Solid‑state battery cell, battery device, electric device, and method for preparing porous carbon

Abstract

The present application provides a solid‑state battery cell, a battery device, an electric device, and a method for preparing porous carbon. In a first aspect, the present application provides a solid-state battery cell, comprising a negative electrode layer, a positive electrode layer, and an electrolyte layer; the electrolyte layer is located between the negative electrode layer and the positive electrode layer; the negative electrode layer comprises a negative electrode current collector and an interfacial layer located on at least one side of the negative electrode current collector; the interfacial layer comprises porous carbon; the specific surface area of the porous carbon is 50 m2 / g to 500 m2 / g; the ID / IG of the porous carbon is 1.68-1.80, wherein ID represents the intensity of the D peak of the Raman spectrum of the porous carbon at 1350±50 cm-1, and IG represents the intensity of the G peak of the Raman spectrum of the porous carbon at 1580±50 cm-1. The solid-state battery cell can have high initial coulombic efficiency, good rate performance, and good cycle performance.

Description

Solid-state battery cells, battery devices, electrical devices, and methods for preparing porous carbon.

[0001] Cross-reference of related applications

[0002] This application claims priority to Chinese Patent Application No. 202411939458.3, filed on December 26, 2024, entitled "Solid-state battery cell, battery device, power-consuming device, and method for preparing porous carbon", and Chinese Patent Application No. 202511950295.3, filed on December 23, 2025, entitled "Solid-state battery cell, battery device, power-consuming device, and method for preparing porous carbon", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a solid-state battery cell, a battery device, an electrical device, and a method for preparing porous carbon. Background Technology

[0004] Compared to battery cells using liquid electrolytes, solid-state battery cells use solid electrolyte materials, making them less prone to combustion and explosion, and thus offering high reliability and high energy density. Solid-state battery cells using lithium metal as the negative electrode typically have even higher energy density; however, these cells suffer from dendrite growth and significant volume expansion, which limits their practical applications. Summary of the Invention

[0005] This disclosure provides a solid-state battery cell, a battery device, an electrical device, and a method for preparing porous carbon. The solid-state battery cell can have high initial coulombic efficiency, good rate performance, and good cycle performance.

[0006] In a first aspect, this disclosure provides a solid-state battery cell, comprising a negative electrode layer, a positive electrode layer, and an electrolyte layer, wherein the electrolyte layer is located between the negative electrode layer and the positive electrode layer, the negative electrode layer comprising a negative electrode current collector and an interface layer located on at least one side of the negative electrode current collector, the interface layer comprising porous carbon, the porous carbon having a specific surface area of ​​50 m² / g. 2 / g-500m 2 / g, the porous carbon of I D / I G It is 1.68-1.80, I D The Raman spectrum of the porous carbon is at 1350±50 cm⁻¹. -1 The intensity of peak D at I G The Raman spectrum of the porous carbon is at 1580±50 cm⁻¹. -1 The intensity of the G peak at that location.

[0007] The interface layer of the negative electrode layer disclosed herein uses porous carbon with a specific surface area of ​​50 m². 2 / g-500m 2 Within this range (g), the large specific surface area of ​​porous carbon facilitates rapid lithium-ion transport to the negative electrode current collector surface, improving ion transport kinetics and reducing lithium-ion adsorption within the porous carbon. Good negative electrode ion transport kinetics allow the solid-state battery cell to maintain high discharge capacity even at high current densities, resulting in excellent rate performance. Furthermore, good negative electrode ion transport kinetics facilitate easier deposition and stripping of lithium ions at the negative electrode, reducing capacity decay during cycling and improving cycle stability. Fewer lithium ions adsorbed in the porous carbon allow for greater lithium-ion deposition on the negative electrode current collector surface, enhancing the initial coulombic efficiency of the solid-state battery cell.

[0008] The porous carbon I of the interface layer disclosed herein D / I G The concentration is controlled within the range of 1.68-1.80. Within this range, porous carbon has a certain graphitization structure and good electronic conductivity, which can uniformly distribute the electrons in the interface layer and regulate the uniform deposition of lithium. This can reduce dendrite growth problems and internal short circuit problems caused by dendrite growth, while keeping the irreversible loss of active lithium at a low level.

[0009] Therefore, the solid-state battery cell disclosed herein can have high initial coulombic efficiency, good rate performance and good cycle performance.

[0010] In some embodiments, the porous carbon I D / I G It is 1.71-1.75.

[0011] In some embodiments, the specific surface area of ​​the porous carbon is 100 m². 2 / g-450m 2 / g. Porous carbon that meets this specific surface area range can better improve the ion transport kinetics of the negative electrode, better uniform lithium ion deposition, and further reduce lithium ion adsorption in porous carbon, thereby further improving the first coulombic efficiency, rate performance, and cycle performance of solid-state battery cells.

[0012] In some embodiments, the porosity of the porous carbon is 50%-65%. Within this range, the porous carbon can have high structural strength, thereby better reducing the volume expansion of the negative electrode, improving the processing performance of solid-state battery cells, and also promoting the rapid transport of lithium ions to the surface of the negative electrode current collector, thus improving the ion transport kinetics of the negative electrode.

[0013] In some embodiments, the porous carbon has a mesoporous structure, the total volume of which is 5%-50% of the total pore volume of the porous carbon, optionally 10%-30%. Within this range, it facilitates the rapid deposition of lithium ions across the interface layer onto the surface of the negative electrode current collector, improving the negative electrode ion transport kinetics, and promoting uniform lithium ion deposition and reducing lithium ion deposition within the pores of the porous carbon. This enables solid-state battery cells to exhibit high initial coulombic efficiency, good cycle performance, and good rate performance.

[0014] In some embodiments, the pore structure of the porous carbon further includes at least one of a microporous structure or a macroporous structure.

[0015] In some embodiments, the porous carbon has a pore structure comprising a microporous structure, wherein the total volume of the microporous structure is less than 65% of the total pore volume of the porous carbon.

[0016] In some embodiments, the porous carbon has a pore structure including a macropore structure, wherein the total volume of the macropore structure is less than 70% of the total pore volume of the porous carbon.

[0017] In some embodiments, the pore size of the porous carbon ranges from 1.5 nm to 100 nm, and can be selected as 5 nm to 75 nm.

[0018] In some embodiments, the average pore size of the porous carbon is 5 nm-15 nm, optionally 6.5 nm-12 nm. When the average pore size of the porous carbon is within this range, it can have a suitable pore size distribution, which facilitates the rapid deposition of lithium ions through the interface layer onto the surface of the negative electrode current collector, improving the ion transport kinetics of the negative electrode; it also enhances the uniform deposition effect of the interface layer on lithium ions, facilitates the formation of a more uniform lithium metal layer on the surface of the negative electrode current collector, helps reduce dendrite growth problems and internal short circuit problems caused by dendrite growth; and it further reduces lithium ion deposition in the pores of the porous carbon, thereby further improving the initial coulombic efficiency, rate performance, and cycle performance of the solid-state battery cell.

[0019] In some embodiments, the total pore volume of the porous carbon is 0.1 cm³. 3 / g-0.5cm 3 / g, can be selected as 0.15cm 3 / g-0.35cm 3 / g. The total pore volume of porous carbon is within the above range. Porous carbon can have a suitable pore size distribution, which is beneficial for lithium ions to quickly pass through the interface layer and deposit on the surface of the negative electrode current collector, thereby improving the ion transport kinetics of the negative electrode; it is beneficial for improving the uniform deposition effect of the interface layer on lithium ions, which is beneficial for forming a more uniform lithium metal layer on the surface of the negative electrode current collector, which is beneficial for reducing dendrite growth problems and internal short circuit problems caused by dendrite growth; it is beneficial for porous carbon to have high structural strength, which is beneficial for reducing the volume expansion of the negative electrode; it is also beneficial for reducing the deposition of lithium ions in the pores of porous carbon, thereby further improving the initial coulombic efficiency, rate performance and cycle performance of solid-state battery cells.

[0020] In some embodiments, the volumetric particle size distribution (Dv50) of the porous carbon is 50 nm to 2 μm. A Dv50 of 50 nm to 2 μm is beneficial for the interface layer to have a suitable packing density, thereby enabling the negative electrode to have good ion transport kinetics, reducing negative electrode volume expansion, and minimizing internal short-circuit problems caused by dendrite growth. This further improves the rate performance and cycle performance of the solid-state battery cell.

[0021] In some embodiments, the particle size distribution (Dv90-Dv10) / Dv50 of the porous carbon is 1.5-4. A particle size distribution (Dv90-Dv10) / Dv50 of 1.5-4 is beneficial for the interface layer to have a suitable packing density. This allows the negative electrode to have good ion transport kinetics, reduces negative electrode volume expansion, and minimizes internal short circuit problems caused by dendrite growth, thereby further improving the rate performance and cycle performance of the solid-state battery cell.

[0022] In some embodiments, the compaction density of the porous carbon is 0.75 g / cm³. 3 -0.90g / cm 3 .

[0023] In some embodiments, the thickness of the interface layer is 1 μm-20 μm. Within this range, the interface layer exhibits good thickness uniformity and consistency, and lithium ions can easily penetrate the interface layer and deposit on the surface of the negative electrode current collector, thereby enabling the solid-state battery cell to possess high initial coulombic efficiency, good cycle performance, and good rate performance.

