Composite positive pole piece and preparation method thereof, all-solid-state battery and electric equipment

Abstract

The invention discloses a composite positive pole piece and a preparation method thereof, an all-solid-state battery and electric equipment. The composite positive pole piece comprises a positive current collector and a positive active material layer; in the positive electrode active material layer, in the direction far away from the positive electrode current collector, the content of the positive electrode active material coated with the additive is in a trend of increasing, the content of the positive electrode active material not coated with the additive is in a trend of decreasing, and the content of the sulfide electrolyte coated with the additive is in a trend of decreasing; the content of the uncoated sulfide electrolyte is increased; the additive comprises a lithium salt containing a fluorine element and / or a boron element. Therefore, in the charging and discharging process of the all-solid-state battery, the composite positive pole piece can directly form a uniform interface stable layer in situ on a positive active material / sulfide electrolyte interface in the composite positive pole and an interface between the whole positive pole piece and an electrolyte layer, so that an interface side reaction between the positive pole and an electrolyte under a high-voltage condition is inhibited; therefore, the electrochemical performance of the battery is improved.

Description

Technical Field

[0001] This application relates to the field of batteries, specifically to composite positive electrode sheets and their preparation methods, all-solid-state batteries, and electrical devices. Background Technology

[0002] Currently, solid-state batteries equipped with solid electrolytes are better suited to the future development needs of electric vehicles and large-scale energy storage due to their superior safety and the potential to achieve high energy density. All-solid-state batteries can be mainly divided into polymer-based all-solid-state batteries, organic-inorganic composite all-solid-state batteries, and sulfide-based all-solid-state batteries. Among them, sulfide-based all-solid-state batteries have received widespread attention in the industry due to their high room-temperature ionic conductivity and good mechanical properties.

[0003] The large-scale application of sulfide-based all-solid-state batteries still faces many significant challenges. Among these, the composite cathode material layer, composed of the cathode active material, sulfide electrolyte, and conductive agent, is the decisive factor affecting the electrochemical performance of sulfide-based solid-state batteries. However, side reactions at the interface between the cathode active material and the sulfide solid-state electrolyte, as well as space charge layer effects, make it difficult for sulfide-based all-solid-state batteries to meet commercial requirements in terms of rate performance and cycle performance.

[0004] Therefore, current composite cathode sheets and their preparation methods, all-solid-state batteries, and electrical devices still need improvement. Summary of the Invention

[0005] This application aims to at least partially alleviate or resolve at least one of the aforementioned problems.

[0006] In one aspect of this application, a composite positive electrode sheet is proposed. In some embodiments of this application, the composite positive electrode sheet includes a positive current collector and a positive active material layer, the positive active material layer being located on at least one surface of the positive current collector; the positive active material layer includes an additive-coated positive active material, an uncoated positive active material, an additive-coated sulfide electrolyte, and an uncoated sulfide electrolyte; in the positive active material layer, along the direction away from the positive current collector, the content of the additive-coated positive active material shows an increasing trend, the content of the uncoated positive active material shows a decreasing trend, the content of the additive-coated sulfide electrolyte shows a decreasing trend, and the content of the uncoated sulfide electrolyte shows an increasing trend; the additive includes a lithium salt containing fluorine and / or boron. Therefore, during the charging and discharging process of the all-solid-state battery, the composite positive electrode can directly form a uniform interface stabilization layer in situ at the interface between the positive active material / sulfide electrolyte inside the composite positive electrode and at the interface between the entire positive electrode and the electrolyte layer, so as to suppress the interface side reaction between the positive electrode and the electrolyte under high voltage conditions, thereby improving the electrochemical performance of the battery.

[0007] In another aspect of this application, a method for preparing a composite positive electrode sheet is proposed. In some embodiments of this application, the method for preparing the composite positive electrode sheet includes: providing a positive current collector; forming a positive active material layer on at least one surface of the positive current collector, wherein the positive active material layer comprises an additive-coated positive active material, an uncoated positive active material, an additive-coated sulfide electrolyte, and an uncoated sulfide electrolyte; in the positive active material layer, along a direction away from the positive current collector, the content of the additive-coated positive active material shows an increasing trend, the content of the uncoated positive active material shows a decreasing trend, the content of the additive-coated sulfide electrolyte shows a decreasing trend, and the content of the uncoated sulfide electrolyte shows an increasing trend; the additive includes a lithium salt containing fluorine and / or boron. Therefore, during the charging and discharging process of all-solid-state batteries, the composite cathode prepared by this method can directly form a uniform interface stabilization layer in situ at the interface between the cathode active material / sulfide electrolyte and the entire interface between the cathode and the electrolyte layer, thereby suppressing the interface side reactions between the cathode and the electrolyte under high voltage conditions and thus improving the electrochemical performance of the battery.

[0008] In another aspect, this application proposes an all-solid-state battery. In some embodiments of this application, the all-solid-state battery includes a positive electrode, a solid electrolyte layer, and a negative electrode. The positive electrode includes the composite positive electrode sheet described above or a composite positive electrode sheet prepared using the methods described above. Therefore, this battery possesses all the features and advantages of the composite positive electrode sheet described above, which will not be repeated here.

[0009] In another aspect of this application, an electrical device is proposed. In some embodiments of this application, the electrical device includes the all-solid-state battery described above. Therefore, this electrical device possesses all the features and advantages of the all-solid-state battery described above, which will not be repeated here. Attached Figure Description

[0010] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0011] Figure 1 A schematic diagram of the structure of a composite positive electrode sheet according to an embodiment of this application is shown;

[0012] Figure 2 A schematic diagram of the structure of a composite positive electrode sheet according to another embodiment of this application is shown;

[0013] Figure 3 A schematic diagram of the structure of a composite positive electrode sheet according to yet another embodiment of this application is shown;

[0014] Figure 4 A schematic diagram of the structure of a composite positive electrode sheet according to yet another embodiment of this application is shown;

[0015] Figure 5 This shows a schematic diagram of the contact structure between different particles in the positive electrode sheet;

[0016] Figure 6 This shows a schematic diagram of the structure of the positive electrode and the solid electrolyte layer in the related technology;

[0017] Figure 7 A schematic diagram of the structure of a composite positive electrode and a solid electrolyte layer according to an embodiment of this application is shown.

[0018] Explanation of reference numerals in the attached figures:

[0019] 100: Composite positive electrode sheet; 110: Positive current collector; 120: Positive active material layer; 121: First sublayer; 122: Second sublayer; 123: Third sublayer; 200: Solid electrolyte layer; 10: Positive active material; 20: Sulfide electrolyte; 30: First coating layer; 40: Second coating layer; 50: Interfacial side reaction material layer; 11: First positive active material; 12: First sulfide electrolyte; 13: Third coating layer; 14: Second positive active material; 15: Fourth coating layer; 16: Second sulfide electrolyte. Detailed Implementation

[0020] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0021] This application is based on the inventor's discoveries and understanding of the following facts and problems:

[0022] To address the issues inherent in all-solid-state batteries, surface coating of the cathode material can be used to improve electrochemical performance. Currently, commonly used cathode coating systems primarily utilize oxygen-based inorganic compounds with low electronic conductivity but some ionic conductivity. However, these coatings still fall short of current requirements in terms of ionic conductivity, electrochemical stability window, and cost. Furthermore, coating the surface of the cathode active material with materials exhibiting low electronic conductivity can also affect electron transport within the composite cathode. Additionally, side reactions between the cathode and the sulfide electrolyte can occur at the interface between the entire composite cathode electrode and the sulfide electrolyte layer. However, due to the inherent thermal stability of the electrode, traditional cathode material coating methods are difficult to apply directly to the electrode. While gas-phase reaction methods can achieve uniform coating across the entire electrode interface, their high cost hinders large-scale commercial applications.

[0023] The inventors of this application employ additives to coat the positive electrode active material and sulfide electrolyte. By designing the content variation patterns of the additive-coated positive electrode active material, the additive-coated sulfide electrolyte, the uncoated positive electrode active material, and the uncoated sulfide electrolyte, the additives can decompose under high voltage during battery charging. This allows a uniform (B and / or F enriched) interface stabilization layer to be formed in situ at the interface between the positive electrode active material / sulfide electrolyte and the entire interface between the positive electrode sheet and the electrolyte layer within the composite positive electrode during charging. This suppresses interfacial side reactions between the positive electrode and the electrolyte under high voltage conditions, while still ensuring sufficient electron transport pathways within the composite positive electrode, thereby improving the electrochemical performance of the battery.

