阅读说明：本技术 导电聚苯胺@芳纶纳米纤维复合薄膜材料及其制备方法 (Conductive polyaniline @ aramid nanofiber composite film material and preparation method thereof ) 是由 贾红兵 尹清 张旭敏 陆少杰 吉庆敏 詹小婉 麦伟泉 王艺凝 王经逸 于 2019-10-20 设计创作，主要内容包括：本发明公开了一种导电聚苯胺@芳纶纳米纤维复合薄膜材料及其制备方法。所述方法以DMSO/KOH体系配制的2～10mg/mL的芳纶纳米纤维溶液制得的芳纶纳米纤维薄膜为基底材料,将其浸泡在新鲜配制的苯胺单体浓度为0.03～1.5M,苯胺/(NH<Sub>4</Sub>)S<Sub>2</Sub>O<Sub>8</Sub>的摩尔比为1.0～2.0的聚合前驱体溶液中,经苯胺自聚合,得到导电聚苯胺@芳纶纳米纤维复合薄膜。本发明以芳纶纳米纤维薄膜为力学支撑,以导电聚苯胺纳米结构作为集流器及电化学活性功能组分,利用芳纶纳米纤维薄膜与导电聚苯胺的协同增强作用,制得具有高机械强度、高比电容、高韧性的柔性自支撑电极材料。(The invention discloses a conductive polyaniline @ aramid nanofiber composite film material and a preparation method thereof. The method takes an aramid nano-fiber film prepared from an aramid nano-fiber solution of 2-10 mg/mL prepared by a DMSO/KOH system as a substrate material, and the aramid nano-fiber film is soaked in a freshly prepared aniline monomer with the concentration of 0.03-1.5M, wherein the aniline/(NH) is 4 )S 2 O 8 In the polymerization precursor solution with the molar ratio of 1.0-2.0, the conductive material is obtained by self-polymerization of anilinePolyaniline @ aramid nanofiber composite film. The invention takes the aramid fiber nanofiber film as a mechanical support, takes the conductive polyaniline nanostructure as a current collector and an electrochemical active functional component, and utilizes the synergistic enhancement effect of the aramid fiber nanofiber film and the conductive polyaniline to prepare the flexible self-supporting electrode material with high mechanical strength, high specific capacitance and high toughness.)

1. The preparation method of the conductive polyaniline @ aramid nanofiber composite film material is characterized by comprising the following specific steps of:

(1) dissolving PPTA spinning fibers by using a DMSO/KOH system to prepare 2-10 mg/mL aramid nano fiber solution;

(2) adding water into the aramid nano-fiber solution, stirring at room temperature, and aging and defoaming the obtained mixed gel system;

(3) assembling the mixed system obtained in the step (2) into an aramid nanofiber gel film by adopting a vacuum filtration method;

(4) washing the aramid nanofiber gel film, removing redundant DMSO and potassium ions, and drying to obtain the aramid nanofiber film;

(5) based on aniline monomer and (NH)₄)₂S₂O₈The molar ratio of (A) to (B) is 1.0-2.0, and aniline monomer is added into HClO₄Stirring the solution until dissolved, and adding precooled (NH)₄)₂S₂O₈Obtaining a polymerization precursor solution with the aniline concentration of 0.03-1.5M;

(6) and (2) immediately soaking the aramid nano-fiber film in a polymerization precursor solution to carry out aniline self-polymerization, taking out the film after polymerization is finished, washing and drying to obtain the conductive polyaniline @ aramid nano-fiber composite film.

2. The preparation method according to claim 1, wherein in the step (1), the dissolving time is two weeks, the dissolving temperature is room temperature, and the average size of the aramid nanofibers is as follows: the diameter is 30-40 nm and the length is 5-10 μm.

3. The preparation method according to claim 1, wherein in the step (2), 125-200 mL of water is added to each 100mL of the aramid nanofiber solution; stirring for 2-4 h at room temperature; the aging and defoaming time is more than 2 h.

4. The preparation method according to claim 1, wherein in the step (3), the suction filtration device adopts a sand core funnel to prepare the microporous filtration membrane with the diameter of 47mm, and the vacuum suction filtration pressure is-0.1 MPa.

5. The preparation method according to claim 1, wherein in the step (4), the washing method comprises the steps of dropwise adding 100-200 mL of water on the surface of the aramid nano-fiber gel film, and then carrying out vacuum filtration to remove redundant DMSO and potassium ions; the drying procedure is drying at room temperature for 24-48 h, and then vacuum drying at 50-60 ℃ for 20-24 h.

