A lithium-sulfur silver-germanium mineral-based multiphase solid electrolyte material, its preparation method and application

Abstract

This invention provides a lithium-sulfur silver-germanium ore-based multiphase solid-state electrolyte material, its preparation method, and its application, relating to the field of solid-state battery technology. The multiphase solid-state electrolyte material comprises a metal / oxygen co-doped lithium-sulfur silver-germanium ore phase as a matrix, with heterogeneous disulfide nanoparticles dispersed at the grain boundaries of this matrix. This invention utilizes a lithium-sulfur silver-germanium ore-type solid-state electrolyte with high ionic conductivity as the matrix material and introduces high-valence metals and oxygen elements for co-doping, promoting the formation of sulfur vacancies and reducing the lithium-ion diffusion barrier. Simultaneously, the interfacial effect of the heterogeneous disulfide nanoparticles at the grain boundaries helps reduce the internal interfacial resistance of the electrolyte, further improving lithium-ion conduction efficiency. Furthermore, the high electronegativity of the high-valence metals and oxygen elements, along with the in-situ passivation effect of the heterogeneous disulfide, significantly enhances the stability of the electrolyte under high-voltage conditions, reduces side reactions between the electrolyte and the cathode material, and improves the overall cycle performance of the battery.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery technology, and in particular to a lithium-sulfur silver-germanium mineral-based multiphase solid electrolyte material, its preparation method, and its application. Background Technology

[0002] All-solid-state batteries fundamentally solve the risk of thermal runaway by completely replacing the flammable organic electrolyte in traditional lithium-ion batteries with a solid electrolyte. Their thermal runaway trigger temperature is increased from approximately 150°C in traditional batteries to over 400°C. Furthermore, all-solid-state batteries have a theoretical energy density of 500-700 Wh / kg, more than 1.5 times that of the current mainstream 300 Wh / kg system, and possess an ultra-wide operating temperature range (-40 to 150°C), meeting the needs of extreme applications such as electric vehicles and aerospace. However, the industrialization of all-solid-state batteries has long been limited by the performance bottleneck of solid electrolyte materials—they must simultaneously meet the requirements of high ionic conductivity (>10 mS / cm) and a wide electrochemical window (>4.5 V vs. Li). + / Li), low interface impedance (<50 Ω·cm) 2 The seemingly contradictory technical indicators of high mechanical strength (>1 GPa) and low-cost manufacturing constitute the so-called "performance impossible triangle".

[0003] Currently, mainstream solid-state electrolyte materials can be divided into three categories: 1. Oxide type (such as Garnet type Li7La3Zr2O) 12 NASICON-type LiTi2(PO4)3: exhibits excellent chemical stability (>5 V), but its room-temperature ionic conductivity is low (approximately 10 V). - 4 S / cm), and high interfacial impedance (>1000 Ω·cm). 2 1. High-temperature sintering (>1200℃) is required for densification, resulting in high manufacturing costs; 2. Polymer-based (e.g., PEO-based, PVDF-based): These have good processing properties, but their room temperature ionic conductivity is below 10. - 4 S / cm, poor oxidation resistance (<3.8 V), making it difficult to match high-voltage cathode materials; 3. Sulfide type (such as Thio-LISICON, sulfide-germanium ore): with excellent intrinsic ionic conductivity (10 S / cm, poor oxidation resistance (<3.8 V), it is ...4. Sulfide type (such as Thio-LISICON, sulfide-germanium ore): with excellent intrinsic ionic conductivity (10 S / cm, poor oxidation resistance (<3.8 V), it is difficult to match high-voltage cathode materials; 5. Sulfide type (such as Thio-LISICON, sulfide-germanium ore): with excellent intrinsic ionic conductivity (10 S / cm, poor oxidation resistance (<3. -3 -10 -2 S / cm), good interfacial flexibility (interfacial resistance of cold-pressed molding <10 Ω·cm) 2With its moderate manufacturing cost, it has become the most promising type of solid-state electrolyte for industrialization. Among them, lithium-sulfur silver-germanium mineral electrolytes (such as Li6PS5X, X=Cl, Br, I) have attracted much attention due to their unique crystal structure advantages: their face-centered cubic lattice (space group F-43m) consists of [PS4]... 3- The three-dimensional lithium-ion diffusion channel constructed with tetrahedrons can theoretically achieve a migration activation energy as low as 0.18 eV.

[0004] Despite the promising application prospects of sulfide-germanium ore-based electrolytes, their practical application still faces two major challenges: 1. Insufficient intrinsic ionic conductivity: Limited by sulfur vacancy concentration and interfacial impedance dominated by grain boundaries, the room temperature conductivity of commercial-grade Li6PS5Cl is typically between 2-8 mS / cm. According to statistical analysis of research literature from the past three years (Nat. Rev. Mater., 2024, 9, 887-905), only a few samples have conductivity exceeding 10 mS / cm. Considering the performance loss during solid-state electrolyte film formation, the ionic conductivity of sulfides is still below the threshold required for industrial applications, resulting in poor battery rate performance (1C discharge capacity retention <80%); 2. Poor oxidation stability: Under high voltage conditions (>3.8 V vs. Li... + (Li), sulfides are prone to irreversible oxidative decomposition, triggering chain side reactions, leading to a significant increase in interfacial impedance, structural damage, and battery capacity decay.

