In-situ ag-doped high-entropy ldh supercapacitor electrode material for constructing conductive network and preparation method and application thereof

Abstract

This invention provides a high-entropy LDH supercapacitor electrode material with an in-situ Ag-doped conductive network, its preparation method, and its applications. Through a unique design of "high-entropy matrix activation, in-situ construction of a conductive network using Ag nanoparticles / nanowires, and multiple synergistic enhancements," this material overcomes the bottlenecks of poor intrinsic conductivity, metal ion dissolution, and insufficient cycle stability of traditional high-entropy electrode materials. It exhibits unique advantages in ultra-high specific capacitance, rate performance, and cycle stability, providing a highly promising material solution for the development of next-generation high-performance supercapacitors.

Description

Technical Field

[0001] This invention belongs to the field of energy storage, specifically relating to an electrode material for a high-entropy LDH supercapacitor with an in-situ Ag-doped conductive network and its preparation method. Background Technology

[0002] Existing technologies for low-dimensional, high-entropy layered hydrogen hydroxide (LDH) materials primarily involve constructing a high configurational entropy system containing five or more transition metals (such as Fe, Co, Ni, Mn, Zn, Cu, and Cr), and then employing methods such as one-pot co-precipitation, MOF-mediated synthesis, electrodeposition, or hydrothermal / solvothermal processes to prepare the materials. Among these, cutting-edge technologies such as plasma-assisted hydrothermal methods hold promise for achieving synergistic breakthroughs in both precise microstructure control and large-scale production.

[0003] In terms of morphology and performance optimization, existing technologies increase active sites and shorten transport paths by designing low-dimensional structures such as ultrathin nanosheets, hierarchical three-dimensional microspheres, heterojunctions, and amorphous structures. Simultaneously, defect engineering (such as metal cation leaching, acid etching, and high-valence metal induction) and composite modification (loading noble metals or conductive substrates) further enhance catalytic activity and stability. These strategies have enabled low-dimensional high-entropy LDH materials to demonstrate excellent application prospects in fields such as electrocatalytic water splitting (OER / HER), zinc-air batteries, and biomedicine. Currently, high-entropy layered double hydroxides (HE-LDHs), as electrode materials for supercapacitors, although theoretically possessing high specific capacity, still face four core challenges in practical applications: poor intrinsic conductivity, poor cycle stability, insufficient utilization of active sites, and limitations of existing synthesis methods. Among these, the poor intrinsic conductivity of high-entropy electrodes is their most fundamental weakness: the layered structure restricts the rapid transport of electrons within the material, leading to a sharp decline in performance at high rates (i.e., poor rate performance), making it difficult to meet the high-power output requirements of supercapacitors. In practical applications, poor conductivity can increase the internal resistance of the electrode, leading to energy loss and heat generation. Insufficient cycle stability: During charge and discharge, high-entropy electrodes experience material detachment after repeated charge and discharge cycles due to factors such as the dissolution of some transition metal ions and insufficient bonding between the active material and the conductive substrate. High-entropy hydroxides are prone to volume expansion during electrochemical reactions, and when used as electrode materials, their inherently poor conductivity and insufficient structural stability make it difficult to simultaneously achieve high specific capacitance, excellent rate performance, and long cycle life.

[0004] Based on this, this invention proposes a low-cost, binder-free, in-situ Ag-doped low-dimensional high-entropy LDH supercapacitor electrode material prepared on nickel foam. This material overcomes the bottlenecks of poor intrinsic conductivity, metal ion dissolution, and insufficient cycle stability of traditional high-entropy electrode materials through a unique design of "high-entropy matrix activation, in-situ construction of a conductive network by Ag nanoparticles / nanowires, and multiple synergistic enhancements." It exhibits unique advantages in ultra-high specific capacitance, rate performance, and cycle stability, providing a highly promising material solution for the development of next-generation high-performance supercapacitors. Summary of the Invention

