Preparation method of a novel self-supporting porous supercapacitor material

Abstract

This invention provides a novel method for preparing a self-supporting porous supercapacitor material, belonging to the field of supercapacitor electrode materials. The preparation method includes the following steps: immersing nickel foam in a corrosion solution containing iron salts and a sulfur source, then placing it within the coil of an alternating magnetic field induction heating device for in-situ corrosion reaction, generating an Fe-doped nickel-based composite on the pore walls of the nickel foam, thus obtaining a precursor; drying and oxidizing the precursor to obtain the novel self-supporting porous supercapacitor material; the sulfur source includes one or both of thiosulfate and thiourea; the nickel-based composite includes Ni(OH)₂ and Ni₃S₂; the nickel-based composite is a porous structure composed of nanoclusters; adjacent pores in the porous structure are interconnected. The synergistic effect of the thermal, electric, and magnetic fields of the alternating magnetic field accelerates corrosion kinetics, promotes the formation of a bicontinuous porous structure, and enhances the electrochemical energy storage performance of the material.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of supercapacitor electrode materials, in particular to a preparation method of a novel self-supporting porous supercapacitor material. BACKGROUND

[0002] As a new type of electrochemical energy storage device between traditional capacitors and secondary batteries, supercapacitors have the advantages of high power density, long cycle life, fast charge and discharge capability, and wide working temperature range, and have broad application prospects in new energy vehicles, portable electronic devices, power grid frequency modulation and energy storage systems.

[0003] The electrode material is the core component that determines the energy storage performance of the supercapacitor, and the self-supporting electrode does not need to add a binder and a conductive agent, which can effectively reduce the electrode interface impedance and simplify the preparation process. At the same time, the three-dimensional conductive substrate can provide sufficient loading sites and continuous electron transmission channels for active materials, which is the research hotspot of current supercapacitor electrode materials.

[0004] Foamed nickel, with its three-dimensional interconnected porous framework, excellent electrical conductivity, good mechanical flexibility and chemical stability, is one of the most commonly used substrate materials for self-supporting electrodes. At present, the preparation methods of self-supporting electrodes based on foamed nickel mainly include hydrothermal synthesis, electrochemical deposition, sol-gel method and chemical corrosion method. Among them, the hydrothermal synthesis method has a long reaction period, high energy consumption, and strict requirements for reaction equipment; the electrochemical deposition method has weak binding force between active materials and substrate, and is easy to fall off during the cycle process; the traditional chemical corrosion method has slow reaction rate, poor controllability of pore structure and morphology, and the prepared electrode material has low specific capacitance and large charge transfer impedance, which is difficult to meet the application requirements of high-performance supercapacitors. SUMMARY

[0005] The present application provides a preparation method of a novel self-supporting porous supercapacitor material, which can quickly prepare a self-supporting supercapacitor electrode material with a double-continuous pore structure, high specific capacitance, low impedance and high cycle stability.

[0006] The present application provides a preparation method of a novel self-supporting porous supercapacitor material, which comprises the following steps: After immersing the foamed nickel in a corrosion solution containing iron salt and sulfur source, the foamed nickel is placed in the coil of an alternating magnetic field induction heating device for in-situ corrosion reaction, and a Fe element doped nickel-based composite is generated on the pore wall of the foamed nickel to obtain a precursor; The precursor is dried and oxidized to obtain the novel self-supporting porous supercapacitor material; The sulfur source includes one or both of thiosulfate and thiourea; The nickel-based composite comprises Ni(OH)2 and Ni3S2; the nickel-based composite is a porous structure composed of nanoclusters; adjacent pores in the porous structure are interconnected.

[0007] Preferably, the length, width, and thickness of the nickel foam are 1 cm, 2.5 cm, and 1.6 mm, respectively, and the porosity is 80~120 ppi.

[0008] Preferably, the iron salt includes ferric nitrate.

