Partitioned ionically regulated sulfide solid-state electrolyte membranes, solid-state batteries, and methods of preparation

Abstract

The application discloses a partition ion regulation type sulfide solid electrolyte film, a solid-state battery and a preparation method. The solid electrolyte film comprises a sheet-shaped film body which is a sulfide solid electrolyte, a groove is arranged on one side of the film body, and the groove divides the film body plane into a plurality of array-distributed lateral ion transmission sub-zones. An ion flow limiting connecting part is arranged in the groove to separate adjacent lateral ion transmission sub-zones to form limited communication. Through the spatial structure design of discrete partition and the functional design of the ion flow limiting connecting part, the application realizes the partition regulation and fault localization control of lithium ion transmission, ensures the ion conduction performance of the whole solid electrolyte, effectively limits the cross-zone growth of lithium dendrites, blocks the electron leakage path and prevents the global expansion of cracks, significantly improves the anti-dendrite ability and structural stability of the sulfide solid electrolyte, and further greatly improves the cycle stability and use safety of the solid-state battery.

Description

Technical Field

[0001] This invention belongs to the field of solid-state lithium battery technology, and particularly relates to a partitioned ion-controlled sulfide solid electrolyte membrane, a solid-state battery using the sulfide solid electrolyte membrane, and a method for preparing the sulfide solid electrolyte membrane. Background Technology

[0002] With the development of high-energy-density energy storage technologies, solid-state batteries using lithium metal anodes are gradually becoming an important development direction for next-generation battery technology due to their high theoretical specific capacity and good safety potential. In solid-state battery systems, the solid electrolyte not only undertakes the lithium-ion transport function but also directly affects the electrode interface stability, battery cycle life, and overall safety. Among them, sulfide solid electrolytes are considered one of the most promising solid electrolyte systems due to their high room-temperature ionic conductivity, good cold-pressing performance, and low interfacial impedance.

[0003] However, in practical applications, sulfide solid electrolytes are still prone to lithium dendrite growth and the resulting internal short circuits. Studies show that lithium dendrite formation is usually related to multiple factors: First, at the interface between the lithium metal anode and the solid electrolyte, uneven contact, uneven electric field distribution, or local ion flux differences can lead to preferential deposition of lithium ions in localized areas, forming dendrites. Second, structural defects such as grain boundaries, pores, or microcracks within the solid electrolyte can become preferred sites for electron accumulation or lithium ion reduction, inducing lithium deposition within the electrolyte and propagation along defects. Furthermore, some sulfide solid electrolytes may possess a certain electronic conductivity under the influence of defects or impurities, providing an electron source for lithium ion reduction within the electrolyte; simultaneously, under higher current density conditions, the lithium ion deposition rate may exceed its uniform diffusion rate in the electrolyte, further promoting dendrite growth; on the other hand, the volume changes generated by lithium metal during charging and discharging can also induce mechanical stress, causing cracks or defects within the electrolyte, providing pathways for dendrite propagation.

[0004] Lithium dendrites typically grow preferentially at the electrode-electrolyte interface, solid electrolyte grain boundaries, and in defective regions such as pores or cracks within the electrolyte. Once dendrites continue to grow along these low-resistivity paths, they can easily penetrate the electrolyte layer and cause internal short circuits in the battery.

[0005] Existing technologies typically suppress dendrite growth by increasing electrolyte density, introducing insulating fillers, or optimizing interface structure. However, most of these methods are based on a globally homogeneous structure design. Once dendrite growth or electron leakage occurs in a localized area, the failure can still rapidly propagate along a continuous transport path within the electrolyte, making it difficult to achieve localized fault control. Summary of the Invention

[0006] The first objective of this invention is to provide a partitioned ion-regulated sulfide solid electrolyte membrane that can improve safety and cycle stability.

[0007] The first objective of this invention is achieved through the following technical measures: a partitioned ion-controlled sulfide solid electrolyte membrane, comprising a sheet-like membrane body that is a sulfide solid electrolyte, characterized in that a groove is formed on one side plane of the membrane body, and the groove divides the membrane body plane into a plurality of transverse ion transport sub-regions arranged in an array, and an ion current-limiting connection portion is provided in the groove to separate adjacent transverse ion transport sub-regions so that they form a restricted connection.

[0008] This invention achieves partitioned regulation of lithium-ion transport and localized fault control through discrete partitioned spatial structure design and functional design of ion current limiting connection. It not only ensures the overall ion conduction performance of the solid electrolyte, but also effectively limits the cross-regional growth of lithium dendrites, blocks electron leakage paths, and prevents the global propagation of cracks. This significantly improves the anti-dendrite ability and structural stability of sulfide solid electrolytes, thereby greatly improving the cycle stability and safety of solid batteries.

[0009] The thickness of the solid electrolyte membrane of the present invention is 20 μm to 60 μm, and the thickness of the ion current limiting connection is 80% to 98% of the thickness of the solid electrolyte membrane.

[0010] The planar feature size of the lateral ion transport sub-region described in this invention is 200μm to 800μm, and the planar area of ​​the entire lateral ion transport sub-region accounts for 85% to 95% of the planar area of ​​the solid electrolyte membrane. The width of the ion current limiting connection is 5μm to 30μm, and the planar area of ​​the entire ion current limiting connection accounts for 5% to 15% of the planar area of ​​the solid electrolyte membrane.

[0011] Under conditions of 30°C, the room temperature ionic conductivity of the transverse ion transport sub-region of this invention is not less than 1 mS / cm, the ionic conductivity of the ion current limiting connection is 5% to 25% of the ionic conductivity of the transverse ion transport sub-region, and the electronic conductivity of the ion current limiting connection is not higher than 1×10⁻⁶ mS / cm. -10 The surface ion resistance ratio between the ion current limiting connection and the transverse ion transport sub-region is 8:1 to 15:1 (S / cm).

[0012] Under 30°C conditions, the fracture toughness of the ion-limiting connection in this invention is 0.7–1.5 MPa·m. 1 / 2 It also exhibits fracture toughness that is more than 20% higher than that of materials in the transverse ion transporter region.