[0005] The purpose of this invention is to overcome the technical defects of existing high-entropy layered hydrogen hydroxide (LDH) supercapacitor electrode materials, such as poor intrinsic conductivity, easy dissolution of metal ions during charge and discharge leading to insufficient cycle stability, and poor rate performance. The invention aims to provide a low-cost, binder-free electrode material that combines ultra-high specific capacitance, excellent rate performance, and ultra-long cycle stability. Existing technologies suffer from the following drawbacks: ① Poor conductivity: The layered structure of high-entropy LDH restricts electron transport, resulting in a sharp capacity decay during high-power charge and discharge. ② Poor cycle stability: Irreversible dissolution of transition metal ions during electrochemical cycling causes loss of active material and structural collapse. ③ Complex electrode fabrication process: Traditional coating methods use binders to increase interfacial resistance and "dead volume," and it is difficult to achieve efficient electronic contact between the active material and the current collector.

[0006] The core advantages of this invention are as follows: ① Low-cost, binder-free in-situ preparation process: Direct growth on nickel foam avoids the "dead volume" and additional interfacial resistance caused by the use of binders in traditional coating methods, simplifies the electrode manufacturing process, reduces costs, and ensures close contact and efficient electron transport between the active material and the current collector.

[0007] ②In-situ construction of a three-dimensional conductive network using Ag nanostructures: Ag nanoparticles / nanowires are uniformly distributed in the LDH matrix, forming a "high-speed conductive path" that runs through the electrode. This fundamentally solves the bottleneck of poor intrinsic conductivity in high-entropy LDHs, thereby significantly improving the rate performance (capacity retention at high power) of the material.

[0008] ③ High-entropy matrix activation: The high-entropy effect of multi-metal elements provides abundant reactive sites.

[0009] ④Ag inhibits metal ion dissolution: The introduction of Ag can stabilize the LDH layer structure, effectively inhibit the irreversible dissolution of transition metal ions during charging and discharging, and greatly enhance cycle stability.

[0010] ⑤ An appropriate amount of SDS induces the formation of an interlaced flower-like structure of ultrathin nanosheets, which, together with silver nanowires, constructs a three-dimensional open network rich in mesopores and macropores, providing a high specific surface area, fully exposing active sites and promoting rapid diffusion of electrolyte ions.

[0011] ⑥ The synthesized NiCoFeCuAg-LDH electrode exhibits ultra-high sheet capacitance, energy density, and excellent cycling stability.

[0012] To achieve the above objectives, the present invention adopts the following technical solution: This invention solves the above problems simultaneously through an integrated design of "constructing a conductive network with in-situ Ag nanostructures + low-dimensional high-entropy LDH matrix + in-situ growth on nickel foam".

[0013] An electrode material for a low-dimensional, high-entropy LDH supercapacitor with an in-situ Ag-doped conductive network comprises an LDH matrix formed by five metallic elements: Ni, Co, Fe, Cu, and Ag, and Ag nanoparticles / nanowires generated by in-situ reduction. The Ag nanoparticles / nanowires are dispersed between the LDH sheets, forming a three-dimensional conductive network. The electrode material has a flower-like structure with interlaced ultrathin nanosheets, and mesopores and macropores are distributed between the sheets.

[0014] A method for preparing a low-dimensional high-entropy LDH electrode material with an in-situ Ag-doped conductive network includes the following steps: (a) Dissolve nickel salt, cobalt salt, iron salt, copper salt, and silver salt in water in a certain proportion, add surfactant SDS, and stir until homogeneous; (b) The resulting solution and the nickel foam substrate were transferred together into a hydrothermal reactor and reacted at 120-200°C for 6-24 hours; (c) After the reaction is complete, the material is cleaned and dried to obtain the NiCoFeCuAg-LDH electrode material loaded on nickel foam.

[0015] Preferably, the molar ratio of the nickel, cobalt, iron, copper and silver salts is 1:1:1:1:1.

