Positive plate and preparation method thereof, all-solid-state battery, battery assembly and electric equipment

Abstract

The invention provides a positive plate and a preparation method thereof, an all-solid-state battery, a battery assembly and electric equipment. The positive plate comprises a positive active material, a first solid electrolyte and a second solid electrolyte, and the particle size ratio of the positive active material to the first solid electrolyte to the second solid electrolyte is (3-8): 1: (0.1-4). The positive plate can improve the cycle performance of the all-solid-state battery.

Description

Technical Field

[0001] The present application relates to the technical field of solid-state batteries, and in particular, to a positive electrode sheet, a preparation method thereof, a all-solid-state battery, a battery assembly, and an electrical device. Background Art

[0002] As a new generation of energy storage technology, all-solid-state batteries are regarded as an important development direction in the fields of power batteries and high-end consumer electronics. Compared with traditional lithium-ion batteries using liquid electrolytes, all-solid-state batteries use non-flammable solid electrolyte materials, fundamentally solving the risk of thermal runaway, and at the same time having a wider operating temperature range and a longer theoretical lifespan.

[0003] In related technologies, all-solid-state batteries usually adopt a laminated structure, which is composed of a positive electrode sheet, a solid electrolyte membrane, and a negative electrode sheet stacked in sequence. Among them, the positive electrode sheet adopts a composite structure design, including two functional layers, a positive electrode active material layer and a solid electrolyte layer. The positive electrode active material layer is mainly composed of lithium transition metal oxides or polyanion compounds; the solid electrolyte layer usually selects sulfide solid electrolytes or oxide solid electrolytes, and is combined with the active material layer through a dry pressing method or a solvent-assisted process to form a complete positive electrode sheet.

[0004] The inventors have found through research that the all-solid-state batteries prepared with the positive electrode sheets having the above structure have poor cycling performance. Summary of the Invention

[0005] Embodiments of the present application provide a positive electrode sheet, a preparation method thereof, an all-solid-state battery, a battery assembly, and an electrical device, so as to achieve the effect of improving the cycling performance of the all-solid-state battery.

[0006] In a first aspect, embodiments of the present application provide a positive electrode sheet, including a positive electrode active material, a first solid electrolyte, and a second solid electrolyte;

[0007] The particle size ratio of the positive electrode active material, the first solid electrolyte, and the second solid electrolyte is (3 - 8):1:(0.1 - 4).

[0008] In a possible implementation manner, the particle size of the positive electrode active material is 2.5 - 18 μm.

[0009] In a possible implementation manner, the particle size of the first solid electrolyte is 0.1 - 7 μm; the particle size of the second solid electrolyte is 0.1 - 12 μm.

[0010] In a possible implementation manner, the first solid electrolyte is a halide solid electrolyte, and the second solid electrolyte is a sulfide solid electrolyte.

[0011] In a second aspect, embodiments of the present application provide a preparation method of a positive electrode sheet, including:

[0012] Mix the first solid electrolyte with the positive electrode active material to obtain a first mixed material;

[0013] Mix the first mixed material with the second solid electrolyte to obtain a positive electrode paste;

[0014] Coat the positive electrode paste to obtain a positive electrode sheet.

[0015] In a possible implementation manner, mixing the first mixed material with the second solid electrolyte to obtain a positive electrode paste includes:

[0016] Mix the first mixed material with the second solid electrolyte and a conductive agent to obtain a second mixed material;

[0017] Mix the second mixed material with a solvent containing a binder to obtain a positive electrode paste.

[0018] In a third aspect, an embodiment of the present application provides a all-solid-state battery, including the positive electrode sheet, negative electrode sheet and a composite electrolyte membrane located between the positive electrode sheet and the negative electrode sheet in any one of the embodiments of the first aspect;

[0019] The composite electrolyte membrane includes a halide solid electrolyte layer and a sulfide solid electrolyte layer;

[0020] The halide solid electrolyte layer is located on the side close to the positive electrode sheet, and the sulfide solid electrolyte layer is located on the side close to the negative electrode sheet.

