A negative electrode material, a preparation method thereof, a full-solid-state battery, and an electric device

Abstract

This invention provides an anode material and its preparation method, an all-solid-state battery, and an electrical device, specifically relating to the field of battery technology. The anode material comprises a porous silicon-carbon material and a high-entropy sulfide solid electrolyte distributed within its pores and surface. The high-entropy sulfide solid electrolyte has the general chemical formula Li. 4±x‑y A y (M1 a M2 b M3 c S4 δ X δ In the formula, 0≤x≤1.5, 0≤y≤1.5, and y≤4±x; 0.4≤a≤0.8, 0.1≤b≤0.4, 0.1≤c≤0.3, a+b+c=1, 0≤δ≤1; A is selected from one or two of Na and K; M1 is selected from one or more of Ge, Sn, Si, P, As, and B; M2 is selected from one or more of Sb, Nb, Ta, V, Mo, W, Ti, Zr, Hf, and Re; M3 is selected from one or more of Al, Ga, In, Bi, Pb, Mg, Ca, Zn, Cd, Y, Sc, La, Ba, Sr, Ce, and Sm; X is selected from one or more of O, Se, and Te. The negative electrode material of this invention can effectively improve the cycle performance and fast charging performance of the battery.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a negative electrode material and its preparation method, an all-solid-state battery, and an electrical device. Background Technology

[0002] With the market demand for high-energy-density and high-safety energy storage systems continuing to rise, all-solid-state batteries are widely recognized as an important development direction for next-generation battery technology. Among them, silicon-based anodes, with a theoretical specific capacity of up to 4200 mAh / g, far exceeding the 372 mAh / g of traditional graphite anodes, have become a key material for improving battery energy density. To alleviate the structural pulverization and cycle failure problems caused by the drastic volume expansion (>300%) of silicon during lithiation / delithiation, researchers generally adopt silicon-carbon composite structure designs. By leveraging the supporting role of the porous carbon framework, they achieve a synergistic improvement in mechanical buffering, electronic conduction, and structural stability.

[0003] Furthermore, in all-solid-state battery systems, to overcome the technical challenges of poor ion transport and interfacial contact within the electrodes, it is typically necessary to dope the electrodes with solid electrolytes; among these, sulfide solid electrolytes (such as Li3PS4, Li...) are commonly used. 10 GeP2S 12 Due to its dual advantages of high ionic conductivity at room temperature and excellent processing performance, silicon-carbon anodes (SCCAs) have become the most widely used type of solid-state electrolyte. However, integrating SCCAs with sulfide solid-state electrolytes still faces many serious challenges: 1) The rigid interface between the electrode and the electrolyte results in a limited effective contact area and high interfacial impedance; 2) Silicon particles are easily encapsulated by insulating carbon phases or voids, resulting in a lack of penetrating lithium-ion transport channels inside the electrode; 3) The repeated expansion and contraction of silicon-based materials during cycling can easily cause electrolyte particles to peel off from the active surface of the electrode; 4) Traditional sulfide electrolytes have significant stability limitations, not only easily undergoing side reactions with silicon or carbon matrices but also experiencing structural degradation under harsh conditions of high voltage and high current. These defects severely restrict the cycle performance and fast-charging performance of all-solid-state batteries, hindering their large-scale practical application. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention provides an anode material and its preparation method, an all-solid-state battery and an electrical device, so as to improve the technical problems of high interface impedance, poor ion transport and easy debonding due to volume expansion of silicon-carbon anode materials.

[0005] To achieve the above and other related objectives, the present invention provides a negative electrode material comprising: a porous silicon-carbon material and a high-entropy sulfide solid electrolyte, wherein the high-entropy sulfide solid electrolyte is distributed on the surface and within the pores of the porous silicon-carbon material; wherein the chemical formula of the high-entropy sulfide solid electrolyte is: Li 4±x-y A y (M1 a M2 b M3 c S4 δ X δ In the formula, 0≤x≤1.5, 0≤y≤1.5, and y≤4±x; 0.4≤a≤0.8, 0.1≤b≤0.4, 0.1≤c≤0.3, a+b+c=1, 0≤δ≤1; A is selected from one or two of Na and K; M1 is selected from one or more of Ge, Sn, Si, P, As, and B; M2 is selected from one or more of Sb, Nb, Ta, V, Mo, W, Ti, Zr, Hf, and Re; M3 is selected from one or more of Al, Ga, In, Bi, Pb, Mg, Ca, Zn, Cd, Y, Sc, La, Ba, Sr, Ce, and Sm; X is selected from one or more of O, Se, and Te.

[0006] In one embodiment of the present invention, in the negative electrode material, the volume of the high-entropy sulfide solid electrolyte accounts for 9% to 95% of the pore volume of the porous silicon-carbon material; the mass ratio of the porous silicon-carbon material to the high-entropy sulfide solid electrolyte is (1 to 100):1.

[0007] In one embodiment of the present invention, the D50 of the high-entropy sulfide solid electrolyte is 1 nm to 500 nm.

[0008] In one embodiment of the present invention, the mass of silicon particles in the negative electrode material accounts for 30% to 80% of the total mass of the negative electrode material.

[0009] In one embodiment of the present invention, the pore volume of the negative electrode material is 0.01 cm. 3 / g~1cm 3 / g, the average pore size of the negative electrode material is 1nm~2μm, and the specific surface area is 1m². 2 / g~800m 2 / g.

[0010] In one embodiment of the present invention, the porous silicon-carbon material has a D50 of 1 μm to 30 μm, an average pore size of 2 nm to 4 μm, and a specific surface area of ​​10 m². 2 / g~1000m 2 / g, pore volume 0.1m 3 / g~1.2m 3 / g; the porous silicon-carbon material has a micropore ratio of 1%~10%, a mesopore ratio of 40~60%, and a macropore ratio of 20%~50%.

[0011] The present invention also provides a method for preparing the above-mentioned negative electrode material, the method comprising the following steps:

[0012] A mixed solvent is prepared by mixing protic solvent and non-protic solvent in a certain proportion; A high-entropy sulfide solid electrolyte is dispersed in the mixed solvent to prepare a mixed solution; A porous silicon carbon material is added to the mixed solution and dispersed evenly to obtain a slurry; The solvent in the slurry is removed to obtain the negative electrode material; The mass ratio of the protic solvent to the aprotic solvent is 1:(1~10).

[0013] In one embodiment of the present invention, the proton solvent includes one or more of ethanol, methanol, 1,2-ethylenediamine and 1,2-ethylenedithiol.

[0014] In one embodiment of the present invention, the aprotic solvent includes one or more of toluene, xylene, benzene, acetonitrile, diethyl ether, and carbon tetrachloride.

[0015] In one embodiment of the present invention, the mass ratio of the high-entropy sulfide solid electrolyte to the mixed solvent is 1:(50~200).

[0016] The present invention also provides an all-solid-state battery, the all-solid-state battery comprising: a positive electrode, a solid electrolyte layer and a negative electrode, wherein the negative electrode comprises any of the negative electrode materials described above, or a negative electrode material prepared by the above preparation method.

[0017] The present invention also provides an electrical device comprising the above-described all-solid-state battery.

[0018] The beneficial effects of this invention are as follows: The negative electrode material provided by this invention uses porous silicon-carbon material as the matrix, and the high-entropy sulfide solid electrolyte is precisely anchored at the nanoscale to the inner pores and surface of the porous silicon-carbon material matrix, forming a three-in-one multifunctional synergistic system of "silicon active center - carbon conductive network - high-entropy sulfide ion channel", realizing the synergistic optimization of active material, electron transport and ion transport, and significantly improving the comprehensive electrochemical performance of all-solid-state battery.

[0019] 1. High-entropy sulfide solid electrolytes are uniformly dispersed in the pores of a porous silicon-carbon material matrix in the form of nanoparticles, which can form continuous, low-impedance lithium-ion transport channels. This significantly improves the interfacial ion conductivity compared to traditional structures, effectively reduces the overall impedance of all-solid-state batteries, and provides a stable guarantee for the rapid migration of lithium ions.

[0020] 2. High-entropy sulfide solid electrolytes can be firmly anchored to the pore wall surface of porous silicon-carbon material matrix, forming a tight and strong interfacial bond with silicon active particles and carbon matrix. This can effectively suppress the interfacial debonding problem caused by the drastic volume expansion of silicon during lithiation / delithiation. The interfacial impedance can still be effectively controlled after cycling, which is significantly reduced compared with traditional structures, thus maintaining interfacial stability.

