A high-entropy alloy composite matched with d-p energy level of chalcogen selenium-based positive electrode material, and a preparation method and application thereof

Abstract

This invention provides a high-entropy alloy composite that matches the d-p energy levels of chalcogenide selenium-based cathode materials, wherein the high-entropy alloy in the high-entropy alloy composite is Fe. a Co b Ni c Cu d Cr e Where 0.9≤a≤1.1, 0.9≤b≤1.1, 0.9≤c≤1.1, 0.9≤d≤1.1, and 0.9≤e≤1.1, the chalcogenide selenium-based cathode material is Se. x S y Where x is 0 < x ≤ 8 and y is 0 ≤ y ≤ 8; the d-p energy level difference t between the high-entropy alloy and the chalcogenide selenium-based cathode material is 0.1 ≤ t ≤ 0.5. This invention effectively accelerates the charge transfer process at the conductive agent / cathode / electrolyte interface and significantly improves the cathode reaction kinetics by introducing the high-entropy alloy composite. It provides a universal design strategy for improving the performance of next-generation all-solid-state batteries.

Description

Technical Field

[0001] This invention relates to the field of chalcogenide cathode materials, and in particular to a high-entropy alloy composite that matches the dp energy level of chalcogenide selenium-based cathode materials, its preparation method, and its application. Background Technology

[0002] Rechargeable lithium-sulfur batteries, including lithium-sulfur (Li-S) and lithium-selenium (Li-Se) systems, are considered strong candidates for next-generation energy storage technologies due to their excellent theoretical energy density. Selenium and sulfur-selenium solid solutions (Se...) x S y Li₂X (X=S, Se) has been proposed as a chalcogenide selenium-based cathode material. Sulfur possesses extremely high theoretical specific capacity, while selenium exhibits superior electronic conductivity and faster redox reaction kinetics. However, the performance of these chalcogenide selenium-based cathode materials in practical applications is still severely limited by multiple factors, including slow conversion reaction kinetics, significant volume changes, and the incomplete reversibility of the Li₂X (X=S, Se) conversion reaction, especially prominent in all-solid-state battery systems. In all-solid-state lithium chalcogenide batteries, while the presence of a solid electrolyte effectively suppresses the shuttle effect, it also significantly exacerbates the problem of limited interfacial kinetics. The large interfacial impedance and slow charge transfer behavior caused by the solid-solid interface easily lead to significant polarization, a decrease in electrochemical rate performance, and rapid capacity decay under high-activity material loading conditions.

[0003] Introducing catalysts has proven to be an effective strategy for accelerating redox reactions of chalcogenide species by enhancing interfacial charge transfer and modulating the adsorption behavior of reaction intermediates. However, conventional single-metal catalysts or simple alloys typically have limited active sites and relatively rigid electronic structures, making it difficult to simultaneously adapt to selenium or sulfose-selenium solid solutions (Se... x S y The different chemical environments in which selenium-based chalcogenide cathode materials are used. This inherent limitation has prompted the exploration of catalytic systems with greater versatility and highly tunable electronic structures.

[0004] Therefore, it is necessary to develop a high-entropy alloy that matches the dp energy level of chalcogenide selenium-based cathode materials, so that it can have excellent catalytic performance in all-solid-state lithium-chalcogenide battery applications, improve the conversion kinetics of cathode materials, reduce battery volume expansion, and reduce the interfacial impedance of solid-solid interface contact. This will result in a high-entropy catalyst with low polarization and excellent electrochemical rate performance for use in chalcogenide selenium-based cathode materials, significantly improving the overall electrochemical performance of solid-state batteries. Summary of the Invention

[0005] This invention addresses the problems of slow conversion reaction kinetics in existing chalcogenide selenide-based cathode materials, leading to significant polarization, decreased electrochemical rate performance, and rapid capacity decay in all-solid-state lithium chalcogenide batteries under high-activity material loading conditions. This invention innovatively employs a high-entropy alloy (HEAs) composed of multiple main elements in near-equimolar ratios. Based on the characteristics of chalcogenide selenide-based cathode materials, five specific main elements are selected to form a unique catalytic platform. The high-entropy alloy of this invention exhibits significant lattice distortion, diverse local atomic environments, and strong cooperative electronic effects. Simultaneously, the high-entropy alloy possesses characteristics that match the dp energy level of chalcogenide selenide-based cathode materials. These characteristics endow the high-entropy alloy with abundant active sites, enabling flexible control of the adsorption intensity and reaction pathway of catalytic reactants and intermediates, thereby significantly improving catalytic activity, enhancing the conversion reaction kinetics of the cathode material, and significantly improving the overall electrochemical performance of solid-state batteries.

[0006] This invention is achieved through the following technical solution: In a first aspect, the present invention provides a high-entropy alloy composite that matches the dp energy level of a chalcogenide selenium-based cathode material, wherein the high-entropy alloy is Fe a Co b Ni c Cu d Cr e Where 0.9≤a≤1.1, 0.9≤b≤1.1, 0.9≤c≤1.1, 0.9≤d≤1.1, and 0.9≤e≤1.1, the chalcogenide selenium-based cathode material is Se. x S y Where x is 0 < x ≤ 8 and y is 0 ≤ y ≤ 8; the dp energy level difference t between the high-entropy alloy and the chalcogenide selenium-based cathode material is 0.1 ≤ t ≤ 0.5; Where a, b, c, d, and e represent only the molar percentages of iron, cobalt, nickel, copper, and chromium atoms in the high-entropy alloy, respectively. x S y In this context, x and y represent the molar percentages of selenium and sulfur atoms, respectively.

[0007] When y is 0, the chalcogenide selenium-based cathode material is Se. x .

[0008] The dp energy level difference between the high-entropy alloy and the chalcogenide selenium-based cathode material is the difference between the d-band central energy level of the high-entropy alloy and the p-band central energy level of the chalcogenide selenium-based cathode material.

[0009] This invention provides a high-entropy alloy composite that matches the dp energy level of chalcogenide selenide-based cathode materials. On one hand, the high-entropy alloy has a matched dp energy level with the chalcogenide selenide-based cathode material, which is beneficial for the catalytic conversion of the chalcogenide selenide-based cathode material. On the other hand, the high-entropy alloy has an alloy element composition with matched bond energies. By carefully selecting the types of elements and controlling their atomic molar ratios, complementary and synergistic bond energy distributions are formed between different metal elements within the alloy. The interaction between chromium and other elements will generate significant lattice distortion and stress field, thereby optimizing the electronic structure and surface catalytic activity of the alloy. This bond energy matching forms a gradient and network distribution, thus introducing appropriate internal stress and a tunable electronic environment while maintaining the overall structural stability of the high-entropy alloy.