[0021] In a possible implementation manner, the negative electrode sheet includes a negative electrode active material and a sulfide solid electrolyte.

[0022] In a fourth aspect, an embodiment of the present application provides a battery assembly, including one or more than two all-solid-state batteries in any one of the embodiments of the first aspect.

[0023] In a fifth aspect, an embodiment of the present application provides an electrical device, including the all-solid-state battery in any one of the embodiments of the third aspect or the battery assembly in the embodiment of the fourth aspect.

[0024] The positive electrode sheet provided by the embodiment of the present application, its preparation method, all-solid-state battery, battery assembly, and electrical equipment. In this positive electrode sheet, by designing the particle size ratio of the positive electrode active material, the first solid electrolyte, and the second solid electrolyte to be (3-8):1:(0.1-4), the positive electrode active material forms the main framework, and the first solid electrolyte and the second solid electrolyte coat the positive electrode active material to form a three-level particle size gradient filling structure. This multi-level filling effect improves the electrode density, increases the contact area between the positive electrode active material and the solid electrolyte, constructs a continuous ion transport channel, and is beneficial to reducing the interfacial impedance. The cooperative filling of solid electrolytes with different particle sizes effectively inhibits the interfacial separation caused by the volume change of the positive electrode active material during the cycling process, thereby maintaining the integrity of the positive electrode structure. In addition, this specific particle size ratio can make each component evenly distributed, reduce the phenomenon of local current concentration, and thus effectively alleviate the occurrence of interfacial side reactions. Through this particle size cooperative regulation, the structural degradation of the positive electrode sheet during the cycling process of the all-solid-state battery is significantly inhibited, thereby improving the cycling stability of the all-solid-state battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0026] Figure 1 FIG. is a schematic structural diagram of a positive electrode sheet provided by the present application;

[0027] Figure 2 FIG. is a schematic structural diagram of an all-solid-state battery provided by the present application.

[0028] REFERENCE SIGNS:

[0029] 10. Positive electrode sheet; 11. Positive electrode active material; 12. First solid electrolyte; 13. Second solid electrolyte;

[0030] 20. Composite electrolyte membrane; 21. Halide solid electrolyte layer; 22. Sulfide solid electrolyte layer;

[0031] 30. Negative electrode sheet.

[0032] Through the above-mentioned accompanying drawings, the specific embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These accompanying drawings and text descriptions are not intended to limit the scope of the concept of the present application in any way, but to explain the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] Exemplary embodiments will be described in detail herein, and examples thereof are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0034] New energy batteries are the core components of transportation vehicles such as electric vehicles. The rapid development of the new energy electric vehicle market has driven the rapid growth of the demand for power batteries. In addition, power batteries are also applicable to electric bicycles, electric scooters, manned drones, ships, etc. At the same time, people have put forward higher requirements for the cruising range and safety of new energy electric vehicles, which requires power batteries to take into account both high energy density and high safety. All-solid-state batteries, due to their excellent kinetic performance and thermodynamic stability, can meet the requirements of high energy density and high safety at the same time, and have become the focus of research at home and abroad.

[0035] Compared with liquid lithium-ion batteries, solid-state batteries have certain application potential in the fields of power, consumption and new areas. All-solid-state batteries use solid electrodes and solid electrolytes, which can greatly improve the energy density. The solid electrolyte has a wide electrochemical window and can be adapted to positive and negative electrode materials with higher energy density. Stacking and bipolar plate structures can be adopted to further improve the energy density. At the same time, the solid electrolyte has good thermal stability, reducing the risk of thermal runaway. Due to its overall better chemical stability than the electrolyte and the all-solid-state system, it can slow down the formation of lithium dendrites and avoid the short-circuit risk caused by piercing the battery diaphragm.

