Positive electrode membrane, positive electrode diaphragm, all-solid-state battery, electric device and application

Abstract

The invention relates to a positive electrode membrane, a positive electrode diaphragm, an all-solid-state battery, an electric device and application. The positive electrode film comprises a positive electrode active material layer, wherein the positive electrode active material layer comprises a positive electrode active material, a positive electrode solid electrolyte and a conductive agent; wherein the positive active material comprises a lithium transition metal oxide, the conductive agent comprises a non-carbon conductive material, the non-carbon conductive material comprises at least one of a Se elementary substance, a Te elementary substance and a Se / Te compound, and the chemical formula of the Se / Te compound is SexTe1-x, 0lt; xlt; 1. The positive electrode membrane can be used as a positive electrode membrane for preparing an all-solid-state battery with high discharge capacity, high rate capability and good cycle performance, and can also be used as a positive electrode membrane layer in the all-solid-state battery.

Description

Technical Field

[0001] This application relates to the technical field of all-solid-state batteries, and further relates to a positive electrode film, a positive electrode film sheet, an all-solid-state battery, an electrical device, and an application. Background Art

[0002] The statements herein only provide background information related to this application and do not necessarily constitute prior art.

[0003] An all-solid-state battery is a battery that uses solid electrodes and a solid electrolyte. The all-solid-state battery uses a solid electrolyte to replace the liquid electrolyte in a traditional battery, and the solid electrolyte can also simultaneously act as a separator between the positive electrode and the negative electrode, so a separator film can be omitted. Given the advantages of all-solid-state batteries in terms of safety, energy density, etc., all-solid-state batteries have received extensive attention in recent years. However, in all-solid-state batteries, the problems of poor interfacial contact and interfacial side reactions are one of the pain points restricting the performance, resulting in unsatisfactory discharge capacity, rate performance, and cycling performance of the battery. Summary of the Invention

[0004] In view of the above problems, this application provides a positive electrode film, a positive electrode film sheet, an all-solid-state battery, an electrical device, and an application. The positive electrode film can be used as a positive electrode film sheet for preparing an all-solid-state battery with high discharge capacity, high rate performance, and good cycling performance, or can be used as a positive electrode film layer in an all-solid-state battery.

[0005] In a first aspect, this application provides a positive electrode film, which includes a positive electrode active material layer. The positive electrode active material layer includes a positive electrode active substance, a positive electrode solid electrolyte, and a positive electrode conductive agent;

[0006] Among them, the positive electrode active substance includes a lithium transition metal oxide, the positive electrode conductive agent includes a non-carbon conductive substance, and the non-carbon conductive substance includes at least one of Se single substance, Te single substance, and Se / Te composite. The chemical formula of the Se / Te composite is Se x Te 1-x , 0 < x < 1.

[0007] The positive electrode film adopts a composite positive electrode mode, which includes a positive electrode active material, a solid electrolyte (also recorded as a positive electrode solid electrolyte) and a conductive agent (also recorded as a positive electrode conductive agent). The addition of a solid electrolyte and a conductive agent can respectively enhance the ion conductivity and the electron conductivity of the positive electrode side, promote the charge transfer efficiency between the positive electrode active material and the outside world and the full release of its capacity, wherein the positive electrode conductive agent can enhance the electron conductivity in the positive electrode film, thereby enhancing the discharge capacity and rate performance of the battery. The non-carbon conductive material introduced in the positive electrode conductive agent includes a first conductive material, and the first conductive material is at least one of a Se element, a Te element and a Se / Te complex, and is composed of one or two of selenium (Se) elements and tellurium (Te) elements. Among them, both Se and Te have high electronic conductivity, the electronic conductivity of Se is about 10mS / cm, and the electronic conductivity of Te is about 2000mS / cm, so that the non-carbon conductive material can be used as a conductive material in the positive electrode film and can provide good electronic conductivity. In addition, within the electrochemical working window of lithium transition metal oxides, selenium (Se) and tellurium (Te) have almost no electrochemical activity and can basically not participate in electrochemical reactions, thereby maintaining stable electronic conductivity. When non-carbon conductive materials are introduced as conductive agents, the peroxide ions (O2 2- ) or oxygen radicals, which can react with Se and / or Te in non-carbon conductive materials to generate SeO3 2- and / or TeO3 2- This reaction can inhibit the release of oxygen from lithium transition metal oxides, improve the structural stability of the positive electrode active material and the electrochemical performance of the battery. Therefore, by introducing non-carbon conductive materials into the positive electrode film, the prepared all-solid-state battery can have high discharge capacity, high rate performance and good cycle performance.

[0008] By utilizing the multiple synergistic effects among lithium transition metal oxides, positive electrode solid electrolytes and non-carbon conductive materials, a good and stable electrical contact network can be formed in the positive electrode membrane, reducing the interfacial impedance, promoting the charge transfer efficiency between the positive electrode active material and the outside world and the full release of its capacity, and can be used to prepare all-solid-state batteries with high discharge capacity, high rate performance and good cycle performance.