[0024] In some embodiments, the positive electrode layer includes a positive electrode current collector and a positive electrode active material layer located on at least one side of the positive electrode current collector. The positive electrode active material layer includes a solid electrolyte material and a positive electrode active material. The positive electrode active material includes one or more of lithium transition metal oxides and their modified materials, lithium phosphates and their modified materials, lithium titanate, lithium niobate, sulfur, selenium, and tellurium. The solid electrolyte material includes one or more of sulfide solid electrolyte materials, halide solid electrolyte materials, oxide solid electrolyte materials, and polymer solid electrolyte materials.

[0025] In some embodiments, the electrolyte layer comprises one or more of sulfide solid electrolyte materials, halide solid electrolyte materials, oxide solid electrolyte materials, and polymer solid electrolyte materials.

[0026] In some embodiments, the solid-state battery cell is a metal-free solid-state battery cell.

[0027] In some embodiments, when the solid-state battery cell is at 100% SOC, a metal layer is present between the negative electrode current collector and the interface layer.

[0028] In some embodiments, the NP ratio of the solid-state battery cell is 0.01-0.5, where the NP ratio is the ratio of the negative electrode capacity per unit area to the positive electrode capacity per unit area.

[0029] In a second aspect, this disclosure provides a battery device comprising a plurality of solid-state battery cells as described in the first aspect.

[0030] Thirdly, this disclosure provides an electrical device that includes a solid-state battery cell (as described in the first aspect) or a battery device (as described in the second aspect).

[0031] Fourthly, this disclosure provides a method for preparing porous carbon, comprising the following steps: mixing a carbon source and a pore-forming agent under a protective gas atmosphere for pre-carbonization treatment to obtain a porous carbon precursor material; then crushing the obtained porous carbon precursor material and further carbonizing it under a protective gas atmosphere at 1000℃-1600℃ to obtain porous carbon, wherein the specific surface area of ​​the porous carbon is 50 m². 2 / g-500m 2 / g, the porous carbon of I D / I G It is 1.68-1.80, I D The Raman spectrum of the porous carbon is at 1350±50 cm⁻¹. -1 The intensity of peak D at I G The Raman spectrum of the porous carbon is at 1580±50 cm⁻¹. -1 The intensity of the G peak at that location.

[0032] In some embodiments, the carbonization process takes 2-6 hours.

[0033] In some embodiments, the temperature of the pre-carbonization treatment is 300°C-600°C.

[0034] In some embodiments, the pre-carbonization treatment time is 20 min to 60 min.

[0035] In some embodiments, the carbon source includes one or more of the following: coal tar, coal pitch, petroleum residue, petroleum pitch, synthetic pitch, anthracite, aliphatic organic compounds, organic compounds containing carbonyl groups, organic compounds containing benzene rings, synthetic resins, epoxy resins, phenolic resins, sucrose, cellulose, lignin, glucose, starch, and gelatin.

[0036] In some embodiments, the pore-forming agent includes one or more of water vapor, potassium hydroxide, sodium hydroxide, calcium hydroxide, calcium oxide, magnesium oxide, magnesium hydroxide, melamine, aluminum oxide, and polymers.

[0037] In some embodiments, the mass ratio of the carbon source to the pore-forming agent is 1:1 to 1:3.5. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are merely some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the drawings without any creative effort.

[0039] Figure 1 shows a schematic diagram of a solid-state battery cell provided in some embodiments of this disclosure.

[0040] Figure 2 shows a schematic diagram of an electrical device provided in some embodiments of this disclosure.

[0041] The accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0042] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the solid-state battery cell, battery device, power-consuming device, and method for preparing porous carbon according to the present disclosure. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure and are not intended to limit the subject matter of the claims.

[0043] The "range" disclosed in this disclosure is defined by a lower limit and an upper limit, whereby a given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this disclosure, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0044] Unless otherwise specified, all embodiments and optional embodiments of this disclosure may be combined with each other to form new technical solutions, and such technical solutions should be considered as included in the disclosure of this disclosure.

[0045] Unless otherwise specified, all technical features and optional technical features of this disclosure can be combined to form new technical solutions, and such technical solutions should be considered as included in the disclosure of this disclosure.

[0046] Unless otherwise specified, all steps in this disclosure may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0047] Unless otherwise specified, in this disclosure, the terms "first," "second," etc., are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0048] In this disclosure, the terms "multiple" or "a variety" refer to two or more kinds.

[0049] In the description of the embodiments of this disclosure, unless otherwise specified, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0050] Unless otherwise stated, the test temperature for all parameters mentioned in this disclosure is 25°C.

[0051] The solid-state battery cells mentioned in the embodiments of this disclosure can independently perform charging and discharging functions. Solid-state battery cells can be cylindrical, cuboid, or other shapes, and the embodiments of this disclosure are not limited in this respect. Figure 1 shows a cuboid solid-state battery cell 5 as an example.

[0052] The battery apparatus mentioned in the embodiments of this disclosure may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple solid-state battery cells, which are connected in series, parallel, or mixed connections via busbars.

[0053] In some embodiments, a battery cell assembly is typically formed by arranging multiple solid-state battery cells.

[0054] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple solid-state battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple solid-state battery cells together with cable ties.

[0055] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0056] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0057] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple solid-state battery cells to the housing.

[0058] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0059] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0060] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0061] The technical solutions described in this disclosure are applicable to various electrical devices that use solid-state battery cells or battery devices, such as, but not limited to, mobile devices (e.g., mobile phones, tablets, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc. Solid-state battery cells and battery devices are used to store or provide electrical energy.

[0062] Figure 2 is a schematic diagram of an example electrical device. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0063] The solid-state battery cells disclosed herein may include coin cells, molded cells, hard-case cells, pouch cells, etc.

[0064] The battery cells provided in the embodiments of this disclosure can be negative electrode-free metal solid-state battery cells, such as negative electrode-free lithium metal solid-state battery cells.

[0065] A cathodeless lithium metal solid-state battery cell typically refers to a battery cell in which no negative electrode active material layer is actively placed on the negative electrode side during the manufacturing process. For example, during the manufacturing process, a negative electrode active material layer formed of carbon-based active materials such as graphite is not applied or deposited at the negative electrode, and a lithium-based metal layer is not actively placed on the negative electrode side. During the first charge, lithium ions gain electrons on the negative electrode side and deposit on the surface of the negative electrode current collector to form lithium metal. During discharge, the lithium metal can be converted back into lithium ions and return to the positive electrode, achieving cyclic charging and discharging.

[0066] Lithium metal possesses a high theoretical specific capacity (3860 mAh / g) and a low reduction potential (-3.04 V vs. SHE), making it a highly promising anode material. Compared to other solid-state battery cells, anode-free lithium metal solid-state battery cells exhibit higher volumetric and gravimetric energy densities, better reliability, and require no free lithium metal during assembly, thus simplifying the manufacturing process.

[0067] Currently, the main challenges facing single-cell lithium metal solid-state batteries without anodes are: the high reducibility of lithium metal, the large volume expansion of the anode caused by lithium metal deposition during charging and discharging, the dendrite growth problem caused by uneven lithium metal deposition, and the internal short circuit problem caused by dendrite growth.

[0068] To address these issues, modifying the interface between the anode and electrolyte layers is an excellent strategy. However, existing interface modification techniques suffer from complex processes, high costs, and limited performance improvements.

[0069] Therefore, embodiments of this disclosure provide a solid-state battery cell with high initial coulombic efficiency, good rate performance, and good cycle performance.

[0070] The solid-state battery cell provided in this embodiment includes a negative electrode layer, a positive electrode layer, and an electrolyte layer, with the electrolyte layer located between the negative electrode layer and the positive electrode layer.

[0071] The negative electrode layer includes a negative electrode current collector and an interface layer located on at least one side of the negative electrode current collector. The interface layer includes porous carbon with a specific surface area of ​​50 m². 2 / g-500m 2 / g, I of porous carbon D / I G It is 1.68-1.80, I D The Raman spectrum of porous carbon is shown at 1350±50 cm⁻¹. -1 The intensity of peak D at I G The Raman spectrum of porous carbon is shown at 1580±50 cm⁻¹. -1 The intensity of the G peak at that location.

[0072] Specific surface area reflects the surface activity of porous carbon. A small specific surface area means fewer active sites or defects, hindering rapid lithium-ion conduction and transport to the negative electrode current collector surface. Conversely, an excessively large specific surface area results in excessive interfaces, leading to lithium-ion adsorption and reduced lithium metal deposition on the negative electrode current collector surface, thus lowering the initial coulombic efficiency of the solid-state battery cell. The interface layer of the negative electrode layer in this disclosure uses porous carbon with a specific surface area of ​​50 m². 2 / g-500m 2Within this range, the large specific surface area of ​​porous carbon can promote the rapid transport of lithium ions to the surface of the negative electrode current collector, improve the ion transport kinetics of the negative electrode, and reduce the adsorption of lithium ions in porous carbon.

[0073] The favorable ion transport kinetics at the negative electrode allow solid-state battery cells to maintain high discharge capacity even at high current densities, resulting in excellent rate performance. Good ion transport kinetics also facilitate lithium ion deposition and stripping at the negative electrode, reducing capacity decay during cycling and improving cycle stability. Furthermore, fewer lithium ions adsorbed in the porous carbon allow for greater lithium ion deposition onto the negative electrode current collector surface, enhancing the initial coulombic efficiency of the solid-state battery cell.

