Secondary lithium cell using sulfurized crosslinking PVC as cathode material

Abstract

Cathode material is composed of 60-70%(Wt) sulfurization crosslinking PVC, 10-15% binder; 15-30% conduction agent. Preparation method includes following steps: obtaining solution of sodium polysulphide by dissolving mixed anhydrous sodium sulfide and sublimed sulfur in solvent of N,N-dimethylformamide; obtaining solution of PVC by dissolving PVC in solvent of N,N-dimethylformamide; obtaining sulfurization crosslinking PVC by dropping solution of sodium polysulphide to solution of PVC; powder product is obtained after dry. The disclosed cathode material grafts structure of multi sulfur linkage to framework of chain polymer to fix up S-S structure. Features are: no pollution in synthesizing process, high energy density and favorable charging and discharging cycle.

Description

technical field [0001] The invention relates to a secondary lithium battery using vulcanized cross-linked polyvinyl chloride as a cathode material and a preparation method thereof, belonging to the secondary lithium battery technology. Background technique [0002] In recent years, lithium-ion batteries have gradually become an important part of the field of chemical power sources, and their application potential in the environmentally friendly and clean power systems of electric vehicles has also attracted more and more researchers to join the research on lithium-ion batteries. In lithium-ion battery systems, polysulfide cathode materials have become one of the replacement candidates for existing cathode materials due to their low cost and high energy density, so the research on polysulfide electrode materials is very extensive. For example, Naoi synthesized dithiodianiline polymer cathode material for the first time in 1997 (J. Electrochem. ...

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Problems solved by technology

For example, Naoi synthesized dithiodianiline polymer cathode material for the first time in 1997 (J. Electrochem. Soc., 1997, 144 (6): L173) and obtained 270mAh g in lithium battery system -1 Discharge specific capacity, but due to the expensive raw materials and complex synthesis process of such materials, it is difficult to be practically applied; Skotheim applied polycarbon disulfide (PCS) electrodes to secondary lithium batteries and obtained better discharge capacity and cycle performance (US Patent, 5460905), but the pollution to the environment during the synthesis process can not be ignored; Hyun KyungSung synthesized sulfurized polybutadiene (SPB) lithium battery cathode material with polybutadiene as the matrix and obtained 325mAh g -1 Discharge capacity (US Patent, 6335118); Wang Jiulin used high temperature (300°C-400°C) dehydrogenation method to achieve branched crosslinking of S-S structure on polyethylene oxide, polyvinylidene fluoride and other polymer substrates (CN1339839A) , due to the continuous generation of corrosive gases during the synthesis process, it has a great impact on the environment and equipment, so there are certain defects in this synthesis route

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