Preparation method and application of MOF-derived porous carbon composite electrode material

Abstract

The preparation method comprises the following steps: (1) dissolving a zinc salt in a mixed solvent of ethanol, DMF (Dimethyl Formamide), ammonia water and water, dropwise adding triazole, carrying out stirring reaction at room temperature for 5-10 hours, then carrying out aging treatment for 20-30 hours, obtaining a solid product, washing the solid product, and drying the solid product to obtain zinc-triazole MOF; (2) heating the zinc-triazole MOF to 800-850 DEG C under the protection of inert gas, calcining for 2-4 hours, cooling, washing to remove metal ions, and drying to obtain MOF-derived porous carbon; and (3) adding the MOF-derived porous carbon into an aniline hydrochloride solution, uniformly dispersing, adding an ammonium persulfate solution, stirring and reacting for 5-10 hours, and washing and drying a product to obtain the MOF-derived porous carbon composite electrode material. The MOF-derived porous carbon composite electrode material is used as a negative electrode material to prepare the supercapacitor, and the supercapacitor has very excellent electrochemical performance and cycling stability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of material chemistry and electrochemistry, and particularly relates to a MOF-derived porous carbon composite electrode material and application thereof in supercapacitors. BACKGROUND

[0002] With the development of new energy, energy storage has become a crucial focus. At present, among many energy storage devices, electrochemical energy storage devices are one of the most promising energy storage and conversion devices.

[0003] With the rapid development of new energy technology, energy storage has become a key bottleneck restricting its widespread application. Among many energy storage devices, electrochemical energy storage devices have become one of the most promising energy storage and conversion devices due to their high efficiency, convenience, fast charging and discharging, and other advantages. Among them, supercapacitors have become a research hotspot in the field of electrochemical energy storage due to their high power density, fast charging and discharging capability, and long cycle life.

[0004] Supercapacitors are mainly divided into three categories: electric double-layer capacitors (EDLCs), pseudocapacitors, and hybrid supercapacitors, according to the composition and working principle of electrode materials. However, traditional electric double-layer capacitors (EDLCs) have relatively high power density, but their energy density is relatively low, limiting their application in large-scale energy storage and other high-energy demand scenarios. At the same time, rechargeable metal batteries have high energy density, but have problems such as insufficient power density, poor rate performance, and unsatisfactory cycle life, which also make it difficult to meet the growing demand for high-performance energy storage. Therefore, designing high-performance electrode materials to effectively improve the energy density of supercapacitors has become a key issue in the field of electrochemical energy storage.

[0005] Asymmetric supercapacitors can balance power density and energy density to some extent by combining battery-type electrodes and capacitor-type electrodes, showing good application prospects. However, in this structure, compared to the high capacity of battery-type positive electrode materials, the specific capacitance of carbon negative electrode materials is usually low, which makes it difficult to match the high capacity of positive electrode materials, thereby limiting the improvement of the overall performance of asymmetric supercapacitors.

[0006] Therefore, finding a material with high specific capacity and compounding it with carbon materials to compensate for the low capacity of carbon materials is a highly potential strategy. Through the development of such composite materials, it is expected to significantly improve the energy density of asymmetric supercapacitors, thereby expanding their application range in the field of high-performance energy storage. SUMMARY

[0007] The present application aims to provide a MOF-derived porous carbon and a polyaniline-coated MOF-derived porous carbon composite material for use as an asymmetric supercapacitor negative electrode material, which has high power density and high cycle performance.

[0008] The technical scheme adopted by the present application is as follows:

[0009] A preparation method of a MOF-derived porous carbon composite electrode material, the method comprising the following steps:

[0010] (1) Dissolve a zinc salt in a mixed solvent of ethanol, DMF, ammonia water and water, add triazole dropwise, stir at room temperature for 5-10 h, and then perform aging treatment for 20-30 h to obtain a solid product, which is washed and dried to obtain a zinc-triazole MOF;

[0011] (2) Calcine the zinc-triazole MOF under inert gas protection at a temperature of 800-850℃ for 2-4 h, wash to remove metal ions after cooling, and dry to obtain a MOF-derived porous carbon;

[0012] (3) Add the MOF-derived porous carbon into an aniline hydrochloride solution, uniformly disperse, add an ammonium persulfate solution, stir for 5-10 h, and then wash and dry the product to obtain a MOF-derived porous carbon composite electrode material.