[0074] In Raman spectroscopy, I D / I G It reflects the degree of defects and disorder in porous carbon, and can also reflect the degree of graphitization of porous carbon. The D peak represents the degree of defects and disorder in porous carbon, I D The smaller the value, the more complete and ordered the porous carbon structure is. The G peak represents lattice vibrations and the degree of order, while the I peak represents... G A higher I value indicates a relatively compact and stable porous carbon structure. D / I G The smaller the graphitization level, the higher the degree of graphitization and the lower the degree of disorder in porous carbon. Understandably, when the graphitization level of porous carbon is too high, its own lithium intercalation capacity increases, making it difficult for some lithium ions to deposit on the surface of the negative electrode current collector. This leads to increased loss of active lithium and a decrease in the initial coulombic efficiency and capacity retention of the solid-state battery cell.

[0075] The porous carbon I of the interface layer disclosed herein D / I G The concentration is controlled within the range of 1.68-1.80. Within this range, porous carbon has a certain graphitization structure and good electronic conductivity, which can uniformly distribute the electrons in the interface layer and regulate the uniform deposition of lithium. This can reduce dendrite growth problems and internal short circuit problems caused by dendrite growth, while keeping the irreversible loss of active lithium at a low level.

[0076] Therefore, the solid-state battery cell disclosed herein can have high initial coulombic efficiency, good rate performance and good cycle performance.

[0077] The specific surface area of ​​porous carbon can be measured using the nitrogen adsorption specific surface area analysis method according to GB / T 19587-2017, and calculated using the BET (Brunauer Emmett Teller) method. The testing instrument can be the Tri-Star 3020 specific surface area and pore size analyzer from Micromeritics, USA.

[0078] I of porous carbon D / I G The test can be performed using a Raman spectrometer. D The Raman spectrum of porous carbon is shown at 1350±50 cm⁻¹. -1 The intensity of peak D at I G The Raman spectrum of porous carbon is shown at 1580±50 cm⁻¹. -1 The intensity of the G peak at the location was measured. The test conditions were: excitation wavelength 532 nm, grating 600 lines, objective lens 50x, integration time 10 s, cumulative scan 3 times, area scan, obtaining the D and G peak intensities at 100 points, and calculating the I at 100 points. D / I G Remove the largest and smallest 30 I's. D / I G The average value of the remaining 40 points is the I of porous carbon. D / I G The testing instrument can be a Horiba LabRAM HR800 Raman spectrometer.

[0079] In some embodiments, porous carbon can be amorphous carbon.

[0080] In some embodiments, the solid-state battery cell has a metal layer between the negative electrode current collector and the interface layer when it is at 100% SOC. The metal layer is formed by the deposition of ions (e.g., lithium ions) that migrate from the positive electrode layer during charging.

[0081] Optionally, when the solid-state battery cell is at 100% SOC, a lithium metal layer is present between the negative electrode current collector and the interface layer.

[0082] A solid-state battery cell at 100% SOC means that the solid-state battery cell is charged to its upper limit cutoff voltage at a current density of 0.33C. At this point, the solid-state battery cell is considered to be at 100% SOC.

[0083] The upper cutoff voltage is known in the art, and the voltage recommended in the product specification sheet can be used. For example, the positive electrode active material is a lithium transition metal oxide or its modified form, such as LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (abbreviated as NCM333), LiNi0.5 Co 0.2 Mn 0.3 O2 (abbreviated as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (abbreviated as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (abbreviated as NCM811), LiNi 0.96 Co 0.02 Mn 0.02 O2 (abbreviated as Ni96), LiNi 0.80 Co 0.15 Al 0.05 O2, the upper limit cutoff voltage can be 4.3V (vs. Li). + / Li).

[0084] In some embodiments, the NP ratio of a solid-state battery cell can be greater than 0 and less than or equal to 0.5.

[0085] Optionally, the NP ratio of a solid-state battery cell can be 0.01-0.5, for example, it can be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, or any of the above values. The NP ratio is the ratio of the unit area capacity of the negative electrode (i.e., the interface layer) to the unit area capacity of the positive electrode, that is, the unit area capacity of the negative electrode / the unit area capacity of the positive electrode.

[0086] Alternatively, the NP ratio of a solid-state battery cell can be 0.01-0.4, 0.01-0.3, 0.01-0.2, 0.01-0.1, 0.01-0.08, or 0.01-0.05.

[0087] The NP ratio can be tested using the following method.

[0088] The negative electrode layer was removed from a solid-state battery cell and placed in a solid-state battery mold for testing. The counter electrode was a lithium-indium alloy sheet separated by an electrolyte layer. The battery was discharged to 0.01V (vs. Li) at a current density of 0.1C. + / Li), and then charged to 2V at a current density of 0.1C (vs. Li). + The resulting charging capacity ( / Li) is the negative electrode capacity. Negative electrode capacity per unit area = negative electrode capacity / negative electrode layer area.

[0089] The positive electrode layer is removed from a solid-state battery cell and placed in a solid-state battery mold for testing. A lithium-indium alloy sheet is used as the counter electrode, separated by an electrolyte layer. The battery is charged at a current density of 0.1C to the upper cutoff voltage, and then discharged at a current density of 0.1C to the lower cutoff voltage. The resulting discharge capacity is the positive electrode capacity. Positive electrode capacity per unit area = Positive electrode capacity / Positive electrode layer area.

[0090] The NP ratio of a solid-state battery cell = negative electrode unit area capacity / positive electrode unit area capacity.

[0091] Both the upper and lower cutoff voltages are known in the art, and the voltages recommended in the product specifications can be used. For example, the positive electrode active material is a lithium transition metal oxide or its modified form, such as LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (abbreviated as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (abbreviated as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (abbreviated as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (abbreviated as NCM811), LiNi 0.96 Co 0.02 Mn 0.02 O2 (abbreviated as Ni96), LiNi 0.80 Co 0.15 Al 0.05 O2, the upper limit cutoff voltage can be 4.3V (vs. Li). + / Li), the lower cutoff voltage can be 2.5V (vs. Li). + / Li).

[0092] I of porous carbon D / I G It is 1.68-1.80, for example, it can be 1.68, 1.69, 1.70, 1.71, 1.72, 1.73, 1.74, 1.75, 1.76, 1.77, 1.78, 1.79, 1.80, or any range of the above values.

[0093] Alternatively, porous carbon I D / I G It is 1.71-1.75.

[0094] The specific surface area of ​​porous carbon is 50 m². 2 / g-500m 2 / g, for example, can be 50m 2 / g、60m 2 / g、70m 2 / g、80m 2 / g、90m 2 / g, 100m 2 / g、110m 2 / g、120m 2 / g、130m 2 / g, 140m 2 / g, 150m 2 / g、160m 2 / g、170m 2 / g、180m 2 / g、190m 2 / g、200m 2 / g、210m 2 / g、220m 2 / g、230m 2 / g、240m 2 / g、250m 2 / g、260m 2 / g、270m 2 / g、280m 2 / g、290m 2 / g、300m 2 / g、310m 2 / g、320m 2 / g、330m 2 / g、340m 2 / g, 350m 2 / g、360m 2 / g、370m 2 / g、380m 2 / g、390m 2 / g、400m 2 / g、410m 2 / g、420m 2 / g、430m 2 / g、440m 2 / g、450m 2 / g、460m 2 / g、470m 2 / g、480m 2 / g、490m 2 / g、500m 2 / g, or any range of the above values.

[0095] Optionally, the specific surface area of ​​porous carbon can be 80 m². 2 / g-500m 2 / g, 80m 2 / g-480m 2 / g, 80m 2 / g-450m 2 / g, 80m 2 / g-420m 2 / g, 80m 2 / g-400m 2 / g, 80m 2 / g-380m 2 / g, 100m 2 / g-500m 2 / g, 100m 2 / g-480m 2 / g, 100m 2 / g-450m 2 / g, 100m 2 / g-420m 2 / g, 100m 2 / g-400m 2 / g, 100m 2 / g-380m 2 / g, 130m 2 / g-500m 2 / g, 130m 2 / g-480m 2 / g, 130m 2 / g-450m 2 / g, 130m 2 / g-420m 2 / g, 130m 2 / g-400m 2 / g, 130m 2 / g-380m 2 / g, 150m 2 / g-500m 2 / g, 150m 2 / g-480m 2 / g, 150m 2 / g-450m 2 / g, 150m 2 / g-420m 2 / g, 150m 2 / g-400m 2 / g, 150m 2 / g-380m2 / g.

[0096] Porous carbon that meets this specific surface area range can better improve the ion transport kinetics of the negative electrode, better uniform lithium ion deposition, and further reduce lithium ion adsorption in porous carbon, thereby further improving the first coulombic efficiency, rate performance, and cycle performance of solid-state battery cells.

[0097] In some embodiments, the porosity of the porous carbon is 50%-65%, for example, it can be 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, or any range of the above values.