[0021] 3. The porous carbon framework provides stable mechanical support for the entire anode system. The high-entropy sulfide layer loaded inside it has both moderate flexibility and excellent ion conductivity. The two work together to effectively adapt to the volume change of silicon during charging and discharging, suppress silicon particle breakage and active material shedding, and greatly improve the cycle stability of the anode material. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0023] In the attached diagram: Figure 1 A scanning electron microscope (SEM) image of a negative electrode material provided in an embodiment of the present invention; Figure 2 This is a SEM image of the negative electrode material provided in an embodiment of the present invention; Figure 3 This is a flowchart illustrating a method for preparing a negative electrode material according to an embodiment of the present invention. Detailed Implementation

[0024] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0025] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0027] In this article, the terms "multiple," "various," and "multiple times" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0028] In this document, terms such as “preferred,” “ideal,” “further,” “even more,” and “particularly” are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this invention.

[0029] In this document, when referring to numerical ranges, unless otherwise specified, the distribution of selectable values ​​within a numerical range is considered continuous, including the two endpoints of the range (i.e., the minimum and maximum values), and every value between these two endpoints. When multiple numerical ranges are provided to describe a feature or property, these numerical ranges can be combined.

[0030] The terms or phrases used in this article have the following meanings: Pore ​​volume refers to the total volume of all pores in a material.

[0031] Proton solvents are molecules containing ionizable OH, NH, or SH bonds that can release protons (H+) through self-ionization. + It actually exists in the form of solvated protons, such as H3O in water. + ( ), or a polar solvent that accepts protons through hydrogen bonds.

[0032] Aprotic solvents are solvents whose molecules lack OH, NH, and SH bonds, and therefore cannot donate protons. They can only partially function as proton acceptors (accepting protons through lone pairs of electrons).

[0033] D50, also known as median particle size, means: In the particle size distribution of a volume-based particle group, the particle size corresponding to a cumulative distribution percentage of 50% is that half of the particles in the sample have a particle size less than or equal to this value, and the other half have a particle size greater than or equal to this value.

[0034] Silicon-carbon anode materials for all-solid-state batteries still suffer from numerous unresolved defects, severely restricting the overall electrochemical performance and large-scale application of all-solid-state batteries: the electrolyte is unevenly distributed within the pores of silicon-carbon, accumulating in large quantities between particles and unable to effectively contact the active silicon; the electrode lacks penetrating ion transport channels, resulting in long lithium-ion migration paths, severe local polarization, and poor rate performance; the electrode and electrolyte have only point contact interfaces, which are prone to interface debonding during charge-discharge cycles due to the volume expansion and contraction of silicon particles, leading to a continuous increase in interface impedance; single or binary sulfide electrolytes are prone to chemical and electrochemical instability in high-silicon-content anode systems, significantly limiting battery cycle life; in addition, sulfide electrolytes are extremely sensitive to water and oxygen, and most polar solvents react with them, while traditional non-polar solvents are difficult to effectively disperse high-entropy sulfides. These defects collectively hinder the large-scale application of silicon-carbon anode materials for all-solid-state batteries.

[0035] Based on this, this application provides an anode material and its preparation method, an all-solid-state battery, and an electrical device. The anode material uses porous silicon-carbon material as a framework, with a high-entropy sulfide solid electrolyte uniformly distributed in nanoparticle form on the surface and within the pores of the porous silicon-carbon material, constructing a three-in-one multifunctional synergistic system of "silicon active center—carbon conductive network—high-entropy sulfide ion channel". This system can ensure rapid lithium-ion conduction while maintaining high electrode density and structural stability, thereby achieving high reversible capacity, excellent cycle performance, and outstanding rate capability of the anode material, effectively improving the cycle stability and fast-charging performance of the all-solid-state battery.

[0036] Please see Figure 1 and Figure 2 The negative electrode material provided by this invention includes a porous silicon-carbon material and a high-entropy sulfide solid electrolyte. The porous silicon-carbon material is a negative electrode substrate material with both porous structure and composite characteristics, formed by loading silicon-based active particles onto porous carbon. This allows for the synergistic utilization of silicon's high capacity and carbon's high conductivity and structural stability. The high-entropy sulfide solid electrolyte is uniformly distributed in the pores and surface of the porous silicon-carbon material in the form of nanoparticles, forming continuous, low-resistance lithium-ion channels and significantly reducing battery impedance. Furthermore, the porous carbon provides mechanical support, while the internal high-entropy sulfide layer possesses both flexibility and ion conductivity. These two elements work together to adapt to changes in silicon volume, suppressing silicon particle breakage and significantly improving cycle stability.

[0037] In this application, the general chemical formula of the high-entropy sulfide solid electrolyte is Li. 4±x-y A y (M1 a M2 b M3 c S4 δ X δIn the formula, 0≤x≤1.5, 0≤y≤1.5; 0.4≤a≤0.8, 0.1≤b≤0.4, 0.1≤c≤0.3, a+b+c=1, 0≤δ≤1; A is selected from one or two of Na and K; M1 is selected from one or more of Ge, Sn, Si, P, As, and B; M2 is selected from one or more of Sb, Nb, Ta, V, Mo, W, Ti, Zr, Hf, and Re; M3 is selected from one or more of Al, Ga, In, Bi, Pb, Mg, Ca, Zn, Cd, Y, Sc, La, Ba, Sr, Ce, and Sm; X is selected from one or more of O, Se, and Te.

[0038] Those skilled in the art should understand that: 4±xy in the above chemical formula represents the stoichiometric ratio of Li, where "4" represents the theoretical reference molar number of Li, "±x" represents the "non-stoichiometric floating term" of Li, x is the adjustment amount, such as intentionally adding excess Li during preparation to compensate for subsequent interface loss, or slight loss of Li during sintering, etc., x can be any value from 0 to 1.5, for example, it can be 0, 0.5, 1.0 or 1.5, etc.; y is the substitution amount of A for Li, where A can be Na, or K, or a combination of Na and K, and the value of y can be 0, 0.5, 1.0 or 1.5, etc. M1, M2, and M3 represent cations. M1 can be any one of Ge, Sn, Si, P, As, and B, such as Ge, Sn, or Si, etc. M1 can also be any combination of two or more of Ge, Sn, Si, P, As, and B, such as Ge and Sn, or P, As, and B, etc. 'a' represents the stoichiometric ratio of M1, which can be 0.4, 0.5, 0.6, 0.7, or 0.8, etc. M2 can be any one of Sb, Nb, Ta, V, Mo, W, Ti, Zr, Hf, and Re, such as Sb, Nb, or Mo, etc. M2 can also be any combination of two or more of the elements listed above, such as Sb and Ta, or W, Ti, and Zr, etc. 'b' represents the stoichiometric ratio of M2, which can be 0.1, 0.2, 0.3, or 0.4, etc. M3 can be any one of Al, Ga, In, Bi, Pb, Mg, Ca, Zn, Cd, Y, Sc, La, Ba, Sr, Ce, and Sm, for example, Al, Ga, Bi, or Mg, etc. M3 can also be any combination of two or more of the elements listed above, such as Al and Ga, or a combination of Ba, Sr, and Sm, etc. c represents the stoichiometric ratio of M3, which can be 0.1, 0.2, or 0.3, etc. It should be noted that the values ​​of a, b, and c must ensure that a + b + c = 1. X represents the position of the substituted S, and δ represents the amount of substitution of X. X can be any one of O, Se, and Te, or any combination of two or three, for example, X can be O, Se, a combination of Te and Se, or a combination of O, Se, and Te, etc. The value of δ can be 0, 0.5, or 1, etc.