[0016] Preferably, the amount of SDS used is 0.1-0.5 g, more preferably 0.2 g.

[0017] Preferably, the hydrothermal temperature is 160°C and the time is 12 hours.

[0018] The advantages of this invention are: (1) Synergistic effect of high-entropy LDH components Simultaneously, five metallic elements—Ni, Co, Fe, Cu, and Ag—are introduced to provide abundant electrochemical active sites and enhance the structural stability of the material by utilizing the electronic interactions and lattice distortion effects between multiple metals.

[0019] (2) In-situ Ag doping to construct a three-dimensional conductive network Partial Ag during hydrothermal process + In situ reduction to Ag nanoparticles and nanowires, uniformly dispersed between LDH sheets, forming an embedded three-dimensional conductive network, achieving nanoscale close contact between the conductive phase and the active phase, significantly reducing interfacial resistance; at the same time, Ag nanowires serve as a framework support, suppressing volume expansion and structural collapse, and improving cycling stability.

[0020] (3) One-step hydrothermal in-situ growth, simple process and no binder required LDH growth and Ag are completed simultaneously in a single hydrothermal reaction. + The reduction and conductive network is constructed and directly loaded onto the nickel foam substrate to form an integrated binder-free electrode, avoiding the dead volume and additional resistance in traditional coating processes, and improving the utilization rate and rate performance of active materials.

[0021] (4) Multi-level porous structure controlled by SDS soft template An appropriate amount of SDS (0.2 g) induces the formation of a flower-like structure of interlaced ultrathin nanosheets, which, together with silver nanowires, constructs a three-dimensional open network rich in mesopores and macropores, providing a high specific surface area, fully exposing active sites and promoting rapid diffusion of electrolyte ions.

[0022] (5) Excellent comprehensive electrochemical performance A. Ultra-high surface capacitance: 44.94 F / cm 2 ; B. Good rate performance: 20 → 100 mA / cm 2 The specific capacitance decreased from 10.99 to 5.56 F / cm. 2 It maintains a high capacity even at high power; C. Excellent cycling stability: 100 mA / cm 2 After 10,000 cycles, the capacity retention rate is 89%. D. High energy / power density: Power density 13.99 mW / cm³ 2 Energy density at hourly rate: 2.99 mWh / cm³ 2 69.94 mW / cm 2 It still reaches 1.51 mWh / cm³. 2 . Attached Figure Description

[0023] Figure 1Electron micrographs of NiCoFeCuAg samples with different SDS concentrations: (a) NiCoFeCuAg-0 (Example 1); (b) NiCoFeCuAg-0.1 (Example 2); (c) NiCoFeCuAg-0.2 (Example 3); (d) NiCoFeCuAg-0.3 (Example 4); (e) NiCoFeCuAg-0.4 (Example 5); (f) NiCoFeCuAg-0.5 (Example 6). Figure 2 EDS energy dispersive spectroscopy and elemental distribution of NiCoFeCuAg-0.2 (Example 3): (a) Selected area electron microscope image, (bf) Elemental distribution diagrams of Ni, Co, Fe, Cu and Ag in sequence, (g) EDS spectrum; Figure 3 The XRD pattern of NiCoFeCuAg-0.2 (Example 3); Figure 4 Transmission electron microscope images of NiCoFeCuAg-0.2 (Example 3): (a) low magnification image, (b) high magnification image; Figure 5 XPS spectra of NiCoFeCuAg-0.2 (Example 3): (a) full spectrum, (b) C 1s, (c) O 1s, (d) Ni 2p, (e) Co 2p, (f) Fe 2p, (g) Cu 2p, (h) Ag 3d; Figure 6 Electrochemical performance of NiCoFeCuAg-0 (Example 1), NiCoFeCuAg-0.1 (Example 2), NiCoFeCuAg-0.2 (Example 3), and NiCoFeCuAg-0.3 (Example 4): (a) CV curve at 10 mV / s, (b) CV curve at 10 mA / cm². 2 (c) GCD test curve, (d) EIS curve, (e) rate characteristics; Figure 7 Sheet capacitance characteristics of NiCoFeCuAg-0.2 (Example 3) electrode Figure 8 Electrochemical performance of the asymmetric supercapacitor (NiCoFeCuAg-0.2 / / AC) assembled with NiCoFeCuAg-0.2 and activated carbon (AC) in Example 3: (a) CV curves of NiCoFeCuAg-0.2 and AC electrode materials at 10 mV / s, (b) CV curves at 10 mV / s in different voltage ranges, (c) GCD curves at different current densities, (d) Rate capability curves of the device, (e) 100 mA / cm² 2Cyclic stability under charge-discharge conditions, (f) FESEM image of Example 3 after 10,000 charge-discharge cycles; Figure 9 Energy density versus power density (EP) curves for the asymmetric supercapacitor (NiCoFeCuAg-0.2 / / AC) assembled in Example 3. Detailed Implementation