[0009] Preferably, the concentration of iron salt in the corrosive solution is 30~43 mmol / L.

[0010] Preferably, the thiosulfate includes sodium thiosulfate.

[0011] Preferably, the concentration of the sulfur source in the corrosive solution is 10~20 mmol / L.

[0012] Preferably, the sinusoidal current during the in-situ corrosion reaction is 3.6~7A, the frequency is 100~300kHz, and the time is 660~1200s.

[0013] Preferably, the diameter of the coil is 6 cm and the number of turns is 3.

[0014] Preferably, the drying oxidation is carried out in an atmospheric environment; The drying and oxidation time is 8-12 hours.

[0015] The present invention also provides a novel self-supporting porous supercapacitor material prepared by the preparation method described above, comprising nickel foam and a nickel-based composite material doped with Fe on the pore walls of the nickel foam; The nickel-based composite is a porous structure composed of nanoclusters; adjacent pores in the porous structure are interconnected.

[0016] The iron element includes Fe. 3+ or Fe 2+ with Fe 3+ .

[0017] An alternating magnetic field accelerates the corrosion reaction kinetics through an induced heating effect (i.e., the Ni on the surface of the nickel foam is corroded by Fe in the corrosion solution). 3+ Oxidized to Ni 2+The corrosion process generates nickel-based composites by in-situ corrosion of ions. Simultaneously, the Lorentz force of the magnetic field regulates the transport and deposition of ions during corrosion. Furthermore, by adjusting the type of sulfur source, a bicontinuous porous structure composed of nanoclusters is formed on the surface of the nickel foam substrate (i.e., adjacent pores in the nickel-based composite are connected in both the horizontal and vertical directions). This provides ample channels and active sites for the rapid transport of electrolyte ions during use. During in-situ corrosion, a nickel-based composite is generated on the surface of the nickel foam, forming a strong bond with the substrate without the need for a binder. This significantly reduces interfacial charge transfer impedance and enhances the electrode's electronic conductivity and energy storage performance.

[0018] This invention employs a preparation process using alternating magnetic field induction heating coupled with corrosion engineering. This process results in a fast reaction rate and a short preparation cycle, requiring only a few minutes to complete material synthesis. Through the synergistic effect of the thermal, electric, and magnetic fields of the alternating magnetic field, the pore structure and morphology of the electrode material can be precisely controlled. A bicontinuous porous structure is constructed on the surface of nickel foam, effectively improving the diffusion rate of electrolyte ions and the utilization rate of active sites. Compared with the traditional hydrothermal method, this significantly improves production efficiency, reduces energy consumption, and enhances the electrochemical performance of the material. Attached Figure Description

[0019] Figure 1 The diagram shows the structure of the apparatus used in the embodiment and the structure of the self-supporting electrode material prepared therefrom. Figure 2 The cyclic voltammetry (CV) curves of the electrode materials obtained in Examples 1-6 and Comparative Examples 1-2 at a scan rate of 20 mV / s are shown. Figure 3 This is a comparison chart of the electrochemical performance of the electrode materials obtained in Example 1; Figure 4 The image shows the characterization spectrum of the electrode material obtained in Example 1. Detailed Implementation

[0020] This invention provides a novel method for preparing a self-supporting porous supercapacitor material, comprising the following steps: After being immersed in a corrosion solution containing iron salts and sulfur sources, nickel foam is placed in the coil of an alternating magnetic field induction heating device to carry out in-situ corrosion reaction, generating Fe-doped nickel-based composites on the pore walls of the nickel foam, thus obtaining the precursor. The precursor is dried and oxidized to obtain the novel self-supporting porous supercapacitor material. The sulfur source includes one or both of thiosulfate and thiourea; The nickel-based composite comprises Ni(OH)2 and Ni3S2; the nickel-based composite is a porous structure composed of nanoclusters; adjacent pores in the porous structure are interconnected.

[0021] Prior to the impregnation, the present invention preferably further includes cleaning and drying the nickel foam.

