A kind of molecular brush polymer film based on cellulose network structure and its preparation method and application

Abstract

The invention provides a molecular brush polymer film based on a cellulose network structure, a preparation method and an application thereof. The three-dimensional network structure is obtained by grafting functional polymers on cellulose through surface grafting technology, and forming a thin film through suction filtration or heating and volatilization, which serves as the gel polymer electrolyte part in the lithium battery. The network structure uses natural polymer cellulose as the skeleton and grafts functional molecular brushes to construct a new three-dimensional network structure, which can not only significantly improve the liquid absorption rate of the material, but also effectively increase the movement speed of lithium ions. In addition, on the one hand, the migration number of lithium ions can be significantly increased by grafting functional molecular brushes with lithium salt groups. On the other hand, functional molecular brushes containing alkoxy groups can increase the ionic conductivity of lithium ions and effectively improve the electrochemical performance of lithium batteries. In the process of assembling the battery, the in-situ thermal polymerization method is used to effectively reduce the interface impedance between the internal electrode and the electrolyte of the lithium metal battery.

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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