High-voltage positive electrode sheet component with in-situ formed stabilizing interfacial layer and applications thereof

Abstract

This application relates to the field of all-solid-state battery technology, and discloses a high-voltage cathode composition with an in-situ formed stabilizing interface layer and its application. The cathode composition includes 75% nickel-rich layered oxide cathode active material particles with a median particle size of 5 μm, 20% Argyrodite-type sulfide solid electrolyte powder with a median particle size of 2 μm, 3% carbon black, and 2% styrene-butadiene rubber. An interface stabilizing layer composed of lithium, phosphorus, oxygen, and sulfur is present at the contact interface between the nickel-rich layered oxide cathode active material particles and the sulfide solid electrolyte powder. The preparation method includes coating and drying a slurry to obtain a dry cathode electrode, applying static mechanical pressure to the dry cathode electrode and heating it for thermo-pressure coupling isothermal holding treatment, cooling and unloading the pressure to generate the interface stabilizing layer in situ. This invention blocks side reactions at the cathode contact interface, reduces solid-phase contact impedance, and improves the cycle life of all-solid-state batteries.

Description

Technical Field

[0001] This invention relates to the field of all-solid-state battery technology, specifically to high-voltage cathode components with in-situ formed stabilization interface layers and their applications. Background Technology

[0002] All-solid-state batteries use solid electrolytes instead of traditional liquid electrolytes, improving battery safety. Among them, sulfide solid electrolytes, with their high room-temperature ionic conductivity and good material ductility, represent an important development direction in the field of all-solid-state batteries. To improve the energy density of all-solid-state batteries, high-capacity nickel-rich layered oxides are typically used as the positive electrode active material.

[0003] However, there is an electrochemical incompatibility issue between nickel-rich layered oxide cathodes and sulfide solid electrolytes. When the battery is charged to a high operating voltage, side reactions occur at the physical interface between the cathode active material and the sulfide solid electrolyte. Transition metal elements in the cathode material cross-diffusion with elements such as sulfur and phosphorus in the solid electrolyte, generating insulating byproducts with low ionic conductivity, inducing a space charge layer effect, and leading to an increase in the contact impedance at the cathode interface.

[0004] Meanwhile, solid-state batteries rely on mechanical compaction to form solid-solid physical contacts. During charge-discharge cycles, the nickel-rich layered oxide cathode material undergoes lattice volume expansion and contraction. This periodic volume change disrupts the initial contact state between the cathode particles and electrolyte particles, leading to gaps and microcracks within the material. The reduction in the solid-solid physical contact area cuts off the ion conduction pathways within the battery, causing capacity decay in all-solid-state batteries.

[0005] Existing technologies typically involve pre-preparing an oxide coating layer on the surface of the positive electrode active material to isolate the positive electrode from the electrolyte. This ex-situ coating method requires processes such as precursor coating and high-temperature calcination, making the preparation process complex. Furthermore, conventional room-temperature pressing processes can only achieve physical adhesion between particle surfaces, failing to establish a strong chemical bond between heterogeneous particles. After multiple cycles and volumetric deformations, the solid-phase contact interface is prone to separation, making it impossible to maintain the integrity and stability of the internal structure of the positive electrode in the long term. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a high-voltage cathode material composition with an in-situ formed stable interface layer and its application. This solves the problem that nickel-rich layered oxide cathodes and sulfide solid electrolytes in existing all-solid-state batteries are prone to interfacial side reactions and physical contact failures during charge-discharge cycles. Traditional ex-situ coating and room temperature pressing processes cannot establish a strong chemical bond between particles, leading to increased battery interface impedance and capacity decay.

[0007] To achieve the above objectives, the present invention provides a high-voltage positive electrode composition having an in-situ formed stabilization interface layer, employing the following technical solution:

[0008] The high-voltage cathode material having an in-situ formed stable interface layer comprises, by weight percentage, the following raw materials:

[0009] 70% to 85% of nickel-rich layered oxide positive electrode active material particles with a median particle size of 3 μm to 8 μm, 10% to 25% of Argyrodite-type sulfide solid electrolyte powder with a median particle size of 1 μm to 3 μm, 1% to 5% of carbon black and 1% to 5% of styrene-butadiene rubber.

[0010] The interface between the nickel-rich layered oxide positive electrode active material particles and the Argyrodite-type sulfide solid electrolyte powder has an interface stabilizing layer composed of lithium, phosphorus, oxygen and sulfur elements.

[0011] By adopting the above technical solution, a nickel-rich layered oxide with a median particle size of 3μm to 8μm is used in combination with a sulfide solid electrolyte with a median particle size of 1μm to 3μm, and an interface stabilizing layer composed of lithium, phosphorus, oxygen and sulfur is generated in situ at the solid phase contact site. Therefore, the effect of blocking interface side reactions and reducing contact resistance is achieved.

[0012] The generation mechanism and function of the interface stabilization layer are explained step by step:

[0013] In the first stage, solid electrolyte powder with a median particle size of 1 μm to 3 μm is filled in the gaps between nickel-rich layered oxide positive electrode active material particles with a median particle size of 3 μm to 8 μm through particle gradation of different particle sizes, thus establishing a continuous ion conduction network.

[0014] In the second stage, under the coupled action of heating and mechanical pressure, the oxygen released from the nickel-rich layered oxide surface reacts chemically with the Argyrodite-type sulfide solid electrolyte.

[0015] The aforementioned in-situ generated interface stabilizing layer forms a physical isolation structure between the positive electrode active material and the sulfide bulk material, avoiding the space charge layer effect during charge-discharge cycles, suppressing cross-diffusion of elements, and controlling the increase in impedance at the solid-phase contact interface.

[0016] Preferably, the thickness of the interface stabilizing layer composed of lithium, phosphorus, oxygen and sulfur does not exceed 100 nm.

[0017] By adopting the above technical solution, the thickness of the interface stabilization layer is limited to no more than 100nm, which can play a physical isolation role while avoiding the increase of lithium-ion conduction resistance by an excessively thick inactive layer and maintaining the ionic conductivity of the positive electrode components.

[0018] Preferably, the high-voltage cathode material having an in-situ formed stabilizing interface layer is obtained by the following preparation method:

[0019] In an argon atmosphere glove box, nickel-rich layered oxide positive electrode active material particles, Argyrodite type sulfide solid electrolyte powder and carbon black are weighed and placed in a mixing tank for mechanical stirring and dry mixing to obtain dry mixed powder.

