Cellulose-based functional diaphragm as well as preparation method and application thereof

A cellulose-based technology, applied in the field of electrochemical energy storage, can solve the problems of limited ability to maintain electrolyte, poor thermal stability, affecting the safety and electrochemical performance of lithium batteries, and is conducive to large-scale production and raw materials. Inexpensive and accessible effects

Pending Publication Date: 2020-11-10
HUNAN AGRICULTURAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the most widely used in the market is the polyolefin separator. Although it has good chemical stability and good mechanical properties, it still has shortcomings such as poor thermal stability and limited ability to maintain electrolyte.
Seriously affect the safety and electrochemical performance of lithium batteries
Moreover, the electrochemical properties (such as conductivity, internal resistance, ion migration number, decomposition voltage, etc.) of the above-mentioned separators still need to be further improved.

Method used

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  • Cellulose-based functional diaphragm as well as preparation method and application thereof
  • Cellulose-based functional diaphragm as well as preparation method and application thereof
  • Cellulose-based functional diaphragm as well as preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Example 1 Preparation of cellulose acetate-based diaphragm (CPP film) by liquid phase casting

[0031] Mix CA:PVDF:PEG at a mass ratio of 8:3:2, the total weight is 0.65g, put the mixed sample into a 20mL screw-top glass reagent bottle, add 10mL N,N-dimethylacetamide, Put in tetrafluoroethylene magnets and stir in a collector-type constant temperature heating magnetic stirrer at 60°C for 8 hours. If it is not fully dissolved, increase the temperature to 80°C and stir for another 2 hours. Put the stirred solution into an electric constant temperature blast drying oven at 80°C for 2 hours for defoaming, slowly pour the prepared solution into an ultra-flat petri dish, and gently shake the petri dish to make the glue evenly distributed. Dry the petri dish in a blast drying oven. After N,N-dimethylacetamide is dried, soak the diaphragm with distilled water, put it on a glass plate, and place it in a vacuum drying oven at 80°C for 12 hours in vacuum. . The resulting diaphra...

Embodiment 2

[0032] Embodiment 2 prepares cellulose acetate-based diaphragm (PCP film) with liquid phase coating method

[0033] Mix CA:PVDF:PEG according to the mass ratio of 4:8:3, the total weight is 3g, put it into a 20ml glass reagent bottle, then add 10ml N,N-dimethylacetamide, put it into the tetrafluoroethylene magnet, Stir at 60° C. for 12 hours in a collector-type constant temperature heating magnetic stirrer. Put the stirred solution into a blast drying oven at 80°C for 2 hours for defoaming, slowly pour the prepared solution onto a glass plate, scrape off the diaphragm with a 200μm-high coating film preparer, and then use a 1:1 Rinse with ethanol and water solution, then soak the diaphragm in deionized water tank for 5 minutes, stick the obtained diaphragm on a glass plate with a little ethanol, put it in a blast dryer for 6 hours at 80°C, and then transfer it to a vacuum drying oven for 80 °C for 12 hours in vacuum. The resulting diaphragm was sandwiched between two large we...

Embodiment 3

[0034] Embodiment 3 performance test

[0035] 3.1 Thermogravimetric analysis

[0036]The diaphragm prepared by embodiment 1 and 2 is carried out thermogravimetric analysis, and testing result is as follows figure 2 shown. Depend on figure 2 It can be seen that the CPP film prepared by the liquid phase casting method has obvious quality and shape changes after 300 ° C, indicating that the CPP film begins to decompose at this time. The PCP film prepared by liquid phase coating began to change obviously in quality and shape at 320℃. According to thermogravimetric analysis, the decomposition temperature of the above two separators is above 300°C, which is much higher than the decomposition temperature of the commercial Celgard (M825) separator at about 165°C (PE melting temperature). Therefore, the separators prepared in the present application have significantly improved thermal stability.

[0037] The separators prepared in Examples 1 and 2 and the commercialized separato...

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Abstract

The invention discloses a cellulose-based functional diaphragm as well as a preparation method and application thereof. The diaphragm is mainly prepared by blending a support phase, a hydrophilic compound and a toughening agent, wherein the support phase is selected from polymers obtained by polymerization reaction of olefin compounds and derivatives thereof; and the hydrophilic compound is selected from cellulose or a derivative thereof. The cellulose-based functional diaphragm is obviously superior to a commercial Celgard membrane at the aspects of chemical stability, electrolyte keeping capacity and electrochemical performance (such as conductivity, internal resistance, ion mobility, decomposition voltage and the like) and the like. Besides, the raw materials of the cellulose-based functional diaphragm are cheap and are easy to obtain, excessive instruments and devices are not needed in the preparation process, and the large-scale production is facilitated.

Description

technical field [0001] The invention relates to the technical field of electrochemical energy storage, in particular to a cellulose-based functionalized diaphragm and a preparation method and application thereof. Background technique [0002] Lithium batteries are considered to be one of the most valuable and important energy storage systems at home and abroad. However, with the development of society, the demand for high specific energy storage devices has increased, which has promoted the research of lithium-ion batteries. Among them, the diaphragm, as an important part of the lithium battery, has a great influence on the capacity, safety performance, and cycle stability of the lithium battery. The main function of the separator is to separate the positive and negative electrodes of the lithium battery to prevent the short circuit of the two electrodes due to contact. At the same time, the separator must have a certain porosity to allow ions to pass through and good mecha...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525
CPCH01M10/0525Y02E60/10
Inventor 周鹏晟吴雄伟邓奇曾宪祥王泓睿许雨婷周春姣张薇
Owner HUNAN AGRICULTURAL UNIV
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