[0009] Based on any suitable embodiment of the present application, in some embodiments, at any temperature of 20°C to 100°C or in any temperature range, under the same test conditions, the electronic conductivity of the non-carbon conductive material is greater than or equal to the electronic conductivity of the Se element.

[0010] In addition to the first conductive agent, other non-carbon conductive materials with good electronic conductivity can be introduced into the positive electrode conductive agent. For example, the other non-carbon conductive materials can be non-carbon conductive materials whose electronic conductivity is better than that of Se elemental substance or is basically equivalent to that of Se elemental substance under certain temperature conditions.

[0011] Based on any suitable embodiment of the present application, in some embodiments, the weight percentage of Te element in the non-carbon conductive material is 50wt% to 100wt%, and can be optionally 60wt% to 100wt%.

[0012] Te has a high electronic conductivity (about 2000mS / cm), which can reach the same order of magnitude as traditional carbon black materials (for example, the electronic conductivity of carbon black is about 10S / cm to 100S / cm), and can provide better electronic conductivity. By setting a larger proportion of Te elements in non-carbon conductive materials, it is beneficial to reduce the amount of conductive agents and non-carbon conductive materials in the positive electrode film, which is beneficial to improve the energy density of the battery.

[0013] Based on any suitable embodiment of the present application, in some embodiments, "at least one of Se element, Te element and Se / Te complex" is recorded as the first conductive material, and the weight percentage of the first conductive material in the non-carbon conductive material is 80wt% to 100wt%.

[0014] By controlling the weight percentage of the first conductive material in the non-carbon conductive material, the first conductive material can better play the role of inhibiting the release of oxygen from lithium transition metal oxides, which is conducive to preparing an all-solid-state battery with higher discharge capacity, higher rate performance and better cycle performance.

[0015] Based on any suitable embodiment of the present application, in some embodiments, D of the non-carbon conductive material v 50 is 1 nm to 20 μm, and may be 10 nm to 5 μm, and may be further 10 nm to 1 μm; wherein D v 50 represents the particle size corresponding to when the cumulative volume distribution percentage of the multi-particle mixture reaches 50%.

[0016] By controlling the particle size of the non-carbon conductive material within the above range, it is beneficial to improve the overall electronic conductivity of the non-carbon conductive material, provide a better electrical contact network, and take into account the manufacturing cost. The relatively small particle size of the non-carbon conductive material is beneficial to improve the electrical contact between the positive electrode active materials in the electrode membrane, thereby promoting the capacity and rate performance of the all-solid-state battery. The relatively moderate particle size of the non-carbon conductive material is easier to manufacture.

[0017] Based on any suitable embodiment of the present application, in some embodiments, the weight percentage of the non-carbon conductive material in the positive electrode active material layer is 0.1 wt% to 10 wt%, and may be optionally 0.5 wt% to 5 wt%.

[0018] By controlling the weight percentage of the non-carbon conductive material in the positive electrode active material layer, it is more conducive to forming a good and stable electrical contact network and reducing the interfacial impedance, while also improving the structural stability of the positive electrode active material, and is more conducive to enabling the all-solid-state battery to achieve a higher discharge capacity, a higher rate performance, and a better cycle performance.

[0019] Based on any suitable embodiment of the present application, in some embodiments, the positive electrode solid electrolyte includes a sulfide solid electrolyte.

[0020] The sulfide solid electrolyte has very good ionic conductivity, and can better promote the charge transfer efficiency between the positive electrode active material and the outside and the full release of its capacity. Selenium (Se) and tellurium (Te) are homologous elements of sulfur (S), which enables better compatibility between the non-carbon conductive material and the sulfide solid electrolyte. Moreover, there are no oxygen-containing functional groups on the surface of the non-carbon conductive material, which can reduce the side reaction between the non-carbon conductive material and the sulfide solid electrolyte, and is conducive to reducing the interfacial impedance.

[0021] When charged to a high voltage, lithium transition metal oxides may generate oxygen, which in turn attacks the sulfide solid electrolyte, resulting in the decomposition of the sulfide solid electrolyte. When a sulfide solid electrolyte is introduced into the positive electrode of an all-solid-state battery using lithium transition metal oxides without using a non-carbon conductive material, due to the oxidative decomposition of the sulfide solid electrolyte, it is easy to cause an increase in interfacial impedance, which instead affects the discharge capacity and leads to unsatisfactory electrochemical performance of the battery. The addition of the non-carbon conductive material can inhibit the oxidative decomposition of the sulfide solid electrolyte at high voltages and give full play to the excellent ionic conduction function of the sulfide solid electrolyte. At this time, by utilizing the multiple synergistic effects among the lithium transition metal oxide, the sulfide solid electrolyte, and the non-carbon conductive material, a better and more stable electrical contact network can be formed in the positive electrode film, which is more conducive to reducing the interfacial impedance, more conducive to promoting the charge transfer efficiency between the positive electrode active material and the outside and the full release of its capacity, and is also more conducive to preparing an all-solid-state battery with a higher discharge capacity, a higher rate performance, and a good cycle performance.