[0010] Specifically, this invention, based on the energy level matching between the high-entropy alloy and the chalcogenide selenium-based cathode material specified in this invention, facilitates the formation of effective dp coupling at the high-entropy alloy composite-chalcogenide interface. The dp energy level difference between the high-entropy alloy and the chalcogenide selenium-based cathode material is limited to 0.1 ≤ t ≤ 0.5. This facilitates the redistribution of interface charges and promotes the activation and reversible transformation of chalcogenide species. By strictly limiting the energy difference within this range, this invention avoids excessively large energy level differences that would lead to dp energy level mismatch between the high-entropy alloy and the chalcogenide selenium-based cathode, resulting in low orbital hybridization and weak interactions; it also avoids excessively small energy level differences that would cause orbital overlap, excessively strong interactions, and poisoning of catalytic sites. Furthermore, this invention specifies that the high-entropy alloy contains chromium, which has a stable crystal structure. Cr has a small atomic radius, and when it forms high-entropy alloys with Fe, Co, Ni, etc., it produces a synergistic bond energy distribution that can induce significant lattice distortion and stress field, thereby optimizing the electronic structure and surface catalytic activity of the alloy. This chromium-induced localized structural modulation further enhances the adsorption and catalytic conversion capabilities of high-entropy alloy composites for selenium-containing chalcogenide intermediates during charge-discharge processes, effectively improving the utilization rate of active materials. Simultaneously, the introduction of chromium improves the overall mechanical stability and corrosion resistance of the alloy, ensuring the structural integrity of the catalyst during long-cycle processes. Ultimately, this synergistically promotes the efficient, stable, and reversible transformation of chalcogenide selenium-based cathode materials, significantly improving the battery's cycle life and rate performance. Furthermore, the rigidity of Cr and the ductility of Cu complement each other at the atomic scale, jointly maintaining the structural integrity of the high-entropy alloy nanoparticles during repeated charge-discharge volume changes and suppressing the expansion of the cathode system. With the selected elemental composition and atomic molar ratio, this invention successfully constructs a high-performance catalytic system based on energy level matching and multifunctional element synergy. By precisely combining elements such as chromium and copper in a high-entropy alloy with a chalcogenide cathode to form an ideal combination and a good interface with the electrolyte system, it not only greatly promotes the conversion kinetics of chalcogenide species at the electronic level, but also achieves long-term mechanical stability and chemical corrosion protection of the catalyst and active material from a structural perspective. Ultimately, it simultaneously overcomes the problems of slow reaction kinetics, polyselenide shuttle, and electrode structure degradation in lithium chalcogenide batteries, providing a practical material solution for realizing next-generation energy storage devices with high energy density, long cycle life, and excellent rate performance.

[0011] As a further embodiment, the high-entropy alloy in the high-entropy alloy composite is loaded onto a carbon support.

[0012] As a further option, the raw materials for iron, cobalt, nickel, copper, and chromium in the high-entropy alloy are respectively their corresponding metal halide or metal halide hydrate.

[0013] As a further preferred embodiment, the raw materials for iron, cobalt, nickel, copper, and chromium in the high-entropy alloy are their corresponding metal element chloride hydrates.

[0014] As a further preferred embodiment, the ratio of the total number of moles of the metal halide hydrate to the mass of the carbon carrier is (1~1.5) mmol: (180~220) mg.

[0015] This invention further optimizes the source of the aforementioned metal elements by using their corresponding metal chloride hydrates. This ensures high homogeneity at the molecular or ionic scale, further achieving atomic-level homogeneous miscibility in the high-entropy alloy. Simultaneously, chloride ions are easily volatilized and removed during subsequent pyrolysis, avoiding the residue of harmful anions and thus facilitating the acquisition of a pure alloy phase. This raw material selection strategy balances the uniformity of the precursor, the controllability of the synthesis process, and the purity of the final product, providing a solid foundation for the structural consistency and performance reproducibility of the high-entropy alloy composite.

[0016] As an example, the raw materials for the cobalt element include cobalt chloride hexahydrate (CoCl2·6H2O), cobalt chloride dihydrate (CoCl2·2H2O), cobalt bromide hexahydrate (CoBr2·6H2O), etc.

[0017] As an example, the raw materials for the iron element include ferric chloride hexahydrate (FeCl3·6H2O), etc.

[0018] As an example, the raw materials for the nickel element include nickel chloride hexahydrate (NiCl2·6H2O), nickel chloride dihydrate (NiCl2·2H2O), nickel bromide trihydrate (NiBr2·3H2O), nickel iodide hexahydrate (NiI2·6H2O), etc.

[0019] As an example, the raw materials for the copper element include copper fluoride dihydrate (CuF2·2H2O) and copper chloride dihydrate (CuCl2·2H2O).

[0020] As an example, the raw material for the chromium element is selected from chromium chloride tetrahydrate (CrCl2·4H2O), chromium chloride hexahydrate (CrCl3·6H2O), etc.

[0021] As a further example, the carbon support is selected from one or more of carbon nanotubes, Ketjen black, acetylene black, Super P, CMK-3, reduced graphene oxide, VGCF, and modified porous carbon.

[0022] As a further preferred embodiment, the high-entropy alloy is FeCoNiCuCr.

[0023] As a further embodiment, the high-entropy alloy exists on a carbon support in the form of high-entropy alloy nanoparticles.

[0024] As a further embodiment, the particle size range of the high-entropy alloy nanoparticles is 10~100nm.

[0025] As a further embodiment, the dp energy level difference t between the high-entropy alloy and the chalcogenide selenium-based cathode material is 0.3 ≤ t ≤ 0.4.

[0026] As a further option, the sulfide selenium-based cathode Se... x S y x / y≥0.5.

[0027] As a further preferred embodiment, the sulfide selenium-based cathode material is SeS2 or Se.

[0028] As a further embodiment, the high-entropy alloy has a face-centered cubic (FCC) single-phase solid solution structure.

[0029] As a further embodiment, the XRD of the high-entropy alloy has characteristic diffraction peaks corresponding to the (111), (200) and (220) crystal planes.

[0030] As a further embodiment, the lattice pattern of the high-entropy alloy has lattice stripes with spacings of 0.206 nm and 0.170 nm, respectively.

[0031] As a further embodiment, a chalcogenide selenium-based solid-state battery containing the aforementioned high-entropy alloy composite is used at 2C, 1.53 mg / cm³. -2 The active material surface loading remains ≥600 mAh g after 1800 cycles. -1 Reversible capacity.

[0032] As a further embodiment, a chalcogenide selenium-based solid-state battery containing the aforementioned high-entropy alloy composite operates at 1C and 1.53 mg / cm³. -2 The capacity retention rate is ≥95% after 1200 cycles at the active substance surface loading level.

[0033] As a further embodiment, a chalcogenide selenium-based solid-state battery containing the aforementioned high-entropy alloy composite is used at 0.2C and 4.08 mg / cm³. -2 The capacity retention rate after 200 cycles is ≥88% under the surface loading of active material.

[0034] In a second aspect, the present invention provides a method for preparing the high-entropy alloy described in the first aspect, comprising the following steps: S1: Mix the metal halide hydrates of five metals—iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and chromium (Cr)—with a carbon support, and grind them to obtain a composite precursor. S2: The composite precursor obtained in S1 is dried; placed in an inert gas atmosphere, subjected to instantaneous carbon thermal shock treatment by applying voltage, cleaned, and dried to obtain a high-entropy alloy composite.

[0035] This invention innovatively employs a method of applying voltage to induce instantaneous carbothermal shock to obtain high-entropy alloys. This method reduces the damage to structural stability caused by prolonged heating and also shortens the time cost in high-entropy alloy preparation. The high-entropy alloy prepared by applying voltage to induce instantaneous carbothermal shock reduces phase separation and improves product purity, resulting in a pure-phase, high-purity high-entropy alloy composite. Furthermore, this invention specifies that the high-entropy alloy is loaded onto a carbon support. This allows for better uniform dispersion of the high-entropy alloy on the carbon support, preventing the uneven local elemental distribution caused by the aggregation of metal halide hydrates when used alone during instantaneous carbothermal shock. It also avoids problems such as local phase separation, elemental segregation, and abnormal grain coarsening caused by high-temperature sintering. During the instantaneous carbothermal shock, the extremely high heating rate causes multiple metal ions in the precursor to be instantly and synchronously reduced and rapidly alloyed to form a single solid solution phase. This kinetic process greatly suppresses the thermodynamic phase separation tendency caused by differences in diffusion coefficients among the components. Simultaneously, the extremely short ultra-high temperature residence time, combined with a certain amount of carbon support, ensures a uniform and controlled particle size distribution. Therefore, the instantaneous carbon thermal shock method adopted in this invention is an efficient, precise and scalable synthesis strategy that combines the characteristics of raw materials. It fundamentally ensures that the high-entropy alloy composite has an ideal microstructure with uniform composition, simple structure and good dispersion, thus laying a solid material foundation for achieving excellent electrochemical performance in chalcogenide selenium-based batteries.

