All-solid-state secondary battery and preparation method therefor, and electric device
Patent Information
- Application Number
- PCT/CN2026/070557
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-20
- Filing Date
- 2026-01-05
- Publication Date
- 2026-08-27
Smart Images
Figure CN2026070557_27082026_PF_FP_ABST
Abstract
Description
All-solid-state secondary batteries, their preparation methods, and electrical devices
[0001] Related applications
[0002] This application claims priority to Chinese patent application No. 202510191643.7, filed on February 20, 2025, the entire contents of which are incorporated herein by reference. Technical Field
[0003] This application relates to the field of battery technology, and in particular to an all-solid-state secondary battery, its preparation method, and an electrical device thereof. Background Technology
[0004] Currently, the mainstream sulfide solid electrolytes used in all-solid-state secondary batteries include lithium germanium phosphate sulfide (LGPS) and silver sulfide germanite. These sulfide solid electrolytes have poor thermal stability at high temperatures compared to fully charged ternary cathode materials, which affects the cycle performance of the battery. Summary of the Invention
[0005] In view of the above problems, this application provides an all-solid-state secondary battery, its preparation method, and an electrical device thereof, aiming to improve the cycle performance of the battery.
[0006] In a first aspect, this application provides an all-solid-state secondary battery, comprising a positive electrode, a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode; the solid electrolyte layer comprises a glass-ceramic mixed-phase sulfide, the glass-ceramic mixed-phase sulfide comprising Li, A, S, and X, wherein A comprises at least one selected from N, P, Sb, As, Bi, Cu, Zn, In, Ge, Sn, Si, Al, Mo, Ti, Mn, V, and W, and X comprises at least one selected from F, Cl, Br, and I; the positive electrode comprises a positive electrode film layer, the positive electrode film layer comprising a ternary positive electrode active material.
[0007] In the technical solution of this application embodiment, the solid electrolyte layer includes a glass-ceramic mixed-phase sulfide. This glass-ceramic mixed-phase sulfide includes a glass phase, which has long-range disorder characteristics, allowing the introduction of a large amount of halogen X. The introduction of halogen X can suppress the release and diffusion of active oxygen in the lattice of the fully charged ternary cathode active material, thereby alleviating the chemical reaction between the fully charged ternary cathode active material and the sulfide electrolyte due to the interdiffusion of sulfur and oxygen elements, and reducing the heat release from the reaction, thus helping to improve thermal stability. Improved thermal stability can effectively suppress side reactions between the ternary cathode active material and the sulfide, maintaining good conductivity and stability at the interface, which is beneficial for the smooth transport of lithium ions, and thus helps to improve the cycle performance of the battery. The glass-ceramic mixed-phase sulfide of this application also includes a ceramic phase, which is a crystalline phase. The crystalline phase has high ionic conductivity, which helps to improve the ionic conductivity of the glass-ceramic mixed-phase sulfide. Increased ionic conductivity can reduce energy loss during charging and discharging, which is beneficial to improving the cycle performance of the battery. Therefore, this application can improve the cycle performance of all-solid-state secondary batteries that use ternary materials as positive electrode active materials and sulfides as solid electrolytes.
[0008] In some embodiments, the glass-ceramic mixed-phase sulfide, in Raman spectroscopy, at 400 cm⁻¹ -1 -430cm -1 There is at least one first characteristic peak between them, the peak area of the first characteristic peak is A1, and the glass-ceramic mixed phase sulfide has a peak area of 370 cm⁻¹. -1 -400cm -1 Between The characteristic peaks and the relationship between A1 and A2 indicate the proportion of the ceramic phase in the glass-ceramic mixed phase sulfide. The relatively low content of the glass phase helps to further improve the ionic conductivity of the glass-ceramic sulfide.
[0009] In some embodiments, in X-ray diffraction patterns using Cu-Kα lines, the glass-ceramic mixed-phase sulfide has diffraction peaks at at least two locations among 20.0°±0.5°, 20.9°±0.5°, 23.6°±0.5°, 27.8°±0.5°, and 29.6°±0.5°; and / or, in differential scanning calorimetry, the glass-ceramic mixed-phase sulfide has at least one exothermic peak between 45°C and 350°C.
[0010] In the technical solution of this application embodiment, the XRD pattern of the glass-ceramic mixed-phase sulfide shows diffraction peaks at at least two locations at the aforementioned positions, indicating the presence of a ceramic phase in the glass-ceramic mixed-phase sulfide, and that the ceramic phase includes at least two types of crystals. The glass-ceramic mixed-phase sulfide exhibits at least one exothermic peak between 45°C and 350°C, indicating that a phase transformation occurs within this temperature range.
[0011] In some embodiments, the glass-ceramic mixed-phase sulfide comprises a ceramic phase, the ceramic phase comprising a chemical formula... At least one of the crystal phases shown, wherein 0 ≤ a < 6, 0 < b < 4.
[0012] In some embodiments, the glass-ceramic mixed-phase sulfide includes sulfides of Li2S, A, and LiX.
[0013] In the technical solution of this application embodiment, Li₂S helps to form ion transport channels. The electrolyte structure constructed with Li₂S can provide better ion conduction performance, enabling lithium ions to be inserted and extracted more efficiently between the electrode and the electrolyte during battery charging and discharging. A-sulfides and Li₂S can jointly construct the basic framework structure of the sulfide solid electrolyte. In the glass-ceramic mixed-phase sulfide, A atoms and S atoms form a network structure through covalent bonds. The network formed by AS bonds provides a stable channel framework for lithium ion transport. LiX is used for X doping of the sulfide; the introduction of halogen X helps to improve the thermal stability between the ternary cathode active material and the sulfide.
[0014] In some embodiments, the molar ratio of Li2S, A sulfide, and LiX is (2-5):(0.67-1.67):1.
[0015] In the technical solution of this application embodiment, when the molar ratio of Li2S, A sulfide, and LiX is within this range, the arrangement between lithium ions in Li2S and S and A ions can be optimized, so that lithium ions have a relatively good transport path in the electrolyte, thereby helping to improve ionic conductivity.
