Sulfide solid electrolyte precursor, preparation method of sulfide solid electrolyte and sulfide solid electrolyte precursor

Abstract

The invention discloses a sulfide solid electrolyte precursor and a preparation method of the sulfide solid electrolyte, and the preparation method of the sulfide solid electrolyte precursor and the precursor comprises the following steps: mixing Li2S powder and LiCl powder to obtain Li2S-LiCl composite powder; the method comprises the following steps: preparing Li2S-LiCl composite powder, heating P2S5 powder to form P2S5 steam, and depositing the P2S5 steam on the particle surface of the Li2S-LiCl composite powder to obtain sulfide solid electrolyte precursor powder, the precursor has a core-shell structure, and the core-shell structure takes the Li2S-LiCl composite powder as a core and takes amorphous P2S5 coated on the particle surface of the Li2S-LiCl composite powder as a shell. By preparing the sulfide solid electrolyte precursor with the core-shell structure, the mixing uniformity of all the components on the microscopic level is improved, and then the uniform and stable sulfide solid electrolyte is prepared.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a sulfide solid electrolyte precursor and a method for preparing the sulfide solid electrolyte, and the sulfide solid electrolyte precursor. Background Technology

[0002] Solid-state batteries, due to their high safety and high energy density, have become the core development direction of next-generation energy storage technology, and have broad application prospects in new energy vehicles, portable electronic devices, and large-scale energy storage power stations. Sulfide solid electrolytes, with ionic conductivity reaching 10⁻⁶ at room temperature, are particularly advantageous. -2 -10 -3 With a strength of mS / cm and excellent mechanical ductility, it is considered a research hotspot for promoting the industrialization of all-solid-state batteries.

[0003] Currently, the conventional methods for preparing sulfide solid electrolytes are high-temperature solid-state sintering and mechanical ball milling. However, solid-state sintering suffers from problems such as uneven raw material mixing, low reaction efficiency, easy generation of impurities, and high energy consumption; mechanical ball milling is difficult to avoid contamination introduced by the grinding media, and the process repeatability is poor. More importantly, both methods rely on the macroscopic physical mixing of raw material powders, but the random contact characteristics of raw material particles easily lead to uncontrollable microstructure of the sulfide solid electrolyte precursor, making it impossible to achieve precise and uniform mixing at the microscopic level, which in turn results in poor batch stability of the composition, structure, and electrical properties of the final product.

[0004] Therefore, there is an urgent need to develop a new method for preparing sulfide solid electrolyte precursors to improve the mixing uniformity of raw materials at the microscopic level. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this application is to provide a sulfide solid electrolyte precursor and a method for preparing sulfide solid electrolyte. The sulfide solid electrolyte precursor can achieve a uniform mixing effect at the microscopic level of raw materials, thereby improving the compositional uniformity and structural stability of the sulfide solid electrolyte.

[0006] To achieve one, some, or all of the above objectives, or other objectives, the first aspect of this application provides a method for preparing a sulfide solid electrolyte precursor, the method comprising:

[0007] Li2S powder and LiCl powder are mixed to obtain Li2S-LiCl composite powder;

[0008] P2S5 powder is heated to form P2S5 vapor, and the P2S5 vapor is deposited on the particle surface of the Li2S-LiCl composite powder to obtain a sulfide solid electrolyte precursor powder. The precursor has a core-shell structure, with the Li2S-LiCl composite powder as the core and amorphous P2S5 coating the particle surface of the Li2S-LiCl composite powder as the shell.

[0009] Further, the step of mixing Li2S powder and LiCl powder to obtain Li2S-LiCl composite powder includes:

[0010] Weigh out Li2S powder and LiCl powder in a mass ratio of (1~5):1 and place them in a ball mill jar for ball milling and mixing. The ball milling speed is 100~300 rpm and the ball milling time is 2~6 hours.

[0011] Furthermore, the mass ratio of the P2S5 powder to the Li2S powder is (1~3):1.

[0012] Further, the step of heating the P2S5 powder to form P2S5 vapor and depositing the P2S5 vapor on the particle surface of the Li2S-LiCl composite powder to obtain the sulfide solid electrolyte precursor powder includes:

[0013] The Li2S-LiCl composite powder is spread evenly in an open first reaction vessel, and the first reaction vessel is placed in the first temperature zone of the reactor;

[0014] P2S5 powder is placed in an open second reaction vessel, and the second reaction vessel is placed in the second temperature zone of the reactor, with the first temperature zone and the second temperature zone connected by a gas channel;

[0015] An inert gas is introduced into the reactor to create an inert atmosphere inside the reactor.

[0016] The second temperature zone is heated, and the gas flow rate of the reactor is adjusted to a preset flow rate so that the temperature of the second temperature zone is in the range of 150~450℃, and the temperature of the first temperature zone is in the range of 100~250℃. The temperature of the second temperature zone is higher than that of the first temperature zone. The P2S5 powder is converted into vapor in the second temperature zone, flows to the first temperature zone, and condenses and deposits on the particle surface of the Li2S-LiCl composite powder in the first temperature zone to form an amorphous P2S5 coating layer.

[0017] After a preset deposition time, heating is stopped, and the reactor is cooled to room temperature under a continuous inert atmosphere. The product in the first reaction vessel is then collected, which is the sulfide solid electrolyte precursor powder.

[0018] Furthermore, during the heating of the second temperature zone, the heating rate of the second temperature zone is 2~10℃ / min.

[0019] Furthermore, during the cooling process of the reactor, the cooling rate is 1~5℃ / min.

[0020] Furthermore, the preset flow rate is 50~200 sccm.

[0021] Furthermore, the preset deposition time is 30~120 min.

[0022] Furthermore, the reactor is a tubular reactor.

[0023] Furthermore, the inert gas includes at least one of argon and nitrogen.

