Composite supercapacitor material, preparation method thereof and supercapacitor

Abstract

The invention provides a composite supercapacitor material, a preparation method thereof and a supercapacitor, and the preparation method comprises the following steps: immersing a foam metal substrate in a sulfur-molybdenum source deposition solution, and carrying out the first electrodeposition to obtain a foam metal substrate loaded with amorphous molybdenum sulfide; and immersing the foam metal substrate loaded with amorphous molybdenum sulfide into a silver source deposition solution, and carrying out second electrodeposition to obtain the composite supercapacitor material which comprises the foam metal substrate loaded with amorphous molybdenum sulfide and silver. According to the preparation method, the silver-amorphous molybdenum sulfide-foam metal composite electrode material is prepared through two-step electrochemical deposition, the preparation process is simplified, high temperature and high pressure are not needed, large-scale production can be achieved, and a high-performance water-based and solid-state symmetric supercapacitor constructed based on the material has a good application prospect. And collaborative improvement of energy density and power density and practicability of a solid-state device can be realized.

Description

Technical Field

[0001] This invention belongs to the field of supercapacitor technology, and relates to a composite supercapacitor material, its preparation method, and a supercapacitor. Background Technology

[0002] In recent years, high-performance electrochemical energy storage devices have become a critical necessity. Compared with traditional batteries, supercapacitors have advantages such as fast charging speed, long charging time, and low maintenance costs, making them widely applicable in fields such as mobile communications, aerospace, medical devices, defense, transportation, and electronic information.

[0003] The power density and energy density of supercapacitors mainly depend on the charge storage mechanism, which is influenced by the interaction between the electrodes and the electrolyte. Therefore, the selection of electrode materials is crucial for optimizing supercapacitor performance. Currently, the main electrode materials for supercapacitors involve carbon materials, conductive polymers, metal oxides, and metal sulfides. Among these materials, transition metal sulfides are widely considered to be highly promising supercapacitor electrode materials due to their high theoretical specific capacitance and low electronegativity, which provides a fast channel for ion transport. However, their intrinsic electronic conductivity is insufficient, and they are prone to volume expansion and active site aggregation during charging and discharging, resulting in actual specific capacitance and energy density that are far lower than theoretical values. This problem severely restricts their practical application.

[0004] Therefore, in the existing technology system of supercapacitor electrode materials, single metal sulfides generally face problems such as low specific capacitance and poor cycle stability, making it difficult to meet the requirements of high-performance energy storage. Furthermore, although some composite electrode materials can alleviate the above problems to a certain extent, they have limitations such as complicated preparation processes and high costs, and it has always been difficult to break through the balance bottleneck in the synergistic optimization of energy density, power density and cycle stability.

[0005] Based on the above research, the development of a supercapacitor material with outstanding specific capacitance, excellent conductivity, and simple preparation method is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a composite supercapacitor material, its preparation method, and a supercapacitor. The preparation method obtains a silver-amorphous molybdenum sulfide-foam metal composite electrode material through two-step electrochemical deposition, which simplifies the preparation process, eliminates the need for high temperature and high pressure, enables large-scale production, and allows for the construction of high-performance aqueous and solid-state symmetric supercapacitors based on this material, which can achieve synergistic improvement in energy density and power density and the practical application of solid-state devices.

[0007] To achieve this objective, the present invention employs the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a composite supercapacitor material, the method comprising the following steps:

[0009] (1) The foam metal substrate is immersed in the sulfur-molybdenum source deposition solution and the first electrodeposition is performed to obtain a foam metal substrate loaded with amorphous molybdenum sulfide;

[0010] (2) Immerse the foam metal substrate loaded with amorphous molybdenum sulfide described in step (1) into the silver source deposition solution and perform a second electrodeposition to obtain the composite supercapacitor material, wherein the composite supercapacitor material includes a foam metal substrate loaded with amorphous molybdenum sulfide and silver.

[0011] This invention addresses the problems of poor intrinsic electronic conductivity, resulting in low energy density, and the cumbersome, costly, and demanding preparation methods for composite supercapacitor materials, when using single sulfides as electrode materials. It proposes a two-step electrodeposition method to obtain a silver-amorphous molybdenum sulfide-foam metal material. In the first step, molybdenum sulfide is deposited, followed by silver deposition. This simple and controllable process eliminates the need for high temperature and high pressure, enabling large-scale production. The two-step electrodeposition process allows for precise control of the loading amounts of molybdenum sulfide and silver, achieving a maximum loading intensity of 2.8 mg·cm⁻¹. -2 The active material is uniformly coated within the three-dimensional channels of the foamed metal, avoiding the problems of local agglomeration and uneven loading in traditional processes. Simultaneously, the electrodeposition process requires no additional binder, significantly improving the bonding strength between the active material and the substrate. This effectively suppresses the shedding of the active material during cyclic charging and discharging, further ensuring the long-term stability of the electrode. The resulting composite supercapacitor material exhibits a rich array of electroactive sites and rapid transport channels, resulting in a significant synergistic effect. It demonstrates high specific capacitance and good cycling stability in various electrolytes. The aqueous and solid-state supercapacitors constructed using this composite supercapacitor material exhibit balanced performance, with the solid-state supercapacitor being particularly capable of providing long-term LED illumination, demonstrating strong practicality.