[0022] In addition, in traditional lithium-ion batteries, carbon conductive materials are usually used as conductive materials. However, for a positive electrode in which the solid electrolyte contains a sulfide solid electrolyte and the positive electrode active material includes a lithium transition metal oxide, the electrochemical working window has a relatively high voltage, and the sulfide solid electrolyte is easily oxidized and decomposed at this high voltage. The compatibility between the traditional carbon conductive material and the sulfide solid electrolyte is poor, resulting in the traditional carbon conductive material being prone to accelerating the decomposition of the sulfide electrolyte, thereby increasing the interfacial impedance of the all-solid-state battery and deteriorating the battery cycling performance. There may be two reasons as follows: First, traditional carbon conductive materials usually have a large specific surface area and too high an electronic conductivity, which will greatly increase the contact area with the sulfide solid electrolyte, leading to an intensified accelerating decomposition effect on the sulfide solid electrolyte; Second, the surface of traditional carbon conductive materials generally contains oxygen-containing functional groups, and these oxygen-containing functional groups are prone to side reactions with the sulfide solid electrolyte, thereby causing a large interfacial impedance. However, if only the amount of the traditional carbon conductive material is simply reduced, the stability of the electrical contact network of the positive electrode will be affected, and further the capacity performance and rate performance of the all-solid-state battery will be affected.

[0023] In the present application, by introducing a non-carbon conductive substance into the positive electrode film, the amount of the traditional carbon conductive material in the positive electrode of the all-solid-state battery can be correspondingly replaced or reduced. Under the condition of achieving good electronic conductivity, the accelerating decomposition effect of the traditional carbon conductive substance on the sulfide solid electrolyte can be inhibited. By controlling the weight percentage of the non-carbon conductive substance in the positive electrode active material layer, under the amount of the conductive material usually required for the positive electrode film, the amount of the traditional carbon conductive material can also be correspondingly replaced or reduced. Under the condition of achieving a good and stable electrical contact network, the all-solid-state battery can have better comprehensive performance in terms of discharge capacity, rate performance and cycling performance.

[0024] In addition, for a positive electrode film including a lithium transition metal oxide and a sulfide solid electrolyte, by controlling the weight percentage of the non-carbon conductive substance in the positive electrode active material layer within a more appropriate range, it is more conducive to forming a good and stable electrical contact network and reducing the interfacial impedance, while also improving the structural stability of the positive electrode active material, and inhibiting the oxidation and decomposition of the sulfide solid electrolyte at high voltage, which is more conducive to enabling the all-solid-state battery to achieve a higher discharge capacity, a higher rate performance and a better cycling performance.

[0025] Based on any suitable implementation manner of the present application, in some implementation manners, the positive electrode conductive agent includes or does not include a carbon conductive substance, and the carbon conductive substance satisfies at least one of the following characteristics:

[0026] The weight percentage of the carbon conductive substance relative to the non-carbon conductive substance is 0 to 50 wt%, and can be optionally 0 to 33 wt%;

[0027] The weight percentage of the carbon conductive material in the positive electrode active material layer is 0 to 1 wt%, optionally 0 to 0.5 wt%, and further optionally 0;

[0028] The carbon conductive material includes one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0029] By introducing a non-carbon conductive material into the positive electrode conductive agent, the amount of the traditional carbon conductive material can be replaced or reduced. Under the condition of achieving a good and stable electrical contact network, a high discharge capacity, a high rate performance, and a good cycle performance can be imparted to the all-solid-state battery. The non-carbon conductive material provided in this application can partially or completely replace the traditional carbon conductive material, that is, less or no traditional carbon conductive material can be added to the positive electrode film.

[0030] When the non-carbon conductive material partially replaces the traditional carbon conductive material, the adverse effects of the traditional carbon conductive material can be preferably reduced by controlling the amount of the carbon conductive material within the aforementioned lower range, such as by controlling one or both of the weight percentage of the carbon conductive material in the non-carbon conductive material and the weight percentage of the carbon conductive material in the positive electrode active material layer within the aforementioned range, and a high discharge capacity, a high rate performance, and a good cycle performance can be achieved.

[0031] When the non-carbon conductive material completely replaces the traditional carbon conductive material, that is, no traditional carbon conductive material is added to the positive electrode film, at this time, under the condition of achieving a good electrical contact network, the interfacial impedance can be better reduced, the decomposition of the sulfide solid electrolyte can be more effectively inhibited, and the structural stability of the positive electrode active material can be more favorably improved, so that a higher discharge capacity, a higher rate performance, and a better cycle performance can be achieved.