[0036] At present, the positive electrode sheet of all-solid-state batteries usually adopts a composite structure design, including two functional layers: a positive electrode active material layer and a solid electrolyte layer. The positive electrode active material layer is mainly composed of lithium transition metal oxides or polyanion compounds; the solid electrolyte layer usually selects sulfide solid electrolytes or oxide solid electrolytes, and is combined with the active material layer through a dry pressing or solvent-assisted process to form a complete positive electrode sheet.

[0037] When using the above positive electrode sheet to prepare an all-solid-state battery, the positive electrode active material will undergo volume changes during the charge and discharge process of the battery, and the rigid solid electrolyte layer cannot adaptively fill the gaps generated by the volume changes like the liquid electrolyte, resulting in microcracks and contact losses at the interface after cycling. In addition, in the positive electrode sheet prepared by the dry pressing or solvent-assisted process, the poor solid-solid interface contact between the positive electrode active material and the solid electrolyte and the volume expansion problem of the electrode material will lead to a decline in the battery cycle performance, affecting the cycle life, especially under high voltage conditions, which more significantly restricts the cycle life of all-solid-state batteries.

[0038] Based on the above problems, the present application provides a positive electrode sheet, a preparation method thereof, a all-solid-state battery, a battery assembly, and an electrical device. Aiming at the key problem of solid-solid interface contact that restricts the cycle performance of all-solid-state batteries, a multi-level particle size gradient design is adopted to construct a multi-level interface structure system with self-adaptive characteristics. This particle size ratio enables the positive electrode material to spontaneously maintain close contact during the cycling process: the positive electrode active material provides stable support, and the two solid electrolytes maintain ion channels and dynamically compensate for the gaps caused by volume changes. Compared with the traditional randomly mixed electrode materials, the positive electrode sheet of the present application can significantly improve the interface contact state by regulating the particle size of the positive electrode material, effectively improving the cycle performance of all-solid-state batteries.

[0039] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail below with specific embodiments. These several specific embodiments below can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below with reference to the accompanying drawings.

[0040] Figure 1 is a schematic structural diagram of the positive electrode sheet provided in this embodiment, as Figure 1 shown, the positive electrode sheet 10 includes a positive electrode active material 11, a first solid electrolyte 12, and a second solid electrolyte 13.

[0041] It can be understood that Figure 1 it is only a schematic diagram and does not represent the actual distribution of each component in the positive electrode sheet 10.

[0042] In this embodiment, the particle size ratio of the positive electrode active material 11, the first solid electrolyte 12, and the second solid electrolyte 13 is (3-8):1:(0.1-4).

[0043] For example, the particle size ratio of the positive electrode active material 11, the first solid electrolyte 12, and the second solid electrolyte 13 is (6:1:2), (3:1:0.5), (3:1:0.2), (4:1:2), (5:1:3), (6:1:4), etc.

[0044] Optionally, the particle size of the positive electrode active material 11 is 2.5-18 μm.

[0045] For example, the particle size of the positive electrode active material 11 can be 2.5 μm, 3 μm, 5 μm, 6 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm.

[0046] Optionally, the particle size of the first solid electrolyte 12 is 0.1-7 μm.

[0047] For example, the particle size of the first solid electrolyte 12 can be 0.1 μm, 0.3 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 5 μm, 7 μm.

[0048] The particle size of the second solid electrolyte 13 is 0.1 - 12 μm.

[0049] For example, the particle size of the second solid electrolyte 13 can be 0.1 μm, 0.3 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 5 μm, 8 μm, 10 μm, 12 μm.