[0013] The composite material used in the ion-limiting connection of the present invention is composed of the following components by mass percentage:

[0014] Sulfide solid electrolyte, 65%–80%;

[0015] Electronic insulation reinforcement material, 15%–25%;

[0016] Structural reinforcing adhesive, 5%–10%;

[0017] The sum of the mass percentages of all components is 100%.

[0018] The electronic insulation reinforcement material of the present invention adopts at least one of Al2O3, LiNbO3 and Li3PO4, and the particle size of the electronic insulation reinforcement material is 20 nm to 200 nm.

[0019] A second objective of this invention is to provide a solid-state battery using the aforementioned partitioned ion-regulated sulfide solid electrolyte membrane.

[0020] The second objective of the present invention is achieved by the following technical measures: a solid-state battery using the above-mentioned partitioned ion-controlled sulfide solid electrolyte membrane, characterized in that it includes a positive electrode, a negative electrode, and the partitioned ion-controlled sulfide solid electrolyte membrane located between the positive electrode and the negative electrode.

[0021] The positive electrode of the present invention comprises a positive electrode active material, a conductive agent and a binder, wherein the positive electrode active material is at least one of layered oxide, spinel oxide, olivine phosphate and sulfur positive electrode material.

[0022] The second objective of this invention is to provide a method for preparing the above-mentioned partitioned ion-regulated sulfide solid electrolyte membrane.

[0023] The second objective of this invention is achieved through the following technical measures: a method for preparing the above-mentioned partitioned ion-regulated sulfide solid electrolyte membrane, characterized in that the following steps are performed in a high-purity nitrogen environment:

[0024] S1. Preparation of an initial dense membrane for a sulfide solid electrolyte;

[0025] S2. Grooves are formed on the surface of the initial dense membrane according to an array pattern to obtain a patterned electrolyte membrane.

[0026] S3. Fill the groove with ion-limiting connection slurry and dry it to form ion-limiting connection;

[0027] S4. The electrolyte membrane that has been filled and dried with slurry is densified by room temperature cold pressing, then densified by medium and low temperature hot pressing, and finally cooled to room temperature to obtain a partitioned ion-controlled sulfide solid electrolyte membrane.

[0028] Compared with the prior art, the present invention has the following significant effects:

[0029] (1) This invention performs zoned regulation of the ion transport path of solid electrolytes, establishing restricted ion connectivity and local current-limiting mechanisms between adjacent transverse ion transport sub-regions. This restricts electron leakage, lithium dendrite growth, or crack propagation in local areas to a single region or a few adjacent regions. This not only maintains a certain lithium-ion conductivity at the ion-limiting connection, but also significantly improves the electronic insulation and mechanical fracture toughness of the ion-limiting connection. At the same time, it effectively regulates the ion migration rate across sub-regions, thereby synergistically achieving the goals of limiting ion planar diffusion, blocking electron leakage, inhibiting lithium dendrite extension, and preventing crack propagation, thus improving the safety and cycle stability of sulfide solid electrolytes and their solid batteries.

[0030] (2) The preparation method of the present invention has controllable process parameters, is easy to operate and highly repeatable, and is suitable for laboratory preparation and large-scale production, and has good industrial application prospects. Attached Figure Description

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0032] Figure 1 is a schematic diagram of the planar structure of the solid electrolyte membrane of the present invention;

[0033] Figure 2 This is a schematic cross-sectional view of the solid electrolyte membrane of the present invention;

[0034] Figure 3 This is one of the schematic diagrams of dendrite propagation paths in the solid electrolyte membrane of the present invention;

[0035] Figure 4 This is the second schematic diagram of the dendrite propagation path in the solid electrolyte membrane of this invention. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the embodiments and accompanying drawings to help those skilled in the art better understand the inventive concept of the present invention. However, the scope of protection of the claims of the present invention is not limited to the following embodiments. For those skilled in the art, all other embodiments obtained without creative effort without departing from the inventive concept of the present invention are within the scope of protection of the present invention.

[0037] like Figure 1 , Figure 2As shown, a partitioned ion-controlled sulfide solid electrolyte membrane includes a sheet-like membrane body that is a sulfide solid electrolyte. Grooves are formed on one side plane of the membrane body, and the grooves divide the membrane body plane into a plurality of transverse ion transport sub-regions 1 arranged in an array. Ion current limiting connection portions 2 are provided in the grooves to separate adjacent transverse ion transport sub-regions 1 so that they form a restricted connection.

[0038] The lateral ion transport sub-region 1 and the ion current limiting connection 2 form a discrete partitioned structure in the planar direction. The lateral ion transport sub-region 1 is the main ion transport region in the solid electrolyte membrane. Multiple lateral ion transport sub-regions 1 are distributed in an array, which can be a hexagonal honeycomb array, a square array, or a regular polygonal array. Among them, the hexagonal honeycomb array is preferred because it has higher filling efficiency and more uniform stress distribution.

[0039] The thickness direction A of the solid electrolyte membrane is as follows Figure 2 As shown, the thickness of the solid electrolyte membrane is 20μm to 60μm to ensure that the solid electrolyte membrane has sufficient mechanical stability, while also reducing the ion transport impedance of the solid battery. The preferred thickness is 30μm to 50μm.

[0040] The thickness of the ion current limiting connection 2 accounts for 80% to 98% of the thickness of the solid electrolyte membrane, so that adjacent transverse ion transport sub-regions 1 form a restricted connection. The proportion of the ion current limiting connection 2 to the thickness of the solid electrolyte membrane is preferably 90% to 98%. Through this structural design, there is no bottom continuous ion transport channel between adjacent transverse ion transport sub-regions, thereby ensuring that ion cross-region migration is mainly achieved through the ion current limiting connection 2.

[0041] The planar feature size of the lateral ion transport sub-region 1 is 200 μm to 800 μm, preferably 300 μm to 800 μm. The structure corresponding to the planar feature size is preferably a hexagonal honeycomb array, as shown in Figure 1. Within this size range, the overall ion conduction continuity of the electrolyte can be guaranteed, while also creating spatial confinement for local failure areas.