[0012] The composite supercapacitor material prepared by the method described in this invention includes amorphous molybdenum sulfide and silver. Silver has good conductivity (6.107 S / m), surface activity, and electroactivity among various conductive materials. Furthermore, the combination of silver and amorphous molybdenum sulfide can effectively improve the overall conductivity of the composite supercapacitor material, reduce internal resistance, promote charge transfer, and improve the electronic and electrochemical performance of the composite supercapacitor material. Therefore, the synergistic effect of the two can enable the composite supercapacitor material to have a large specific surface area and good conductivity, thereby improving the specific capacitance, energy density, and cycle stability of the supercapacitor.

[0013] Preferably, the potential of the first electrodeposition in step (1) is -1.2V to -1.5V, for example, it can be -1.2V, -1.3V, -1.4V or -1.5V, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] Preferably, the electrodeposition time in step (1) is 10 min to 40 min, for example, it can be 10 min, 15 min, 20 min, 25 min, 30 min, 35 min or 40 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] Preferably, in step (1) during the first electrodeposition, the foam metal substrate is used as the working electrode, the platinum wire is used as the counter electrode, and the saturated calomel electrode is used as the reference electrode.

[0016] Preferably, the sulfur-molybdenum source deposition solution in step (1) includes ammonium tetrathiomolybdate.

[0017] Preferably, the sulfur-molybdenum source deposition solution in step (1) also includes an auxiliary agent.

[0018] Preferably, the auxiliary agent includes potassium chloride.

[0019] Preferably, in the sulfur-molybdenum source deposition solution in step (1), the concentration of ammonium tetrathiomolybdate is 0.03 mol / L-0.08 mol / L, for example, it can be 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L or 0.08 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, in the sulfur-molybdenum source deposition solution in step (1), the concentration of the auxiliary agent is 8 mol / L-12 mol / L, for example, it can be 8 mol / L, 9 mol / L, 10 mol / L, 11 mol / L or 12 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] Preferably, the foamed metal substrate in step (1) comprises foamed nickel.

[0022] The use of nickel foam as described in this invention promotes electron transport, thereby increasing specific capacity, while avoiding the need for the addition of other additives.

[0023] Preferably, the foam metal substrate described in step (1) is first cleaned and dried before use.

[0024] Preferably, the cleaning agent used in the first cleaning includes acetone, ethanol, and deionized water.

[0025] Preferably, before step (2), the foam metal substrate loaded with amorphous molybdenum sulfide described in step (1) is first cleaned and dried a second time.

[0026] After the first electrodeposition in this invention, cleaning and drying were performed to provide a larger surface area for subsequent material loading.

[0027] Preferably, the second cleaning includes cleaning with deionized water and ethanol 3 to 5 times, for example, 3, 4 or 5 times.

[0028] Preferably, in step (2), the potential of the second electrodeposition is -0.8V to -1.1V, for example, it can be -0.8V, -0.9V, -1.0V or -1.1V, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, the second electrodeposition time in step (2) is 60s-360s, for example, it can be 60s, 120s, 180s, 240s, 300s or 360s, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] The potential and time of the second electrodeposition in this invention affect the deposition effect. If the potential of the second electrodeposition is too small, the driving force for silver ion reduction is insufficient, the deposition rate is extremely slow, and a continuous silver layer cannot be formed to achieve effective coating. If the potential of the second electrodeposition is too large, the reduction reaction is too violent, silver atoms rapidly nucleate and agglomerate, easily forming coarse silver particles or dendritic structures, resulting in uneven loading and damage to the original structure of molybdenum sulfide on the substrate, reducing electrode stability. If the time of the second electrodeposition is too short, the silver loading is insufficient, and a complete conductive network cannot be formed, the improvement in electronic conductivity of the composite electrode is limited, and the synergistic effect cannot be fully utilized. If the time of the second electrodeposition is too long, excessive silver growth will block the pore structure of the foam metal and hinder electrolyte penetration. At the same time, excessive silver will cover the active sites of molybdenum sulfide, resulting in a decrease in electrode specific capacitance.