[0098] The porosity of porous carbon reflects the richness of its pore structure. Low porosity in porous carbon indicates a limited pore structure, typically with few internal pores or many large pores, which hinders the rapid transport of lithium ions to the negative electrode current collector surface. Conversely, excessively high porosity results in poor structural strength, making it unable to withstand the volume changes caused by lithium metal deposition and failing to reduce negative electrode volume expansion. Furthermore, porous carbon is prone to breakage during solid-state battery cell assembly, such as during pressing, which affects the processing performance of the solid-state battery cells. The porous carbon used in the interface layer of the negative electrode layer in this disclosure has a porosity of 50%-65%. Within this range, porous carbon can possess high structural strength, thereby better reducing negative electrode volume expansion, improving the processing performance of solid-state battery cells, and promoting rapid lithium ion transport to the negative electrode current collector surface, thus enhancing negative electrode ion transport kinetics.

[0099] Optionally, the porosity of the porous carbon can be 51%-65%, 52%-65%, 53%-65%, 54%-65%, 55%-65%, 51%-62%, 52%-62%, 53%-62%, 54%-62%, 55%-62%, 51%-60%, 52%-60%, 53%-60%, 54%-60%, or 55%-60%.

[0100] Porous carbon within this porosity range can better improve the ion transport kinetics of the negative electrode, better achieve uniform lithium-ion deposition, and better reduce the volume expansion of the negative electrode, thereby further improving the rate performance and cycle performance of solid-state battery cells.

[0101] The porosity of porous carbon can be tested using the gas displacement method, referring to GB / T 24586-2009. Porosity = (V1-V2) / V1×100%, where V1 is the apparent volume of the sample and V2 is the actual volume. Nitrogen gas is used for the test. A Micromeritics AccuPyc II 1340 true density meter can be used as the testing instrument.

[0102] In some embodiments, the pore structure of the porous carbon includes a mesoporous structure, and the total volume of the mesoporous structure can be 5%-50% of the total pore volume of the porous carbon, for example, it can be 5%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, or any range of the above values.

[0103] According to the International Union of Pure and Applied Chemistry (IUPAC), pores with a diameter <2 nm are defined as micropores, pores with a diameter between 2 nm and 50 nm are defined as mesopores, and pores with a diameter >50 nm are defined as macropores.

[0104] The small pore size of microporous structures hinders the rapid passage of lithium ions through the interface layer, thus hindering the interface layer from achieving uniform lithium ion deposition and reducing dendrite growth. Conversely, the large pore size of macroporous structures makes it easier for lithium ions to deposit within them, which also hinders the rapid passage of lithium ions through the interface layer and reduces the interface layer's ability to achieve uniform lithium ion deposition and reduce dendrite growth.

[0105] The total volume of the mesoporous structure in porous carbon is 5%-50% of the total pore volume of porous carbon. Within this range, it is beneficial for lithium ions to quickly pass through the interface layer and deposit on the surface of the negative electrode current collector, thereby improving the ion transport dynamics of the negative electrode. It is also beneficial for uniform lithium ion deposition and reducing lithium ion deposition in the pores of porous carbon. As a result, solid-state battery cells can have high initial coulombic efficiency, good cycle performance and good rate performance.

[0106] Optionally, the total volume of the mesoporous structure can be 5%-42%, 5%-38%, 5%-34%, 5%-30%, 5%-28%, 8%-42%, 8%-38%, 8%-34%, 8%-30%, 8%-28%, 10%-42%, 10%-38%, 10%-34%, 10%-30%, 10%-28%, 12%-42%, 12%-38%, 12%-34%, 12%-30%, 12%-28% of the total pore volume of the porous carbon.

[0107] Porous carbon within this range can better improve the ion transport kinetics of the negative electrode, further homogenize lithium-ion deposition and reduce lithium-ion adsorption in porous carbon, thereby further improving the first coulombic efficiency, rate performance and cycle performance of solid-state battery cells.

[0108] In some embodiments, the pore structure of porous carbon further includes at least one of microporous structure or macroporous structure.

[0109] Optionally, the pore structure of the porous carbon includes a microporous structure, and the total volume of the microporous structure can be less than 65% of the total pore volume of the porous carbon. More preferably, the total volume of the microporous structure can be less than 60%, less than 55%, less than 50%, less than 45%, or less than 40% of the total pore volume of the porous carbon.

[0110] Optionally, the pore structure of the porous carbon includes a macroporous structure, and the total volume of the macroporous structure can be less than 70% of the total pore volume of the porous carbon. More preferably, the total volume of the macroporous structure can be less than 65% and less than 60% of the total pore volume of the porous carbon.

[0111] In some embodiments, the pore size of the porous carbon can be in the range of 1.5 nm to 100 nm, and optionally 5 nm to 75 nm.

[0112] The pore size range of porous carbon refers to the range from the minimum pore size to the maximum pore size of porous carbon.

[0113] In some embodiments, the average pore size of the porous carbon can be 5nm-15nm, for example, it can be 5nm, 5.5nm, 6nm, 6.5nm, 7nm, 7.5nm, 8nm, 8.5nm, 9nm, 9.5nm, 10nm, 10.5nm, 11nm, 11.5nm, 12nm, 12.5nm, 13nm, 13.5nm, 14nm, 14.5nm, 15nm, or any range of the above values.

[0114] The average pore size of porous carbon is within the above-mentioned range. Porous carbon can have a suitable pore size distribution, which is conducive to the rapid passage of lithium ions through the interface layer and deposition on the surface of the negative electrode current collector, thereby improving the ion transport kinetics of the negative electrode. It is also conducive to improving the uniform deposition effect of the interface layer on lithium ions, forming a more uniform lithium metal layer on the surface of the negative electrode current collector, reducing dendrite growth problems and internal short circuit problems caused by dendrite growth, and reducing the deposition of lithium ions in the pores of porous carbon. This can further improve the initial coulombic efficiency, rate performance and cycle performance of solid-state battery cells.

[0115] Optionally, the average pore size of the porous carbon can be 5.5nm-14nm, 5.5nm-13nm, 5.5nm-12nm, 6nm-14nm, 6nm-13nm, 6nm-12nm, 6.5nm-14nm, 6.5nm-13nm, or 6.5nm-12nm.

[0116] In some embodiments, the total pore volume of the porous carbon can be 0.1 cm³. 3 / g-0.5cm 3 / g, for example, can be 0.1cm 3 / g, 0.12cm 3 / g, 0.15cm 3 / g, 0.18cm 3 / g, 0.2cm 3 / g, 0.22cm 3 / g, 0.25cm 3 / g, 0.28cm 3 / g, 0.3cm 3 / g, 0.32cm 3 / g, 0.35cm 3 / g, 0.38cm 3 / g, 0.4cm 3 / g, 0.42cm 3 / g, 0.45cm 3 / g, 0.48cm 3 / g, 0.5cm 3 / g, or any range of the above values.

[0117] When the total pore volume of porous carbon is within the aforementioned range, porous carbon can have a suitable pore size distribution, which is beneficial for lithium ions to quickly pass through the interface layer and deposit on the surface of the negative electrode current collector, thereby improving the ion transport kinetics of the negative electrode; it is beneficial for improving the uniform deposition effect of the interface layer on lithium ions, which is beneficial for forming a more uniform lithium metal layer on the surface of the negative electrode current collector, which is beneficial for reducing dendrite growth problems and internal short circuit problems caused by dendrite growth; it is beneficial for porous carbon to have high structural strength, which is beneficial for reducing the volume expansion of the negative electrode; it is also beneficial for reducing the deposition of lithium ions in the pores of porous carbon, thereby further improving the initial coulombic efficiency, rate performance and cycle performance of solid-state battery cells.

[0118] Optionally, the total pore volume of the porous carbon can be 0.12 cm³. 3 / g-0.45cm 3 / g, 0.12cm 3 / g-0.4cm 3 / g, 0.12cm 3 / g-0.35cm 3 / g, 0.15cm 3 / g-0.45cm 3 / g, 0.15cm 3 / g-0.4cm 3 / g, 0.15cm 3 / g-0.35cm 3 / g.

[0119] The maximum pore size, minimum pore size, average pore size, and total pore volume, total volume of mesoporous structure, total volume of microporous structure, and total volume of macroporous structure of porous carbon can be determined using a specific surface area analyzer, referring to GB / T21650.2-2008. The testing instrument can be a TristarII 3020 fully automatic specific surface area and porosity analyzer.

[0120] In some embodiments, the volumetric particle size Dv50 of the porous carbon can be 50 nm to 2 μm, for example, it can be 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2 μm, or any range of the above values.

[0121] The volumetric distribution of porous carbon with a particle size Dv50 of 50nm-2μm is beneficial for the interface layer to have a suitable packing density. This can not only enable the negative electrode to have good ion transport kinetics, but also reduce the volume expansion of the negative electrode and reduce the internal short circuit problem caused by dendrite growth, thereby further improving the rate performance and cycle performance of solid-state battery cells.

[0122] In some embodiments, the particle size distribution (Dv90-Dv10) / Dv50 of porous carbon can be 1.5-4, for example, it can be 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, or any range of the above values.

[0123] The particle size distribution (Dv90-Dv10) / Dv50 of porous carbon is 1.5-4, which is beneficial for the interface layer to have a suitable packing density. This can not only enable the negative electrode to have good ion transport kinetics, but also reduce the volume expansion of the negative electrode and reduce the internal short circuit problem caused by dendrite growth, thereby further improving the rate performance and cycle performance of solid-state battery cells.