[0024] To make the above-mentioned features and advantages of the present invention more apparent and understandable, specific embodiments are described below in detail. Unless otherwise specified, the methods of the present invention are conventional methods in the art. Example 1

[0025] Preparation of NiCoFeCuAg-LDH Weigh out 1 mmol each of ferric chloride, copper nitrate, cobalt chloride, silver nitrate, and nickel nitrate sequentially, dissolve them in 25 ml of deionized water, sonicate for 5 min until the drugs are completely dissolved and stirred until uniformly dispersed, then transfer the resulting solution together with cleaned nickel foam (2 × 3 cm) into a 50 ml reaction vessel and place it at 160°C. ° The reaction was carried out hydrothermally in an oven at C for 12 hours. After the reaction was completed, the mixture was washed with deionized water and ethanol, and then dried at 70°C. ° NiCoFeCuAg-LDH was obtained by drying in an oven at C for 24 h and labeled as NCFCA-0. Example 2

[0026] Preparation of NiCoFeCuAg-LDH Weigh out 1 mmol each of ferric chloride, copper nitrate, cobalt chloride, silver nitrate, and nickel nitrate sequentially, dissolve them in 25 ml of deionized water, sonicate for 5 min until the drugs are completely dissolved, add 0.1 g of SDS, stir until uniformly dispersed, and transfer the resulting solution together with the cleaned nickel foam (2 × 3 cm) into a 50 ml reaction vessel, place at 160°C. ° The reaction was carried out hydrothermally in an oven at C for 12 hours. After the reaction was completed, the mixture was washed with deionized water and ethanol, and then dried at 70°C. ° NiCoFeCuAg-LDH was obtained by drying in an oven at C for 24 h and labeled as NCFCA-0.1. Example 3

[0027] Preparation of NiCoFeCuAg-LDH Weigh out 1 mmol each of ferric chloride, copper nitrate, cobalt chloride, silver nitrate, and nickel nitrate sequentially, dissolve them in 25 ml of deionized water, sonicate for 5 min until the drugs are completely dissolved, add 0.2 g of SDS, stir until uniformly dispersed, and transfer the resulting solution together with the cleaned nickel foam (2 × 3 cm) into a 50 ml reaction vessel, and place it at 160°C.° The reaction was carried out hydrothermally in an oven at C for 12 hours. After the reaction was completed, the mixture was washed with deionized water and ethanol, and then dried at 70°C. ° NiCoFeCuAg-LDH was obtained by drying in an oven at C for 24 h and labeled as NCFCA-0.2. Example 4

