CN-122000453-A - MOF-loaded PET-based diaphragm composite ether-cyano high-voltage electrolyte type gel electrolyte and preparation method and application thereof

CN122000453ACN 122000453 ACN122000453 ACN 122000453ACN-122000453-A

Abstract

The invention discloses a MOF-loaded PET-based diaphragm composite ether-cyano high-voltage electrolyte gel electrolyte, a preparation method and application thereof, wherein the MOF-loaded PET-based diaphragm composite ether-cyano high-voltage electrolyte gel electrolyte comprises an MOF-loaded PET-based diaphragm and an ether-cyano high-voltage electrolyte gel positioned on the MOF-loaded PET-based diaphragm, and the ether-cyano high-voltage electrolyte gel is formed by pouring an ether-cyano high-voltage electrolyte gel precursor liquid on the MOF-loaded PET-based diaphragm, wherein the ether-cyano high-voltage electrolyte gel precursor liquid comprises a polymer, an ether-cyano difunctional high-voltage electrolyte liquid, a lithium salt and a solvent. The composite system has high ionic conductivity, high lithium ion migration number, remarkably improved oxidation and decomposition resistance and high Young modulus, can effectively inhibit lithium dendrite puncture, and cooperatively realizes stable circulation under the high-voltage condition of 4.6V (vs. Li + /Li).

Inventors

HU WEI
Yu Yinuo
YANG HUAI
XIA XINCHAO
XIAO YIXIAN
CHEN JIAJUN
XIE WENTING

Assignees

北京科技大学

Dates

Publication Date: 20260508
Application Date: 20260206

Claims (10)

