Preparation method of multi-polarization-center carbon nanotube/lithium vanadate composite membrane and application of multi-polarization-center carbon nanotube/lithium vanadate composite membrane in catalysis of reaction of lithium-sulfur battery

Abstract

The invention relates to a preparation method of a multi-polarization-center carbon nanotube / lithium vanadate composite membrane and an application of the multi-polarization-center carbon nanotube / lithium vanadate composite membrane in catalysis of a reaction of a lithium-sulfur battery. In the process of preparing carbon nano tube aerogel by using a chemical vapor deposition method, before the carbon nano tube aerogel is suspended in the air and agglomerated, the nano powder with NH4VO3 is blown into the carbon nanotube gel at a high speed through airflow transportation so as to directly compound to form the membrane. Rolling, heat treatment and lithiation are conducted to obtain Li3V2O5 containing multiple polarization centers, Li ions are inserted into a V2O5 crystal structure to obtain O atoms with high electronegativity to form a high negative potential center, a high positive potential center is formed by Li and V, and Li-S, V-S and Li-O chemical bonds are formed with polar LiPS for adsorption, thereby effectively fixing LiPS, and avoiding loss of active substances. The carbon nanotube / Li3V2O5 composite membrane is used as an S host with continuous and good electric contact. The optimal electron transport and electrochemical performance can be realized, the reaction sites available for electrochemistry are maximized, and meanwhile, stronger physical support is provided.

Description

technical field [0001] The present invention relates to a kind of catalyzer of composite carbon nanotube film, and this catalyzer is vanadium pentoxide (V 2 o 5 ) Lithium vanadate (Li 3 V 2 o 5 ), Li 3 V 2 o 5 The highly electronegative O atom attracts Li and V electron clouds to form two positive potential and one negative potential polarization center, and the multi-polarization center is more effective in riveting active materials and catalyzing the reaction of lithium-sulfur batteries (Li-S). Background technique [0002] The limited capacity and high cost of current commercial lithium-ion batteries (LIBs) are difficult to meet the ever-increasing demand for energy storage. The main active substance S of Li-S has a high content in the earth's crust, low cost and no pollution to the environment, especially its ultra-high theoretical specific capacity (1675 mA h g -1 ) and energy density (2600 Wh kg -1 ) is considered to be one of the most promising next-generatio...

AI Technical Summary

Problems solved by technology

[0004] However, due to the weak electronegativity of the catalytic sites of the above-mentioned materials, the adsorption strength of LiPS is limited, the catalytic effect is not good, and the adsorption method is single, which cannot meet the needs of accurate adsorption of various long-chain LiPS, resulting in the electrochemical reaction speed Limited, making the battery charge and discharge slow, capacity loss

And most of the above materials are in the form of powder or non-nano materials, which may need to be mixed with other binders in the process of preparing intermediates. The binder has no catalytic effect, but will eliminate the active sites and increase the non-catalytic interface. The insulating binder will also reduce the conductivity of the catalytic layer, resulting in the catalyst not having good electrical contact and unable to exert its catalytic performance

There is no good volume expansion ability to accommodate active materials, and the interface contact between the positive electrode and the modified separator is not good, resulting in the destruction of ion / electron transfer power and unsatisfactory performance in the battery, which ultimately shortens the battery life.