[0024] The second aspect of this application provides a sulfide solid electrolyte precursor, which is prepared by the above-described method for preparing sulfide solid electrolyte precursors. The precursor has a core-shell structure, with Li2S-LiCl composite powder as the core and amorphous P2S5 as the shell. The overall particle size of the precursor is 1~10μm and the shell thickness is 3~10nm.

[0025] A third aspect of this application provides a method for preparing a sulfide solid electrolyte, wherein the sulfide solid electrolyte precursor is prepared by the above-described method for preparing a sulfide solid electrolyte precursor, and the method for preparing the sulfide solid electrolyte includes:

[0026] The sulfide solid electrolyte precursor is placed in a sealed container and subjected to heat treatment under an inert atmosphere. The heat treatment temperature is 300~500℃ and the heat treatment duration is 2~10h to obtain the sulfide solid electrolyte.

[0027] The sulfide solid electrolyte precursor and its preparation method provided in this application, along with the sulfide solid electrolyte precursor, improve the mixing uniformity of components at the microscopic level by pre-preparing a core-shell structured sulfide solid electrolyte precursor. This forms a fixed and extremely short solid-phase reaction interface, ensuring a highly uniform reaction path for subsequent heat treatment, ultimately yielding a high-purity, high-performance sulfide solid electrolyte and significantly improving product consistency. Simultaneously, the core-shell structure pre-positions the reactants in nanoscale close contact, shortening the ion diffusion distance, lowering the reaction energy barrier, and significantly reducing the temperature and time required for subsequent synthesis, achieving energy-efficient and high-performance production. Furthermore, the shell layer preferentially reacts with trace amounts of water and oxygen in the environment, allowing the precursor to be processed in an industrial-grade drying chamber, reducing industrial production costs. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] in:

[0030] Figure 1 This is a TEM image of the sulfide solid electrolyte precursor prepared in Example 2;

[0031] Figure 2 The XRD patterns of the sulfide solid electrolytes prepared in Example 2 and Comparative Example 1 are shown.

[0032] Figure 3 The AC impedance spectra of the sulfide solid electrolytes prepared in Examples 1-6 are shown.

[0033] Figure 4 The AC impedance spectra of the sulfide solid electrolytes prepared in Comparative Examples 1-2 are shown. Detailed Implementation

[0034] 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 application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0035] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0036] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0037] This application provides a method for preparing a sulfide solid electrolyte precursor, the method comprising:

[0038] S1: Mix Li2S powder and LiCl powder to obtain Li2S-LiCl composite powder;

[0039] S2: Heat the P2S5 powder to form P2S5 vapor, and deposit the P2S5 vapor on the particle surface of the Li2S-LiCl composite powder to obtain a sulfide solid electrolyte precursor powder. The precursor has a core-shell structure, with the Li2S-LiCl composite powder as the core and the amorphous P2S5 coating the particle surface of the Li2S-LiCl composite powder as the shell.

[0040] In this embodiment, in step S1 above, Li2S powder and LiCl powder are weighed according to a preset ratio (selective mass ratio, molar ratio, etc.), and premixed by low-energy ball milling to obtain primary Li2S-LiCl composite powder. Premixing achieves uniform dispersion of Li2S and LiCl, forming uniform composite powder particles.

[0041] In step S2 above, P2S5 is directionally coated onto the surface of the Li2S-LiCl composite powder via vapor deposition, forming a core-shell structure. This achieves close contact and uniform dispersion of the components at the microscopic level, thereby improving the compositional uniformity and structural stability of the sulfide solid electrolyte. P2S5 serves as both a sulfur and phosphorus source, and will subsequently react with Li2S in the core layer to generate core electrolyte phases such as Li3PS4.

[0042] The sulfide solid electrolyte precursor prepared by the above steps in this application improves the mixing uniformity of each component at the microscopic level. It achieves uniform and complete coating of P2S5 on the core surface of the Li2S-LiCl composite powder at the atomic / molecular scale, forming a fixed and extremely short solid-phase reaction interface. This ensures a highly uniform reaction path for subsequent heat treatment, ultimately yielding a high-purity, high-performance sulfide solid electrolyte and significantly improving product consistency. Simultaneously, the core-shell structure pre-positions the reactants in close nanoscale contact, greatly shortening the ion diffusion distance and lowering the reaction energy barrier. This not only significantly reduces the temperature and time required for subsequent synthesis, achieving energy-efficient production, but also effectively avoids high-temperature side reactions. Furthermore, the shell layer preferentially reacts with trace amounts of water and oxygen in the environment, allowing the precursor to be processed in industrial-grade drying chambers (e.g., dew point -40°C), significantly reducing reliance on extremely anhydrous and oxygen-free environments such as glove boxes, and substantially lowering industrial production costs.

[0043] In some specific embodiments, step S1, which involves mixing Li₂S powder with LiCl powder to obtain Li₂S-LiCl composite powder, includes:

[0044] S101: Weigh out Li2S powder and LiCl powder in a mass ratio of (1~5):1 and place them into a ball mill jar for ball milling and mixing. The ball milling speed is 100~300 rpm and the ball milling time is 2~6 hours.

[0045] In this embodiment, the above-mentioned mass ratio is calculated based on the stoichiometric ratio of the sulfide solid electrolyte precursor to be prepared subsequently. Li₂S powder and LiCl powder are ball-milled and mixed under an inert atmosphere using a low-energy ball mill. Exemplarily, the ball milling speed can be 100 rpm, 150 rpm, 200 rpm, 250 rpm, 250 rpm, 300 rpm, etc.; the ball-to-material mass ratio is (10-50):(1-10), and exemplaryly, it can be 10:1, 10:5, 10:10, 20:1, 20:5, 20:10, 30:1, 30:5, 30:10, 40:1, 40:5, 40:10, 50:1, 50:5, 50:10, etc.; the ball milling time is 2 h, 3 h, 4 h, 5 h, 6 h, etc. By synergistically utilizing the above-mentioned ball milling mixing process parameters, Li2S powder and LiCl powder can be uniformly dispersed to form a Li2S-LiCl composite powder with uniform component distribution.