[0013] In the step (1), the zinc salt is a water-soluble zinc salt, such as zinc chloride, zinc acetate, etc., preferably zinc acetate.

[0014] The triazole is 1H-1,2,3-triazole.

[0015] In the mixed solvent, the volume ratio of water, ethanol, DMF (N,N-dimethylformamide), ammonia water is 3-3.5:2-2.2:2-2.2:0.8-1.2;

[0016] The mass concentration of the ammonia water is 25-28%.

[0017] The dropwise adding speed of the ammonia water is 0.004-0.01 mL / s.

[0018] The molar ratio of the zinc salt to triazole is 1:2.5-3.5.

[0019] The volume of the mixed solvent is 1-5 mL / mmol in terms of the amount of substance of the zinc salt.

[0020] The solid product can be sequentially washed with DMF, deionized water and ethanol.

[0021] The drying can be performed at a temperature of 60-70℃ for 20-30 h under vacuum.

[0022] In the step (2), the inert gas is preferably nitrogen or argon.

[0023] The step (2) is preferably calcined in a tube furnace.

[0024] The heating rate is preferably 2-10 ℃ / min, more preferably 5 ℃ / min.

[0025] In the step (2), the washing removes metal ions, which can be removed by washing with dilute hydrochloric acid, and then washing with deionized water.

[0026] The drying can be vacuum drying at 60-70 ℃ for 20-30 h.

[0027] In the step (3), the concentration of aniline in the aniline hydrochloride solution is 0.05-0.4 mol / L, preferably 0.1 mol / L.

[0028] The aniline hydrochloride solution is prepared by adding aniline to dilute hydrochloric acid, and the concentration of the dilute hydrochloric acid is 0.5-2 mol / L, preferably 1 mol / L.

[0029] The volume of the aniline hydrochloride solution is preferably 20-200 mL / g of the mass of the MOF-derived porous carbon.

[0030] The mass ratio of aniline to ammonium persulfate is 1:3-24, preferably 1:10-15.

[0031] The application also provides a MOF-derived porous carbon composite electrode material prepared by the above method. The MOF-derived porous carbon composite electrode material uses MOF-derived porous carbon as a carrier and is coated with polyaniline on the surface.

[0032] The application also provides the use of the MOF-derived porous carbon composite electrode material in supercapacitors.

[0033] Further, in the method of use, the MOF-derived porous carbon composite electrode material is used as a negative electrode material in an asymmetric supercapacitor.

[0034] The application also provides an asymmetric supercapacitor using the MOF-derived porous carbon composite electrode material as a negative electrode material.

[0035] The application synthesizes MOF as a precursor by taking 1H-1,2,3-triazole as a ligand, prepares MOF-derived porous carbon by pyrolysis of the MOF, and coats polyaniline on the MOF-derived porous carbon to form a porous carbon / conductive polymer composite material. Because the nitrogen content of the ligand triazole is high, a large amount of gas can be generated during pyrolysis, and porous carbon with rich pores is generated. Then, in-situ polymerization of aniline is performed on the porous carbon, and the aniline is coated on the surface of the porous carbon and in the pores generated during pyrolysis, to obtain a conductive polymer porous carbon composite material.

[0036] The application has the following beneficial effects:

[0037] 1. In the preparation process, the size of the zinc-triazole precursor Zn-met crystal particles is more uniform by reducing the dropping speed and performing aging treatment, and the size-uniformed precursor is beneficial to improving the structural uniformity of the porous carbon, increasing the specific surface area, and improving the mechanical properties and structural stability of the porous carbon during subsequent carbonization and calcination.

[0038] 2. During high-temperature carbonization of Zn-met, zinc can act as a pore-forming agent, reducing the introduction of pore-forming agents and the removal of subsequent impurity ions, and saving process costs.