[0024] Therefore, in one aspect of this application, a composite positive electrode is proposed. In some embodiments of this application, reference is made to... Figures 1 to 4 The composite positive electrode 100 may include a positive current collector 110 and a positive active material layer 120, wherein the positive active material layer 120 is located on at least one surface of the positive current collector 110.

[0025] In some embodiments of this application, the positive electrode active material layer 120 may include an additive-coated positive electrode active material, an uncoated positive electrode active material, an additive-coated sulfide electrolyte, and an uncoated sulfide electrolyte. In the positive electrode active material layer 120, along the direction away from the positive electrode current collector 110, the content of the additive-coated positive electrode active material tends to increase, the content of the uncoated positive electrode active material tends to decrease, the content of the additive-coated sulfide electrolyte tends to decrease, and the content of the uncoated sulfide electrolyte tends to increase. The additive may include lithium salts containing fluorine and / or boron. Therefore, by designing variations in the content of substances in the positive electrode active material layer, the additives can decompose under high voltage during battery charging. This allows a uniform (B and / or F enriched) interface stabilization layer to be formed in situ at the interface between the positive electrode active material / sulfide electrolyte and the entire interface between the positive electrode sheet and the electrolyte layer during charging of the all-solid-state battery. This suppresses interfacial side reactions between the positive electrode and the electrolyte under high voltage, while still ensuring sufficient electron transport pathways within the composite positive electrode, thereby improving the electrochemical performance of the battery.

[0026] It should be noted that the term "content" in this application refers to mass content.

[0027] It should also be noted that the terms "showing an increasing trend" and "showing a decreasing trend" in this application can include a variety of different situations. The following explanation uses "showing an increasing trend" as an example, while "showing a decreasing trend" can be understood in a similar way.

[0028] In some embodiments, "showing an increasing trend" can refer to the fact that the content of a certain component can gradually increase along the direction away from the positive electrode current collector.

[0029] In other embodiments, "showing an increasing trend" may refer to the fact that the content of a certain component can increase in a gradient along the direction away from the positive electrode current collector. For example, the positive electrode active material layer may include multiple sublayers, and the content of a certain component in any one sublayer is greater than the content of that component in a sublayer closer to the positive electrode current collector.

[0030] In some other embodiments, "showing an increasing trend" may mean that the content of a certain component can remain constant within a certain thickness range along the direction away from the positive electrode current collector. For example, the positive electrode active material layer may include at least three sublayers, and the content of a certain component may be the same in two adjacent sublayers.

[0031] In some embodiments of this application, the additive may include at least one of lithium dioxaborate (LiBOB), lithium difluorooxaborate (LiDFOB), lithium difluorophosphate (LiPO2F2), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and lithium bis(monofluoromalonic acid)borate (LiBFMB). The above additives can decompose under high temperature, high pressure, or current to generate a stable interface layer with certain ionic conductivity and low electronic conductivity. This is beneficial for suppressing interfacial side reactions between the positive electrode active material and the sulfide dielectric interface inside the composite positive electrode under high pressure conditions, as well as between the positive electrode sheet and the sulfide electrolyte layer, thereby improving the electrochemical performance of the all-solid-state battery.

[0032] In some embodiments of this application, the additive may be LiBOB, LiDFOB, LiPO2F2, LiFSI, LiTFSI, or LiBFMB. In other embodiments of this application, the additive may include two or more of LiBOB, LiDFOB, LiPO2F2, LiFSI, LiTFSI, and LiBFMB.

[0033] In some embodiments of this application, the additives coating the sulfide electrolyte and the additives coating the positive electrode active material may be the same. In other embodiments of this application, the additives coating the sulfide electrolyte and the additives coating the positive electrode active material may be different.

[0034] It should be noted that in this application, "coating" can refer to full coating or partial coating. Taking the positive electrode active material coated with additives as an example, the positive electrode active material particles can be completely coated by the additives, or only a portion of the positive electrode active material particles can be covered by the additives.

[0035] In some embodiments of this application, the thickness of the additive coating layer in the additive-coated positive electrode active material can be 1 nm-20 nm. For example, the thickness of the coating layer can be 1 nm, 3 nm, 5 nm, 7 nm, 10 nm, 12 nm, 15 nm, 20 nm, etc. A coating layer thickness within the above range is more conducive to forming a uniform interface stabilizing layer between the additive-coated positive electrode active material and the uncoated sulfide electrolyte, suppressing side reactions under high voltage conditions, thereby further improving the electrochemical performance of the all-solid-state battery.

[0036] In some embodiments of this application, the thickness of the additive coating layer in the additive-coated sulfide electrolyte can be 1 nm to 20 nm. For example, the thickness of the coating layer can be 1 nm, 2 nm, 4 nm, 8 nm, 10 nm, 13 nm, 16 nm, 20 nm, etc. This is more conducive to the formation of a uniform interfacial stabilizing layer between the uncoated positive electrode active material and the additive-coated sulfide electrolyte, suppressing side reactions under high voltage, and thus further improving the electrochemical performance of the all-solid-state battery.

[0037] In some embodiments of this application, the mass of the additive in the positive electrode active material coated with the additive can be 0.1%-10% of the mass of the positive electrode active material before coating. For example, the mass of the additive can be 0.1%, 0.5%, 0.8%, 1%, 4%, 6%, 8%, 10%, etc., of the mass of the positive electrode active material before coating. Therefore, the additive content described above can form a thin coating layer on the surface of the positive electrode active material. During charge and discharge, the additive can decompose to form components with certain ion-conducting properties but poor electron-conducting properties, thereby helping to suppress side reactions between the positive electrode active material and the electrolyte.

[0038] In some embodiments of this application, the mass of the additive in the additive-coated sulfide electrolyte can be 0.1%-10% of the mass of the sulfide electrolyte before coating. For example, the mass of the additive can be 0.1%, 0.3%, 0.6%, 0.9%, 2%, 5%, 7%, 10%, etc., of the mass of the sulfide electrolyte before coating. Therefore, the above-mentioned amounts of additive can form a thin coating layer on the surface of the sulfide electrolyte. During charge and discharge, the additive can decompose to form components with good ion conduction properties but poor electron conduction properties, thereby better suppressing side reactions between the electrolyte and the positive electrode active material.

[0039] In some embodiments of this application, reference is made to Figure 1 and Figure 3 A positive electrode active material layer 120 is disposed on one surface of the positive electrode current collector 110. In other embodiments of this application, reference is made to... Figure 2 and Figure 4 A positive electrode active material layer 120 is provided on both surfaces of the positive electrode current collector 110.

[0040] In some embodiments of this application, reference is made to Figure 1 and Figure 2The positive electrode active material layer 120 may include a first sublayer 121 and a second sublayer 122, wherein the first sublayer 121 is located between the positive electrode current collector 110 and the second sublayer 122; in the first sublayer 121, the positive electrode active material is an uncoated first positive electrode active material, and the sulfide electrolyte is an additive-coated first sulfide electrolyte; in the second sublayer 122, the positive electrode active material is an additive-coated second positive electrode active material, and the sulfide electrolyte is an uncoated second sulfide electrolyte. Thus, at the interface between the positive electrode active material and the sulfide electrolyte in the first and second sublayers, and at the interface between the first and second sublayers, a uniform and stable interface layer is formed in situ by the additive, suppressing interfacial side reactions between the positive electrode active material and the electrolyte in the composite positive electrode, thereby improving the electrochemical performance of the battery.

[0041] The following detailed explanation, with reference to the accompanying drawings, explains why the composite positive electrode of this application can improve the electrochemical performance of all-solid-state batteries.

[0042] Figure 5 Figure (a) shows the case where the uncoated sulfide electrolyte 20 and the uncoated positive electrode active material 10 are in direct contact. In this case, the ion conduction performance of the interface between the two is poor, but it still has a certain electron conduction capability. Under these circumstances, interfacial side reactions are prone to occur, forming an interfacial side reaction material layer 50, which degrades battery performance. This situation should be avoided as much as possible, both on the side of the positive electrode active material layer closest to the positive electrode current collector and on the side furthest from the positive electrode current collector.

[0043] Figure 5 Figure (b) shows the case where the uncoated sulfide electrolyte 20 and the additive-coated positive electrode active material 10 are in direct contact. The additive forms a first coating layer 30 on the surface of the positive electrode active material 10. In this case, the interface between the positive electrode active material 10 and the sulfide electrolyte 20 has a certain ion-conducting ability, but the electron-conducting performance is poor. On the side of the positive electrode active material layer away from the positive electrode current collector, there can be more coated positive electrode active material and uncoated sulfide electrolyte in direct contact, which can avoid the generation of side reactions.