[0005] To overcome the aforementioned technical bottlenecks, the industry mainly adopts two types of modification strategies, but both have certain limitations: one is structural doping, which mainly involves introducing anions with high electronegativity (such as O). 2- F - ) and specific metal cations (such as Cu) 2+ Al 3+ Sn 4+ Sb 5+ 、Nb 5+ Mo 6+1) Modifying the matrix. For example, the published Chinese invention patent CN 117430141 A introduces Zn and O elements into a sulfide electrolyte of sulfide type, improving its air stability while maintaining high ionic conductivity. The authorized Chinese invention patent CN 114744287 B successfully prepared a niobium-doped sulfide solid electrolyte with high ionic conductivity and excellent capacity performance by substituting Nb elements at P sites and controlling the doping ratio of niobium elements. The authorized Chinese invention patent CN 114883642 B achieves excellent ionic conductivity and good electrochemical stability in sulfide electrolyte of sulfide type by introducing high-valence metal Mo. 2) Surface coating treatment. Commonly used coating materials include polymer semiconductor g-C3N4, metal oxides (such as ZnO, Al2O3, Li2CO3), and lithium-ion conductor nanomaterials (such as Li). 6.5 La3Zr 1.5 Ta 0.5 O 12 ) and surface treatment agents such as Lewis acid or trithiocyanate.

[0006] While the aforementioned literature and patents have achieved some success in improving the ionic conductivity and electrochemical performance of sulfide solid electrolytes, current modification strategies for silver-germanium sulfide electrolytes still face a dilemma of "addressing one problem while leaving two others unresolved": bulk doping can improve conductivity, but the effect is limited; surface coating can enhance interfacial stability, but may hinder ion transport; and neither of these can solve the fundamental problem of synergistic decay of the bulk phase and interface under high voltage. Therefore, it is urgent to develop a novel electrolyte structure that combines high bulk conductivity, high interfacial stability, and excellent high-voltage withstand capability through innovation in material design principles, in order to overcome the final barrier to the industrialization of all-solid-state batteries. Summary of the Invention

[0007] To address the aforementioned problems in the prior art, this invention provides a lithium-sulfur silver-germanium ore-based multiphase solid electrolyte material, its preparation method, and its application, thereby achieving a lithium-sulfur silver-germanium ore-type solid electrolyte material with high ionic conductivity and high electrochemical stability.

[0008] One of the objectives of this invention is to provide a lithium-sulfur-silver-germanium mineral-based multiphase solid electrolyte material.

[0009] The second objective of this invention is to provide a method for preparing the lithium-sulfur silver-germanium mineral-based multiphase solid electrolyte material.

[0010] The third objective of this invention is to provide an application of the lithium-sulfur silver-germanium mineral-based multiphase solid electrolyte material.

[0011] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0012] In a first aspect, the present invention provides a lithium-sulfur-silver-germanium mineral-based multiphase solid electrolyte material, comprising:

[0013] Metal / oxygen co-doped lithium-sulfur-silver-germanium mineral phase matrix, and,

[0014] Heterogeneous disulfide nanoparticles dispersed at the grain boundaries of the matrix.

[0015] The chemical formula of the metal / oxygen co-doped lithium-sulfur-silver-germanium mineral phase matrix is ​​as follows: Chemical Formula I or Chemical Formula II:

[0016] Chemical formula I: Li 6-a P 1-b M b S 5-c O c Cl 1+d Where: M is selected from at least one of W and Mo; 0 ≤ a ≤ 0.5, 0 <b≤0.05,0<c≤0.3,0≤d<0.5;

[0017] Chemical Formula II: Li 5.5+a P 1-b M b S 4.5-c O c Cl 1.5-d+e Br d Where: M is selected from at least one of W and Mo; 0 ≤ a ≤ 0.5, 0 <b≤0.05,0<c≤0.3,0≤d<1.5,0<e≤0.3。

[0018] The lithium-sulfur silver-germanium ore-based multiphase solid electrolyte material provided by this invention effectively regulates the sulfur vacancy concentration by introducing high-valence metal cations and oxygen anions into the lithium-sulfur silver-germanium ore lattice, thereby reducing the lithium-ion diffusion barrier and improving lithium-ion conductivity. Compared with sulfide solid electrolytes treated by other modification methods, this material exhibits higher ionic conductivity. Furthermore, due to the introduction of highly electronegative high-valence metal cations and oxygen anions, [PS4] 3- The tetrahedral structure enhances stability, thereby improving the electrolyte's oxidation resistance under high voltage conditions and further enhancing the capacity and cycle life of the all-solid-state battery. Simultaneously, the heterogeneous disulfide nanoparticles distributed at the main phase grain boundaries not only help regulate lithium-ion conductivity at the grain boundaries but also generate an in-situ passivation effect under high voltage conditions, further enhancing lithium-ion transport capability and the material's voltage stability. This invention significantly improves the electrochemical stability of solid-state batteries by regulating and stabilizing the structure of traditional sulfide solid electrolytes, thus obtaining a high-performance solid electrolyte material with promising commercial applications.