[0039] 3. In-situ polymerization of polyaniline on the MOF-derived porous carbon replaces part of the active sites of the double-layer capacitor with active sites of the pseudo-capacitor, greatly improving the specific capacitance of the material.

[0040] 4. The MOF-derived porous carbon composite material improves the structural stability of the material, reduces the collapse of pores during long cycling, and is beneficial to improving the capacity retention rate during long cycling.

[0041] 5. The MOF-derived porous carbon composite electrode material is used as a negative electrode material to prepare a supercapacitor, which has a specific capacitance of 493 F·g -1 at a current density of 1 A·g -1 . The MOF-derived porous carbon composite electrode material is used as a negative electrode material, and CoNi2S4 / C-CNTs is used as a positive electrode material to prepare an asymmetric supercapacitor, which has a specific capacitance of 369 F·g -1 at 1 A·g -1 , an energy density of 131.2 Wh·kg -1 at a power density of 800 W·kg -1 , an energy density of 49.7 Wh·kg -1 at a power density of 16000 W·kg -1 , an energy density that is 2-3 times that of the prior art, and a high capacity retention rate of 92.5% after 40000 cycles, showing very excellent electrochemical performance and cycle stability. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 Synthetic route of Mpc@PANI-0.1.

[0043] Figure 2 SEM images of products in the process of preparing MOF derived porous carbon composite electrode materials, wherein (a) is the SEM image of the precursor Zn-met; (b) and (c) are the SEM images of Mpc@PANI-0.1; (d) is the SEM image of polyaniline particles on the surface of Mpc@PANI-0.1.

[0044] Figure 3 TEM image of Mpc@PANI-0.1.

[0045] Figure 4 XRD images of composites prepared at different aniline concentrations.

[0046] Figure 5 N2adsorption-desorption curve and corresponding pore size distribution of Mpc@PANI-0.1.

[0047] Figure 6 CV images of composites prepared at different aniline concentrations at 10 mV·S -1 .

[0048] Figure 7 GCD images of composites prepared at different aniline concentrations at 1 A·g -1 .

[0049] Figure 8 CV images of Mpc@PANI-0.1 at different scan rates.

[0050] Figure 9 GCD images of Mpc@PANI-0.1 at different current densities.

[0051] Figure 10 Long cycle stability test result images of CoNi2S4 / C-CNTs / / Mpc@PANI-0.1 asymmetric supercapacitor at a current density of 5 A·g -1 .

[0052] Figure 11 Structure schematic diagram of CoNi2S4 / C-CNTs / / Mpc@PANI-0.1 asymmetric supercapacitor. DETAILED DESCRIPTION

[0053] The technical solutions of the present application will be further described below in conjunction with the drawings, but the protection scope of the present application is not limited thereto.

[0054] Example 1

[0055] (1) Preparation of Zn-met

[0056] Dissolve 30 mmol Zn(CH3COO)2 in 80 mL of a mixed solution, in which the volume ratio of deionized water, ethanol, DMF (N,N-dimethylformamide), NH3·H2O (ammonia water concentration 25-28 wt.%) is 3:2:2:1, and stir at room temperature for 30 min to completely dissolve, then take 5 mL of 1H-1,2,3-triazole, and slowly drop it into the mixed solution, the drop speed is controlled at 3-5 s per drop, after all the drops are completed, stir at room temperature for 6 h, and then age for 24 h. The obtained product is washed with DMF, deionized water and ethanol in turn, and then dried in a vacuum oven at 60 ℃ for 24 h to obtain Zn-met (2.2 g).

[0057] (2) Preparation of porous carbon Mpc

[0058] Put 2 g of Zn-met in a quartz boat, heat to 800 ℃ at a heating rate of 5 ℃ / min in a tube furnace under N2 atmosphere, and anneal for 2 h. After cooling to room temperature, wash the product with 1 M hydrochloric acid to remove metal ions, then wash with deionized water, and then dry in an oven at 60 ℃ for 24 h to obtain MOF-derived porous carbon Mpc (0.5 g).