[0046] In some specific embodiments, the mass ratio of P2S5 powder to Li2S powder is (1~3):1.

[0047] In this embodiment, the mass ratio of P2S5 powder to Li2S powder is determined based on the stoichiometric relationship for generating the target sulfide electrolyte phase. For example, the mass ratio can be selected as 1:1, 1.5:1, 2:1, 2.5:1, 3:1, etc. When the mass ratio is in the range of (1~3:1), the expected shell thickness and coverage can be formed on the surface of the core particles, ensuring that the amount of P2S5 is sufficient to meet the requirements of subsequent solid-phase reactions to generate the sulfide solid electrolyte, thereby improving the compositional uniformity and electrical performance stability of the subsequent sulfide solid electrolyte.

[0048] In some specific embodiments, step S2, which involves heating the P2S5 powder to form P2S5 vapor and depositing the P2S5 vapor onto the particle surface of the Li2S-LiCl composite powder to obtain the sulfide solid electrolyte precursor powder, includes:

[0049] S201: Spread the Li2S-LiCl composite powder evenly in an open first reaction vessel, and place the first reaction vessel in the first temperature zone of the reactor;

[0050] S202: Place P2S5 powder in an open second reaction vessel, and place the second reaction vessel in the second temperature zone of the reactor, with the first temperature zone and the second temperature zone connected by a gas channel;

[0051] S203: Inert gas is introduced into the reactor to create an inert atmosphere inside the reactor;

[0052] S204: Heat the second temperature zone, adjust the gas flow rate of the reactor to a preset flow rate, so that the temperature of the second temperature zone is in the range of 150~450℃, and the temperature of the first temperature zone is in the range of 100~250℃, and the temperature of the second temperature zone is higher than the temperature of the first temperature zone. The P2S5 powder is converted into vapor in the second temperature zone, flows to the first temperature zone, and condenses and deposits on the particle surface of the Li2S-LiCl composite powder in the first temperature zone to form an amorphous P2S5 coating layer.

[0053] S205: After the preset deposition time, heating is stopped, and the reactor is cooled to room temperature under a continuous inert atmosphere. The product in the first reaction vessel is collected, which is the sulfide solid electrolyte precursor powder.

[0054] In this embodiment, in step S201, the Li2S-LiCl composite powder is spread evenly on an open first reaction vessel, and the spreading thickness is controlled within a preset range to ensure sufficient contact of P2S5 vapor. For example, the spreading thickness can be set to 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, etc. The first reaction vessel is, for example, a flat-bottomed ceramic reaction boat, which is placed in the first temperature zone of the reactor.

[0055] In step S202, the second reaction vessel is also an open ceramic reaction boat used to hold the P2S5 powder. The second reaction vessel is placed in the second temperature zone of the reactor, maintaining an appropriate distance from the first reaction vessel. The two are connected by a gas channel inside the reactor to ensure that the P2S5 vapor vaporized in the second temperature zone flows smoothly to the first temperature zone.

[0056] In step S203, the reactor is evacuated and backfilled with high-purity inert gas, and the inert gas flow is maintained. The inert gas can be argon, nitrogen, or a mixture thereof, for example. During the introduction process, the reactor must be purged and replaced first to ensure that the internal air is completely removed. The evacuation-backfilling process is repeated 1 to 5 times.

[0057] In step S204, the temperature of the second temperature zone is set to 150~450℃. For example, 150℃, 200℃, 250℃, 300℃, 350℃, 400℃, and 450℃ can be selected. This range promotes the conversion of P2S5 powder into vapor. Preferably, the temperature of the second temperature zone is set to 300~350℃. The temperature of the first temperature zone is set to 100~250℃. For example, 100℃, 150℃, 200℃, and 250℃ can be selected, and it is always lower than the temperature of the second temperature zone, forming a temperature gradient to drive P2S5 vapor to flow to the first temperature zone and condense and deposit on the surface of the composite powder. In some specific embodiments, the preset gas flow rate is 50~200 sccm. For example, 50 sccm, 80 sccm, 100 sccm, 150 sccm, and 200 sccm can be selected. By adjusting the flow rate, the vapor diffusion rate is controlled, thereby forming a uniformly thick amorphous P2S5 coating layer. In the specific operation, the heating program of the second temperature zone can be started first, raising the temperature of the second temperature zone to a preset temperature of 150~450℃, and then maintaining the temperature for a certain period of time, such as 30~60 minutes, to ensure that the temperature of the second temperature zone is stable and uniform. Subsequently, the temperature distribution along the gas flow path in the reactor is monitored by a temperature detection device (such as a multi-point thermocouple). The area with a stable temperature in the range of 100~250℃ and connected to the second temperature zone through a gas channel is selected as the first temperature zone, ensuring that a stable temperature gradient is formed between the first and second temperature zones. In some specific embodiments, the temperature difference between the second and first temperature zones is 80~150℃. Under the coordinated control of the above temperature difference and the preset gas flow rate, the reactor can provide stable directional diffusion power for P2S5 vapor, so that the diffusion rate of P2S5 vapor matches the condensation and deposition rate, ensuring that P2S5 vapor can uniformly and fully cover the particle surface of Li2S-LiCl composite powder.

[0058] In step S205, in some specific embodiments, the preset deposition time is 30~120 min, and 30 min, 60 min, 90 min, 120 min, etc. can be selected, to ensure that the coating thickness and coating rate reach the expected level. After heating is stopped, the product is naturally cooled or programmed cooled to room temperature under a continuous inert atmosphere. The product collected after cooling is the core-shell structured sulfide solid electrolyte precursor powder.