[0019] Preferably, the metal includes one or more of tungsten and molybdenum.

[0020] Preferably, the lithium-sulfur-silver-germanium mineral phase includes a conventional Li-PS-Cl halogen system, a Li-PS-Cl halogen-rich system, and a Li-PS-Cl-Br system. More preferably, it includes Li6PS5Cl and Li... 5.5 PS 4.5 Cl 1.5 Li 5.5 PS 4.5 Cl 0.8 Br 0.7 One or more of them. More preferably, it includes Li. 5.5 PS 4.5 Cl 1.5 and Li 5.5 PS 4.5 Cl 0.8 Br 0.7 One or more of them.

[0021] Preferably, the heterophase disulfide nanoparticles include one or more of tungsten disulfide (WS2) and molybdenum disulfide (MoS2).

[0022] More preferably, the heterophase disulfide nanoparticles include WS2.

[0023] Preferably, based on the primary particle size of the lithium-sulfur-silver-germanium mineral-based multiphase solid electrolyte material, the primary particle size ratio of the heterogeneous disulfide nanoparticles is less than or equal to 20%, for example, it can be 1%, 2%, 5%, 6%, 8%, 10%, 15%, or 20%, etc.

[0024] Preferably, the particle size of the heterophase disulfide nanoparticles is 5~200 nm, for example, it can be 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm or 200 nm.

[0025] Secondly, the present invention provides a method for preparing the above-mentioned lithium-sulfur silver-germanium mineral-based multiphase solid electrolyte material, comprising the following steps:

[0026] Raw materials containing tungsten oxychloride and / or molybdenum oxychloride are introduced as additives into the raw materials for the synthesis of lithium sulfide silver germanium ore-type solid electrolytes. After uniform mixing and tableting, lithium sulfide silver germanium ore-based multiphase solid electrolyte materials are synthesized by high-temperature solid-state method.

[0027] The raw materials for synthesizing the lithium-sulfur silver-germanium ore type solid electrolyte include one or more of Li2S, P2S5, LiBr and LiCl; the raw materials containing tungsten oxychloride and / or molybdenum oxychloride include one or more of WO2Cl2, WOCl4, MoO2Cl2 and MoOCl4.

[0028] Preferably, based on the mass of the lithium-sulfur silver-germanium ore-type solid electrolyte formed from the raw materials, the amount of raw materials containing tungsten oxychloride and / or molybdenum oxychloride added is 0.5wt% to 10wt%, more preferably 0.5wt% to 3wt%, for example, it can be 0.5wt%, 1wt%, 2wt% or 3wt%; and even more preferably 1wt%.

[0029] In this invention, when the raw materials for synthesizing lithium-sulfur silver-germanium ore-type solid electrolytes are mixed with raw materials containing tungsten oxychloride and / or molybdenum oxychloride, dry mixing or wet mixing can be used; preferably, dry mixing is used.

[0030] The mixing method may include manual mixing, pulverizer mixing, mechanical fusion mixing, or planetary ball milling mixing; preferably, planetary ball milling mixing.

[0031] Preferably, the artificial mixing time is 5 to 60 minutes;

[0032] Preferably, the mixing speed of the grinder is 10,000 to 50,000 rpm; more preferably, the speed is 30,000 rpm. The mixing time is 1 to 20 minutes; more preferably, the mixing time is 2 minutes.

[0033] Preferably, the linear velocity of the mechanical fusion is 5~40 m / s and the fusion time is 2~10 min; more preferably, the linear velocity of the mechanical fusion is 10 m / s and the fusion time is 5 min.

[0034] Preferably, the planetary ball milling speed is 200-800 rpm and the mixing time is 2 min-10 h; more preferably, the planetary ball milling speed is 550 rpm and the mixing time is 30 min. More preferably, the ball-to-material ratio in the planetary ball milling is 20-50:1; even more preferably, the ball-to-material ratio is 40:1.

[0035] Preferably, the tableting pressure is 100-800 MPa; more preferably, the tableting pressure is 300 MPa. The tablets after tableting have a diameter of 5-50 mm and a thickness of 1-10 mm; preferably, the tablets have a diameter of 10 mm and a thickness of 2 mm.