[0042] The planar area of ​​all transverse ion transport sub-regions accounts for 85% to 95% of the planar area of ​​the solid electrolyte, preferably 88% to 92%. When the planar area of ​​the transverse ion transport sub-regions is less than 85%, the overall ionic conductivity of the solid electrolyte membrane will decrease significantly. When it is higher than 95%, the number of ion current limiting connections is reduced, which is not conducive to achieving effective current limiting and fault isolation.

[0043] At 30°C, the room-temperature ionic conductivity of the transverse ion transport region is not less than 1 mS / cm, preferably in the range of 2 mS / cm to 6 mS / cm. The transverse ion transport region is a sulfide solid electrolyte, which can be selected from Li6PS5Cl, Li6PS5Br, and Li7P3S. 11 Li 10 GeP2S 12 One or more of the following, with a purity ≥99.9%, preferably Li6PS5Cl.

[0044] The ion current limiting connection 2 is located between adjacent transverse ion transport sub-regions 1. Its main function is to limit the ion migration rate between transverse ion transport sub-regions 1, block the electron leakage path, improve the structural fracture toughness, and prevent crack propagation. The planar width of the ion current limiting connection 2 is 5μm to 30μm, preferably 8μm to 20μm. The planar area of ​​the ion current limiting connection 2 accounts for 5% to 15% of the planar area of ​​the solid electrolyte membrane, preferably 8% to 12%.

[0045] At 30°C, the ionic conductivity of the ion-limiting connection is 5%–25% of the ionic conductivity of the transverse ion transport subregion, preferably 10%–20%. Simultaneously, its electronic conductivity is not higher than 1×10⁻⁶. -10 S / cm, preferably not higher than 5×10 -11 The surface ion resistivity ratio between the ion current-limiting connection and the transverse ion transport subregion is 8:1 to 15:1, preferably 10:1 to 13:1. This resistivity ratio effectively suppresses rapid ion diffusion in the planar direction, thereby achieving local current limiting. Furthermore, the fracture toughness of the ion current-limiting connection is 0.7 to 1.5 MPa·m. 1 / 2 Preferably 1.0–1.3 MPa·m 1 / 2 Furthermore, the fracture toughness of the ion-limiting connection is improved by at least 20% compared to the fracture toughness of the transverse ion transport sub-region material, preferably by 25% to 35%. This characteristic gives the ion-limiting connection a stronger crack-blocking capability in its structure.

[0046] The composite material used in the ion current limiting material connector is composed of the following components by mass percentage:

[0047] Sulfide solid electrolyte: 65%–80%, preferably 70%–75%;

[0048] Electronic insulation reinforcement material: 15%–25%, preferably 18%–22%;

[0049] Structural reinforcing adhesive: 5%–10%, preferably 6%–8%;

[0050] The sum of the mass percentages of all components is 100%.

[0051] The electronic insulation reinforcement material is selected from one or more of Al2O3, LiNbO3 and Li3PO4, preferably nano-Al2O3; its particle size is 20 nm to 200 nm, preferably 30 nm to 100 nm. Within this particle size range, the electronic insulation effect can be guaranteed, and it is not easy to form large-size agglomeration defects inside the connection part, which is beneficial to improving the densification degree and mechanical uniformity.

[0052] The structurally reinforcing adhesive is selected from polyethylene oxide (PEO), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) or other polymer adhesive materials, preferably polyethylene oxide (PEO), which has good compatibility with sulfide solid electrolytes and can achieve bonding and toughening at lower temperatures, avoiding electrolyte decomposition caused by high-temperature processing.

[0053] The aforementioned composite material can maintain a certain lithium-ion conductivity in the ion-limiting connection, significantly improve the electronic insulation and mechanical fracture toughness of the ion-limiting connection, and effectively regulate the ion migration rate across the sub-region, thereby synergistically achieving the goals of limiting ion planar diffusion, blocking electron leakage, inhibiting lithium dendrite extension, and preventing crack propagation.

[0054] The working mechanism of this invention is as follows Figure 3 , Figure 4 As shown, when localized electron leakage or abnormal lithium deposition occurs at the electrode-electrolyte interface, lithium dendrites 3 preferentially grow in localized regions and continue to grow along low-resistance paths. This invention, by constructing an ion-limiting connection 2 in the planar direction with a significantly higher surface ion resistance than the lateral ion transport sub-region 1, significantly increases the ion flux and electrochemical driving force required for dendrite cross-region expansion, thereby confining dendrite growth and related failures to a single sub-region or a few adjacent sub-regions, achieving localized fault control.

[0055] A solid-state battery using the above-mentioned partitioned ion-controlled sulfide solid electrolyte membrane includes a positive electrode, a negative electrode, and a partitioned ion-controlled sulfide solid electrolyte membrane located between the positive electrode and the negative electrode.

[0056] The negative electrode is selected from lithium metal negative electrode, lithium alloy negative electrode, thin lithium negative electrode or negative electrode-less current collector negative electrode, preferably lithium metal foil with a thickness of 20-50 μm, and the total thickness of the negative electrode is controlled to be 20-80 μm; the positive electrode includes positive electrode active material, conductive agent and binder, wherein the positive electrode active material is selected from at least one of layered oxide (NCM811 / NCA), spinel oxide (LMO), olivine phosphate (LFP) and sulfur positive electrode material, the thickness of the positive electrode sheet is 30-80 μm, and the areal capacity is 2.0-5.0 mAh / cm².

[0057] The assembly process of this solid-state battery is as follows: the positive electrode, solid electrolyte membrane, and negative electrode are stacked in a nitrogen glove box in that order. During the assembly process, a stacking pressure of 5 to 15 MPa is applied to ensure that the positive electrode, solid electrolyte membrane, and negative electrode are in close contact without any interface gaps. After the assembly is completed, the solid-state battery is obtained.

