Modified graphite separator for lithium-sulfur battery, preparation method of modified graphite separator and lithium-sulfur battery
A graphite-modified, lithium-sulfur battery technology, applied in secondary batteries, battery components, circuits, etc., can solve the problems of low rate performance, low cycle stability, etc., achieve low production cost, improve utilization rate, and strong control effect
Inactive Publication Date: 2017-02-22
SICHUAN UNIV
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Problems solved by technology
[0004] Aiming at the deficiencies of the prior art, the first object of the present invention is to provide a graphite-modified diaphragm for lithium-sulfur batteries, to solve the problems caused by the shuttle effect of polysulfides in lithium-sulfur batteries. The problem of low rate performance and low cycle stability performance; the second invention purpose of the present invention is to provide the preparation method of the above-mentioned graphite modified diaphragm, improve the electrochemical performance of lithium-sulfur battery in a simple and cheap way, and realize industrialization Large-scale application; the third object of the present invention is to provide a lithium-sulfur battery using the above-mentioned graphite modified diaphragm
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preparation example Construction
[0033] Preparation of graphite modified diaphragm:
[0034] (1) Mesophase carbon microspheres, acetylene black, and PVDF binder are mixed and ground for 0.5h to fully mix to obtain a mixture, wherein the quality of mesocarbon microspheres accounts for 70% of the sum of acetylene black and PVDF mass, The mass of acetylene black accounts for 10% of the sum of the mass of acetylene black, mesocarbon microspheres, and PVDF, and the balance is the adhesive PVDF; the obtained mixture is mixed with NMP solvent and stirred for 1 min to form a slurry. The agent is completely dissolved and the graphite and carbon materials can be dispersed to form a slurry, and then the resulting slurry is ultrasonically dispersed for 0.5h until it is fully dispersed and uniform;
[0035] (2) Evenly coat the ultrasonically dispersed slurry on one side of the polypropylene microporous membrane Celgard 2500 (diaphragm base material) through the discharge groove on the scraper, and control the thickness of...
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The invention provides a modified graphite separator for a lithium-sulfur battery. The modified graphite separator comprises a separator substrate material and a modified graphite material coating layer, wherein the modified graphite material coating layer is coated on the separator substrate material, the modified graphite material coating layer comprises the following constituents based on percent by mass: 70-85% of graphite and 5-10% of carbon material with the balance being adhesive. The invention also provides a preparation method of the abovementioned modified graphite separator and the lithium-sulfur battery assembled by employing the modified graphite separator. After initial discharge of the lithium-sulfur battery employing the modified graphite separator, a stable SEI film is formed on a surface of the modified graphite separator, the stable SEI film is used for preventing an electrolyte from being further decomposed and graphite from being stripped, and the graphite coating layer can stably exist in a super concentrated ether electrolyte; and the shuttling of a polysulfide is suppressed by a graphite layer of the SEI film formed on the surface, and the cycle performance and the rate performance of the lithium-sulfur battery are remarkably improved.
Description
technical field [0001] The invention belongs to the field of lithium-sulfur batteries, and in particular relates to a separator for lithium-sulfur batteries, a preparation method thereof and a lithium-sulfur battery composed of the same. Background technique [0002] Lithium-sulfur batteries usually use sulfur composite materials or sulfur single substance as the positive electrode active material, and metal lithium or other lithium-containing compounds as the negative electrode active material. Has a high theoretical specific capacity (1675mAh g -1 ) and energy density (2600Wh kg -1 ), low cost, relatively good safety, etc., are considered to be one of the most promising new secondary battery systems. However, the development of lithium-sulfur battery technology faces many challenges. For example, sulfur and the discharge product solid lithium sulfide are insulators of electrons and ions, resulting in low utilization of active materials, low rate capacity and high overpot...
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IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/431H01M50/44H01M50/443H01M50/489
CPCH01M10/0525H01M50/403H01M50/431Y02E60/10
Inventor 陈云贵曾攀韩亚苗黄利武
Owner SICHUAN UNIV