[0022] In this invention, the cleaning process preferably includes ultrasonic cleaning sequentially in ethanol, hydrochloric acid, and deionized water. The ultrasonic cleaning time in ethanol, hydrochloric acid, and deionized water is preferably 5 minutes; the concentration of the hydrochloric acid is preferably 3 mol / L. This invention removes oil, oxide layers, and impurities from the surface of the nickel foam through cleaning.

[0023] In this invention, the length, width, and thickness of the nickel foam are preferably 1 cm, 2.5 cm, and 1.6 mm, respectively, and the porosity is preferably 80~120 ppi. In specific embodiments of this invention, it can be 90 ppi, 100 ppi, or 110 ppi.

[0024] In this invention, the impregnation is preferably performed by vertically immersing nickel foam in a corrosive solution containing iron salts and a sulfur source.

[0025] In this invention, the concentration of iron salt in the corrosive solution is preferably 30-43 mmol / L, and in specific embodiments of this invention, it can be 31 mmol / L, 32 mmol / L, 33 mmol / L, 34 mmol / L, 35 mmol / L, 36 mmol / L, 37 mmol / L, 38 mmol / L, 39 mmol / L, 40 mmol / L, 41 mmol / L, or 42 mmol / L; the iron salt preferably includes ferric nitrate. The Fe in the iron salt... 3+ The primary corrosive agent oxidizes the Ni on the surface of the nickel foam to Ni. 2+ ion.

[0026] In this invention, the concentration of the sulfur source in the etching solution is preferably 10-20 mmol / L, and in specific embodiments, it can be 11 mmol / L, 12 mmol / L, 13 mmol / L, 14 mmol / L, 15 mmol / L, 16 mmol / L, 17 mmol / L, 18 mmol / L, or 19 mmol / L. The sulfur source includes one or both of thiosulfate and thiourea; the thiosulfate preferably includes sodium thiosulfate. This invention prepares an electrode with good performance by adjusting the sulfur source. Based on the comparison of capacitance performance, thiosulfate is preferred as the sulfur source for the etching solution.

[0027] In this invention, the diameter of the coil is preferably 6 cm, and the number of turns is preferably 3.

[0028] In this invention, the sinusoidal current during the in-situ corrosion reaction is preferably 3.6~7A, the frequency is preferably 100~300kHz, and the time is preferably 660~1200s. In specific embodiments of this invention, the sinusoidal current can be 4A, 4.5A, 5A, 5.5A, 6A, or 6.5A, the frequency can be 120kHz, 150kHz, 180kHz, 200kHz, 220kHz, 250kHz, or 280kHz, and the time can be 700s, 750s, 850s, 900s, 950s, 1000s, 1050s, 1100s, or 1150s.

[0029] This invention obtains a suitable magnetic field by adjusting the diameter and number of turns of the coil and coordinating with sinusoidal current, frequency and time, so that the ion transport and deposition behavior during the corrosion process are matched, promoting the formation of a bicontinuous pore structure composed of nanoclusters on the surface of the nickel foam substrate.

[0030] The alternating magnetic field accelerates the corrosion reaction kinetics through induced thermal effect (i.e., nickel foam participates in the reaction to generate nickel-based composites). At the same time, the Lorentz force of the magnetic field can regulate the transport and deposition behavior of ions during corrosion, promoting the formation of a double continuous pore structure composed of nanoclusters on the surface of the nickel foam substrate (i.e., adjacent pores in the nickel-based composite are interconnected in both the horizontal and vertical directions). This provides sufficient channels and active sites for the rapid transport of electrolyte ions during use. During in-situ corrosion, nickel-based composites are generated on the surface of the nickel foam in situ, forming a strong bond with the substrate without the need for binders. This significantly reduces the interfacial charge transfer impedance and improves the electron conductivity and energy storage performance of the electrode.