[0044] Figure 5 Figure (c) shows the case where the additive-coated sulfide electrolyte 20 and the uncoated positive electrode active material 10 are in direct contact. The additive forms a second coating layer 40 on the surface of the sulfide electrolyte 20. In this case, the interface also has a certain ion conduction ability, but the electron conduction performance is poor. On the side of the positive electrode active material layer near the positive electrode current collector, there can be more uncoated positive electrode active material and coated sulfide electrolyte in direct contact, which can avoid the generation of side reactions.

[0045] On the side of the positive electrode active material layer closest to the positive electrode current collector, there can still be a significant number of uncoated positive electrode active material particles in contact with each other. In this case, the particles can provide ample electron transport pathways, increasing the electrochemical activity of the battery. On the side of the positive electrode active material layer furthest from the current collector, the presence of more coated positive electrode active material particles helps mitigate side reactions at the interface between the composite positive electrode layer and the solid electrolyte layer, further increasing the battery's electrochemical activity.

[0046] In some embodiments of this application, reference is made to Figure 3 and Figure 4 The positive electrode active material layer 120 further includes at least one third sublayer 123, which is located between the first sublayer 121 and the second sublayer 122. The third sublayer 123 includes a third positive electrode active material coated with additives, a fourth positive electrode active material that is not coated, a third sulfide electrolyte coated with additives, and a fourth sulfide electrolyte that is not coated.

[0047] In some embodiments of this application, the positive electrode active material layer 120 includes a first sublayer 121, a third sublayer 123, and a second sublayer 122. In the third sublayer 123, based on the total mass of the positive electrode active material (including coated and uncoated) and the sulfide electrolyte (including coated and uncoated), the mass contents of the additive-coated positive electrode active material, the uncoated positive electrode active material, the additive-coated sulfide electrolyte, and the uncoated sulfide electrolyte can be 45%, 45%, 5%, and 5%, respectively.

[0048] It should be noted that the first positive electrode active material, the second positive electrode active material, the third positive electrode active material, and the fourth positive electrode active material can be the same or different; the first sulfide electrolyte, the second sulfide electrolyte, the third sulfide electrolyte, and the fourth sulfide electrolyte can be the same or different; and the additives forming each coating layer can be the same or different.

[0049] In some embodiments of this application, the positive electrode active material layer 120 may include a first sublayer 121, a second sublayer 122, and at least two third sublayers 123. The closer the third sublayer 123 is to the second sublayer 122, the higher the mass content of the positive electrode active material coated with the additive and the lower the mass content of the uncoated positive electrode active material. The lower the mass content of the sulfide electrolyte coated with the additive and the higher the mass content of the uncoated sulfide electrolyte.

[0050] By designing the above-mentioned changes in component content, electron transport within the positive electrode active material can be better ensured, while side reactions at the interface between the positive electrode active material and the sulfide electrolyte, as well as at the interface between the positive electrode active material layer and the electrolyte layer, can be better avoided. During charging and discharging, the additives can decompose into components that conduct ions but have poor electron conduction performance, thereby improving the electrochemical performance of the battery.

[0051] In some embodiments, in the positive electrode active material layer, along the direction away from the positive electrode current collector, the content gradient of the positive electrode active material coated with the additive increases, the content gradient of the uncoated positive electrode active material decreases, the content gradient of the sulfide electrolyte coated with the additive decreases, and the content gradient of the uncoated sulfide electrolyte increases.

[0052] In some related technologies, such as Figure 6 As shown, the positive electrode active material layer is located between the positive electrode current collector 110 and the solid electrolyte layer 200. The sulfide electrolyte 20 (small particles) in the positive electrode active material layer are all uncoated, while the positive electrode active material 10 (large particles) are all coated with additives. The additives form a first coating layer 30 on the surface of the positive electrode active material 10. In this case, there will be a lot of coated positive electrode active material particles in direct contact in the entire positive electrode active material layer, which will result in poor conductivity of the internal electronic properties of the positive electrode active material layer and is not conducive to improving the electrochemical performance of the battery.

[0053] In some embodiments of this application, reference is made to Figure 7 The positive electrode active material layer is located between the positive electrode current collector 110 and the solid electrolyte layer 200. The positive electrode active material layer includes a first sublayer 121 and a second sublayer 122. The first sublayer 121 is close to the positive electrode current collector 110. In this layer, the first positive electrode active material 11 (larger particles) is uncoated, and the first sulfide electrolyte 12 (smaller particles) is coated with additives. The additives form a third coating layer 13 on the surface of the first sulfide electrolyte 12. In this case, more positive electrode active material particles are in direct contact, resulting in better electronic conductivity. The coated sulfide electrolyte and the positive electrode active material are in close contact. When the active material particles are in direct contact, the interface conducts ions but has poor electronic properties and is not prone to side reactions. The second sublayer 122 is close to the solid electrolyte layer 200. In this layer, the second positive electrode active material 14 (with larger particles) is coated with additives, and the additives form a fourth coating layer 15 on the surface of the second positive electrode active material 14. The second sulfide electrolyte 16 (with smaller particles) is uncoated. In this case, when the coated positive electrode active material comes into contact with the uncoated sulfide electrolyte, it is not easy for side reactions to occur. Side reactions are also not easy to occur between the second sublayer 122 and the solid electrolyte layer 200.

[0054] It should be noted that the additives forming the first coating layer 30 and the second coating layer 40 can be the same or different; the additives forming the third coating layer 13 and the fourth coating layer 15 can be the same or different; the first positive electrode active material 11 and the second positive electrode active material 14 can be the same or different; and the first sulfide electrolyte 12 and the second sulfide electrolyte 16 can be the same or different.

[0055] The additives are materials with high ionic conductivity and low electronic conductivity. When these additives are used to coat the positive electrode active material, if the coated positive electrode active material particles are in direct contact, the electronic conductivity of the composite positive electrode will be limited. Therefore, on the side closer to the positive electrode current collector, the coating primarily consists of a sulfide electrolyte. This suppresses side reactions between the positive electrode and the sulfide electrolyte while ensuring sufficient electron transport pathways within the composite positive electrode. On the side farther from the positive electrode current collector, i.e., closer to the solid electrolyte layer (sulfide electrolyte layer), the coating primarily consists of the positive electrode active material, to achieve a stable interface when in contact with the sulfide electrolyte layer.

[0056] In some embodiments of this application, in any two sublayers of the positive electrode active material layer, the thickness of the sublayer farther from the positive electrode current collector is less than or equal to the thickness of the sublayer closer to the positive electrode current collector. This is more conducive to ensuring sufficient electron transport pathways inside the composite positive electrode.

[0057] In some embodiments, the positive electrode active material layer 120 is composed of a first sublayer 121 and a second sublayer 122, and the thickness of the second sublayer 122 may be less than the thickness of the first sublayer 121. In other embodiments, the positive electrode active material layer 120 is composed of a first sublayer 121 and a second sublayer 122, and the thickness of the second sublayer 122 may be equal to the thickness of the first sublayer 121.

[0058] In some embodiments, the positive electrode active material layer consists of at least two sublayers, with the thickness of each sublayer decreasing in the direction away from the positive electrode current collector.

[0059] In some embodiments of this application, the mass content of the positive electrode active material can be 75%-89.5% based on the total mass of the positive electrode active material layer. For example, the mass content of the positive electrode active material can be 75%, 80%, 82%, 85%, 87%, 89.5%, etc. A higher content of positive electrode active material in the positive electrode active material layer ensures that the positive electrode has a higher capacity.

[0060] In some embodiments of this application, the positive electrode active material can be a ternary positive electrode material. In some embodiments, the positive electrode active material may include NCM811 (a ternary material LiNi with a molar ratio of Ni, Co, and Mn of 8:1:1). 0.8 Co 0.1 Mn0.1 O2), Ni88 ternary cathode material (LiNi) 0.88 Co x Mn 0.12-x O2, 0 < x < 0.12), Ni90 ternary cathode material (LiNi 0.9 Co y Mn 0.1-y At least one of O2 (0 < y < 0.1). In some specific embodiments of this application, the positive electrode active material can be a high-voltage positive electrode material such as NCM811, Ni88 ternary positive electrode material, or Ni90 ternary positive electrode material. In other specific embodiments of this application, the positive electrode active material can include at least two of NCM811, Ni88 ternary positive electrode material, and Ni90 ternary positive electrode material. It should be noted that these positive electrode materials can be undoped or doped and modified, and their surface can have a conductive coating layer or not.