[0059] This embodiment achieves uniform coating of P2S5 on the surface of Li2S-LiCl composite powder by controlling the generation, diffusion, and deposition of P2S5 vapor, thereby improving the compositional uniformity of the precursor. It achieves uniform and complete coating of P2S5 on the core surface of the Li2S-LiCl composite powder at the atomic / molecular scale, forming a fixed and extremely short solid-phase reaction interface. This significantly shortens the ion diffusion distance and lowers the reaction energy barrier for subsequent preparation of high-performance sulfide solid electrolytes. Furthermore, the shell P2S5 preferentially reacts with trace amounts of water and oxygen in the environment, consuming intruders and providing protection for the internal active core during critical processing periods. This allows the precursor to be processed in industrial-grade drying chambers (e.g., dew point -40°C), greatly reducing reliance on extremely anhydrous and oxygen-free environments such as glove boxes, and significantly lowering industrial production costs.

[0060] In some specific embodiments, during the heating of the second temperature zone, the heating rate of the second temperature zone is 2~10℃ / min;

[0061] And / or, during the cooling process of the reactor, the cooling rate is 1~5℃ / min.

[0062] In this embodiment, during the heating of the second temperature zone, the heating rate of the second temperature zone is exemplarily 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, etc., to avoid local overheating and decomposition due to excessively rapid heating.

[0063] In some specific embodiments, the cooling rate is 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, etc. By controlling the cooling rate, the thermal stress inside the shell can be effectively relieved.

[0064] In some specific embodiments, the reactor is a tubular reactor. The elongated structure of the tubular reactor facilitates the division of an independent and temperature-uniform first temperature zone and a second temperature zone. The unobstructed gas flow path within the tubular reactor is conducive to the directional diffusion of P2S5 vapor carried by inert gas. Using an existing tubular reactor for the preparation of core-shell structure precursors is a simple process with low equipment maintenance costs, enabling continuous production and meeting the needs of industrial applications.

[0065] This application also provides a sulfide solid electrolyte precursor, which is prepared by the preparation method of the sulfide solid electrolyte precursor in any of the above embodiments. The precursor has a core-shell structure, with Li2S-LiCl composite powder as the core and amorphous P2S5 as the shell. The overall particle size of the precursor is 1~10μm and the shell thickness is 3~10nm.

[0066] In this embodiment, the overall particle size of the precursor is 1~10μm. For example, the overall particle size can be selected from 2m, 4μm, 6μm, 8μm, 10μm, etc.; the shell thickness is 3~10nm. For example, 3nm, 5nm, 7nm, 10nm, etc. can be selected.

[0067] This application also provides a method for preparing a sulfide solid electrolyte, which is prepared by using a sulfide solid electrolyte precursor obtained by the preparation method of any of the above embodiments. The method for preparing the sulfide solid electrolyte includes:

[0068] The sulfide solid electrolyte precursor is placed in a sealed container and subjected to heat treatment under an inert atmosphere. The heat treatment temperature is 300~500℃ and the heat treatment duration is 2~10h to obtain the sulfide solid electrolyte.

[0069] In this embodiment, a core-shell structured sulfide solid electrolyte precursor prepared in any of the above embodiments is selected. Since the components in the precursor have formed close contact and uniform dispersion through the core-shell structure, no additional mixing is required. Solid-phase reaction can be driven by heat treatment to generate the sulfide solid electrolyte. The heating rate during the heat treatment is 1~10℃ / min, and the heat treatment temperature is 300~500℃. Exemplarily, 300℃, 350℃, 400℃, 450℃, 500℃, etc., can be selected. Because the core-shell structure of this application shortens the ion diffusion distance and lowers the reaction energy barrier, the heat treatment temperature is significantly lower than that of traditional methods (usually greater than 600℃), achieving energy-saving production. The heat treatment duration is set to 2~10h. Exemplarily, 2h, 4h, 6h, 8h, 10h, etc., can be selected. After the heat treatment, the product is cooled to room temperature at a cooling rate of 2~6℃ / min under an inert atmosphere. The sealed container (e.g., a sealed crucible) is opened to collect the product, which is the sulfide solid electrolyte, such as Li. 5.5 PS 4.5 Cl 1.5 Mutually.

[0070] The preparation method of this embodiment uses a sulfide solid electrolyte precursor that has been pretreated into a core-shell structure, which eliminates the need for additional mixing steps and simplifies the process; the heat treatment temperature is greatly reduced, significantly reducing production energy consumption and costs; and the product has high purity, stable performance, and good consistency.

[0071] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be further described in detail below with reference to the accompanying drawings and several preferred embodiments. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Unless otherwise specified, the test methods in the following embodiments are performed under conventional conditions. Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0072] Example 1

[0073] Step 1: Weigh Li2S powder (3.45g) and LiCl powder (2.39g), place them in a ball mill jar, and premix them by low-energy ball milling at 300rpm for 2h to obtain Li2S-LiCl composite powder;

[0074] Step 2: Spread the Li2S-LiCl composite powder evenly in the first reaction boat (i.e., the first reaction vessel), and place the first reaction boat in the first temperature zone of the tubular reactor;

[0075] Step 3: Weigh 4.17g of purified P2S5 powder and place it in the second reaction boat (i.e., the second reaction vessel). Place the second reaction boat in the second temperature zone of the same tubular reactor, with the first temperature zone and the second temperature zone connected.

[0076] Step 4: Evacuate the tubular reactor and backfill it with high-purity inert gas. Repeat this process 3 times to ensure that the reactor is in an inert atmosphere.

[0077] Step 5: Maintain the inert gas flow and raise the temperature of the second temperature zone to 300℃ at a rate of 2℃ / min to sublimate P2S5 and generate stable vapor. The temperature of the first temperature zone is stabilized at 200℃. The inert gas flow rate is controlled to 100 sccm through the flow controller. The P2S5 vapor is driven to flow to the first temperature zone and condenses and deposits on the particle surface of Li2S-LiCl composite powder to form an amorphous P2S5 coating layer.