[0036] Preferably, the heat treatment temperature for the high-temperature solid-state synthesis is 100~600 ℃, and the holding time is 2~50 h; more preferably, the heat treatment temperature is 450 ℃, and the holding time is 12 h. The heating rate is 1~5 ℃ / min; more preferably, the heating rate is 2 ℃ / min. After heat treatment, cooling is performed at a rate of 1~10 ℃ / min; more preferably, the cooling rate is 5 ℃ / min.

[0037] Preferably, the atmosphere used for the high-temperature solid-state synthesis is a vacuum or an inert gas atmosphere; more preferably, the atmosphere is an inert gas atmosphere.

[0038] The method for preparing lithium-sulfur-silver-germanium mineral-based multiphase solid electrolyte materials provided by the present invention employs in-situ dry mixing and heat treatment technology. Compared with existing coating technologies, this method is simpler, more efficient, and reduces energy consumption.

[0039] Thirdly, the present invention provides the application of the above-mentioned lithium-sulfur silver-germanium mineral-based multiphase solid electrolyte material in the preparation of all-solid-state lithium batteries.

[0040] In this invention, the all-solid-state lithium battery is an all-solid-state lithium secondary battery. The all-solid-state lithium battery prepared using the above-mentioned lithium-sulfur-silver-germanium mineral-based multiphase solid electrolyte material exhibits low battery impedance and high electrochemical stability.

[0041] Beneficial effects:

[0042] This invention provides a lithium-sulfur silver-germanium ore-based multiphase solid-state electrolyte material, its preparation method, and its applications. This method utilizes a lithium-sulfur silver-germanium ore-type solid-state electrolyte with high ionic conductivity as the matrix, introducing high-valence metal ions and oxygen ions with high electronegativity into its bulk structure, and introducing heterogeneous disulfide nanoparticles at grain boundaries. This modulates sulfur vacancies and grain boundary conduction behavior, reduces the lithium-ion diffusion barrier, and thus improves the lithium-ion conduction efficiency in the electrolyte. Furthermore, the synergistic effect of these two regulatory mechanisms also helps enhance the structural stability of the electrolyte and effectively suppresses side reactions between the cathode material and the electrolyte, thereby significantly improving the stability and cycle performance of solid-state batteries under high-voltage conditions.

[0043] Furthermore, the method described in this invention is applicable to various inorganic solid electrolytes with good ionic conductivity, such as halide-type solid electrolytes. The process is simple, the raw materials are widely available, and the cost is low, demonstrating good potential for industrial application. In addition, this method has high production efficiency, is suitable for large-scale industrial production, and has broad commercial application prospects, possessing both significant theoretical value and practical application significance.

[0044] The present invention has been described in detail above; however, the above embodiments are merely illustrative in nature and are not intended to limit the invention. Furthermore, this document is not limited to the foregoing prior art or the invention itself, or to any theory described in the following embodiments. Attached Figure Description

[0045] Figure 1 SEM and TEM images of the solid electrolyte material of Example 1 provided by the present invention.

[0046] Figure 2 XRD patterns of solid electrolyte materials of Examples 1-3 and Comparative Example 1 provided by the present invention.

[0047] Figure 3 Raman diagrams of the solid electrolyte materials of Examples 1-3 and Comparative Example 1 provided by the present invention.

[0048] Figure 4 Cyclic performance diagram of the solid electrolyte material of Example 1 provided by the present invention.

[0049] Figure 5 SEM image of the solid electrolyte material of Example 4 provided by the present invention.

[0050] Figure 6 XRD patterns of solid electrolyte materials of Examples 4-6 and Comparative Example 2 provided by the present invention.

[0051] Figure 7 Cyclic performance diagram of the solid electrolyte material of Example 4 provided by the present invention.

[0052] Figure 8 TEM images of the solid electrolyte materials of Comparative Examples 4-5 provided by this invention.

[0053] Figure 9 SEM image of the solid electrolyte material of Comparative Example 1 provided by the present invention.

[0054] Figure 10 Cyclic performance diagram of the solid electrolyte material of Comparative Example 1 provided by the present invention.

[0055] Figure 11 SEM image of the solid electrolyte material of Comparative Example 2 provided by the present invention.

[0056] Figure 12 Cyclic performance diagram of solid electrolyte material in Comparative Example 2 provided by the present invention. Detailed Implementation

[0057] The present invention will be further described below with reference to the embodiments. It should be noted that the following embodiments are provided for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0058] Unless otherwise specified, the raw materials, reagents, and methods used in the embodiments are all conventional raw materials, reagents, and methods in the art.