[0036] As a further option, the grinding time is 20-40 minutes.

[0037] As a further option, the drying temperature is 50~70℃.

[0038] As a further embodiment, the voltage of the carbon thermal shock treatment is 80~120 V, and the duration is 0.3~0.5 seconds.

[0039] As a further step, the cleaning process involves using ethanol to remove residual salts and impurities.

[0040] As a further preferred embodiment, the method for preparing the high-entropy alloy includes the following steps: S1: Metal chloride hydrates of iron (Fe), cobalt (Co), nickel (Ni), copper (Cu) and chromium (Cr) are mixed in the target stoichiometric ratio, thoroughly mixed with a carbon support, and ground for 30 min to obtain the composite precursor; S2: The composite precursor obtained in S1 was dried at 60°C; the dried mixture was then uniformly spread between two sheets of carbon cloth and subjected to carbothermal shock treatment under an argon atmosphere. A voltage of 100V was applied for 0.4s during this process. After the thermal shock treatment, the resulting product was thoroughly washed with ethanol and dried to obtain the high-entropy alloy composite.

[0041] Thirdly, the present invention also provides an application of the high-entropy alloy in a battery, the battery comprising a high-entropy alloy composite.

[0042] The features and beneficial effects of this invention are as follows: 1. This invention employs five specific elements—Fe, Co, Ni, Cu, and Cr—in a near equimolar ratio to construct a high-entropy alloy. This combination achieves synergistic optimization of electronic structure, mechanical properties, and chemical stability. For the first time, the energy level difference between the d-band center of the high-entropy alloy and the p-band center of the chalcogenide selenium-based cathode material is explicitly limited to the range of 0.1 to 0.5. This precise energy level matching aims to promote effective dp orbital coupling at the interface, optimize charge transfer, regulate the catalytic process at the electronic level, lower the energy barrier of redox reactions of chalcogenide species, accelerate the kinetics of multi-step conversion reactions, effectively reduce battery polarization, and thus significantly improve the rate performance of the battery. This invention specifically introduces chromium (Cr), whose "rigid" structural characteristics complement the "ductility" and high conductivity of copper (Cu), jointly enhancing the alloy's structural stability, corrosion resistance, and interfacial charge transport capability.

[0043] 2. This invention employs a transient carbothermal shock method to synthesize high-entropy alloys. By applying a short-duration high voltage to a mixture of a metal halide precursor and a carbon support in a specific ratio under an inert atmosphere, rapid and uniform alloying is achieved. This method offers advantages such as speed, energy efficiency, and suppression of elemental segregation. It can yield high-entropy alloy nanoparticles with uniform elemental distribution, controllable particle size, and a pure phase, all loaded onto a carbon support. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 The XRD patterns are those of the high-entropy alloy composites prepared in Example 1, Comparative Example 1, and Comparative Example 2.

[0046] Figure 2 The image shows a transmission electron microscope (TEM) image of the high-entropy alloy composite prepared in Example 1.

[0047] Figure 3 This is a high-resolution transmission electron microscope image of the high-entropy alloy composite prepared in Example 1.

[0048] Figure 4 This is a magnified high-resolution transmission electron microscope image of the high-entropy alloy composite prepared in Example 1.

[0049] Figure 5 The images shown are scanning transmission electron microscopy (STEM) images and elemental energy dispersive spectroscopy (EDS) images of the high-entropy alloy composite prepared in Example 1.

[0050] Figure 5 Image a in Example 1 is a scanning transmission electron microscope image of the high-entropy alloy composite prepared in Example 1. Figure 5 Image b is the energy spectrum image of iron in the high-entropy alloy composite prepared in Example 1; Figure 5 c is the cobalt element energy spectrum image of the high-entropy alloy composite prepared in Example 1; Figure 5 In the image, d represents the energy spectrum of nickel in the high-entropy alloy composite prepared in Example 1. Figure 5 In Figure e, the copper element energy spectrum image of the high-entropy alloy composite prepared in Example 1 is shown. Figure 5 f is the chromium energy spectrum image of the high-entropy alloy composite prepared in Example 1.

[0051] Figure 6 Examples 1, 2, 3, 4, 5, and 6 were tested at a current of 1.53 mg / cm² at 1C. -2 Constant current charge-discharge curves under active materials.

[0052] Figure 7 The graph shows a comparison of the polarization voltages corresponding to the constant current charge-discharge curves of Examples 1, 2, 3, 4, 5, and 6.

[0053] Figure 8 The cyclic voltammetry curves for Example 1 at 0.1 mV / s at 30°C, 40°C, 50°C, and 60°C are shown.

[0054] Figure 9 The relaxation time distribution curves of Example 1 and Comparative Example 3 during the charging phase are shown.

[0055] Figure 10 The graph shows the evolution of the positive electrode relaxation time distribution function γ(τ) during the discharge process of Examples 1, 2, 3, 4, 5, and 6.

[0056] Figure 11 The cyclic voltammetry curves for Examples 1, 2, and 5 at 30°C are shown.

[0057] Figure 12 Tafel curves of oxidation peaks for Examples 1, 2, 3, 4, 5, and 6.

[0058] Figure 13 The TDOS of the d-band of the high-entropy alloy composite is compared with the TDOS of the p-band of Se, SeS2 and S.

[0059] Figure 14 This represents the adsorption energy of the high-entropy alloy composite for different species.

[0060] Figure 15 The TDOS of the d-band of the high-entropy alloy composites in Examples 1, 2, and 5 with the p-band of Se, the p-band of SeS2, and the p-band of S, respectively.

[0061] Figure 15 In Example 1, 'a' represents the TDOS of the d-band and p-band of Se at the high-entropy alloy composite-Se interface. Figure 15 In Example 2, b represents the TDOS of the d-band and p-band of the high-entropy alloy composite-SeS2 interface. Figure 15 In the figure, c represents the TDOS of the d-band and p-band of the high-entropy alloy composite-S interface in Comparative Example 5.

[0062] Figure 16 The differential charge density is for Example 1, Example 2, and Comparative Example 5.

[0063] Figure 16 In Figure 'a', the differential charge density diagram is from Example 1. Figure 16 In Figure b, the differential charge density diagram is from Example 2. Figure 16 In the middle, c is the differential charge density diagram of Comparative Example 5.

[0064] Figure 17 Examples 1, 2, and 3 were prepared at 1°C with a concentration of 1.53 mg / cm³. -2 Cyclic performance under current.

[0065] Figure 18 Example 1 and Comparative Example 7 were tested at 1°C, 1.53 mg / cm³. -2 Long-cycle performance.

[0066] Figure 19 Examples 1, 2, and 5 were prepared at 1°C with 1.53 mg / cm³.-2 Long-cycle performance.

[0067] Figure 20 Example 1 and Comparative Example 3 were tested at 1°C, 1.53 mg / cm³. -2 Long-cycle performance.

[0068] Figure 21 The charging and discharging curves for Example 1 at different numbers of cycles are shown.