[0061] In some embodiments of this application, the sulfide electrolyte may include a glass-ceramic Li-PS system electrolyte (e.g., 75Li2S·5P2S3·20P2S5), or a sulfide germanium ore Li6PS5X (where X can be a halogen such as Cl, Br, or I, specifically Li). 5.5 PS 4.5 Cl 1.5 The system electrolyte, lithium germanium phosphorus sulfur Li 10 GeP2S 12 At least one of the (LGPS) system electrolytes. Adding a sulfide electrolyte to the positive electrode active material layer can optimize ion transport channels, improve lithium-ion conductivity, and reduce the internal resistance of the battery, thereby improving the charge and discharge performance of the battery; the aforementioned sulfide electrolyte can also form a relatively stable interface with the positive electrode active material, reducing interfacial side reactions, thereby improving the cycle stability of the battery.

[0062] In some embodiments of this application, the positive current collector may include aluminum foil. In some specific embodiments of this application, the positive current collector may be carbon-coated aluminum foil.

[0063] In some embodiments of this application, the positive electrode active material layer may further include a binder and a conductive agent.

[0064] In some embodiments of this application, the binder in the positive electrode active material layer may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), nitrile rubber (NBR, e.g., hydrogenated nitrile rubber HNBR), polyacrylate, polyacrylic acid (PAA), alkyl cellulose, and polyethylene oxide (PEO).

[0065] In some embodiments of this application, the mass content of the binder can be 0.48%-2% based on the total mass of the positive electrode active material layer. For example, the mass content of the binder can be 0.48%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, etc. Therefore, the binder content described above can provide good adhesion, bonding the various particles in the positive electrode active material layer together and firmly bonding the positive electrode active material layer to the positive electrode current collector, thereby improving the stability of the positive electrode sheet.

[0066] In some embodiments of this application, the conductive agent in the positive electrode active material layer may include at least one of carbon black (e.g., acetylene black, Super P, etc.), carbon nanotubes, and graphene. Adding the above-mentioned conductive agent is beneficial to improving the conductivity of the positive electrode active material layer, thereby further improving the electrochemical performance of the battery.

[0067] In some embodiments of this application, the mass content of the conductive agent can be 0.48%-2% based on the total mass of the positive electrode active material layer. For example, the mass content of the conductive agent can be 0.48%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, etc. This is beneficial to improving the conductivity of the positive electrode, thereby improving the electrochemical performance of the battery.

[0068] In some embodiments of this application, the positive electrode active material layer may include 75%-89.5% by mass of positive electrode active material (including additive-coated and uncoated), 0.48%-2% by mass of binder, 0.48%-2% by mass of conductive agent, and the balance being sulfide electrolyte (including additive-coated and uncoated).

[0069] In this application, the contact state between the coated and uncoated materials does not need to be specially controlled, and the components in the electrode can be detected by means of XPS, SEM and other methods.

[0070] In another aspect of this application, a method for preparing a composite positive electrode sheet is proposed. In some embodiments of this application, the method for preparing a composite positive electrode sheet may include the following steps:

[0071] S100: Provides positive current collector.

[0072] In some embodiments of this application, the positive current collector may include aluminum foil. In some specific embodiments of this application, the positive current collector may be carbon-coated aluminum foil.

[0073] S200: A layer of positive electrode active material is formed on at least one surface of the positive electrode current collector.

[0074] In the embodiments of this application, the positive electrode active material layer includes an additive-coated positive electrode active material, an uncoated positive electrode active material, an additive-coated sulfide electrolyte, and an uncoated sulfide electrolyte. In the positive electrode active material layer, along the direction away from the positive electrode current collector, the content of the additive-coated positive electrode active material shows an increasing trend, the content of the uncoated positive electrode active material shows a decreasing trend, the content of the additive-coated sulfide electrolyte shows a decreasing trend, and the content of the uncoated sulfide electrolyte shows an increasing trend. The additive includes a lithium salt containing fluorine and / or boron.

[0075] By designing variations in component content, on the side closer to the positive electrode current collector, more uncoated positive electrode active material particles are in direct contact, providing ample electron transport paths. The interface between the uncoated positive electrode active material and the coated sulfide electrolyte has some ion-conducting ability but poor electron-conducting performance, effectively preventing side reactions. On the side farther from the positive electrode current collector, the interface between the coated positive electrode active material and the uncoated sulfide electrolyte also has some ion-conducting ability but poor electron-conducting performance, again effectively preventing side reactions. During charging, the all-solid-state battery forms a uniform interface stabilization layer in situ at the positive electrode active material / sulfide electrolyte interface within the composite positive electrode sheet and at the interface between the entire positive electrode sheet and the electrolyte layer. This suppresses interface side reactions between the positive electrode and the electrolyte under high voltage conditions. Simultaneously, sufficient electron transport paths still exist within the composite positive electrode, thereby improving the battery's electrochemical performance.

[0076] In some embodiments of this application, the mass content of the positive electrode active material can be 75%-89.5% based on the total mass of the positive electrode active material layer.

[0077] In some embodiments of this application, forming a positive electrode active material layer on at least one surface of the positive electrode current collector may include the following steps:

[0078] S210: The first sulfide electrolyte is coated with an additive to obtain the first sulfide electrolyte coated with the additive. The first sulfide electrolyte coated with the additive, the uncoated first positive electrode active material, the first conductive agent and the first binder are mixed evenly to obtain a first mixture. The first mixture is placed on the surface of the positive electrode current collector and pressed into a sheet to obtain the first sublayer.

[0079] In some embodiments of this application, in the step of coating the first sulfide electrolyte with an additive, the mass of the additive can be 0.1%-10% of the mass of the first sulfide electrolyte before coating. For example, the mass of the additive can be 0.1%, 0.5%, 1%, 5%, 7%, 10%, etc., of the mass of the first sulfide electrolyte before coating. This facilitates the formation of a thinner coating layer on the surface of the sulfide electrolyte.

[0080] In some embodiments of this application, the method of coating the first sulfide electrolyte with an additive may include: mixing the additive and the first sulfide electrolyte uniformly, and then ball-milling and / or mechanically fusing the mixture using a ball mill and / or a mechanical fusion machine to coat the surface of the first sulfide electrolyte with the additive. This allows the additive to be deposited on the particle surface of the sulfide electrolyte. During the mixing process, the material is simultaneously subjected to extrusion and shear forces, resulting in a thin and uniform coating of the additive on the surface of the sulfide electrolyte material particles.

[0081] In some embodiments of this application, the process of coating the first sulfide electrolyte can be carried out in an inert atmosphere.

[0082] In some embodiments of this application, a ball mill can be used to ball mill the additive and the first sulfide electrolyte, so that the additive is coated on the surface of the first sulfide electrolyte. In some specific embodiments of this application, when using a ball mill for coating, the rotation speed can be 1000rpm-10000rpm, which is beneficial to forming a thin and uniform additive coating layer on the surface of the sulfide electrolyte, and the material is not easily decomposed during the mixing process.

[0083] In some embodiments of this application, a mechanical fusion machine can be used to mechanically fuse the additive and the first sulfide electrolyte. Mixing with a mechanical fusion machine can also form a thin and uniform coating layer on the surface of the first sulfide electrolyte.

[0084] In some embodiments of this application, the additive may include at least one of lithium dioxaborate, lithium difluorooxaborate, lithium difluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium bis(monofluoromalonic acid)borate.

[0085] In some embodiments of this application, the positive electrode active material may include a ternary positive electrode material, for example, the positive electrode active material may include NCM811 (LiNi). 0.8 Co 0.1 Mn 0.1 O2), Ni88 ternary cathode material (LiNi) 0.88 Co x Mn 0.12-x O2, 0 < x < 0.12), Ni90 ternary cathode material (LiNi 0.9 Co y Mn 0.1-y At least one of O2, 0 < y < 0.1).

[0086] In some embodiments of this application, the sulfide electrolyte may include at least one of the following: Li-PS system electrolyte, silver-germanium sulfide system electrolyte, and lithium-germanium-phosphorus-sulfur system electrolyte.

[0087] Regarding the first conductive agent and the first binder in the first sublayer, please refer to the materials of the conductive agent and binder in the positive electrode active material layer mentioned above, which will not be repeated here.

[0088] S220: The second positive electrode active material is coated with an additive to obtain the additive-coated second positive electrode active material. The additive-coated second positive electrode active material, the uncoated second sulfide electrolyte, the second conductive agent and the second binder are mixed evenly to obtain a second mixture. The second mixture is placed on the side of the first sublayer away from the positive electrode current collector and pressed into a sheet to obtain the second sublayer.

[0089] In some embodiments of this application, in the step of coating the second positive electrode active material with an additive, the mass of the additive can be 0.1%-10% of the mass of the second positive electrode active material before coating. For example, the mass of the additive can be 0.1%, 0.5%, 1%, 5%, 7%, 10%, etc., of the mass of the second positive electrode active material before coating. This facilitates the formation of a thinner coating layer on the surface of the positive electrode active material.