[0059] Example 1

[0060] This embodiment provides a lithium-sulfur silver-germanium mineral-type multiphase solid electrolyte material with W / O co-doping and WS2 heterophase. The specific steps of the preparation method of this material are as follows:

[0061] Accurately weigh 0.2278 g LiCl, 0.4083 g LiBr, 0.6173 g Li₂S, 0.7465 g P₂S₅, and 0.02 g WO₂Cl₂ raw materials and place them in a 50 mL ball mill jar. Add Φ5 mm ZrO₂ grinding balls at a ball-to-material mass ratio of 40:1. The grinding process is carried out in a planetary high-energy ball mill using dry ball milling without the addition of any solvent. The ball milling program consists of two stages: first, pre-milling at a low speed of 120 rpm for a total time of 2 minutes to achieve uniform mixing of the raw materials; then, ball milling continues at a high speed of 550 rpm for a total time of 30 minutes. After ball milling, sulfide precursors are obtained. Two g of the precursor was placed in a tableting mold and compressed at a pressure of 300 MPa. The resulting tablets had a diameter of 10 mm and a thickness of 2 mm. The resulting tablets were then placed in a muffle furnace and calcined under an inert atmosphere at 450 °C for 12 hours. After calcination, the resulting electrolyte material was ground into powder using an agate mortar and pestle and stored in a sealed container for later use. The obtained multiphase solid electrolyte is abbreviated as LPLSOCB@WS2-1.

[0062] Figure 1 The images show scanning electron microscope (SEM) images (top) and transmission electron microscope (TEM) images (bottom) of the multiphase solid electrolyte prepared in Example 1. The SEM images show that the primary particle size of the multiphase electrolyte is approximately 500 nm. In addition, lattice fringes of the sulfogermanium ore-type electrolyte phase and the WS2 phase can be observed in the TEM images, indicating the presence of a second phase WS2 in the electrolyte, with an average particle size of approximately 10 nm, dispersed in the sulfogermanium ore phase electrolyte matrix.

[0063] Figure 2The image shows the X-ray diffraction (XRD) structure of the multiphase solid electrolyte. The figure displays the characteristic diffraction peaks of the sulfide-germanium sulfide-type Li7PS6 electrolyte, indicating that the prepared sulfide solid electrolyte has a cubic crystal structure belonging to space group F-43m (space group number 216). Furthermore, characteristic diffraction peaks of the WS2 phase can also be observed in the figure, indicating the presence of a second phase, WS2, in the electrolyte.

[0064] Figure 3 This is the Raman spectrum of the multiphase solid electrolyte. The spectrum is located at approximately 550-600 cm⁻¹. -1 The presence of stretching vibration peaks in the PS bond within the range indicates that its structural framework is [PS3Cl]. 3- Tetrahedron; in addition, at approximately 410-430 cm -1 Characteristic Raman peaks of the WS2 phase were detected within the range, further confirming the coexistence of the main phase of silver-germanium sulfide and the second phase WS2 in this multiphase electrolyte.

[0065] The following performance tests were performed on the multiphase solid electrolyte prepared in this embodiment:

[0066] (1) Ionic conductivity test: 100 mg of electrolyte powder was accurately weighed and placed in a specially made solid-state battery mold, and pressed into a sheet sample under a pressure of 300 MPa. Subsequently, electrochemical impedance spectroscopy was used to test the electrochemical impedance, and the ionic conductivity of the multiphase solid electrolyte was calculated using the Arrhenius equation. The test results are listed in Table 1. It can be seen that the lithium-ion conductivity of the LPLSOCB@WS2-1 multiphase solid electrolyte prepared in this embodiment is as high as 13 mS / cm, indicating that the W / O co-doped and WS2 heterophase lithium-sulfur-silver-germanium mineral-type multiphase solid electrolyte material prepared by adding WO2Cl2 raw material has higher ionic conductivity.

[0067] (2) Electrochemical stability and cycle performance test: 100 mg of the multiphase solid electrolyte powder obtained in Example 1 was pressed into shape under a pressure of 300 MPa. Then, the electrolyte powder was mixed with LiNi 0.83 Co 0.15 Mn 0.02 O2 (NCM83) cathode material was thoroughly mixed in an agate mortar at a mass ratio of 3:7 to obtain a composite cathode material. Approximately 8 mg of the composite cathode material was evenly spread on one side of the electrolyte sheet, and a carbon-coated aluminum foil was placed on top as the cathode current collector to isolate the cathode from the stainless steel pillar. Lithium metal foil was attached to the other side of the electrolyte sheet, and a copper foil was placed on its outer side as the negative cathode current collector, similarly isolated from the stainless steel pillar. A pressure of 50 MPa was then applied to the entire battery assembly to ensure tight contact between the layers. Constant current charge-discharge tests were conducted on the Blue Electric CT2001A battery testing system, with a test voltage range of 2.8-4.3 V (vs. Li / Li).+ The charge / discharge rate is 1 C. Figure 4 The image shows the cycle performance curves of the all-solid-state battery assembled based on the multiphase solid-state electrolyte prepared in Example 1. The test results show that after 100 charge-discharge cycles, the battery retains approximately 95.5% of its discharge capacity, and the discharge specific capacity reaches 154.6 mAh·g. -1 This indicates that the electrolyte material has good electrochemical cycling stability.