[0016] Lithium ions readily migrate within solid electrolytes, thus contributing to further improvements in the electrolyte's ionic conductivity. Furthermore, the framework structure constructed from PS maintains relative stability of ion transport channels during battery charging and discharging. The relatively large radii of bromide and iodide ions, when doped into sulfide solid electrolytes, distort and expand the electrolyte's lattice structure, thereby increasing the migration channels for lithium ions.
[0017] In some embodiments, the particle size Dv50 of the glass-ceramic mixed-phase sulfide is 0.1 μm-2 μm.
[0018] In the technical solution of this application embodiment, when the particle size Dv50 of the glass-ceramic mixed phase sulfide is between 0.1μm and 2μm, the particle size of the glass-ceramic mixed phase sulfide is relatively small, which matches the small-particle-size single-crystal ternary cathode active material and can form a more continuous electron-lithium ion transport network, which is beneficial to the insertion and extraction of lithium ions on the cathode side. In addition, while ensuring the continuous electron-lithium ion transport network in the composite cathode, the presence of small-particle-size glass-ceramic mixed phase sulfide can increase the proportion of ternary cathode active material in the composite cathode, which is beneficial to improving the volumetric energy density of the all-solid-state battery.
[0019] In some embodiments, the ternary positive electrode active material includes at least one of lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide; and / or, the negative electrode includes a negative electrode film layer, the negative electrode film layer including one of lithium metal and lithium alloy.
[0020] In the technical solutions of this application embodiment, both lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide have high energy densities, which helps to improve the energy of all-solid-state secondary batteries. The halogens in the glass-ceramic mixed-phase sulfide can form a stable halide-containing lithium salt protective layer in situ with lithium in the lithium anode or lithium alloy anode, which can block the continuous reaction between the sulfide and the lithium anode or lithium alloy anode, thus helping to improve the stability of the sulfide and the lithium anode or lithium alloy anode.
[0021] Secondly, this application provides a method for preparing an all-solid-state secondary battery, comprising:
[0022] A positive electrode is provided, the positive electrode comprising a positive electrode film layer comprising a ternary positive electrode active material; a solid electrolyte is provided, the solid electrolyte comprising a glass-ceramic mixed-phase sulfide comprising Li, A, S and X, wherein A comprises at least one selected from N, P, Sb, As, Bi, Cu, Zn, In, Ge, Sn, Si, Al, Mo, Ti, Mn, V, and W, and X comprises at least one selected from F, Cl, Br, and I; a negative electrode is provided; the positive electrode, solid electrolyte, and negative electrode are pressed together to obtain an all-solid-state secondary battery.
[0023] In some embodiments, the step of providing a solid electrolyte includes:
[0024] Under an inert atmosphere, sulfides of Li2S and A and LiX are ground to obtain a mixed powder, and the mixed powder is annealed to obtain a solid electrolyte.
[0025] In the technical solution of this application embodiment, the grinding process can fully mix the raw materials, so that the components can react more effectively during the annealing process, thereby helping to form a sulfide solid electrolyte with a uniform structure.
[0026] In some embodiments, the molar ratio of Li2S, A sulfide, and LiX is (2-5):(0.67-1.67):1.
[0027] In the technical solution of this application embodiment, when the mass ratio of Li2S, A sulfide, and LiX is within this range, the arrangement between lithium ions and S and A ions in Li2S can be optimized, so that lithium ions have a relatively good transport path in the electrolyte, thereby helping to improve ionic conductivity.
[0028] In some embodiments, the step of annealing the mixed powder includes:
[0029] The mixed powder is annealed at 50℃-300℃ for 1h-5h.
[0030] In the technical solution of this application embodiment, the mixed powder can be annealed at 50℃-300℃ to form a glass-ceramic mixed phase, which helps to improve the ionic conductivity of sulfides.
[0031] Thirdly, this application provides an electrical device comprising any of the above-mentioned all-solid-state secondary batteries or all-solid-state secondary batteries prepared by any of the above-mentioned preparation methods.
[0032] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description
[0033] Figure 1 is a schematic diagram of the vehicle structure in some embodiments of this application;
[0034] Figure 2 is an exploded structural diagram of the secondary battery in some embodiments of this application;
[0035] Figure 3 is a schematic diagram of the exploded structure of a single battery cell in some embodiments of this application;
[0036] Figure 4 shows the Raman spectra of glass-ceramic mixed-phase sulfides in some embodiments of this application;
[0037] Figure 5 shows the XRD patterns of glass-ceramic mixed-phase sulfides in some embodiments of this application;
[0038] Figure 6 shows the DSC spectra of glass-ceramic mixed-phase sulfides in some embodiments of this application;
[0039] Figure 7 shows the Raman spectra of glass-ceramic mixed-phase sulfides in some other embodiments of this application;
[0040] Figure 8 shows the XRD patterns of glass-ceramic mixed-phase sulfides in some other embodiments of this application;
[0041] Figure 9 shows the DSC spectra of glass-ceramic mixed-phase sulfides in some other embodiments of this application;
[0042] Figure 10 shows the XRD patterns of glass-ceramic mixed-phase sulfides in some embodiments of this application;
[0043] Figure 11 shows the Raman spectrum of the solid electrolyte in Comparative Example 1;
[0044] Figure 12 shows the DSC spectrum of the solid electrolyte in Comparative Example 1;
[0045] Figure 13 shows the Raman spectrum of the solid electrolyte in Comparative Example 2;
[0046] Figure 14 shows the DSC spectrum of the solid electrolyte in Comparative Example 2.
[0047] Figure description: Vehicle 1000; All-solid-state secondary battery 100, controller 200, motor 300; Housing 10, first part 11, second part 12; Battery cell 20, end cap 21, housing 22, electrode assembly 23. Detailed Implementation
[0048] The following embodiments are only used to illustrate the technical solutions of this application more clearly, and are therefore only examples and should not be used to limit the scope of protection of this application.
[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.
[0050] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.
[0051] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0052] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.
[0053] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces). The term "at least one" refers to one or more.
[0054] Sulfide solid electrolytes react with fully charged ternary cathode materials at high temperatures, producing gas and releasing a large amount of heat, indicating a thermal stability difference between the sulfide solid electrolyte and the ternary cathode active material. This reaction leads to structural damage and capacity decay of the cathode active material, as well as the decomposition of the sulfide solid electrolyte, resulting in decreased ionic conductivity, increased internal resistance, and ultimately, reduced battery cycle performance.
