CN-122025789-A - Porphyrin-based 2D/2D-MOF/COF nanosheet heterojunction-based gel electrolyte, preparation method thereof and sodium ion battery

CN122025789ACN 122025789 ACN122025789 ACN 122025789ACN-122025789-A

Abstract

The invention discloses a sodium ion gel electrolyte based on porphyrin-based 2D/2D-MOF/COF nanosheet heterojunction, and belongs to the technical field of sodium ion battery electrolytes. The gel electrolyte is prepared by taking porphyrin-based 2D/2D-MOF/COF nanosheet heterojunction as a functional core, and compounding a sodium ion source, a gel matrix and a solvent. The heterojunction has MOFs high active sites and COFs stable porous structures, a charge transmission channel, a surface ion type construction unit and rich nitrogen sites are formed at the interface of the heterojunction, the efficient dissociation and directional migration of the heterojunction are promoted by the aid of the heterojunction and sodium ions, the space constraint effect of a gel network can inhibit the aggregation and dendrite growth of the sodium ions, and the structural stability and interface compatibility of an electrolyte are improved. The gel electrolyte disclosed by the invention has high room-temperature ion conductivity and excellent cycling stability, is applied to a sodium ion battery, can obviously improve the rate performance, the cycle life and the safety performance of the battery, and effectively solves the technical bottlenecks of low ion conduction efficiency and poor interface contact of the conventional sodium ion gel electrolyte.

Inventors

LI CHUNLI
WU JIAOJIAO
JIANG RONG
WANG RUIRUI
LI YIXIAO

Assignees

北京化工大学

Dates

Publication Date: 20260512
Application Date: 20260319

Claims (10)

1. The preparation method of the sodium ion gel electrolyte based on porphyrin-based 2D/2D-MOF/COF heterojunction nanosheets is characterized by comprising the following steps: S1, porphyrin-based 2D-MOFs nano-sheets; S2, in-situ growing a 2D-COFs nano sheet layer on the surface of the porphyrin-based 2D-MOFs nano sheet to obtain a porphyrin-based 2D/2D-MOF/COF heterojunction nano sheet; S3, mixing the porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheet, a sodium ion source and a gel matrix to obtain the sodium ion gel electrolyte based on the porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheet.
2. The method for preparing the sodium ion gel electrolyte based on the porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheet according to claim 1, wherein in the step S2, a mixed solution of cationic triaminoguanidine hydrochloride and HATN-CHO is prepared, then the porphyrin-based 2D-MOFs nano-sheet is added into the mixed solution, and the porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheet is prepared through Schiff base condensation reaction.
3. The preparation method of the sodium ion gel electrolyte based on the porphyrin-based 2D/2D-MOF/COF heterojunction nanosheets is characterized in that the molar ratio of cationic triaminoguanidine hydrochloride to HATN-CHO in the mixed solution is (1.3-2.2): 1-1.5, the solvent of the mixed solution is a mixed solution of DMF and ethanol, the volume ratio of DMF and ethanol in the mixed solution is (1-3): 1-2), the reaction temperature in the step S2 is 45-75 ℃ and the reaction time is 8-22 h, and the porphyrin-based 2D/2D-MOF/COF heterojunction nanosheets are obtained through centrifugal separation and vacuum drying after the reaction is finished; preferably, the vacuum drying temperature is 60-80 ℃ and the duration is 12-24 hours.
4. The method for preparing the sodium ion gel electrolyte based on the porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheet according to any one of claims 1 to 3, wherein the building block of the porphyrin-based 2D-MOFs nano-sheet prepared in the step S1 is a porphyrin compound with a four-connection conjugated structure and a metal complex thereof, and the coordination center metal ion is at least one selected from Cu 2+ 、Ni 2+ 、Co 2+ and Mn 2+ .
5. The preparation method of the sodium ion gel electrolyte based on the porphyrin-based 2D/2D-MOF/COF heterojunction nanosheets, according to claim 4, is characterized in that in the step S1, under the assistance of a surfactant, a porphyrin building unit and a metal salt undergo a coordination reaction to obtain the porphyrin-based 2D-MOFs nanosheets, wherein the porphyrin building unit is selected from (5, 10,15, 20-tetra (4-carboxyphenyl) porphyrin), and the metal salt is selected from one or more of copper nitrate, nickel nitrate, cobalt nitrate and manganese nitrate; Preferably, the porphyrin building block is 5,10,15, 20-tetra (4-carboxyphenyl) porphyrin.
6. The method for preparing a sodium ion gel electrolyte based on porphyrin-based 2D/2D-MOF/COF heterojunction nanosheets according to any one of claims 1 to 5, wherein in step S3, a sodium ion source is added into a second solvent, stirring is performed for 2h to 4h at a temperature of 40 ℃ to 60 ℃ to obtain a sodium ion solution, then porphyrin-based 2D/2D-MOF/COF heterojunction nanosheets are added into the sodium ion solution, ultrasonic dispersion is performed for 0.5h to 2h to obtain a dispersion liquid, finally a gel matrix is added into the dispersion liquid, stirring is performed for 3h to 6h at a temperature of 50 ℃ to 80 ℃, and then standing is performed for 6h to 12h to room temperature to obtain the sodium ion gel electrolyte based on porphyrin-based 2D/2D-MOF/COF heterojunction nanosheets.
7. The method for preparing a sodium ion gel electrolyte based on porphyrin-based 2D/2D-MOF/COF heterojunction nanoplatelets as defined in claim 6, wherein in step S3, the ratio of the sodium ion source, the gel matrix and the second solvent is as follows: 6-18 parts of porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheets; 12-30 parts of sodium ion source; 4-12 parts of gel matrix; 45-75 parts of a second solvent.
8. The preparation method of the sodium ion gel electrolyte based on the porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheet, which is disclosed in claim 6, is characterized in that in the step S3, a sodium ion source is selected from one or more of NaTFSI and NaPF 6 、NaFSI、NaClO 4 , a gel matrix is selected from one or more of polyacrylamide, sodium alginate, gelatin and polyethylene glycol diacrylate, and a second solvent is selected from one or more of Propylene Carbonate (PC), ethylene Carbonate (EC), N-Dimethylformamide (DMF) and ethanol.
9. A sodium ion gel electrolyte based on porphyrin-based 2D/2D-MOF/COF heterojunction nanoplatelets, characterized in that it is prepared by the preparation method according to any one of claims 1 to 8.
10. The sodium ion battery is characterized by comprising a positive electrode, a negative electrode and the sodium ion gel electrolyte based on the porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheet, wherein the thickness of the porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheet in the gel electrolyte is 3-35nm, the transverse dimension of the porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheet is 120-900nm, and the sodium ion gel electrolyte based on the porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheet is clamped between the positive electrode and the negative electrode to jointly form a sandwich structure.