[0031] Following the in-situ corrosion reaction, the present invention preferably further includes washing the obtained product to obtain the precursor.

[0032] In this invention, the washing process preferably includes rinsing with deionized water and ethanol in sequence. This invention removes residual corrosive liquid from the surface through washing.

[0033] After obtaining the precursor, the present invention dries and oxidizes the precursor to obtain the novel self-supporting porous supercapacitor material.

[0034] In this invention, the drying and oxidation time is preferably 8 to 12 hours, and in specific embodiments of this invention, it can be 9 hours, 10 hours, or 11 hours.

[0035] In this invention, the drying oxidation is preferably carried out in an atmospheric environment. Dry oxidation can remove Fe from the Fe-doped nickel-based composite. 2+ Oxidized to Fe 3+ This further leads to the formation of heterogeneous structures, which enhances the intrinsic site activity on the material surface.

[0036] The present invention also provides a novel self-supporting porous supercapacitor material prepared by the preparation method described above, comprising nickel foam and a nickel-based composite material doped with Fe on the pore walls of the nickel foam; The nickel-based composite is a porous structure composed of nanoclusters; adjacent pores in the porous structure are interconnected, which promotes ion diffusion and electron conduction in the electrochemical reaction.

[0037] In this invention, the iron element preferably includes Fe. 3+ or Fe 2+ with Fe 3+ .

[0038] The following detailed description of the preparation method of the novel self-supporting porous supercapacitor material provided by the present invention, in conjunction with the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0039] Figure 1 The diagram shows the structure of the device used in the embodiment and the structure of the self-supporting electrode material prepared.

[0040] Example 1 (1) Substrate pretreatment: Cut the nickel foam into sheets of 1cm×2.5cm with a porosity of 110ppi, and clean them with ethanol, hydrochloric acid and deionized water under ultrasonic treatment for 5 minutes to remove surface oil, oxide layer and impurities for later use. (2) Preparation of corrosion solution: Dissolve ferric nitrate in deionized water, add sodium thiosulfate and stir magnetically for 5 min to prepare 50 mL of corrosion solution, so that the concentrations of ferric nitrate and sodium thiosulfate in the solution are 43 mmol / L and 20 mmol / L, respectively. (3) Induction heating corrosion reaction: The pretreated nickel foam was vertically and completely immersed in the above-mentioned beaker with a diameter of 5.5 cm containing 50 mL of corrosion solution. The beaker was placed in a three-turn induction heating coil with a diameter of 6 cm. The sinusoidal current of the coil was set to 7 A and the frequency was 150 kHz. The reaction was carried out under induction heating for 780 s to obtain the electrode precursor. (4) Post-processing: After the reaction is completed, the sample is taken out and rinsed three times with deionized water and ethanol respectively. It is then placed in the atmosphere to dry and oxidize naturally for 12 hours to obtain self-supporting porous supercapacitor material.

[0041] The morphology and elemental composition of the material prepared in this embodiment were characterized by SEM and EDS. The results showed that a bicontinuous porous structure composed of nanoclusters was formed on the material surface, with Ni atomic percentages of 76.35 at, O at 15.12 at, S at 8.41 at, and Fe at 0.12 at. XPS characterization results confirmed that Ni(OH)2 / Ni3S2 composite active material was generated in situ on the material surface.

[0042] The electrochemical performance of the material prepared in this embodiment was tested using a three-electrode system (the material prepared in this embodiment was the working electrode, the platinum sheet was the counter electrode, and the calomel electrode was the reference electrode, tested in 1 mol / L KOH solution). The results showed that the electrode areal capacitance reached 3.64 F·cm at a scan rate of 20 mV / s. -2 The increase in efficiency compared to induction-free heating is 6.1 times; 10 mA·cm -2 Under high current charge and discharge, the coulombic efficiency reaches 90%; electrochemical impedance spectroscopy tests show that the charge transfer resistance of the electrode is 71.22Ω, demonstrating excellent electronic conductivity and electrochemical energy storage performance.