[0039] The high-entropy sulfide solid electrolyte of this invention, compared with conventional sulfide solid electrolytes (such as Li3PS4, Li...), 10 GeP2S 12(etc.) It not only expands lithium-ion transport channels and reduces lithium-ion migration barriers through lattice distortion caused by disordered solid solution of polymetallic cations, significantly improving room-temperature ionic conductivity, but also efficiently adapts to the rapid lithium-ion transport requirements in silicon-carbon anodes, alleviates local polarization, and improves battery rate performance. Furthermore, it enhances structural stability and mechanical strength through high-entropy thermodynamic stabilization effects and element doping optimization, adapting to the volume expansion and contraction during the charging and discharging process of silicon-carbon anodes and preventing electrolyte particle breakage and pulverization. At the same time, it reduces interfacial side reactions with silicon and carbon matrices through multi-element synergistic regulation of surface electronic structure, broadens the electrochemical stability window, improves water and oxygen stability to extend battery cycle life, and optimizes surface polarity through element regulation to form a tight interfacial bond with porous silicon-carbon material matrix and silicon active particles, reducing interfacial impedance and ensuring interfacial stability, achieving high ionic conductivity, high structural stability, and excellent interfacial compatibility. It can ensure rapid lithium-ion transport through continuous ion channels, adapt to the volume expansion of silicon through structural optimization, and adapt to the stringent requirements of high silicon content anodes through improved stability.

[0040] The aforementioned high-entropy sulfide solid electrolyte can be prepared using the following method: First, according to the chemical formula Li 4±x-y A y (M1 a M2 b M3 c S4 δ X δ Li source, A source, M1 source, M2 source, M3 source, S source, and X source are mixed evenly according to a stoichiometric ratio, and then added to a ball mill jar for ball milling to obtain precursor powder. The ball-to-material mass ratio in the ball mill jar is 1:1 to 100:1, the ball milling time is 1 to 48 hours, and the ball milling speed is 50 to 1500 rpm. In some optional embodiments, the ball-to-material mass ratio can be 1:1, 50:1, 80:1, or 100:1, etc.; the ball milling time can be 1 hour, 12 hours, 24 hours, 36 hours, or 48 hours, etc.; and the ball milling speed can be 50 rpm, 500 rpm, 1000 rpm, or 1500 rpm, etc.

[0041] The precursor powder obtained by ball milling is then sintered at 150~500℃ for 1~12h, followed by cooling at a rate of 1~10℃ / s to obtain a high-entropy sulfide solid electrolyte. In some optional embodiments, the sintering temperature can be 150℃, 300℃, 400℃, or 500℃, etc.; the sintering time can be 1h, 6h, 10h, or 12h, etc.

[0042] The preparation method of high-entropy sulfide solid electrolytes is not limited to this; other conventional methods for preparing sulfide solid electrolytes can also be used.

[0043] In this invention, the pore volume of the negative electrode material is 0.01 cm³. 3 / g~1cm 3 / g, for example, can be 0.01cm 3 / g, 0.1cm 3 / g, 0.3cm 3 / g, 0.5 cm 3 / g, 0.8 cm 3 / g or 1 cm 3 / g, etc. The pore volume of the negative electrode material is jointly determined by the pore volume of the porous silicon-carbon material and the filling volume of the high-entropy sulfide solid electrolyte within the pores of the porous silicon-carbon material. The smaller the pore volume of the negative electrode material, the larger the filling volume of the high-entropy sulfide solid electrolyte within the pores of the porous silicon-carbon material. In this case, the remaining pore volume in the porous silicon-carbon material is extremely small, which cannot effectively buffer the volume expansion of the silicon material during charging and discharging, easily leading to silicon particle breakage, and thus affecting the cycle stability and fast-charging performance of the battery. Conversely, the larger the pore volume of the negative electrode material, the smaller the filling volume of the high-entropy sulfide solid electrolyte within the pores of the porous silicon-carbon material. The remaining pore volume in the porous silicon-carbon material is relatively large, and the high-entropy sulfide solid electrolyte cannot be effectively embedded in the pores of the porous silicon-carbon material, which will cause discontinuous lithium-ion transport paths and poor ionic conductivity, which will also have an adverse effect on the cycle performance and fast-charging performance of the battery.

[0044] In some optional embodiments, the volume of the high-entropy sulfide solid electrolyte in the negative electrode material accounts for 9% to 95% of the pore volume of the porous silicon-carbon material, for example, it can be 9%, 30%, 50%, 80%, or 95%, etc. The higher the proportion of the high-entropy sulfide solid electrolyte to the pore volume of the porous silicon-carbon material, the smaller the remaining pore volume of the porous silicon-carbon material, and the smaller the pore volume of the negative electrode material; conversely, the lower the proportion of the high-entropy sulfide solid electrolyte to the pore volume of the porous silicon-carbon material, the larger the remaining pore volume of the porous silicon-carbon material, and the larger the pore volume of the negative electrode material.

[0045] In some optional embodiments, the mass ratio of porous silicon-carbon material to high-entropy sulfide solid electrolyte is (1~100):1, for example, it can be 1:1, 30:1, 50:1, 80:1, or 100:1, etc. The silicon-carbon ratio of the porous silicon-carbon material is fixed, and the mass fraction of silicon particles it contains is constant. Therefore, the ratio of porous silicon-carbon material to high-entropy sulfide solid electrolyte directly determines the mass content of silicon particles in the anode material. As the core active component in the anode material, the mass content of silicon particles directly relates to the core performance of the entire battery and forms a mutually restrictive relationship with the function of the high-entropy sulfide solid electrolyte. Specifically, if the mass content of silicon particles is low, it means that the proportion of porous silicon-carbon material in the anode material is insufficient and the proportion of high-entropy sulfide solid electrolyte is high. In this case, the number of silicon particles, which are the active centers for lithium intercalation, is insufficient, which directly leads to a decrease in the reversible lithium intercalation capacity of the anode material, resulting in a low energy density of the entire battery and failing to leverage the core advantage of high capacity of silicon-based anodes. Conversely, if the mass content of silicon particles is high... This indicates an excessively high proportion of porous silicon-carbon material and an insufficient proportion of high-entropy sulfide solid electrolyte. The high-entropy sulfide solid electrolyte is a key component for constructing continuous ion transport channels within the negative electrode, adapting to silicon volume expansion, and reducing interfacial impedance. Insufficient content leads to the inability to form a complete lithium-ion transport network, hindering lithium-ion migration, exacerbating local polarization, and failing to effectively buffer the drastic volume expansion during silicon particle lithiation / delithiation, easily causing interfacial debonding and silicon particle breakage. Ultimately, this results in a significant deterioration in battery cycle stability and rate performance, failing to meet the synergistic requirements of high capacity and high stability in all-solid-state batteries. Therefore, the ratio of porous silicon-carbon material to high-entropy sulfide solid electrolyte needs precise control to achieve a balance between the active capacity of silicon particles and the function of the electrolyte. Furthermore, the mass content of silicon particles in the negative electrode material should be 30%~80% (the percentage of silicon particles to the total mass of the negative electrode material), for example, 30%, 50%, 70%, or 80%, etc.

[0046] In some optional embodiments, the D50 particle size of the high-entropy sulfide solid electrolyte is 1 nm to 500 nm, specifically 1 nm, 50 nm, 100 nm, 200 nm, 400 nm, or 500 nm, etc. Further, the D50 particle size of the high-entropy sulfide solid electrolyte is 5 nm to 300 nm, specifically 5 nm, 80 nm, 150 nm, 230 nm, or 300 nm, etc.

[0047] In some alternative embodiments, the average pore size of the negative electrode material is 1 nm to 2 μm, specifically 1 nm, 100 nm, 500 nm, 1 μm, 1.5 μm, or 2 μm, etc.; the specific surface area of ​​the negative electrode material is 1 m². 2 / g~800m 2 / g, specifically 1 m 2 / g、100 m 2 / g、300 m 2 / g、500 m 2 / g、700 m 2 / g or 800 m 2 / g, etc. The average pore size and specific surface area of ​​the negative electrode material can be obtained by testing with a Micromeritics ASAP 2020 gas adsorption analyzer.