[0031] Preferably, in step (2) during the second electrodeposition, the foam metal substrate loaded with amorphous molybdenum sulfide in step (1) is used as the working electrode, the platinum wire as the counter electrode, and the saturated calomel electrode as the reference electrode.

[0032] Preferably, the silver source deposition solution in step (2) includes a silver nitrate solution.

[0033] Preferably, the concentration of the silver source deposition solution in step (2) is 0.01 mol / L-0.05 mol / L, for example, it can be 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L or 0.05 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] The concentration of the silver source deposition solution in step (2) of this invention will affect the deposition effect. If the concentration of the silver source deposition solution is too low, the silver ion supply will be insufficient, the silver layer deposition amount will be low and it will be difficult to uniformly cover the substrate, and an effective conductive network will not be formed. If the concentration of the silver source deposition solution is too high, it will easily cause local concentration polarization, resulting in the agglomeration and growth of silver particles and uneven morphology. It will also easily cause the silver layer on the substrate surface to be too thick, covering the active sites of molybdenum sulfide and reducing the electrochemical performance of the electrode.

[0035] Preferably, after the second electrodeposition in step (2) is completed, the resulting composite supercapacitor material is further cleaned and dried for the third time.

[0036] Preferably, the third cleaning includes cleaning with deionized water and ethanol 3 to 5 times, for example, 3, 4 or 5 times.

[0037] In a second aspect, the present invention provides a composite supercapacitor material, which is prepared by the preparation method described in the first aspect.

[0038] The composite supercapacitor material described in this invention has abundant open space, which not only provides more electroactive sites, but also facilitates the diffusion of the deposition liquid during the electrochemical reaction process, thereby promoting the rapid diffusion of ions.

[0039] Thirdly, the present invention provides a supercapacitor comprising a composite supercapacitor material prepared by the preparation method described in the first aspect, or a composite supercapacitor material as described in the second aspect.

[0040] Preferably, the supercapacitor includes an aqueous supercapacitor and a solid-state supercapacitor.

[0041] Preferably, the aqueous supercapacitor includes a first anode, a first cathode, and an aqueous electrolyte, wherein the first anode and the first cathode each independently comprise the composite supercapacitor material.

[0042] Preferably, the solid-state supercapacitor includes a second anode, a second cathode, a separator (such as cellulose paper), and a gel electrolyte (such as PVA / KOH), wherein the second anode and the second cathode each independently comprise the composite supercapacitor material.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] This invention yields a silver-amorphous molybdenum sulfide-nickel foam metal material using a two-step electrodeposition method. The first step involves depositing molybdenum sulfide, followed by silver deposition in the second step. The preparation process is simple and controllable, requiring no high temperature or high pressure, and can be mass-produced. The resulting composite supercapacitor material exhibits a rich array of electroactive sites and rapid transport channels, resulting in a significant synergistic effect. It demonstrates high specific capacitance and good cycle stability in various electrolytes. The aqueous and solid-state supercapacitors constructed using this composite supercapacitor material exhibit balanced performance, with the solid-state supercapacitor being particularly capable of providing long-term LED illumination, making it highly practical. Attached Figure Description

[0045] Figure 1 The composite supercapacitor material (Ag / MoS) obtained in Example 1 of this invention x The composite supercapacitor material (MoS₂ / NF) obtained in Comparative Example 1 and the composite supercapacitor material obtained in Comparative Example 1 x XRD patterns of ( / NF).

[0046] Figure 2 The composite supercapacitor material (Ag / MoS) obtained in Example 1 of this invention x The composite supercapacitor material (MoS₂ / NF) obtained in Comparative Example 1 and the composite supercapacitor material obtained in Comparative Example 1 x Scanning electron microscope (SEM) images of / NF, where Figure 2 a is a scanning electron microscope image of the composite supercapacitor material obtained in Comparative Example 1. Figure 2 b、 Figure 2 c (magnification of 3000x) and Figure 2 d (magnification of 6000x) is a scanning electron microscope image of the composite supercapacitor material obtained in Example 1 at different magnifications.

[0047] Figure 3a The composite supercapacitor material (Ag / MoS) obtained in Example 1 of this invention x CV curves of / NF at different scan rates (10mV / s to 50mV / s) within the potential range of -0.5V to 0.5V.

[0048] Figure 3b The composite supercapacitor material (Ag / MoS) obtained in Example 1 of this invention x / NF) GCD curves for current densities ranging from 10 A / g to 25 A / g within a potential window from -0.5 V to 0.5 V.