[0090] In some embodiments of this application, the method of coating the second positive electrode active material with an additive may include: mixing the additive and the second positive electrode active material uniformly, and ball milling and / or mechanically fusing the mixture using a ball mill and / or a mechanical fusion machine to coat the surface of the positive electrode active material with the additive. This allows the additive to be deposited on the particle surface of the positive electrode active material. During the mixing process, the material is simultaneously subjected to extrusion and shear forces, resulting in a thin and uniform coating of the additive on the particle surface of the positive electrode active material.

[0091] In some embodiments of this application, the process of coating the second positive electrode active material can be carried out in an inert atmosphere.

[0092] In some embodiments of this application, a ball mill or a mechanical fusion machine can be used to coat the second positive electrode active material. In some embodiments of this application, when using a ball mill for coating, the rotation speed can be 1000rpm-10000rpm. This is beneficial for forming a thin and uniform additive coating layer on the surface of the positive electrode active material, and the material is not easily decomposed during the process, thus maintaining good chemical stability.

[0093] In some embodiments of this application, forming a positive electrode active material layer on at least one surface of the positive electrode current collector before forming a second sublayer may further include the step of forming at least one third sublayer. Forming a third sublayer includes the following steps:

[0094] The third positive electrode active material is coated with an additive to obtain the additive-coated third positive electrode active material. The method and parameters for coating the third positive electrode active material can refer to the method and parameters for coating the second positive electrode active material mentioned earlier, and will not be repeated here.

[0095] The third sulfide electrolyte was coated with an additive to obtain an additive-coated third sulfide electrolyte. The method and parameters for coating the third sulfide can be referred to the method and parameters for coating the first sulfide electrolyte, and will not be repeated here.

[0096] In some embodiments of this application, the third positive electrode active material coated with additives and the third sulfide electrolyte coated with additives in the third sublayer can also be obtained by processing the mixture of additives and the third positive electrode active material, and the mixture of additives and the fourth sulfide electrolyte, using a ball mill and / or a mechanical fusion machine.

[0097] The additive-coated third positive electrode active material, the uncoated fourth positive electrode active material, the additive-coated third sulfide electrolyte, the uncoated fourth sulfide electrolyte, the third conductive agent, and the third binder are mixed evenly to obtain a third mixture. The third mixture is placed on the side of the first sublayer away from the positive electrode current collector and pressed into a sheet to obtain the third sublayer.

[0098] In some embodiments of this application, a third sublayer may be formed on the side of the first sublayer away from the positive current collector before the second sublayer is formed. In other embodiments of this application, at least two third sublayers may be formed on the side of the first sublayer away from the positive current collector before the second sublayer is formed. Regardless of the number of third sublayers formed, the following conditions must be met: in the positive electrode active material layer, along the direction away from the positive current collector, the content of the positive electrode active material coated with the additive shows an increasing trend, the content of the uncoated positive electrode active material shows a decreasing trend, the content of the sulfide electrolyte coated with the additive shows a decreasing trend, and the content of the uncoated sulfide electrolyte shows an increasing trend.

[0099] In some embodiments of this application, before forming the second sublayer, at least one third sublayer may be formed on the side of the first sublayer away from the positive current collector. In the positive active material layer, in the direction away from the positive current collector, the content gradient of the positive active material coated with the additive increases, the content gradient of the uncoated positive active material decreases, the content gradient of the sulfide electrolyte coated with the additive decreases, and the content gradient of the uncoated sulfide electrolyte increases.

[0100] Regarding the second conductive agent and second binder in the second sublayer, and the third conductive agent and third binder in the third sublayer, please refer to the materials of the conductive agent and binder in the positive electrode active material layer mentioned above, which will not be repeated here.

[0101] It should be noted that the additives in each coating layer can be the same or different; the first conductive agent, the second conductive agent, and the third conductive agent can be the same or different; the first binder, the second binder, and the third binder can be the same or different; the first positive electrode active material, the second positive electrode active material, the third positive electrode active material, and the fourth positive electrode active material can be the same or different; and the first sulfide electrolyte, the second sulfide electrolyte, the third sulfide electrolyte, and the fourth sulfide electrolyte can be the same or different.

[0102] The thickness relationship of each sublayer has been explained above and will not be repeated here.

[0103] In another aspect, this application proposes an all-solid-state battery. In some embodiments of this application, the all-solid-state battery includes a positive electrode, a solid electrolyte layer, and a negative electrode, with the solid electrolyte layer located between the positive and negative electrodes. The positive electrode comprises the composite positive electrode sheet described above or a composite positive electrode sheet prepared using the methods described above. Therefore, this battery is less prone to side reactions during charging and discharging and exhibits excellent electrochemical performance.

[0104] In some embodiments of this application, the material of the solid electrolyte layer may include at least one of oxide electrolyte, sulfide electrolyte, and polymer electrolyte.

[0105] In some embodiments of this application, the oxide electrolyte may include at least one of LATP, LLZO, LLTO, etc. In some embodiments of this application, the sulfide electrolyte may include a glass-ceramic Li-PS system electrolyte (e.g., 75Li₂S·5P₂S₃·20P₂S₅), or argentite Li₆PS₅X (where X can be a halogen such as Cl, Br, or I, specifically Li). 5.5 PS 4.5 Cl 1.5 The system electrolyte, lithium germanium phosphorus sulfur Li 10 GeP2S 12 At least one of the (LGPS) system electrolytes. In some embodiments of this application, the polymer electrolyte may include at least one of PEO, PVDF, and PAN.

[0106] In some embodiments of this application, the particle size of the solid electrolyte in the solid electrolyte layer can be 1 nm-5 μm. In some specific embodiments, micron-sized solid electrolyte materials can be used.

[0107] In some embodiments of this application, the negative electrode active material used can be any of the lithium-intercalation / deintercalation-capable negative electrode active materials commonly used by those skilled in the art. For example, it can be selected from one or more of carbon materials, tin alloys, silicon alloys, silicon, tin, and germanium, or it can be metallic lithium, lithium-indium alloys, etc. The carbon material can be one or more of non-graphitized carbon, graphite, or carbon or pyrolytic carbon obtained by high-temperature oxidation of polyacetylenic polymers, coke, sintered organic polymers, and activated carbon.

[0108] In some embodiments of this application, after assembling the positive electrode, solid electrolyte, and negative electrode into an all-solid-state battery, it can be pre-cycled three times, preferably at high temperature (30-60°C) and low rate (0.01-0.1C), so that the additives are oxidized and decomposed at the positive electrode / sulfide interface, thereby forming a uniform interface stabilizing layer in situ to suppress the interface side reactions between the positive electrode and the sulfide electrolyte under high voltage, thereby improving the electrochemical performance of the battery.

[0109] In another aspect of this application, an electrical device is proposed. In some embodiments of this application, the electrical device may include the all-solid-state battery described above. Therefore, the electrical device possesses all the features and advantages of the all-solid-state battery described above, which will not be repeated here.

[0110] In some embodiments of this application, the electrical equipment may be a vehicle (e.g., an electric bicycle, an electric car, a hybrid vehicle, etc.), a portable electronic device (e.g., a smartphone, a laptop, a tablet, etc.), a robot, an energy storage system, etc.

[0111] In summary, the composite cathode design proposed in this application for all-solid-state batteries, through variations in component content, enables the formation of a uniform interfacial stabilizing layer in situ at the interface between the positive electrode active material / sulfide electrolyte and the interface between the entire cathode sheet and the electrolyte layer during charging. This suppresses interfacial side reactions between the positive electrode and the electrolyte under high voltage conditions while ensuring sufficient electron transport pathways within the composite cathode. Consequently, the electrochemical performance of the all-solid-state battery assembled using the aforementioned composite cathode sheet is significantly improved. This composite cathode design for all-solid-state batteries requires no expensive or complex fabrication processes / methods, is simple and economical, and has a wide range of applications.

[0112] The present application will be described below through specific embodiments. Those skilled in the art will understand that the specific embodiments below are merely illustrative and do not limit the scope of the present application in any way. Furthermore, in the following embodiments, unless otherwise specified, the materials and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the later embodiments, conditions and methods known in the art can be used for processing.

[0113] Example 1

[0114] Using 90 parts by weight of LiNi 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P were used as materials for the composite cathode I, and 90 parts by weight of LiDFOB-coated LiNi were used. 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of uncoated LPSC (Li 5.5 PS 4.5 Cl 1.5 A composite cathode was prepared by using 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P as materials for composite cathode II; LPSC (Li 5.5 PS 4.5 Cl 1.5 A solid electrolyte layer was prepared, and a mold battery was assembled with Li / In as the negative electrode. The battery performance was then tested.