[0059] (3) Preparation of Mpc@PANI-0.1

[0060] Take 50 mL of 1 M hydrochloric acid to prepare an aniline hydrochloride mixed solution with aniline concentration of 0.1 M, then add 1 g of Mpc powder and stir at room temperature for 0.5 h to mix uniformly. Then pour 50 mL of 0.5 M ammonium persulfate solution into the above Mpc-containing solution and stir for 8 h, then centrifuge and wash several times with deionized water, and then dry in a vacuum oven at 60 ℃ for 12 h to obtain Mpc@PANI-0.1, which is a MOF-derived porous carbon composite electrode material. The synthesis route of Mpc@PANI-0.1 is shown in Figure 1

[0061] Comparative Example: Change the aniline concentration in the aniline hydrochloride mixed solution, and prepare aniline hydrochloride mixed solutions with aniline concentrations of 0.05 M, 0.2 M and 0.4 M, respectively, and the remaining steps remain unchanged, to prepare Mpc@PANI-0.05, Mpc@PANI-0.2 and Mpc@PANI-0.4, respectively. The composite materials with different aniline concentrations are named as Mpc@PANI-X.

[0062] (4) Preparation of electrode ​

[0063] The prepared MOF-derived porous carbon composite electrode material sample (active material), acetylene black (conductive agent) and polyvinylidene fluoride (binder) were weighed according to a mass ratio of 8:1:1, then the three substances were placed in a mortar for thorough grinding to make them uniformly mixed, and then transferred into a weighing bottle, an appropriate amount of N-methylpyrrolidone solvent was added and continuously stirred for 6 h to make the slurry uniformly dispersed. Then the slurry was uniformly coated on 1×1.5 cm 2 foam nickel (the coating area was controlled at 1×1 cm 2 as much as possible), vacuum dried at 60 °C for 12 h. After the electrode sheet was completely dried, it was placed between two pieces of 2×2 cm 2 foam nickel and pressed into a sheet under a pressure of 10 MPa, and then the excess part was cut off to obtain a working electrode of 1×1.5 cm 2 , (the uncoated side was close to the electrode clamp). The active material loading on each working electrode was about 1.0 ± 0.2 mg·cm -2 .

[0064] CoNi2S4 / C-CNTs / / Mpc@PANI-0.1 HSC asymmetric supercapacitor assembly: The asymmetric supercapacitor uses CoNi2S4 / C-CNTs as the positive electrode material, uses the prepared porous carbon Mpc@PANI-0.1 as the negative electrode, uses glass fiber filter paper as the separator, and uses 2 M KOH as the electrolyte.

[0065] CoNi2S4 / C-CNTs was prepared according to the method described in the literature Xinbiao Mao, Hongtao Guan, Jufeng Zhou, Wenwen Zhou, Xiaobei Shi, Xin Xu, Yunfang Gao, In-situ growth of series-connected CoNi2S4 hollow nanocages strung by carbon nanotubes for high-performance hybrid supercapacitors, Journal of Energy Storage, Volume 105, 2025, 114751:

[0066] 1. Preparation of ZIF-67 / C-CNTs: Firstly, 20 mg C-CNTs and 100 mg PVP were added into 30 mL MeOH, and then ultrasonic treatment was performed for 60 min to obtain a C-CNTs dispersion liquid A. Then, 1.164 g Co(NO3)2·6H2O and 1.314 g 2-methylimidazole were added into 25 mL MeOH respectively, and ultrasonic treatment was performed for 15 min to obtain a light red solution B and a colorless solution C. Finally, solution B was poured into dispersion liquid A, and stirring was performed for 30 min, and then solution C was quickly poured into the above system, and magnetic stirring was continuously performed at room temperature for 24 h. The product was centrifuged and washed several times with EtOH, and then dried in a vacuum oven at 60 ℃ for 12 h to obtain ZIF-67 / C-CNTs.

[0067] 2. Preparation of Co3S4 / C-CNTs: 100 mg ZIF-67 / C-CNTs and 300 mg TAA were weighed and added into 30 mL EtOH respectively, and stirring was performed until uniform, and then the dispersion liquid and the TAA solution were mixed and ultrasonic treatment was performed for 15 min, and then poured into a 100 mL polytetrafluoroethylene liner, and then sealed with an autoclave and placed in a 120 ℃ oven for 1 h. After the reaction was completed and cooled to room temperature, the product was taken out and washed several times with EtOH, and then placed in a 60 ℃ vacuum oven for 12 h to obtain Co3S4 / C-CNTs.