[0124] Dv10, Dv50, and Dv90 represent the particle sizes corresponding to a cumulative volumetric distribution percentage of 10%, 50%, and 90%, respectively. These values ​​can be determined using a laser particle size analyzer, referring to GB / T 19077-2016. During testing, add 1g of the sample to a clean small beaker and 20ml of deionized water. Sonicate at 53kHz / 120W for 5 minutes to ensure complete dispersion. Turn on the laser particle size analyzer, clean the optical path system, and automatically test the background. Stir the sonicated solution to ensure uniform dispersion, place it in the sample cell as required, and begin measuring the particle size. A MasterSizer 3000 laser particle size analyzer can be used as the testing instrument.

[0125] In some embodiments, the compaction density of porous carbon can be 0.75 g / cm³. 3 -0.90g / cm 3 .

[0126] The compaction density of porous carbon can be tested according to GB / T 24533-2009. The specific test method is as follows: weigh a sample of 1.0000±0.0500g and place it in a test mold with a diameter of 13mm (e.g., CARVER#3619). Then place the sample in the testing equipment. The test conditions are: 5 tons pressure, pressure increase rate 10mm / min, pressure increase holding time 30s, pressure release rate 30mm / min, pressure release holding time 10s. The compaction density of the sample is measured upon pressure release. The compaction density of the sample = sample mass / (mold area * sample thickness). The testing equipment can be a UTM7305 compaction density tester.

[0127] In some embodiments, the mass percentage of porous carbon, based on the total mass of the interface layer being 100%, can be 65% or more, for example, 70% or more, 75% or more, 80% or more, 85% or more, or 90% or more.

[0128] In some embodiments, the interface layer may further include an adhesive.

[0129] Optionally, the adhesive may include, but is not limited to, one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), carboxymethyl chitosan (CMCS), methyl vinyl silicone rubber, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), thermoplastic styrene-butadiene rubber (SBS), isoprene rubber, butadiene rubber (BR), ethyl cellulose, fluororubber, and acrylate rubber.

[0130] The negative electrode current collector has two surfaces opposite each other in its thickness direction, and the interface layer is disposed on one or both of the two opposite surfaces of the negative electrode current collector.

[0131] In some embodiments, the thickness of the interface layer can be 1μm-20μm, for example, it can be 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, or any range of the above values.

[0132] Understandably, increasing the thickness of the interface layer increases its consistency and uniformity, reduces the proportion of uncoated areas and the difficulty of the process. However, when the interface layer is too thick, it becomes more difficult for lithium ions to pass through the interface layer, and some lithium may be deposited in the pores of porous carbon, resulting in increased loss of active lithium and reduced initial coulombic efficiency and capacity retention of solid-state battery cells.

[0133] The thickness of the interface layer disclosed herein is controlled within the range of 1μm-20μm. Within this range, the thickness of the interface layer has good consistency and uniformity, and lithium ions can easily pass through the interface layer and deposit on the surface of the negative electrode current collector. This enables the solid-state battery cell to have high initial coulombic efficiency, good cycle performance, and good rate performance.

[0134] Optionally, the thickness of the interface layer can be 2μm-18μm, 3μm-16μm, 4μm-14μm, 5μm-12μm, 6μm-12μm, 7μm-12μm, or 8μm-12μm.

[0135] The thickness of the interface layer mentioned above refers to the thickness of the interface layer on one of the surfaces of the negative electrode current collector.

[0136] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. The metal foil may be a pure metal, an alloy, or a surface-treated metal, such as, but not limited to, stainless steel foil, copper foil, nickel foil, and titanium foil. The composite current collector may include a polymer substrate and a metal material layer formed on at least one surface of the polymer substrate. As an example, the metal material may include, but is not limited to, one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymer substrate may include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0137] It should be noted that the above-mentioned tests on various parameters of porous carbon or interface layer can be performed by sampling from the prepared solid-state battery cell according to the following steps: Discharge the solid-state battery cell (for safety reasons, the solid-state battery cell is generally left in a fully discharged state); after disassembling the solid-state battery cell, remove the negative electrode layer, and then sample from the negative electrode layer to test the parameters related to the porous carbon or interface layer.

[0138] [Positive electrode layer]

[0139] The positive electrode layer can be prepared by either a dry process or a wet process.

[0140] In some embodiments, the positive electrode layer includes a positive electrode current collector and a positive electrode active material layer located on at least one side of the positive electrode current collector, wherein the positive electrode active material layer includes a solid electrolyte material and a positive electrode active material.

[0141] In some embodiments, the positive current collector may be a metal foil or a composite current collector. The metal foil may be a pure metal, an alloy, or a surface-treated metal, such as, but not limited to, stainless steel foil, carbon-coated aluminum foil, or aluminum foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. As an example, the metal material may include, but is not limited to, one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymer substrate may include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene.

[0142] In some embodiments, the positive electrode layer may not require an additional positive electrode current collector; for example, the stainless steel sheet of the mold battery can be directly used as the positive electrode current collector.

[0143] In some embodiments, the positive electrode active material may include one or more of lithium transition metal oxides and their modified forms, lithium phosphates and their modified forms, lithium titanate, lithium niobate, sulfur, selenium, and tellurium.

[0144] Optionally, examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and lithium-rich manganese-based materials.

[0145] Optionally, examples of lithium phosphates may include, but are not limited to, one or more of lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0146] In some embodiments, to further improve the energy density of a solid-state battery cell, the positive electrode active material may include materials of the general formula Li. a Ni b Co c M d O e A f One or more of lithium transition metal oxides and their modified materials. 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M may include one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, and B, and A may include one or more of N, F, S, and Cl. Optionally, 0.6≤b<1, 0.8≤b<1.

[0147] As an example, the positive electrode active material may include, but is not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (abbreviated as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (abbreviated as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (abbreviated as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (abbreviated as NCM811), LiNi 0.96 Co 0.02 Mn 0.02 O2 (abbreviated as Ni96), LiNi 0.80 Co 0.15 Al 0.05 One or more of O2, LiFePO4, LiMnPO4 and their respective modified materials.

[0148] The modified materials for the above-mentioned positive electrode active materials can be doped and / or surface coated.

[0149] During the charging and discharging process, solid-state battery cells undergo Li insertion / extraction and consumption, resulting in varying Li molar content at different discharge states. In this disclosure, the Li molar content listed for positive electrode active materials represents the initial state of the material, i.e., the state before material addition. As the positive electrode active material is applied to a solid-state battery cell, the Li molar content changes after charge-discharge cycles. Similarly, the O molar content listed for positive electrode active materials in this disclosure is only a theoretical value; lattice oxygen release causes changes in the O molar content, leading to fluctuations in the actual O molar content.

[0150] In some embodiments, the solid electrolyte material in the positive electrode layer may include one or more of the following: sulfide solid electrolyte material, halide solid electrolyte material, oxide solid electrolyte material, and polymer solid electrolyte material.

[0151] Optionally, the sulfide solid electrolyte material may include one or more of the following: silver-germanium sulfide type, LGPS type, Li2S-GeS2 type, Li2S-P2S5 type, Li2S-SiS2 type, and Li2S-MeS-P2S5 type sulfide solid electrolyte materials. Me may include one or more of Si, Ge, Sn, and Al.

[0152] Optionally, the sulfide solid electrolyte material of the silver-germanium sulfide type may include Li 6±s P 1-j A j S 5±s-t B t X 1±s The material has the following properties: 0≤j<1, 0≤t<1, 0≤s<1, A includes one or more elements from Ge, Si, Sn and Sb, B includes one or more elements from O, Se and Te, and X includes one or more elements from Cl, Br, I and F.

[0153] Optionally, LGPS-type sulfide solid electrolyte materials may include those with the chemical formula Li 10±δ5 Ge 1-g G g P 2-q Q q S 12- w W w The material has the following properties: 0≤δ5<1, 0≤g≤1, 0≤q≤2, 0≤w<1, G includes one or two elements from Si and Sn, Q includes Sb, and W includes one or more elements from O, Se, Te, Cl, Br, I, and F.

[0154] Optionally, as an example, sulfide solid electrolyte materials may include Li6PS5Cl, Li6PS5Br, Li 10 GeP2S12 Li3PS4, Li7P3S 11 One or more of them.

[0155] Optionally, the halide solid electrolyte material may be one or more of Li3YCl6, Li3YBr6, Li3ErCl6, Li3InCl6, and Li3InBr6, including but not limited to.

[0156] Optionally, the oxide solid electrolyte material may include one or more of the following: NASICON type solid electrolyte, LISICON type solid electrolyte, perovskite type solid electrolyte, and garnet type solid electrolyte.

[0157] As an example, oxide solid electrolyte materials may include, but are not limited to, Li5La3Ti2O 12 Li7La3Zr2O 12 Li4Ti5O 12 Li 14 Zn(GeO4)4, LiTi2(PO4)3, Li 1+x Al x Ti 2-x (PO4)3, Li 1+y Al y Ge 2-y One or more of (PO4)3, 0 < x < 2, 0 < y < 2.

[0158] Optionally, the polymer solid electrolyte material can be formed by complexing a polymer matrix material with a lithium salt. Optionally, the polymer matrix material can be one or more of, but not limited to, polyethylene oxide (PEO) and its derivatives, polypropylene oxide (PPO) and its derivatives, polycarbonate (PPC), polyacrylonitrile (PAN), polysiloxane (PDMS), polyvinylidene fluoride (PVDF), and polymethyl methacrylate (PMMA). Optionally, the lithium salt can be one or more of, but not limited to, LiClO4, LiAsF4, LiPF6, LiBF4, LiTFSI, and LiFSI.