[0032] The traditional carbon conductive material generally accelerates the oxidative decomposition of the sulfide solid electrolyte. Therefore, when the non-carbon conductive material is used to completely replace or partially reduce these traditional carbon conductive materials, the aforementioned functions of the non-carbon conductive material can be exerted.

[0033] Based on any suitable embodiment of this application, in some embodiments, the sulfide solid electrolyte includes at least one of a binary sulfide solid state system and a ternary sulfide solid state system;

[0034] Optionally, the binary sulfide solid state system includes one or more of Li2S-P2S5, Li2S-SiS2, Li2S-GeS2, and Li2S-B2S3;

[0035] Optionally, the ternary sulfide solid-state system includes one or more of argyrodite-type sulfide electrolytes, Li2S-MeS2-P2S5 ternary sulfide electrolytes, lithium germanium phosphorus sulfide-type sulfide electrolytes, Li2S-P2S5-MS ternary sulfide electrolytes, Li2S-P2S5-MCl ternary sulfide electrolytes, and thio-LISICON-type sulfide electrolytes; wherein, Me includes one or more elements of Si, Ge, Sn, and Al; M includes one or more elements of Ge, Al, Sn, Pb, Sb, Si, and As.

[0036] For the case where the above various sulfide solid electrolytes are included in the positive electrode of the all-solid-state battery, the oxidative decomposition of the sulfide solid electrolyte at high voltage can be inhibited by introducing a non-carbon conductive substance, thereby improving the discharge capacity, rate performance, and cycling performance of the all-solid-state battery. In addition, the first Coulombic efficiency of the all-solid-state battery can also be improved.

[0037] Furthermore, the introduction of the non-carbon conductive substance can partially or completely replace the traditional carbon conductive material, reduce the accelerating decomposition effect of the traditional carbon conductive material on the sulfide solid electrolyte, and better inhibit the decomposition of the sulfide solid electrolyte.

[0038] Based on any suitable embodiment of the present application, in some embodiments, the D v 50 of the sulfide solid electrolyte is 1 nm to 20 μm, and optionally 50 nm to 5 μm; wherein, D v 50 represents the particle size corresponding to when the cumulative volume distribution percentage of the multi-particle mixture reaches 50%.

[0039] By controlling the particle size of the sulfide solid electrolyte within the above range, it is beneficial to improve the overall ion-conducting ability of the sulfide solid electrolyte, beneficial to provide a better electrical contact network, and can take into account the manufacturing cost. A relatively small particle size of the sulfide solid electrolyte is beneficial to improving the electrical contact between the positive electrode active materials in the electrode film, thereby promoting the capacity and rate performance of the all-solid-state battery. A relatively moderate particle size of the sulfide solid electrolyte is easier to manufacture.

[0040] Based on any suitable embodiment of the present application, in some embodiments, the weight percentage of the sulfide solid electrolyte in the positive electrode active material layer is 0.1 wt% to 30 wt%, and optionally 5 wt% to 20 wt%.

[0041] The weight percentage of the sulfide solid electrolyte in the positive electrode active material layer can be controlled within the above range, which is beneficial to providing better overall ion-conducting ability.

[0042] Based on any suitable embodiment of the present application, in some embodiments, the lithium transition metal oxide includes one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium-rich manganese cathode active material, and modified forms of any one of the foregoing cathode active materials; wherein, the chemical formula of the lithium-rich manganese cathode active material is qLi2MnO3-(1-q)LiZO2, Z includes one or more elements of Ni, Co, Mn, Cr, Fe, Al, Nb, Mo, and Ru, and 0≤q≤1; the modified forms include one or more of doping modification and coating modification.

[0043] A non-carbon conductive material can be introduced into the cathode film containing the foregoing different types of lithium transition metal oxides, which can play the role of improving the discharge capacity, rate performance, and cycle performance of the all-solid-state battery.

[0044] Based on any suitable embodiment of the present application, in some embodiments, the D v 50 of the lithium transition metal oxide is 0.1 μm to 20 μm, and can be optionally 1 μm to 10 μm.

[0045] By controlling the particle size of the lithium transition metal oxide within the above range, it is beneficial to improve the discharge capacity of the cathode active material and maintain good contact between the cathode and the sulfide solid electrolyte in the composite cathode. The lithium ion transport channels inside the cathode active material with a smaller size are shorter, which is beneficial to improving the discharge capacity of the cathode active material itself; the cathode active material with a larger size can be better wrapped by the sulfide solid electrolyte, and has better interfacial contact with the sulfide solid electrolyte, which is beneficial to the cycle performance of the battery. The cathode material with a relatively moderate size can enable the battery to have both high discharge capacity and excellent cycle performance.