[0068] 3. Preparation of CoNi2S4 / C-CNTs: 100 mg Co3S4 / C-CNTs and 100 mg Ni(NO3)2·6H2O were weighed and added into 30 mL EtOH respectively, and stirring was performed until uniform, and then the dispersion liquid and the Ni(NO3)2·6H2O solution were mixed and ultrasonic treatment was performed for 15 min, and then poured into a 100 mL polytetrafluoroethylene liner, and then sealed with an autoclave and placed in a 160 ℃ oven for 4 h. After the reaction was completed and cooled to room temperature, the product was taken out and washed several times with EtOH, and then placed in a 60 ℃ vacuum oven for 12 h to obtain CoNi2S4 / C-CNTs.

[0069] The structure schematic diagram of the assembled CoNi2S4 / C-CNTs / / Mpc@PANI-0.1 asymmetric supercapacitor is shown in FIG. 1. Figure 11

[0070] Example 2

[0071] Test instruments and methods:

[0072] ​Phase characterization: Scanning electron microscopy (SEM, Gemini 500, Zeiss, Germany) and transmission electron microscopy (TEM, Tecnai G2 F30, FEI, Netherlands) were used to detect the morphology of the samples. X-ray diffraction spectrometer (XRD, D8 Advance, Bruker AXS, Germany) was used to analyze the phase and structure of the samples. Specific surface area, pore size distribution and pore volume of the samples were analyzed by specific surface area pore size distribution instrument (ASAP2460, Micromeritics, USA).

[0073] Electrochemical characterization: cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) tests were carried out in a three-electrode cell with 2 M KOH electrolyte. The CV test (test conditions: 0-1.7 V) was used to determine the working voltage range of the CoNi2S4 / C-CNTs / / Mpc@PANI-0.1 asymmetric supercapacitor. The GCD test was carried out at room temperature and atmospheric pressure on an electrochemical workstation (CHI 760E, Shanghai Chenhua Instrument Co., Ltd.).

[0074] The cycle performance of the CoNi2S4 / C-CNTs / / Mpc@PANI-0.1 asymmetric supercapacitor at a current density of 5 A·g-1 and a voltage range of 0-1.6 V at room temperature was detected on a blue light test system CT2001A instrument. During the electrochemical test, the capacitor was not subjected to additional pressure. -1 , room temperature. During the electrochemical test, the capacitor was not subjected to additional pressure.

[0075] The test results are as follows:

[0076] 1. Phase characterization

[0077] The SEM images of the products in the preparation of polyaniline-coated porous carbon material are as shown in Figure 2 , wherein (a) is the SEM image of the precursor Zn-met; (b) and (c) are the SEM images of different positions of Mpc@PANI-0.1; (d) is the SEM image of the polyaniline particles on the surface of Mpc@PANI-0.1.

[0078] The results show that (a) indicates that Zn-met has a rhombic octahedral morphology with a smooth surface. The size of most crystals is about 2-3 pm. (b) and (c) are the SEM images of Mpc@PANI-0.1. The porous sheet structure can be observed and has a certain upper and lower layering. The whole presents a huge honeycomb structure. The surface is covered with holes of different sizes, and is also covered with polyaniline nanoparticles, making the whole surface rough. (d) shows the polyaniline nanoparticles attached to the surface of Mpc@PANI-0.1.

[0079] TEM images of Mpc@PANI-0.1 are shown in FIG. 4, in which (a), (b), (c), (d) are different scales, respectively. The TEM images clearly show that a layer of polyaniline is coated on the surface of the porous carbon as a "coat", and it can be clearly seen that some of the cavities are also filled with polyaniline particles, and it can be seen that some of the polyaniline particles scattered around the porous carbon have a size of about 50 nm. At the same time, a large number of polyaniline nanoparticles can be clearly seen attached to the "coat". Figure 3 XRD patterns of Mpc and composite materials prepared by different concentrations of aniline Mpc@PANI-0.05, Mpc@PANI-0.1, Mpc@PANI-0.2 and Mpc@PANI-0.4 are shown in FIG. 5.