[0020] Styrene-butadiene rubber was dissolved in anhydrous toluene to prepare a slurry. The slurry was then added to dry-mixed powder in batches for dispersion treatment to obtain a composite slurry for the positive electrode of an all-solid-state battery.

[0021] The all-solid-state battery positive electrode composite slurry was coated onto an aluminum foil current collector that had undergone surface carbon coating treatment, and then vacuum dried to remove anhydrous toluene solvent, resulting in a dry positive electrode sheet.

[0022] The positive electrode drying sheet is placed in a flat plate hot press, and static mechanical pressure is applied to the vertical surface of the positive electrode drying sheet. While maintaining the static mechanical pressure, the heating program is started to raise the temperature. The temperature and pressure are maintained under thermo-pressurization coupling. The heating program is turned off, and the temperature is allowed to drop naturally while maintaining the static mechanical pressure. The static mechanical pressure is then unloaded, and an interface stabilizing layer composed of lithium, phosphorus, oxygen and sulfur is generated in situ at the interface between the nickel-rich layered oxide positive electrode active material particles and the Argyrodite-type sulfide solid electrolyte powder.

[0023] By adopting the above technical solution, the use of static mechanical pressure combined with programmed temperature rise thermo-pressure coupling process provides thermal energy and mechanical pressure, improving the problem of poor contact between solid particles at room temperature, thus obtaining a tightly bonded in-situ bonding interface effect.

[0024] The in-situ coupling mechanism of this preparation method is explained step by step:

[0025] In the first stage, static mechanical pressure compresses the pores inside the drying electrode, causing the powder particles to deform and increasing the physical contact area between the particles.

[0026] In the second stage, under heating conditions, an in-situ chemical reaction occurs at the contact interface region, forming a molecular-level bonding layer.

[0027] In the third stage, the temperature is naturally reduced while maintaining pressure to avoid microcracks at the interface caused by differences in thermal expansion and contraction coefficients, thus maintaining the structural integrity of the positive electrode components.

[0028] Preferably, mechanical stirring and dry mixing are carried out in an argon atmosphere glove box with a dew point below -40°C and a water and oxygen content of less than 0.1 ppm for 1 hour.

[0029] By adopting the above technical solutions, the water and oxygen content of the operating environment is controlled, preventing the hydrolysis reaction of sulfide solid electrolytes caused by environmental moisture. Mechanical dry mixing creates a mixed contact structure between powder particles.

[0030] Preferably, when the adhesive is added to the dry-mixed powder in batches for dispersion treatment, the final solid content of the all-solid-state battery cathode composite slurry is controlled to be 65%, and it is dispersed for 2 hours at a speed of 2000 rpm using a high-shear homogenizer.

[0031] By employing the above technical solution, batch-wise adhesive addition and high-shear homogenization can break the agglomeration of carbon black powder, allowing the binder to coat the surface of the solid components. Controlling the solid content to 65% and dispersing for 2 hours yields a slurry with good flowability and suspension stability, preventing particle sedimentation.

[0032] Preferably, a blade coater is used to coat the all-solid-state battery positive electrode composite slurry onto an aluminum foil current collector that has undergone surface carbon coating treatment to form a wet film coating. The thickness of the wet film coating is controlled to be 100 μm, and the coating is vacuum dried at 100°C for 12 hours to remove anhydrous toluene solvent.

[0033] By adopting the above technical solution, the aluminum foil current collector treated with surface carbon coating has reduced interfacial contact resistance and improved slurry wettability. Vacuum drying at 100℃ for 12 hours can remove residual anhydrous toluene solvent in the system, avoiding interference of residual solvent on the electrochemical performance of the all-solid-state battery.

[0034] Preferably, a static mechanical pressure of 10 MPa to 100 MPa is applied to the vertical surface of the positive electrode drying sheet. While maintaining the static mechanical pressure, the temperature of the template of the flatbed hot press is raised to 100°C to 250°C. The sheet is then subjected to constant temperature and pressure treatment under hot-press coupling for 0.5 to 5 hours, and then naturally cooled to 25°C while maintaining the static mechanical pressure.

[0035] By adopting the above technical solution, the defined temperature, pressure, and time parameters provide the reaction conditions for in-situ generation of a stable interface layer. Pressures below 10 MPa are insufficient to eliminate porosity, while pressures above 100 MPa easily lead to the fragmentation of active material particles; temperatures below 100°C result in a slow reaction that is difficult to generate an interface layer, while temperatures above 250°C easily lead to the decomposition of sulfides; this isothermal holding time range allows for control of the interface layer thickness.

[0036] Preferably, the static mechanical pressure is 10MPa to 50MPa, the temperature of the template of the flatbed hot press is raised to 100℃ to 150℃, and the constant temperature and pressure holding time is 0.5 hours to 2.5 hours.

[0037] By adopting the above technical solution, lower mechanical pressure and heating temperature are used, which is suitable for cathode material systems with high interfacial reactivity. This can reduce process energy consumption and avoid excessive growth of the interfacial layer.

[0038] Preferably, the static mechanical pressure is 50MPa to 100MPa, the temperature of the template of the flatbed hot press is raised to 150℃ to 250℃, and the constant temperature and pressure holding time is 2.5 hours to 5 hours.

[0039] By adopting the above technical solution, using higher mechanical pressure and heating temperature, it is possible to accelerate atomic diffusion at the solid interface, improve the interface contact strength, and enhance the stability of the internal structure.

[0040] Secondly, the present invention provides the application of a high-voltage cathode component with an in-situ formed stabilizing interface layer in the preparation of all-solid-state batteries, employing the following technical solution:

[0041] Application of high-voltage cathode components with in-situ formed stabilization interface layers in the preparation of all-solid-state batteries.

[0042] By adopting the above technical solution, and using the aforementioned cathode components to prepare all-solid-state batteries, the cycle life is improved and the operational stability of the all-solid-state batteries is maintained. The in-situ generated interface stabilizing layer serves as both the lithium-ion conducting phase and the electronic insulating phase, forming physical isolation at the contact interface, reducing the increase in battery internal resistance during charge-discharge cycles, and improving the capacity retention rate of the all-solid-state battery under high-voltage conditions.

[0043] This invention provides a high-voltage cathode composition with an in-situ formed stabilized interface layer and its application. It offers the following advantages:

[0044] 1. This invention employs a graded mixture of nickel-rich layered oxide with a median particle size of 5 μm and sulfide solid electrolyte with a median particle size of 2 μm, and generates an interface stabilizing layer with a thickness not exceeding 100 nm in situ at the solid-phase contact interface between the two, thus forming a physical isolation between the positive electrode active material and the sulfide material. This structure can block interfacial side reactions during battery charge-discharge cycles and suppress cross-diffusion of elements between different components, thereby controlling and reducing the impedance of the positive electrode contact interface.