[0055] In some embodiments, a protective layer is constructed between the sulfide solid electrolyte and the positive electrode to prevent direct contact between the sulfide solid electrolyte and the positive electrode material, thereby avoiding side reactions between the sulfide solid electrolyte and the positive electrode. The protective layer is generally divided into an inorganic interface layer and an organic interface layer. Inorganic interface layers are usually harder and more brittle, resulting in poor interfacial contact with the ternary positive electrode, which may increase the battery's interfacial impedance and lead to increased battery polarization. Although organic interface layers have good contact with the positive electrode, their low ionic conductivity and low mechanical strength can also lead to increased battery polarization.
[0056] To address the aforementioned issues, it is advisable to dope and modify the sulfide solid electrolyte to fundamentally reduce the side reactions between sulfides and ternary cathode materials.
[0057] Based on the above considerations, an all-solid-state secondary battery is designed and disclosed, including a positive electrode, a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode; the solid electrolyte layer includes a glass-ceramic mixed-phase sulfide, which includes Li, A, S, and X, where A includes at least one of N, P, Sb, As, Bi, Cu, Zn, In, Ge, Sn, Si, Al, Mo, Ti, Mn, V, and W, and X includes at least one of F, Cl, Br, and I; the positive electrode includes a positive electrode film layer, which includes a ternary positive electrode active material.
[0058] In such all-solid-state secondary batteries, the glass phase of the glass-ceramic mixed-phase sulfide exhibits long-range disorder, allowing for the introduction of a large amount of halogen X. The introduction of halogen X can suppress the release and diffusion of active oxygen in the lattice of the fully charged ternary cathode active material, thereby mitigating the chemical reaction between the fully charged ternary cathode active material and the sulfide electrolyte caused by the interdiffusion of sulfur and oxygen, and reducing the heat release from the reaction, thus contributing to improved thermal stability. Improved thermal stability effectively suppresses side reactions between the ternary cathode active material and the sulfide, maintaining good conductivity and stability at the interface, which is beneficial for smooth lithium-ion transport, thereby improving battery cycle performance. The ceramic phase of the glass-ceramic mixed-phase sulfide has high ionic conductivity, which helps to improve the ionic conductivity of the glass-ceramic mixed-phase sulfide. Increased ionic conductivity reduces energy loss during charging and discharging, further enhancing battery cycle performance.
[0059] The all-solid-state secondary battery disclosed in this application can be used, but is not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can also be composed of the secondary battery disclosed in this application.
[0060] This application provides an electrical device that uses an all-solid-state secondary battery as a power source. The all-solid-state secondary battery can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.
[0061] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.
[0062] Referring to Figure 1, vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Vehicle 1000 has an all-solid-state secondary battery 100 installed inside, which can be located at the bottom, front, or rear of vehicle 1000. The all-solid-state secondary battery 100 can be used to power vehicle 1000; for example, it can serve as the operating power source for vehicle 1000. Vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 controls the all-solid-state secondary battery 100 to supply power to the motor 300, for example, to meet the power needs of vehicle 1000 during startup, navigation, and driving.
[0063] In some embodiments of this application, the all-solid-state secondary battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.
[0064] In some embodiments of this application, the all-solid-state secondary battery 100 can be a single battery cell, a group of battery cells, or a battery pack. Referring to FIG2, taking the all-solid-state secondary battery 100 as a battery pack as an example, the all-solid-state secondary battery 100 can include a housing 10 and a single battery cell 20, with the single battery cell 20 housed within the housing 10. The housing 10 provides a space for accommodating the single battery cell 20, and can adopt various structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, which overlap each other, jointly defining a space for accommodating the single battery cell 20. The second portion 12 can be a hollow structure with one open end, and the first portion 11 can be a plate-like structure, covering the open side of the second portion 12 so that the first portion 11 and the second portion 12 jointly define the accommodating space; alternatively, the first portion 11 and the second portion 12 can both be hollow structures with one open side, with the open side of the first portion 11 covering the open side of the second portion 12. Of course, the box 10 formed by the first part 11 and the second part 12 can be of various shapes, such as a cylinder, a cuboid, etc.
[0065] In the all-solid-state secondary battery 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel connections. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 20 is housed within the casing 10. Alternatively, the all-solid-state secondary battery 100 can also consist of multiple battery cells 20 first connected in series, parallel, or in a mixed configuration to form a battery module, and then these battery modules are connected in series, parallel, or in a mixed configuration to form a whole, which is also housed within the casing 10. The all-solid-state secondary battery 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.
[0066] The battery cell 20 can be cylindrical, flat, cuboid, or other shapes.
[0067] Referring to Figures 3 and 4, the battery cell 20 refers to the smallest unit that makes up the battery. The battery cell 20 includes an end cap 21, a housing 22, an electrode assembly 23, and other functional components.
[0068] End cap 21 refers to a component that covers the opening of housing 22 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 21 can be adapted to the shape of housing 22 to fit it. Optionally, end cap 21 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 21 is not easily deformed under pressure or impact, allowing battery cell 20 to have higher structural strength. Functional components such as electrode terminals can be provided on end cap 21. Electrode terminals can be used for electrical connection with electrode assembly 23 for outputting or inputting electrical energy into battery cell 20. In some embodiments, end cap 21 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of battery cell 20 reaches a threshold. The material of end cap 21 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating element may be provided on the inner side of the end cap 21. The insulating element can be used to isolate the electrical connection components within the housing 22 from the end cap 21 to reduce the risk of short circuits. For example, the insulating element may be made of plastic, rubber, etc.
[0069] The housing 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 23, electrolyte, and other components. The housing 22 and the end cap 21 can be independent components. An opening can be provided on the housing 22, and the end cap 21 can be used to close the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 21 and the housing 22 can be integrated. Specifically, the end cap 21 and the housing 22 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 22, the end cap 21 closes the housing 22. The housing 22 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 23. The material of the housing 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special limitations on this.