[0048] Porous silicon-carbon materials are commercially available or prepared using conventional methods in the art. In some optional embodiments, the porous silicon-carbon material satisfies one or more of the following conditions: (a) the D50 particle size of the porous silicon-carbon material is 1 μm to 30 μm, for example, 1 μm, 10 μm, 20 μm, or 30 μm, etc.; (b) the average pore size of the porous silicon-carbon material is 2 nm to 4 μm, for example, 2 nm, 1 μm, 2 μm, 3 μm, or 4 μm, etc.; (c) the specific surface area of ​​the porous silicon-carbon material is 10 m². 2 / g~1000m 2 / g, for example, can be 10 m 2 / g、100 m 2 / g、500 m 2 / g、800 m 2 / g or 1000m 2 / g etc. (d) The pore volume of porous silicon carbide material is 0.1m. 3 / g~1.2m 3 / g, specifically 0.1m 3 / g, 0.5m 3 / g, 0.8m 3 / g, 1.0m 3 / g or 1.2m 3 / g, etc. (e) In porous silicon-carbon materials, the particle size of silicon particles is 1nm~100nm, for example, it can be 1nm, 30nm, 50nm, 80nm or 100nm, etc. (f) The proportion of micropores in porous silicon-carbon materials is 1%~10%, for example, it can be 1%, 3%, 5%, 7% or 10%, etc. (g) The proportion of mesopores in porous silicon-carbon materials is 40%~60%, for example, it can be 40%, 50% or 60%, etc. (h) The proportion of macropores in porous silicon-carbon materials is 20%~50%, for example, it can be 20%, 30%, 40% or 50%, etc. It should be noted that: micropores refer to pore structures with an equivalent diameter of less than 2 nm; mesopores refer to pore structures with an equivalent diameter between 2nm and 50 nm; macropores refer to pore structures with an equivalent diameter greater than 50 nm.

[0049] Please see Figure 3 The present invention also provides a method for preparing the above-mentioned negative electrode material, the method comprising the following steps: S1. Mix the protic solvent and the non-protic solvent in a certain proportion to obtain a mixed solvent; S2. Disperse the high-entropy sulfide solid electrolyte in a mixed solvent to prepare a mixed solution; S3. Add porous silicon carbon material to the mixed solution and disperse it evenly to obtain a slurry; S4. Remove the solvent from the slurry to obtain the negative electrode material.

[0050] Specifically, the proton solvent in step S1 includes one or more of ethanol, methanol, 1,2-ethylenediamine, and 1,2-ethylenedithiol. That is, the proton solvent can be selected from any one of the solvents listed above, or from any combination of two or more of the solvents listed above. For example, the proton solvent is ethanol, or methanol, or a mixture of methanol and 1,2-ethylenediamine, etc.

[0051] Aprotic solvents include one or more of toluene, xylene, benzene, acetonitrile, diethyl ether, and carbon tetrachloride. That is, an aprotic solvent can be selected from any one of the solvents listed above, or from any combination of two or more of the solvents listed above. For example, the aprotic solvent can be toluene, or xylene, or a mixture of toluene and acetonitrile, or a mixture of acetonitrile and diethyl ether, etc.

[0052] Step S1 involves mixing a proton solvent and a non-proton solvent in a specific ratio to prepare a mixed solvent. The proton solvent in the mixed solvent provides limited but necessary solvation capability, helping to break down the lattice or glass network structure of the solid electrolyte. Specifically, the proton solvent can react with cations in the electrolyte (such as Li₂)... + The protons bind through dipole interactions or weak hydrogen bonds, or form weak hydrogen bonds with sulfide anions, thereby reducing the free energy of ions in the system and promoting efficient dissolution of solid electrolytes. Aprotic solvents are used to dilute the protic solvent in the mixed solvent system, reducing its effective activity, thus significantly slowing down or even inhibiting the reaction between the protic solvent and sulfide anions. 2-The hydrolysis or decomposition reactions between the proton solvent and the electrolyte ensure the stability of the dissolved system. After the solid electrolyte is dissolved, the solubility of the system gradually decreases as the proton solvent evaporates, causing the sulfide electrolyte to precipitate from the solution. At this time, the non-proton solvent can be adsorbed on the surface of the precipitated electrolyte particles, inhibiting the rapid aggregation and growth of nanoparticles by providing steric hindrance or charge repulsion, thereby facilitating the acquisition of nano-sized products and maintaining their good dispersibility. In some optional embodiments, the mass ratio of proton solvent to non-proton solvent is controlled at 1:(1~10), with exemplary ratios including but not limited to 1:1, 1:3, 1:5, 1:7, and 1:10. It should be noted that the proportion of proton solvent in the mixed solvent needs to be precisely controlled: if the proportion of proton solvent is too low, the solubility performance of the mixed solvent for the high-entropy sulfide solid electrolyte will decrease, thereby affecting the particle size uniformity of the electrolyte particles and ultimately affecting the pore volume ratio of the porous silicon-carbon material matrix; if the proportion of proton solvent is too high, it will interfere with the subsequent electrolyte precipitation process, resulting in abnormal particle morphology and thus affecting the overall performance of the negative electrode material.

[0053] Step S2 involves dispersing the high-entropy sulfide solid electrolyte in the mixed solvent obtained in step S1, and stirring to completely dissolve the high-entropy sulfide solid electrolyte to obtain a mixed solution. In the mixed solution, the mass ratio of the high-entropy sulfide solid electrolyte to the mixed solvent is 1:(50~200), for example, it can be 1:50, 1:100, 1:150, or 1:200, etc.; the viscosity of the mixed solution is 1 mPa•s~500 mPa•s, for example, it can be 1 mPa•s, 50 mPa•s, 100 mPa•s, 300 mPa•s, or 500 mPa•s, etc. The viscosity of the mixed solution can be adjusted by regulating the ratio of the high-entropy sulfide solid electrolyte to the solvent.

[0054] Step S3 involves adding porous silicon carbon material to the mixed solution and stirring thoroughly until homogeneous to obtain a slurry. The mass ratio of the porous silicon carbon material to the high-entropy sulfide solid electrolyte is (1~100):1, for example, 1:1, 1:50, or 1:100, etc.

[0055] Step S4 involves removing the solvent from the slurry by heating at a temperature of 25~200℃, specifically 25℃, 50℃, 100℃, 150℃, or 200℃, etc. The heating time is not limited, as long as the solvent is completely removed from the slurry. After heating, the desired negative electrode material is obtained.

[0056] The preparation method of the present invention uses solvent evaporation-induced in-situ precipitation, which can firmly anchor high-entropy sulfide particles to the pore walls of porous silicon-carbon materials, forming a strong interfacial bond with silicon / carbon, and effectively resisting debonding caused by silicon volume expansion.

[0057] The present invention also provides an all-solid-state battery, which includes a positive electrode, a solid electrolyte layer and a negative electrode. The negative electrode includes the aforementioned negative electrode material. The solid electrolyte layer is disposed between the positive electrode and the negative electrode to provide a channel for ion transport between the positive and negative electrodes, while blocking electron transport, thereby avoiding short circuits.

[0058] Specifically, the positive electrode sheet includes a positive current collector and a positive active material layer disposed on at least one side of the positive current collector. The positive current collector is, for example, aluminum foil or carbon-coated aluminum foil, and has two surfaces disposed opposite to each other along its thickness direction. The positive active material layer can be disposed on one surface of the positive current collector or simultaneously on both surfaces. The positive active material layer includes a positive active material, a solid electrolyte, a conductive agent, and a binder. The positive active material includes, but is not limited to, one or more of lithium nickel cobalt manganese oxide (NCM), lithium nickel oxide (LNO), lithium manganese oxide (LMO), lithium nickel manganese oxide (LNMO), lithium cobalt oxide (LCO), and lithium nickel cobalt aluminum oxide (NCA). That is, the positive active material can be a single material, such as lithium cobalt oxide, or lithium nickel cobalt manganese oxide, or lithium nickel manganese oxide, etc.; or it can be a combination of multiple materials, such as a combination of lithium cobalt oxide and lithium nickel oxide, a combination of lithium nickel cobalt aluminum oxide, lithium-rich oxide, and lithium nickel cobalt manganese oxide, etc. The solid electrolyte is the high-entropy sulfide solid electrolyte provided in this application, but conventional solid electrolytes such as oxide solid electrolytes, sulfide solid electrolytes, and halide solid electrolytes can also be used. The conductive agent includes one or more of graphite, graphene, carbon black, carbon fiber, and carbon nanotubes, such as graphite, or a combination of carbon black and carbon fiber, etc. The adhesives include one or more of the following: hydrogenated nitrile rubber, polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyvinylpyrrolidone (PVP), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyacrylic acid (PAA), polyurethane, polyvinyl alcohol (PVA), sodium alginate (Alg), ethylene-propylene-diene monomer, styrene-butadiene rubber, polyvinylidene fluoride, fluororubber, β-cyclodextrin polymer (β-CDp), polypropylene emulsion (LA132), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE), fluorinated ethylene-propylene copolymer (FEP), perfluoroalkoxy resin (PFA), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polyvinylidene fluoride-hexafluoropropylene copolymer, and polyvinylidene fluoride-trifluorochloroethylene copolymer.