6. The method according to claim 1, wherein in the step (5), HClO is used₄The concentration of the solution is 1M, the temperature is controlled to be 4 ℃ by adopting ice bath assistance in the aniline monomer dissolving process, and the stirring time is 0.5-1 h.

7. The preparation method according to claim 1, wherein in the step (6), the size of the aramid nanofiber film is 1 x 1cm²(ii) a The polymerization time is 2-4 h; the washing step was carried out using 1M HClO₄Sequentially washing the solution, ethanol and water; the drying procedure is drying at room temperature for 12-24 h.

8. The preparation method of claim 1, wherein in the step (6), the loading amount of polyaniline in the conductive polyaniline @ aramid nanofiber composite film is 1.6-7.7 wt.%.

9. The conductive polyaniline @ aramid nanofiber composite film material prepared by the preparation method according to any one of claims 1 to 8.

10. The conductive polyaniline @ aramid nanofiber composite film material as claimed in claim 9, as a flexible self-supporting electrode material, in application to the preparation of a supercapacitor.

Technical Field

The invention belongs to the technical field of electrode material preparation, and relates to a conductive polyaniline @ aramid nanofiber composite film material and a preparation method thereof.

Background

The super capacitor is a novel energy storage device between a battery and a traditional capacitor, and has wide application in the fields of new energy power generation systems, distributed energy storage systems, new energy automobiles, aerospace equipment and the like. With the development of commercialization of portable electronic devices and hybrid electric vehicles, higher practical requirements are being placed on electrode materials of supercapacitors. At present, most of electrode materials adopt a traditional coating process, namely, electrochemical active components, a polymer adhesive, a conductive agent and a dispersing solvent are uniformly mixed according to a certain proportion and coated on a metal current collector. However, the inherent high density and rigidity of the metal current collector cannot meet the requirements of the new electronic device for flexibility, convenience and wearability of the energy storage device. Moreover, the adhesion between the electrode material and the metal current collector is often poor, and the electrode material is cracked after being bent for several times, so that the electrode material falls off from the current collector, and the electrochemical performance of the supercapacitor is reduced. More importantly, the electrode materials are difficult to use in actual operating environments such as bending, folding and stretching, so that research on the self-supporting flexible electrode materials with high mechanical strength and high electrochemical performance becomes a research hotspot in the field of new energy at present.

Poly-p-phenylene terephthamide (PPTA) is a high-performance para-aramid fiber with a basic repeating unit of- [ -CO-C₆H₄-CONH-C₆H₄NH-]-. The macroscopic aramid fiber yarn has the advantages of high strength, high modulus, high temperature resistance, chemical corrosion resistance, strong flame retardance, fatigue resistance, strong stability and the like. The para-aramid fiber is dissolved in dimethyl sulfoxide to obtain the aramid nanofiber (ACS nano,2011,5(9): 6945-. The film material assembled by the aramid nano-fiber has excellent mechanical strength and can be used as an excellent carrier of a self-supporting flexible electrode. For example, aramid nanofibers are compounded with conductive polythiophene to form a flexible electrode material (J.Mater.chem.A., 2016,4: 17324-. However, the electrode material is prepared by means of liquid phase blending, and poor interfacial compatibility among components results in low mechanical strength (76.4MPa) and low mass specific capacitance (111.5F/g).

Polyaniline (PANI), one of the most commonly used conductive polymers, has wide applications in the field of supercapacitor electrode materials. Chinese patent application 201811177417.X adopts in-situ polymerization mode to assemble polyaniline on the substrate of cellulose film to prepare the conductive composite film with certain mechanical strength. However, this method has the following problems: the cellulose film is a porous structure, the mechanical strength and the elongation at break of the cellulose film are low, and particularly after the polyaniline is assembled, the mechanical property of the composite material is weakened; the traditional chemical oxidative polymerization method cannot regulate and control the polyaniline nano-structure, and the prepared polyaniline is simply wrapped on the surface of cellulose in a granular form and cannot play a role in enhancing the electrochemical performance of the material by the nano-structure. Therefore, the assembly of polyaniline nanostructures into self-supporting electrode materials with high strength and high specific capacitance remains a great challenge.

Disclosure of Invention

The invention aims to provide a conductive polyaniline @ aramid nanofiber composite film material with high mechanical strength, high toughness and high specific capacitance and a preparation method thereof. The invention takes the aramid nano-fiber with high mechanical strength and high flexibility as a substrate material, and is compounded with conductive polyaniline to prepare the electrode material with high mechanical strength, high toughness and high specific capacitance, and the electrode material can be used as a flexible self-supporting electrode material.