[0069] Figure 22 Example 1 and Comparative Example 3 were prepared at 2C, 1.53 mg cm -3 Long-cycle performance.

[0070] Figure 23 Example 1 and Comparative Example 3 were prepared at 0.2°C and 4.08 mg / cm³. -2 Cyclic performance under high load.

[0071] Figure 24 The image shows the non-in-situ Se 3d XPS spectrum of Comparative Example 3 during the cycling process.

[0072] Figure 25 The image shows the non-in-situ Se 3d XPS spectrum of Example 1 during the cyclic process.

[0073] Figure 26 The image shows the in-situ Raman spectrum of Comparative Example 3 during the first cycle.

[0074] Figure 27 This is the in-situ Raman spectrum of Example 1 during the first cycle.

[0075] Figure 28 The TDOS of the d-band is for Example 1 and Comparative Examples 1 and 2.

[0076] Figure 29 The image shows the XRD pattern of the high-entropy alloy composite prepared in Comparative Example 8.

[0077] Figure 30 The images shown are scanning transmission electron microscopy (STEM) images and elemental energy dispersive spectroscopy (EDS) images of the high-entropy alloy composite prepared in Comparative Example 8.

[0078] Figure 30 Image a in Figure 8 is a scanning transmission electron microscope image of the high-entropy alloy prepared in Comparative Example 8. Figure 30 Image b is the energy spectrum of iron in the high-entropy alloy prepared in Comparative Example 8; Figure 30 In the middle c, the cobalt element energy spectrum image of the high-entropy alloy prepared in Comparative Example 8 is shown. Figure 30 In the image, d is the energy spectrum of nickel in the high-entropy alloy prepared in Comparative Example 8; Figure 30 In Figure e, the energy spectrum of copper in the high-entropy alloy prepared in Comparative Example 8 is shown. Figure 30 f is the energy spectrum image of chromium in the high-entropy alloy prepared in Comparative Example 8. Detailed Implementation

[0079] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below, and embodiments of the present invention will be provided, but this does not limit the scope of the present invention.

[0080] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0081] The chemical raw materials used in the following examples and comparative examples are all prior art and commercially available. The experimental apparatus and testing equipment used in the following examples and comparative examples are all conventional equipment in the art, and there are no special requirements or limitations.

[0082] As a specific example of the implementation of this invention, detailed cases are provided below: Example 1: Synthesis of High Entropy Alloy Composite (HEA): Hydrated metal chlorides of Fe, Co, Ni, Cu, and Cr were selected as metal precursors. Each precursor salt (FeCl3·6H2O, CoCl2·6H2O, NiCl2·6H2O, CuCl2·2H2O, CrCl3·6H2O) was mixed thoroughly with 200 mg of carbon carrier Ketjen Black (KB) at a concentration of 0.25 mmol each, and manually ground for 30 min. The resulting composite precursor was then dried at 60 °C. Next, 20 mg of the dried mixture was evenly spread between two sheets of carbon cloth and subjected to carbon thermal shock treatment under an argon atmosphere. A voltage of 100 V was applied for 0.4 s during this process. After the thermal shock treatment, the product was thoroughly washed with ethanol to remove residual salts and impurities, and then dried to obtain the high entropy alloy composite. Preparation of the positive electrode: Selenium (Se), lithium phosphorus sulfide chlorine (LPSCl), Ketjen black (KB) and high entropy alloy composite were mixed in a mass ratio of 40:40:20:2 and ball-milled at 550 rpm for 7.2 h under an argon atmosphere to obtain positive electrode powder, thus obtaining the Se-HEA positive electrode; Battery Assembly: The all-solid-state Li-Se battery was assembled in an argon-filled glove box using a 10mm diameter mold battery. First, 90mg of LPSCl powder was pressed at 240MPa for 3 minutes to form a dense electrolyte sheet. Then, positive electrode powder was uniformly spread on one side of the LPSCl electrolyte sheet and pressed at 360MPa for 3 minutes. Next, a Li-In alloy negative electrode was placed on the other side of the electrolyte sheet and pressed at 120MPa for 3 minutes. Finally, a stacking pressure of 60MPa was applied to the battery using three bolts, and electrochemical testing was performed after a 12-hour rest period.

[0083] Example 2: Unlike Example 1, in the preparation of the positive electrode, selenium was replaced with SeS2 to obtain the SeS2-HEA positive electrode.

[0084] Example 3: Unlike Example 1, each precursor salt with a different molar ratio was thoroughly mixed with the carbon support Ketjen black (KB) in the ratio of 0.238 mmol FeCl3·6H2O: 0.25 mmol CoCl2·6H2O: 0.262 mmol NiCl2·6H2O: 0.275 mmol CuCl2·2H2O: 0.225 mmol CrCl3·6H2O, and then manually ground for 30 min.

[0085] Example 4: Unlike Example 1, hydrated metal chlorides of Fe, Co, Ni, Cu, and Cr were selected as metal precursors. Each precursor salt (FeCl3·6H2O, CoCl2·6H2O, NiCl2·6H2O, CuCl2·2H2O, and CrCl3·6H2O) was thoroughly mixed with 200 mg of carbon carrier Ketjen black (KB) at a concentration of 0.20 mmol each, and then manually ground for 30 min.

[0086] Comparative Example 1: Unlike Example 1, a ternary FeCoNi alloy composite was used instead of the high-entropy alloy composite; Specifically, each precursor salt, FeCl3·6H2O, CoCl2·6H2O, and NiCl2·6H2O, was thoroughly mixed with 200 mg of carbon carrier Ketjen black (KB) at a concentration of 0.417 mmol and then manually ground for 30 min.

[0087] Comparative Example 2: Unlike Example 1, the high-entropy alloy composite was replaced with a separate Co composite; Specifically, the precursor salt CoCl2·6H2O was thoroughly mixed with 200 mg of carbon carrier Ketjen black (KB) at a ratio of 1.25 mmol and then manually ground for 30 min.

[0088] Comparative Example 3: Unlike Example 1, no high-entropy alloy composite was added during the preparation of the cathode; a Se-Blank cathode was obtained. Specifically, commercial selenium (Se), lithium phosphorus sulfur chloride (LPSCl), and Ketjen black (KB) were mixed in a mass ratio of 40:40:20 and ball-milled at 550 rpm for 7.2 h under an argon atmosphere.

[0089] Comparative Example 4: Unlike Example 2, no high-entropy alloy composite was added during the preparation of the cathode, resulting in a SeS2-Blank cathode; Specifically, SeS2, lithium phosphorus sulfur chloride (LPSCl), and Ketjen black (KB) were mixed in a mass ratio of 40:40:20 and ball-milled at 550 rpm for 7.2 h under an argon atmosphere.

[0090] Comparative Example 5: Unlike Example 1, Se in the preparation of the positive electrode was replaced with S8; thus, an S-HEA positive electrode was obtained. Specifically, BP2000 and S8 were first mixed at a mass ratio of 20:80 and heated at 155°C for 12 hours under an argon atmosphere to obtain the BP2000 / S composite. Subsequently, BP2000 / S, LPSCl, KB, and the high-entropy alloy composite were ball-milled at 550 rpm for 7.2 hours under an argon atmosphere to prepare the cathode material.

[0091] Comparative Example 6: Unlike Comparative Example 5, no high-entropy alloy composite was added during the preparation of the cathode; thus, an S-Blank cathode was obtained. Specifically, BP2000 and S8 were mixed at a mass ratio of 20:80 and heated at 155°C for 12 hours under an argon atmosphere to obtain the BP2000 / S composite. Subsequently, BP2000 / S, LPSCl, and KB were ball-milled at 550 rpm for 7.2 hours under an argon atmosphere to prepare the cathode material.