[0046] Based on any suitable embodiment of the present application, in some embodiments, the weight percentage of the lithium transition metal oxide in the cathode active material layer is 70 wt% to 99 wt%, and can be optionally 80 wt% to 95 wt%.

[0047] By controlling the weight percentage of the lithium transition metal oxide in the cathode active material layer within the above range, it is beneficial to balance high energy density and cycle stability.

[0048] When the cathode film also includes a sulfide solid electrolyte, by controlling the weight percentage of the lithium transition metal oxide in the cathode active material layer within the above range, it is also beneficial to achieve a balance between high energy density and reducing the oxidative decomposition effect on the sulfide solid electrolyte.

[0049] Based on any suitable embodiment of the present application, in some embodiments, the thickness of the positive electrode active material layer is 30 μm to 400 μm, and may be optionally 60 μm to 130 μm.

[0050] For the positive electrode of a all-solid-state battery, relying solely on the positive electrode active material to provide the ability to conduct electrons without adding a conductive material easily results in unsatisfactory discharge capacity and rate performance of the battery. Moreover, when the positive electrode of the all-solid-state battery is relatively thick, the above deficiencies are more obvious. At this time, for the all-solid-state battery assembled with the positive electrode film provided by the present application, the improvement of the discharge capacity and rate performance is more obvious.

[0051] In a further aspect of the present application, a positive electrode active material layer is provided, which is the positive electrode active material layer in the positive electrode film described in the first aspect of the present application.

[0052] In the second aspect of the present application, a positive electrode film is provided, which includes a positive electrode current collector and a positive electrode active material layer located on at least one side of the positive electrode current collector. The positive electrode active material layer is the positive electrode active material layer in the positive electrode film described in the first aspect of the present application.

[0053] In the third aspect of the present application, an all-solid-state battery is provided, which includes at least one of the positive electrode film described in the first aspect of the present application and the positive electrode film described in the second aspect of the present application.

[0054] In the fourth aspect of the present application, an electrical device is provided, which includes the all-solid-state battery described in the third aspect of the present application.

[0055] In the fifth aspect of the present application, the application of the positive electrode film described in the first aspect of the present application as a positive electrode film in the preparation of an all-solid-state secondary battery or as a positive electrode film layer in an all-solid-state secondary battery, or the application of the positive electrode film described in the second aspect of the present application in the preparation of an all-solid-state secondary battery is provided.

[0056] In the sixth aspect of the present application, the application of a non-carbon conductive material as a conductive agent in the positive electrode layer of an all-solid-state battery is provided. The positive electrode layer of the all-solid-state battery includes the positive electrode film described in the first aspect of the present application, and the non-carbon conductive material is the non-carbon conductive material in the positive electrode film.

[0057] The positive electrode layer of the all-solid-state battery can be prepared or provided through the aforementioned positive electrode film. In the positive electrode active material layer of the positive electrode film, the positive electrode active substance includes a lithium transition metal oxide capable of providing a high energy density, and a positive electrode solid electrolyte with a certain ionic conductivity and a non-carbon conductive substance with good electronic conductivity are also introduced; within the corresponding electrochemical window, the non-carbon conductive substance has a very stable electronic conductance ability; the non-carbon conductive substance can also absorb and solidify the oxygen that may be generated by the lithium transition metal oxide, inhibit the oxygen release of the lithium transition metal oxide, improve the structural stability of the positive electrode active substance, and thus improve the battery performance; by utilizing the multiple synergistic effects among the lithium transition metal oxide, the positive electrode solid electrolyte, and the non-carbon conductive substance, a good and stable electrical contact network can be formed in the positive electrode film, reducing the interfacial impedance, promoting the charge transfer efficiency between the positive electrode active substance and the outside and the full release of its capacity, and can be used to prepare an all-solid-state battery with a high discharge capacity, high rate performance, and good cycle performance.

[0058] When the positive electrode solid electrolyte includes a sulfide solid electrolyte, in the positive electrode active material layer of the positive electrode film, the positive electrode active substance includes a lithium transition metal oxide capable of providing a high energy density, a sulfide solid electrolyte with excellent ionic conductivity, and a non-carbon conductive substance with good electronic conductivity are also included; within the corresponding electrochemical window, the non-carbon conductive substance not only has a very stable electronic conductance ability, but also can be compatible with the sulfide solid electrolyte, with few or no side reactions with the sulfide solid electrolyte, reducing the interfacial impedance; by using the non-carbon conductive substance to absorb and solidify the oxygen that may be generated by the lithium transition metal oxide, it can not only inhibit the oxygen release of the lithium transition metal oxide, improve the structural stability of the positive electrode active substance, but also inhibit the oxidative decomposition of the sulfide solid electrolyte under high voltage, improving the battery performance; by utilizing the multiple synergistic effects among the lithium transition metal oxide, the sulfide solid electrolyte, and the non-carbon conductive substance, a good and stable electrical contact network can be formed in the positive electrode film, reducing the interfacial impedance, promoting the charge transfer efficiency between the positive electrode active substance and the outside and the full release of its capacity, and can be used to prepare an all-solid-state battery with a high discharge capacity, high rate performance, and good cycle performance.