[0049] Figure 3c The results show the cycle stability test results of the composite supercapacitor material (Ag / MoSx / NF) obtained in Example 1 of this invention.

[0050] Figure 4a This is a continuous charge-discharge cycle diagram of an aqueous symmetric supercapacitor prepared from the composite supercapacitor material obtained in Example 1 of the present invention.

[0051] Figure 4b Ragone diagram of a water-based symmetrical supercapacitor constructed using the composite supercapacitor material obtained in Example 1 as the positive and negative electrodes.

[0052] Figure 5a This is a graph showing the long-term cycling performance of a solid-state symmetric supercapacitor constructed using the composite supercapacitor material obtained in Example 1 as the positive and negative electrodes.

[0053] Figure 5b This is a graph showing the trend of power density variation of a solid-state symmetric supercapacitor constructed using the composite supercapacitor material obtained in Example 1 as the positive and negative electrodes.

[0054] Figure 6 This is a test image of a solid-state symmetric supercapacitor constructed using the composite supercapacitor material obtained in Example 1 as the positive and negative electrodes. Detailed Implementation

[0055] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0056] Example 1

[0057] This embodiment provides a method for preparing a composite supercapacitor material, the method comprising the following steps:

[0058] (1) Cut the nickel foam into 1cm×2cm pieces, and use acetone, ethanol and deionized water to ultrasonically clean for 10 minutes respectively to remove surface impurities. Then dry at 60℃ for 2 hours to obtain a clean nickel foam substrate.

[0059] (2) Disperse 5 mmol of ammonium tetrathiomolybdate and 1 mol of potassium chloride in 100 mL of ultrapure water and stir to prepare a sulfur-molybdenum source deposition solution. The concentration of ammonium tetrathiomolybdate in the sulfur-molybdenum source deposition solution is 0.05 mol / L and the concentration of potassium chloride is 10 mol / L.

[0060] (3) Using the three-electrode system of the CHI660E workstation, the nickel foam obtained in step (1) was immersed in the sulfur-molybdenum source deposition solution prepared in step (2) as the working electrode. Platinum wire and saturated calomel electrode were used as the counter electrode and reference electrode, respectively. A film of amorphous molybdenum sulfide loaded was deposited at a constant potential of -1.5V for 30 min to obtain a foam metal substrate loaded with amorphous molybdenum sulfide (named MoS). x / NF);

[0061] (4) Take the MoS obtained in step (3) x / NF was washed four times with deionized water and ethanol respectively, and then dried at 60°C for 2 hours.

[0062] (5) Disperse 2 mmol of silver nitrate in 100 mL of ultrapure water and stir to prepare a silver source deposition solution with a concentration of 0.02 mol / L;

[0063] (6) The MoS obtained in step (4) x / NF is the working electrode, platinum wire is the counter electrode, and saturated calomel reference electrode is the reference electrode. MoS x / NF is immersed in the silver source deposition solution prepared in step (5) and deposited at a constant potential of -1.0V for 300 seconds to achieve silver loading;

[0064] (7) The material prepared in step (6) is washed four times with deionized water and ethanol respectively, and then dried at 60°C for 2 hours to obtain the composite supercapacitor material (named Ag / MoS). x / NF).

[0065] Example 2

[0066] This embodiment provides a method for preparing a composite supercapacitor material, the method comprising the following steps:

[0067] (1) Cut the nickel foam into 1cm×2cm pieces, and use acetone, ethanol and deionized water to ultrasonically clean for 10 minutes respectively to remove surface impurities. Then dry at 60℃ for 2 hours to obtain a clean nickel foam substrate.

[0068] (2) Disperse 3 mmol of ammonium tetrathiomolybdate and 0.8 mol of potassium chloride in 100 mL of ultrapure water and stir to prepare a sulfur-molybdenum source deposition solution. The concentration of ammonium tetrathiomolybdate in the sulfur-molybdenum source deposition solution is 0.03 mol / L and the concentration of potassium chloride is 8 mol / L.

[0069] (3) Using the three-electrode system of CHI660E workstation, the foam nickel obtained in step (1) is immersed in the sulfur-molybdenum source deposition solution prepared in step (2) as the working electrode. Platinum wire and saturated calomel electrode are used as the counter electrode and reference electrode, respectively. A film of amorphous molybdenum sulfide loaded is deposited at a constant potential of -1.3V for 10min to obtain a foam metal substrate loaded with amorphous molybdenum sulfide.

[0070] (4) Take the MoS obtained in step (3) x / NF was washed three times with deionized water and ethanol respectively, and then dried at 60°C for 2 hours.