1. The MOF-loaded PET-based diaphragm composite ether-cyano high-voltage electrolyte type gel electrolyte is characterized by comprising an MOF-loaded PET-based diaphragm and ether-cyano high-voltage electrolyte gel positioned on the MOF-loaded PET-based diaphragm, wherein the ether-cyano high-voltage electrolyte gel is formed by pouring an ether-cyano high-voltage electrolyte gel precursor liquid on the MOF-loaded PET-based diaphragm, and the ether-cyano high-voltage electrolyte gel precursor liquid comprises a polymer, an ether-cyano dual-function high-voltage electrolyte liquid, a lithium salt and a solvent.
2. The MOF-loaded PET-based separator composite ether-cyano high-voltage electrolyte type gel electrolyte of claim 1, wherein the preparation method of the MOF-loaded PET-based separator comprises the following steps: Soaking PET non-woven fabric in hydrochloric acid solution to obtain activated PET non-woven fabric, soaking the activated PET non-woven fabric in methanol solution containing an amino silane coupling agent, taking out, soaking in metal ion solution, adding organic ligand solution, standing at room temperature to obtain PET non-woven fabric with MOF grown in situ, washing the PET non-woven fabric with MOF grown in situ in methanol water solution, and drying to obtain the PET-based diaphragm loaded with MOF.
3. The MOF-loaded PET-based diaphragm composite ether-cyano high-pressure electrolyte gel electrolyte according to claim 2, wherein the thickness of the PET non-woven fabric is 5-100 μm, the porosity is 20-80%, the soaking time of the PET non-woven fabric in a hydrochloric acid solution is 10-60 minutes, the concentration of the hydrochloric acid solution is 0.01-1 mol/L, and/or the aminosilane coupling agent is one or more of 3-aminopropyl triethoxysilane (APTES), 3-aminopropyl trimethoxysilane (APTMS) and N- (2-aminoethyl) -3-aminopropyl trimethoxysilane (DAMO), the mass percent of the aminosilane coupling agent in a methanol solution containing the aminosilane coupling agent is 0.1-wt% to 1 wt%, the soaking time in the methanol solution containing the aminosilane coupling agent is 30-120 minutes, and/or the solute of the metal ion solution is one or more of Zn(NO 3 ) 2 ·6H 2 O、Co(NO 3 ) 2 ·6H 2 O、ZrCl 4 、ZrOCl 2 ·8H 2 O and Al (NO 3 ) 3 ·9H 2 O), the solvent of the metal ion solution is one or more of DMF, the solvent of the metal ion solution is one or more of 3-7% and/or the 3% of the solvent of 3-3% and/or the 3% of the solvent of the 3-dimethyl benzene solution is 0.1-72%, the mass percent of the solvent is 3-3% and/or the solvent of the 3% is 3% and/or the solvent of the solvent is 3% and/or the solvent is 3% of the solvent is 3 and/or more of the solvent is 3 and/or 3 is 3, the volume percentage of the methanol in the methanol aqueous solution is 10% -90%.
4. The MOF-supported PET-based separator composite ether-cyano high voltage electrolyte type gel electrolyte of claim 3 wherein the organic ligands further comprise fluorine-containing organic ligands and/or sulfonic acid group-containing organic ligands.
5. The MOF-supported PET-based separator composite ether-cyano high-pressure electrolyte gel electrolyte of claim 1, wherein the mass percentage of the polymer in the ether-cyano high-pressure electrolyte gel precursor is 2% -10%, the mass percentage of the ether-cyano bifunctional high-pressure electrolyte is 2% -20%, the mass percentage of the lithium salt is 1% -10%, and/or the ether-cyano bifunctional high-pressure electrolyte is one or more of 2- (2-methoxyethoxy) acetonitrile, 2- [2- (2-methoxyethoxy) ethoxy ] acetonitrile and 2- [2- (2-methoxyethoxy) ethoxy ] acetonitrile, and/or the polymer is one or more of polyethylene oxide, polyvinylidene fluoride and polyvinylidene fluoride-hexafluoropropylene copolymer, and/or the lithium salt is one or more of lithium bis (trifluoromethylsulfonyl) imide, lithium bis (oxalyl) borate, lithium difluoro (oxalyl) borate, lithium hexafluorophosphate and lithium perchlorate.
6. The MOF-supported PET-based separator composite ether-cyano high-voltage electrolyte gel electrolyte of claim 5, wherein the ether-cyano difunctional high-voltage electrolyte is 2- [2- (2-methoxyethoxy) ethoxy ] acetonitrile and/or 2- [2- (2- (2-methoxyethoxy) ethoxy ] acetonitrile.
7. The MOF-loaded PET-based separator composite ether-cyano high voltage electrolyte type gel electrolyte of claim 5 wherein the polymer is polyvinylidene fluoride and/or polyvinylidene fluoride-hexafluoropropylene copolymer.
8. A method for preparing the MOF-supported PET-based separator composite ether-cyano high-voltage electrolyte type gel electrolyte according to any one of claims 1 to 7, comprising: providing a MOF-loaded PET-based separator; The polymer, the ether-cyano dual-function high-voltage electrolyte and the lithium salt are dissolved in an organic solvent together to obtain a uniform and transparent ether-cyano high-voltage electrolyte gel precursor; And placing the MOF-loaded PET-based diaphragm in a polytetrafluoroethylene mould, pouring the ether-cyano high-pressure electrolyte gel precursor liquid on the MOF-loaded PET-based diaphragm, and carrying out vacuum drying to obtain the MOF-loaded PET-based diaphragm composite ether-cyano high-pressure electrolyte gel electrolyte.
9. The method according to claim 8, wherein the organic solvent is N, N-Dimethylformamide (DMF) or acetonitrile, and/or the vacuum drying temperature is 50-70 ℃ and the vacuum drying time is 8-48 hours.
10. A lithium ion battery comprising the MOF-loaded PET-based separator composite ether-cyano high-voltage electrolyte gel electrolyte of any one of claims 1-7.