[0058] A method for preparing the above-mentioned partitioned ion-regulated sulfide solid electrolyte, wherein all operations are carried out in a nitrogen glove box (O2 / H2O < 0.1 ppm), includes the following steps:

[0059] S1. Preparation of an initial dense membrane for a sulfide solid electrolyte;

[0060] Sulfide solid electrolyte powder is mixed with 0.5–1 wt% of a polymer binder, preferably PEO, with an addition amount of 0.6–0.8 wt%. The powder is uniformly mixed using ball milling with a ball-to-powder ratio of 20:1, a rotation speed of 300 rpm, and a milling time of 15 h. The milled powder is then placed in a mold for room temperature cold pressing at a pressure of 200 MPa, preferably 190–210 MPa, and a pressing time of 3 min, preferably 2.5–3.5 min, to obtain a preliminary compacted film with a thickness of 30–50 μm, preferably 35–45 μm. Subsequently, the preliminary compacted film undergoes medium-low temperature hot pressing treatment at a temperature of 150 ℃, preferably 140–150 ℃, a pressure of 200 MPa, preferably 190–200 MPa, and a pressing time of 10 min, preferably 8–10 min. After natural cooling, the initial sulfide solid electrolyte film is obtained.

[0061] S2. Grooves are formed on the surface of the initial dense membrane according to an array pattern to obtain a patterned electrolyte membrane.

[0062] The initial dense film is fixed on the sample stage of a laser etching machine. A fiber laser with a wavelength of 1064 nm, a power of 10 W, a scanning speed of 20 mm / s, and a repetition frequency of 20 kHz is used to etch trenches on the film surface in a regular array, preferably in a hexagonal honeycomb array. The side length of each side in the array is 300 μm, preferably 300–500 μm, and the trench width is 10 μm, preferably 8–12 μm. The trench etching depth reaches 90%–98% of the initial film thickness, preferably 90%–95%. After etching, high-purity nitrogen is used to blow away the remaining etching residue on the surface to obtain a patterned electrolyte film.

[0063] S3. Fill the groove with ion-limiting connection slurry and dry it to form ion-limiting connection;

[0064] An ion-limiting connection slurry is prepared by mass ratio of 65%–80% sulfide solid electrolyte, 15%–25% electronic insulation reinforcement material, and 5%–10% structural reinforcement adhesive. The preferred ratio is 70%–75% sulfide solid electrolyte, 18%–22% nano-Al2O3, and 6%–8% PEO (preferred). Anhydrous acetonitrile is added to the above mixed powder as a dispersant to prepare a uniform slurry with a solid content of 12–18 wt%, preferably 14–16 wt%, and a viscosity of 300–2000 mPa·s at 25 °C, preferably 500–1500 mPa·s.

[0065] The slurry is evenly applied to the surface of the patterned electrolyte membrane using a doctor blade at a speed of 2–10 mm / s, preferably 4–8 mm / s, to ensure the slurry fully covers the membrane surface and spans all grooves. The coated membrane is then placed in a reduced pressure environment at a pressure of –0.08––0.095 MPa, preferably –0.09––0.095 MPa, for 30–180 s, preferably 60–120 s, to remove air from the grooves. Subsequently, the pressure is restored to normal and allowed to stand for 10–120 s, preferably 30–60 s, to allow the synergistic effect of pressure difference and capillary force to promote the slurry to fully fill the grooves. The membrane surface is then lightly scraped with a doctor blade, elastic roller, or PTFE sheet to remove excess slurry from the surface of the transverse ion transport regions, leaving only the slurry in the grooves. The filled membrane is then placed in a vacuum drying oven and vacuum dried at room temperature for 12 h to completely remove the anhydrous acetonitrile organic solvent from the slurry.

[0066] S4. The electrolyte membrane that has been filled and dried with slurry is densified by room temperature cold pressing, then densified by medium and low temperature hot pressing, and finally cooled to room temperature to obtain a partitioned ion-controlled sulfide solid electrolyte membrane.

[0067] The electrolyte membrane, after slurry filling and drying, is placed back into the mold for room temperature cold pressing densification. The cold pressing pressure is 200-300 MPa, preferably 220-280 MPa, and the pressing time is 5-15 min, preferably 8-12 min. Subsequently, medium-low temperature hot pressing densification is performed. The hot pressing temperature is 100-150℃, preferably 120-150℃, the hot pressing pressure is 150-250 MPa, preferably 180-220 MPa, and the hot pressing time is 5-15 min, preferably 8-10 min. After hot pressing, the membrane is naturally cooled to room temperature in the furnace. After removal, a zoned ion-controlled sulfide solid electrolyte membrane is obtained.

[0068] Example 1

[0069] In this embodiment, the transverse ion transport sub-region material of the partitioned ion-controlled sulfide solid electrolyte membrane is Li6PS5Cl, and the ion current limiting connection part is a composite material of Li6PS5Cl + nano Al2O3 + PEO.

[0070] Li6PS5Cl powder with a purity ≥99.9% was mixed with 0.7 wt% PEO as a film-forming aid and toughening binder. The mixed powder was ball-milled in an inert atmosphere ball mill jar at a ball-to-powder ratio of 20:1, a rotation speed of 300 rpm, and a milling time of 15 hours to obtain a uniformly mixed electrolyte powder. The mixed powder was loaded into a mold and cold-pressed at room temperature at 200 MPa for 3 minutes to obtain an initial compacted film with a thickness of approximately 40 μm. Subsequently, hot-pressing was performed at a temperature of 150 ℃, a pressure of 200 MPa, and a time of 10 minutes, followed by natural cooling to room temperature to obtain the initial solid electrolyte membrane.

[0071] The initial film was fixed on a laser etching platform, and a fiber laser was used to perform regular array etching on the film surface to form trenches for subsequent construction of ion-limited junctions. Laser parameters: wavelength 1064 nm, power 10 W, scan speed 20 mm / s, repetition rate 20 kHz.

[0072] The array is a hexagonal honeycomb array; the hexagonal side length is 400 μm, the trench width is 10 μm, and the etching depth is 90% to 95% of the initial film thickness. After etching, it is dried with nitrogen gas to obtain a patterned electrolyte film, in which the trenches correspond to the ion current limiting connection part 2, and the non-trench area corresponds to the lateral ion transport sub-region 1.