[0159] Optionally, the polymer solid electrolyte material may also include an inert filler, which can reduce the crystallinity of the polymer and improve its mechanical properties. Optionally, the inert filler may include, but is not limited to, one or more of TiO2, Al2O3, ZrO2, and SiO2.

[0160] In some embodiments, the positive electrode active material layer may further include a positive electrode conductive agent.

[0161] Optionally, the positive electrode conductive agent may be one or more of the following, including but not limited to superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes (CNTs), graphene, carbon nanofibers, and vapor-grown carbon fibers (VGCF).

[0162] In some embodiments, the positive electrode active material layer may or may not include a positive electrode binder, and can be adjusted according to the positive electrode composition and the preparation process of the solid-state battery cell.

[0163] Optionally, the positive electrode binder may include, but is not limited to, one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, methyl vinyl silicone rubber, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), thermoplastic styrene-butadiene rubber (SBS), isoprene rubber, cis-butadiene rubber (BR), ethyl cellulose, fluororubber, and acrylate rubber.

[0164] [Electrolyte layer]

[0165] The electrolyte layer can be prepared by a dry process or a wet process.

[0166] In some embodiments, the electrolyte layer comprises a solid electrolyte material. Optionally, the solid electrolyte material may include one or more of sulfide solid electrolyte materials, halide solid electrolyte materials, oxide solid electrolyte materials, and polymer solid electrolyte materials.

[0167] Optionally, the sulfide solid electrolyte material may include one or more of the following: silver-germanium sulfide type, LGPS type, Li2S-GeS2 type, Li2S-P2S5 type, Li2S-SiS2 type, and Li2S-MeS-P2S5 type sulfide solid electrolyte materials. Me may include one or more of Si, Ge, Sn, and Al.

[0168] Optionally, the sulfide solid electrolyte material of the silver-germanium sulfide type may include Li 6±s P 1-j A j S 5±s-t B t X 1±s The material has the following properties: 0≤j<1, 0≤t<1, 0≤s<1, A includes one or more elements from Ge, Si, Sn and Sb, B includes one or more elements from O, Se and Te, and X includes one or more elements from Cl, Br, I and F.

[0169] Optionally, LGPS-type sulfide solid electrolyte materials may include those with the chemical formula Li 10±δ5 Ge 1-g G g P 2-q Q q S 12- w W w The material has the following properties: 0≤δ5<1, 0≤g≤1, 0≤q≤2, 0≤w<1, G includes one or two elements from Si and Sn, Q includes Sb, and W includes one or more elements from O, Se, Te, Cl, Br, I, and F.

[0170] Optionally, as an example, sulfide solid electrolyte materials may include Li6PS5Cl, Li6PS5Br, Li 10 GeP2S 12 Li3PS4, Li7P3S 11 One or more of them.

[0171] Optionally, the halide solid electrolyte material may be one or more of Li3YCl6, Li3YBr6, Li3ErCl6, Li3InCl6, and Li3InBr6, including but not limited to.

[0172] Optionally, the oxide solid electrolyte material may include one or more of the following: NASICON type solid electrolyte, LISICON type solid electrolyte, perovskite type solid electrolyte, and garnet type solid electrolyte.

[0173] As an example, oxide solid electrolyte materials may include, but are not limited to, Li5La3Ti2O 12 Li7La3Zr2O 12 Li4Ti5O 12 Li 14 Zn(GeO4)4, LiTi2(PO4)3, Li 1+x Al x Ti 2-x (PO4)3, Li 1+y Al y Ge 2-y One or more of (PO4)3, 0 < x < 2, 0 < y < 2.

[0174] Optionally, the polymer solid electrolyte material can be formed by complexing a polymer matrix material with a lithium salt. Optionally, the polymer matrix material can be one or more of, but not limited to, polyethylene oxide (PEO) and its derivatives, polypropylene oxide (PPO) and its derivatives, polycarbonate (PPC), polyacrylonitrile (PAN), polysiloxane (PDMS), polyvinylidene fluoride (PVDF), and polymethyl methacrylate (PMMA). Optionally, the lithium salt can be one or more of, but not limited to, LiClO4, LiAsF4, LiPF6, LiBF4, LiTFSI, and LiFSI.

[0175] Optionally, the polymer solid electrolyte material may also include an inert filler, which can reduce the crystallinity of the polymer and improve its mechanical properties. Optionally, the inert filler may include, but is not limited to, one or more of TiO2, Al2O3, ZrO2, and SiO2.

[0176] In some embodiments, the electrolyte layer may or may not include a binder, depending on the manufacturing process of the solid-state battery cell. Optionally, the binder may include, but is not limited to, one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, methyl vinyl silicone rubber, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), thermoplastic styrene-butadiene rubber (SBS), isoprene rubber, butadiene rubber (BR), ethyl cellulose, fluororubber, and acrylate rubber.

[0177] In some embodiments, the solid-state battery cell may further include an outer packaging for accommodating the electrode assembly formed by assembling the negative electrode layer, electrolyte layer, and positive electrode layer. The outer packaging may be a rigid shell, such as a hard plastic shell, aluminum shell, or steel shell. The outer packaging may also be a flexible package, such as a pouch. The material of the flexible package may be plastic, such as one or more of aluminum-plastic film, polypropylene, polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0178] [Preparation methods for solid-state battery cells]

[0179] The methods for preparing solid-state battery cells are well known. For example, the assembly methods of solid-state battery cells include, but are not limited to, coin cells, mold cells, hard-case cells, and pouch cells.

[0180] This disclosure also provides a method for preparing porous carbon, which can prepare the porous carbon provided in the embodiments of this disclosure.

[0181] The preparation method of porous carbon includes the following steps: mixing a carbon source and a pore-forming agent under a protective gas atmosphere for pre-carbonization treatment to obtain a porous carbon precursor material; then crushing the obtained porous carbon precursor material and performing carbonization treatment at 1000℃-1600℃ under a protective gas atmosphere to obtain porous carbon with a specific surface area of ​​50 m². 2 / g-500m 2 / g, I of porous carbon D / I G It is 1.68-1.80, I D The Raman spectrum of porous carbon is shown at 1350±50 cm⁻¹. -1 The intensity of peak D at I G The Raman spectrum of porous carbon is shown at 1580±50 cm⁻¹. -1 The intensity of the G peak at that location.

[0182] The carbonization temperature can be between 1000℃ and 1600℃, for example, it can be 1000℃, 1050℃, 1100℃, 1150℃, 1200℃, 1250℃, 1300℃, 1350℃, 1400℃, 1450℃, 1500℃, 1550℃, 1600℃, or any combination of the above values.

[0183] In some embodiments, the carbonization treatment time can be 2h-6h, for example, it can be 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h, 5.8h, 6h, or any range of the above values.

[0184] Adjusting the type of carbon source, pore-forming agent parameters such as particle size or molecular weight, degree of molecular chain folding, the mass ratio of carbon source to pore-forming agent, and the temperature and time of carbonization treatment can regulate the specific surface area, porosity, pore size distribution, and pore volume of porous carbon.

[0185] In some embodiments, the carbon source may include one or more of the following: coal tar, coal pitch, petroleum residue, petroleum pitch, synthetic pitch, anthracite, aliphatic organic compounds, organic compounds containing carbonyl groups, organic compounds containing benzene rings, synthetic resins, epoxy resins, phenolic resins, sucrose, cellulose, lignin, glucose, starch, and gelatin.

[0186] In some embodiments, the pore-forming agent may include one or more of water vapor, potassium hydroxide, sodium hydroxide, calcium hydroxide, calcium oxide, magnesium oxide, magnesium hydroxide, melamine, aluminum oxide, and polymers.

[0187] Optionally, the pore-forming agent may include a polymer, which may be a block copolymer. By adjusting parameters such as the molecular weight and the degree of folding of the molecular chain of the block copolymer, the specific surface area, porosity, pore size distribution and pore volume of the porous carbon can be adjusted.

[0188] In some embodiments, the mass ratio of carbon source to pore-forming agent can be from 1:1 to 1:3.5, for example, it can be 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, 1:3.2, 1:3.5, or any range of the above values.

[0189] In some embodiments, the temperature of the pre-carbonization treatment can be 300°C-600°C, for example, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, or any range of the above values.

[0190] In some embodiments, the pre-carbonization time can be 20 min to 60 min, for example, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, or any range of the above values.

[0191] Example

[0192] The following embodiments describe the disclosure of this disclosure in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0193] Example 1

[0194] Preparation of porous carbon

[0195] A mixture was prepared by mixing varnish-type phenol-formaldehyde resin and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer at a mass ratio of 1:2. The mixture was then heated to 450℃ and held for 25 minutes for pre-carbonization to obtain a porous carbon precursor material. The porous carbon precursor material was then pulverized to the desired particle size and placed in a heating furnace. The heat treatment temperature was set to 1400℃, and the heat treatment lasted for 3 hours to obtain porous carbon. The parameters of the porous carbon are detailed in Table 1.