[0070] Electrode assembly 23 is the component in the battery cell 20 where electrochemical reactions occur. The casing 22 may contain one or more electrode assemblies 23. The electrode assembly 23 is mainly composed of a positive electrode, a solid electrolyte, and a negative electrode stacked together. The portions of the positive and negative electrodes containing active materials constitute the main body of the electrode assembly, while the portions of the positive and negative electrodes without active materials each constitute a tab. The positive and negative tabs can be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the solid electrolyte, and the tabs connect to the electrode terminals to form a current loop.
[0071] Of course, in some other embodiments, the battery cell 20 can also be directly integrated with the chassis / body.
[0072] According to some embodiments of this application, this application provides an all-solid-state secondary battery, including a positive electrode, a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode; the solid electrolyte layer includes a glass-ceramic mixed-phase sulfide, the glass-ceramic mixed-phase sulfide includes Li, A, S and X, A includes at least one of N, P, Sb, As, Bi, Cu, Zn, In, Ge, Sn, Si, Al, Mo, Ti, Mn, V, W, and X includes at least one of F, Cl, Br, I; the positive electrode includes a positive electrode film layer, the positive electrode film layer includes a ternary positive electrode active material.
[0073] Glass-ceramic mixed-phase sulfides are sulfide materials that simultaneously contain a glassy phase and a ceramic phase (crystalline phase). The ceramic phase has a regular crystal structure, with atoms or ions arranged in a certain periodicity and symmetry within the crystal lattice. This ordered arrangement provides relatively fixed and well-defined conduction pathways for ions, facilitating the rapid migration of lithium ions. This, in turn, helps improve the ionic conductivity of glass-ceramic mixed-phase sulfides. Increased ionic conductivity can reduce energy loss during charging and discharging, thus improving battery cycle performance.
[0074] The glass phase lacks a long-range ordered lattice structure and contains numerous interstitial sites and defects, providing ample space for halogen X to occupy. Therefore, the presence of the glass phase facilitates the introduction of more halogen X. The introduction of halogen X forms a protective film on the surface of the ternary cathode active material, reducing the interdiffusion of transition metal ions in the ternary cathode active material with lithium ions in the electrolyte. This reduces side reactions caused by elemental interdiffusion and helps improve the thermal stability between the sulfide solid electrolyte and the ternary cathode active material. Furthermore, the introduction of halogen X can suppress the release and diffusion of active oxygen in the lattice of the fully charged ternary cathode active material, thereby mitigating the chemical reactions between the fully charged ternary cathode active material and the sulfide electrolyte caused by the interdiffusion of sulfur and oxygen elements, and reducing the heat release from the reaction, thus contributing to improved thermal stability. Improved thermal stability effectively suppresses side reactions between the ternary cathode active material and the sulfide, maintaining good conductivity and stability at the interface, which is conducive to smooth lithium ion transport and thus helps improve battery cycle performance.
[0075] Element A can form a network-like framework structure with element S through covalent bonds, thereby providing a stable channel framework for lithium ion transport, allowing lithium ions to migrate relatively freely within it.
[0076] According to some embodiments of this application, in Raman spectroscopy, glass-ceramic mixed-phase sulfides at 400 cm⁻¹ -1 -430cm -1 The first characteristic peak is present between these two points, with a peak area of A1. The glass-ceramic mixed-phase sulfide has a peak area of 370 cm⁻¹. -1 -400cm -1 There is a second characteristic peak between them. The object is 400cm -1 -430cm -1 The material exhibits characteristic peaks shared by both the glass and ceramic phases. These peaks can be formed solely by crystalline materials or by a combination of crystalline and amorphous materials. There can be one or more characteristic peaks shared by the glass and ceramic phases. When there are multiple characteristic peaks, the area of the first characteristic peak is the sum of the areas of all the peaks. Taking element A as an example, the first characteristic peak is PS4.3- Characteristic peaks.
[0077] Glass-ceramic mixed-phase sulfides at 370 cm -1 -400cm -1 The presence of at least one second characteristic peak between the glass-ceramic mixed-phase sulfides refers to the presence of a second characteristic peak at 370 cm⁻¹. -1 -400cm -1 The second characteristic peak contains characteristic peaks of a glassy phase. These characteristic peaks can be single or multiple. When there are multiple characteristic peaks of the glassy phase, the peak area of the second characteristic peak is the sum of the areas of all the characteristic peaks. Therefore, Raman spectroscopy can be used to determine whether a glassy or ceramic phase exists in a sulfide. Taking P as an example, the second characteristic peak is P₂S₆. 4- Characteristic peaks.
[0078] It should be noted that the first and second characteristic peaks are characteristic peaks of the AS bond. Depending on the A element, the positions of the first and second characteristic peaks will shift, while the X element has no significant effect on the positions of the first and second characteristic peaks.
[0079] 14, 15, 16, 17 or 18, or any integer or non-integer between 2.33 and 19, a low relative content of the glass phase helps to further improve the ionic conductivity of glass ceramic sulfides.
[0080] According to some embodiments of this application, in the X-ray diffraction pattern using Cu-Kα lines, the glass-ceramic mixed-phase sulfide has diffraction peaks at at least two positions among 20.0°±0.5°, 20.9°±0.5°, 23.6°±0.5°, 27.8°±0.5°, and 29.6°±0.5°; and / or, in the differential scanning calorimetry pattern, the glass-ceramic mixed-phase sulfide has at least one exothermic peak between 45°C and 350°C.
[0081] X-ray diffraction (XRD) patterns are generated based on the interaction between X-rays and atoms in crystalline materials. Therefore, the presence of diffraction peaks at at least two locations within the ranges of 20.0°±0.5°, 20.9°±0.5°, 23.6°±0.5°, 27.8°±0.5°, and 29.6°±0.5° in the glass-ceramic mixed-phase sulfide indicates that the glass-ceramic mixed-phase sulfide includes a ceramic phase. The presence of diffraction peaks at at least two locations further indicates that the ceramic phase includes at least two crystalline structures. Thus, XRD can be used to further confirm the glass-ceramic mixed phase.