[0092] Comparative Example 7: Unlike Example 1, the high-entropy alloy FeCoNiCuCr was replaced with FeCoNiCuMo; Specifically, the high-entropy alloy composite was synthesized using FeCl3·6H2O, CoCl2·6H2O, NiCl2·6H2O, CuCl2·2H2O, and Na2MoO4·2H2O as metal precursors. Each precursor salt was thoroughly mixed at a concentration of 0.25 mmol with 200 mg of Ketjen Black (KB) and manually ground for 30 min.

[0093] Comparative Example 8: Unlike Example 1, the high-entropy alloy composite synthesized by thermal shock treatment was replaced by the high-entropy alloy composite synthesized by conventional annealing. Specifically, 0.5 mmol of FeCl3·6H2O, CoCl2·6H2O, NiCl2·6H2O, CuCl2·2H2O, and CrCl3·6H2O were added to 40 mL of ultrapure water to form a homogeneous mixed solution. This mixture was then placed in an 80°C oil bath and stirred continuously until all the water evaporated, yielding a deep yellow slurry. The slurry was then annealed in a tube furnace at 500°C for 2 hours under a 5% H2 / Ar atmosphere.

[0094] The following tests were performed on Examples 1-4 and Comparative Examples 1-8: (1) 1C, 1.53mg cm -2 Under surface load conditions, it can undergo 1200 constant current charge-discharge cycles. (2) 2C, 1.53mg cm -2 Under surface load conditions, it can withstand 1800 constant current charge-discharge cycles. (3) Under 0.2C conditions, at a relatively high active substance loading (4.08 mg cm⁻¹) -2 Cyclic under the following conditions; (4) Cyclic voltammetry test under 0.1mV / s condition, in-situ AC impedance spectrum test and corresponding relaxation time distribution analysis, Tafel slope test; (5) Calculation of adsorption energy of high-entropy alloy for different species, calculation of the d-band center energy level of the alloy and the p-band center energy level of various positive electrodes. The calculation method is based on the reference ACS Nano 2025, 19, 9182-9195 High Rate and Long-Cycle Life of Lithium-Sulfur Battery Enabled by High d-Band Center of High-Entropy Alloys DOI: 10.1021 / acsnano.4c18642.

[0095] The data obtained from the above tests in Examples 1-3 and Comparative Examples 1-8 are shown in Table 1 below: Table 1

[0096] Depend on Figure 1As can be seen, the XRD results of the high-entropy alloy composite (HEA) prepared in Example 1 confirm the successful construction of a face-centered cubic (FCC) high-entropy alloy in the material, with its characteristic diffraction peaks corresponding to the (111), (200), and (220) crystal planes. Compared with pure Co in Comparative Example 2, the diffraction peaks of FeCoNi in Comparative Example 1 and the HEA sample in Example 1 are slightly shifted towards a lower 2θ angle. This is attributed to the introduction of multiple metal elements with different atomic radii into the Co lattice, resulting in overall lattice expansion. This phenomenon conforms to Vegard's law and the lattice distortion effect of high-entropy alloys. Notably, no additional diffraction peaks or peak splitting phenomena related to impurity phases were observed, indicating that a single-phase solid solution structure was formed, rather than a simple physical mixture.

[0097] Depend on Figure 2 As can be seen, the structural details of the high entropy alloy composite (HEA) prepared in Example 1 were revealed by TEM, in which the contrast difference between the carbon support and the dispersed high entropy alloy nanoparticles can be clearly observed: the gray area corresponds to the Ketjen black (KB) carbon support, while the dark particles uniformly distributed on the surface of the Ketjen black (KB) carbon support belong to the high entropy alloy nanoparticles, with a maximum size of about 100 nm.

[0098] Depend on Figure 3 and Figure 4 It can be seen that the high-entropy alloy nanoparticles prepared in Example 1 have clearly distinguishable lattice fringes, indicating that they have high crystallinity. Figure 3 The magnified lattice image of the region is as follows Figure 4 The lattice fringes with spacings of 0.206 nm and 0.170 nm are shown, belonging to the (111) and (200) crystal planes of the face-centered cubic (FCC) structure, respectively.

[0099] Depend on Figure 5 As can be seen, the elemental mapping analysis results show that Fe, Co, Ni, Cu and Cr elements exhibit a uniform spatial distribution in the high-entropy alloy nanoparticles prepared in Example 1, indicating that high-entropy alloy nanoparticles with uniform composition and no obvious elemental segregation were successfully constructed.

[0100] Figure 6 The constant current charge-discharge curves of the cathodes in Examples 1, 2, and Comparative Examples 3-6 were compared. With the introduction of HEA, the discharge capacity of all three cathode systems was significantly improved. Specifically, the Se cathode, SeS2 cathode, and S cathode containing the high-entropy alloy composite (HEA) exhibited discharge capacities of 764, 867, and 673 mAh g, respectively. -1 The discharge capacity is significantly higher than that of the corresponding blank Se cathode, SeS2 cathode, and S cathode (681, 740, and 387 mAh g), respectively. -1Furthermore, it can be seen that the discharge capacity of the Se cathode and SeS2 cathode containing the high entropy alloy composite (HEA) catalyst is significantly higher than that of the S cathode containing the high entropy alloy composite (HEA) catalyst.

[0101] Furthermore, the constant current charge-discharge curves show that, in all three cathode systems, the HEA-based electrode (Examples 1, 2, and Comparative Example 5) exhibits a higher discharge plateau and a lower charge plateau. Compared to the blank control electrode (Comparative Example 3, 4, and 6), its voltage hysteresis is significantly reduced, which is clearly reflected by the decrease in the voltage difference between the charge and discharge plateaus. The reduction in polarization indicates that the reaction kinetics are enhanced during the electrochemical conversion process, and the reaction energy barrier is effectively lowered. This effect is particularly evident in the Se cathode system and the SeS2 cathode system, highlighting the effect of HEA on Se… x S y The positive electrode provides a stronger kinetic boost.

[0102] Depend on Figure 7 It can be seen that the polarization voltage extracted from the charge-discharge curve is summarized as follows: Figure 7 The results showed that the polarization voltages of HEA-based Se and HEA-based SeS2 in Examples 1 and 2 decreased from 420mV and 503mV in Comparative Examples 3 and 4 to 350mV and 436mV, respectively. The polarization voltage of HEA-based S in Comparative Example 5 decreased only from 645mV in Comparative Example 6 to 619mV.

[0103] Therefore, from the above Figure 6 and Figure 7 It can be seen that the simultaneous increase in positive electrode discharge capacity and the effective suppression of polarization jointly indicate that HEA can significantly accelerate the discharge of Se in the chalcogenide selenium-based positive electrode system in the all-solid-state system. x S y The redox reaction kinetics.

[0104] Depend on Figure 8 It can be seen that the effect of the HEA prepared in Example 1 on the apparent activation energy (Ea) of the positive electrode redox reaction was studied using cyclic voltammetry (CV). With increasing temperature, the peak current gradually increases, indicating that the electrochemical reaction process is thermally activated. Simultaneously, the potential difference between the oxidation and reduction peaks continuously decreases, indicating a reduction in polarization and enhanced electrochemical reversibility.

