a low-temperature environment of -80 to -5 DEG C for 1-5 hours until the wet electrode is frozen and formed, so that the dispersing solvent in the wet electrode is solidified and crystallized to obtain a solidified electrode; placing the solidified electrode in a vacuumenvironment with the vacuum degree of 0.1-100Pa for 1-5 hours, so that solid-phase sublimation of ice crystals in the solidified electrode is carried out to obtain a solid-phase sublimated electrode;and carrying out rolling treatment on the solid-phase sublimated electrode, and controlling the porosity of the electrode to be 50-70% to obtain the lithium-sulfur battery positive electrode. The preparation method is simple, and the problem of electrode cracking in the preparation of a high-sulfur-carrying positive electrode by adopting a traditional hot drying method is effectively solved.

Description

technical field [0001] The invention belongs to the field of lithium batteries, and in particular relates to a method for preparing a positive electrode of a lithium-sulfur battery. Background technique [0002] With the development of portable electronic products, energy storage technology and new energy vehicles, modern society has put forward higher requirements for battery energy density. Lithium-ion batteries are limited by the intercalation / extraction reaction mechanism of electrode materials, and there is little room for improvement in their energy density. Moreover, the current lithium-ion battery cathode material is mainly composed of transition metal oxides, and its raw material cost has been high. It is imminent to develop a new generation of new battery systems with high energy density and low cost. Lithium-sulfur batteries have a high specific capacity (1672mAhg -1 ) and energy density (2600Wh kg -1 ), and the positive electrode material is rich in elemental...

Claims

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Application Information

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IPC IPC(8): H01M4/139H01M4/04H01M10/052
CPCH01M4/139H01M4/04H01M10/052Y02E60/10
Inventor 谢勇李洒伽龙黄云辉潘国宇
Owner TONGJI UNIV
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