Preparation method of perfluoroalkyl sulfonimide lithium polymer electrolyte and lithium-sulfur secondary cell

Abstract

The invention discloses a preparation method of perfluoroalkyl sulfonimide lithium polymer electrolyte. The preparation method comprises the following steps: reacting sodium methanesulfonamide with hexamethyldisilazane at a certain temperature so as to obtain an intermediate, adding the obtained intermediate and perfluorinated sulfonyl fluoride resin into a solvent, carrying out similar-conversion reactions at a certain temperature, after the reactions subjecting the reaction product to suction filtration, washing, and drying so as to obtain perfluoroalkyl sulfonimide sodium polymer; then stirring to fully dissolve the polymer in a hermetical space at a certain temperature, evenly painting the polymer on a substrate, drying so as to form a membrane on the substrate, demoulding so as to obtain a Na-type polymer membrane; and finally replacing the Na+ in the membrane by Li+ so as to obtain a Li-type perfluoroalkyl sulfonimide polymer electrolyte membrane. The invention further provides a lithium-sulfur secondary cell, which comprises a lithium negative electrode, a positive electrode sheet, an organic electrolyte, and the provided Li-type perfluoroalkyl sulfonimide polymer electrolyte membrane. The lithium-sulfur secondary cell has the advantages of high gram volume of active substances during the charge / discharge process, little dissolution loss of active substances, and long cycle life.

Description

technical field [0001] The invention relates to the preparation of a functional electrolyte membrane and a corresponding lithium-sulfur battery, in particular to a preparation method of a perfluoroalkylsulfonimide lithium polymer electrolyte and a lithium-sulfur secondary battery. Background technique [0002] The rapid development of smaller, lighter and higher-performance electronic communication equipment has made people put forward higher and higher requirements on the performance of chemical power sources, especially the energy density of batteries. Li-S battery, as one of the currently known lithium-ion secondary battery systems with the highest energy density, has received more and more attention. Although the achievable energy density of lithium-sulfur batteries has reached 300-400Wh / kg, the sulfur positive electrode is not conductive, the electrochemical reaction process is complicated, and the lithium negative electrode has high activity. The intermediate product l...

AI Technical Summary

Problems solved by technology

Although the achievable energy density of lithium-sulfur batteries has reached 300-400Wh / kg, the sulfur positive electrode is not conductive, the electrochemical reaction process is complicated, and the lithium negative electrode is highly active. The intermediate product lithium polysulfide in the charging and discharging process of lithium-sulfur batteries dissolves in the electrolyte. , in the liquid phase diffuses to the negative electrode through the porous diaphragm (that is, the "shuttle effect"), resulting in the consumption of positive active materials and the corrosion and passivation of the negative electrode, which seriously affects the cycle performance of lithium-sulfur batteries

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