[0050] In this embodiment, two solid electrolytes with different particle sizes are selected and mixed with the cathode active material 11 having a larger particle size to prepare the cathode sheet 10, which can construct a stable electrode structure with multi - level filling. This hierarchical filling structure shows significant advantages during the cycling process. On the one hand, the synergistic effect of the solid electrolytes with different particle sizes ensures that there is always a sufficient contact area between the cathode active material 11 and the solid electrolyte, effectively reducing the interfacial impedance. On the other hand, the fluidity of the small - particle - size solid electrolyte can dynamically compensate for the micro - gaps generated by the volume change of the cathode active material 11 during charge and discharge, avoiding the problem of contact failure after cycling commonly found in traditional electrodes. The all - solid - state battery assembled with the cathode sheet 10 designed with different particle - size ratios has an increased cycling capacity retention rate, a reduced growth rate of the interfacial impedance, and an extended service life of the battery.

[0051] By designing the particle - size ratio of the cathode active material 11, the first solid electrolyte 12, and the second solid electrolyte 13 to be (3 - 8):1:(0.1 - 4), such a grading can make the voids of the coarse particles be exactly filled by the medium - sized particles, and the voids of the medium - sized particles be exactly filled by the fine particles, effectively reducing the porosity and reaching the maximum packing density, shortening the migration path of Li + in the battery, improving the migration rate of Li + and increasing the ionic conductivity of the cathode sheet 10. At the same time, when preparing the cathode sheet 10, not only is the conductive agent saved, the side reaction between the conductive agent and the solid electrolyte is reduced, but also the electrical performance of the all - solid - state battery is improved.

[0052] Optionally, the first solid electrolyte 12 is a halide solid electrolyte, and the second solid electrolyte 13 is a sulfide solid electrolyte.

[0053] It can be understood that the halide solid electrolyte has excellent interfacial chemical stability (especially for oxide cathode materials). Its small particle size enables it to form a coating layer on the surface of the cathode active material 11, effectively suppressing interfacial side reactions. The sulfide solid electrolyte, on the other hand, constructs a main ion transport network with a relatively high intrinsic ionic conductivity. This combination allows the small-particle-size halide solid electrolyte to preferentially fill the surface defect sites of the cathode active material 11, forming a chemically stable passivation interface. The medium-particle-size sulfide solid electrolyte maintains the overall ionic conductivity, and its larger particle size can avoid chemical incompatibility problems caused by direct contact with the cathode active material 11. In addition, during cycling, the rigid coating layer of the halide solid electrolyte can restrict the volume expansion of the cathode active material 11, while the plastic deformation ability of the sulfide solid electrolyte can absorb mechanical stress. Thus, the charge transport ability of the cathode sheet 10 in this embodiment is improved. For the all-solid-state battery prepared therefrom, the internal resistance of the battery cell is reduced, and the cycling performance is improved.

[0054] Based on the above analysis, this application also provides an all-solid-state battery. As Figure 2 shown, the all-solid-state battery in this embodiment includes the cathode sheet 10, the anode sheet 30, and the composite electrolyte membrane 20 located between the cathode sheet 10 and the anode sheet 30 in the foregoing embodiment.

[0055] Currently, the ion transport mechanism of solid electrolytes is relatively complex, and the ionic conductivity is lower than that of electrolytes, which affects the charge and discharge rate. In addition, at the interface between the solid electrolyte and the electrode material, the ion transport speed may be limited, resulting in poor fast charging performance.

[0056] Sulfide solid electrolytes are considered to be one of the solid electrolytes with the most application potential due to their high ionic conductivity, good mechanical properties, and easy synthesis. However, the electrochemical window of sulfide solid electrolytes is relatively narrow. Under high voltage conditions, sulfide solid electrolytes are easily decomposed, increasing the internal resistance of the battery cell and reducing the cycling life of the battery cell.

[0057] Considering the stability of halide solid electrolytes under high voltage, they can be directly contacted with high-voltage transition metal oxide cathodes.

[0058] Therefore, the composite electrolyte membrane 20 in the embodiments of this application includes a halide solid electrolyte layer 21 and a sulfide solid electrolyte layer 22. The halide solid electrolyte layer 21 is located on the side close to the cathode sheet 10, and the sulfide solid electrolyte layer 22 is located on the side close to the anode sheet 30.