[0073] A filler slurry for the joint was prepared by mixing 72% Li6PS5Cl, 20% nano Al2O3 (particle size about 50 nm) and 8% PEO by mass ratio, adding anhydrous acetonitrile as a dispersant, adjusting the solid content to about 15 wt%, and having a viscosity of about 800 to 1200 mPa·s at 25 °C.

[0074] The slurry is applied to the surface of the patterned electrolyte membrane and then spread laterally at a speed of 6 mm / s using a doctor blade, so that the slurry spans and covers all the grooves. The coated membrane is then placed in a reduced pressure environment (-0.09 MPa) for 90 seconds to remove air from the grooves, and then allowed to stand at normal pressure for 45 seconds to allow the slurry to fully fill the grooves under the action of pressure difference and capillary force.

[0075] The excess slurry on the surface of the transverse ion transport sub-region 1 is removed by gently scraping the membrane surface with a doctor blade or polytetrafluoroethylene sheet, leaving only the slurry in the groove; then, it is vacuum dried at room temperature for 12 hours to remove the acetonitrile solvent, resulting in a partitioned membrane with the ion current limiting connection precursor formed.

[0076] The dried partitioned membrane was placed in a mold for secondary cold pressing and densification at a pressure of 250 MPa for 10 minutes; then hot pressing and densification was performed at a temperature of 130 ℃, a pressure of 200 MPa, and a time of 8 minutes. The membrane was then cooled to room temperature in the furnace to obtain the finished partitioned ion-regulated sulfide solid electrolyte membrane with a membrane thickness controlled in the range of 40–45 μm.

[0077] In the finished membrane, the area of ​​the lateral ion transport subregion accounts for approximately 90%, and the area of ​​the connecting part accounts for approximately 10%; the thickness of the connecting part through the membrane is approximately 90%.

[0078] The negative electrode is made of lithium metal foil with a thickness of 30 μm; the positive electrode is made of NCM811 as the positive electrode active material. The mass ratio of positive electrode active material, conductive agent and binder is 90:5:5. The thickness of the positive electrode sheet is about 50 μm and the areal capacity is about 3.2 mAh / cm².

[0079] In a nitrogen glove box, the solid-state battery samples were stacked in the order of positive electrode / partitioned solid electrolyte / lithium anode. During the assembly process, a stack pressure of 10 MPa was applied and maintained to ensure tight bonding of the interfaces, thus obtaining solid-state battery samples.

[0080] The negative electrode uses lithium metal foil with a thickness of 30 μm; the positive electrode uses NCM811 as the positive electrode active material. The mass ratio of the positive electrode active material, conductive agent, and binder is 90:5:5. The thickness of the positive electrode sheet is approximately 50 μm, and the areal capacity is approximately 3.2 mAh / cm².

[0081] In a nitrogen glove box, the positive electrode, partitioned solid electrolyte, and lithium negative electrode are stacked in layers in that order. During the assembly process, a stack pressure of 10 MPa is applied and maintained to ensure that the interfaces are tightly bonded, thus obtaining a solid-state battery sample.

[0082] Example 2

[0083] The material selected for the transverse ion transport subregion is Li7P3S. 11 The ion-limiting connection part is made of Li7P3S. 11 A composite material of LiNbO3 and PVDF-HFP, wherein LiNbO3 is used to improve electronic insulation and interface stability, and PVDF-HFP is used to improve the toughness and molding stability of the ion-limiting connection.

[0084] Initial membrane preparation: Li7P3S 11 0.6 wt% PVDF-HFP was added to the powder, and an initial film with a thickness of about 35 μm was prepared according to the ball milling and cold pressing and hot pressing route of Example 1.

[0085] Trench array: A square array is used for etching, with a unit side length of about 350 μm, a trench width of 12 μm, and an etching depth of about 85% to 95% of the film thickness.

[0086] Ion-limited flow joint slurry: 75% Li7P3S by mass 11 It was prepared with 18% LiNbO3 and 7% PVDF-HFP, dispersed in anhydrous acetonitrile, with a solid content of about 14 wt% to 16 wt% and a viscosity of about 600 mPa·s to 1400 mPa·s; the filling was completed according to the route of scraping, vacuuming, standing under normal pressure, removing excess slurry from the surface, and vacuum drying as described in Example 1.

[0087] Secondary densification: cold pressing at 230 MPa for 10 min; hot pressing at 120 ℃ and 200 MPa for 10 min to obtain the finished partitioned membrane with a thickness of approximately 38 μm to 42 μm.

[0088] Example 3

[0089] Based on Example 1, this embodiment increases the penetration ratio of the ion current limiting connection to nearly 100%, for example, 95% to 98%, to further reduce the probability of rapid cross-region diffusion caused by the bottom residual connecting channel.

[0090] The key process points are: increasing the etching depth in the laser etching step while keeping the trench width constant at 8 μm to 10 μm, so that the etching depth reaches 95% to 98% of the initial film thickness; and appropriately increasing the cold pressing pressure to 280 MPa in the secondary densification process to ensure densification of the trench filling area and interface bonding. The remaining processes are the same as in Example 1.

[0091] This embodiment is more suitable for high current density or thinner electrolyte scenarios, such as electrolyte thickness of 30μm to 35μm, and can achieve better dendrite suppression and fault isolation effects.

[0092] Comparative Example 1

[0093] This comparative example is used to illustrate that, under conditions similar to the material system and densification process, if the solid electrolyte membrane is a homogeneous and continuous structure, that is, without partitioning or introducing ion-limiting connections, then when electron leakage or abnormal lithium deposition occurs in a local area, the failure is more likely to spread along the continuous low-resistance path, making it difficult to localize the fault.

[0094] Li6PS5Cl powder with a purity of ≥99.9% was mixed with 0.7 wt% PEO as a binder and toughening component. The mixture was then ball-milled in a nitrogen glove box at a ball-to-powder ratio of 20:1, a rotation speed of 300 rpm, and a ball-milling time of 15 h to obtain a uniformly mixed electrolyte powder.