[0115] The manufacturing process is as follows: ① The materials of composite cathode I and composite cathode II are thoroughly mixed; a certain amount of composite cathode I powder is weighed and placed in a pressing mold, and pressed into a sheet on the surface of the cathode current collector using cold pressing technology; then a certain amount of composite cathode II powder is weighed and placed in a pressing mold, and composite cathode II powder is pressed on the surface of the composite cathode I sheet to obtain a double-layer composite cathode sheet; ② LPSC solid electrolyte is prepared; ③ Matching Li / In anode to assemble the mold battery.

[0116] In Example 1, the LiDFOB coating content in the LiDFOB-coated LPSC was 1% (the mass of LiDFOB was 1% of the mass of the LPSC before coating), and the LiDFOB-coated LiNi... 0.88 Co 0.08 Mn 0.04The LiDFOB coating content in O2 is 1% (the mass of LiDFOB is the same as the mass of LiNi before coating). 0.88 Co 0.08 Mn 0.04 The thickness of composite cathode I is 6.75 μm, the thickness of composite cathode II is 0.75 μm, and the thickness ratio of composite cathode I to composite cathode II is 9:1.

[0117] Example 2

[0118] Using 90 parts by weight of LiNi 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P were used as materials for the composite cathode I, and 90 parts by weight of LiDFOB-coated LiNi were used. 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 A composite cathode was prepared by using 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P as materials for composite cathode II; LPSC (Li 5.5 PS 4.5 Cl 1.5 A solid electrolyte layer was prepared, and a mold battery was assembled with Li / In as the negative electrode. The battery performance was then tested.

[0119] The manufacturing process is as follows: ① The materials of composite cathode I and composite cathode II are thoroughly mixed; a certain amount of composite cathode I powder is weighed and placed in a pressing mold, and pressed into a sheet on the surface of the cathode current collector using cold pressing technology; then a certain amount of composite cathode II powder is weighed and placed in a pressing mold, and composite cathode II powder is pressed on the surface of the composite cathode I sheet to obtain a double-layer composite cathode sheet; ② LPSC solid electrolyte is prepared; ③ Matching Li / In anode to assemble the mold battery.

[0120] In Example 2, the LiDFOB coating content in the LiDFOB-coated LPSC was 3% (the mass of LiDFOB was 3% of the mass of the LPSC before coating), and the LiDFOB-coated LiNi... 0.88 Co 0.08 Mn 0.04The LiDFOB coating content in O2 is 3% (the mass of LiDFOB is the same as the mass of LiNi before coating). 0.88 Co 0.08 Mn 0.04 (3% of O2 mass); the thickness of composite cathode I is 6.75 μm, the thickness of composite cathode II is 0.75 μm, and the thickness ratio of composite cathode I to composite cathode II is 9:1.

[0121] Example 3

[0122] Using 90 parts by weight of LiNi 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P were used as materials for the composite cathode I, and 90 parts by weight of LiDFOB-coated LiNi were used. 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 A composite cathode was prepared by using 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P as materials for composite cathode II; LPSC (Li 5.5 PS 4.5 Cl 1.5 A solid electrolyte layer was prepared, and a mold battery was assembled with Li / In as the negative electrode. The battery performance was then tested.

[0123] The manufacturing process is as follows: ① The materials of composite cathode I and composite cathode II are thoroughly mixed; a certain amount of composite cathode I powder is weighed and placed in a pressing mold, and pressed into a sheet on the surface of the cathode current collector using cold pressing technology; then a certain amount of composite cathode II powder is weighed and placed in a pressing mold, and composite cathode II powder is pressed on the surface of the composite cathode I sheet to obtain a double-layer composite cathode sheet; ② LPSC solid electrolyte is prepared; ③ Matching Li / In anode to assemble the mold battery.

[0124] In Example 3, the LiDFOB coating content in the LiDFOB-coated LPSC was 5% (the mass of LiDFOB was 5% of the mass of the LPSC before coating), and the LiDFOB-coated LiNi... 0.88 Co 0.08 Mn 0.04The LiDFOB coating in O2 is 5% (the mass of LiDFOB is the same as the mass of LiNi before coating). 0.88 Co 0.08 Mn 0.04 (5% of O2 mass); the thickness of composite cathode I is 6.75 μm, the thickness of composite cathode II is 0.75 μm, and the thickness ratio of composite cathode I to composite cathode II is 9:1.

[0125] Example 4

[0126] Using 90 parts by weight of LiNi 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P were used as materials for the composite cathode I, and 90 parts by weight of LiDFOB-coated LiNi were used. 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 A composite cathode was prepared by using 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P as materials for composite cathode II; LPSC (Li 5.5 PS 4.5 Cl 1.5 A solid electrolyte layer was prepared, and a mold battery was assembled with Li / In as the negative electrode. The battery performance was then tested.

[0127] The manufacturing process is as follows: ① The materials of composite cathode I and composite cathode II are thoroughly mixed; a certain amount of composite cathode I powder is weighed and placed in a pressing mold, and pressed into a sheet on the surface of the cathode current collector using cold pressing technology; then a certain amount of composite cathode II powder is weighed and placed in a pressing mold, and composite cathode II powder is pressed on the surface of the composite cathode I sheet to obtain a double-layer composite cathode sheet; ② LPSC solid electrolyte is prepared; ③ Matching Li / In anode to assemble the mold battery.

[0128] In Example 4, the LiDFOB coating content in the LiDFOB-coated LPSC was 10% (the mass of LiDFOB was 10% of the mass of the LPSC before coating), and the LiDFOB-coated LiNi... 0.88 Co 0.08 Mn 0.04The LiDFOB coating in O2 is 10% (the mass of LiDFOB is the same as the mass of LiNi before coating). 0.88 Co 0.08 Mn 0.04 The thickness of composite cathode I is 6.75 μm, the thickness of composite cathode II is 0.75 μm, and the thickness ratio of composite cathode I to composite cathode II is 9:1.

[0129] Example 5

[0130] Using 90 parts by weight of LiNi 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P were used as materials for the composite cathode I, and 90 parts by weight of LiDFOB-coated LiNi were used. 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 A composite cathode was prepared by using 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P as materials for composite cathode II; LPSC (Li 5.5 PS 4.5 Cl 1.5 A solid electrolyte layer was prepared, and a mold battery was assembled with Li / In as the negative electrode. The battery performance was then tested.

[0131] The manufacturing process is as follows: ① The materials of composite cathode I and composite cathode II are thoroughly mixed; a certain amount of composite cathode I powder is weighed and placed in a pressing mold, and pressed into a sheet on the surface of the cathode current collector using cold pressing technology; then a certain amount of composite cathode II powder is weighed and placed in a pressing mold, and composite cathode II powder is pressed on the surface of the composite cathode I sheet to obtain a double-layer composite cathode sheet; ② LPSC solid electrolyte is prepared; ③ Matching Li / In anode to assemble the mold battery.

[0132] In Example 5, the LiDFOB coating content in the LiDFOB-coated LPSC was 0.5% (the mass of LiDFOB was 0.5% of the mass of the LPSC before coating), and the LiDFOB-coated LiNi... 0.88 Co 0.08 Mn 0.04The LiDFOB coating content in O2 is 0.5% (the mass of LiDFOB is the same as that of LiNi before coating). 0.88 Co 0.08 Mn 0.04 The thickness of composite cathode I is 6.75 μm, the thickness of composite cathode II is 0.75 μm, and the thickness ratio of composite cathode I to composite cathode II is 9:1.

[0133] Example 6

[0134] Using 90 parts by weight of LiNi 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P were used as materials for the composite cathode I, and 90 parts by weight of LiDFOB-coated LiNi were used. 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 A composite cathode was prepared by using 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P as materials for composite cathode II; LPSC (Li 5.5 PS 4.5 Cl 1.5 A solid electrolyte layer was prepared, and a mold battery was assembled with Li / In as the negative electrode. The battery performance was then tested.

[0135] The manufacturing process is as follows: ① The materials of composite cathode I and composite cathode II are thoroughly mixed; a certain amount of composite cathode I powder is weighed and placed in a pressing mold, and pressed into a sheet on the surface of the cathode current collector using cold pressing technology; then a certain amount of composite cathode II powder is weighed and placed in a pressing mold, and composite cathode II powder is pressed on the surface of the composite cathode I sheet to obtain a double-layer composite cathode sheet; ② LPSC solid electrolyte is prepared; ③ Matching Li / In anode to assemble the mold battery.