[0059] The anode sheet 30 in the embodiments of this application includes an anode active material, a conductive agent, and a binder.

[0060] Since all-solid-state batteries use a sulfide solid electrolyte with high ionic conductivity as the negative electrode side electrolyte layer and a small-particle high-oxidation-stability halide solid electrolyte as the electrolyte in the composite positive electrode and the positive electrode side electrolyte layer, the advantages of the two solid electrolytes are combined, enabling all-solid-state batteries to have excellent electrochemical performance.

[0061] Optionally, the negative electrode sheet 30 further includes a sulfide solid electrolyte.

[0062] This application also provides a method for preparing a positive electrode sheet, including the following steps:

[0063] Step 1: Mix the first solid electrolyte 12 with the positive electrode active material 11 to obtain a first mixed material.

[0064] Step 2: Mix the first mixed material with the second solid electrolyte 13 to obtain a positive electrode slurry.

[0065] Specifically, Step 2 includes:

[0066] Step 21: Mix the first mixed material with the second solid electrolyte 13 and a conductive agent to obtain a second mixed material.

[0067] Step 22: Mix the second mixed material with a solvent containing a binder to obtain a positive electrode slurry.

[0068] Step 3: Coat and dry the positive electrode slurry to obtain the positive electrode sheet 10.

[0069] In this application, the positive electrode active material 11 is selected from at least one of lithium cobaltate, lithium iron phosphate, ternary materials, quaternary materials, lithium-rich manganese-based, and lithium manganese iron phosphate.

[0070] Taking the first solid electrolyte 12 as a halide solid electrolyte and the second electrolyte as a sulfide solid electrolyte as an example, the halide solid electrolyte is LiaMXb, where X is selected from one or more of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). a = 1 to 10, b = 1 to 10. M is a doping element selected from one or more of vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), and nickel (Ni).

[0071] The sulfide solid electrolyte is LaPcSbClcM, where a = 1 to 10, b = 1 to 10, c = 1 to 10, and M is a doping element selected from one or more of V, Cr, Mn, Fe, Co, and Ni.

[0072] The conductive agent is selected from at least one of vapor-grown carbon fiber (VGCF), superconducting carbon black (sp), carbon (C), and graphite conductive agent (KS-6).

[0073] The binder is selected from at least one of polyvinylidene fluoride - hexafluoropropylene copolymer (BI - F104), polytetrafluoroethylene (BI - PTFE), and polyvinylidene fluoride (PVDF).

[0074] The mass ratio of the positive electrode active material 11 is 60 - 98%, the total mass ratio of the first solid electrolyte 12 and the second solid electrolyte 13 is 1 - 40%, the mass ratio of the conductive agent is 1 - 10%, the solid content of the binder is 3 - 15%, and the solid content of the positive electrode slurry is 50 - 75%.

[0075] The mass ratio of the first solid electrolyte 12 to the second solid electrolyte 13 can be 1:1, or 2:8, 3:7, etc. This application does not limit this.

[0076] Optionally, for the hybrid material obtained by coating the positive electrode active material 11 with a halide solid electrolyte, the coating can be carried out not only during the preparation of the slurry, but also during the preparation of the material by coating the halide solid electrolyte on the surface of the positive electrode active material 11, so as to improve the performance of this hybrid material.

[0077] The preparation method of the negative electrode sheet 30 in this application includes the following steps:

[0078] Step 1: Mix the negative electrode active material, conductive agent, binder and solvent to prepare a negative electrode slurry.

[0079] Step 2: Coat and dry the negative electrode slurry to obtain the negative electrode sheet 30.

[0080] Among them, the mass ratio of the negative electrode active material is 95 - 99%, the mass ratio of the conductive agent is 0.8 - 5%, and the mass ratio of the binder is 0.6 - 3%. The solid content of the negative electrode slurry is 50 - 70%.