[0028] Preparation of NiCoFeCuAg-LDH Weigh out 1 mmol each of ferric chloride, copper nitrate, cobalt chloride, silver nitrate, and nickel nitrate sequentially, dissolve them in 25 ml of deionized water, sonicate for 5 min until the drugs are completely dissolved, add 0.3 g of SDS, stir until uniformly dispersed, and transfer the resulting solution together with the cleaned nickel foam (2 × 3 cm) into a 50 ml reaction vessel, place at 160°C. ° The reaction was carried out hydrothermally in an oven at C for 12 hours. After the reaction was completed, the mixture was washed with deionized water and ethanol, and then dried at 70°C. ° NiCoFeCuAg-LDH was obtained by drying in an oven at C for 24 h and labeled as NCFCA-0.3. Example 5

[0029] Preparation of NiCoFeCuAg-LDH Weigh out 1 mmol each of ferric chloride, copper nitrate, cobalt chloride, silver nitrate, and nickel nitrate sequentially, dissolve them in 25 ml of deionized water, sonicate for 5 min until the drugs are completely dissolved, add 0.4 g of SDS, stir until uniformly dispersed, and transfer the resulting solution together with the cleaned nickel foam (2 × 3 cm) into a 50 ml reaction vessel, place it at 160°C. ° The reaction was carried out hydrothermally in an oven at C for 12 hours. After the reaction was completed, the mixture was washed with deionized water and ethanol, and then dried at 70°C. ° NiCoFeCuAg-LDH was obtained by drying in an oven at C for 24 h and labeled as NCFCA-0.4. Example 6

[0030] Preparation of NiCoFeCuAg-LDH Weigh out 1 mmol each of ferric chloride, copper nitrate, cobalt chloride, silver nitrate, and nickel nitrate sequentially, dissolve them in 25 ml of deionized water, sonicate for 5 min until the drugs are completely dissolved, add 0.5 g of SDS, stir until uniformly dispersed, and transfer the resulting solution together with the cleaned nickel foam (2 × 3 cm) into a 50 ml reaction vessel, place it at 160°C. ° The reaction was carried out hydrothermally in an oven at C for 12 hours. After the reaction was completed, the mixture was washed with deionized water and ethanol, and then dried at 70°C. ° NiCoFeCuAg-LDH was obtained by drying in an oven at C for 24 h and labeled as NCFCA-0.5.

[0031] Electrochemical property measurement:

[0032] The performance of the synthesized samples was evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The specific capacitance of the electrode was calculated from the GCD curve using formula (1):

[0033] in C A Area capacitance (F / cm) 2 ); I The discharge current is (A). S The geometric area of ​​the electrode (cm²) 2 );Δ V The potential difference during the discharge time ( V );Δ t The discharge time (s) of the GCD curve.

[0034] An asymmetric supercapacitor (ASC) device was constructed using the product of Example 3 as the positive electrode and activated carbon (AC) as the negative electrode. The AC negative electrode was prepared by mixing activated carbon, acetylene black, and polytetrafluoroethylene (PTFE) in a mass ratio of 8:1:1, then bonding it to nickel foam and drying it in air at 80°C for 10 h. Finally, the positive and negative electrodes in the ASC device were separated by cellulose-based filter paper, and a 2 M KOH aqueous solution was used as the electrolyte. The surface energy density (Ea) of the asymmetric supercapacitor (ASC) device was [not specified]. A mWh / cm 2 ) and surface power density (P A mW / cm 2 The calculations for ) are performed according to formulas (2) and (3) respectively:

[0035]

[0036] In the formula, C A Area capacitance (F / cm) 2 The specific capacitance Δ is calculated based on the ACS discharge curve. V ( V ) represents the potential window, Δ t (s) represents the discharge time.