[0059] In addition, in the positive electrode of the all-solid-state battery, traditional carbon conductive materials can be used less or not at all, which can reduce the accelerating decomposition effect of traditional carbon conductive materials on the sulfide solid electrolyte, better inhibit the decomposition of the sulfide solid electrolyte, and is more conducive to improving the discharge capacity, rate performance, and cycle performance of the all-solid-state battery.

[0060] The details of one or more embodiments or examples of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the specification, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] For a better description and illustration of the embodiments, examples or instances provided in the present application, one or more drawings may be referred to. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments, examples or instances, and the currently understood best mode of these applications. It should also be noted that the drawings are all drawn in a simplified form, only for the convenience and clarity of assisting in the description of the present application. The various dimensions of each component shown in the drawings are arbitrarily shown, which may be accurate or may not be drawn to actual scale. For example, in order to make the illustration clearer, the dimensions of some components in the drawings are appropriately exaggerated. Unless otherwise specified, the components in the drawings are not drawn to scale. The various drawings of the present application do not limit each dimension of each component. Moreover, in all the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0062] Figure 1 FIG. is a schematic diagram of the structure and internal components of a positive electrode active material layer included in a positive electrode film according to an embodiment of the present application. The positive electrode active material layer includes a lithium transition metal oxide, a positive electrode solid electrolyte, and a non-carbon conductive material.

[0063] Figure 2 FIG. is a schematic diagram of the structure and internal components of a positive electrode active material layer included in a positive electrode film according to an embodiment of the present application. The positive electrode active material layer includes a lithium transition metal oxide, a sulfide solid electrolyte, and a non-carbon conductive material.

[0064] Figure 3 FIG. is a schematic diagram of the structure of a positive electrode film according to an embodiment of the present application. The positive electrode film includes a positive electrode current collector and a positive electrode active material layer located on one side of the positive electrode current collector.

[0065] Figure 4 FIG. is a schematic diagram of the structure of a positive electrode film according to an embodiment of the present application. The positive electrode film includes a positive electrode current collector and positive electrode active material layers located on both sides of the positive electrode current collector.

[0066] Figure 5 FIG. is a schematic diagram of the structure of an all-solid-state battery cell according to an embodiment of the present application. The all-solid-state battery cell includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked in sequence.

[0067] Figure 6 is Figure 5Schematic structural diagram of an embodiment of the all-solid-state battery cell shown. The all-solid-state battery cell includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked in sequence. Among them, the positive electrode layer includes a positive electrode film of an embodiment of the present application. The positive electrode film includes a positive electrode current collector and positive electrode active material layers located on both sides of the positive electrode current collector. A positive electrode active material layer is provided between the positive electrode current collector and the solid electrolyte layer.

[0068] Figure 7 Schematic diagram of an all-solid-state battery single cell of an embodiment of the present application.

[0069] Figure 8 is Figure 7 Exploded view of an all-solid-state battery single cell of an embodiment of the present application shown.

[0070] Figure 9 Schematic diagram of a battery module of an embodiment of the present application.

[0071] Figure 10 Schematic diagram of a battery pack of an embodiment of the present application.

[0072] Figure 11 is Figure 10 Exploded view of a battery pack of an embodiment of the present application shown.

[0073] Figure 12 Schematic diagram of an electrical device using an all-solid-state battery as a power source in an embodiment of the present application.

[0074] Figure 13 Comparison of the first charge-discharge curves of Comparative Example 1 and Example 1.

[0075] Explanation of reference numerals:

[0076] 20, positive electrode film; 220, positive electrode active material layer; 221, lithium transition metal oxide; 203, positive electrode solid electrolyte; 223, sulfide solid electrolyte; 225, non-carbon conductive substance; 200, positive electrode layer; 210, positive electrode current collector; 100, solid electrolyte layer; 300, negative electrode layer; 1, battery pack; 2, upper box body; 3, lower box body; 4, battery module; 5, all-solid-state battery single cell; 51, housing; 52, all-solid-state battery cell; 53, cover plate; 6, electrical device.