[0078] Step 6: After deposition for 60 min, stop heating the second temperature zone, cool the reactor to room temperature at a rate of 3 °C / min, transfer the material in the first reaction boat to the glove box, and collect the obtained core-shell structured sulfide solid electrolyte precursor powder.

[0079] Step 7: Weigh 1g of the core-shell structured sulfide solid electrolyte precursor powder prepared above, place it in a sealed crucible, and heat it to 400℃ at a rate of 2℃ / min under an inert atmosphere, hold it at that temperature for 4 hours, and then cool it to room temperature at a rate of 3℃ / min to obtain high-purity Li. 5.5 PS 4.5 Cl 1.5The product was then placed in a shearing machine and crushed at a speed of 35,000 rpm for 10 seconds each time, for a total of 3 times, to obtain the target product, sulfide solid electrolyte powder.

[0080] Ionic conductivity testing: 100 mg of the prepared sulfide solid electrolyte powder was weighed and placed in a stainless steel pressing mold with an inner diameter of 10 mm. The mold was pressed at 350 MPa to form an electrolyte sheet. Carbon-coated aluminum foil was then added to both sides of the electrolyte sheet. After encapsulation, the sheet was removed and placed in a battery clamp, where it was pressed at 50 MPa to obtain a sandwich-type all-solid-state battery. The ionic conductivity of the solid electrolyte was measured using AC impedance spectroscopy, and the result was σ = 8.7 mS / cm.

[0081] Example 2

[0082] Step 1: Weigh Li2S powder (3.45g) and LiCl powder (2.39g), place them in a ball mill jar, and premix them by low-energy ball milling at 200rpm for 4h to obtain Li2S-LiCl composite powder;

[0083] Step 2: Spread the Li2S-LiCl composite powder evenly in the first reaction boat (i.e., the first reaction vessel), and place the first reaction boat in the first temperature zone of the tubular reactor;

[0084] Step 3: Weigh 4.17g of purified P2S5 powder and place it in the second reaction boat (i.e., the second reaction vessel). Place the second reaction boat in the second temperature zone of the same tubular reactor, with the first temperature zone and the second temperature zone connected.

[0085] Step 4: Evacuate the tubular reactor and backfill it with high-purity inert gas. Repeat this process 3 times to ensure that the reactor is in an inert atmosphere.

[0086] Step 5: Maintain the inert gas flow and raise the temperature of the second temperature zone to 300℃ at a rate of 2℃ / min to sublimate P2S5 and generate stable vapor. The temperature of the first temperature zone is stabilized at 200℃. The inert gas flow rate is controlled to 100 sccm through the flow controller. The P2S5 vapor is driven to flow to the first temperature zone and condenses and deposits on the particle surface of Li2S-LiCl composite powder to form an amorphous P2S5 coating layer.

[0087] Step 6: After deposition for 60 min, stop heating the second temperature zone, cool the reactor to room temperature at a rate of 3 °C / min, transfer the material in the first reaction boat to the glove box, and collect the obtained core-shell structured sulfide solid electrolyte precursor powder.

[0088] Step 7: Weigh 1g of the core-shell structured sulfide solid electrolyte precursor powder prepared above, place it in a sealed crucible, and heat it to 450℃ at a rate of 2℃ / min under an inert atmosphere, hold it at that temperature for 4 hours, and then cool it to room temperature at a rate of 3℃ / min to obtain high-purity Li. 5.5 PS 4.5 Cl 1.5 The product was then placed in a shearing machine and crushed at a speed of 35,000 rpm for 10 seconds each time, for a total of 3 times, to obtain the target product, sulfide solid electrolyte powder.

[0089] Ionic conductivity testing: 100 mg of the prepared sulfide solid electrolyte powder was weighed and placed in a stainless steel pressing mold with an inner diameter of 10 mm. The mold was pressed at 350 MPa to form an electrolyte sheet. Carbon-coated aluminum foil was then added to both sides of the electrolyte sheet. After encapsulation, the sheet was removed and placed in a battery clamp, where it was pressed at 50 MPa to obtain a sandwich-type all-solid-state battery. The ionic conductivity of the solid electrolyte was measured using AC impedance spectroscopy, and the result was σ = 13 mS / cm.

[0090] Example 3

[0091] Step 1: Weigh Li2S powder (3.45g) and LiCl powder (2.39g), place them in a ball mill jar, and premix them by low-energy ball milling at 100rpm for 6h to obtain Li2S-LiCl composite powder;

[0092] Step 2: Spread the Li2S-LiCl composite powder evenly in the first reaction boat (i.e., the first reaction vessel), and place the first reaction boat in the first temperature zone of the tubular reactor;

[0093] Step 3: Weigh 4.17g of purified P2S5 powder and place it in the second reaction boat (i.e., the second reaction vessel). Place the second reaction boat in the second temperature zone of the same tubular reactor, with the first temperature zone and the second temperature zone connected.

[0094] Step 4: Evacuate the tubular reactor and backfill it with high-purity inert gas. Repeat this process 3 times to ensure that the reactor is in an inert atmosphere.

[0095] Step 5: Maintain the inert gas flow and raise the temperature of the second temperature zone to 450℃ at a rate of 10℃ / min to sublimate P2S5 and generate stable vapor. The temperature of the first temperature zone is stabilized at 250℃. The inert gas flow rate is controlled to 200 sccm by the flow controller. The P2S5 vapor is driven to flow to the first temperature zone and condenses and deposits on the particle surface of Li2S-LiCl composite powder to form an amorphous P2S5 coating layer.

[0096] Step 6: After deposition for 60 min, stop heating the second temperature zone, cool the reactor to room temperature at a rate of 5 °C / min, transfer the material in the first reaction boat to the glove box, and collect the obtained core-shell structured sulfide solid electrolyte precursor powder.