[0080] Figure 4 The XRD spectra of Mpc@PANI-X after high-temperature pyrolysis all only have a broad peak at 24.3 °, which corresponds to the (002) crystal plane of graphite, and there is no characteristic peak, indicating that the MOF has been completely converted into porous carbon after high-temperature pyrolysis. By comparing the XRD spectra of different aniline addition amounts, it can be found that all the spectra are almost identical, and the peak intensity also has no obvious difference, indicating that the coating of polyaniline does not change the original crystal structure of the carbon material.

[0081] N2 adsorption-desorption curve and corresponding pore size distribution of Mpc@PANI-0.1 are shown in FIG. 6. Figure 5 The results in the table show that the N2 adsorption-desorption curve of Mpc@PANI-0.1 shows type II adsorption-desorption curve, and the adsorption-desorption curve shows a clear hysteresis loop when the relative pressure (P / P0) is in the range of 0.4~0.9, indicating that the material has a mesoporous structure. From the pore size distribution graph, it can be seen that the mesopores of Mpc@PANI-0.1 are mainly concentrated in the range of 3.3~4.2 nm. Subsequently, the specific surface area is calculated to be 69.1 m 2 ·g -1 The presence of mesopores provides a large number of paths for rapid mass transfer, and makes it easier for electrolyte to enter the interior of the material, thereby utilizing more active sites and improving the electrochemical performance.

[0082] CV curves of composite materials prepared by different concentrations of aniline at a scan rate of 10 mV·S -1 Figure 6 ​​As shown in the CV curves, Mpc exhibits a standard rectangular shape, a characteristic of typical double-layer capacitor materials. In contrast, Mpc@PANI-X shows an additional pair of redox peaks at -0.23 V and -0.36 V on top of the original rectangular outline, corresponding to the oxidation and reduction peaks of polyaniline (PANI). Notably, the oxidation peaks of Mpc and Mpc@PANI-0.05 in the Mpc@PANI-X series samples are not obvious. However, with the increase of aniline addition during synthesis, Mpc@PANI-0.2 and Mpc@PANI-0.4 samples show obvious redox peaks, indicating that as the proportion of polyaniline gradually increases, more obvious polyaniline characteristics are exhibited. The rectangular outline and the appearance of redox peaks indicate that Mpc@PANI-X possesses both double-layer capacitance and pseudocapacitance characteristics during the electrochemical reaction. In all samples, the integrated area of ​​Mpc@PANI-X was larger than that of the original Mpc, indicating that the pseudocapacitance introduced by polyaniline can effectively increase the overall specific capacitance of the composite material. Among them, Mpc@PANI-0.1 showed the largest specific capacitance at 10 mV·s. -1 The largest integral area at the scan rate indicates that it has the largest specific capacitance. However, further increasing the aniline concentration actually decreases the specific capacitance of Mpc@PANI-0.2 and Mpc@PANI-0.4. This shows that adding an appropriate amount of PANI can effectively increase the specific capacitance, while excessive PANI does not effectively improve the overall specific capacitance of the material.

[0083] Composite materials prepared with different aniline concentrations at 1 A·g -1 GCD graph at scan rate as shown Figure 7 As shown, the GCD curve of Mpc exhibits a standard isosceles triangle, a typical characteristic of double-layer capacitor materials. However, the Mpc@PANI-X material deviates to varying degrees from the original isosceles triangle outline, and shows significant slope changes at -0.38 V and -0.33 V. This corresponds to a pair of redox peaks in the CV curve, indicating that the composite material simultaneously possesses both double-layer capacitance and pseudocapacitance charge storage mechanisms. Furthermore, the GCD curve shows that Mpc@PANI-0.1 has the longest discharge time among all materials, which corresponds to the largest peak area in the CV curve.