[0196] Preparation of negative electrode layer

[0197] The porous carbon prepared above was mixed with the binder polyvinylidene fluoride (PVDF) at a mass ratio of 95:5, and N-methylpyrrolidone (NMP) solvent was added. The mixture was stirred thoroughly to obtain an interface layer slurry. The interface layer slurry was coated onto the copper foil of the negative electrode current collector, dried, cold-pressed, cut to a suitable size, and then the tabs were welded to obtain the negative electrode layer. The thickness of the interface layer was 10 μm.

[0198] Preparation of positive electrode layer

[0199] LiNi, the positive electrode active material 0.8 Co 0.1 Mn 0.1 O2, solid electrolyte material Li6PS5Cl, positive electrode conductive agent vapor-grown carbon fiber (VGCF), and positive electrode binder polytetrafluoroethylene (PTFE) are mixed evenly in a mass ratio of 70:26:3:1. The mixture is heated on a heating table at 80°C and rolled back and forth to form a dry positive electrode active material layer. Then, it is combined with the positive electrode current collector aluminum foil hot roller, cut to the appropriate size, and welded with tabs to obtain the positive electrode layer.

[0200] Preparation of electrolyte layer

[0201] The solid electrolyte material Li6PS5Cl and the binder polytetrafluoroethylene (PTFE) were mixed evenly at a mass ratio of 99:1, heated on a heating table at 80°C, and rolled back and forth to form a dry electrolyte layer.

[0202] Preparation of solid-state battery cells

[0203] The negative electrode layer, electrolyte layer and positive electrode layer are stacked in order from bottom to top to obtain the electrode assembly. After being subjected to 600MPa isostatic pressing, the electrode assembly is encapsulated in an aluminum-plastic bag to obtain a soft-pack solid-state battery cell.

[0204] Example 2

[0205] Except for the following differences, the preparation of the pouch solid-state battery cells is the same as in Example 1.

[0206] Preparation of porous carbon

[0207] A mixture was prepared by mixing varnish-type phenol-formaldehyde resin and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer at a mass ratio of 1:2. The mixture was then heated to 450℃ and held for 25 minutes for pre-carbonization to obtain a porous carbon precursor material. The porous carbon precursor material was then pulverized to the desired particle size and placed in a heating furnace. The heat treatment temperature was set to 1450℃, and the heat treatment lasted for 3 hours to obtain porous carbon. The parameters of the porous carbon are detailed in Table 1.

[0208] Example 3

[0209] Except for the following differences, the preparation of the pouch solid-state battery cells is the same as in Example 1.

[0210] Preparation of porous carbon

[0211] A mixture was prepared by mixing varnish-type phenol-formaldehyde resin and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer at a mass ratio of 1:2. The mixture was then heated to 450℃ and held for 25 minutes for pre-carbonization to obtain a porous carbon precursor material. The porous carbon precursor material was then pulverized to the desired particle size and placed in a heating furnace. The heat treatment temperature was set to 1380℃, and the heat treatment lasted for 3 hours to obtain porous carbon. The parameters of the porous carbon are detailed in Table 1.

[0212] Example 4

[0213] Except for the following differences, the preparation of the pouch solid-state battery cells is the same as in Example 1.

[0214] Preparation of porous carbon

[0215] A mixture was prepared by mixing varnish-type phenol-formaldehyde resin and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer at a mass ratio of 1:2. The mixture was then heated to 450℃ and held for 25 minutes for pre-carbonization to obtain a porous carbon precursor material. The porous carbon precursor material was then pulverized to the desired particle size and placed in a heating furnace. The heat treatment temperature was set to 1360℃, and the heat treatment lasted for 3 hours to obtain porous carbon. The parameters of the porous carbon are detailed in Table 1.

[0216] Example 5

[0217] Except for the following differences, the preparation of the pouch solid-state battery cells is the same as in Example 1.

[0218] Preparation of porous carbon

[0219] A mixture was prepared by mixing varnish-type phenol-formaldehyde resin and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer at a mass ratio of 1:2. The mixture was then heated to 450℃ and held for 25 minutes for pre-carbonization to obtain a porous carbon precursor material. The porous carbon precursor material was then pulverized to the desired particle size and placed in a heating furnace. The heat treatment temperature was set to 1350℃ for 3 hours to obtain porous carbon. The parameters of the porous carbon are detailed in Table 1.

[0220] Example 6

[0221] Except for the following differences, the preparation of the pouch solid-state battery cells is the same as in Example 1.

[0222] Preparation of porous carbon

[0223] A mixture was prepared by mixing varnish-type phenol-formaldehyde resin and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer at a mass ratio of 1:2.2. The mixture was then heated to 450℃ and held for 25 minutes for pre-carbonization to obtain a porous carbon precursor material. The porous carbon precursor material was then pulverized to the desired particle size and placed in a heating furnace. The heat treatment temperature was set to 1400℃, and the heat treatment lasted for 3 hours to obtain porous carbon. The parameters of the porous carbon are detailed in Table 1.

[0224] Example 7

[0225] Except for the following differences, the preparation of the pouch solid-state battery cells is the same as in Example 1.

[0226] Preparation of porous carbon

[0227] A mixture was prepared by mixing varnish-type phenol-formaldehyde resin and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer at a mass ratio of 1:2.5. The mixture was then heated to 450℃ and held for 25 minutes for pre-carbonization to obtain a porous carbon precursor material. The porous carbon precursor material was then pulverized to the desired particle size and placed in a heating furnace. The heat treatment temperature was set to 1400℃, and the heat treatment lasted for 3 hours to obtain porous carbon. The parameters of the porous carbon are detailed in Table 1.

[0228] Example 8

[0229] Except for the following differences, the preparation of the pouch solid-state battery cells is the same as in Example 1.

[0230] Preparation of porous carbon

[0231] A mixture was prepared by mixing varnish-type phenol-formaldehyde resin and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer at a mass ratio of 1:1.5. The mixture was then heated to 450℃ and held for 25 minutes for pre-carbonization to obtain a porous carbon precursor material. The porous carbon precursor material was then pulverized to the desired particle size and placed in a heating furnace. The heat treatment temperature was set to 1400℃, and the heat treatment lasted for 3 hours to obtain porous carbon. The parameters of the porous carbon are detailed in Table 1.

[0232] Example 9

[0233] Except for the following differences, the preparation of the pouch solid-state battery cells is the same as in Example 1.

[0234] Preparation of porous carbon

[0235] A mixture was prepared by mixing varnish-type phenol-formaldehyde resin and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer at a mass ratio of 1:3. The mixture was then heated to 450℃ and held for 25 minutes for pre-carbonization to obtain a porous carbon precursor material. The porous carbon precursor material was then pulverized to the desired particle size and placed in a heating furnace. The heat treatment temperature was set to 1400℃, and the heat treatment lasted for 3 hours to obtain porous carbon. The parameters of the porous carbon are detailed in Table 1.

[0236] Example 10

[0237] Except for the following differences, the preparation of the soft-pack solid-state battery cells is the same as that of Comparative Example 1.

[0238] Preparation of porous carbon

[0239] A mixture was prepared by mixing varnish-type phenol-formaldehyde resin and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer at a mass ratio of 1:1.5. The mixture was then heated to 450℃ and held for 25 minutes for pre-carbonization to obtain a porous carbon precursor material. The porous carbon precursor material was then pulverized to the desired particle size and placed in a heating furnace. The heat treatment temperature was set to 1300℃ for 2.8 hours to obtain porous carbon. The parameters of the porous carbon are detailed in Table 1.

[0240] Comparative Example 1

[0241] Except for the following differences, the preparation of the pouch solid-state battery cells is the same as in Example 1.

[0242] Preparation of negative electrode layer

[0243] Commercially available biomass hard carbon and binder polyvinylidene fluoride (PVDF) were mixed at a mass ratio of 95:5, and N-methylpyrrolidone (NMP) was added as a solvent. The mixture was thoroughly stirred to obtain an interface layer slurry. This interface layer slurry was coated onto the copper foil of the negative electrode current collector, dried, cold-pressed, cut to the appropriate size, and then welded with electrode tabs to obtain the negative electrode layer. The thickness of the interface layer was 10 μm. The hard carbon had a near-solid structure with a specific surface area of ​​20 m². 2 / g.

[0244] Comparative Example 2

[0245] Except for the following differences, the preparation of the pouch solid-state battery cells is the same as in Example 1.

[0246] Preparation of porous carbon

[0247] A mixture was prepared by mixing varnish-type phenol-formaldehyde resin and polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer at a mass ratio of 1:2.2. The mixture was then heated to 450℃ and held for 25 minutes for pre-carbonization to obtain a porous carbon precursor material. The porous carbon precursor material was then pulverized to the desired particle size and placed in a heating furnace. The heat treatment temperature was set to 1550℃ for 3.5 hours to obtain porous carbon. The parameters of the porous carbon are detailed in Table 1.

[0248] Performance testing

[0249] (1) First coulombic efficiency test of solid-state battery cell

[0250] At 25°C, solid-state battery cells were charged to 4.3V (vs. Li) at a current density of 0.1C. + / Li), let stand for 10 minutes, then discharge to 2.5V at a current density of 0.1C (vs. Li). + / Li), to obtain the specific capacity of the first charge and the specific capacity of the first discharge.

[0251] The initial coulombic efficiency (%) of a solid-state battery cell = first discharge specific capacity / first charge specific capacity × 100%.