[0097] Step 7: Weigh 1g of the core-shell structured sulfide solid electrolyte precursor powder prepared above, place it in a sealed crucible, and heat it to 500℃ at a rate of 2℃ / min under an inert atmosphere, hold it at that temperature for 4 hours, and then cool it to room temperature at a rate of 3℃ / min to obtain high-purity Li. 5.5 PS 4.5 Cl 1.5 The product was then placed in a shearing machine and crushed at a speed of 35,000 rpm for 10 seconds each time, for a total of 3 times, to obtain the target product, sulfide solid electrolyte powder.

[0098] Ionic conductivity testing: 100 mg of the prepared sulfide solid electrolyte powder was weighed and placed in a stainless steel pressing mold with an inner diameter of 10 mm. The mold was pressed at 350 MPa to form an electrolyte sheet. Carbon-coated aluminum foil was then added to both sides of the electrolyte sheet. After encapsulation, the sheet was removed and placed in a battery clamp, where it was pressed at 50 MPa to obtain a sandwich-type all-solid-state battery. The ionic conductivity of the solid electrolyte was measured using AC impedance spectroscopy, and the result was σ = 8.7 mS / cm.

[0099] Example 4

[0100] Step 1: Weigh Li2S powder (3.45g) and LiCl powder (2.39g), place them in a ball mill jar, and premix them by low-energy ball milling at 200rpm for 4h to obtain Li2S-LiCl composite powder;

[0101] Step 2: Spread the Li2S-LiCl composite powder evenly in the first reaction boat (i.e., the first reaction vessel), and place the first reaction boat in the first temperature zone of the tubular reactor;

[0102] Step 3: Weigh 4.17g of purified P2S5 powder and place it in the second reaction boat (i.e., the second reaction vessel). Place the second reaction boat in the second temperature zone of the same tubular reactor, with the first temperature zone and the second temperature zone connected.

[0103] Step 4: Evacuate the tubular reactor and backfill it with high-purity inert gas. Repeat this process 3 times to ensure that the reactor is in an inert atmosphere.

[0104] Step 5: Maintain the inert gas flow and raise the temperature of the second temperature zone to 300℃ at a rate of 5℃ / min to sublimate P2S5 and generate stable vapor. The temperature of the first temperature zone is stabilized at 200℃. The inert gas flow rate is controlled to 100 sccm through the flow controller. The P2S5 vapor is driven to flow to the first temperature zone and condenses and deposits on the particle surface of Li2S-LiCl composite powder to form an amorphous P2S5 coating layer.

[0105] Step 6: After deposition for 30 min, stop heating the second temperature zone, cool the reactor to room temperature at a rate of 3℃ / min, transfer the material in the first reaction boat to the glove box, and collect the obtained core-shell structured sulfide solid electrolyte precursor powder.

[0106] Step 7: Weigh 1g of the core-shell structured sulfide solid electrolyte precursor powder prepared above, place it in a sealed crucible, and heat it to 450℃ at a rate of 2℃ / min under an inert atmosphere, hold it at that temperature for 4 hours, and then cool it to room temperature at a rate of 3℃ / min to obtain high-purity Li. 5.5 PS 4.5 Cl 1.5 The product was then placed in a shearing machine and crushed at a speed of 35,000 rpm for 10 seconds each time, for a total of 3 times, to obtain the target product, sulfide solid electrolyte powder.

[0107] Ionic conductivity testing: 100 mg of the prepared sulfide solid electrolyte powder was weighed and placed in a stainless steel pressing mold with an inner diameter of 10 mm. The mold was pressed at 350 MPa to form an electrolyte sheet. Carbon-coated aluminum foil was then added to both sides of the electrolyte sheet. After encapsulation, the sheet was removed and placed in a battery clamp, where it was pressed at 50 MPa to obtain a sandwich-type all-solid-state battery. The ionic conductivity of the solid electrolyte was measured using AC impedance spectroscopy, and the result was σ = 9.4 mS / cm.

[0108] Example 5

[0109] Step 1: Weigh Li2S powder (3.45g) and LiCl powder (2.39g), place them in a ball mill jar, and premix them by low-energy ball milling at 200rpm for 4h to obtain Li2S-LiCl composite powder;

[0110] Step 2: Spread the Li2S-LiCl composite powder evenly in the first reaction boat (i.e., the first reaction vessel), and place the first reaction boat in the first temperature zone of the tubular reactor;

[0111] Step 3: Weigh 4.17g of purified P2S5 powder and place it in the second reaction boat (i.e., the second reaction vessel). Place the second reaction boat in the second temperature zone of the same tubular reactor, with the first temperature zone and the second temperature zone connected.

[0112] Step 4: Evacuate the tubular reactor and backfill it with high-purity inert gas. Repeat this process 3 times to ensure that the reactor is in an inert atmosphere.

[0113] Step 5: Maintain the inert gas flow and raise the temperature of the second temperature zone to 150°C at a rate of 2°C / min to sublimate P2S5 and generate stable vapor. The temperature of the first temperature zone is stabilized at 100°C. The inert gas flow rate is controlled to 50 sccm by the flow controller. The P2S5 vapor is driven to flow to the first temperature zone and condenses and deposits on the particle surface of Li2S-LiCl composite powder to form an amorphous P2S5 coating layer.

[0114] Step 6: After deposition for 120 min, stop heating the second temperature zone, cool the reactor to room temperature at a rate of 1℃ / min, transfer the material in the first reaction boat to the glove box, and collect the obtained core-shell structured sulfide solid electrolyte precursor powder.

[0115] Step 7: Weigh 1g of the core-shell structured sulfide solid electrolyte precursor powder prepared above, place it in a sealed crucible, and heat it to 300℃ at a rate of 2℃ / min under an inert atmosphere, hold it at that temperature for 10 hours, and then cool it to room temperature at a rate of 3℃ / min to obtain high-purity Li. 5.5 PS 4.5 Cl 1.5 The product was then placed in a shearing machine and crushed at a speed of 35,000 rpm for 10 seconds each time, for a total of 3 times, to obtain the target product, sulfide solid electrolyte powder.