[0095] The obtained powder was placed in a mold and cold-pressed at room temperature for 3 min at a pressure of 200 MPa to obtain a dense film under initial pressure. Then, hot pressing was performed at a temperature of 150 ℃, a pressure of 200 MPa, and a time of 10 min. The film was then naturally cooled to room temperature to obtain a homogeneous sulfide solid electrolyte membrane with a thickness of about 40 μm.

[0096] The difference from Example 1 is that this comparative example does not perform laser etching to form array trenches, nor does it perform a trench filling step. The resulting electrolyte membrane does not have a discrete partitioned structure of lateral ion transport subregions and ion current limiting connections in the planar direction.

[0097] The negative electrode was a 30 μm thick lithium metal foil; the positive electrode was an NCM811 positive electrode sheet (positive active material / conductive agent / binder mass ratio 90:5:5, areal capacity approximately 3.2 mAh / cm²). The electrodes were stacked in a nitrogen glove box in the order of "positive electrode / homogeneous solid electrolyte membrane / lithium negative electrode," and a stack pressure of 10 MPa was applied and maintained during assembly to ensure tight interface contact, resulting in the solid-state battery sample of Comparative Example 1.

[0098] Comparative Example 2

[0099] This comparative example is used to illustrate that if only the geometry of the trench partition is constructed, but the trench filling material does not include electronic insulation reinforcement material and toughening reinforcement system, the overall improvement of the connection in terms of electronic leakage blocking and crack blocking is insufficient, and it is difficult to achieve the synergistic effect of current limiting and insulation.

[0100] The initial dense film of Li6PS5Cl was prepared according to the steps of Example 1: 0.7 wt% PEO was added to Li6PS5Cl powder and ball-milled (ball-to-powder ratio 20:1, 300 rpm, 15 h), cold-pressed at 200 MPa for 3 min, and hot-pressed at 150 ℃ and 200 MPa for 10 min to obtain an initial film with a thickness of about 40 μm.

[0101] The initial film was fixed on a laser etching platform, and a fiber laser (wavelength 1064 nm, power 10 W, scanning speed 20 mm / s, repetition frequency 20 kHz) was used to etch a hexagonal honeycomb array to form dividing trenches: the hexagonal side length was 400 μm, the trench width was 10 μm, and the etching depth was 90% to 95% of the film thickness; after etching, the film was purged with inert gas to obtain a patterned electrolyte film.

[0102] The filler slurry for the joint consists only of Li6PS5Cl and PEO, without the addition of electronic insulating reinforcing materials such as nano-Al2O3 / LiNbO3 / Li3PO4. For example, it is mixed with 92% to 95% Li6PS5Cl and 5% to 8% PEO by mass, with anhydrous acetonitrile added as a dispersant, and the solid content is adjusted to 14 to 16 wt%. The viscosity is controlled at 500 to 1500 mPa·s at 25 ℃ to obtain a uniform slurry.

[0103] The slurry was applied to the surface of the patterned electrolyte membrane and then coated laterally at a speed of 6 mm / s using a doctor blade. The membrane was then placed under reduced pressure (-0.09 MPa) for 90 s to remove air from the trenches, and then allowed to stand at normal pressure for 45 s to promote slurry filling of the trenches. Excess slurry on the surface of the sub-regions was scraped off, leaving only the slurry in the trenches. The membrane was then vacuum dried at room temperature for 12 h to remove acetonitrile solvent, resulting in the filled partitioned membrane.

[0104] The dried partitioned membrane was placed into a mold for secondary cold pressing densification at a pressure of 250 MPa for 10 min; then hot pressing densification was performed at a temperature of 130 ℃, a pressure of 200 MPa for 8 min, and then cooled to room temperature in the furnace to obtain the electrolyte membrane of Comparative Example 2.

[0105] The difference from Example 1 is that the ion current limiting connection of Comparative Example 2 does not introduce electronic insulation reinforcement material and structural toughening reinforcement system. The connection is closer to the electrolyte path of the same material. Its ability to block electron leakage and crack propagation is relatively insufficient, and the effect of limiting cross-regional ion flux is generally weaker than that of Example 1.

[0106] The solid-state battery was assembled in the same manner as in Example 1: the negative electrode was a 30 μm lithium metal foil, the positive electrode was an NCM811 positive electrode sheet (area capacity of about 3.2 mAh / cm²), and the electrodes were stacked in the order of "positive electrode / comparative example 2 partitioned electrolyte membrane / lithium negative electrode" and a stacking pressure of 10 MPa was applied to obtain the solid-state battery sample of comparative example 2.

[0107] The ionic conductivity performance of the above embodiments or comparative examples was tested as follows: The electrolyte membrane was sandwiched between polished stainless steel blocking electrodes to form a symmetrical SS|SE|SS test structure. The effective contact area of ​​the electrodes was 1 cm², and the test environment was a constant temperature of 30°C. The AC impedance method was used for testing, with a test frequency range of 1 MHz to 0.1 Hz and an AC excitation amplitude of 5 mV. The total resistance R of the electrolyte membrane (bulk phase resistance and interfacial contact resistance) was obtained by impedance spectroscopy fitting. The room temperature ionic conductivity was calculated using the formula σ = L / (R·A), where L is the actual thickness of the electrolyte membrane and A is the effective contact area of ​​the electrodes. This test yields the effective conductivity, which includes the influence of contact, and is used for comparison between samples.

[0108] The electronic conductivity performance of the above embodiments or comparative examples was tested as follows: The same SS|SE|SS symmetrical structure as used in the ionic conductivity test was employed, with an effective electrode contact area of ​​1 cm². Constant voltage DC polarization testing was conducted at a constant temperature of 30°C. A constant DC voltage of 20 mV to 50 mV was applied, and polarization was continued for 30 to 60 minutes until the circuit current stabilized. The steady-state current value was recorded, and the electronic conductivity was calculated by combining the electrolyte membrane thickness and electrode area. If necessary, the influence of interface contact resistance on the electronic conductivity calculation results was eliminated by combining the AC impedance test results.