The technical solution for realizing the purpose of the invention is as follows:

the preparation method of the conductive polyaniline @ aramid nanofiber composite film material comprises the following specific steps:

(1) dissolving PPTA spinning fibers by using a dimethyl sulfoxide (DMSO)/KOH system to prepare 2-10 mg/mL aramid nano fiber solution;

(2) adding water into the aramid nano-fiber solution, stirring at room temperature, and aging and defoaming the obtained mixed gel system;

(3) assembling the mixed system obtained in the step (2) into an aramid nanofiber gel film by adopting a vacuum filtration method;

(4) washing the aramid nanofiber gel film, removing redundant DMSO and potassium ions, and drying to obtain the aramid nanofiber film;

(5) based on aniline monomer and (NH)₄)₂S₂O₈The molar ratio of (A) to (B) is 1.0-2.0, and aniline monomer is added into HClO₄Stirring the solution until dissolved, and adding precooled (NH)₄)₂S₂O₈Obtaining a polymerization precursor solution with the aniline concentration of 0.03-1.5M;

(6) and (2) immediately soaking the aramid nano-fiber film in a polymerization precursor solution to carry out aniline self-polymerization, taking out the film after polymerization is finished, washing and drying to obtain the conductive polyaniline @ aramid nano-fiber composite film.

Further, in the step (1), the dissolving time is two weeks, the dissolving temperature is room temperature, and the average size of the aramid nanofibers is as follows: the diameter is 30-40 nm and the length is 5-10 μm.

Further, in the step (2), 125-200 mL of water is added into every 100mL of aramid nano-fiber solution; stirring for 2-4 h at room temperature; the aging and defoaming time is more than 2 h.

Further, in the step (3), a sand core funnel is adopted by the suction filtration device to prepare a microporous filter membrane with the diameter of 47mm, and the vacuum suction filtration pressure is-0.1 MPa.

Further, in the step (4), the washing method comprises the steps of dripping 100-200 mL of water on the surface of the aramid nano-fiber gel film, and then carrying out vacuum filtration to remove redundant DMSO and potassium ions; the drying procedure is drying at room temperature for 24-48 h, and then vacuum drying at 50-60 ℃ for 20-24 h.

Further, in the step (5), HClO₄The concentration of the solution is 1M, the temperature is controlled to be 4 ℃ by adopting ice bath assistance in the aniline monomer dissolving process, so that aniline prepolymerization is prevented, and the stirring time is 0.5-1 h.

Further, in the step (6), the size of the aramid nano-fiber film is 1 × 1cm²(ii) a The polymerization time is 2-4 h; the washing step was carried out using 1M HClO₄Sequentially washing the solution, ethanol and water; the drying procedure is drying at room temperature for 12-24 h.

Further, in the step (6), the loading amount of polyaniline in the conductive polyaniline @ aramid nanofiber composite film is 1.6-7.7 wt.%.

Compared with the prior art, the invention has the following advantages:

(1) the aramid fiber nanofiber film is used as a mechanical support, the conductive polyaniline nanostructure is used as a current collector and an electrochemical active functional component, and the synergistic enhancement effect of the aramid fiber nanofiber film and the conductive polyaniline is utilized to prepare the flexible self-supporting electrode material with high mechanical strength, high specific capacitance and high toughness.

(2) The relative proportion of the polyaniline nano-array and the polyaniline nano-particles in the aramid fiber nanofiber surface coating is controlled by controlling the polymerization process parameters of aniline on the surface of the aramid fiber nanofiber film, the synergistic effect of polyaniline components is exerted, and the mechanical strength and the specific capacitance of the electrode material are further improved. When the mass fraction of the polyaniline is 4.6 wt.%, the mechanical strength of the obtained film electrode material reaches 233.3MPa, and the specific capacitance can reach 441F/g under the charge-discharge current density of 1A/g. The specific capacitance retention rate of the assembled symmetrical all-solid-state supercapacitor device in the bent and twisted states is 95% and 98%.

Drawings

Fig. 1 is a schematic diagram of a preparation process of a conductive polyaniline @ aramid nanofiber composite film material.

Fig. 2 is an SEM image of the conductive polyaniline @ aramid nanofiber composite film prepared in example 1.

Fig. 3 is a stress-strain curve diagram of the conductive polyaniline @ aramid nanofiber composite film prepared in examples 1-4 and the aramid nanofiber prepared in comparative example 1.

FIG. 4 is a cyclic voltammogram of the conductive polyaniline @ aramid nanofiber composite films prepared in examples 1-4 and the aramid nanofibers prepared in comparative example 1.

Detailed Description

The invention is further illustrated by the following specific examples, comparative examples and figures.