CN-122025429-A - Porous MXene composite membrane and preparation method and application thereof

Abstract

The invention belongs to the technical field of nano materials and electrochemical energy storage, and particularly relates to a porous MXene composite membrane, a preparation method and application thereof. The porous MXene composite membrane modified by the liquid organic matters is obtained by introducing a nano porous structure on an MXene nano sheet through oxidation etching, forming a porous MXene membrane with a self-supporting structure on a substrate through vacuum suction filtration, immersing the self-supporting porous MXene membrane in the liquid organic matters, and filling the liquid organic matters into the nano sheet layers and nano holes of the porous MXene membrane. Based on the porous nano-sheet structure and the filling of liquid organic matters, the self-supporting MXene composite membrane has more excellent ion storage capacity and ion transmission performance, so that the electrochemical performance of the self-supporting MXene composite membrane serving as a self-supporting electrode is improved. The preparation process is simple, the conditions are mild, and a new idea is provided for the design of high-performance electrode materials.

Inventors

• SUN YUE
• LI XIANG
• ZHU ZHONGHUA
• JIANG SHILIANG

Assignees

• 淮北师范大学

Dates

Publication Date

20260512

Application Date

20260317

Claims (10)

1. 1. The porous MXene composite membrane is characterized in that a self-supporting porous MXene membrane is formed on a substrate by utilizing porous MXene nano sheets, and the self-supporting porous MXene membrane is soaked in liquid organic matters, so that the liquid organic matters are filled between nano sheet layers and in nano holes of the porous MXene membrane; The liquid organic matter is at least one of dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate and fluoroethylene carbonate.
2. 2. The porous MXene composite membrane of claim 1, wherein the liquid organic matter is dimethyl carbonate and ethyl methyl carbonate, and the volume ratio of the dimethyl carbonate to the ethyl methyl carbonate is 1-9:3.
3. 3. The porous MXene composite membrane of claim 1 or 2, in which the porous MXene nanoplatelets are oxidized etched with an oxidizing agent to form interconnected nanoporous structures on the MXene nanoplatelets.
4. 4. The porous MXene composite membrane according to claim 3, wherein the MXene nano-sheets are single-layer Ti 3 C 2 T x nano-sheets, the length of the single-layer Ti 3 C 2 T x nano-sheets is 150 nm-700 nm, the pore diameter of the nano-pores is 1 nm-20 nm, and the thickness of the porous MXene composite membrane is 4 μm-30 μm.
5. 5. A method of preparing a porous MXene composite membrane according to claim 3 comprising the steps of: Mixing the MXene suspension with an oxidant, and carrying out oxidation etching on the MXene nano-sheets in the MXene suspension to form mutually communicated nano-porous structures on the MXene nano-sheets so as to obtain porous MXene nano-sheets; Soaking the self-supporting porous MXene film in a liquid organic substance to fill the liquid organic substance into the nano-sheet layers and the nano holes of the porous MXene film, thereby obtaining the porous MXene composite film.
6. 6. The method of producing a porous MXene composite membrane according to claim 5, wherein the MXene suspension is an aqueous solution of MXene nanoplatelets, and the concentration of the MXene suspension is 2mg/mL.
7. 7. The method for preparing the porous MXene composite membrane according to claim 6, wherein the volume ratio of the MXene suspension to the oxidant is 4000:1-6, the mass concentration of the oxidant is 30wt%, and the oxidant is hydrogen peroxide or sulfuric acid.
8. 8. The method for preparing a porous MXene composite film according to claim 5, wherein the temperature of the oxidation etching is 25-60 ℃ for 20-60 min.
9. 9. The method of producing a porous MXene composite film according to claim 5, wherein the substrate is a polycarbonate film or a mixed cellulose film.
10. 10. Use of a porous MXene composite membrane as an electrode material in a supercapacitor, characterized in that the porous MXene composite membrane is the porous MXene composite membrane of claim 3.