[0109] The critical current density test of the above embodiments or comparative examples is as follows: Assemble a Li|SE|Li symmetric battery with a lithium metal electrode thickness of 30 μm and an effective contact area of ​​1 cm² between the electrolyte membrane and the lithium electrode. The test environment is a constant temperature of 25 ℃. A stepped current ramp-up constant current charge-discharge mode is adopted, with an initial current density of 0.05 mA / cm². Each current density is maintained for a fixed time (e.g., 1 h), and the voltage is recorded. When an unrecoverable voltage drop (approaching 0), abnormal voltage fluctuation, or short circuit characteristics occur, failure is determined and the critical current density (CCD) is recorded.

[0110] The full-cell cycle and rate performance tests of the above embodiments or comparative examples are as follows: An NCM811|SE|Li all-solid-state battery was assembled with an effective electrode contact area of ​​1 cm² and a positive electrode surface capacity of 3.0 mAh / cm². The test environment was a constant temperature of 30℃. A constant current charge-discharge mode was used, with a charge-discharge voltage window of 3.0V~4.3V. Cycling tests were conducted at 0.2C and 0.5C rates, where the current density corresponding to 0.2C rate was 0.6 mA / cm², and the current density corresponding to 0.5C rate was 1.5 mA / cm². After each charge-discharge cycle, the discharge specific capacity and charge-discharge coulombic efficiency of the positive electrode were recorded. The capacity retention rate after 100 and 200 cycles was calculated. Simultaneously, the voltage difference of the charge-discharge plateau at different cycle stages was recorded to characterize the polarization trend of the battery. If the battery experienced a sudden voltage drop or a sudden capacity drop below 50% of the initial capacity, it was determined to be a battery failure, and the number of cycles and the failure mode at this time were recorded.

[0111] The electrical and mechanical properties of the samples at 30℃ are shown in the table below:

[0112] Example 1 3.2~4.2 10~18 10:1~13:1 <![CDATA[≤ 5x10 -11 ]]> 1.0~1.3 25~35 Example 2 2.8~3.8 12~20 9:1~12:1 <![CDATA[≤ 1x10 -10 ]]> 1.0~1.2 ≥ 20 Example 3 3.0~4.0 10~18 10:1~13:1 <![CDATA[≤ 5x10 -11 ]]> 1.0~1.3 25~35 Comparative Example 1 2.6~3.5 - - <![CDATA[10 -10 or higher]]> 0.7~0.9 - Comparative Example 2 2.6~3.6 25~60 3:1~6:1 <![CDATA[≥ 1x10 -10 ]]> 0.8~0.9 ≤ 15

[0113] (Table 1)

[0114] As shown in Table 1, Examples 1-3, by introducing an electronic insulation reinforcing phase and optimizing the bonding and toughening system in the ion-limiting connection, achieved an order-of-magnitude reduction in the electronic conductivity of the ion-limiting connection and an increase in fracture toughness of more than 20% compared to the sub-region material. Simultaneously, the ion conductivity of the ion-limiting connection could be controlled within 10% to 20% of that in the lateral ion transport sub-region, maintaining the confined ion connectivity and thus forming a stable current-limiting and insulation synergistic function. Comparative Example 2, although possessing the same geometric partitioning structure as Example 1, suffered from a low surface ion resistivity and insufficient electron leakage suppression capability due to the lack of an insulation reinforcing phase in the connection, making it difficult to stably achieve the design goal of fault localization. The homogeneous electrolyte membrane of Comparative Example 1 exhibited high electronic conductivity and insufficient mechanical toughness, easily becoming a weak link for lithium dendrite growth and propagation.

[0115] Li|SE|Li symmetric cells and NCM811|SE|Li full cells were assembled using the aforementioned method. Critical current density, polarization stability of the symmetric cells, and cycle stability of the full cells were tested at 30 °C. To avoid comparison bias due to differences in testing conditions, all samples used the same effective contact area and assembly stack pressure. The assembly stack pressure for both symmetric and full cells was 10 MPa. The positive electrode surface capacity of the full cells was controlled to be 3.0–3.5 mAh / cm². Representative test results—a comparison of the electrochemical performance of each sample—are shown in the table below:

[0116] Example 1 0.25~0.45 ≥300 (most samples did not experience short circuits) ≥ 80%@200 times Lithium dendrites are mostly confined within a single lateral ion transporter region, and their cross-regional expansion is significantly suppressed by the connecting parts. Example 2 0.2~0.4 ≥250 ≥75%@200 times | Dendritic growth is more dispersed, and obvious growth blockage / passivation features are observed near the junctions. Example 3 0.3~0.55 ≥350 ≥80%@200 times Electrolyte penetration probability is further reduced, and local failures are strictly limited to a few sub-regions. Comparative Example 1 0.1~0.25 50~150 ≤60%@200 times Lithium dendrites readily extend along continuous, low-resistivity pathways within the electrolyte, eventually penetrating the electrolyte layer. Comparative Example 2 0.15~0.3 120~220 55%~70%@200 times Although there is some path perturbation, dendrites may still propagate across sub-regions, resulting in unstable fault blocking effectiveness.

[0117] (Table 2)

[0118] As shown in Table 2, compared to the homogeneous sulfide solid electrolyte membrane of Comparative Example 1, the critical current density of Examples 1-3 is increased by more than 1.5 times, the stable peeling time of the symmetrical battery is extended by more than 2 times, and the capacity retention rate of the full cell after 200 cycles is increased by more than 20%, demonstrating a significant improvement in electrochemical performance and operational stability. This result proves that the discrete partition structure and functionalized ion-limiting connection designed in this invention can effectively improve the resistance to lithium dendrite formation in the solid electrolyte at the structural level, thereby extending the stable operating life of the battery.