[0045] 2. The preparation method of the present invention adopts a static mechanical pressure combined with a programmed temperature rise thermo-pressure coupling process, applying a pressure of 10MPa to 100MPa and a temperature of 100°C to 250°C to the positive electrode sheet. This step can compress the internal pores of the electrode sheet to increase the physical contact area between powder particles, while providing heat energy to promote a chemical reaction at the contact interface to form a bonding layer. In the subsequent pressure holding and cooling process, it avoids the formation of microcracks in the material due to the difference in thermal expansion and contraction, thus ensuring the integrity of the internal structure of the positive electrode sheet.

[0046] 3. This invention applies the above-mentioned positive electrode components to the preparation of all-solid-state batteries. The in-situ generated interface stabilizing layer serves as both the lithium-ion conducting phase and the electronic insulating phase, constructing an electrochemical isolation structure inside the positive electrode. This structure limits the increase in internal resistance of the battery under high operating voltage conditions, slows down the capacity decay of the all-solid-state battery during long-term charge-discharge cycles, and improves the cycle life and capacity retention of the battery. Attached Figure Description

[0047] Figure 1 The initial AC impedance Nyquist plots for the all-solid-state batteries in Examples 1-3 are shown.

[0048] Figure 2 The bar chart shows the comparison of the positive electrode interface reaction resistance in Examples 1-3.

[0049] Figure 3 Linear scan current-voltage curves of all-solid-state batteries in Examples 1-3;

[0050] Figure 4 This is a bar chart comparing the high-potential oxidation leakage current density of Examples 1-3;

[0051] Figure 5 The graphs show the cycle life curves of the all-solid-state batteries of Examples 1-3 and Comparative Examples 1-4 at a high cutoff voltage of 4.3V after 500 cycles.

[0052] Figure 6 The bar chart shows the capacity retention rate of all-solid-state batteries in Examples 1-3 and Comparative Examples 1-4 after 500 cycles at 4.3V.

[0053] Figure 7 This is a multi-gradient rate discharge cycle curve;

[0054] Figure 8 A bar chart comparing specific capacity at various discharge rates. Detailed Implementation

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, preparation examples, embodiments, comparative examples, and test examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Examples 1-3:

[0057] Example 1:

[0058] This embodiment provides a high-voltage cathode material composition with an in-situ formed stable interface layer and its application, including the following steps:

[0059] S1. Raw material weighing and dry mixing:

[0060] In an argon atmosphere glove box with a dew point below -40℃ and a water and oxygen content of less than 0.1ppm, the raw materials were weighed according to the total solid mass percentage (%): 75% nickel-rich layered oxide positive electrode active material ( (Particle size D50 is 5μm), 20% Argyrodite type sulfide solid electrolyte powder ( The powder consists of 2 μm of solid electrolyte and 3% of conductive additive (SuperP carbon black). The powder is placed in a mixing tank and mechanically stirred for 1 hour to ensure that the solid electrolyte and conductive additive are uniformly adhered to the surface of the positive electrode active material particles.

[0061] S2. Preparation of positive electrode composite slurry:

[0062] Styrene-butadiene rubber (SBR) was weighed at a ratio of 2% as a polymeric binder and completely dissolved in an appropriate amount of anhydrous toluene solvent to prepare a homogeneous adhesive solution. Subsequently, this adhesive solution was slowly added in batches to the dry-mixed powder obtained in step S1, controlling the final solid content of the system to be 65%. The mixture was then dispersed using a high-shear homogenizer at 2000 rpm for 2 hours to obtain a uniformly dispersed all-solid-state battery cathode composite slurry.

[0063] S3. Electrode coating and drying:

[0064] Using a doctor blade coater, the above-mentioned positive electrode composite slurry was uniformly coated onto an aluminum foil current collector that had undergone surface carbon coating treatment, controlling the wet film coating thickness to be approximately 100 μm. After coating, the electrode was transferred into a vacuum drying oven and vacuum dried at 100°C for 12 hours to completely evaporate and remove the anhydrous toluene solvent in the system, obtaining a pre-formed dry positive electrode.

[0065] S4. In-situ thermomechanical induction of the stabilized interface layer:

[0066] The dried positive electrode sheet obtained in step S3 was placed in a high-precision flatbed hot press inside a glove box for in-situ interface forming. First, a static mechanical pressure of 10 MPa was applied to the vertical surface of the electrode sheet. While maintaining this pressure, the heating program was started, raising the temperature of the hot press template to 100°C. The electrode sheet was then held at a constant temperature and pressure (10 MPa, 100°C) for 0.5 hours under hot-press coupling. After processing, the heating program was turned off, allowing the electrode sheet to cool naturally to room temperature (25°C) while maintaining a pressure of 10 MPa. Finally, the pressure was released.

[0067] After the above steps, an extremely thin interface stabilizing layer mainly composed of LixPOySz is generated in situ at the interface between the positive electrode active material particles and the sulfide solid electrolyte, thus obtaining the high-voltage positive electrode sheet for all-solid-state batteries of the present invention.

[0068] Example 2:

[0069] This embodiment provides a high-voltage cathode material composition with an in-situ formed stable interface layer and its application, including the following steps:

[0070] S1. Raw material weighing and dry mixing:

[0071] In an argon atmosphere glove box with a dew point below -40℃ and a water and oxygen content of less than 0.1ppm, the raw materials were weighed according to the total solid mass percentage (%): 75% nickel-rich layered oxide positive electrode active material ( (Particle size D50 is 5μm), 20% Argyrodite type sulfide solid electrolyte powder ( The powder consists of 2 μm of solid electrolyte and 3% of conductive additive (SuperP carbon black). The powder is placed in a mixing tank and mechanically stirred for 1 hour to ensure that the solid electrolyte and conductive additive are uniformly adhered to the surface of the positive electrode active material particles.

[0072] S2. Preparation of positive electrode composite slurry:

[0073] Styrene-butadiene rubber (SBR) was weighed at a ratio of 2% as a polymeric binder and completely dissolved in an appropriate amount of anhydrous toluene solvent to prepare a homogeneous adhesive solution. Subsequently, this adhesive solution was slowly added in batches to the dry-mixed powder obtained in step S1, controlling the final solid content of the system to be 65%. The mixture was then dispersed using a high-shear homogenizer at 2000 rpm for 2 hours to obtain a uniformly dispersed all-solid-state battery cathode composite slurry.

