Sulfur-nitrogen dual-doped graphene nano material and preparation method and application thereof

Abstract

The invention provides a sulfur-nitrogen dual-doped graphene nano material. A preparation method of the sulfur-nitrogen dual-doped graphene nano material comprises the following steps: mixing a sulfur nitrogen precursor and graphene oxide to obtain a mixture I, adding the mixture I into ethanol, ultrasonically and uniformly dispersing, and drying at 40 to 90 DEG C, thus obtaining a composite of the graphene oxide and the sulfur nitrogen precursor; and standing the composite of the graphene oxide and the sulfur nitrogen precursor at a high temperature of 800 to 1000 DEG C for 1 to 5 hours under the protection of inert gas, then naturally cooling to the room temperature, and obtaining a final product. The preparation method is low in cost; by combining a two-dimensional structure of the graphene and doping-induced polarity active site, the conductivity of a positive electrode of a lithium sulfur battery is remarkably improved, the loss and reutilization of polysulfide are improved, and when the prepared sulfur nitrogen dual-doped graphene nano material is used as a multifunctional interlayer material to be applied to the lithium sulfur battery, the conductivity of the sulfur positive electrode and the completeness of a protection diaphragm under large current can be remarkably improved, and the applicability is high.

Description

[0001] (1) Technical field [0002] The present invention relates to the research field of nanomaterials, in particular to a sulfur-nitrogen double-doped graphene nanomaterial and its preparation method and application. The sulfur-nitrogen double-doped graphene nanomaterial can be used as a multifunctional interlayer material in lithium-sulfur batteries , in order to improve its electrochemical performance and protect the separator. [0003] (2) Background technology [0004] With the rapid development of society, there is an increasing demand for batteries with high energy density and high stability to meet the needs of electric vehicles and large-scale energy storage. Lithium-sulfur battery has attracted much attention because of its high theoretical energy density (1675mAh / g and 2600kWh / kg), and uses low-cost and environmentally friendly sulfur as the active material. It is considered to be a new generation of battery system with great potential. However, the commercializat...

AI Technical Summary

Problems solved by technology

However, the commercialization of lithium-sulfur batteries needs to solve the following three problems: (1) The conductivity of sulfur is poor (5×10 -30 S cm -1 ), resulting in low utilization rate of sulfur and low actual capacity; (2) during the charging and discharging process, due to the interconversion of sulfur and solid discharge products, the structure and morphology of the electrode change, which in turn affects the cycle stability of the battery; ( 3) During the charging and discharging process, the polysulfides produced will dissolve and lose into the electrolyte, causing problems such as battery efficiency and capacity decay

Most of its use in lithium-sulfur batteries is limited to recombination with sulfur, but due to the non-polar surface characteristics of carbon and its two-dimensional structure, its effect as a host material for sulfur is limited.

Images