[0068] Example 2

[0069] This embodiment provides a lithium-sulfur silver-germanium mineral-type multiphase solid electrolyte material with W / O co-doping and WS2 heterophase. Its preparation method is the same as that in Example 1, except that the mass of WO2Cl2 raw material is increased to 0.04 g. The obtained multiphase solid electrolyte is referred to as LPLWSOCB@WS2-2.

[0070] The ionic conductivity of Example 2 is shown in Table 1. It can be seen that the lithium-ion conductivity of the LPLSOCB@WS2-2 multiphase solid electrolyte prepared in this example is as high as 12.8 mS / cm. The XRD pattern of Example 2 is shown in... Figure 2 The Raman spectrum of this embodiment is shown below. Figure 3 Similarly, it can be observed that the main phase of silver-germanium sulfide and the second phase WS2 coexist in this multiphase electrolyte, with the content of the second phase WS2 being higher than in Example 1.

[0071] Example 3

[0072] This embodiment provides a lithium-sulfur silver-germanium mineral-type multiphase solid electrolyte material with W / O co-doping and WS2 heterophase. The preparation method is the same as in Example 1, except that the mass of WO2Cl2 raw material is increased to 0.1 g, and the obtained multiphase solid electrolyte is referred to as LPLSOCB@WS2-3.

[0073] The ionic conductivity of Example 3 is shown in Table 1. It can be seen that the lithium-ion conductivity of the LPWSOCB@WS2-3 multiphase solid electrolyte prepared in this example is as high as 11.8 mS / cm. The XRD pattern of Example 3 is shown in Table 1. Figure 2 The Raman spectrum of this embodiment is shown below. Figure 3 Similarly, it can be observed that the main phase of silver-germanium sulfide and the second phase WS2 coexist in this multiphase electrolyte, with the content of the second phase WS2 being higher than that in Example 2.

[0074] Example 4

[0075] This embodiment provides a lithium-sulfur silver-germanium mineral-type multiphase solid electrolyte material with W / O co-doping and WS2 heterophase. The specific steps of the preparation method of this material are as follows:

[0076] Accurately weigh 0.477 g LiCl, 0.6894 g Li₂S, 0.8337 g P₂S₅, and 0.02 g WO₂Cl₂ raw materials and place them in a 50 mL ball mill jar. Add Φ5 mm ZrO₂ grinding balls at a ball-to-material mass ratio of 40:1. The grinding process is carried out in a planetary high-energy ball mill using dry ball milling without adding any solvent. The ball milling program consists of two stages: first, pre-milling at a low speed of 120 rpm for a total time of 2 minutes to achieve uniform mixing of the raw materials; then, ball milling continues at a high speed of 550 rpm for a total time of 30 minutes. After ball milling, sulfide precursors are obtained. Two g of the precursor was placed in a tableting mold and compressed at a pressure of 300 MPa. The resulting tablets had a diameter of 10 mm and a thickness of 2 mm. The resulting tablets were then placed in a muffle furnace and calcined under an inert atmosphere at 450 °C for 12 hours. After calcination, the resulting electrolyte material was ground into powder using an agate mortar and pestle and stored in a sealed container for later use. The obtained multiphase solid electrolyte is abbreviated as LPWSOC@WS2-1.

[0077] Figure 5 This is a SEM image of the LPWSOC@WS2-1 multiphase solid electrolyte prepared in Example 4. The image shows that the primary particle size of this multiphase electrolyte is approximately 1 μm.

[0078] Figure 6 The image shows the XRD pattern of this multiphase solid electrolyte. The figure displays the characteristic diffraction peaks of the sulfide-germanium sulfide-type Li7PS6 electrolyte, indicating that the prepared sulfide solid electrolyte has a cubic crystal structure belonging to space group F-43m (space group number 216). Furthermore, characteristic diffraction peaks of the WS2 phase can also be observed in the figure, indicating the presence of a second phase, WS2, in the electrolyte.

[0079] The lithium-sulfur silver-germanium ore-type multiphase solid electrolyte material prepared in this embodiment was subjected to the same ionic conductivity tests as in Examples 1-3. The ionic conductivity of this embodiment is shown in Table 1. It can be seen that the lithium-ion conductivity of the LPWSOC@WS2-1 multiphase solid electrolyte prepared in this embodiment is as high as 8.9 mS / cm. The lithium-sulfur silver-germanium ore-type multiphase solid electrolyte material prepared in this embodiment was assembled into an all-solid-state battery in the same manner as in Example 1. Its 1C cycle performance curve is shown in Table 1. Figure 7 Test results show that after 300 charge-discharge cycles, the battery retains approximately 87% of its discharge capacity, with a discharge specific capacity reaching 130 mAh·g. -1 This indicates that the electrolyte material has good electrochemical cycling stability.

[0080] Example 5

[0081] This embodiment provides a lithium-sulfur silver-germanium mineral-type multiphase solid electrolyte material with W / O co-doping and WS2 heterophase. Its preparation method is the same as that in Example 4, except that the mass of WO2Cl2 raw material added is 0.04 g. The obtained multiphase solid electrolyte is referred to as LPWSOC@WS2-2.