[0037] Figures 1-5 Characterization of the morphology and microstructure of the product:

[0038] Figure 1The synthesized NiCoFeCuAg-0 (Example 1) is as follows: Figure 1 As shown in (a); the synthesized NiCoFeCuAg-0.1 (Example 2) is as follows. Figure 1 As shown in (b); the synthesized NiCoFeCuAg-0.2 (Example 3) is as follows. Figure 1 As shown in (c); the synthesized NiCoFeCuAg-0.3 (Example 4) is as follows. Figure 1 As shown in (d); the synthesized NiCoFeCuAg-0.4 (Example 5) is as follows. Figure 1 As shown in (e); the synthesized NiCoFeCuAg-0.5 (Example 6) is as follows. Figure 1 As shown in (f).

[0039] Without SDS, NCFCA-0 exhibits a large particle morphology. With 0.1 g of SDS, NCFCA-0.1 forms a small-sized nanosheet flower-like structure, but the sheets are thick and stacked, limiting porosity and specific surface area. This is attributed to insufficient SDS, weak soft template induction ability, and inadequate crystallization regulation. When SDS increases to 0.2 g, NCFCA-0.2 shows a large number of interwoven ultrathin nanosheets stacked together, with silver nanowires uniformly distributed between the sheets, forming a rich mesoporous / macroporous conductive network. This significantly improves specific surface area and ion transport capacity, making it a key structure for achieving excellent electrochemical performance. With 0.3 g of SDS, although NCFCA-0.3 still contains silver nanowires, its morphology deteriorates, with severe sheet adhesion, disordered stacking, local collapse of the porous structure, and decreased pore connectivity. When the SDS content was 0.4 g and 0.5 g, the ordered morphology of NCFCA-0.4 and NCFCA-0.5 was destroyed. This was because the excessive SDS formed high-concentration micelles, which interfered with the ordered nucleation and growth of LDH. The residual organic matter aggravated the aggregation of the lamellar structures, resulting in a significant decrease in the exposure of effective active sites and ion transport efficiency.

[0040] Figure 2 The EDS energy spectrum and elemental distribution of NiCoFeCuAg-0.2 (Example 3) are shown. The EDS energy spectrum and elemental distribution diagram show that the product mainly consists of Ni, Co, Fe, Cu, and Ag elements.

[0041] Figure 3 The XRD pattern of NiCoFeCuAg-0.2 (Example 3) is shown. The diffraction pattern reveals that the product mainly consists of NiFe-LDH (PDF#00-033-0429) and Cu2(OH)3Cl (PDF#97-026-0350) phases. Furthermore, NiCoFeCuAg-0.2 shows a high XRD pattern at 38.1°C. ° 44.3 ° 64.4 ° and 77.4 °A strong diffraction peak also appeared, which was attributed to elemental Ag (PDF#98-000-0398), indicating that during the hydrothermal reaction, Ag... + In-situ reduction occurs, generating Ag nanoparticles and nanowires that are dispersed in the LDH matrix, thereby forming a three-dimensional conductive network in situ.

[0042] Figure 4 (a) is a low-magnification transmission electron microscope (TEM) image of NiCoFeCuAg-0.2 (Example 3); (b) is a high-magnification TEM image.

[0043] Low-magnification images revealed that the sample exhibited a typical ultrathin, wrinkled LDH nanosheet morphology, with the layers stacked on top of each other, consistent with the morphology observed in the SEM images. High-resolution images showed clear lattice fringes, with interplanar spacings of 0.230 nm and 0.197 nm corresponding to the (0 1 5) and (0 1 8) crystal planes of NiFe-LDH, respectively, and an interplanar spacing of 0.204 nm corresponding to the (2 0 0) crystal plane of Ag.

[0044] Figure 5 XPS spectra of NiCoFeCuAg-0.2 (Example 3): (a) full spectrum, (b) C 1s, (c) O 1s, (d) Ni 2p, (e) Co 2p, (f) Fe 2p, (g) Cu 2p, (h) Ag 3d.