[0116] Ionic conductivity testing: 100 mg of the prepared sulfide solid electrolyte powder was weighed and placed in a stainless steel pressing mold with an inner diameter of 10 mm. The mold was pressed at 350 MPa to form an electrolyte sheet. Carbon-coated aluminum foil was then added to both sides of the electrolyte sheet. After encapsulation, the sheet was removed and placed in a battery clamp, where it was pressed at 50 MPa to obtain a sandwich-type all-solid-state battery. The ionic conductivity of the solid electrolyte was measured using AC impedance spectroscopy, and the result was σ = 7.2 mS / cm.

[0117] Example 6

[0118] The difference between Example 6 and Example 2 is that steps six and seven are carried out in a dry room with a dew point of -40°C, while the rest are the same as in Example 2.

[0119] Ionic conductivity testing: 100 mg of the prepared sulfide solid electrolyte powder was weighed and placed in a stainless steel pressing mold with an inner diameter of 10 mm. The mold was pressed at 350 MPa to form an electrolyte sheet. Carbon-coated aluminum foil was then added to both sides of the electrolyte sheet. After encapsulation, the sheet was removed and placed in a battery clamp, where it was pressed at 50 MPa to obtain a sandwich-type all-solid-state battery. The ionic conductivity of the solid electrolyte was measured using AC impedance spectroscopy, and the result was σ = 8.0 mS / cm.

[0120] Comparative Example 1

[0121] Step 1: Weigh Li2S powder (3.45g), LiCl powder (2.39g) and purified P2S5 powder (4.17g), place them in a ball mill jar, and premix them by low-energy ball milling at 300rpm for 4h to obtain Li2S-LiCl-P2S5 composite powder.

[0122] Step 2: Weigh 1g of the Li₂S-LiCl-P₂S₅ composite powder obtained in Step 1, place it in a sealed crucible, and heat it to 450℃ at a rate of 2℃ / min under an inert atmosphere, hold it at that temperature for 4 hours, and then cool it to room temperature at a rate of 3℃ / min to obtain Li 5.5 PS 4.5 Cl 1.5 The product was then placed in a shearing machine and crushed at a speed of 35,000 rpm for 10 seconds each time, for a total of 3 times, to obtain the target product, sulfide solid electrolyte powder.

[0123] Ionic conductivity testing: 100 mg of the prepared sulfide solid electrolyte powder was weighed and placed in a stainless steel pressing mold with an inner diameter of 10 mm. The mold was pressed at 350 MPa to form an electrolyte sheet. Carbon-coated aluminum foil was then added to both sides of the electrolyte sheet. After encapsulation, the sheet was removed and placed in a battery clamp, where it was pressed at 50 MPa to obtain a sandwich-type all-solid-state battery. The ionic conductivity of the solid electrolyte was measured using AC impedance spectroscopy, and the result was σ = 1.1 mS / cm.

[0124] Comparative Example 2

[0125] The difference between Comparative Example 2 and Comparative Example 1 is that the calcination temperature in step two is 600℃, while the rest is the same as Comparative Example 1.

[0126] Ionic conductivity testing: 100 mg of the prepared sulfide solid electrolyte powder was weighed and placed in a stainless steel pressing mold with an inner diameter of 10 mm. The mold was pressed at 350 MPa to form an electrolyte sheet. Carbon-coated aluminum foil was then added to both sides of the electrolyte sheet. After encapsulation, the sheet was removed and placed in a battery clamp, where it was pressed at 50 MPa to obtain a sandwich-type all-solid-state battery. The ionic conductivity of the solid electrolyte was measured using AC impedance spectroscopy, and the result was σ = 2.1 mS / cm.

[0127] The sulfide solid electrolyte precursor prepared in Example 2 was subjected to TEM testing, and the results are as follows: Figure 1 As shown, the precursor exhibits a core-shell structure with a shell thickness of approximately 6 nm.

[0128] XRD tests were performed on the sulfide solid electrolytes prepared in Example 2 and Comparative Example 1. The spectra were compared with those of Example 2. Figure 2 As shown, the XRD peaks corresponding to Example 2 are completely matched with the standard PDF card (JCPDS#34-0688) of Li7PS6, indicating that the electrolyte prepared in Example 2 is a pure phase; the XRD peaks corresponding to Comparative Example 1 have obvious lithium sulfide impurity peaks at θ=29.20, indicating that Comparative Example 1 contains residual lithium sulfide phase caused by incomplete reaction.

[0129] The impedance and ionic conductivity of the sulfide solid electrolytes in Examples 1-6 and Comparative Examples 1-2 were tested using the AC impedance method, and the results are shown in Table 1. The impedance test results for Examples 1-6 are as follows: Figure 3 As shown, the impedance test results of Comparative Examples 1 and 2 are as follows: Figure 4 As shown.

[0130] Table 1

[0131] Impedance (Ω) Ionic conductivity (mS / cm) Example 1 9.6 10 Example 2 7.0 13 Example 3 10.8 8.7 Example 4 9.4 9.4 Example 5 13.1 7.2 Example 6 11.7 8.0 Comparative Example 1 80 1.1 Comparative Example 2 43 2.1

[0132] From Table 1 and Figure 3 , Figure 4 It is evident that the impedance of Examples 1-6 is significantly lower than that of Comparative Examples 1-2, indicating that the ion transport resistance of the sulfide solid electrolyte prepared in this application is significantly reduced, and the ion conduction performance is greatly improved. It is evident that the sulfide solid electrolyte precursor of this application, through its core-shell structure design, significantly improves the mixing uniformity of each component at the microscopic level, achieving uniform and complete coating of P2S5 on the core surface of the Li2S-LiCl composite powder at the atomic / molecular scale. This forms a stable and extremely short solid-phase reaction interface, ensuring a highly uniform reaction path for subsequent heat treatment, ultimately yielding a high-purity, high-performance sulfide solid electrolyte and significantly improving product consistency. Simultaneously, the core-shell structure pre-positions the reactants in nanoscale close contact, greatly shortening the ion diffusion distance and lowering the reaction energy barrier. This not only significantly reduces the temperature and time of subsequent synthesis, achieving energy-efficient production, but also effectively avoids high-temperature side reactions.