[0059] The preparation method of the positive electrode sheet is as follows: the positive active material, solid electrolyte, conductive agent and binder are thoroughly mixed in a solvent such as xylene according to a set ratio, and then coated on the positive current collector. After drying and cold pressing, the positive electrode sheet is obtained.

[0060] The solid electrolyte layer includes a solid electrolyte, which is the aforementioned high-entropy sulfide solid electrolyte. In other optional embodiments, the solid electrolyte may also be an oxide solid electrolyte, a sulfide solid electrolyte, a halide solid electrolyte, etc. The solid electrolyte layer is obtained by cold pressing the solid electrolyte.

[0061] The negative electrode sheet includes a negative current collector and a negative active material layer disposed on at least one side of the negative current collector. The negative current collector is, for example, a copper foil or a carbon-coated copper foil, and has two surfaces disposed opposite to each other along its thickness direction. The negative active material layer can be disposed on one surface of the negative current collector or simultaneously on both surfaces. The negative active material layer includes the negative electrode material, conductive agent, and binder described above in this invention. The conductive agent includes one or more of graphite, graphene, carbon black, carbon fiber, and carbon nanotubes, for example, graphite, or a combination of carbon black and carbon fiber, etc. The adhesives include one or more of the following: hydrogenated nitrile rubber, polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyvinylpyrrolidone (PVP), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyacrylic acid (PAA), polyurethane, polyvinyl alcohol (PVA), sodium alginate (Alg), ethylene-propylene-diene monomer, styrene-butadiene rubber, polyvinylidene fluoride, fluororubber, β-cyclodextrin polymer (β-CDp), polypropylene emulsion (LA132), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE), fluorinated ethylene-propylene copolymer (FEP), perfluoroalkoxy resin (PFA), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polyvinylidene fluoride-hexafluoropropylene copolymer, and polyvinylidene fluoride-trifluorochloroethylene copolymer.

[0062] The preparation method of the negative electrode sheet is as follows: The negative electrode material, conductive agent and binder are thoroughly mixed in a solvent such as xylene according to a set ratio, and then coated onto the negative electrode current collector. After drying and cold pressing, the negative electrode sheet is obtained.

[0063] All-solid-state battery assembly: The positive and negative electrode plates are placed on both sides of the solid electrolyte layer, pressed together, and sealed to obtain an all-solid-state battery. The assembly process is completed in a glove box under an inert atmosphere.

[0064] It should be noted that the structures not described in detail in the above batteries can be set up with reference to conventional techniques in this field, and will not be elaborated here.

[0065] The present invention also provides an electrical device comprising the above-mentioned all-solid-state battery, wherein the all-solid-state battery may be used in the form of a single cell, a battery module, or a battery pack to power the electrical device.

[0066] In some embodiments, the electrical device includes mobile phones, tablets, laptops, electric toys, electric vehicles, new energy vehicles, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc., but are not limited to these.

[0067] The technical solution of the present invention will be described in detail below through several specific embodiments and comparative examples. Unless otherwise stated, the raw materials and reagents used in the following embodiments are all commercially available products, or can be prepared by conventional methods in the art, and the instruments used in the embodiments are all commercially available.

[0068] Example 1 This embodiment provides a negative electrode material, which comprises a porous silicon-carbon material and a high-entropy sulfide solid electrolyte. The porous silicon-carbon material has a silicon content of 50%, a micropore content of 2%, a mesopore content of 50%, a macropore content of 48%, and a pore volume of 1.2 cm³. 3 / g, specific surface area is 800m² 2 / g, with an average pore size of 700nm, a D50 particle size of 10μm, and a D50 particle size of 30nm for silicon particles; the high-entropy sulfide solid electrolyte is Li 3.46 (Sn 0.1 Si 0.35 P 0.55 ) 0.6 Sb 0.2 Al 0.2 S4.

[0069] The preparation method of the negative electrode material in this embodiment is as follows: (1) Preparation of high-entropy sulfide solid electrolyte: Under an argon atmosphere, 1.73 mol Li₂S, 0.06 mol SnS₂, 0.21 mol SiS₂, 0.33 mol P₂S₅, 0.1 mol Sb₂S₅, and 0.1 mol Al₂S₃ were placed in a ball mill jar, and grinding balls were added at a ball-to-material mass ratio of 30:1. The mixture was ball-milled at 100 rpm for 10 minutes, and then ball-milled at 600 rpm for 16 hours to obtain a uniformly mixed precursor material. The precursor material was placed in a crucible and sintered at 200 °C for 20 hours. After cooling at a rate of 5 °C / s, Li₂S₅ was obtained. 3.46 (Sn 0.1 Si 0.35 P 0.55 ) 0.6 Sb 0.2 Al 0.2 S4 electrolyte material, and Li with a D50 of 500 nm was obtained by sieving. 3.46 (Sn 0.1 Si 0.35 P 0.55 ) 0.6 Sb 0.2 Al 0.2 S4 electrolyte material.

[0070] (2) Preparation of negative electrode material: Take 1g Li 3.46 (Sn 0.1 Si 0.35 P 0.55 ) 0.6 Sb 0.2 Al 0.2 The S4 electrolyte material was added to 100g of a mixed solvent of ethanol and acetonitrile (ethanol:acetonitrile mass ratio 1:9). After stirring until the electrolyte material was completely dissolved, a mixed solution with a viscosity of 5 mPa•s was obtained. Then, 100g of porous silicon-carbon material was added, and the mixture was stirred at 600 rpm for 2 hours to obtain a slurry. The slurry was stirred until homogenized, and then heated to 120℃ while stirring to remove the solvent, yielding the negative electrode material. The preparation parameters of this negative electrode material are shown in Table 1, and the physicochemical properties are shown in Table 2.

[0071] This embodiment also provides an all-solid-state battery containing the above-mentioned negative electrode material, the specific composition of which is as follows: Positive electrode: LiNi 0.8 Co 0.1 Mn 0.1 O2, the above-mentioned electrolyte material Li 3.46 (Sn 0.1 Si 0.35 P 0.55 ) 0.6 Sb 0.2 Al0.2 S4, conductive agent carbon fiber, and binder hydrogenated nitrile rubber are thoroughly mixed in a xylene solvent system at a mass ratio of 70:25:2:3. The mixture is then coated onto aluminum foil, dried, and cold-pressed to obtain a positive electrode sheet with an areal capacity of 4 mAh / cm². 2 And cut it into round pieces with a diameter of 10mm.

[0072] Negative electrode sheet: 2 wt% SBR binder was dispersed in xylene and stirred to obtain a binder solution; 96 wt% of the negative electrode material prepared above, 2 wt% acetylene black, and the binder solution were added and mixed thoroughly to obtain a negative electrode slurry; the negative electrode slurry was coated onto the negative electrode current collector copper foil, dried, and cold-pressed to obtain the negative electrode sheet with an areal capacity of 4.4 mAh / cm². 2 And cut it into round pieces with a diameter of 10mm.

[0073] Solid electrolyte layer: 50 mg of the high-entropy sulfide solid electrolyte material prepared above was cold-pressed at 360 MPa to prepare an electrolyte layer with a thickness of 300 μm and a diameter of 10 mm.

[0074] Battery assembly: The positive and negative electrode sheets were placed at both ends of the solid electrolyte layer, pressed at 500 MPa, and then sealed to obtain an all-solid-state battery. The assembly process of the all-solid-state battery was completed in a glove box with an inert atmosphere.

[0075] Example 2 The difference between this embodiment and Embodiment 1 is that the mass ratio of porous silicon-carbon material to solid electrolyte is 50:1.

[0076] Example 3 The difference between this embodiment and Embodiment 1 is that the mass ratio of porous silicon-carbon material to solid electrolyte is 10:1.

[0077] Example 4 The difference between this embodiment and Embodiment 1 is that the mass ratio of porous silicon-carbon material to solid electrolyte is 1:1.

[0078] Example 5 The difference between this embodiment and Embodiment 3 is that the temperature during solvent removal in the preparation process is 25°C.

