Molecular brush polymer film based on cellulose network structure, and preparation method and application thereof

Abstract

The invention provides a molecular brush polymer film based on a cellulose network structure, and a preparation method and application thereof. According to the three-dimensional network structure, functional macromolecules are grafted on cellulose through a surface grafting technology, and a film is prepared through suction filtration or heating volatilization and serves as a gel polymer electrolyte part in a lithium battery. The network structure is a novel three-dimensional network structure constructed by taking natural polymer cellulose as a skeleton and grafting with a functional molecular brush, so that not only can the liquid absorption rate of the material be obviously improved, but also the moving speed of lithium ions can be effectively improved. In addition, on one hand, the migration number of lithium ions can be obviously increased by grafting a functional molecular brush with a lithium salt group. On the other hand, the functional molecular brush contains alkoxy groups,so that the ionic conductivity of lithium ions can be improved, and the electrochemical performance of the lithium battery is effectively improved. In the process of assembling the battery, an in-situthermal polymerization method is utilized to effectively reduce the interface impedance between the internal electrode of the lithium metal battery and the electrolyte.

Description

technical field [0001] The invention relates to a preparation method of a gel polymer electrolyte with cellulose functional molecular brushes, and the electrolyte can be applied to high-performance lithium batteries. The invention relates to the preparation technology of high-performance gel polymer electrolyte and the field of lithium battery. Background technique [0002] Liquid electrolytes have problems such as leakage, volume expansion, electrode corrosion, self-discharge, poor low-temperature performance, and difficulty in designing different shapes. The gel polymer electrolyte has unique advantages, such as excellent thermal stability, which can greatly improve the safety performance of the battery. In addition, the gel polymer electrolyte can replace the electrolyte and the diaphragm of the battery at the same time, reducing the cost of the finished battery. Volume, quality, significantly increase energy density. At the same time, the excellent flexibility of polym...

AI Technical Summary

Problems solved by technology

[0003] Gel polymer electrolytes introduce plasticizers on the basis of solid polymer electrolytes, which can effectively improve the ionic conductivity of electrolytes. However, traditional gel electrolytes are usually prepared separately and then assembled into batteries together with positive and negative electrodes, which will cause the electrodes and electrolytes to On the one hand, poor interface contact will increase the internal resistance of the battery, and on the other hand, it will cause the electrode and electrolyte to separate when the bending strength is relatively large. Therefore, exploring in-situ polymerization technology is very important for reducing battery impedance. Significance

At the same time, the gel polymer electrolyte contains part of the liquid phase components, which cannot completely solve the safety problems caused by the liquid electrolyte.

In addition, compared with solid polymer electrolytes, the mechanical strength of gel polymer electrolytes is relatively low, and it is difficult to suppress the penetration of lithium dendrites during charge and discharge cycles of lithium metal batteries.

[0004] The above-mentioned gel polymer electrolytes cannot solve the problems of excessive battery internal resistance, safety issues caused by liquid phase components, and insufficient mechanical strength to inhibit lithium dendrite piercing.

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