[0136] In Example 6, the coating amount of LiDFOB was the same as in Example 1, which was 1%. The thickness of composite cathode I was 5.25 μm, the thickness of composite cathode II was 2.25 μm, and the thickness ratio of composite cathode I to composite cathode II was 7:3.

[0137] Example 7

[0138] Using 90 parts by weight of LiNi 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P were used as materials for the composite cathode I, and 90 parts by weight of LiDFOB-coated LiNi was used. 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 A composite cathode was prepared by using 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P as materials for composite cathode II; LPSC (Li 5.5 PS 4.5 Cl 1.5 A solid electrolyte layer was prepared, and a mold battery was assembled with Li / In as the negative electrode. The battery performance was then tested.

[0139] The manufacturing process is as follows: ① The materials of composite cathode I and composite cathode II are thoroughly mixed; a certain amount of composite cathode I powder is weighed and placed in a pressing mold, and pressed into a sheet on the surface of the cathode current collector using cold pressing technology; then a certain amount of composite cathode II powder is weighed and placed in a pressing mold, and composite cathode II powder is pressed on the surface of the composite cathode I sheet to obtain a double-layer composite cathode sheet; ② LPSC solid electrolyte is prepared; ③ Matching Li / In anode to assemble the mold battery.

[0140] In Example 7, the coating amount of LiDFOB was the same as in Example 1, which was 1%. The thickness of composite cathode I was 3.75 μm, the thickness of composite cathode II was 3.75 μm, and the thickness ratio of composite cathode I to composite cathode II was 5:5.

[0141] Example 8

[0142] Using 90 parts by weight of LiNi 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P were used as materials for the composite cathode I, and 45 parts by weight of LiNi were used. 0.88 Co0.08 Mn 0.04 O2, 45 parts by weight of LiDFOB-coated LiNi 0.88 Co 0.08 Mn 0.04 O2, 5 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 ), 5 parts by weight of LPSC (Li 5.5 PS 4.5 Cl 1.5 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P were used as materials for composite cathode II, and 90 parts by weight of LiDFOB-coated LiNi were used. 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LPSC (Li 5.5 PS 4.5 Cl 1.5 A composite cathode was prepared by using 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P as materials for composite cathode III; LPSC (Li 5.5 PS 4.5 Cl 1.5 A solid electrolyte layer was prepared, and a mold battery was assembled with Li / In as the negative electrode. The battery performance was then tested.

[0143] The manufacturing process is as follows: ① The materials of composite cathode I, composite cathode II, and composite cathode III are thoroughly mixed evenly; a certain amount of composite cathode I powder is weighed and placed in a pressing mold, and pressed into a sheet on the surface of the cathode current collector using cold pressing technology; then a certain amount of composite cathode II powder is weighed and placed in a pressing mold, and composite cathode II powder is pressed on the surface of the composite cathode I sheet; finally, a certain amount of composite cathode III powder is weighed and placed in a pressing mold, and composite cathode III powder is pressed on the surface of the composite cathode II sheet to obtain a three-layer composite cathode sheet; ② LPSC solid electrolyte is prepared; ③ Matching Li / In negative electrode assembly mold battery.

[0144] In Example 8, the LiDFOB coating amount was the same as in Example 1, which was 1%. The thickness of composite cathode I was 5.25 μm, the thickness of composite cathode II was 1.5 μm, and the thickness of composite cathode III was 0.75 μm. The thickness ratio of composite cathode I, composite cathode II and composite cathode III was 7:2:1.

[0145] Example 9

[0146] Using 90 parts by weight of LiNi 0.88 Co0.08 Mn 0.04 O2, 10 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P were used as materials for the composite cathode I, and 60 parts by weight of LiNi were used. 0.88 Co 0.08 Mn 0.04 O2, 30 parts by weight of LiDFOB-coated LiNi 0.88 Co 0.08 Mn 0.04 O2, 6.67 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 ), 3.33 parts by weight of LPSC (Li 5.5 PS 4.5 Cl 1.5 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P were used as materials for the composite cathode II, and 30 parts by weight of LiNi were used. 0.88 Co 0.08 Mn 0.04 O2, 60 parts by weight of LiDFOB-coated LiNi 0.88 Co 0.08 Mn 0.04 O2, 6.67 parts by weight of LiDFOB-coated LPSC (Li 5.5 PS 4.5 Cl 1.5 ), 3.33 parts by weight of LPSC (Li 5.5 PS 4.5 Cl 1.5 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P were used as materials for composite cathode III, and 90 parts by weight of LiDFOB-coated LiNi were used. 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of LPSC (Li 5.5 PS 4.5 Cl 1.5 A composite cathode was prepared by using 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P as materials for the composite cathode IV; LPSC (Li 5.5 PS 4.5 Cl 1.5A solid electrolyte layer was prepared, and a mold battery was assembled with Li / In as the negative electrode. The battery performance was then tested.

[0147] The manufacturing process is as follows: ① The materials of composite cathode I, composite cathode II, composite cathode III, and composite cathode IV are thoroughly mixed evenly; a certain amount of composite cathode I powder is weighed and placed in a pressing mold, and pressed into a sheet on the surface of the cathode current collector using cold pressing technology; then a certain amount of composite cathode II powder is weighed and placed in a pressing mold, and composite cathode II powder is pressed on the surface of the composite cathode I sheet; then a certain amount of composite cathode III powder is weighed and placed in a pressing mold, and composite cathode III powder is pressed on the surface of the composite cathode II sheet; finally, a certain amount of composite cathode IV powder is weighed and placed in a pressing mold, and composite cathode IV powder is pressed on the surface of the composite cathode III sheet to obtain a four-layer composite cathode sheet; ② LPSC solid electrolyte is prepared; ③ Matching Li / In negative electrode assembly mold battery.

[0148] In Example 9, the LiDFOB coating amount was the same as in Example 1, which was 1%. The thickness of composite cathode I was 3 μm, the thickness of composite cathode II was 2.25 μm, the thickness of composite cathode III was 1.5 μm, and the thickness of composite cathode IV was 0.75 μm. The thickness ratio of composite cathode I, composite cathode II, composite cathode III and composite cathode IV was 4:3:2:1.

[0149] Comparative Example 1

[0150] Using 90 parts by weight of LiNi 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of uncoated LPSC (Li 5.5 PS 4.5 Cl 1.5 A composite cathode was prepared using 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P, and LPSC (Li 5.5 PS 4.5 Cl 1.5 A solid electrolyte layer was prepared, and a mold battery was assembled with Li / In as the negative electrode. The battery performance was then tested.

[0151] Its manufacturing process is as follows: ① 90 parts by weight of LiNi 0.88 Co 0.08 Mn 0.04 O2, 10 parts by weight of uncoated LPSC (Li 5.5 PS 4.5 Cl 1.5① Mix 0.5 parts by weight of HNBR, 0.5 parts by weight of SBR, and 0.5 parts by weight of Super P evenly, and press them onto the surface of the positive electrode current collector using cold pressing technology to obtain a composite positive electrode; ② Prepare LPSC (Li 5.5 PS 4.5 Cl 1.5 ) Solid electrolyte; ③ Matching Li / In negative electrode assembly mold battery.

[0152] Battery performance test

[0153] The sulfide electrolyte was first pre-pressed at 150 MPa using a PEEK mold. Then, indium foil and lithium copper foil (lithium copper composite strip) were sequentially assembled on one side of the electrolyte layer, and a composite positive electrode layer and carbon-coated aluminum foil were assembled on the other side. The mixture was then cold-pressed using a tablet press at 300 MPa. After tightening the bolts, a solid-state mold battery was obtained (this step was performed in an inert atmosphere). After three pre-cycles at 0.05C and 45℃ (charge / discharge voltage 2V-3.7V), charge / discharge rate tests at 0.1C-0.5C and 0.33C were conducted. The test results are recorded in Table 1.

[0154] Rct (charge transport resistance) test

[0155] The assembled battery was pre-cycled three times at 0.05C and 45℃ (charge and discharge voltage of 2V-3.7V), then fully charged at 0.1C (to 3.7V) and subjected to EIS testing. The obtained EIS data was analyzed by relaxation time distribution (DRT) to obtain Rct. The test results are recorded in Table 1.

[0156] Table 1

[0157]

[0158] As shown in Table 1, compared to Comparative Example 1, the composite cathode plates with a gradient design used in Examples 1-9 of this application can significantly improve the performance of the all-solid-state battery. Compared to Examples 6 and 7, the sublayer farthest from the cathode current collector in Example 1 is thinner, resulting in more sufficient electron transport paths inside the composite cathode and superior battery performance.

[0159] In the description of this application, the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and do not require this application to be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this application.