[0043] Example 2 (1) Substrate pretreatment: Same as in Example 1; (2) Preparation of the corrosive solution: Same as in Example 1; (3) Induction heating corrosion reaction: The pretreated foamed nickel was vertically immersed in the corrosion solution and placed in an induction heating coil of the same specification. The sinusoidal current of the coil was set to 7A and the frequency was 150kHz. The reaction was carried out under induction heating for 900s to obtain the electrode precursor. (4) Post-processing: Same as in Example 1, to obtain self-supporting porous supercapacitor material.

[0044] The same methods as in Example 1 were used for characterization and testing. The results showed that the prepared material had the same Ni(OH)2 / Ni3S2 composite active material and microstructure as the material in Example 1, and the electrode area capacitance was 2.91 F·cm at a scan rate of 20 mV / s. -2 .

[0045] Example 3 (1) Substrate pretreatment: Same as in Example 1; (2) Preparation of the corrosive solution: Same as in Example 1; (3) Induction heating corrosion reaction: The pretreated foamed nickel was vertically immersed in the corrosion solution and placed in an induction heating coil of the same specification. The sinusoidal current of the coil was set to 5A and the frequency was 150kHz. The reaction was carried out under induction heating for 780s to obtain the electrode precursor. (4) Post-processing: Same as in Example 1, to obtain self-supporting porous supercapacitor material.

[0046] The same methods as in Example 1 were used for characterization and testing. The results showed that the prepared material had the same Ni(OH)2 / Ni3S2 composite active material and microstructure as the material in Example 1, and the electrode area capacitance was 2.57 F·cm at a scan rate of 20 mV / s. -2 .

[0047] Example 4 (1) Substrate pretreatment: Same as in Example 1; (2) Preparation of the corrosive solution: Same as in Example 1; (3) Induction heating corrosion reaction: Same as in Example 1 (4) Post-processing: After the process is completed, the sample is taken out and rinsed three times with deionized water and ethanol respectively. It is then placed in the atmosphere to dry and oxidize naturally for 8 hours to obtain self-supporting porous supercapacitor material.

[0048] The same methods as in Example 1 were used for characterization and testing. The results showed that the prepared material had the same Ni(OH)2 / Ni3S2 composite active material and microstructure as the material in Example 1, and the electrode area capacitance was 3.12 F·cm at a scan rate of 20 mV / s. -2 .

[0049] Example 5 (1) Substrate pretreatment: Same as in Example 1; (2) Preparation of the corrosive solution: Same as in Example 1; (3) Induction heating corrosion reaction: The pretreated foamed nickel was immersed in the corrosion solution and placed in an induction heating coil of the same specification. The sinusoidal current of the coil was set to 5A and the frequency was 150kHz. The reaction was carried out under induction heating for 900s to obtain the electrode precursor. (4) Post-processing: Same as in Example 1, to obtain self-supporting porous supercapacitor material.

[0050] The same methods as in Example 1 were used for characterization and testing. The results showed that the prepared material had the same Ni(OH)2 / Ni3S2 composite active material and microstructure as the material in Example 1, and the electrode area capacitance was 3.05 F·cm at a scan rate of 20 mV / s. -2 .

[0051] Example 6 (1) Substrate pretreatment: Same as in Example 1; (2) Preparation of corrosion solution: Dissolve ferric nitrate in deionized water, add thiourea and stir magnetically for 5 min to prepare 50 mL of corrosion solution, so that the concentrations of ferric nitrate and thiourea in the solution are 43 mmol / L and 20 mmol / L, respectively. (3) Induction heating corrosion reaction: Same as in Example 1; (4) Post-processing: Same as in Example 1, to obtain the comparative electrode material with induction heating.

[0052] The same methods as in Example 1 were used for characterization and testing. The results showed that the prepared material surface had no obvious porous nanocluster structure, and the electrode areal capacitance was 3.04 F·cm at a scan rate of 20 mV / s. -2 .