[0082] Differential scanning calorimetry (DSC) is a technique that uses the same heating or cooling conditions to measure the difference in power between a sample and a reference material (typically a substance that does not exhibit thermal effects within the test temperature range). The power difference reflects the endothermic and exothermic processes of the sample during heating or cooling. Glass-ceramic mixed-phase sulfides exhibit at least one exothermic peak between 45°C and 350°C, indicating a phase transformation within this temperature range. This can be further confirmed by DSC. In some embodiments, the full width at half maximum (FWHM) of the exothermic peak in DSC for glass-ceramic mixed-phase sulfides is greater than 5°C.
[0083] According to some embodiments of this application, the glass-ceramic mixed-phase sulfide includes a ceramic phase, and the ceramic phase includes a chemical formula... At least one of the crystal phases shown, wherein 0 ≤ a < 6, 0 < b < 4.
[0084] For example, the chemical formula of the crystal phase can be Li4AS4X or Li4A2S. 6.5 X, Li4A3S9X, Li5AS 4.5 X, Li5A2S7X, Li4A3S 9.5 X, Li6AS5X, Li6A2S 7.5 X, Li6A3S 10 X、Li7AS 5.5 X, Li7A2S8X, Li7A3S 10.5 X, Li8AS6X, Li8A2S 8.5 X, Li8A3S 11 X、Li9AS 6.5 X, Li9A2S9X, Li9A3S 11.5 X. It should be noted that a and b can be integers or non-integers.
[0085] According to some embodiments of this application, the glass-ceramic mixed-phase sulfide includes sulfides of Li2S, A, and LiX.
[0086] Glass-ceramic mixed-phase sulfides, including Li2S, A sulfides and LiX, refer to the raw materials for preparing glass-ceramic mixed-phase sulfides that include Li2S, A sulfides and LiX.
[0087] Li₂S is one of the main raw materials for preparing glass-ceramic mixed-phase sulfides, which can be used to construct the basic structure of sulfide solid electrolytes. Li₂S facilitates the formation of ion transport channels. In the glass-ceramic mixed-phase structure, lithium ions in Li₂S can interact with other ions (such as S and A). By adjusting the composition of each raw material, lithium ions can have relatively good transport paths in the electrolyte. Therefore, the electrolyte structure constructed with Li₂S can provide better ion conductivity, allowing lithium ions to be inserted and extracted more efficiently between the electrodes and the electrolyte during battery charging and discharging.
[0088] A sulfides refer to S ionic conductors, which, together with Li₂S, can form the basic framework structure of sulfide solid electrolytes. In glass-ceramic mixed-phase sulfides, A atoms and S atoms form a network structure through covalent bonds, and the network formed by AS bonds provides a stable channel framework for lithium ion transport.
[0089] LiX is used to dope sulfides with halogen X, and the introduction of halogen X helps to improve the thermal stability between the ternary cathode active material and the sulfide.
[0090] According to some embodiments of this application, the molar ratio of Li2S, A sulfide, and LiX is (2-5):(0.67-1.67):1.
[0091] For example, the molar ratio of Li₂S, A sulfide, and LiX can be 2:0.67:1, 2:1:1, 2:1.33:1, 2:0.67:1.67, 3:0.67:1, 3:1:1, 3:1.67:1, 4:0.67:1, 4:1:1, 4:1.67:1, 5:0.67:1, 5:1:1, or 5:1.67:1. When the molar ratio of Li₂S, A sulfide, and LiX is within this range, the arrangement of lithium ions with S and A ions in Li₂S can be optimized, resulting in a relatively good transport path for lithium ions in the electrolyte, thereby helping to improve ionic conductivity.
[0092] Li7P2S8Br x I 1-x , Li4PS4Br, Li4PS4I.
[0093] The sulfide structure constructed with P2S5 lowers the activation energy for lithium-ion transport, making it easier for lithium ions to move within the solid electrolyte and thus contributing to improved ionic conductivity. Furthermore, the P2S5-based framework maintains relative stability of the ion transport channels during battery charging and discharging. As lithium ions continuously insert and extract into the electrolyte, stress is generated on the electrolyte structure; the network structure formed by P2S5 resists this stress, reducing ion transport barriers caused by structural deformation and ensuring continuous and stable lithium-ion transport within the electrolyte.
[0094] The bromide and iodide ions in LiBr and LiI have relatively large radii. When doped into sulfide solid electrolytes, they can distort and expand the electrolyte's crystal structure, thereby increasing the migration channels for lithium ions. Moreover, compared to single-component halogen doping, dual-component or multi-component halogen doping can further improve the ionic conductivity of sulfide solid electrolytes.
[0095] According to some embodiments of this application, the particle size Dv50 of the glass-ceramic mixed-phase sulfide is 0.1 μm-2 μm.
[0096] Particle size Dv50 refers to the particle size at which the cumulative volume fraction of particles in a particulate system reaches 50%. For example, the particle size Dv50 of the glass-ceramic mixed-phase sulfide can be 0.1 μm, 0.2 μm, 0.5 μm, 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, or 2 μm. When the particle size Dv50 of the glass-ceramic mixed-phase sulfide is between 0.1 μm and 2 μm, the particle size is relatively small, which, when matched with small-particle-size single-crystal ternary cathode active materials, can form a more continuous electron-lithium-ion transport network, which is beneficial for lithium-ion insertion / extraction on the cathode side. Furthermore, while ensuring a continuous electron-lithium-ion transport network in the composite cathode, the presence of small-particle-size glass-ceramic mixed-phase sulfide can increase the proportion of ternary cathode active materials in the composite cathode, which is beneficial for improving the volumetric energy density of the all-solid-state battery.
[0097] According to some embodiments of this application, the ternary positive electrode active material includes at least one of lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide; and / or, the negative electrode includes a negative electrode film layer, said negative electrode film layer including one of lithium metal and lithium alloy.
[0098] In some embodiments, lithium nickel cobalt manganese oxide includes LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM 333 LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM 523LiNi 0.5 Co 0.25 Mn 0.25 O2(NCM 211 LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM 622 LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM 811 At least one of the following. Lithium nickel cobalt aluminum oxide includes LiNi. 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.
[0099] The aforementioned lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide ternary cathode active materials all have high energy density, which helps to improve the energy of all-solid-state secondary batteries.