Description

Porous MXene composite membrane and preparation method and application thereof Technical Field The invention belongs to the technical field of nano materials and electrochemical energy storage, and particularly relates to a porous MXene composite membrane, a preparation method and application thereof. Background Electrochemical energy storage devices include both rechargeable batteries and supercapacitors. The super capacitor is used as an innovative electrochemical energy storage technology, has the advantages of good flexibility, high power density, ultra-long cycle life, good multiplying power characteristic, excellent cycle stability, high safety and the like, and is widely applied to the energy fields of portable electronic equipment, wearable electronic products, new energy automobile kinetic energy recovery, power grids and the like. Despite the advantages of supercapacitors, the relatively low energy density limits the wide range of applications for supercapacitors. In supercapacitors, the electrode material is its core component, and designing an electrode material with better quality performance is a key challenge faced in the art. Two-dimensional nanomaterials are an important class of energy storage materials, such as graphene, graphite alkyne, transition metal disulfide, and the like, and are considered to be extremely potential supercapacitor electrode materials. The transition metal carbon/nitride (MXene) is an emerging inorganic two-dimensional nanomaterial, has the advantages of high mechanical strength, excellent metal conductivity, good surface hydrophilicity, adjustable interlayer spacing and the like, and can be used as an electrode material of a supercapacitor. The self-supporting film constructed based on the MXene nano-sheet has good flexibility and mechanical strength, and can be directly used as an electrode. However, the existing self-supporting MXene film has a serious self-stacking phenomenon between sheets, and the stacking causes the interlayer spacing of the film to be reduced, the specific surface area to be reduced, so that the electrochemically active space available for ion storage is narrowed. This directly limits the specific capacitance and energy density of the MXene membrane electrode, which is a critical technical problem that limits its high performance applications. Disclosure of Invention The invention provides a porous MXene composite membrane and a preparation method and application thereof, aiming at overcoming the defects of small layer spacing, limited ion storage space and insufficient electrochemical performance of the existing self-supporting MXene membrane caused by sheet stacking. According to the invention, the nano porous structure is introduced into the MXene nano sheet to form mutually communicated nano channels and pores, and liquid organic matters are filled between the sheets and in the nano pores of the MXene nano sheet, so that the tight stacking of the MXene sheets is structurally effectively inhibited, and the interlayer distance and the specific surface area of the porous MXene composite film are increased. Meanwhile, the nano holes provide additional ion transmission channels and electrochemical active sites, the liquid organic matters further optimize the ion storage space and promote the desolvation process of ions, and the electrochemical performance of the self-supporting porous MXene composite membrane serving as a super capacitor electrode material is remarkably improved. The invention provides a porous MXene composite membrane, which is prepared by forming a self-supporting porous MXene membrane on a substrate by utilizing porous MXene nano sheets, soaking the self-supporting porous MXene membrane in a liquid organic substance to fill the liquid organic substance between nano sheet layers and in nano holes of the porous MXene membrane, wherein the liquid organic substance is at least one of dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate and fluoroethylene carbonate. Preferably, the liquid organic material is selected from water-insoluble or sparingly soluble materials, has the ability to promote ion desolvation storage, and optimizes the interlayer spacing of the porous MXene nanoplatelets. The liquid organic matters are dimethyl carbonate and methyl ethyl carbonate, and the volume ratio of the dimethyl carbonate to the methyl ethyl carbonate is 1-9:3. More preferably, the volume ratio of dimethyl carbonate to ethylmethyl carbonate is 1:1. Preferably, the pores of the porous MXene nanoplatelets are irregular polygonal shaped pores. Preferably, the chemical formula of the MXene material is M n+1XnTx, wherein M is at least one of Ti, sc, V, cr, nb, mo, nd, zr, hf, Y, ta and W, X is C or N, and T x is a surface functional group such as-OH, -F or-O. More preferably, the MXene material is Ti 3C2Tx. Preferably, the porous MXene nanoplatelets are oxidized and etched by an oxidizing agent to form interconnected nanoporous stru