[0053] Comparative Example 1 (1) Substrate pretreatment: Same as in Example 1; (2) Preparation of the corrosive solution: Same as in Example 1; (3) Induction-free heating corrosion reaction: The pretreated nickel foam was completely immersed in the above 50 mL corrosion solution and allowed to stand at room temperature for 780 s to obtain the electrode precursor. (4) Post-processing: Same as in Example 1, to obtain a comparative electrode material without induction heating.

[0054] The material was characterized and tested using the same method as in Example 1. The results showed that there was no obvious porous nanocluster structure on the material surface, and the electrode area capacitance was only 0.62 F·cm at a scan rate of 20 mV / s. -2 The electrochemical performance is far lower than that of the materials prepared in the embodiments of this invention.

[0055] Comparative Example 2 (1) Substrate pretreatment: Same as in Example 1; (2) Preparation of corrosion solution: Dissolve ferric nitrate in deionized water, add sodium sulfate and stir magnetically for 5 min to prepare 50 mL of corrosion solution, so that the concentrations of ferric nitrate and sodium sulfate in the solution are 43 mmol / L and 20 mmol / L, respectively. (3) Induction heating corrosion reaction: Same as in Example 1; (4) Post-processing: Same as in Example 1, to obtain the comparative electrode material with induction heating.

[0056] The material was characterized and tested using the same method as in Example 1. The results showed that the prepared material surface had no obvious porous nanocluster structure, and the electrode areal capacitance was 0.96 F·cm at a scan rate of 20 mV / s. -2 .

[0057] Figure 2 The cyclic voltammetry (CV) curves of the electrode materials obtained in Examples 1-6 and Comparative Examples 1-2 at a scan rate of 20 mV / s are shown. Figure 3 This is a comparison chart of the electrochemical performance of the electrode materials obtained in Example 1. Figure 3 In the middle, (a) is the cyclic voltammetry (CV) curve at different scan rates, (b) is the electrochemical impedance spectroscopy (EIS) diagram, and (c) is the galvanostatic charge-discharge curve (GCD) at different current densities.

[0058] Depend on Figure 3 It can be seen that, due to the in-situ generation of Ni(OH)2 / Ni3S2 composite active material in the prepared self-supporting electrode material, the charge transfer resistance is as low as 71.22Ω, and the areal capacitance can reach as high as 3.70 F·cm at a scan rate of 20 mV / s. -2 Compared to samples without induction heating, the improvement is more than 6 times, 10 mA·cm -2 Under high current charge and discharge, the coulombic efficiency can reach 93%, demonstrating excellent electrochemical energy storage performance.

[0059] Figure 4 The image shows the characterization spectrum of the electrode material obtained in Example 1. Figure 4 (a) shows the SEM image and EDS elemental distribution map, (b) shows the XPS full spectrum, and (c) shows the Raman full spectrum.

[0060] SEM characterization results showed that, compared with the control group without induction heating, the induced thermal effect of the alternating magnetic field significantly accelerated the corrosion kinetics process, causing the nickel foam substrate to undergo layer-by-layer corrosion and form a bicontinuous porous structure assembled from nanoclusters.

[0061] EDS energy dispersive spectroscopy quantitative analysis and elemental surface distribution results show that the prepared electrode material mainly contains four characteristic elements: Ni, O, S, and Fe. Ni accounts for 76.35 at%, O for 15.12 at%, S for 8.41 at%, and Fe for 0.12 at%, directly confirming the successful doping of Fe and the effective introduction of S. The elemental surface distribution results show that Ni, O, S, and Fe exhibit a uniform distribution on the material surface without obvious elemental agglomeration, indicating that the induction heating preparation process achieves uniform loading of active components on the nickel foam substrate, avoiding the problem of localized component unevenness. Furthermore, compared with the control group without induction heating, the sample prepared by induction heating has significantly higher S and O content, further verifying the promoting effect of the alternating magnetic field on the formation of sulfide and hydroxide active substances.