[0100] In some embodiments, the lithium alloy includes one of lithium-aluminum alloy, lithium-silicon alloy, lithium-tin alloy, lithium-zinc alloy, lithium-magnesium alloy, and lithium-indium alloy.
[0101] The halogens in the glass-ceramic mixed-phase sulfide can form a stable halide-containing lithium salt protective layer in situ with lithium in the lithium anode or lithium alloy anode. This layer can block the continuous reaction between the sulfide and the lithium anode or lithium alloy anode, thus helping to improve the stability of the sulfide and the lithium anode or lithium alloy anode.
[0102] According to some embodiments of this application, this application also provides a method for preparing an all-solid-state secondary battery, comprising: providing a positive electrode, the positive electrode including a positive electrode film layer, the positive electrode film layer including a ternary positive electrode active material; providing a solid electrolyte, the solid electrolyte including a glass-ceramic mixed-phase sulfide, the glass-ceramic mixed-phase sulfide including Li, A, S and X, A including at least one selected from N, P, Sb, As, Bi, Cu, Zn, In, Ge, Sn, Si, Al, Mo, Ti, Mn, V, W, and X including at least one selected from F, Cl, Br, I; providing a negative electrode; and pressing the positive electrode, solid electrolyte and negative electrode together to obtain an all-solid-state secondary battery.
[0103] In some embodiments, the positive electrode film may optionally include a solid electrolyte, which can improve the conductivity of lithium ions in the positive electrode film. The solid electrolyte in the positive electrode film can be consistent with the electrolyte in the solid electrolyte layer, which helps lithium ion conduction.
[0104] In some embodiments, the positive electrode film may optionally include a conductive agent, which, exemplarily, includes at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
[0105] In some embodiments, the positive electrode film layer may optionally include an adhesive, and exemplaryly, the adhesive includes at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinylidene hexafluorophosphate, ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.
[0106] Typically, the positive electrode also includes a positive current collector, which can be a metal foil or a composite current collector. For example, aluminum foil can be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
[0107] Anodes typically include either pure lithium anodes or lithium alloy anodes. In some embodiments, pure lithium anodes can be obtained by directly using lithium metal foil; lithium metal can also be deposited on the surface of a current collector to form an anode through electrochemical deposition; or lithium metal can be heated and evaporated, depositing onto a substrate material to form a thin-film lithium anode. Lithium alloy anodes can be obtained by melting and mixing lithium metal and alloying elements at high temperature, followed by cooling and shaping; or by ball milling lithium metal powder and alloying element powder; or by rolling lithium metal and alloys; or by synthesizing lithium alloy anodes through chemical reactions in solution or other media.
[0108] According to some embodiments of this application, the step of providing a solid electrolyte includes: grinding Li2S, A sulfides and LiX into a mixed powder under an inert atmosphere, and annealing the mixed powder to obtain a solid electrolyte.
[0109] The inert atmosphere can be nitrogen, argon, or helium. Sulfur in Li₂S and A sulfides has strong reducing properties and is easily oxidized in air. Therefore, treatment under an inert atmosphere can prevent oxidation of the raw materials.
[0110] Grinding the sulfides of Li2S and A, as well as LiX, allows for thorough mixing of the raw materials. This enables the components to react more effectively during annealing, thereby helping to form a sulfide solid electrolyte with a uniform structure.
[0111] According to some embodiments of this application, the molar ratio of Li₂S, A sulfides, and LiX is (2-5):(0.67-1.67):1. When the molar ratio of Li₂S, A sulfides, and LiX is within this range, the arrangement of lithium ions in Li₂S with S and A ions can be optimized, resulting in a relatively good transport path for lithium ions in the electrolyte, thereby helping to improve ionic conductivity.
[0112] According to some embodiments of this application, the step of annealing the mixed powder includes annealing the mixed powder at 50°C-300°C for 1-5 hours.
[0113] For example, the annealing temperature can be 50°C, 80°C, 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, 220°C, 240°C, 260°C, 280°C, or 300°C, and the annealing time can be 1 hour, 2 hours, 3 hours, 4 hours, or 5 hours. Annealing the mixed powder at 50°C-300°C can form a glass-ceramic mixed phase, which helps to improve the ionic conductivity of the sulfide.
[0114] According to some embodiments of this application, this application also provides an electrical device, including any of the above-described all-solid-state secondary batteries or all-solid-state secondary batteries prepared by any of the above-described preparation methods.
[0115] Example
[0116] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.
[0117] Example 1
[0118] [Glass-ceramic mixed-phase sulfide solid electrolyte]
[0119] Under a nitrogen atmosphere, Li₂S:P₂S₅:LiBr:LiI was mixed in a molar ratio of 3:1:0.5:0.5, and then transferred to a ball mill jar and ball-milled for 24 h to obtain a mixed powder with a particle size Dv₅₀ of 500 nm. The mixed powder was annealed at 200 °C for 5 h, and after annealing, a glass-ceramic mixed-phase sulfide solid electrolyte was obtained.
[0120] Raman spectroscopy was performed on the glass-ceramic mixed-phase sulfide solid electrolyte using a Renishaw-in via Qontor instrument. The testing conditions were: a 532 nm laser with a power of 0.5 mW was used under an argon atmosphere, and the wavenumber range was 100 cm⁻¹. -1 -3200cm -1 The Raman spectrum of the glass-ceramic mixed-phase sulfide solid electrolyte is shown in Figure 4. It can be seen that its Raman spectrum at 430 cm⁻¹ is... -1 The first characteristic peak is located at 380 cm⁻¹, and the peak area A1 of the first characteristic peak is 160242. -1 It has a second characteristic peak, and the peak area A2 of the second characteristic peak is 9415.97.
[0121] XRD analysis was performed on the glass-ceramic mixed-phase sulfide solid electrolyte using a Bruker-D8 advance instrument. The testing conditions were as follows: Cu-Kα radiation was used. The 2θ range was tested from 10° to 50° with a step size of 0.02°. The XRD pattern of the glass-ceramic mixed-phase sulfide solid electrolyte is shown in Figure 5, which shows diffraction peaks at 20.9°±0.5° and 27.8°±0.5°.
