Preparation method of composite functionalized membrane

Abstract

The invention discloses a preparation method of a composite functionalized membrane. The composite functionalized membrane is composited by diatomic doped reduction graphene oxide and a commercial polymer membrane, and is applied to a lithium sulfur battery; the diatomic nitrogen-sulfur doped reduction graphene oxide composite material uses the reduction graphene oxide as a conductive matrix, andthe hetero atoms nitrogen and sulfur adsorb lithium polysulfide through an electrostatic interaction to weaken the "shuttle effect", so as to further coat the diatomic nitrogen-sulfur doped reductiongraphene oxide composite material on the commercial polypropylene membrane to increase the capacity and charge and discharge stability of the lithium-sulfur battery. The nitrogen and sulfur double-doped reduction graphene oxide is obtained by selecting graphene oxide, L-cysteine hydrochloride, ammonia water and deionized water, performing reduction and doping through hydrothermal reaction, performing vacuum filtration, and then performing freeze drying. In addition, the acetylene black / sulfur composite is selected as the positive electrode of the lithium-sulfur battery, and the preparation process is only one step of simple sulfur melt diffusion. The preparation method of the composite functionalized membrane has simple process and low cost, and the lithium sulfur battery shows excellent electrochemical performances.

Description

technical field [0001] The invention relates to a modified commercial polymer diaphragm, in particular to a preparation method of a composite functional diaphragm, which belongs to the technical field of advanced composite material preparation technology. Background technique [0002] Energy issues are closely related to human life. Currently commercial lithium-ion batteries (for example, lithium cobalt oxide / carbon batteries) are increasingly unable to meet people's needs due to the limitation of low theoretical energy density. Therefore, the development of energy storage systems with high energy density, long cycle life, high efficiency, and low cost is crucial for applications in transportation, grid energy storage, electric vehicles, and portable electronic devices. Lithium-sulfur batteries stand out from many energy storage systems. The redox reaction of two electrons endows the two electrodes with a high theoretical capacity (lithium: 3860 mAh per gram, sulfur: 1675 m...

AI Technical Summary

Problems solved by technology

Despite these advantages, the practical application of lithium-sulfur batteries still faces the following problems: (1) the elemental sulfur and the final products (lithium sulfide and lithium disulfide) have extremely poor electrical conductivity, resulting in poor cycle stability and low coulombic efficiency. Problem; (2) During the charging and discharging process, the intermediate product lithium polysulfide will lead to "shuttle effect" driven by the concentration difference, causing irreversible consumption of active materials, further causing anode corrosion, low Coulombic efficiency and fast capacity decay, etc. Problem; (3) During the charging and discharging process, the active electrode will undergo serious volume changes, resulting in the crushing of the electrode material

These factors all lead to loss of active material and rapid capacity fading

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