[0045] Figure 5 The middle (a) spectrum shows that the product is composed of C, O, Ni, Co, Fe, Cu and Ag elements. Figure 5 (b) shows the C 1s spectrum, with peaks at binding energies of 284.81 eV, 285.88 eV, 287.29 eV, and 288.64 eV corresponding to C=C, CO, C=O, and CO32 bonds, respectively. 2- . Figure 5 (c) corresponds to the O 1s spectrum. The peak at a binding energy of 531.95 eV corresponds to the MO bond, and the peak at a binding energy of 533.62 eV corresponds to the OH bond, indicating adsorbed oxygen (O). w The peak of ) is located at 535.22 eV, with OH accounting for the highest proportion, confirming that the layered structure of LDH provides sufficient sites for charge transfer and storage. Figure 5 The spectrum (d) is that of Ni 2p. 3 / 2 The peak is located at 855.38 eV, Ni 2p 1 / 2 The peak is located at 875.88 eV, and there are obvious satellite peaks at the binding energies of 863.08 eV and 881.23 eV, which confirms that Ni is the main metal ion involved in the construction of the LDH layer framework. Figure 5The middle (e) spectrum is the Co 2p spectrum. Co 2p 3 / 2 At 784.53 eV (Co 2+ ) and 782.03 eV (Co 3+ ), Co 2p 1 / 2 Corresponding to 799.36 eV (Co 2+ ) and 797.73 eV (Co 3+ ), accompanied by satellite peaks of 789.11 eV and 806.10 eV. Co 2+ / Co 3+ Mixed valence states generate abundant electronic defects, promote electron transport, and enhance redox reaction kinetics. Figure 5 The spectrum in (f) is for Fe 2p, and the peak at 707.44 eV, which binds to Fe 2p, is attributed to Fe 2p. 3 / 2 The peak at 723.26 eV is attributed to Fe 2p. 1 / 2 The peak at 713.98 eV corresponds to Fe-OH. Figure 5 (g) is the spectrum of Cu 2p, Cu + The peaks corresponding to the binding energies of Cu at 935.25 eV and 952.62 eV are... 2+ The peaks corresponding to the binding energies of Cu at 938.09 eV and 957.12 eV are... + and Cu 2+ The presence of redox pairs effectively promotes charge separation and transport. Figure 5 (h) represents the spectrum of Ag 3d, Ag + The peaks corresponding to the binding energies of 368.79 eV and 374.30 eV are for the NiCoFeCuAg-0.2 sample, while those for the Ag element are at 369.56 eV and 375.51 eV. XPS characterization results indicate the successful synthesis of the NiCoFeCuAg-0.2 sample.

[0046] Figures 6-9 Electrochemical characteristics of the product:

[0047] Figure 6 Electrochemical performance of NiCoFeCuAg-0 (Example 1), NiCoFeCuAg-0.1 (Example 2), NiCoFeCuAg-0.2 (Example 3), and NiCoFeCuAg-0.3 (Example 4): (a) CV curve at 10 mV / s, (b) CV curve at 10 mA / cm². 2 (c) GCD test curve, (d) EIS curve, (e) rate characteristics.

[0048] Based on the CV closing area and GCD discharge duration, it can be seen that NiCoFeCuAg-0.2 (Example 3) has the largest surface capacitance. At 10 mA / cm²...2 The surface capacitance of NiCoFeCuAg-0 (Example 1) is 6.676 F / cm. 2 The surface capacitance of NiCoFeCuAg-0.1 (Example 2) is 16.51 F / cm. 2 The surface capacitance of NiCoFeCuAg-0.2 (Example 3) is 44.94 F / cm. 2 The surface capacitance of NiCoFeCuAg-0.3 (Example 4) is 22.59 F / cm. 2 At 50 mA / cm 2 At this temperature, NiCoFeCuAg-0.2 (Example 3) still has 28.06 F / cm³. 2 The surface capacitance is 8.18 times that of NiCoFeCuAg-0 (Example 1).