Description

Porphyrin-based 2D/2D-MOF/COF nanosheet heterojunction-based gel electrolyte, preparation method thereof and sodium ion battery Technical Field The invention belongs to the technical field of sodium ion battery electrolyte, and particularly relates to a porphyrin-based 2D/2D-MOF/COF nanosheet heterojunction-based gel electrolyte, a preparation method thereof and a sodium ion battery. Background The sodium ion battery has wide application prospect in the fields of large-scale energy storage, low-speed electric automobiles and the like due to the advantages of abundant sodium resource reserves, wide distribution, low cost and the like. The electrolyte is used as the 'blood' of the sodium ion battery and plays a key role in sodium ion transmission and charge conduction, and the performance of the electrolyte directly determines the energy density, the cycle life, the multiplying power performance and the safety performance of the battery. Currently, sodium ion battery electrolytes mainly include liquid electrolytes, solid electrolytes, and gel electrolytes. The liquid electrolyte has high ionic conductivity, but has potential safety hazards such as liquid leakage, inflammability, sodium ion dendrite growth and the like, the solid electrolyte has excellent safety, but has low ionic conduction efficiency and large interface contact resistance, and is difficult to meet the practical application requirements, and the gel electrolyte combines the advantages of high ionic conductivity of the liquid electrolyte and good stability of the solid electrolyte, so that the gel electrolyte becomes a research hot spot. However, the existing gel electrolyte mostly adopts the traditional polymer or the simple inorganic filler as the matrix, and has the problems of low dissociation efficiency of sodium ions, discontinuous transmission channels, poor interface compatibility and the like, so that the capacity attenuation is fast, the multiplying power performance is poor in the battery circulation process, the gel electrolyte is easy to crystallize and collapse in a low-temperature environment, the low-temperature performance of the battery adopting the gel electrolyte is poor, and the industrialization progress of the sodium ion battery is limited from different angles. The porphyrin-based 2D/2D-MOF/COF nanosheet heterojunction is a novel composite functional material, and has high catalytic activity of MOFs, and stable porous structure and adjustable functional groups of rich active sites and COFs. The unique 2D/2D heterojunction structure can construct a high-efficiency charge transmission channel, the surface ion type construction unit and rich nitrogen sites can generate electrostatic attraction and synergistic coordination with sodium ions to promote dissociation and migration of the sodium ions, and meanwhile, the rigid conjugated plane structure can enhance the mechanical property of electrolyte. The method is applied to the sodium ion gel electrolyte, is hopeful to construct a high-efficiency sodium ion transmission channel through the cooperative optimization of material structure and performance, improves the interface compatibility of the electrolyte and an electrode, and provides a new way for developing a high-performance sodium ion battery. The present invention has been made in view of this. Disclosure of Invention Aiming at the problems in the prior art, the invention provides a preparation method of a sodium ion gel electrolyte based on porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheets, which is characterized in that porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheets with unique 2D/2D heterojunction structures are introduced into the gel electrolyte, so that a high-efficiency charge transmission channel is constructed in the gel electrolyte, the interface contact state is improved, and the performance of a sodium ion battery can be effectively improved. The invention also provides the sodium ion gel electrolyte based on the porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheet prepared by the method. The invention further provides a sodium ion battery with the sodium ion gel electrolyte. In order to achieve the above object, the first aspect of the present invention provides a preparation method of a sodium ion gel electrolyte based on porphyrin-based 2D/2D-MOF/COF heterojunction nanosheets, comprising the steps of: S1, preparing a porphyrin-based 2D-MOFs nano-sheet; S2, in-situ growing a 2D-COFs nano sheet layer on the surface of the porphyrin-based 2D-MOFs nano sheet to obtain a porphyrin-based 2D/2D-MOF/COF heterojunction nano sheet; S3, mixing the porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheet, a sodium ion source and a gel matrix to obtain the sodium ion gel electrolyte based on the porphyrin-based 2D/2D-MOF/COF heterojunction nano-sheet. Further, in step S2, a mixed solution of cationic triaminoguanidine hydrochloride and HATN-CHO is prepared, then the porphyrin-based 2D-MOFs nano-s