[0071] (5) Disperse 5 mmol of silver nitrate in 100 mL of ultrapure water and stir to prepare a silver source deposition solution with a concentration of 0.05 mol / L;

[0072] (6) Using the material obtained in step (4) as the working electrode, platinum wire as the counter electrode, and saturated calomel reference electrode as the reference electrode, the material obtained in step (4) is immersed in the silver source deposition solution prepared in step (5) and deposited at a constant potential of -1.0V for 300 seconds to achieve silver loading;

[0073] (7) The material prepared in step (6) is washed five times with deionized water and ethanol respectively, and then dried at 60°C for 2 hours to obtain the composite supercapacitor material.

[0074] Example 3

[0075] This embodiment provides a method for preparing a composite supercapacitor material, the method comprising the following steps:

[0076] (1) Cut the nickel foam into 1cm×2cm pieces, and use acetone, ethanol and deionized water to ultrasonically clean for 10 minutes respectively to remove surface impurities. Then dry at 60℃ for 2 hours to obtain a clean nickel foam substrate.

[0077] (2) Disperse 8 mmol of ammonium tetrathiomolybdate and 1.2 mol of potassium chloride in 100 mL of ultrapure water and stir to prepare a sulfur-molybdenum source deposition solution. The concentration of ammonium tetrathiomolybdate in the sulfur-molybdenum source deposition solution is 0.08 mol / L and the concentration of potassium chloride is 12 mol / L.

[0078] (3) Using the three-electrode system of CHI660E workstation, the foam nickel obtained in step (1) is immersed in the sulfur-molybdenum source deposition solution prepared in step (2) as the working electrode. Platinum wire and saturated calomel electrode are used as the counter electrode and reference electrode, respectively. A film of amorphous molybdenum sulfide loaded is deposited at a constant potential of -1.2V for 40min to obtain a foam metal substrate loaded with amorphous molybdenum sulfide.

[0079] (4) The material obtained in step (3) was washed 5 times with deionized water and ethanol respectively, and then dried at 60°C for 2 hours;

[0080] (5) Disperse 1 mmol of silver nitrate in 100 mL of ultrapure water and stir to prepare a silver source deposition solution with a concentration of 0.01 mol / L;

[0081] (6) Using the material obtained in step (4) as the working electrode, platinum wire as the counter electrode, and saturated calomel reference electrode as the reference electrode, the material obtained in step (4) is immersed in the silver source deposition solution prepared in step (5) and deposited at a constant potential of -1.0V for 300 seconds to achieve silver loading;

[0082] (7) The material prepared in step (6) is washed three times with deionized water and ethanol respectively, and then dried at 60°C for 2 hours to obtain the composite supercapacitor material.

[0083] Example 4

[0084] This embodiment provides a method for preparing a composite supercapacitor material. Except for step (6), in which a constant potential of -0.8V is deposited for 60 seconds, the preparation method is the same as in Example 1.

[0085] Example 5

[0086] This embodiment provides a method for preparing a composite supercapacitor material. Except for step (6), in which a constant potential of -0.9V is deposited for 120 seconds, the preparation method is the same as in Example 1.

[0087] Example 6

[0088] This embodiment provides a method for preparing a composite supercapacitor material. Except for step (6), in which a constant potential of -1.1V is deposited for 360 seconds, the preparation method is the same as in Example 1.

[0089] Example 7

[0090] This embodiment provides a method for preparing a composite supercapacitor material. Except for step (6), in which a constant potential of -0.6V is deposited for 300 seconds, the preparation method is the same as in Example 1.

[0091] Example 8

[0092] This embodiment provides a method for preparing a composite supercapacitor material. Except for step (6), in which a constant potential of -1.4V is deposited for 300 seconds, the preparation method is the same as in Example 1.

[0093] Example 9

[0094] This embodiment provides a method for preparing a composite supercapacitor material. Except for step (6), in which a constant potential of -1.0V is deposited for 30 seconds, the preparation method is the same as in Example 1.

[0095] Example 10

[0096] This embodiment provides a method for preparing a composite supercapacitor material. Except for step (6), in which a constant potential of -1.0V is deposited for 420 seconds, the preparation method is the same as in Example 1.

[0097] Example 11

[0098] This embodiment provides a method for preparing a composite supercapacitor material. Except for the concentration of the silver source deposition solution in step (5) being 0.005 mol / L, the preparation method is the same as in Example 1.

[0099] Example 12

[0100] This embodiment provides a method for preparing a composite supercapacitor material. Except for the concentration of the silver source deposition solution in step (5) being 0.08 mol / L, the preparation method is the same as in Example 1.