[0049] Figure 7 The surface capacitance characteristics of the NiCoFeCuAg-0.2 (Example 3) electrode are shown. At a current density of 10 mA / cm², 2 At that time, the surface capacitance was 44.94 F / cm. 2 At 50 mA / cm 2 Below, NiCoFeCuAg-0.2 (Example 3) has a strength of 28.06 F / cm. 2 The capacitance ratio is 62.4%.

[0050] Figure 8 Electrochemical performance of the asymmetric supercapacitor (NiCoFeCuAg-0.2 / / AC) assembled with NiCoFeCuAg-0.2 and activated carbon (AC) in Example 3: (a) CV curves of NiCoFeCuAg-0.2 and AC electrode materials at 10 mV / s, (b) CV curves at 10 mV / s in different voltage ranges, (c) GCD curves at different current densities, (d) Rate capability curves of the device, (e) 100 mA / cm² 2 Cyclic stability under charge-discharge conditions, (f) FESEM image of Example 3 after 10,000 charge-discharge cycles.

[0051] It can be observed that the device has a stable operating window of 0–1.4 V, and its charge and discharge are highly reversible. This is observed at current densities of 20, 40, 60, 80, and 100 mA / cm². 2 At those times, the specific capacitances of the supercapacitors were 10.99, 8.66, 7.46, 6.47, and 5.56 F / cm, respectively. 2 Even at high current densities, the device maintains good specific capacity output, indicating that the material can be applied to high-power energy storage scenarios. The device operates at 100 mA / cm². 2At current densities exceeding the specified limits, the NiCoFeCuAg-0.2 / / AC supercapacitor retained 89% of its capacity after 10,000 charge-discharge cycles, indicating that the in-situ Ag-doped three-dimensional electrode network significantly improved the device's structural stability and cycle life. FESEM images of the NiCoFeCuAg-0.2 / / AC device after 10,000 GCD charge-discharge cycles showed that the NiCoFeCuAg-0.2 morphology was stable, with no obvious structural collapse or pulverization.

[0052] Figure 9 The energy density versus power density (EP) curves for the asymmetric supercapacitor (NiCoFeCuAg-0.2 / / AC) assembled in Example 3 are shown. The power density is 13.99 mW / cm². 2 At that time, the energy density can reach 2.99 mWh / cm³. 2 When the power density is increased to 69.94 mW / cm² 2 At that time, the energy density remained at 1.51 mWh / cm³. 2 This indicates that the output characteristics exceed both power density and energy density during this period.

[0053] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A high-entropy LDH supercapacitor electrode material with an in-situ Ag-doped conductive network, characterized in that: The electrode material comprises an LDH matrix formed by five metallic elements: Ni, Co, Fe, Cu, and Ag, and Ag nanoparticles / nanowires generated by in-situ reduction. The Ag nanoparticles / nanowires are dispersed between the LDH sheets to form a three-dimensional conductive network. The electrode material has a flower-like structure with ultrathin nanosheets stacked in an interlaced manner, and mesopores and macropores are distributed between the sheets.

2. The method for preparing the electrode material according to claim 1, characterized in that, Includes the following steps: (a) Dissolve nickel salt, cobalt salt, iron salt, copper salt, and silver salt in water in a certain proportion, add surfactant SDS, and stir until homogeneous; (b) The resulting solution and the nickel foam substrate were transferred together into a hydrothermal reactor and reacted at 120-200°C for 6-24 hours; (c) After the reaction is complete, the material is cleaned and dried to obtain the NiCoFeCuAg-LDH electrode material loaded on nickel foam.

3. The method for preparing the electrode material according to claim 2, characterized in that, The molar ratio of the nickel salt, cobalt salt, iron salt, copper salt, and silver salt is 1:1:1:1:

1.

4. The method for preparing the electrode material according to claim 2, characterized in that, The amount of SDS used is 0.1-0.5 g.

5. The method for preparing the electrode material according to claim 2, characterized in that, The hydrothermal temperature was 160°C, and the time was 12 hours.

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