[0074] S3. Electrode coating and drying:

[0075] Using a doctor blade coater, the above-mentioned positive electrode composite slurry was uniformly coated onto an aluminum foil current collector that had undergone surface carbon coating treatment, controlling the wet film coating thickness to be approximately 100 μm. After coating, the electrode was transferred into a vacuum drying oven and vacuum dried at 100°C for 12 hours to completely evaporate and remove the anhydrous toluene solvent in the system, obtaining a pre-formed dry positive electrode.

[0076] S4. In-situ thermomechanical induction of the stabilized interface layer:

[0077] The dried positive electrode sheet obtained in step S3 was placed in a high-precision flatbed hot press inside a glove box for in-situ interface forming. First, a static mechanical pressure of 50 MPa was applied to the vertical surface of the electrode sheet. While maintaining this pressure, the heating program was started, raising the temperature of the hot press template to 150°C. The electrode sheet was then held at a constant temperature and pressure (50 MPa, 150°C) for 2.5 hours under hot-press coupling. After processing, the heating program was turned off, allowing the electrode sheet to cool naturally to room temperature (25°C) while maintaining a pressure of 50 MPa. Finally, the pressure was released.

[0078] After the above steps, an extremely thin interface stabilizing layer with moderate thickness, mainly composed of LixPOySz, is generated in situ at the interface between the positive electrode active material particles and the sulfide solid electrolyte, thus obtaining the high-voltage positive electrode sheet for all-solid-state batteries of the present invention.

[0079] Example 3:

[0080] This embodiment provides a high-voltage cathode material composition with an in-situ formed stable interface layer and its application, including the following steps:

[0081] S1. Raw material weighing and dry mixing:

[0082] In an argon atmosphere glove box with a dew point below -40℃ and a water and oxygen content of less than 0.1ppm, the raw materials were weighed according to the total solid mass percentage (%): 75% nickel-rich layered oxide positive electrode active material ( (Particle size D50 is 5μm), 20% Argyrodite type sulfide solid electrolyte powder ( The powder consists of 2 μm of solid electrolyte and 3% of conductive additive (SuperP carbon black). The powder is placed in a mixing tank and mechanically stirred for 1 hour to ensure that the solid electrolyte and conductive additive are uniformly adhered to the surface of the positive electrode active material particles.

[0083] S2. Preparation of positive electrode composite slurry:

[0084] Styrene-butadiene rubber (SBR) was weighed at a ratio of 2% as a polymeric binder and completely dissolved in an appropriate amount of anhydrous toluene solvent to prepare a homogeneous adhesive solution. Subsequently, this adhesive solution was slowly added in batches to the dry-mixed powder obtained in step S1, controlling the final solid content of the system to be 65%. The mixture was then dispersed using a high-shear homogenizer at 2000 rpm for 2 hours to obtain a uniformly dispersed all-solid-state battery cathode composite slurry.

[0085] S3. Electrode coating and drying:

[0086] Using a doctor blade coater, the above-mentioned positive electrode composite slurry was uniformly coated onto an aluminum foil current collector that had undergone surface carbon coating treatment, controlling the wet film coating thickness to be approximately 100 μm. After coating, the electrode was transferred into a vacuum drying oven and vacuum dried at 100°C for 12 hours to completely evaporate and remove the anhydrous toluene solvent in the system, obtaining a pre-formed dry positive electrode.

[0087] S4. In-situ thermomechanical induction of the stabilized interface layer:

[0088] The dried positive electrode sheet obtained in step S3 was placed in a high-precision flatbed hot press inside a glove box for in-situ interface forming. First, a static mechanical pressure of 100 MPa was applied to the vertical surface of the electrode sheet. While maintaining this pressure, a heating program was started, raising the temperature of the hot press template to 250°C. Under this hot-press coupling state (100 MPa, 250°C), the electrode sheet was held at this constant temperature and pressure for 5 hours. After processing, the heating program was turned off, allowing the electrode sheet to cool naturally to room temperature (25°C) while maintaining a pressure of 100 MPa. Finally, the pressure was released.

[0089] After the above steps, an extremely thin interface stabilizing layer, mainly composed of LixPOySz and with a thickness close to the upper limit (i.e. close to 100 nm), is generated in situ at the interface between the positive electrode active material particles and the sulfide solid electrolyte, thus obtaining the high-voltage positive electrode sheet for all-solid-state batteries of the present invention.

[0090] Comparative Examples 1-4:

[0091] Comparative Example 1:

[0092] Compared to Example 2, the difference is that in step S4, the positive electrode is not heated; instead, a conventional molding pressure of 5 MPa is applied at room temperature (25°C) and held for 2.5 hours. All other aspects remain the same.

[0093] Comparative Example 2:

[0094] Compared with Example 2, the difference is that in step S4, the heat treatment temperature is set to 300°C, and the pressure is maintained at 50 MPa for 2.5 hours. All other aspects are the same.

[0095] Comparative Example 3:

[0096] The difference from Example 2 is that in step S4, an ultra-high mechanical pressure of 300 MPa is applied, and the pressure is maintained at a constant temperature of 150°C for 2.5 hours. All other aspects are the same.

[0097] Comparative Example 4:

[0098] The difference compared to Example 2 is that in step S1, a pre-processed... Artificial surface coating treatment The positive electrode material replaces the untreated raw powder; and in step S4, the positive electrode sheet is not heated, but only a conventional molding pressure of 5 MPa is applied at room temperature (25°C). Everything else is the same.

[0099] Test Examples 1-4:

[0100] Test Example 1: Initial AC Impedance Test of All-Solid-State Battery

[0101] In an argon atmosphere glove box, the high-voltage positive electrode sheets prepared in Examples 1, 2 and 3 were cut into circular pieces with a diameter of 10 mm using a punching machine to serve as working electrodes.

[0102] Weigh out 100mg The powder was placed in an insulating mold with an inner diameter of 10 mm and cold-pressed under a pressure of 200 MPa to obtain a solid electrolyte isolation layer with a thickness of about 0.8 mm.

[0103] The cut positive electrode sheet is attached to one side of the solid electrolyte layer, and a 10mm diameter Li-In alloy foil is attached to the opposite side as the counter electrode and reference electrode.