[0105] Depend on Figure 9 The evolution behavior of impedance at different time scales was further revealed through relaxation time distribution (DRT) analysis. Figure 9The DRT spectrum of the Se-HEA cathode from Example 1 during charging is shown. The relaxation peaks within the 1–10 s time constant range are typically associated with the interfacial charge transfer resistance at the cathode-electrolyte interface. As charging progresses, the intensity of these relaxation peaks gradually increases, indicating that the contribution of the charge transfer process to the overall impedance is continuously increasing. In contrast, during discharging, the intensity of the same relaxation peak exhibits the opposite trend. Notably, at all corresponding potentials, the relaxation peak intensity of the blank Se cathode from Comparative Example 3 is consistently higher than that of the HEA-based cathode, indicating that it has a larger charge transfer resistance. This result demonstrates that the introduction of HEA can effectively promote the interfacial charge transfer process, thereby improving the reaction kinetics of the Se cathode.

[0106] Depend on Figure 10 As can be seen, to achieve quantitative comparison, the relaxation peak intensities related to charge transfer at different potentials during the charging and discharging process were extracted and summarized. The results clearly show that HEA reduces Se to varying degrees. x S y Charge transfer resistance of the positive electrode system.

[0107] Depend on Figure 11 As can be seen, the redox kinetics of the three cathode systems were further evaluated by cyclic voltammetry (CV) analysis. Compared with the corresponding blank cathode, the potential interval between the oxidation and reduction peaks of the HEA-based Se and HEA-based SeS2 cathodes in Examples 1 and 2 was significantly reduced, indicating that polarization was effectively suppressed and redox kinetics were significantly enhanced. In contrast, the potential difference between the reduction and oxidation peaks of the S cathode in Comparative Example 5 only changed slightly after the introduction of HEA. This result is consistent with the polarization voltage analysis results obtained from the constant current charge-discharge curves.

[0108] To further quantitatively characterize the kinetic enhancement effect, the Tafel slope during the charging process was extracted from the CV curve and summarized in... Figure 12 The Tafel slopes of the HEA-based Se, SeS2, and S cathodes are 296, 340, and 393 mV dec, respectively. -1 The dec values ​​were significantly lower than the corresponding blank cathode values ​​of 327, 381, and 457 mV. -1 The decrease in the Tafel slope indicates that the charge transfer process is more facilitated, which further confirms the role of HEA in promoting Se. x S y Effective catalytic effect in positive electrode redox reaction.

[0109] To gain a deeper understanding of the catalytic effects of different chalcogenide cathodes in Example 1, by Figure 13As can be seen, the electronic structure of HEA, Se, SeS2, and S cathode materials was compared through theoretically calculated density of states (DOS) analysis, as described in ACS Nano 2025, 19, 9182-9195, "High Rate and Long-Cycle Life of Lithium-Sulfur Battery Enabled by High d-Band Center of High-Entropy Alloys" (DOI: 10.1021 / acsnano.4c18642). The d-band center of HEA is located at -0.996 eV, while the p-band centers of Se, SeS2, and S are located at -1.358, -1.385, and -1.818 eV, respectively. At this point, the dp energy level differences between the high-entropy alloy and the cathode material are 0.362, 0.389, and 0.822 eV, respectively. At this point, the p-band centers of Se and SeS2 are energy-closer to the d-band centers of HEA, exhibiting a more favorable energy level matching relationship compared to S. This indicates that effective dp coupling is more readily formed at the high-entropy alloy-chalcogenide selenium-based element interface. In addition to the energy band center matching, HEA also exhibits a significantly broadened d-band characteristic, with continuously distributed electronic states near the Fermi level, thus forming a wider energy overlap window with the p-states of Se and SeS2. This enhanced dp hybridization facilitates the redistribution of interface charge and promotes the activation and reversible transformation of chalcogenide species. In contrast, the more negative p-band center of sulfur in Comparative Example 5 indicates a relatively weaker electronic coupling with the near-Fermi level d-states of HEA, which to some extent explains the relatively limited improvement in kinetics observed in the S cathode system.

[0110] The adsorption energy was calculated using the reference ACS Nano 2025, 19, 9182-9195, "High Rate and Long-Cycle Life of Lithium-Sulfur Battery Enabled by High d-Band Center of High-Entropy Alloys" (DOI: 10.1021 / acsnano.4c18642). Figure 14This paper presents the calculated adsorption energies of HEA for different chalcogenide selenium-based cathode materials, their representative intermediates, and final discharge products, revealing its stage-dependent and component-dependent catalytic behavior. From the perspective of reaction stages, HEA exhibits weak interactions with the original cathode active material in the charged state, moderate interactions with the final discharge products, and the strongest interactions with reaction intermediates. Specifically, the adsorption energies of intermediate species (Li₂Se₂ and Li₂S₂) are significantly higher than those of their corresponding chalcogenide selenium-based cathode materials and final products, indicating that HEA preferentially stabilizes key reaction intermediates during electrochemical conversion. From the perspective of chalcogenide chemical composition, there are significant differences between selenium-based and sulfur-based species. In all reaction stages, the adsorption energies of selenium-containing species on the HEA surface are generally better than those of their corresponding sulfur-containing species, indicating stronger interfacial interactions between them and the HEA surface, with weaker interactions between elemental sulfur and HEA. Similarly, the adsorption strength of intermediate Li₂Se₂ is significantly higher than that of Li₂S₂, while the final discharge products Li₂Se and Li₂S exhibit similar adsorption strengths.

[0111] By analyzing the energy level difference between the d-band center of HEA and the p-band center of chalcogenide selenium-based cathode materials after interaction with HEA, the interfacial electronic coupling strength was further evaluated. Figure 15 As shown, among the three systems, the HEA-Se interface in Example 1 and the HEA-SeS2 interface in Example 2 both exhibit smaller d–p energy level differences, while the HEA-S system in Comparative Example 5 shows the largest energy level separation. A smaller dp energy level difference implies stronger orbital overlap and more efficient interfacial electronic coupling, thus facilitating rapid charge transfer during electrochemical reactions; conversely, the larger energy level separation in the sulfur system indicates weaker orbital hybridization with the HEA.

[0112] like Figure 16 The charge density difference contour lines shown indicate that during the adsorption of elemental chalcogenide species, charge redistribution is mainly confined to the interior of the adsorbed molecules, with only limited interfacial charge transfer occurring between the HEA surface and the reactants. In contrast, significant charge redistribution is clearly observed at the HEA-product interface for reaction intermediates and the final product, indicating a stronger electronic interaction between the HEA and these species. These stage-dependent electronic interaction characteristics suggest that the interaction between the HEA and reaction intermediates and the final product is stronger than its interaction with the initial reactants. This characteristic is beneficial for maintaining good reaction reversibility while lowering the reaction kinetic energy barrier, consistent with the Sabatier principle. Furthermore, compared to sulfide species, selenium-containing species induce a more significant charge redistribution on the HEA surface, further indicating a stronger electronic coupling between the HEA and selenium-containing species.

[0113] because Figure 17 As can be seen from the comparison between Example 1 and Comparative Examples 1-3, the all-solid-state lithium-chalcogen battery with dp energy level matching regulated by the high-entropy alloy catalysis of the present invention exhibits higher cycle performance compared with the use of no high-entropy alloy catalysis, or the use of single metal catalysts or simple alloys for catalysis. This is due to the fact that the high-entropy alloy composite-chalcogen element interface defined by the present invention is more likely to form effective dp coupling, which is conducive to the redistribution of interface charge and promotes the activation and reversible process of chalcogen species.