[0084] The CV plots of Mpc@PANI-0.1 at different voltage scan rates are as follows: Figure 8As shown in the figure, the shape of the CV curve did not change significantly with the increase of the scan rate, and the redox peaks only shifted slightly, proving that Mpc@PANI-0.1 has good kinetic reversibility and fast charge transfer capability. Meanwhile, the potential difference between the oxidation and reduction peaks gradually widens, which is due to the internal resistance hindering ion diffusion during the rapid redox process, causing the electrode kinetics to gradually be controlled by the diffusion step.

[0085] The GCD plots of Mpc@PANI-0.1 at different current densities are as follows: Figure 9 As shown in the figure, the results indicate that as the current density increases, the inflection point of the charge-discharge curve gradually disappears, and the shape of the GCD curve gradually approaches the isosceles triangle shape of an ideal double-layer capacitor, indicating that the response at high current densities is mainly due to the double-layer capacitance of the carbon material. The approximately symmetrical curve demonstrates that the material has good coulombic efficiency and electrochemical reversibility.

[0086] CoNi2S4 / C-CNTs / / Mpc@PANI-0.1 asymmetric supercapacitor at 5 A·g -1 The long-cycle stability test results at current density are shown in the figure. Figure 10 As shown in the figure, the long-cycle stability test results show that the supercapacitor maintains an ultra-high capacitance retention rate during cycling. Even after 40,000 constant current charge-discharge cycles, it can still retain 92.5% of its initial capacitance, and its coulombic efficiency remains relatively stable during cycling, demonstrating its excellent cycle stability.

[0087] According to the literature, CoNi2S4 / C-CNTs / / AC (commercial rice husk carbon) assembled using the same positive electrode CoNi2S4 / C-CNTs retained 90% of its capacity after 8500 cycles.

[0088] It is evident that when Mpc@PANI-0.1 of the present invention is used as an electrode material, its electrochemical performance and cycle stability are significantly improved compared to existing anode materials.

Claims

1. A method for preparing a MOF-derived porous carbon composite electrode material, characterized in that The method comprises the following steps: (1) zinc salt is dissolved in a mixed solvent of ethanol, DMF, ammonia water and water, triazole is added dropwise, and the reaction is stirred at room temperature for 5-10 h, and then aged for 20-30 h to obtain a solid product, which is washed and dried to obtain a zinc-triazole MOF; (2) the zinc-triazole MOF is calcined at 800-850°C for 2-4 h under the protection of inert gas, and then washed to remove metal ions and dried to obtain a MOF-derived porous carbon; (3) the MOF-derived porous carbon is added into an aniline hydrochloride solution, uniformly dispersed, and then an ammonium persulfate solution is added, and the reaction is stirred for 5-10 h, and then the product is washed with water and dried to obtain a MOF-derived porous carbon composite electrode material.

2. The method of claim 1, wherein In step (1), the zinc salt is a water-soluble zinc salt, and the volume ratio of water, ethanol, DMF (N,N-dimethylformamide) and ammonia water in the mixed solvent is 3-3.5:2-2.2:2-2.2:0.8-1.2; the mass concentration of ammonia water is 25-28%.

3. The method of claim 1, wherein In step (1), the dropping speed of ammonia water is 0.004-0.01 mL / s.

4. The method of claim 1, wherein In step (1), the molar ratio of zinc salt to triazole is 1:2.5-3.

5.

5. The method of claim 1, wherein In step (2), the metal ions are removed by washing with dilute hydrochloric acid, and then washed with deionized water.

6. The method of claim 1, wherein In step (3), the concentration of aniline in the aniline hydrochloride solution is 0.05-0.4 mol / L, and the concentration of dilute hydrochloric acid is 0.5-2 mol / L.

7. The method of claim 1, wherein In step (3), the mass ratio of aniline to ammonium persulfate is 1:3-24.

8. The MOF-derived porous carbon composite electrode material prepared by the method of any one of claims 1-7.

9. The use of the MOF-derived porous carbon composite electrode material of claim 8 in the preparation of a supercapacitor.

10. An asymmetric supercapacitor, characterized by The asymmetric capacitor uses the MOF-derived porous carbon composite electrode material of claim 8 as a negative electrode material.

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