[0119] Further comparison of Examples 1-3 with Comparative Example 2 reveals that although both employ a geometric partitioning design, the examples exhibit superior performance across all electrochemical indicators. Analysis of the parameters in Tables 1 and 2 reveals that the core reason for this difference lies in the synergistic effect of current-limiting and insulation achieved by the ion-limiting connection in Examples 1-3: a higher surface ion resistivity effectively limits ion transport across sub-regions, extremely low electronic conductivity fundamentally blocks lithium dendrite deposition caused by electron leakage, and enhanced fracture toughness effectively suppresses crack propagation and dendrite penetration, collectively achieving long-term stable suppression of lithium dendrite growth across regions. In contrast, Comparative Example 2 only creates path disturbances through geometric partitioning; lacking the functional design of an electronic insulation reinforcement phase and toughening system, it cannot achieve stable fault isolation, and the risk of dendrite expansion across regions and electrolyte penetration remains.

[0120] The disassembly and observation results of each sample further verified that... Figure 3 and Figure 4 The fault localization control mechanism shown is as follows: In the samples of Examples 1 to 3, lithium dendrites preferentially grow in local lateral ion transport sub-regions. When the dendrites grow to the ion current-limiting connection, they are limited by the low ionic conductivity, low electronic conductivity and high fracture toughness of the connection, making it difficult for them to continue to extend across regions. In the end, the failure is limited to a single sub-region or a few adjacent sub-regions, and the overall structure of the electrolyte membrane remains intact. In the homogeneous electrolyte membrane of Comparative Example 1, lithium dendrites can freely extend along continuous low-resistance pathways such as grain boundaries and pores, eventually penetrating the entire electrolyte layer and causing an internal short circuit in the battery. Although the sample of Comparative Example 2 can change the dendrite extension direction to a certain extent, due to the insufficient function of the connection, the dendrites can easily break through the zoning restrictions to achieve cross-region growth, and the fault isolation effect is unstable.

[0121] Without departing from the concept of this invention, those skilled in the art can make conventional substitutions and adjustments to the material system, array structure, and process parameters of this invention. For example, the sulfide electrolyte in the transverse ion transport region can be replaced with Li6PS5Br, the electronic insulation reinforcement material can be replaced with Li3PO4, or the array structure can be replaced with a regular octagonal array. All such substitutions should fall within the protection scope of this invention.

Claims

1. A partitioned ion-controlled sulfide solid electrolyte membrane, comprising a sheet-like membrane body being a sulfide solid electrolyte, characterized in that: A groove is formed on one side plane of the membrane body, and the groove divides the membrane body plane into several transverse ion transport sub-regions distributed in an array. An ion current limiting connection is provided in the groove to separate adjacent transverse ion transport sub-regions so that they form a restricted connection.

2. The partitioned ion-regulated sulfide solid electrolyte membrane according to claim 1, characterized in that: The thickness of the solid electrolyte membrane is 20 μm to 60 μm, and the thickness of the ion current limiting connection is 80% to 98% of the thickness of the solid electrolyte membrane.

3. The partitioned ion-regulated sulfide solid electrolyte membrane according to claim 2, characterized in that: The planar feature size of the lateral ion transport sub-region is 200μm to 800μm, and the planar area of ​​all lateral ion transport sub-regions accounts for 85% to 95% of the planar area of ​​the solid electrolyte membrane. The width of the ion current limiting connection is 5μm to 30μm, and the planar area of ​​all ion current limiting connections accounts for 5% to 15% of the planar area of ​​the solid electrolyte membrane.

4. The partitioned ion-regulated sulfide solid electrolyte membrane according to claim 3, characterized in that: At 30°C, the room temperature ionic conductivity of the transverse ion transport subregion is not less than 1 mS / cm, and the ionic conductivity of the ion current limiting connection is 5% to 25% of the ionic conductivity of the transverse ion transport subregion, while the electronic conductivity of the ion current limiting connection is not higher than 1×10⁻⁶ mS / cm. -10 The surface ion resistance ratio between the ion current limiting connection and the transverse ion transport sub-region is 8:1 to 15:1 (S / cm).

5. The partitioned ion-regulated sulfide solid electrolyte membrane according to claim 3, characterized in that: At 30°C, the fracture toughness of the ion-limiting connection is 0.7–1.5 MPa·m. 1 / 2 It also exhibits fracture toughness that is more than 20% higher than that of materials in the transverse ion transporter region.

6. The partitioned ion-regulated sulfide solid electrolyte membrane according to claim 5, characterized in that: The composite material used in the ion-limiting connection is composed of the following components by mass percentage: Sulfide solid electrolyte, 65%–80%; Electronic insulation reinforcement material, 15%–25%; Structural reinforcing adhesive, 5%–10%; The sum of the mass percentages of all components is 100%.

7. The partitioned ion-regulated sulfide solid electrolyte membrane according to claim 6, characterized in that: The electronic insulation reinforcement material adopts at least one of Al2O3, LiNbO3 and Li3PO4, and the particle size of the electronic insulation reinforcement material is 20nm to 200nm.

8. A solid-state battery using the partitioned ion-regulated sulfide solid electrolyte membrane according to any one of claims 1 to 7, characterized in that: The membrane includes a positive electrode, a negative electrode, and the partitioned ion-regulated sulfide solid electrolyte membrane located between the positive and negative electrodes.

9. The solid-state battery according to claim 8, characterized in that: The positive electrode comprises a positive electrode active material, a conductive agent, and a binder, wherein the positive electrode active material is at least one of layered oxide, spinel oxide, olivine phosphate, and sulfur positive electrode material.

10. A method for preparing the partitioned ion-regulated sulfide solid electrolyte membrane according to claim 1, characterized in that: Perform the following steps in a high-purity nitrogen atmosphere: S1. Preparation of an initial dense membrane for a sulfide solid electrolyte; S2. Grooves are formed on the surface of the initial dense membrane according to an array pattern to obtain a patterned electrolyte membrane; S3. Fill the groove with ion-limiting connection slurry and dry it to form ion-limiting connection; S4. The electrolyte membrane that has been filled and dried with slurry is densified by room temperature cold pressing, then densified by medium and low temperature hot pressing, and finally cooled to room temperature to obtain a partitioned ion-controlled sulfide solid electrolyte membrane.

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