[0081] The preparation of the solid electrolyte membrane in this application includes: formulating the solid electrolyte into an electrolyte slurry; coating the electrolyte slurry on the foil and drying it.

[0082] When assembling the battery, stack the negative electrode sheet 30 and the solid electrolyte membrane, and after isostatic pressing, stack the positive electrode sheet 10 on the solid electrolyte membrane, and then press to obtain the all - solid - state battery.

[0083] When mixing the hybrid materials in this application, ball - milling mixing can be used, or equipment such as high - speed mixers and mixers can also be used. When ball - milling mixing, the rotation speed of the ball mill can be 100 - 700 rpm / min; the ball - milling time can be 30 min - 5 h; the mass ratio of the materials in the ball - milling tank to the ball - milling beads can be 1:1 - 10.

[0084] Before coating the positive electrode paste and the negative electrode paste, high-speed dispersers, degassing machines, vacuum mixers, etc. can be used for stirring to make them uniform. During coating, a knife coater, a transfer coater, and an extrusion coater can be selected as needed. For example, an extrusion coater can be selected for preparing 3C, power, and energy storage batteries.

[0085] The drying temperature of the electrode sheet is 100 - 150 °C, such as 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C.

[0086] The pressure of the isostatic pressing equipment can be 300 - 1000 MPa; the time can be 3 - 30 min.

[0087] Specific embodiments are used to further describe the above preparation method.

[0088] I. Preparation of positive electrode sheet 10:

[0089] Step 1: Put 18.55% of Li3InZrCl8 and 70% of LiCoO2 (LCO) into a ball mill for mixing, and ball mill and mix at a forward and reverse rotation speed of 420 rpm / min for 50 min, with an intermittent period of 1 min every 15 min. The ball milling medium is zirconium beads with a diameter of 1 mm to 20 mm.

[0090] The purpose of this step is to coat Li3InZrCl8 on the surface of LCO particles during ball milling.

[0091] Step 2: Add 7.95% of Li5PS4Cl2 and 3% of VGCF to the ball mill tank for mixing, and ball mill and mix at a forward and reverse rotation speed of 450 rpm / min for 60 min, with an intermittent period of 2 min every 15 min.

[0092] Step 3: Mix the ball-milled mixed material with PVDF and ethyl butyrate to prepare a positive electrode paste with a solid content of 65%.

[0093] Step 4: Use a coater to coat the positive electrode paste on the foil, and place it in an oven at 150 °C for drying to obtain the positive electrode sheet 10.

[0094] II. Preparation of negative electrode sheet 30:

[0095] Step 1: Mix 1.2% of VGCF and 98% of graphite by mass fraction with PVDF and dibromomethane to prepare a negative electrode paste with a solid content of 65%.

[0096] Step 2: Use a coater to coat the negative electrode paste on the foil, and place it in an oven at 120 °C for drying to obtain the negative electrode sheet 30.

[0097] The above percentages are all mass percentages. The differences between Examples 1-4 and Comparative Examples 1-2 and the corresponding battery cycle performance are shown in Table 1.

[0098] Table 1

[0099]

[0100] In Comparative Examples 1 and 2, the proportion of LCO was adjusted to 88.55%.

[0101] The positive electrode sheets 10 prepared by the preparation methods of Examples 1-4 and Comparative Examples 1-2 were assembled to obtain all-solid-state batteries. After the batteries were cycled 100 times, the battery cycle capacity retention rates in Table 1 were obtained.

[0102] As shown in Table 1, in Examples 1-4, the composite electrolyte and the positive electrode active material 11 were subjected to particle size compounding. Especially the particle size compounding in Example 2 could make the voids of the coarse particles be exactly filled by the medium particles, and the voids of the medium particles be exactly filled by the fine particles, and the porosity reached the minimum value. This not only made the ionic conductivity of the positive electrode sheet 10 higher, but also improved the electrical performance of the battery. Thus, it can be seen that using the positive electrode active material 11 coated with a halide solid electrolyte in the composite solid electrolyte system as the positive electrode material can effectively solve the problem of deteriorated interfacial performance of all-solid-state batteries at high voltages, improve the stability and rate performance of all-solid-state batteries, and the cut-off voltage of the all-solid-state battery can reach 4.3V - 4.8V. In addition, the preparation of the above all-solid-state battery does not require special material doping or modification, the preparation process is simple, and the preparation cost is low.