[0062] XPS high-resolution spectroscopy and fitting data show that Ni and Ni in the Ni 2p spectrum 2+ with Ni 3+ The presence of characteristic peaks confirms the coexistence of the Ni(OH)2 active phase and the nickel foam metal substrate; Fe 2p spectrum shows Fe 2+ with Fe 3+The characteristic peaks confirmed the successful introduction of Fe element into the active material lattice as a dopant. The S 2p spectrum yielded characteristic peaks of metal-sulfur bonds (MS), corresponding to the characteristic chemical state of the Ni3S2 phase. The concurrently appearing SO bond characteristic peak matched the oxygen-containing sulfur species on the material surface. The fitting results of the O 1s spectrum corresponded to metal hydroxyl bonds (M-OH), lattice oxygen, and adsorbed water, further confirming the presence of the Ni(OH)2 phase. The Raman spectroscopy results were in high agreement with the XPS analysis conclusions, with clear characteristic Raman shift peaks of Ni(OH)2 and Ni3S2 in the spectra, clearly identifying the main phase of the material as a Ni(OH)2 / Ni3S2 composite.

[0063] The above morphology, composition and phase results prove that the present invention has successfully prepared a target Fe-doped Ni(OH)2 / Ni3S2 self-supporting porous composite electrode material by using an alternating magnetic field induction heating-assisted controlled corrosion process. Its unique porous structure and multi-component composite phase provide core support for its excellent electrochemical energy storage performance.

[0064] Table 1. Area capacitance of the supercapacitor materials obtained in Examples 1-6 and Comparative Examples 1-2

[0065] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a novel self-supporting porous supercapacitor material, characterized in that, Includes the following steps: After being immersed in a corrosion solution containing iron salts and sulfur sources, nickel foam is placed in the coil of an alternating magnetic field induction heating device to carry out in-situ corrosion reaction, generating Fe-doped nickel-based composites on the pore walls of the nickel foam, thus obtaining the precursor. The precursor is dried and oxidized to obtain the novel self-supporting porous supercapacitor material. The sulfur source includes one or both of thiosulfate and thiourea; The nickel-based composite comprises Ni(OH)2 and Ni3S2; the nickel-based composite is a porous structure composed of nanoclusters; adjacent pores in the porous structure are interconnected.

2. The preparation method according to claim 1, characterized in that, The length, width, and thickness of the nickel foam are 1 cm, 2.5 cm, and 1.6 mm, respectively, and the porosity is 80~120 ppi.

3. The preparation method according to claim 1, characterized in that, The iron salts include ferric nitrate.

4. The preparation method according to claim 1 or 3, characterized in that, The concentration of iron salts in the corrosive solution is 30-43 mmol / L.

5. The preparation method according to claim 1, characterized in that, The thiosulfate includes sodium thiosulfate.

6. The preparation method according to claim 1 or 5, characterized in that, The concentration of the sulfur source in the corrosive solution is 10~20 mmol / L.

7. The preparation method according to claim 1, characterized in that, The sinusoidal current during the in-situ corrosion reaction is 3.6~7A, the frequency is 100~300kHz, and the time is 660~1200s.

8. The preparation method according to claim 1 or 7, characterized in that, The coil has a diameter of 6cm and 3 turns.

9. The preparation method according to claim 1, characterized in that, The drying oxidation is carried out in an atmospheric environment; The drying and oxidation time is 8-12 hours.

10. The novel self-supporting porous supercapacitor material prepared by the preparation method according to any one of claims 1 to 9, characterized in that, Includes nickel foam and a nickel-based composite doped with Fe on the pore walls of the nickel foam; The nickel-based composite is a porous structure composed of nanoclusters; adjacent pores in the porous structure are interconnected. The iron element includes Fe. 3+ or Fe 2+ with Fe 3+ .

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