[0114] Depend on Figure 18 As can be seen, comparing the cycle performance of Se cathodes in Example 1 and Comparative Example 7 using high-entropy alloys with different elemental compositions, Example 1 specifies that the high-entropy alloy contains chromium, which has a stable crystal structure. Cr has a small atomic radius and, when forming high-entropy alloys with Fe, Co, Ni, etc., can produce significant lattice distortion and stress fields, thereby optimizing the electronic structure and surface catalytic activity of the alloy. This chromium-induced localized structural modulation can further enhance the adsorption and catalytic conversion ability of the high-entropy alloy composite for chalcogenide intermediates containing Se during charge and discharge, effectively improving the utilization rate of active materials. Simultaneously, the introduction of chromium improves the overall mechanical stability and corrosion resistance of the alloy, ensuring the structural integrity of the catalyst during long-term cycling, ultimately synergistically promoting the high efficiency, stability, and reversibility of the chalcogenide selenium-based cathode material, significantly improving the cycle life and rate performance of the battery. Furthermore, the "rigidity" of Cr and the "ductility" of Cu complement each other at the atomic scale, jointly maintaining the structural integrity of the high-entropy alloy nanoparticles during repeated charge and discharge volume changes, suppressing the expansion of the cathode system. This significantly improves the cycle life and rate performance of the battery. In Comparative Example 7, after replacing Cr with Mo in the high-entropy alloy, the energy difference between it and the dp orbital of the sulfoselenium-based cathode is 0.471 eV, which exceeds the optimal range. The excessive energy difference causes the high-entropy alloy and the dp orbital of the sulfoselenium-based cathode to be mismatched, resulting in low orbital hybridization and weak interaction. Therefore, the improvement on the dynamics of the all-solid-state battery is relatively limited, and the discharge capacity and capacity retention are both lower than those in Example 1.

[0115] Figure 19 The long-cycle performance of the high-entropy alloy catalyst introduced under 1C conditions was summarized, and the catalytic universality of HEA in the all-solid-state system and its adaptability to different cathode compositions were systematically demonstrated. Examples 1 and 2 exhibited stable reversible capacity during long-term cycling, indicating that HEA has good catalytic effects in both Se and SeS2 chalcogenide systems.

[0116] Depend on Figure 20As can be seen, the HEA-based Se cathode of Example 1 exhibits the best long-term cycling stability, with almost no capacity decay during more than 1200 cycles; in contrast, Comparative Example 3 shows obvious rapid capacity decay under the same conditions.

[0117] Depend on Figure 21 As can be seen, the constant current charge-discharge curves of the HEA-based Se cathode in Example 1 under different cycle numbers show that, as cycling progresses, its charge-discharge plateau remains consistently good, exhibiting only slight changes in specific capacity and minimal increase in polarization, indicating that the system possesses highly stable reaction kinetics and interfacial properties. Even after long-term cycling, the voltage difference between the charge-discharge plateaus changes only slightly, reflecting that kinetic degradation is effectively suppressed.

[0118] Depend on Figure 22 It can be seen that, under higher 2C conditions, Example 1 still maintains 657 mAh g after 1800 cycles. -1 The reversible capacity of the empty battery is high, while the capacity of the blank battery is significantly and rapidly decayed.

[0119] To further evaluate its performance under practical application conditions, at a higher selenium surface loading (4.08 mg / cm³), -2 The battery's cycle stability was tested. Figure 23 It can be seen that the HEA-based battery prepared in Example 1 still maintains a capacity of 614 mAh g after 200 cycles at 0.2C. -1 The reversible capacity of the first sample showed a capacity retention of approximately 91%; in contrast, the capacity of the second sample (Comparative Example 3) significantly decreased, dropping to 505 mAh g. -1 .

[0120] Therefore, the above results fully demonstrate that introducing high-entropy alloy composites into all-solid-state lithium selenide batteries can significantly improve Se2O3 performance. x S y The cathode reaction kinetics, rate performance, and cycle stability of sulfide selenium-based cathode materials are improved, and their adaptability to conditions with high active material loading and high active material content is significantly enhanced.

[0121] To elucidate the effect of HEA on reaction kinetics and the evolution of selenium species, quasi-in-situ XPS measurements were performed on the electrode under different electrochemical conditions. For example... Figure 24 and Figure 25 As shown, under open-circuit voltage (OCV) conditions, both the blank electrode of Comparative Example 3 and the HEA-based electrode of Example 1 exhibit a dominant Se content at 55-56 eV. 0 The characteristic peaks indicate that the initial state of selenium in the two electrodes is basically the same. When discharged to 0.6V, it corresponds to the intermediate Li₂Se. xNew components of the species and the final discharge product Li₂Se began to appear. Notably, compared to Comparative Example 3, the contribution of Li₂Se in Example 1 was significantly enhanced, while Li₂Se… x The significantly weakened intermediate signal indicates that the introduction of HEA accelerates the conversion of lithium polyselenide to Li₂Se. This result demonstrates that the reaction kinetics are effectively enhanced during discharge, while selenium utilization is more efficient. Se₂Se was observed in both cathodes after recharging to 2.4V. 0 The characteristic signals were largely recovered. However, compared to Comparative Example 3, the HEA-based cathode exhibited significantly fewer residual polyselenide species at 2.4V, indicating that its discharge products could be more completely reconstituted into elemental selenium. These results fully demonstrate the crucial role of HEA in regulating the selenium redox reaction process and enhancing reaction reversibility.

[0122] To further understand the influence of HEA on reaction kinetics and phase evolution behavior during the Li–Se conversion, quasi-in-situ Raman spectroscopy was used to monitor the phase evolution of selenium species during discharge, such as... Figure 26 and Figure 27 As shown, selenium in the cathode mainly exists in an amorphous chain structure, with its characteristic Raman peak located at 254 cm⁻¹. -1 As the discharge voltage decreases, this characteristic peak gradually weakens, indicating that elemental Se... 0 It is gradually transforming into a selenium-lithiated species. Notably, for Example 1, when discharged to 1.3V, it reacts with Se... 0 The associated Raman characteristic peaks almost completely disappeared; however, at the same potential, obvious selenium characteristic peaks were still observed in Comparative Example 3. This significant difference indicates that the introduction of HEA can significantly accelerate the solid-state transformation kinetics of selenium during discharge. 0 The premature disappearance of the signal implies a faster reduction reaction rate and more efficient utilization of active substances, which can be attributed to the enhanced interfacial charge transfer induced by HEA and the optimized adsorption behavior of selenium species.

[0123] Depend on Figure 28As can be seen from Table 1, although the energy difference between the d-band center level and the p-band center level of the chalcogenide selenium-based cathode material in Comparative Examples 1 and 2 is lower than that in Example 1, an excessively small energy difference may cause excessive overlap of the orbitals, resulting in an overly strong effect and poisoning of the catalytic sites. In contrast, HEA also exhibits a significantly broadened and smooth d-band characteristic, with continuously distributed electronic states near the Fermi level, which is beneficial for the redistribution of interface charges and promotes the activation and reversible process of the chalcogenide selenium-based cathode. Meanwhile, because the comparative examples lack chromium and copper in their elemental composition, the catalyst has limited active sites and a relatively rigid electronic structure, making it difficult to adapt to the different chemical environments corresponding to selenium or sulfoselenium solid solutions as chalcogenide selenium-based cathode materials. Furthermore, the lack of chromium contributes to the overall mechanical stability and corrosion resistance of the structure, as well as the stabilization of the crystal structure, resulting in poor electrochemical performance of the prepared battery.