[0133] A comparison of Examples 2 and 6 further demonstrates that, because the precursor in this application is prepared as a core-shell structure, its amorphous P2S5 shell can preferentially react with trace amounts of water and oxygen in the environment, thereby protecting the activity of the internal core components. Specifically, Example 6 was processed only in an industrial-grade drying chamber (dew point -40°C), and the resulting sulfide solid electrolyte exhibited impedance and ionic conductivity only slightly lower than that of Example 2, which was processed in a glove box (extremely anhydrous and oxygen-free environment). Compared to the product prepared by conventional methods in Comparative Example 1, the electrochemical performance of Example 6 still showed a significant leap. This result indicates that using a core-shell structure precursor to prepare sulfide solid electrolytes can significantly reduce dependence on extremely anhydrous and oxygen-free environments (such as glove boxes), effectively compressing the environmental control costs of industrial-scale production.

[0134] The preparation method of this application, by pre-preparing a core-shell structured sulfide solid electrolyte precursor, can produce a high-purity sulfide solid electrolyte with ionic conductivity far superior to traditional preparation methods. This method not only features a simple and easily controllable preparation process but also significantly reduces reliance on an extremely anhydrous oxygen environment (such as a glove box). Furthermore, the significantly reduced heat treatment temperature effectively lowers production energy consumption and costs, demonstrating promising industrial application prospects in fields such as all-solid-state batteries.

[0135] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. A method for preparing a sulfide solid electrolyte precursor, characterized in that, The preparation method of the sulfide solid electrolyte precursor includes: Li2S powder and LiCl powder are mixed to obtain Li2S-LiCl composite powder; P2S5 powder is heated to form P2S5 vapor, and the P2S5 vapor is deposited on the particle surface of the Li2S-LiCl composite powder to obtain a sulfide solid electrolyte precursor powder. The precursor has a core-shell structure, with the Li2S-LiCl composite powder as the core and amorphous P2S5 coating the particle surface of the Li2S-LiCl composite powder as the shell.

2. The method for preparing the sulfide solid electrolyte precursor as described in claim 1, characterized in that, The step of mixing Li2S powder and LiCl powder to obtain Li2S-LiCl composite powder. include: Weigh out Li2S powder and LiCl powder in a mass ratio of (1~5):1 and place them in a ball mill jar for ball milling and mixing. The ball milling speed is 100~300 rpm and the ball milling time is 2~6 hours.

3. The method for preparing the sulfide solid electrolyte precursor as described in claim 1, characterized in that, The mass ratio of P2S5 powder to Li2S powder is (1~3):

1.

4. The method for preparing the sulfide solid electrolyte precursor as described in claim 1, characterized in that, The step of heating P2S5 powder to form P2S5 vapor and depositing the P2S5 vapor on the particle surface of the Li2S-LiCl composite powder to obtain sulfide solid electrolyte precursor powder includes: The Li2S-LiCl composite powder is spread evenly in an open first reaction vessel, and the first reaction vessel is placed in the first temperature zone of the reactor; P2S5 powder is placed in an open second reaction vessel, and the second reaction vessel is placed in the second temperature zone of the reactor, with the first temperature zone and the second temperature zone connected by a gas channel; An inert gas is introduced into the reactor to create an inert atmosphere inside the reactor. The second temperature zone is heated, and the gas flow rate of the reactor is adjusted to a preset flow rate so that the temperature of the second temperature zone is in the range of 150~450℃, and the temperature of the first temperature zone is in the range of 100~250℃. The temperature of the second temperature zone is higher than that of the first temperature zone. The P2S5 powder is converted into vapor in the second temperature zone, flows to the first temperature zone, and condenses and deposits on the particle surface of the Li2S-LiCl composite powder in the first temperature zone to form an amorphous P2S5 coating layer. After a preset deposition time, heating is stopped, and the reactor is cooled to room temperature under a continuous inert atmosphere. The product in the first reaction vessel is then collected, which is the sulfide solid electrolyte precursor powder.

5. The method for preparing the sulfide solid electrolyte precursor as described in claim 4, characterized in that, During the heating of the second temperature zone, the heating rate of the second temperature zone is 2~10℃ / min; And / or, during the cooling process of the reactor, the cooling rate is 1~5℃ / min.

6. The method for preparing the sulfide solid electrolyte precursor as described in claim 4, characterized in that, The preset flow rate is 50~200 sccm.

7. The method for preparing the sulfide solid electrolyte precursor as described in claim 4, characterized in that, The preset deposition time is 30~120 min.

8. The method for preparing the sulfide solid electrolyte precursor as described in claim 4, characterized in that, The reactor is a tubular reactor; And / or, the inert gas includes at least one of argon and nitrogen.

9. A sulfide solid electrolyte precursor, characterized in that, The precursor is prepared by the method for preparing a sulfide solid electrolyte precursor as described in any one of claims 1-8. The precursor has a core-shell structure, with Li2S-LiCl composite powder as the core and amorphous P2S5 as the shell. The overall particle size of the precursor is 1~10μm and the shell thickness is 3~10nm.

10. A method for preparing a sulfide solid electrolyte, characterized in that, The sulfide solid electrolyte precursor is prepared using the preparation method of the sulfide solid electrolyte precursor as described in any one of claims 1-8, wherein the preparation method of the sulfide solid electrolyte includes: The sulfide solid electrolyte precursor is placed in a sealed container and subjected to heat treatment under an inert atmosphere. The heat treatment temperature is 300~500℃ and the heat treatment duration is 2~10h to obtain the sulfide solid electrolyte.

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