[0104] The multi-layer structure described above is assembled into a solid-state button test mold. A constant contact pressure of 250N is applied to the mold using a torque wrench, and the mold is hermetically sealed to complete the assembly of the test battery.

[0105] The assembled all-solid-state test battery was moved into a high and low temperature alternating test chamber, the ambient temperature was set to 25°C, and it was left to stand for 4 hours to allow the internal system of the battery to reach a thermodynamically stable state.

[0106] Connect the positive and negative terminals of the battery to the electrochemical workstation. Apply an AC perturbation signal under open-circuit voltage (OCV) conditions, setting the AC voltage amplitude to 10mV and the frequency scan range to 1MHz to 10mHz.

[0107] Impedance spectrum data were collected, and the corresponding equivalent circuit model was applied using ZView software.

[0108] ( A nonlinear least-squares fit was performed on the Nyquist plot. The impedance value corresponding to the semicircular arc in the mid-frequency region was read and multiplied by the actual geometric area of ​​the positive electrode plate ( ). The positive electrode interface reaction resistance was calculated.

[0109] Table 1. Initial AC impedance test data of all-solid-state batteries in Examples 1-3 at 25°C

[0110]

[0111] in conclusion:

[0112] Combining the data in Table 1 and Figure 1 Histograms of initial AC impedance distribution of all-solid-state batteries in Examples 1-3 Figure 2 The positive electrode interface reaction resistance was analyzed by comparing the bar charts. Figure 1 The initial resistance distribution of cathode sheets from Examples 1, 2, and 3, prepared using different parameters (pressure and temperature coupling conditions), was measured at 25°C after being assembled into all-solid-state batteries. The dark gray bars represent the bulk resistance of the battery. The light gray columns represent the interfacial resistance between the positive electrode active material and the solid electrolyte. The specific values ​​(unit: ) are precisely marked above the columns in the diagram. The results clearly show that the bulk resistance of the three embodiments remained essentially constant. This comparison intuitively confirms that the in-situ thermomechanical induction molding process effectively reduces the interfacial impedance without damaging the electrolyte bulk structure.

[0113] Figure 2 Extracted Figure 1 The positive electrode interface reaction resistance after Nyquist plot fitting with equivalent circuit ( The specific values ​​are shown in the bar chart, where the height of the bars represents the resistance value. Figure 2 Visually, the initial interfacial reaction resistance of Examples 1, 2, and 3 were all successfully controlled within a certain range. Below the set threshold. This indicates that under the coupled conditions of pressure from 10 MPa to 100 MPa and temperature from 100 °C to 250 °C, restricted interfacial atomic interdiffusion occurred at the interface between the positive electrode active material and the solid electrolyte.

[0114] Among them, Example 2, which uses moderate thermomechanical coupling, exhibits the lowest interfacial impedance, with its interfacial reaction resistance decreasing to [missing value]. This confirms that the process parameters, while ensuring the density of physical contact, also formed an in-situ interface stabilization layer with an optimal lithium-ion conduction network. This indicates that the thermomechanical conditions of 50 MPa and 150 °C provided suitable activation energy, enabling the LixPOySz composite layer formed by the combination of lattice oxygen with phosphorus and sulfur to possess the richest grain boundary defects and free volume, thus constructing a continuous lithium-ion transport channel.

[0115] The resistance in Example 3 rose back to This reflects that further increases in temperature and pressure propelled the reaction deeper, with the physical thickness of the stabilizing layer approaching the upper limit of 100 nm. The elongation of the ion migration path led to an increase in ohmic voltage drop, but it remained within the allowable conductivity range. The thermodynamic energy under the conditions of Example 1 was lower, and the interface layer thickness was thinner and close to the lower limit of 1 nm. The resistance mainly comes from the boundary effect of the physical contact density.

[0116] The test results, from the perspective of macroscopic electrochemical kinetics, confirm that the amorphous or nanocrystalline composite layer generated in situ by the process of this invention, while establishing a chemical passivation barrier, does not block the rapid migration network of solid ions due to component evolution, thus meeting the structural design requirements of low initial internal resistance and high output characteristics of all-solid-state batteries.

[0117] Test Example 2: High Voltage Linear Scan Volt-Ampere (LSV) or DC Leakage Current Test

[0118] Test objective: To verify whether the in-situ generated LixPOySz composite layer possesses an electrochemical window broadening effect and a chemical passivation barrier function (i.e., the high-voltage non-decomposition mentioned in the mechanism). Test subjects: Battery systems assembled in Examples 1, 2, and 3.

[0119] In an argon atmosphere glove box, using an insulating mold with an inner diameter of 10 mm, 100 mg of... The powder was cold-pressed under a pressure of 200 MPa to prepare a solid electrolyte isolation layer.

[0120] The positive electrode sheets prepared in Examples 1, 2 and 3 were cut into circular pieces with a diameter of 10 mm and attached to one side of the above-mentioned solid electrolyte isolation layer.

[0121] A 10mm diameter lithium foil was attached to the opposite side of the solid electrolyte isolation layer to serve as the counter electrode and reference electrode, thus assembling a test system with a half-cell structure.

[0122] The assembled battery system was placed in a high-precision test mold, a contact pressure of 250N was applied, and the mold was sealed. The test mold was then placed in a high and low temperature alternating test chamber set at 25℃ and left to stand for 4 hours to allow the system to reach thermodynamic equilibrium.

[0123] Connect the battery system to the electrochemical workstation. Set the test mode to linear sweep voltammetry (LSV). Set the scan start potential to the battery's open-circuit voltage (OCV) and the scan end potential to 5.0V. ).

[0124] To record the weak Faraday oxidation side reaction current at the interface, the scan rate was set to 0.1 mV / s. Potential and response current data were acquired in real time during the test, and the results were analyzed based on the geometric area of ​​the positive electrode (…). Convert the response current to current density. ).

[0125] Table 2. High-potential oxidation leakage current density data of all-solid-state batteries at 25°C using linear scan voltammetry testing.

[0126]

[0127] in conclusion:

[0128] Combining the data in Table 2 and Figure 3 Linear scan voltammetry (LSV) curve, Figure 4 The leakage current density of high-potential nodes was analyzed by comparing histograms.