[0122] DSC tests were performed on the glass-ceramic mixed-phase sulfide solid electrolyte using a Netzsch-DSC 300CAliris instrument. The test conditions were as follows: under an argon atmosphere, the temperature was increased from 35℃ to 460℃ at a rate of 10℃ / min. The resulting DSC spectrum is shown in Figure 6, which shows an exothermic peak at 290℃.
[0123] [All-solid-state rechargeable battery]
[0124] All the following operations are performed under an argon atmosphere.
[0125] The ternary cathode active material LiNi was weighed out according to a mass ratio of 70:28:2. 0.8 Co 0.1 Mn 0.1 O2, glass-ceramic mixed-phase sulfide powder, and conductive carbon were mixed and ground for 30 minutes to obtain composite cathode powder.
[0126] Lithium metal and indium metal were weighed out at a mass ratio of 3:97 (the molar ratio of Li:In was 35:65) and repeatedly rolled to alloy them. The alloyed metals were then cut into round pieces with a diameter of 10 mm to obtain the lithium alloy anode.
[0127] 100 mg of a glass-ceramic mixed-phase sulfide was first pressed into shape under a pressure of 100 MPa to form the electrolyte layer. The aforementioned composite positive electrode powder was then uniformly sprinkled onto one side of the electrolyte layer and pressed into shape under a pressure of 360 MPa. An alloy negative electrode was added to the other side of the electrolyte layer, and an external pressure of 100 MPa was applied to the battery.
[0128] Example 2
[0129] Unlike Example 1, the annealing temperature of the mixed powder in this example is 160°C, while the rest is the same as in Example 1.
[0130] Example 3
[0131] Unlike Example 1, the annealing temperature of the mixed powder in this example is 50°C, while the rest is the same as in Example 1.
[0132] Example 4
[0133] Unlike Example 1, the annealing temperature of the mixed powder in this example is 300°C, while the rest is the same as in Example 1.
[0134] Example 5
[0135] Unlike Example 1, the annealing time of the mixed powder in this example is 1 hour, while the rest is the same as in Example 1.
[0136] Example 6
[0137] Unlike Example 1, the raw materials for the glass-ceramic mixed-phase sulfide solid electrolyte in this example include Li2S, P2S5, and LiI, with Li2S:P2S5:LiI = 3:1:1. The rest is the same as in Example 1.
[0138] Example 7
[0139] Unlike Example 1, the raw materials for the glass-ceramic mixed-phase sulfide solid electrolyte in this example include Li2S, P2S5, WS2, S, LiBr, and LiI, with Li2S:P2S5:WS2:S:LiBr:LiI = 3:0.99:0.02:0.02:0.5:0.5. The rest is the same as in Example 1.
[0140] The Raman spectrum of the glass-ceramic mixed-phase sulfide solid electrolyte in this embodiment is shown in Figure 7. It can be seen that it exhibits a high Raman spectrum at 420 cm⁻¹. -1 fixtures Diffraction peaks were observed at 23.8°±0.5° and 29.2°±0.5°, respectively.
[0141] Figure 9 shows the DSC spectrum of the glass-ceramic mixed-phase sulfide solid electrolyte in this embodiment, which shows that it has exothermic peaks at 220℃ and 270℃.
[0142] Example 8
[0143] Unlike Example 1, the raw materials for the glass-ceramic mixed-phase sulfide solid electrolyte in this example include Li2S, P2S5, WS2, S, LiBr, and LiI, with Li2S:P2S5:WS2:S:LiBr:LiI = 3:0.95:0.1:0.05:0.5:0.5. The rest is the same as in Example 1.
[0144] Example 9
[0145] Unlike Example 1, the raw materials for the glass-ceramic mixed-phase sulfide solid electrolyte in this example include Li2S, P2S5, Sb2S3, S, LiBr, and LiI, with Li2S:P2S5:Sb2S3:S:LiBr:LiI = 3:0.99:0.01:0.02:0.5:0.5. The rest is the same as in Example 1.
[0146] The XRD pattern of the glass-ceramic mixed-phase sulfide solid electrolyte in this embodiment is shown in Figure 10. It can be seen that it has diffraction peaks at 19.8°±0.5°, 23.9°±0.5°, and 29.3°±0.5°.
[0147] Example 10
[0148] Unlike Example 1, the raw materials for the glass-ceramic mixed-phase sulfide solid electrolyte in this example include Li2S, P2S5, Sb2S3, S, LiBr, and LiI, with Li2S:P2S5:Sb2S3:S:LiBr:LiI = 3:0.95:0.05:0.1:0.5:0.5. The rest is the same as in Example 1.
[0149] Comparative Example 1
[0150] Unlike Example 1, the solid electrolyte in this comparative example is silver sulfide germanite Li6PS5Cl, whose crystal structure is different from that in Example 1. Li6PS5Cl has a cubic silver sulfide germanite crystal structure, while the rest is the same as in Example 1.
[0151] The Raman spectrum of Li6PS5Cl in Comparative Example 1 is shown in Figure 11, and the DSC spectrum is shown in Figure 12. It can be seen that Li6PS5Cl in Comparative Example 1 does not belong to glass-ceramic mixed phase sulfides.
[0152] Comparative Example 2
[0153] Unlike Example 1, the solid electrolyte in this comparative example is Li. 10 GeP2S 12 The rest is the same as in Example 1.
[0154] In Comparative Example 2, the solid electrolyte is Li 10 GeP2S 12 The Raman spectrum is shown in Figure 13, and the DSC spectrum is shown in Figure 14. It can be seen that the solid electrolyte in Comparative Example 2 is Li. 10 GeP2S 12 It does not belong to glass-ceramic mixed-phase sulfides.
[0155] Performance testing
[0156] Ionic conductivity: 120 mg of glass-ceramic mixed-phase sulfide solid electrolyte was weighed and placed into a molded battery, and pressed into a sheet under a pressure of 380 MPa; under the conditions of a test frequency range of 0.1 Hz-1 MHz and an amplitude of 10 mV, the shaped sulfide solid electrolyte was tested.
[0157] Thermal stability of sulfide and ternary cathode materials: A glass-ceramic mixed-phase sulfide solid electrolyte and ternary cathode active material NCM 811 The mixture is thoroughly mixed; then DSC testing is performed on it under the following conditions: in an argon atmosphere, the temperature is increased from 35℃ to 460℃ at a rate of 10℃ / min to obtain the DSC spectrum. The area ΔH of the exothermic peak is the total heat generated by the sulfide and the ternary cathode material.