[0082] The lithium-sulfur silver-germanium ore-type multiphase solid electrolyte material prepared in this embodiment was subjected to the same ionic conductivity and structural tests as in Examples 1-4. The ionic conductivity of this embodiment is shown in Table 1. It can be seen that the lithium-ion conductivity of the LPWSOC@WS2-2 multiphase solid electrolyte prepared in this embodiment is as high as 8.6 mS / cm. The XRD pattern of this embodiment is shown in... Figure 6 Similarly, it can be observed that the main phase of silver-germanium sulfide and the second phase WS2 coexist in this multiphase electrolyte, with the content of the second phase WS2 being higher than that in Example 4.

[0083] Example 6

[0084] This embodiment provides a lithium-sulfur silver-germanium mineral-type multiphase solid electrolyte material with W / O co-doping and WS2 heterophase. Its preparation method is the same as that in Example 4, except that the mass of WO2Cl2 raw material is increased to 0.1 g, and the obtained multiphase solid electrolyte is referred to as LPWSOC@WS2-3.

[0085] The lithium-sulfur silver-germanium ore-type multiphase solid electrolyte material prepared in this embodiment was subjected to the same ionic conductivity and structural tests as in Examples 1-5. The ionic conductivity of this embodiment is shown in Table 1. It can be seen that the lithium-ion conductivity of the LPWSOC@WS2-3 multiphase solid electrolyte prepared in this embodiment is as high as 7.8 mS / cm. The XRD pattern of this embodiment is shown in... Figure 6 Similarly, it can be observed that the main phase of silver-germanium sulfide and the second phase WS2 coexist in this multiphase electrolyte, and the content of the second phase WS2 is higher than that in Example 5.

[0086] Example 7

[0087] This embodiment provides a lithium-sulfur silver-germanium mineral-type multiphase solid electrolyte material with Mo / O co-doping and MoS2 heterophase. The preparation method is the same as in Example 1, except that WO2Cl2 raw material is replaced with MoO2Cl2 raw material. The obtained multiphase solid electrolyte is referred to as LPMSOCB@MS2-1.

[0088] The lithium-sulfur silver-germanium mineral-type multiphase solid electrolyte material prepared in this embodiment was subjected to the same ionic conductivity tests as in Examples 1-6. The ionic conductivity of this embodiment is shown in Table 1. It can be seen that the lithium-ion conductivity of the LPMSOCB@MS2-1 multiphase solid electrolyte prepared in this embodiment is as high as 10.9 mS / cm.

[0089] Comparative Example 1

[0090] This comparative example provides a Li 5.5 PS 4.5 Cl 0.8 Br 0.7 The solid electrolyte material is prepared in the same way as in Example 1, except that WO2Cl2 is not added to the raw materials.

[0091] Comparative Example 2

[0092] This comparative example provides a Li 5.5 PS 4.5 Cl 1.5 The solid electrolyte material is prepared in the same way as in Example 4, except that WO2Cl2 is not added to the raw materials.

[0093] Comparative Example 3

[0094] This comparative example provides a WO3-mixed Li 5.5 PS 4.5 Cl 0.8 Br 0.7 The solid electrolyte material is prepared in the same way as in Example 1, except that the WO2Cl2 added to the raw materials is replaced with WO3, and the obtained solid electrolyte is referred to as LPWSOCB@WO3.

[0095] Comparative Example 4

[0096] This comparative example provides a WCl6 mixed Li 5.5 PS 4.5 Cl 0.8 Br 0.7 The solid electrolyte material is prepared in the same way as in Example 1, except that the WO2Cl2 added to the raw materials is replaced with WCl6, and the obtained solid electrolyte is referred to as LPWSOCB@WCl6.

[0097] Comparative Example 5

[0098] This comparative example provides a WS2 mixed Li 5.5 PS 4.5 Cl 0.8 Br 0.7The solid electrolyte material is prepared in the same way as in Example 1, except that the WO2Cl2 added to the raw materials is replaced with WS2, and the obtained solid electrolyte is referred to as LPWSOCB@WS2.

[0099] TEM images of Comparative Examples 4 and 5 are as follows Figure 8 As shown, the synthesis of the silver-germanium sulfide phase electrolyte can be observed, but no heterogeneous phase dispersed in the silver-germanium sulfide phase electrolyte was found. The ionic conductivity of Comparative Examples 1-5 is shown in Table 1. It can be seen that the ionic conductivity of Comparative Examples 1-5 is smaller, further proving that the co-doping of high-valence metals and oxygen and the introduction of a second phase have a better improvement effect.