[0079] Example 6 The difference between this embodiment and Embodiment 3 is that the temperature during solvent removal in the preparation process is 60°C.

[0080] Example 7 The difference between this embodiment and Embodiment 3 is that the temperature during solvent removal in the preparation process is 100°C.

[0081] Example 8 The difference between this embodiment and Embodiment 3 is that the temperature during solvent removal in the preparation process is 200°C.

[0082] Example 9 The difference between this embodiment and Example 3 is that, during the preparation process, the mass ratio of ethanol to acetonitrile in the mixed solvent is 1:10.

[0083] Example 10 The difference between this embodiment and Example 3 is that, during the preparation process, the mass ratio of ethanol to acetonitrile in the mixed solvent is 1:7.

[0084] Example 11 The difference between this embodiment and Example 3 is that, during the preparation process, the mass ratio of ethanol to acetonitrile in the mixed solvent is 1:1.

[0085] Example 12 The difference between this embodiment and Embodiment 3 is that the high-entropy sulfide solid electrolyte is Li. 3.9 Si 0.6 (Sb 0.5 Mo 0.2 W 0.3 ) 0.2 Al 0.2 S4; Li was prepared by using 1.95 mol Li₂S, 0.6 mol SiS₂, 0.05 mol Sb₂S₅, 0.04 mol MoS₃, 0.06 mol WS₃, and 0.1 mol Al₂S₃. 3.9 Si 0.6 (Sb 0.5 Mo 0.2 W 0.3 ) 0.2 Al 0.2 S4.

[0086] Example 13 The difference between this embodiment and Embodiment 3 is that the high-entropy sulfide solid electrolyte is Li. 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S4; Li was prepared by using 2.02 mol Li₂S, 0.6 mol SiS₂, 0.1 mol Sb₂S₅, 0.03 mol Al₂S₃, 0.05 mol In₂S₃, and 0.04 mol SrS. 4.04 Si0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S4.

[0087] Example 14 The difference between this embodiment and Embodiment 3 is that the high-entropy sulfide solid electrolyte is Li. 3.8 Na 0.1 K 0.1 Si 0.6 Sb 0.2 Al 0.2 S4; Li was prepared by using 1.9 mol Li₂S, 0.05 mol Na₂S, 0.05 mol K₂S, 0.6 mol SiS₂, 0.1 mol Sb₂S₅, and 0.1 mol Al₂S₃. 3.8 Na 0.1 K 0.1 Si 0.6 Sb 0.2 Al 0.2 S4.

[0088] Example 15 The difference between this embodiment and Embodiment 3 is that the high-entropy sulfide solid electrolyte is Li4Si. 0.6 Sb 0.2 Al 0.2 S 3.7 O 0.2 Te 0.1 ; Li₄Si was prepared by using 1.7 mol Li₂S, 0.6 mol SiS₂, 0.1 mol Sb₂S₅, 0.1 mol Al₂S₃, 0.2 mol Li₂O, and 0.1 mol Li₂Te. 0.6 Sb 0.2 Al 0.2 S 3.7 O 0.2 Te 0.1 .

[0089] Example 16 The difference between this embodiment and Example 3 is that a mixed solvent of methanol and acetonitrile in a mass ratio of 1:9 is used in the preparation process.

[0090] Example 17 The difference between this embodiment and Example 3 is that, in the preparation process, a mixed solvent of ethanol and toluene in a mass ratio of 1:9 is used.

[0091] Example 18 The difference between this embodiment and Example 3 is that, in the preparation process, a mixed solvent of ethanol and carbon tetrachloride in a mass ratio of 1:9 is used.

[0092] Example 19 The difference between this embodiment and Example 3 is that, during the preparation process, the mass ratio of ethanol to acetonitrile in the mixed solvent is 3:2.

[0093] Example 20 The difference between this embodiment and Embodiment 3 is that the temperature during solvent removal in the preparation process is 20°C.

[0094] Example 21 The difference between this embodiment and Embodiment 3 is that the mass ratio of porous silicon-carbon material to solid electrolyte is 110:1.

[0095] Example 22 The difference between this embodiment and Embodiment 3 is that the mass ratio of porous silicon-carbon material to solid electrolyte is 2:3.

[0096] Comparative Example 1 The difference between this comparative example and Example 3 is that acetonitrile was used as the solvent in the preparation process.

[0097] Comparative Example 2 The difference between this comparative example and Example 3 is that the electrolyte is Li4SnS4. The electrolyte prepared by using 2 mol Li₂S and 1 mol SnS₂ has the chemical formula Li₄SnS₄.

[0098] Table 1: Process parameters for the preparation of Examples 1-22 and Comparative Examples 1-2

[0099] Table 2: Properties of negative electrode materials and battery performance of Examples 1-22 and Comparative Examples 1-2

[0100] Physicochemical performance testing (1) D50 particle size test: The D50 particle size of the porous silicon carbide material was tested using a HELOS-RODOS dry laser particle size analyzer. The test results are recorded in Table 2.

[0101] The D50 particle size of solid electrolyte particles was tested as follows: the solid electrolyte was dissolved in a mixed solvent of protic and non-protic solvents to obtain solid electrolyte powder; the D50 particle size was measured using a HELOS-RODOS dry laser particle size analyzer, and the test results are recorded in Table 2. The types of mixed solvents and the dissolution methods and conditions correspond to those in the various examples and comparative examples, and the test results are recorded in Table 1.

[0102] (2) Testing of specific surface area and pore volume: The specific surface area and pore volume of the negative electrode materials in Examples 1-22 and Comparative Examples 1-2 were tested, and the percentage of the volume of solid electrolyte particles in the negative electrode material relative to the pore volume of the porous silicon-carbon material matrix was calculated. The testing and calculation methods are as follows: The test was conducted using a Micromeritics ASAP 2020 gas adsorption instrument. During the test, the relative pressure (P / P0, where P0 is the saturated vapor pressure of N2 at liquid nitrogen temperature) was adjusted step by step, gradually increasing from a low pressure (e.g., P / P0=0.01) to near saturation (P / P0≈0.995). The volume of N2 adsorbed by the sample at each pressure point (volume at standard temperature and pressure, STP) was recorded using a pressure sensor and gas volume meter.

[0103] Specific surface area calculation: Selecting a linear interval where P / P0 is between 0.05 and 0.3, the specific surface area is calculated using the BET equation:

[0104] Where V is the adsorption volume, V m Let C be the monolayer adsorption volume, and C be a constant.

[0105] Orifice capacity calculation: When P / P0≈0.995, the adsorption capacity approaches saturation, at which point the adsorption volume (V) is... total Corresponding total pore volume (unit: cm) 3 / g):

[0106] First, measure the pore volume of the negative electrode material using the method described above, and record it as V1. Then, wash away the solid electrolyte with ethanol and measure the pore volume again, and record it as V2. The percentage of the volume of the solid electrolyte particles to the pore volume of the porous silicon-carbon material matrix is ​​(V2-V1) / V2. The calculation results are recorded in Table 2.

[0107] (3) Test method for average aperture The anode materials of Examples 1-22 and Comparative Examples 1-2 were dried, evacuated, filled with mercury, and the initial mercury volume was recorded. The pressure was gradually increased (0.1–400 MPa), and the amount of mercury infiltration under different pressures was recorded.

[0108] The average aperture was calculated using the following formula, and the results are recorded in Table 2:

[0109] Where γ = 485 mN / m, θ = 140 o P i Different pressure points (Pa) within the range of 0.1–400 MPa.

[0110]

[0111] D i : The orifice diameter corresponding to the i-th pressure point; ΔV i : The increase in mercury penetration volume in the i-th pressure zone; n: The total number of pressure zones.

[0112] (4) Calculation method for the mass content of silicon particles in the negative electrode material = mass of silicon in the porous silicon-carbon material / (porous silicon-carbon material + high-entropy sulfide solid electrolyte): Electrochemical performance testing: (1) Cycle count test At 25°C, the all-solid-state batteries assembled in each embodiment and comparative example were subjected to a low pressure of 3 MPa, activated for 2 cycles at a rate of 0.05C within an operating voltage range of 2.5~4.3V, and then charged and discharged at a rate of 1C / 1C (1C rated current density is 4 mA / cm²). 2 Record the discharge capacity of the battery in the first cycle after activation. Cycle the battery through full charge and discharge until the battery discharge capacity drops to less than or equal to 80% of the first 1C discharge capacity (80% State of Health, 80% SOH). Record the number of 1C / 1C room temperature cycles. The test results are recorded in Table 2.