Description

MOF-loaded PET-based diaphragm composite ether-cyano high-voltage electrolyte type gel electrolyte and preparation method and application thereof Technical Field The invention belongs to the technical field of gel polymer electrolytes, and particularly relates to a MOF-loaded PET-based diaphragm composite ether-cyano high-voltage electrolyte type gel electrolyte, and a preparation method and application thereof. Background Lithium ion batteries have become the power source technology of choice in the fields of portable electronic equipment, electric automobiles, energy storage systems and the like because of the characteristics of high energy density, long cycle life, low self-discharge rate and the like. However, the theoretical specific capacity of conventional graphite cathodes is limited (about 372 mAh/g), and it is difficult to meet the increasing demand for high energy density. Lithium metal anodes are considered ideal anode materials for next generation high specific energy batteries due to their extremely high theoretical specific capacity (mAh/g) and lowest reduction potential (-3.04V vs. Standard hydrogen electrode). The high-capacity anode material such as nickel-rich layered oxide LiNi 0.8Co0.1Mn0.1O2 (NCM 811) can be matched with the high-capacity anode material, so that the energy density of the battery can be further improved. However, the system still faces two key challenges, namely, firstly, lithium dendrites are easy to form in the deposition/stripping process of a lithium metal anode, if the mechanical strength of an electrolyte is insufficient, dendrites can be penetrated to cause internal short circuit of a battery, and secondly, a traditional carbonate-based electrolyte is easy to be oxidized and decomposed under high voltage (> 4.3V vs. Li +/Li), so that the interface stability is poor, the capacity is fast attenuated and the battery is invalid. To improve the mechanical strength of the electrolyte, a separator is often introduced as a supporting skeleton. The PET non-woven fabric (polyethylene terephthalate, PET) has good thermal stability, and is a potential diaphragm material. However, the intrinsic pore size of the PET nonwoven fabric is large, the porosity is high, and in order to ensure sufficient mechanical strength to resist dendrite penetration, the thickness is often required to be increased, and the volume energy density of the battery is affected by the increase of the thickness. One currently viable approach is to improve the overall performance of PET nonwoven fabric-based polymer electrolytes by introducing newly developed oxidation-resistant solvents or functional additives into the electrolytes, especially high-voltage electrolytes, whereas ether solvents commonly used in electrolytes, although having excellent lithium ion transport capacity, generally have oxidation resistance below 4.0V, which is difficult to match with high-voltage anodes. The strong electron attraction capability of the cyano (-C≡N) functional group can effectively inhibit the loss of the ether oxygen lone pair electrons, thereby improving the oxidation stability, but affecting the compatibility with the anode, the overall ion conductivity of the electrolyte and the lithium ion migration number. The previous research results show (202411831326.9' preparation method and application of PET reinforced double-crosslinked polyionic liquid composite solid electrolyte), through improving the composition aspects of PET non-woven fabrics and polymer electrolytes at the same time, a PET non-woven fabric-based solid polymer electrolyte film with thinner thickness, higher mechanical strength, higher porosity, better ionic conductivity and higher electrochemical stability window can be prepared, however, the process relies on the electrolyte precursor liquid taking nano zinc oxide modified and functionalized alkenyl ionic liquid as a main body for the composite PET non-woven fabric, chemical bonding of the non-woven fabric and the ionic liquid is realized by utilizing thermal polymerization, then self-crosslinking of the ionic liquid is realized by photopolymerization, the product performance is limited by raw material selection and step-by-step crosslinking polymerization, and the obtained PET non-woven fabric-based solid polymer electrolyte film still cannot solve the compromise of high ionic conductivity and high lithium ion migration number. The development of a composite gel electrolyte system which can inhibit the growth of lithium dendrites, resist high-voltage oxidation, has excellent interface stability and combines high ion conductivity and high lithium ion migration number has important significance for promoting the development of high-energy-density lithium metal batteries. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a MOF-loaded PET-based diaphragm composite ether-cyano high-voltage electrolyte type gel electrolyte, and a preparation method and applicat