[0077] It can be understood that in each drawing, the drawn dimensions of the positive electrode film 20, the positive electrode current collector 210, the positive electrode active material layer 220, the positive electrode layer 200, the solid electrolyte layer 100, and the negative electrode layer 300 do not represent the actual dimensions; Figure 1In the positive electrode active material layer 220, the shapes and sizes of the lithium transition metal oxide 221, the positive electrode solid electrolyte 203, and the non-carbon conductive material 225 do not represent or are not used to limit the shapes and sizes of the actual particles, and the illustrated numbers of the three substances do not represent or are not used to limit the actual numbers and number ratios. Figure 2 In the positive electrode active material layer 220, the shapes and sizes of the lithium transition metal oxide 221, the sulfide solid electrolyte 223, and the non-carbon conductive material 225 do not represent or are not used to limit the shapes and sizes of the actual particles, and the illustrated numbers of the three substances do not represent or are not used to limit the actual numbers and number ratios. Detailed implementation manners

[0078] Hereinafter, some implementation manners of the positive electrode film, the positive electrode film sheet, the all-solid-state battery, the electrical device, and the application of the present application have been described in detail with reference to the accompanying drawings as appropriate. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually identical structures are omitted. This is to avoid the following descriptions from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the accompanying drawings and the following descriptions are provided for those skilled in the art to fully understand the present application, and are not intended to limit the subject matter recited in the claims.

[0079] The "range" disclosed in the present application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a specific range. The range defined in this way can include or not include the end values. Any one of the end values can be independently included or not included, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, ranges of 60-110 and 80-120 are also contemplated. In addition, if the minimum range values of 1 and 2 are listed, and if the maximum range values of 3, 4, and 5 are also listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In the present application, unless otherwise specified, the numerical range "a-b" represents an abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been fully listed herein, and "0-5" is only an abbreviated representation of these numerical combinations. In addition, when it is stated that a certain parameter is an integer ≥2, it is equivalent to listing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when it is stated that a certain parameter is an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0080] In this application, unless otherwise specified, "about" means within a reasonable range above and below the given number, and the fluctuation range may vary depending on the type and value of the number. For example, fluctuations within ±10%, ±5%, ±2%, ±1%, etc. are allowed. For example, taking "about 20°C" with an approximation of ±1°C as an example, approximate values such as 19°C and 19.5°C within the approximation range indicated by "about 20°C" should also be included within the range indicated by "about 20°C".

[0081] In this application, when referring to "a plurality of", "multiple types of", "multiple items of", "several", etc., unless otherwise specified, it means greater than or equal to 2 in quantity. For example, "one or more" means one or ≥ (greater than or equal to) two. It can be understood that when referring to "any number of" items, it refers to any suitable combination of multiple items, that is, the combination of "any number of" items is carried out in a non-conflicting and implementable manner of this application.

[0082] If there is no special instruction, all embodiments and optional embodiments of this application can be combined with each other to form a new technical solution.

[0083] Referring to "embodiments" in this text means that the specific features, structures or characteristics described in combination with the embodiments can be included in at least one embodiment or implementation manner of this application. The appearance of this phrase at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments. The understanding of "implementation manners" mentioned in this text is similar.

[0084] Those skilled in the art can understand that in the methods of each embodiment or implementation manner, the written order of each step does not mean a strict execution order that constitutes any limitation to the implementation process, and the detailed execution order of each step should be determined by its function and possible internal logic. If there is no special instruction, all steps of this application can be carried out sequentially or randomly, and preferably sequentially. For example, method M includes steps (a) and (b), indicating that the method may include steps (a) and (b) carried out sequentially, or may also include steps (b) and (a) carried out sequentially. For example, method M may further include step (c), indicating that step (c) can be added to method M in any order. For example, method M can include steps (a), (b) and (c), or may also include steps (a), (c) and (b), or may also include steps (c), (a) and (b), etc.

[0085] In this application, in an open technical feature or technical solution described by words such as "containing", "comprising", "including", etc., without other explanations, additional members outside the listed members are not excluded, and it can be regarded as providing both a closed feature or solution composed of the listed members and an open feature or solution that also includes additional members outside the listed members. For example, A includes a1, a2, and a3. Without other explanations, it may also include other members or may not include additional members, and it can be regarded as providing both the feature or solution of "A is composed of a1, a2, and a3" or "A is selected from a1, a2, and a3", and also providing the feature or solution of "A not only includes a1, a2, and a3, but also includes other members".

[0086] In this application, without other explanations, A (such as B) means that B is a non-limiting example in A, and it can be understood that A is not limited to B.

[0087] In this application, "optionally", "optional", "option" mean that it is optional, that is, it refers to any one of the two parallel options of "having" or "not having". If "optional" appears multiple times in a technical solution, without special explanations and without contradictions or mutual restrictions, each "optional" is independent. Without other explanations, descriptions such as "optionally include" and "optionally contain" in this application, taking "optionally include" as an example, mean "may include or may not include".

[0088] In this application, without other explanations, the feature or solution corresponding to "and / or" includes any one of two or more related listed items, and also includes any and all combinations of the related listed items. Among them, any and all combinations include combinations of any two related listed items, any more related listed items, or all related listed items. For example, "A and / or B" means the group composed of A, B, and "the combination of A and B". Among them, "containing A and / or B" can mean "containing A, containing B, and containing the combination of A and B", and can also mean "containing A, containing B, or containing the combination of A and B", and can be appropriately understood according to the sentence where it is located.