[0129] Figure 3 This demonstrates how to slowly scan the battery voltage from an open-circuit state to 5.0V. The current response changes during the process are shown. The horizontal axis represents the scanning potential, and the vertical axis represents the oxidation leakage current density. The solid line, dashed line, and dotted line represent Examples 1, 2, and 3, respectively. The curves and data in Table 2 show that the oxidation side reaction current in all three examples was effectively suppressed to the microampere level in the high potential range above 4.3V. Conventional untreated sulfide solid electrolytes typically undergo severe oxidation and generate a large current at 3.0V, and generate oxidation side reaction currents in the hundreds of microamperes above 4.3V. This result directly reflects the antioxidant decomposition ability of the in-situ stabilizing layer under a high electric field, confirming that the LixPOySz composite layer induced by the in-situ thermomechanical process establishes a chemical passivation barrier between the positive electrode active material and the sulfide solid electrolyte.

[0130] The broadening of the electrochemical window stems from changes in the electronic band structure of the composite layer components. After the lattice oxygen on the cathode material surface participates in interfacial reconstruction, the electronegativity of oxygen is higher than that of sulfur, and the introduction of oxygen atoms lowers the highest occupied molecular orbital (HOMO) energy level of the interfacial layer material. This lower HOMO energy level allows the LixPOySz composite layer to withstand high potential environments of 4.5V or even 4.8V without electron gain / loss or structural disintegration. This in-situ layer physically blocks the direct contact between the unreacted sulfide electrolyte and the high-potential cathode surface, cutting off the reaction pathway for the continuous oxidation of sulfides.

[0131] Figure 4 Extracted Figure 3 Quantitative comparisons were made of specific leakage current densities at three specific high potentials: 4.3V, 4.5V, and 4.8V. Light gray, medium gray, and dark gray bars correspond to Examples 1, 2, and 3, respectively. The bar chart clearly shows that the leakage current density of each example at the extreme high voltage (4.8V) is lower than... Among them, Example 2, which uses moderate thermomechanical parameters for induced molding, exhibits the lowest leakage current response at all voltage nodes (only at 4.5V). The results confirm that the generated LixPOySz composite layer possesses optimal chemical density and electrochemical passivation barrier function, minimizing electron tunneling effects and localized direct contact caused by interfacial micropores.

[0132] Example 1 shows that the current density at 4.8V increases to This indicates that the thickness of the interface layer generated under low pressure and temperature conditions is close to the lower limit of 1 nm, and weak electron tunneling leakage exists under high electric field. The current density in Example 3 at 4.8V is... The increased reaction depth led to a stable layer thickness approaching the 100nm upper limit, and the stress accumulation in the local phase structure resulted in trace structural defects, causing the current response to be slightly higher than in Example 2. Macroscopic electrochemical test data showed that the in-situ generated amorphous or nanocrystalline LixPOySz composite layer possessed an electrochemical window broadening effect, meeting the interface stability requirements of all-solid-state batteries under high-voltage conditions.

[0133] Test Example 3: Long Cycle Life Test at 4.3V High Cutoff Voltage

[0134] Inside an argon-atmospheric glove box, the positive electrode sheets prepared in Examples 1-3 and Comparative Examples 1-4 were respectively mixed with... The solid electrolyte layer and the lithium metal foil negative electrode are assembled into an all-solid-state test battery.

[0135] The sealed all-solid-state test battery was placed in a constant temperature test chamber at 25°C and left to stand for 12 hours.

[0136] Connect the battery to the battery charge / discharge test system and set the test potential window to 2.8V to 4.3V. ).

[0137] The charge / discharge rate is set to 0.5C. During the charging phase, a constant current-constant voltage (CC-CV) mode is used, charging at a constant current of 0.5C to 4.3V and then maintaining a constant voltage of 4.3V until the current decays to 0.05C and charging stops. During the discharging phase, a constant current (CC) mode is used, discharging at a current of 0.5C to 2.8V.

[0138] Repeat the above charge and discharge cycle 500 times, and record the battery's discharge specific capacity on the first cycle and the discharge specific capacity on the 500th cycle.

[0139] Calculate the ratio of the discharge specific capacity of the 500th cycle to the discharge specific capacity of the first cycle to obtain the capacity retention rate of each test sample.

[0140] Table 3. Performance test data of all-solid-state batteries in Examples 1-3 and Comparative Examples 1-4 after 500 cycles at 4.3V high voltage.

[0141]

[0142] in conclusion:

[0143] Combining the data in Table 3 and Figure 5 500-cycle life curve at a high cutoff voltage of 4.3V. Figure 6 The capacity retention rate was analyzed using a bar chart after 500 cycles.

[0144] Figure 5 This diagram illustrates the discharge capacity decay process of an all-solid-state battery during long-cycle testing at 0.5C rate and a voltage range of 2.8V to 4.3V. The horizontal axis represents the number of charge-discharge cycles, and the vertical axis represents the discharge capacity. Curves with different gray levels and line shapes represent different test samples, and the corresponding examples or comparative examples are directly labeled in the figure. Figure 6 Extracted Figure 5 The ratio of the discharge specific capacity of the 500th cycle to that of the first cycle was quantitatively compared. In the figure, the first three dark gray bars represent the example, and the last four light gray bars represent the comparative examples. The percentage of capacity retention is precisely marked above the bars.

[0145] According to Table 3 and Figure 5 , Figure 6The data in the figure shows that the capacity decay of Examples 1-3 is extremely gradual, and the capacity retention rate is greater than 90% after 500 charge-discharge cycles at a high cutoff voltage of 4.3V. The test results of the examples confirm that a chemically stable LixPOySz composite layer was constructed in situ under thermodynamic conditions without damaging the positive electrode crystal structure and the solid electrolyte bulk phase structure. This interface layer physically blocks the direct contact between the deep unreacted sulfide electrolyte and the high-potential positive electrode, withstands high-potential oxidation at 4.3V, and avoids continuous decomposition during cycling.

[0146] In comparison, Figure 5 The comparison examples 1-3 exhibited varying degrees of rapid capacity drop or initial failure. Comparative example 1, using a conventional room-temperature cold-pressing process, showed a capacity retention rate dropping to 33.99% after 500 cycles. Relying solely on mechanical pressure to resolve the solid-solid interface physical contact resulted in contact failure and pore regeneration due to lattice expansion and contraction of the cathode material during long-term cycling. Furthermore, the lack of a chemical passivation barrier at the interface led to sulfur dioxide (S) degradation in the directly contacting sulfide solid electrolyte during 4.3V high-voltage charging. 2- The irreversible oxidation transformation of elemental sulfur and polysulfides leads to an increase in internal resistance and a rapid decay of capacity due to the accumulation of interfacial insulating products.