[0101] Comparative Example 1

[0102] This comparative example provides a method for preparing a composite supercapacitor material. The preparation method is identical to that of Example 1, except that steps (5)-(7) are omitted. The resulting composite supercapacitor material is named MoS₂. x / NF.

[0103] Comparative Example 2

[0104] This comparative example provides a method for preparing a composite supercapacitor material. The preparation method is the same as in Example 1 except that steps (5)-(7) are performed first, followed by steps (2)-(4), i.e., silver is loaded first and then amorphous molybdenum sulfide is loaded.

[0105] The composite supercapacitor material (Ag / MoS) obtained in Example 1 of this invention x The composite supercapacitor material (MoS₂ / NF) obtained in Comparative Example 1 and the composite supercapacitor material obtained in Comparative Example 1 x XRD patterns of / NF are as follows Figure 1 As shown, by Figure 1 The pink curve clearly shows three main typical diffraction peaks at 44.5°, 51.8°, and 76.4°, pointing to the (111), (200), and (220) planes of the NF crystal (JCPDS 87-0712), respectively; MoS xIn the crystalline phase, apart from the electron diffraction peak of NF, there are no other obvious electron diffraction peaks, indicating that it is an amorphous structure. Comparing the pink and blue curves in the XRD pattern, the obvious characteristic peaks at 38.12°, 64.45°, 77.41° and 81.55° can be indexed to the (111), (220), (311) and (222) planes of Ag (JCPDS 87-0717). The above results prove that Ag / MoS x Successful synthesis of / NF electrode material.

[0106] The composite supercapacitor material (Ag / MoS) obtained in Example 1 of this invention x The composite supercapacitor material (MoS₂ / NF) obtained in Comparative Example 1 and the composite supercapacitor material obtained in Comparative Example 1 x The scanning electron microscope image of / NF is as follows: Figure 2 As shown, where, Figure 2 a is a scanning electron microscope image of the composite supercapacitor material obtained in Comparative Example 1. Figure 2 b、 Figure 2 c and Figure 2 d is a scanning electron microscope image of the composite supercapacitor material obtained in Example 1 at different magnifications. Figure 2 a shows that the surface of the nickel foam substrate is completely covered by a uniform, continuous thin film, providing a larger surface area for subsequent Ag growth. From Figure 2 bc clearly shows that Ag / MoS x A typical multi-level structure is formed on the / NF surface, which consists of finer Ag nanounits (primary particles) assembling and agglomerating into uniformly sized spherical aggregates (secondary particles), and uniformly loaded onto MoS2. x The thin film surface. The presence of primary particles significantly increases the specific surface area of ​​the material, exposing more electrochemical active sites and thus improving the specific capacitance of the electrode. Meanwhile, secondary particles, acting as the reaction matrix, form a continuous conductive network through their tightly packed structure, effectively improving interfacial conductivity and promoting rapid charge transport. This multi-level structure of primary and secondary particles balances the number of active sites with charge transport efficiency, which is beneficial for improving electrochemical performance.

[0107] The cyclic voltammetry (CV) curve, galvanostatic charge-discharge (GCD) curve, and cycle stability curve of the composite supercapacitor material prepared in this invention were measured using an electrochemical workstation (CHI660E). During the test, the composite supercapacitor material prepared in Example 1, a platinum wire electrode, and a saturated calomel electrode were used as the working electrode, counter electrode, and reference electrode, respectively, thus forming a three-electrode test system. Its electrochemical performance was studied in a 2 mol / L potassium hydroxide electrolyte.

[0108] The composite supercapacitor material (Ag / MoS) obtained in Example 1 of this inventionx The CV curves of / NF at different scan rates (10mV / s~50mV / s) within the potential range of -0.5V to 0.5V are shown below. Figure 3a As shown. From Figure 3a As can be seen, the CV curves exhibit multiple distinct redox peaks within a scan rate range of 10-50 mV / s. This characteristic indicates that the electrode underwent a multi-step reversible Faraday redox reaction in the 2 mol / L KOH electrolyte, demonstrating a typical pseudocapacitive energy storage mechanism. Notably, the peak current increases synchronously with the increase of the scan rate, while the peak shape and the positions of the redox peaks maintain good consistency. This indicates that the electrode possesses good electrochemical activity at different scan rates, and that the charge transfer efficiency at the electrode-2 mol / L KOH electrolyte interface is high, with a very rapid kinetic response.