[0113] (3) Rate performance (fast charging capacity retention rate) At 25°C, the all-solid-state batteries assembled in each embodiment and comparative example were subjected to a low pressure of 3 MPa, operating at a voltage of 2.5–4.3 V, and at a current density of 0.05C (1C rated current density is 4 mA / cm²). 2Activate the battery at the specified rate for 2 cycles. Charge the solid-state battery in constant current / constant voltage mode at a constant rate of 0.33C; after resting for 5 minutes, discharge the battery to the lower limit of the operating cutoff voltage at a constant rate of 0.33C; repeat the above steps for three charge-discharge cycles, and record the discharge capacity C in the third cycle. 0.33 Charge the solid-state battery at a constant current and constant voltage (DCV) mode with a constant current rate of 0.33C; after resting for 5 minutes, discharge the battery to the lower limit of the operating cutoff voltage with a constant current rate of 0.5C; repeat the above charge-discharge cycle three times. Charge the solid-state battery at a constant current and constant voltage (DCV) mode with a constant current rate of 0.33C; after resting for 5 minutes, discharge the battery to the lower limit of the operating cutoff voltage with a constant current rate of 1C; repeat the above charge-discharge cycle three times. Charge the solid-state battery at a constant current and constant voltage (DCV) mode with a constant current rate of 0.33C; after resting for 15 minutes, discharge the battery to the lower limit of the operating cutoff voltage with a constant current rate of 2C; repeat the above charge-discharge cycle three times, and record the discharge capacity C2 in the third cycle.

[0114] The capacity retention rate of high-rate 2C fast charging was calculated using the following formula, and the test results are recorded in Table 2: Fast charging capacity retention rate (%) = (C2 / C) 0.33 )×100%.

[0115] Please refer to Tables 1 and 2. The following conclusions can be drawn from the test data in the tables: The anode materials prepared in Examples 1-22, when applied to all-solid-state batteries, all achieved over 300 battery cycle times and maintained over 69% fast-charging capacity. In some preferred embodiments, the battery cycle times could be further increased to over 600, and the fast-charging capacity retention rate could reach over 90%. These test results fully demonstrate that the anode material of this invention successfully constructs a continuous and efficient nanoscale solid electrolyte ion transport network, effectively improving the overall ionic conductivity of the entire electrode material, significantly reducing the interfacial impedance between the silicon-carbon active material and the solid electrolyte, and significantly optimizing the lithium-ion transport kinetics. Simultaneously, its unique "embedded & encapsulated" structure effectively mitigates the damage to the interfacial contact caused by the volume expansion of silicon during charge-discharge cycles, thereby enabling the obtained silicon-carbon composite anode material to exhibit excellent comprehensive electrochemical performance in all-solid-state batteries.

[0116] Comparative Example 1 used a pure aprotic solvent as the solvent to disperse the high-entropy sulfide solid electrolyte. In the resulting negative electrode material, the volume percentage of the high-entropy sulfide solid electrolyte particles to the pore volume of the porous silicon-carbon material was 0. Correspondingly, the cycle performance and fast-charging capacity retention of its all-solid-state battery were significantly different from those of the other examples. The core reason for this difference is that the low pore volume percentage prevents the solid electrolyte particles from effectively embedding into the internal channels of the porous silicon-carbon material matrix. This prevents the construction of a continuous lithium-ion transport network within the porous silicon-carbon material, resulting in discontinuous ion transport paths, poor overall ionic conductivity of the electrode, and significantly affecting the battery's cycle stability and fast-charging performance.

[0117] In Examples 1-4 and 21-22, while maintaining all other conditions identically, the percentage of high-entropy sulfide solid electrolyte particles in the pore volume of the porous silicon-carbon material (pore volume ratio) was precisely controlled by adjusting the mass ratio of porous silicon-carbon material to high-entropy sulfide solid electrolyte. Test results show that, within a certain range, as the pore volume ratio of the high-entropy sulfide solid electrolyte particles increases, the cycle performance and fast-charge capacity retention of the prepared all-solid-state battery both show a certain degree of improvement. Specifically, when the mass ratio of porous silicon-carbon material to high-entropy sulfide solid electrolyte is 10:1, the battery exhibits superior overall electrochemical performance. When the percentage of the volume of the high-entropy sulfide solid electrolyte particles in the pore volume of the porous silicon-carbon material is too high (Example 22), it indicates that the high-entropy sulfide solid electrolyte particles almost fill the internal channels of the porous silicon-carbon material. Correspondingly, the cycle performance and fast-charge capacity retention of the all-solid-state battery show a significant decrease compared to other examples. This is because: after the high-entropy sulfide solid electrolyte particles almost fill the pores of the porous silicon-carbon material, the remaining pore volume in the porous silicon-carbon material is extremely small, which cannot provide sufficient buffer space for the volume expansion of the silicon material during the charge-discharge cycle of the negative electrode material. This can easily lead to the breakage of silicon particles and the pulverization of the electrode structure, ultimately significantly deteriorating the cycle stability and fast-charging performance of the battery. Figure 1 and Figure 2 The images shown are SEM images of the negative electrode material prepared in Example 3 at different magnifications. The 20,000x magnified SEM image clearly shows that the high-entropy sulfide solid electrolyte particles are uniformly dispersed in the porous silicon-carbon material matrix, occupying only a portion of the volume of the porous silicon-carbon material's pores and not completely filling them. This reasonable filling state balances lithium-ion transport efficiency with silicon volume expansion buffer space, thus enabling the all-solid-state battery to exhibit good cycle performance and fast-charging performance.

[0118] Examples 3, 5-8, and 20, while maintaining all other conditions identical, controlled the percentage of high-entropy sulfide solid electrolyte particles in the porous silicon-carbon material's pore volume by adjusting the solvent removal temperature. Test results show that the anode material described in this invention can be successfully prepared at different solvent removal temperatures. When solvent removal is performed at 120°C, the prepared anode material exhibits superior overall electrochemical performance when applied to an all-solid-state battery. When the solvent removal temperature is too high or too low, the overall battery performance decreases. This is because during solvent removal, as the temperature increases, the proton solvent in the system rapidly evaporates and decreases, leading to a sharp decrease in the solubility of the high-entropy sulfide solid electrolyte. The system reaches a high supersaturation state in a short time, at which point the nucleation rate of the electrolyte is significantly higher than the crystal growth rate, resulting in the generation of a large number of fine crystal nuclei and ultimately small-sized solid electrolyte particles. Small-diameter solid electrolyte particles are more easily and uniformly embedded in the internal channels of porous silicon-carbon material matrix, which can construct a more continuous and unobstructed lithium-ion conduction path, thereby improving the cycle performance and fast-charging performance of all-solid-state batteries. It should be noted that the solvent removal temperature should not be too high, otherwise it will have an adverse effect on the morphology of electrolyte particles and the interface bonding effect.

[0119] In Examples 3, 9-11, and 19, while maintaining identical preparation conditions, the percentage of solid electrolyte particles in the porous silicon-carbon material's pore volume was controlled by adjusting the mass ratio of proton solvent to non-proton solvent. All test groups produced anode materials with excellent performance. When the mass ratio of proton solvent to non-proton solvent was 1:9, the prepared anode material exhibited superior overall electrochemical performance when applied to an all-solid-state battery. This is because in the mixed solvent system, the proton solvent primarily dissolves the high-entropy sulfide solid electrolyte, helping to break down the electrolyte lattice and promote its complete dissolution; the non-proton solvent acts like a surfactant, inducing the orderly precipitation of nanoscale electrolyte particles and adsorbing onto the particle surface to inhibit aggregation. If the proportion of proton solvent is too high, it will interfere with the normal precipitation process of the electrolyte, resulting in uneven particle morphology and thus affecting the overall performance of the anode material. If the proportion of proton solvent is too low, it will reduce the solubility of the mixed solvent in the solid electrolyte, leading to insufficient electrolyte dissolution, affecting the particle size uniformity of the electrolyte particles, and thus controlling the pore volume ratio of the solid electrolyte particles. When the proton solvent and non-proton solvent are mixed in the reasonable proportion specified in this invention, the electrolyte dissolution and precipitation processes can be synergistically optimized, successfully preparing the anode material described in this invention and effectively improving the cycle performance and fast charging performance of the all-solid-state battery.