[0147] Comparative Example 2, with a heat treatment temperature set at 300℃, showed an initial discharge specific capacity of only 74.2 mAh / g, and a final capacity retention of 15.76%. Excessive heat caused severe thermal weight loss and structural collapse in the sulfide electrolyte phase, leading to volatilization. The gas inside the battery causes the bulk ion conduction network to break down, increasing internal resistance.

[0148] Comparative Example 3, subjected to a molding pressure of 300 MPa, exhibited a capacity retention of 57.11% after 500 cycles. The ultra-high mechanical pressure induced microcracks within the layered oxide cathode particles. During cycling, the electrolyte penetrated into the particles along these microcracks, causing side reactions. The newly exposed active material lacked protection, leading to continuous deactivation and severe capacity decay.

[0149] Comparative Example 4 used pre-artificial wrapping The coated cathode material, replacing the untreated raw powder, achieved a capacity retention of 82.56%, lower than the previous example. Insufficient physical bonding between the artificial surface coating and the active material resulted in localized micro-delamination of the coating under long-cycle volumetric strain. The in-situ generated LixPOySz composite layer involves interdiffusion and chemical reactions between lattice oxygen and phosphorus / sulfur atoms at the interface. The interfacial bonding is at the chemical bonding level, and the grain boundary defects provided by the amorphous or nanocrystalline structure ensure the continuity of lithium-ion transport. Its long-cycle mechanical durability is superior to traditional artificial coating technologies.

[0150] Figure 6The results clearly show that the capacity retention rates of Examples 1-3 are all greater than 90%, which is significantly better than the test results of room temperature cold pressing (Comparative Example 1), high temperature or high pressure molding (Comparative Examples 2 and 3), and traditional artificial coating (Comparative Example 4). This confirms that the interface stabilizing layer generated under the specific parameters of the present invention has excellent long-term high pressure physical and chemical barrier function.

[0151] Test Example 4: Multi-gradient rate discharge capability test

[0152] The all-solid-state coin cells assembled in Example 2, Comparative Example 1, and Comparative Example 4 were placed in a high and low temperature alternating test chamber. The test environment temperature was set to 25°C, and the cells were left to stand for 4 hours to allow the internal temperature of the cells to become uniform.

[0153] Connect the battery to a multi-channel battery testing system and set the charge / discharge voltage range to 2.8V to 4.3V. ).

[0154] To eliminate the interference of charging kinetics on the discharge test, a constant current-constant voltage (CC-CV) mode was uniformly adopted for all charging phases. The system was charged at a constant current of 0.2C to 4.3V, followed by constant voltage charging until the current dropped to 0.05C.

[0155] The discharge phase uses constant current (CC) mode. The discharge rate is set sequentially to 0.1C, 0.5C, 1.0C, 2.0C and 3.0C, and 5 charge-discharge cycles are performed continuously at each discharge rate gradient.

[0156] After the 3.0C rate test is completed, the discharge rate is restored to 0.1C, and 5 more charge-discharge cycles are performed to test the capacity recovery capability.

[0157] Record the discharge specific capacity of each cycle output by the test system, and extract the discharge specific capacity data of the last cycle (i.e., the 5th, 10th, 15th, 20th, 25th and 30th cycles) under each rate gradient for evaluation.

[0158] Table 4. Specific capacity test data of all-solid-state batteries in Example 2 and Comparative Examples 1 and 4 at multiple rate discharge levels.

[0159]

[0160] in conclusion:

[0161] Combining the data in Table 4 and Figure 7 Multi-gradient rate discharge cycle curves Figure 8 We analyzed the specific capacity comparison bar charts at various discharge rates.

[0162] Figure 7The multi-gradient rate discharge cycle curves are shown. The horizontal axis represents the number of cycles, and the vertical axis represents the discharge specific capacity. The test process covers five incremental discharge rate stages: 0.1C, 0.5C, 1.0C, 2.0C, and 3.0C, as well as a 0.1C capacity backtesting stage. Each rate stage is performed for 5 charge-discharge cycles, and the figure uses vertical dashed lines to divide each rate range. In the figure, solid lines and solid squares represent Example 2, dashed lines and triangles represent Comparative Example 4, and dotted lines and circles represent Comparative Example 1.

[0163] Figure 8 A bar chart comparing specific capacity at various discharge rates is presented. The horizontal axis represents the discharge rate gradient, and the vertical axis represents the discharge specific capacity. This chart extracts the discharge specific capacity data from the last cycle of each stage in the rate ladder test for quantitative comparison. Dark gray bars represent Example 2, light gray bars represent Comparative Example 1, and medium gray bars represent Comparative Example 4. The specific capacity value is labeled above each bar.

[0164] according to Figure 8 According to the data in Table 4, the discharge specific capacity of the three test samples showed little difference at a low rate of 0.1C. Example 2 exhibited good kinetic characteristics in the discharge rate test from 0.1C to 3.0C, with an actual discharge specific capacity of 192.43 mAh / g. Figure 7 The results show that the discharge specific capacity of Example 2 transitions smoothly across different rate stages. When the discharge rate increases progressively to 1.0C and 2.0C, the capacity remains at 164.81 mAh / g and 145.24 mAh / g, respectively. Under a high-current discharge condition of 3.0C, Example 2 still exhibits a stable capacity output platform, with its actual discharge specific capacity remaining at 121.8 mAh / g (121.75 mAh / g). Upon recovery to 0.1C, the capacity of Example 2 recovers to 189.6 mAh / g (189.62 mAh / g). The test data confirms that the LixPOySz composite layer (stabilizing layer) generated in situ under 50 MPa and 150℃ conditions is extremely thin, at the nanometer level. The amorphous or nanocrystalline structure contains numerous grain boundary defects and free volumes, constructing low-barrier lithium-ion transport channels. The extremely thin physical thickness and extremely short diffusion path allow ions to avoid severe concentration polarization and ohmic voltage drop under high-rate discharge conditions when crossing the solid-solid interface.

[0165] In comparison, Figure 7 The results show that the discharge specific capacity of Comparative Example 4 and Comparative Example 1 decreases significantly in a stepwise manner with increasing discharge rate, and essentially loses its discharge capacity at 3.0C. Comparative Example 4 uses traditional artificial coating. The coated cathode material exhibits a capacity of 180.52 mAh / g at 0.1C. However, with increasing discharge rate, its polarization increases rapidly, leading to a precipitous drop in capacity. At 2.0C and 3.0C, the discharge specific capacity plummets to 62.47 mAh / g and 18.9 mAh / g (18.93 mAh / g), respectively. Conventional wet or dry artificial coating techniques are limited by process precision, resulting in coating thicknesses typically in the hundreds of nanometers range with poor uniformity. While thicker physical coatings can provide some chemical passivation, they significantly lengthen the bulk diffusion distance of lithium ions, increasing kinetic transport impedance. At high current densities, the slow ion migration rate cannot match the external electron transport requirements, causing the battery's internal potential to rapidly reach the discharge cutoff voltage.