[0109] Figure 3b The composite supercapacitor material (Ag / MoS) obtained in Example 1 of this invention is presented. x GCD curves of / NF with current densities ranging from 5 A / g to 20 A / g within a potential window of -0.5 V to 0.5 V. From Figure 3b As can be seen, clear voltage plateaus appear in the curves, which correspond one-to-one with the redox peaks in the CV curves. This reflects the phased progression of the Faraday reaction during the charge-discharge process of the electrode in 2 mol / L KOH electrolyte, proving that the charge-discharge process is mainly dominated by reversible Faraday redox reactions, and fully demonstrating the high reversibility and high specific capacitance of the electrode. Furthermore, in 2 mol / L KOH electrolyte, the discharge time of the GCD curves decreases with increasing current density at different current densities, but the overall shape of the curves still maintains good symmetry. This indicates that the electrode can achieve efficient and reversible charge-discharge processes even at high current densities in 2 M KOH electrolyte, possessing excellent rate performance and power density.

[0110] Figure 3c The composite supercapacitor material (Ag / MoS) obtained in Example 1 of this invention x The results of the cyclic stability test of / NF are derived from... Figure 3c It can be seen that after 3000 consecutive charge-discharge cycles, the electrode material can still maintain 88.67% of the capacitance retention rate and the coulombic efficiency remains at 100%.

[0111] The Ag / MoS prepared in Example 1 x / NF composite electrode materials were used as the positive electrode (cathode) and negative electrode (anode), and then immersed in an electrolytic cell with 2 mol / L potassium hydroxide to construct an aqueous symmetric supercapacitor.

[0112] The practical application of supercapacitors requires a long cycle life. The continuous charge-discharge cycle diagram of the aqueous symmetric supercapacitor prepared from the composite supercapacitor material obtained in Example 1 of this invention is shown below. Figure 4a As shown, the device exhibits a significant capacitance retention of 88.15% after 3000 cycles and excellent coulombic efficiency (100%) during the test.

[0113] Figure 4b The diagram shows a ragone plot of a water-based symmetric supercapacitor constructed using the composite supercapacitor material obtained in Example 1 as the positive and negative electrodes. This device provides an energy density of 279.65 Wh / kg at a power density of 1028 W / kg, and maintains an energy density of 25.38 Wh / kg even at a higher power density of 10023 W / kg. This result is superior to most prior art technologies. Figure 4b (The values ​​other than those in the red curve) indicate that sulfide-based composite materials are superior.

[0114] The Ag / MoS prepared in Example 1 x A solid-state symmetric supercapacitor was constructed using / NF composite electrode materials as the positive and negative electrodes, PVA / KOH as the electrolyte, and cellulose paper as the separator.

[0115] The long-term cycling performance of solid-state symmetric supercapacitors was studied by repeating 3000 GCD tests, and the results are as follows: Figure 5a As shown, the device exhibits a 90.36% capacitance retention and a 100% coulombic efficiency after 3000 cycles.

[0116] To evaluate the practical application potential of solid-state symmetric supercapacitors Figure 5b The paper illustrates the trend of energy density versus power density of the device and compares it with the values ​​of representative sulfide-based electrode material supercapacitors in the prior art. It is clearly shown from the figure that the solid-state symmetric supercapacitor device of this invention can achieve a competitive power density of 541.93 W / kg at an energy density of 134.73 Wh / kg, outperforming existing devices. Figure 5b (Values ​​other than those in the blue curve).

[0117] Figure 6 This is a test image showing a solid-state symmetric supercapacitor constructed using the composite supercapacitor material obtained in Example 1 as the positive and negative electrodes. From... Figure 6 a, Figure 6 b and Figure 6As can be seen from c, the two series-connected solid-state symmetric supercapacitors can successfully light a blue 3.0 V LED: the blue light is bright in the initial stage, gradually weakens over time, is still relatively noticeable after 5 minutes, and still emits a faint blue light after 10 minutes, with a continuous lighting time of over 10 minutes. This result fully demonstrates that the solid-state symmetric supercapacitor assembled from this electrode material has stable and long-lasting energy storage and discharge performance, showing great application potential in the field of energy storage.

[0118] The specific capacitance and capacitance retention after 3000 cycles of the composite supercapacitor materials obtained in the above examples and Comparative Example 1 in a 2 mol / L KOH electrolytic solution at a current density of 5 A / g are shown in Table 1.