[0160] In the description of this specification, references to terms such as "one embodiment," "another embodiment," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment is included in at least one embodiment of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples, without contradiction. Additionally, it should be noted that in this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0161] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A composite cathode electrode sheet, characterized by, The positive electrode active material layer comprises an additive-coated positive electrode active material, an uncoated positive electrode active material, an additive-coated sulfide electrolyte, and an uncoated sulfide electrolyte. In the positive electrode active material layer, the content of the additive-coated positive electrode active material shows a trend of increase, the content of the uncoated positive electrode active material shows a trend of decrease, the content of the additive-coated sulfide electrolyte shows a trend of decrease, and the content of the uncoated sulfide electrolyte shows a trend of increase in the direction away from the positive electrode current collector. The additive comprises a lithium salt containing fluorine element and / or boron element. The mass of the additive in the additive-coated positive electrode active material is 0.1%-10% of the mass of the positive electrode active material before coating.

2. The composite cathode electrode sheet according to claim 1, characterized by The mass of the additive in the additive-coated sulfide electrolyte is 0.1%-10% of the mass of the sulfide electrolyte before coating. The positive electrode active material layer comprises a first sub-layer and a second sub-layer, and the first sub-layer is located between the positive electrode current collector and the second sub-layer.

3. The composite cathode electrode sheet according to claim 1, characterized by In the first sub-layer, the positive electrode active material is an uncoated first positive electrode active material, and the sulfide electrolyte is an additive-coated first sulfide electrolyte. In the second sub-layer, the positive electrode active material is an additive-coated second positive electrode active material, and the sulfide electrolyte is an uncoated second sulfide electrolyte. The positive electrode active material layer further comprises at least one third sub-layer, and the third sub-layer is located between the first sub-layer and the second sub-layer.

4. The composite cathode electrode sheet according to claim 3, characterized by In the third sub-layer, the positive electrode active material comprises an additive-coated third positive electrode active material and an uncoated fourth positive electrode active material, and the sulfide electrolyte comprises an additive-coated third sulfide electrolyte and an uncoated fourth sulfide electrolyte. The thickness of the sub-layer away from the positive electrode current collector is ≤ the thickness of the sub-layer close to the positive electrode current collector in any two sub-layers of the positive electrode active material layer.

5. The composite cathode electrode sheet according to claim 3 or 4, characterized in that, The additive comprises at least one of lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium difluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium bis(monofluoromalonato)borate.

6. The composite cathode electrode tab of any one of claims 1-5, wherein, The positive electrode active material comprises a ternary positive electrode material.

7. The composite cathode electrode sheet according to any one of claims 1 to 6, characterized by, The sulfide electrolyte comprises at least one of a Li-P-S system electrolyte, a argyrodite system electrolyte, and a lithium germanium phosphorus sulfur system electrolyte. The positive electrode current collector comprises an aluminum foil. The mass content of the positive electrode active material is 75%-89.5% based on the total mass of the positive electrode active material layer.

8. The composite cathode electrode tab of any one of claims 1-7, wherein, The positive electrode active material layer further comprises a binder and a conductive agent.

9. The composite cathode electrode tab of any one of claims 1-8, wherein, Optionally, the binder comprises at least one of polyvinylidene fluoride, polytetrafluoroethylene, styrene butadiene rubber, nitrile butadiene rubber, polyacrylate, polyacrylic acid, alkyl cellulose, and polyethylene oxide. Optionally, the mass content of the binder is 0.48%-2% based on the total mass of the positive electrode active material layer. ​ Optionally, the conductive agent comprises at least one of carbon black, carbon nanotube and graphene. Optionally, the mass content of the conductive agent is 0.48%-2% based on the total mass of the positive electrode active material layer.

10. A method of making a composite cathode electrode sheet, characterized by, Comprise: Providing a positive electrode current collector; Forming a positive electrode active material layer on at least one surface of the positive electrode current collector, wherein the positive electrode active material layer comprises additive-coated positive electrode active material, uncoated positive electrode active material, additive-coated sulfide electrolyte and uncoated sulfide electrolyte; in the positive electrode active material layer, the content of additive-coated positive electrode active material shows a trend of increase, the content of uncoated positive electrode active material shows a trend of decrease, the content of additive-coated sulfide electrolyte shows a trend of decrease, and the content of uncoated sulfide electrolyte shows a trend of increase in the direction away from the positive electrode current collector; the additive comprises a lithium salt containing fluorine element and / or boron element.

11. The method of claim 10, wherein, Forming the positive electrode active material layer on at least one surface of the positive electrode current collector comprises: Coating the first sulfide electrolyte with an additive to obtain additive-coated first sulfide electrolyte, uniformly mixing the additive-coated first sulfide electrolyte, uncoated first positive electrode active material, first conductive agent and first binder to obtain a first mixture, and placing the first mixture on the surface of the positive electrode current collector and pressing into a sheet to obtain a first sublayer; Coating the second positive electrode active material with an additive to obtain additive-coated second positive electrode active material, uniformly mixing the additive-coated second positive electrode active material, uncoated second sulfide electrolyte, second conductive agent and second binder to obtain a second mixture, and placing the second mixture on the side of the first sublayer away from the positive electrode current collector and pressing into a sheet to obtain a second sublayer.

12. The method of claim 11, wherein, In the step of coating the first sulfide electrolyte with an additive, the mass of the additive is 0.1%-10% of the mass of the first sulfide electrolyte before coating; And / or, in the step of coating the second positive electrode active material with an additive, the mass of the additive is 0.1%-10% of the mass of the second positive electrode active material before coating.

13. The method of claim 11, wherein, Before forming the second sublayer, forming the positive electrode active material layer on at least one surface of the positive electrode current collector further comprises a step of forming at least one third sublayer, and forming one third sublayer comprises: Coating the third positive electrode active material with an additive to obtain additive-coated third positive electrode active material; Coating the third sulfide electrolyte with an additive to obtain additive-coated third sulfide electrolyte; Uniformly mixing the additive-coated third positive electrode active material, uncoated fourth positive electrode active material, additive-coated third sulfide electrolyte, uncoated fourth sulfide electrolyte, third conductive agent and third binder to obtain a third mixture, and placing the third mixture on the side of the first sublayer away from the positive electrode current collector and pressing into a sheet to obtain a third sublayer.

14. The method according to any one of claims 11-13, characterized in that, In any two sublayers of the positive electrode active material layer, the thickness of the sublayer away from the positive electrode current collector is ≤ the thickness of the sublayer close to the positive electrode current collector.

15. The method of any one of claims 11-14, employing a method of coating the first sulfide electrolyte with an additive comprising: The additive and the first sulfide electrolyte are mixed uniformly, and the mixture is ball milled and / or mechanically fused by using a ball mill and / or a mechanical fusion machine, so that the additive is coated on the surface of the first sulfide electrolyte. And / or, the method for coating the second positive electrode active material with the additive comprises: uniformly mixing the additive and the second positive electrode active material, and ball milling and / or mechanically fusing the mixture by using a ball mill and / or a mechanical fusion machine, so that the additive is coated on the surface of the second positive electrode active material.

16. The method according to any one of claims 10-15, characterized in that, At least one of the following conditions is met: The additive comprises at least one of lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium difluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and lithium bis(monofluoromalonato)borate; The positive electrode active material comprises a ternary positive electrode material; The sulfide electrolyte comprises at least one of a Li-P-S system electrolyte, a argyrodite system electrolyte, and a lithium-germanium-phosphorus-sulfur system electrolyte; The positive electrode current collector comprises an aluminum foil; The mass content of the positive electrode active material is 75%-89.5% based on the total mass of the positive electrode active material layer.

17. An all-solid battery, characterized by comprising: The full solid-state battery comprises the positive electrode, the solid-state electrolyte layer, and the negative electrode.

18. The all-solid battery according to claim 17, characterized by The solid-state electrolyte layer comprises a sulfide solid-state electrolyte, and the sulfide solid-state electrolyte comprises at least one of a Li-P-S system electrolyte, a argyrodite system electrolyte, and a lithium-germanium-phosphorus-sulfur system electrolyte.

19. An electrical device, comprising: The full solid-state battery comprises the positive electrode, the solid-state electrolyte layer, and the negative electrode. The solid-state electrolyte layer comprises a sulfide solid-state electrolyte, and the sulfide solid-state electrolyte comprises at least one of a Li-P-S system electrolyte, a argyrodite system electrolyte, and a lithium-germanium-phosphorus-sulfur system electrolyte. The full solid-state battery comprises the positive electrode, the solid-state electrolyte layer, and the negative electrode.

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