[0100] Comparative Example 1: SEM morphology, XRD structure, and Raman spectrum are shown below. Figure 9 , Figure 2 and Figure 3 It exhibits a cubic crystal structure similar to that of silver-germanium sulfide. The charge-discharge cycle curves of the all-solid-state battery assembled in Comparative Example 1 are shown below. Figure 10 It can be observed that after 100 charge-discharge cycles, the discharge capacity retention is approximately 95.5%, but the discharge specific capacity is only 141.9 mAh g⁻¹. -1 The discharge capacity is lower than that of the battery assembled with a multiphase solid electrolyte in Example 1 under the same conditions. The SEM morphology and XRD structure diagram of Comparative Example 2 are shown below. Figure 11 and Figure 6 It exhibits a hexagonal close-packed trigonal crystal structure. The charge-discharge cycle curves of the all-solid-state battery assembled in Comparative Example 2 are shown below. Figure 12 It can be observed that after 300 charge-discharge cycles, the discharge capacity retention rate has decreased to approximately 84.7%, and the discharge specific capacity is only 125.1 mAh g⁻¹. -1 This indicates that its electrochemical stability is poor.

[0101] Table 1. Test results of ionic conductivity of electrolyte materials

[0102]

[0103] In summary, this invention prepares the lithium-sulfur silver-germanium ore-based multiphase solid electrolyte material by in-situ introducing high-valence chlorine oxychloride compounds (such as WO2Cl2) into the sulfide system through short-term mechanical ball milling and heat treatment. This method effectively regulates sulfur vacancies and grain boundary conduction behavior, reducing the lithium-ion transport barrier in the electrolyte by introducing highly electronegative high-valence metal and oxygen ions into the bulk structure and nanoscale heterogeneous disulfide nanoparticles (such as WS2) into the lithium-sulfur silver-germanium ore electrolyte matrix. Therefore, the modified multiphase solid electrolyte exhibits significantly higher lithium-ion conductivity at room temperature than the unmodified material. Furthermore, the synergistic effect of these two regulatory mechanisms also helps improve the structural stability of the electrolyte and effectively suppresses side reactions between the cathode material and the electrolyte. When matched with commercially available layered cathode materials, the modified solid electrolyte demonstrates excellent cycle stability, showing a significant improvement in cycle life compared to conventional unmodified solid electrolytes, indicating good potential for commercial application.

[0104] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and substance defined by the claims of the present invention; and such modifications or substitutions are still within the scope defined by the claims of the present invention.

Claims

1. A lithium-sulfur-silver-germanium mineral-based multiphase solid electrolyte material, characterized in that, include: Metal / oxygen co-doped lithium-sulfur-silver-germanium mineral phase matrix, and, Heterogeneous disulfide nanoparticles dispersed at the grain boundaries of the matrix; The chemical formula of the lithium-sulfur silver-germanium mineral phase matrix is ​​Li 5.5 PS 4.5 Cl 1.5 Or Li 5.5 PS 4.5 Cl 0.8 Br 0.7 The metals include tungsten or molybdenum; Disulfides include tungsten disulfide or molybdenum disulfide.

2. The lithium-sulfur-silver-germanium mineral-based multiphase solid electrolyte material according to claim 1, characterized in that, Based on the primary particle size of the lithium-sulfur-silver-germanium mineral-based multiphase solid electrolyte material, the primary particle size ratio of the heterogeneous disulfide nanoparticles is less than or equal to 20%.

3. The lithium-sulfur-silver-germanium mineral-based multiphase solid electrolyte material according to claim 1, characterized in that, The particle size of the heterogeneous disulfide nanoparticles is 5~200 nm.

4. A method for preparing a lithium-sulfur-silver-germanium mineral-based multiphase solid electrolyte material according to any one of claims 1-3, characterized in that, Includes the following steps: Raw materials containing tungsten oxychloride or molybdenum oxychloride are introduced as additives into the raw materials for the synthesis of lithium sulfide silver germanium mineral-type solid electrolytes. After uniform mixing and tableting, lithium sulfide silver germanium mineral-based multiphase solid electrolyte materials are synthesized by high-temperature solid-state method.

5. The preparation method according to claim 4, characterized in that, The raw materials for synthesizing the lithium-sulfur silver-germanium ore type solid electrolyte include one or more of Li2S, P2S5, LiBr and LiCl; the raw materials containing tungsten oxychloride or molybdenum oxychloride include one or more of WO2Cl2, WOCl4, MoO2Cl2 and MoOCl4. Based on the mass of the lithium-sulfur silver-germanium ore-type solid electrolyte formed from the raw materials, the amount of raw materials containing tungsten oxychloride or molybdenum oxychloride added is 0.5wt%~10wt%.

6. The preparation method according to claim 4, characterized in that, The mixing methods include manual mixing, pulverizer mixing, mechanical fusion mixing, or planetary ball milling mixing.

7. The preparation method according to claim 4, characterized in that, The heat treatment temperature for the high-temperature solid-state synthesis is 100~600℃, and the holding time is 2~50h.

8. The application of the lithium-sulfur silver-germanium mineral-based multiphase solid electrolyte material according to any one of claims 1-3 in the preparation of all-solid-state lithium batteries.

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