[0124] Depend on Figure 1 and Figure 29 The comparison shows that the XRD pattern of the high-entropy alloy composite prepared by tubular furnace heating in Comparative Example 8 contains impurity peaks. This indicates that the preparation method in Comparative Example 8 requires a long high-temperature treatment time, which is not conducive to the formation of a pure phase. Figure 5 and Figure 30 The comparison shows that the STEM image of HEA prepared by tube furnace heating and the corresponding energy dispersive spectroscopy images of Fe, Co, Ni, Cu, and Cr show uneven elemental distribution, indicating segregation, which is detrimental to stable catalytic performance. However, Example 1 of this invention, which combines a high-entropy alloy composite obtained by carbothermal shock, shortens the time required for heating to avoid damage to structural stability. Furthermore, the high-entropy alloy, as defined in this invention, is loaded onto a carbon support. This allows for better uniform dispersion of the high-entropy alloy on the carbon support, preventing the localized uneven elemental distribution caused by aggregation during instantaneous carbothermal shock, as is common with metal halide hydrates. This results in a high-entropy alloy composite with uniform elemental distribution and no impurity phases.

[0125] In summary, this invention introduces high-entropy alloy composites as a universal electrocatalyst into various chalcogenide cathode systems (Se) in all-solid-state batteries. x S yThe introduction of HEA effectively accelerates the charge transfer process at the conductive agent / cathode / electrolyte interface and significantly improves the cathode reaction kinetics. Electronic structure analysis shows that multi-component alloying induces a significant broadening of the d-band and optimizes the electronic state distribution near the Fermi level, thereby achieving more favorable interactions with chalcogenide species. Further adsorption energy calculations and charge density difference analysis show that HEA has a strong stabilizing effect on reaction intermediates, while maintaining a moderate interaction strength with the initial reactants and final products. Therefore, the introduction of HEA significantly improves the specific capacity and cycle stability of the cathode in the all-solid-state system. In particular, the all-solid-state lithium selenide battery using HEA exhibits excellent electrochemical performance: it can still maintain approximately 750 mAh g⁻¹ after more than 1200 cycles at 1C. -1 It maintains a stable and reversible capacity with almost no capacity decay; even at a higher 2C rate, it can still maintain 657mAh g after 1800 cycles. -1 The reversible capacity corresponds to a capacity retention rate of nearly 90%. Furthermore, at higher selenium loadings (4.08 mg / cm³), [the capacity retention rate is also high]. -2 Under these conditions, the HEA-based cathode retains 91% of its initial capacity after 200 cycles. This study not only reveals the great application potential of high-entropy alloy composites in all-solid-state chalcogenide cathode systems, but also provides a universal design strategy for improving the performance of next-generation all-solid-state batteries by regulating catalyst-cathode interface interactions.

[0126] The technical features of the embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions, and variations to the above embodiments within the scope of the present invention. Furthermore, without contradiction, those skilled in the art can combine and integrate different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

Claims

1. A high-entropy alloy composite material matching the dp energy level of a chalcogenide selenium-based cathode material, characterized in that, The high-entropy alloy in the high-entropy alloy composite is Fe. a Co b Ni c Cu d Cr e Where 0.9≤a≤1.1, 0.9≤b≤1.1, 0.9≤c≤1.1, 0.9≤d≤1.1, and 0.9≤e≤1.1, the chalcogenide selenium-based cathode material is Se. x S y Where x is 0 < x ≤ 8 and y is 0 ≤ y ≤ 8; the dp energy level difference t between the high-entropy alloy and the chalcogenide selenium-based cathode material is 0.1 ≤ t ≤ 0.5; Where a, b, c, d, and e represent only the molar percentages of iron, cobalt, nickel, copper, and chromium atoms in the high-entropy alloy, respectively. x S y In this context, x and y represent the molar percentages of selenium and sulfur atoms, respectively.

2. The high-entropy alloy composite according to claim 1, characterized in that, The high-entropy alloy in the high-entropy alloy composite is loaded on a carbon support; Preferably, the raw materials for iron, cobalt, nickel, copper, and chromium in the high-entropy alloy are their corresponding metal halide or metal halide hydrate. More preferably, the raw materials for iron, cobalt, nickel, copper, and chromium in the high-entropy alloy are their corresponding metal element chloride hydrates; More preferably, the ratio of the total number of moles of the metal halide hydrate to the mass of the carbon carrier is (1~1.5) mmol: (180~220) mg.

3. The high-entropy alloy composite according to claim 1, characterized in that, The high-entropy alloy is FeCoNiCuCr.

4. The high-entropy alloy composite according to claim 1, characterized in that, The high-entropy alloy exists in the form of high-entropy alloy nanoparticles on a carbon support; Preferably, the particle size range of the high-entropy alloy nanoparticles is 10~100nm.

5. The high-entropy alloy composite according to claim 1, characterized in that, The dp energy level difference t between the high-entropy alloy and the chalcogenide selenium-based cathode material is 0.3 ≤ t ≤ 0.4; Preferably, the sulfide selenium-based cathode (Se) x S y x / y≥0.

5.

6. The high-entropy alloy composite according to claim 1, characterized in that, The high-entropy alloy has a face-centered cubic (FCC) single-phase solid solution structure; Preferably, the XRD of the high-entropy alloy has characteristic diffraction peaks corresponding to the (111), (200) and (220) crystal planes; Preferably, the lattice pattern of the high-entropy alloy has lattice fringes with spacings of 0.206 nm and 0.170 nm, respectively; Preferably, the chalcogenide selenium-based solid-state battery containing the high-entropy alloy composite operates at 2C, 1.53 mg / cm³. -2 The active material surface loading remains ≥600 mAh g after 1800 cycles. -1 The reversible capacity; Preferably, the chalcogenide selenium-based solid-state battery containing the high-entropy alloy composite operates at 1C and 1.53 mg / cm². -2 Under the surface loading of active material, the capacity retention rate after 1200 cycles is ≥95%; Preferably, the chalcogenide selenium-based solid-state battery containing the high-entropy alloy composite is used at 0.2C and 4.08 mg cm⁻¹. -2 The capacity retention rate after 200 cycles is ≥88% under the surface loading of active material.

7. A method for preparing the high-entropy alloy composite according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1: Mix the metal halide hydrates of five metals, namely iron (Fe), cobalt (Co), nickel (Ni), copper (Cu) and chromium (Cr), with a carbon support and grind them to obtain a composite precursor. S2: The composite precursor obtained in S1 is dried; placed in an inert gas atmosphere, subjected to instantaneous carbon thermal shock treatment by applying voltage, cleaned, and dried to obtain a high-entropy alloy composite.

8. The method for preparing the high-entropy alloy composite according to claim 7, characterized in that, The grinding time is 20-40 minutes; Preferably, the drying temperature is 50~70℃; Preferably, the voltage of the carbon thermal shock treatment is 80~120 V, and the duration is 0.3~0.5 seconds.

9. The method for preparing the high-entropy alloy composite according to claim 7, characterized in that, Includes the following steps: S1: Hydrated metal chlorides of iron (Fe), cobalt (Co), nickel (Ni), copper (Cu) and chromium (Cr) were selected as metal precursors. Each metal precursor salt was mixed according to the target stoichiometric ratio, thoroughly mixed with carbon support, and ground for 30 min to obtain the composite precursor. S2: The composite precursor obtained in S1 was dried at 60°C; the dried mixture was evenly spread between two pieces of carbon cloth and subjected to carbon thermal shock treatment under an argon atmosphere. During the process, a voltage of 100V was applied for 0.4s. After the thermal shock treatment, the product was thoroughly cleaned with ethanol and dried to obtain the high-entropy alloy composite.

10. The application of a high-entropy alloy composite prepared by the preparation method of any one of claims 1 to 6 or any one of claims 7 to 9 in a battery, characterized in that, The battery comprises a high-entropy alloy composite.

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