[0120] Examples 12-15, while maintaining identical preparation conditions, employed different types of high-entropy sulfide solid electrolytes. Test results showed that as long as the percentage of solid electrolyte particles in the pore volume of the porous silicon-carbon material (pore volume ratio) is controlled within a suitable range, all-solid-state batteries with excellent cycle performance and fast-charging performance can be prepared. In contrast, Comparative Example 2 used a traditional sulfide solid electrolyte instead of the high-entropy sulfide solid electrolyte described in this invention. The resulting all-solid-state battery exhibited significantly poorer cycle performance and fast-charging performance. The core reason for these performance differences lies in the low ionic conductivity of traditional non-high-entropy sulfide solid electrolytes, making it difficult to construct efficient Li-Cell alloys within the nanopores of porous silicon-carbon materials. + The lack of a transmission network leads to low lithium-ion transport efficiency. Furthermore, its poor chemical and electrochemical stability makes it prone to interfacial side reactions with silicon or lithium during battery cycling, generating inert products and causing a continuous increase in interfacial impedance. In addition, the mechanical properties of traditional sulfide solid electrolytes are brittle and hard, unable to adapt to the dramatic volume expansion of silicon during lithiation / delithiation, resulting in interfacial contact failure and disrupting ion transport pathways. Moreover, its poor dispersibility in mixed solvents makes it difficult to uniformly fill the pore structure of porous silicon-carbon materials, easily forming ion transport "dead zones" and further degrading battery performance. Additionally, its weak thermal and air stability increases the difficulty of battery fabrication, storage, and practical application. In contrast, the high-entropy sulfide solid electrolyte used in this invention, relying on the "cocktail effect" and high configurational entropy generated by the synergistic effect of multiple elements, not only significantly improves its own ionic conductivity, interface stability and mechanical flexibility, but also effectively buffers the volume change of silicon during cycling. At the same time, it achieves nanoscale uniform composite with porous silicon-carbon materials, thereby systematically solving the key technical bottleneck of silicon-based anodes in all-solid-state battery applications and ensuring the excellent comprehensive electrochemical performance of the battery.

[0121] Examples 3 and 16-18, while maintaining identical preparation conditions, employed different types of protic or non-protic solvents in experiments. The results showed that as long as the percentage of solid electrolyte particles in the porous silicon-carbon material's pore volume (pore volume ratio) is controlled within a reasonable range, all-solid-state batteries with excellent cycle performance and fast-charging performance can be prepared. Specifically, when using a mixed solvent of ethanol and acetonitrile in a 1:9 mass ratio, the prepared negative electrode material, when applied to an all-solid-state battery, achieves superior cycle performance. The core reason for this is that ethanol possesses the dual characteristics of both a hydrogen bond donor and acceptor, while acetonitrile primarily functions as a hydrogen bond acceptor. This combination better matches the hydrogen bonding requirements of different solutes in the system, effectively improving the solubility and dissolution reaction efficiency of the high-entropy sulfide solid electrolyte, laying the foundation for subsequent uniform electrolyte precipitation and precise control of the pore volume ratio. Compared to this combination, other solvent combinations are significantly less compatible in terms of hydrogen bonding: for example, methanol's hydrogen bond donor capacity is too strong, easily leading to excessive solvation of the electrolyte and affecting subsequent precipitation; carbon tetrachloride and toluene lack hydrogen bonding capabilities, making it difficult to effectively break the electrolyte lattice and promote its dissolution. Furthermore, ethanol and acetonitrile both have moderate boiling points, making them easily removed through evaporation after the electrolyte is fully dissolved, thereby inducing the orderly precipitation of electrolyte particles and further ensuring the structural integrity and performance stability of the anode material.

[0122] The silicon-carbon composite anode material provided by this invention uses porous silicon-carbon material as a matrix, and precisely anchors a high-entropy sulfide solid electrolyte at the nanoscale within the internal channels and surface of the porous silicon-carbon material matrix, successfully constructing a multifunctional synergistic system integrating "silicon active center—carbon conductive network—high-entropy sulfide ion channel". This synergistic system can achieve synergistic optimization of efficient utilization of active materials, smooth electron transport, and efficient ion transport, effectively solving the technical problems of high interface impedance, poor ion transport, and easy debonding due to volume expansion in existing silicon-based anodes in all-solid-state batteries, significantly improving the cycle life, rate performance, and fast-charging performance of all-solid-state batteries. Therefore, this invention effectively overcomes some practical problems in the prior art and has high utilization value and application significance.

[0123] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A negative electrode material, characterized in that, include: Porous silicon-carbon materials; High-entropy sulfide solid electrolyte is distributed on the surface and in the pores of the porous silicon-carbon material; The general chemical formula of the high-entropy sulfide solid electrolyte is: Li 4±x-y A y (M1 a M2 b M3 c S4 δ X δ In the formula, 0≤x≤1.5, 0≤y≤1.5; 0.4≤a≤0.8, 0.1≤b≤0.4, 0.1≤c≤0.3, a+b+c=1, 0≤δ≤1; A is selected from one or two of Na and K; M1 is selected from one or more of Ge, Sn, Si, P, As, and B; M2 is selected from one or more of Sb, Nb, Ta, V, Mo, W, Ti, Zr, Hf, and Re; M3 is selected from one or more of Al, Ga, In, Bi, Pb, Mg, Ca, Zn, Cd, Y, Sc, La, Ba, Sr, Ce, and Sm; X is selected from one or more of O, Se, and Te.

2. The negative electrode material according to claim 1, characterized in that, In the negative electrode material, the volume of the high-entropy sulfide solid electrolyte accounts for 9% to 95% of the pore volume of the porous silicon-carbon material; the mass ratio of the porous silicon-carbon material to the high-entropy sulfide solid electrolyte is (1 to 100):

1.

3. The negative electrode material according to claim 1, characterized in that, The high-entropy sulfide solid electrolyte has a D50 of 1 nm to 500 nm.

4. The negative electrode material according to claim 1, characterized in that, The mass of silicon particles in the negative electrode material accounts for 30% to 80% of the total mass of the negative electrode material.

5. The negative electrode material according to claim 1, characterized in that, The pore volume of the negative electrode material is 0.01 cm³. 3 / g~1cm 3 / g; the average pore size of the negative electrode material is 1nm~2μm, and the specific surface area is 1m². 2 / g~800m 2 / g.

6. The negative electrode material according to claim 1, characterized in that, The porous silicon-carbon material has a D50 of 1μm to 30μm, an average pore size of 2nm to 4μm, and a specific surface area of ​​10m². 2 / g~1000m 2 / g, pore volume 0.1m 3 / g~1.2m 3 / g; the porous silicon-carbon material has a micropore ratio of 1%~10%, a mesopore ratio of 40%~60%, and a macropore ratio of 20%~50%.

7. A method for preparing the negative electrode material according to any one of claims 1 to 6, characterized in that, Includes the following steps: A mixed solvent is prepared by mixing protic solvent and non-protic solvent in a certain proportion; A high-entropy sulfide solid electrolyte is dispersed in the mixed solvent to prepare a mixed solution; A porous silicon carbon material is added to the mixed solution and dispersed evenly to obtain a slurry; The solvent in the slurry is removed to obtain the negative electrode material; The mass ratio of the protic solvent to the aprotic solvent is 1:(1~10).

8. The method for preparing the negative electrode material according to claim 7, characterized in that, The proton solvent includes one or more of ethanol, methanol, 1,2-ethylenediamine, and 1,2-ethylenedithiol; The aprotic solvent includes one or more of toluene, xylene, benzene, acetonitrile, diethyl ether, and carbon tetrachloride; The mass ratio of the high-entropy sulfide solid electrolyte to the mixed solvent is 1:(50~200).

9. An all-solid-state battery, characterized in that, The all-solid-state battery includes a positive electrode, a solid electrolyte layer, and a negative electrode. The negative electrode includes the negative electrode material according to any one of claims 1 to 6, or the negative electrode material prepared by the preparation method according to claim 7 or 8.

10. An electrical appliance, characterized in that, Including the all-solid-state battery as described in claim 9.

Images