[0119] Table 1

[0120]

[0121] As can be seen from Table 1 above:

[0122] As shown in Example 1 and Comparative Example 1, the present invention, by loading amorphous molybdenum sulfide using an electrodeposition method followed by loading silver using an electrodeposition method, can improve the specific surface area and electronic conductivity of the supercapacitor material, thereby significantly improving the specific capacitance and cycle stability of the supercapacitor material. As shown in Example 1 and Comparative Example 2, the present invention uses a two-step electrodeposition method to first load amorphous molybdenum sulfide and then load silver, while Comparative Example 2 loads silver first and then amorphous molybdenum sulfide. Due to the high conductivity of silver, it preferentially covers the foamed nickel substrate, hindering the uniform deposition of molybdenum sulfide, resulting in the agglomeration of molybdenum sulfide particles, insufficient exposure of active sites, and weak interfacial bonding between silver and molybdenum sulfide, which is prone to peeling during charge-discharge cycles. This leads to a decrease in the specific surface area and electronic conductivity of the electrode, ultimately reducing the specific capacitance and cycle stability of the supercapacitor material. As shown in Example 1 and Examples 4-12, when loading silver in the second electrodeposition of the present invention, the potential, time, and concentration of the deposition solution all affect the deposition effect, thereby affecting the specific capacitance and cycle stability of the supercapacitor material.

[0123] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a composite supercapacitor material, characterized in that, The preparation method includes the following steps: (1) The foam metal substrate is immersed in the sulfur-molybdenum source deposition solution and the first electrodeposition is performed to obtain a foam metal substrate loaded with amorphous molybdenum sulfide; (2) Immerse the foam metal substrate loaded with amorphous molybdenum sulfide described in step (1) into the silver source deposition solution and perform a second electrodeposition to obtain the composite supercapacitor material, wherein the composite supercapacitor material includes a foam metal substrate loaded with amorphous molybdenum sulfide and silver.

2. The preparation method according to claim 1, characterized in that, Step (1) The potential of the first electrodeposition is -1.2V to -1.5V; Preferably, the time for the first electrodeposition in step (1) is 10 min to 40 min; Preferably, in step (1) during the first electrodeposition, the foam metal substrate is used as the working electrode, the platinum wire is used as the counter electrode, and the saturated calomel electrode is used as the reference electrode.

3. The preparation method according to claim 1 or 2, characterized in that, The sulfur-molybdenum source deposition solution in step (1) includes ammonium tetrathiomolybdate; Preferably, the sulfur-molybdenum source deposition solution in step (1) further includes an auxiliary agent; Preferably, the auxiliary agent includes potassium chloride; Preferably, in the sulfur-molybdenum source deposition solution in step (1), the concentration of ammonium tetrathiomolybdate is 0.03 mol / L-0.08 mol / L; Preferably, in the sulfur-molybdenum source deposition solution in step (1), the concentration of the auxiliary agent is 8 mol / L-12 mol / L.

4. The preparation method according to claim 3, characterized in that, The foamed metal substrate in step (1) includes foamed nickel; Preferably, the foamed metal substrate described in step (1) is first cleaned and dried before use; Preferably, the cleaning agent used in the first cleaning includes acetone, ethanol, and deionized water.

5. The preparation method according to claim 1 or 2, characterized in that, Before proceeding to step (2), the foam metal substrate loaded with amorphous molybdenum sulfide described in step (1) is first cleaned and dried a second time. Preferably, the second cleaning includes cleaning with deionized water and ethanol 3 to 5 times respectively.

6. The preparation method according to claim 1 or 2, characterized in that, In step (2), the potential for the second electrodeposition is -0.8V to -1.1V; Preferably, the time for the second electrodeposition in step (2) is 60s-360s; Preferably, in step (2) during the second electrodeposition, the foam metal substrate loaded with amorphous molybdenum sulfide in step (1) is used as the working electrode, the platinum wire as the counter electrode, and the saturated calomel electrode as the reference electrode.

7. The preparation method according to claim 1 or 2, characterized in that, The silver source deposition solution in step (2) includes a silver nitrate solution; Preferably, the concentration of the silver source deposition solution in step (2) is 0.01 mol / L to 0.05 mol / L; Preferably, after the second electrodeposition in step (2) is completed, the obtained composite supercapacitor material is further cleaned and dried for the third time; Preferably, the third cleaning includes cleaning with deionized water and ethanol 3 to 5 times respectively.

8. A composite supercapacitor material, characterized in that, The composite supercapacitor material is prepared by the preparation method described in any one of claims 1-7.

9. A supercapacitor, characterized in that, The supercapacitor includes a composite supercapacitor material prepared by any one of the preparation methods described in claims 1-7, or a composite supercapacitor material as described in claim 8.

10. The supercapacitor according to claim 9, characterized in that, The supercapacitors include aqueous supercapacitors and solid-state supercapacitors; Preferably, the aqueous supercapacitor includes a first anode, a first cathode, and an aqueous electrolyte, wherein the first anode and the first cathode each independently comprise the composite supercapacitor material; Preferably, the solid-state supercapacitor includes a second anode, a second cathode, a separator, and a gel electrolyte, wherein the second anode and the second cathode each independently comprise the composite supercapacitor material.

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