[0166] Comparative Example 1, using untreated cathode powder in direct contact with the solid electrolyte, exhibited the worst discharge rate performance. At 0.5C, the capacity had already decayed to 88.54 mAh / g, and at a high rate of 3.0C, the capacity dropped to 1.2 mAh / g (1.25 mAh / g), showing almost no capacity output. When the rate was restored to 0.1C, the capacity only recovered to 118.41 mAh / g, indicating irreversible capacity loss. The unmodified sulfide all-solid-state battery experienced interfacial side reactions early in the testing process, with the continuous accumulation of insulating byproducts at the interface disrupting the ion transport network. The deterioration of the interfacial contact and the formation of reaction dead zones led to a sharp increase in internal resistance, resulting in rapid degradation of kinetic performance during rate testing.

[0167] The data results of Example 2 confirm from the perspective of electrochemical kinetics that the ultrathin stable layer generated by the in-situ thermomechanical process solves the physical drawback of traditional thick coatings that hinder solid-state ion transport. Its interfacial kinetic transport performance is significantly better than that of traditional artificial coating technology with large physical thickness and untreated solid-solid contact interface, meeting the performance requirements of high power output of all-solid-state batteries.

Claims

1. A high-voltage cathode material having an in-situ formed stabilization interface layer, characterized in that, By weight percentage, it includes the following raw materials: 70% to 85% of nickel-rich layered oxide positive electrode active material particles with a median particle size of 3 μm to 8 μm, 10% to 25% of Argyrodite-type sulfide solid electrolyte powder with a median particle size of 1 μm to 3 μm, 1% to 5% of carbon black and 1% to 5% of styrene-butadiene rubber. The interface between the nickel-rich layered oxide positive electrode active material particles and the Argyrodite-type sulfide solid electrolyte powder has an interface stabilizing layer composed of lithium, phosphorus, oxygen and sulfur.

2. The high-voltage cathode material composition with an in-situ formed stabilization interface layer according to claim 1, characterized in that, The high-voltage cathode material with an in-situ formed stable interface layer is obtained by the following preparation method: In an argon atmosphere glove box, the nickel-rich layered oxide positive electrode active material particles, the Argyrodite type sulfide solid electrolyte powder, and the carbon black were weighed and placed in a mixing tank for mechanical stirring and dry mixing to obtain a dry-mixed powder. The styrene-butadiene rubber was dissolved in anhydrous toluene solvent to prepare a slurry. The slurry was then added to the dry-mixed powder in batches for dispersion treatment to obtain a solid-state battery cathode composite slurry. The all-solid-state battery positive electrode composite slurry is coated onto an aluminum foil current collector that has undergone surface carbon coating treatment, and then vacuum dried to remove the anhydrous toluene solvent, resulting in a dry positive electrode sheet. The positive electrode drying sheet is placed in a flat plate hot press, and static mechanical pressure is applied to the vertical surface of the positive electrode drying sheet. While maintaining the static mechanical pressure, a heating program is started to raise the temperature. The sheet is then subjected to constant temperature and pressure treatment under thermo-pressurization coupling. The heating program is then turned off, and the sheet is allowed to cool down naturally while maintaining the static mechanical pressure. The static mechanical pressure is then unloaded, and an interface stabilizing layer composed of lithium, phosphorus, oxygen, and sulfur is generated in situ at the interface between the nickel-rich layered oxide positive electrode active material particles and the Argyrodite-type sulfide solid electrolyte powder.

3. The high-voltage cathode material composition with an in-situ formed stabilization interface layer according to claim 2, characterized in that, The mechanical stirring and dry mixing is carried out in an argon atmosphere glove box with a dew point below -40°C and a water and oxygen content of less than 0.1 ppm for 1 hour.

4. The high-voltage cathode material composition with an in-situ formed stabilization interface layer according to claim 2, characterized in that, When the adhesive is added to the dry-mixed powder in batches for dispersion treatment, the final solid content of the all-solid-state battery cathode composite slurry is controlled to be 65%. The slurry is dispersed for 2 hours at 2000 rpm using a high-shear homogenizer to obtain the all-solid-state battery cathode composite slurry.

5. The high-voltage cathode material composition with an in-situ formed stabilization interface layer according to claim 2, characterized in that, The all-solid-state battery positive electrode composite slurry is coated onto the aluminum foil current collector that has undergone surface carbon coating treatment using a doctor blade coating machine to form a wet film coating. The thickness of the wet film coating is controlled to be 100 μm. The vacuum drying treatment is carried out at 100°C for 12 hours to remove the anhydrous toluene solvent.

6. The high-voltage cathode material composition with an in-situ formed stabilization interface layer according to claim 2, characterized in that, A static mechanical pressure of 10 MPa to 100 MPa is applied to the vertical surface of the positive electrode drying sheet. While maintaining the static mechanical pressure, the temperature of the template of the flatbed hot press is raised to 100°C to 250°C. The isothermal pressure treatment is carried out for 0.5 hours to 5 hours under the hot-press coupling state. The temperature is then naturally cooled to 25°C while maintaining the static mechanical pressure.

7. The high-voltage cathode material composition with an in-situ formed stabilization interface layer according to claim 6, characterized in that, The static mechanical pressure is 10MPa to 50MPa, the temperature of the template of the flatbed hot press is raised to 100℃ to 150℃, and the constant temperature and pressure holding time is 0.5 hours to 2.5 hours.

8. The high-voltage cathode material composition with an in-situ formed stabilization interface layer according to claim 6, characterized in that, The static mechanical pressure is 50MPa to 100MPa, the temperature of the template of the flat plate hot press is raised to 150°C to 250°C, and the constant temperature and pressure holding time is 2.5 hours to 5 hours.

9. The high-voltage cathode material composition with an in-situ formed stabilization interface layer according to claim 1, characterized in that, The thickness of the interface stabilizing layer, composed of lithium, phosphorus, oxygen and sulfur, does not exceed 100 nm.

10. The application of a high-voltage cathode component having an in-situ formed stabilization interface layer as described in any one of claims 1-9 in the preparation of an all-solid-state battery.

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