[0103] In Comparative Examples 1 and 2, the sulfide solid electrolyte was used alone and mixed with the positive electrode active material 11. Since the sulfide solid electrolyte is not resistant to high voltages, at high voltages (above 4.3V), the sulfide solid electrolyte is prone to chemical side reactions, reducing the electrochemical performance of the battery and accelerating battery failure.

[0104] This application also provides a battery assembly, including one or more than two all-solid-state batteries in the foregoing embodiments.

[0105] This application also provides an electrical device, including the all-solid-state battery in the foregoing embodiments or the battery assembly in the foregoing embodiments.

[0106] Specifically, the above electrical device can be, but is not limited to, electric vehicles, battery cars, mobile phones, tablets, laptop computers, electric toys, ships, spacecraft, etc. Among them, the electric toys can include fixed or mobile electric toys, for example, game consoles, electric vehicle toys, electric ship toys, and electric aircraft toys, etc., and the spacecraft can include airplanes, rockets, space shuttles, and spaceships, etc.

[0107] Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention, which follow the general principles of the present invention and include common general knowledge or conventional technical means in the technical field not disclosed in the present invention. It is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A positive electrode sheet, characterized in that, It includes a positive electrode active material, a first solid electrolyte, and a second solid electrolyte; The particle size ratio of the positive electrode active material, the first solid electrolyte, and the second solid electrolyte is (3 - 8):1:(0.1 - 4).

2. The positive electrode sheet according to claim 1, wherein, The particle size of the positive electrode active material is 2.5 - 18 μm.

3. The positive electrode sheet according to claim 1, characterized in that, The particle size of the first solid electrolyte is 0.1 - 7 μm; The particle size of the second solid electrolyte is 0.1 - 12 μm.

4. The positive electrode sheet according to any one of claims 1-3, characterized in that, The first solid electrolyte is a halide solid electrolyte; The second solid electrolyte is a sulfide solid electrolyte.

5. A method for preparing a positive electrode sheet, characterized in that, It includes: Mix the first solid electrolyte with the positive electrode active material to obtain a first mixed material; Mix the first mixed material with the second solid electrolyte to obtain a positive electrode paste; Coat with the positive electrode paste to obtain the positive electrode sheet.

6. The method for preparing a positive electrode sheet according to claim 5, wherein, The step of mixing the first mixed material with the second solid electrolyte to obtain a positive electrode paste includes: Mix the first mixed material with the second solid electrolyte and a conductive agent to obtain a second mixed material; Mix the second mixed material with a solvent containing a binder to obtain the positive electrode paste.

7. A all-solid-state battery, characterized in that, It includes a positive electrode sheet as described in any one of claims 1 - 4, a negative electrode sheet, and a composite electrolyte membrane located between the positive electrode sheet and the negative electrode sheet; The composite electrolyte membrane includes a halide solid electrolyte layer and a sulfide solid electrolyte layer; The halide solid electrolyte layer is located on the side close to the positive electrode sheet, and the sulfide solid electrolyte layer is located on the side close to the negative electrode sheet.

8. The all-solid-state battery according to claim 7, characterized in that, The negative electrode sheet includes a negative electrode active material and a sulfide solid electrolyte.

9. A battery assembly, characterized in that, It includes one or more than two all - solid - state batteries as described in claim 7 or 8.

10. An electrical device, characterized in that, It includes an all - solid - state battery as described in claim 7 or 8, or includes a battery assembly as described in claim 9.

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