[0252] (2) Rate performance test of solid-state battery cells

[0253] At 25°C, the solid-state battery cells were first charged to 4.3V (vs. Li) at a current density of 0.1C. + / Li), let stand for 10 minutes, then discharge to 2.5V at a current density of 0.1C (vs. Li). + The solid-state battery cell was charged and discharged 5 times, and the resulting capacity was recorded as the discharge specific capacity at a rate of 0.1C. Then, the solid-state battery cell was charged to 4.3V (vs. Li) at a current density of 0.1C. + / Li), let stand for 10 minutes, then discharge at a current density of 2C to 2.5V (vs. Li). + The capacity obtained by 5 cycles of charge and discharge ( / Li) is recorded as the discharge specific capacity at a 2C rate.

[0254] (3) Cyclic performance test of solid-state battery cells

[0255] At 25°C, the solid-state battery cells were first charged to 4.3V (vs. Li) at a current density of 0.5C. + / Li), let stand for 10 minutes, then discharge at a current density of 0.5C to 2.5V (vs. Li). + / Li), the discharge specific capacity at this time is recorded as C1. The solid-state battery cell is cycled 200 times at a current density of 0.5C, and the discharge specific capacity at this time is recorded as C2.

[0256] The capacity retention rate of a solid-state battery cell after 200 cycles at a current density of 0.5C is calculated as C2 / C1 × 100%.

[0257] During the above test, a pressure of 5 MPa was applied to the solid-state battery cell.

[0258] As shown in Table 1, the test results indicate that by using porous carbon as the interface layer of the negative electrode, the specific surface area of ​​the carbon is increased to 50 m². 2 / g-500m 2 / g,I D / I G With a value of 1.68-1.80, solid-state battery cells can achieve high initial coulombic efficiency, good rate performance, and good cycle performance.

[0259] Example 1-1

[0260] Except for the following differences, the preparation of the pouch solid-state battery cells is the same as in Example 1.

[0261] Preparation of negative electrode layer

[0262] The porous carbon prepared above was mixed with polyvinylidene fluoride (PVDF) binder at a mass ratio of 95:5, and N-methylpyrrolidone (NMP) solvent was added. The mixture was stirred thoroughly to obtain an interface layer slurry. The interface layer slurry was coated onto the copper foil of the negative electrode current collector, dried, cold-pressed, cut to a suitable size, and then the tabs were welded to obtain the negative electrode layer. The thickness of the interface layer was 6 μm.

[0263] Examples 1-2

[0264] Except for the following differences, the preparation of the pouch solid-state battery cells is the same as in Example 1.

[0265] Preparation of negative electrode layer

[0266] The porous carbon prepared above was mixed with polyvinylidene fluoride (PVDF) binder at a mass ratio of 95:5, and N-methylpyrrolidone (NMP) solvent was added. The mixture was stirred thoroughly to obtain an interface layer slurry. The interface layer slurry was coated onto the copper foil of the negative electrode current collector, dried, cold-pressed, cut to a suitable size, and then the tabs were welded to obtain the negative electrode layer. The thickness of the interface layer was 15 μm.

[0267] Table 2

[0268] As shown in Table 2, further adjusting the thickness of the interface layer can enable solid-state battery cells to better combine high initial coulombic efficiency, good rate performance, and good cycle performance.

[0269] It should be noted that this disclosure is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this disclosure are included within the technical scope of this disclosure. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, are also included within the scope of this disclosure without departing from the spirit of this disclosure.

Claims

1. A solid-state battery cell, comprising a negative electrode layer, a positive electrode layer, and an electrolyte layer, wherein the electrolyte layer is located between the negative electrode layer and the positive electrode layer, wherein, The negative electrode layer includes a negative electrode current collector and an interface layer located on at least one side of the negative electrode current collector. The interface layer includes porous carbon with a specific surface area of ​​50 m². 2 / g-500m 2 / g, the porous carbon of I D / I G It is 1.68-1.80, I D The Raman spectrum of the porous carbon is at 1350±50 cm⁻¹. -1 The intensity of peak D at I G The Raman spectrum of the porous carbon is at 1580±50 cm⁻¹. -1 The intensity of the G peak at that location.

2. The solid-state battery cell according to claim 1, wherein, The porous carbon I D / I G For 1.71-1.75; and / or, The porous carbon has a specific surface area of ​​100 m². 2 / g-450m 2 / g.

3. The solid-state battery cell according to any one of claims 1-2, wherein, The porosity of the porous carbon is 50%-65%.

4. The solid-state battery cell according to any one of claims 1-3, wherein, The porous carbon has a pore structure including mesoporous structures, and the total volume of the mesoporous structures is 5%-50% of the total pore volume of the porous carbon.

5. The solid-state battery cell according to claim 4, wherein, The total volume of the mesoporous structure is 10%-30% of the total pore volume of the porous carbon.

6. The solid-state battery cell according to any one of claims 1-5, wherein, The porous carbon also includes at least one of microporous or macroporous structures.

7. The solid-state battery cell according to claim 6, wherein, The porous carbon has a pore structure including a microporous structure, and the total volume of the microporous structure is less than 65% of the total pore volume of the porous carbon. And / or, The porous carbon has a pore structure including a macropore structure, and the total volume of the macropore structure is less than 70% of the total pore volume of the porous carbon.

8. The solid-state battery cell according to any one of claims 1-7, wherein, The porous carbon has a pore size range of 1.5 nm to 100 nm; and / or, The porous carbon has an average pore size of 5 nm-15 nm; and / or, The total pore volume of the porous carbon is 0.1 cm³. 3 / g-0.5cm 3 / g.

9. The solid-state battery cell according to claim 8, wherein, The porous carbon has a pore size range of 5 nm to 75 nm; and / or, The porous carbon has an average pore size of 6.5 nm to 12 nm; and / or, The total pore volume of the porous carbon is 0.15 cm³. 3 / g-0.35cm 3 / g.

10. The solid-state battery cell according to any one of claims 1-9, wherein, The porous carbon has a volume distribution particle size Dv50 of 50 nm to 2 μm; and / or, The porous carbon has a particle size distribution (Dv90-Dv10) / Dv50 of 1.5-4; and / or, The compacted density of the porous carbon is 0.75 g / cm³. 3 -0.90g / cm 3 .

11. The solid-state battery cell according to any one of claims 1-10, wherein, The thickness of the interface layer is 1μm-20μm.

12. The solid-state battery cell according to any one of claims 1-11, wherein, The positive electrode layer includes a positive electrode current collector and a positive electrode active material layer located on at least one side of the positive electrode current collector. The positive electrode active material layer includes a solid electrolyte material and a positive electrode active material. The positive electrode active material includes one or more of lithium transition metal oxides and their modified materials, lithium phosphates and their modified materials, lithium titanate, lithium niobate, sulfur, selenium, and tellurium. The solid electrolyte material includes one or more of sulfide solid electrolyte materials, halide solid electrolyte materials, oxide solid electrolyte materials, and polymer solid electrolyte materials; and / or, The electrolyte layer comprises one or more of the following: sulfide solid electrolyte material, halide solid electrolyte material, oxide solid electrolyte material, and polymer solid electrolyte material; and / or, The solid-state battery cell is a metal-free solid-state battery cell without a negative electrode; and / or, When the solid-state battery cell is at 100% SOC, a metal layer exists between the negative electrode current collector and the interface layer.

13. The solid-state battery cell according to any one of claims 1-12, wherein, The NP ratio of the solid-state battery cell is 0.01-0.5, where the NP ratio is the ratio of the negative electrode capacity per unit area to the positive electrode capacity per unit area.

14. A battery device comprising a plurality of solid-state battery cells as described in any one of claims 1-13.

15. An electrical device comprising a solid-state battery cell as described in any one of claims 1-13 or a battery device as described in claim 14.

16. A method for preparing porous carbon according to any one of claims 1-13, comprising the following steps: mixing a carbon source and a pore-forming agent under a protective gas atmosphere for pre-carbonization treatment to obtain a porous carbon precursor material; then crushing the obtained porous carbon precursor material and further carbonizing it under a protective gas atmosphere at 1000℃-1600℃ to obtain porous carbon, wherein the porous carbon has a specific surface area of ​​50 m². 2 / g-500m 2 / g, the porous carbon of I D / I G It is 1.68-1.80, I D The Raman spectrum of the porous carbon is at 1350±50 cm⁻¹. -1 The intensity of peak D at I G The Raman spectrum of the porous carbon is at 1580±50 cm⁻¹. - 1 The intensity of the G peak at that location.

17. The method according to claim 16, wherein, The carbonization treatment time is 2h-6h; and / or, The pre-carbonization treatment temperature is 300℃-600℃; and / or, The pre-carbonization treatment time is 20 min-60 min; and / or, The carbon source includes one or more of the following: coal tar, coal pitch, petroleum residue, petroleum pitch, synthetic pitch, anthracite, aliphatic organic compounds, organic compounds containing carbonyl groups, organic compounds containing benzene rings, synthetic resins, epoxy resins, phenolic resins, sucrose, cellulose, lignin, glucose, starch, and gelatin; and / or, The pore-forming agent includes one or more of the following: water vapor, potassium hydroxide, sodium hydroxide, calcium hydroxide, calcium oxide, magnesium oxide, magnesium hydroxide, melamine, aluminum oxide, and polymers; and / or, The mass ratio of the carbon source to the pore-forming agent is 1:1 to 1:3.5.

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