[0158] Stability of sulfide and pure lithium anode: A lithium metal symmetric battery was assembled according to the structure of "lithium metal-glass-ceramic mixed-phase sulfide solid electrolyte-lithium metal": 120 mg of glass-ceramic mixed-phase sulfide solid electrolyte was weighed and placed into a mold battery, then pressed under a pressure of 380 MPa. Lithium sheets were added to both sides to form a lithium metal symmetric battery. At 0.1 mA·cm⁻¹ -1 At a current density of , a constant current discharge was performed on a lithium symmetric battery, and the cycle duration when a short circuit occurred in the lithium symmetric battery was recorded.
[0159] Cycle performance: The secondary battery was charged at room temperature at a rate of 0.2C to a voltage of 4.2V, and then discharged at a rate of 0.2C to a voltage of 2.8V. The reversible capacity was measured as C0. This charging and discharging process was repeated until the discharge capacity C of a certain cycle was achieved. n When / C0 ≤ 80%, the total number of iterations represents the loop performance. n It is the reversible capacity at the nth cycle.
[0160] Test Results
[0161] The test results of Examples 1-10 and Comparative Examples 1-2 are shown in Table 1.
[0162] Table 1. Test results from Examples 1-10 and Comparative Examples 1-2
[0163] As shown in Table 1, the total heat generation in the embodiments of this application is lower than that in the comparative example, the cycle duration of the lithium symmetric battery under short circuit is longer than that in the comparative example, and the cycle performance of the battery is better than that in the comparative example. This indicates that the glass-ceramic mixed-phase sulfide solid electrolyte layer, the ternary cathode material, and the lithium anode of this application all have high stability, which helps to improve the cycle performance of the battery.
[0164] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
Claims
1. An all-solid-state secondary battery, comprising a positive electrode, a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode, wherein, The solid electrolyte layer comprises a glass-ceramic mixed-phase sulfide, which includes Li, A, S and X. The A includes at least one of N, P, Sb, As, Bi, Cu, Zn, In, Ge, Sn, Si, Al, Mo, Ti, Mn, V and W, and the X includes at least one of F, Cl, Br and I. The positive electrode includes a positive electrode film layer, and the positive electrode film layer includes a ternary positive electrode active material.
2. The all-solid-state secondary battery as described in claim 1, wherein, In Raman spectroscopy, the glass-ceramic mixed-phase sulfide exhibits a light intensity at 400 cm⁻¹. -1 -430cm -1 There is at least one first characteristic peak between them, the peak area of the first characteristic peak is A1, and the glass-ceramic mixed phase sulfide has a peak area of 370 cm⁻¹. -1 -400cm -1 There is at least one second characteristic peak between them, and the peak area of the second characteristic peak is A2; A1 and A2 satisfy:
3. The all-solid-state secondary battery as described in claim 1, wherein, In the X-ray diffraction pattern using Cu-Kα lines, the glass-ceramic mixed-phase sulfide exhibits diffraction peaks at at least two locations among 20.0°±0.5°, 20.9°±0.5°, 23.6°±0.5°, 27.8°±0.5°, and 29.6°±0.5°; and / or, In the differential scanning calorimetry (DSC) spectrum, the glass-ceramic mixed-phase sulfide has at least one exothermic peak between 45°C and 350°C.
4. The all-solid-state secondary battery according to any one of claims 1 to 3, wherein, The glass-ceramic mixed-phase sulfide comprises a ceramic phase, which includes the chemical formula... At least one of the crystal phases shown, wherein 0 ≤ a < 6, 0 < b < 4.
5. The all-solid-state secondary battery as described in claim 4, wherein, The glass-ceramic mixed-phase sulfides include sulfides of Li2S, A, and LiX.
6. The all-solid-state secondary battery as described in claim 5, wherein, The molar ratio of Li2S, A sulfide, and LiX is (2-5):(0.67-1.67):
1.
7. The all-solid-state secondary battery according to any one of claims 4 to 6, wherein, The chemical formula of the ceramic phase is: Where 0 ≤ x ≤ 1.
8. The all-solid-state secondary battery according to any one of claims 1 to 7, wherein, The particle size Dv50 of the glass-ceramic mixed phase sulfide is 0.1 μm-2 μm.
9. The all-solid-state secondary battery according to any one of claims 1 to 8, wherein, The ternary cathode active material includes at least one of lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide. And / or, the negative electrode includes a negative electrode film layer, which includes lithium metal or a lithium alloy.
10. A method for preparing an all-solid-state secondary battery, wherein, include: A positive electrode is provided, the positive electrode including a positive electrode film layer, the positive electrode film layer including a ternary positive electrode active material; A solid electrolyte is provided, the solid electrolyte comprising a glass-ceramic mixed-phase sulfide comprising Li, A, S and X, wherein A comprises at least one of N, P, Sb, As, Bi, Cu, Zn, In, Ge, Sn, Si, Al, Mo, Ti, Mn, V and W, and X comprises at least one of F, Cl, Br and I; Provide the negative electrode; The positive electrode, solid electrolyte, and negative electrode are pressed together to obtain an all-solid-state secondary battery.
11. The method for preparing an all-solid-state secondary battery as described in claim 10, wherein, The step of providing the solid electrolyte includes: Under an inert atmosphere, sulfides of Li2S and A and LiX are ground to obtain a mixed powder, and the mixed powder is annealed to obtain a solid electrolyte.
12. The method for preparing an all-solid-state secondary battery as described in claim 11, wherein, The molar ratio of Li2S, A sulfide, and LiX is (2-5):(0.67-1.67):
1.
13. The method for preparing an all-solid-state secondary battery as described in claim 11, wherein, The step of annealing the mixed powder includes: The mixed powder is annealed at 50℃-300℃ for 1h-5h.
14. An electrical appliance, wherein, Includes the all-solid-state secondary battery as described in any one of claims 1 to 9 or the all-solid-state secondary battery prepared by the preparation method described in any one of claims 10 to 13.