[0089] As used herein, "its combination", "any combination thereof", "any combination mode thereof", etc. include all suitable combination modes of any two or more of the listed items.

[0090] In this article, "suitable combination mode", "suitable mode", "any suitable mode", etc., the "suitable" is subject to being able to implement the technical solution of this application.

[0091] In this text, "preferred", "better", "more preferred", "should preferably be", "relatively good", "more preferably" are only used to describe embodiments or examples with better effects. It should be understood that they do not constitute a limitation to the protection scope of this application. If the term "preferred" appears multiple times in a technical solution, without special explanation and without contradiction or mutual restraint relationship, each "preferred" is independent of each other.

[0092] In this application, terms such as "further", "even further", "especially", "for example", "such as", "example", "for illustration" are used for descriptive purposes, indicating differences in content, but should not be construed as a limitation to the protection scope of this application.

[0093] In this application, in terms such as "first aspect", "second aspect", "third aspect", "fourth aspect", "first conductive material", "second conductive material", etc., the terms "first", "second", "third", "fourth", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or quantity, nor can it be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0094] In this application, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In this application, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may represent the mutual positional relationship of horizontal height, or may only represent an attachment relationship without limiting the mutual positional relationship of horizontal height.

[0095] In this application, the term "room temperature" generally refers to 4°C to 35°C, and may refer to 20°C ± 5°C. In some embodiments or examples of this application, room temperature refers to 20°C to 30°C.

[0096] In this application, for units related to data ranges, if the unit is only attached after the right endpoint, it means that the units of the left endpoint and the right endpoint are the same. For example, both 3~5h and 3 - 5h indicate that the units of the left endpoint "3" and the right endpoint "5" are both h (hours), and they have the same meaning as 3h~5h. In addition, similar descriptions of other parameters such as temperature and size are understood in the same way.

[0097] In the embodiments or examples of the present application, the weight or mass of the relevant components mentioned not only refers to the content of each component, but also represents the proportional relationship of the weight or mass between each component. Therefore, as long as the content of the relevant components in the embodiments or examples of the present application is scaled up or down proportionally, it is within the scope described in the present application. Further, the mass involved in the embodiments or examples of the present application may be mass units well-known in the chemical industry such as micrograms (μg), milligrams (mg), grams (g), kilograms (kg), etc. Unless otherwise specified, the mass ratio is equal to the corresponding weight ratio. For example, if the mass of substance A is m1 and the weight is W1, and the mass of substance B is m2 and the weight is W2, then the mass ratio m1 / m2 is numerically equal to the corresponding weight ratio W1 / W2.

[0098] In the present application, unless otherwise specified, wt% represents the weight percentage by weight, which is numerically equal to the corresponding mass percentage by mass. In the present application, for the weight percentage, when denoted as "0", it has the same meaning as "0wt%" and can be used interchangeably.

[0099] In the present application, for the parameter units involved, unless otherwise specified, nm represents nanometer, μm represents micrometer, mS / cm represents millisiemens per centimeter, S / cm represents siemens per centimeter, V represents volt, mPa·S represents millipascal second, mg / cm 2 represents milligram per square centimeter, g / cm 2 represents gram per square centimeter, g / cm 3 represents gram per cubic centimeter, °C represents degree Celsius, mA / g represents milliampere per gram.

[0100] In the present application, "greater than or equal to", "more than or equal to" and "≥" have the same meaning and can be used interchangeably; "less than or equal to", "less than or equal to" and "≤" have the same meaning and can be used interchangeably; "greater than" can be equivalently expressed as ">", and "less than" can be equivalently expressed as "<". In the present application, unless otherwise specified, "greater than or equal to" and "≥" can be regarded as also providing two solutions of "greater than" and "equal to". In the present application, unless otherwise specified, "less than or equal to" and "≤" can be regarded as also providing two solutions of "less than" and "equal to".

[0101] In the present application, the exemplary descriptions such as "in some embodiments (or examples)" and "in one embodiment (or example)" can cover but are not limited to the following meanings: These solutions can be combined with other solutions in a suitable manner to form new technical solutions.

[0102] In all-solid-state batteries, the interface contact problem is one of the pain points restricting their performance. Poor interface contact will affect the discharge capacity of the battery and deteriorate the rate performance and cycling performance of the battery. Currently, the common practice for all-solid-state batteries is to adopt a composite cathode mode on the cathode side of the all-solid-state battery. Both cathode active materials and solid electrolytes are set in the cathode simultaneously. The solid electrolyte is used to enhance the ionic conduction ability on the cathode side, promote the charge transfer efficiency between the cathode active materials and the outside world and the full release of its capacity, and reduce the impedance. At the same time, the electronic conductivity of the cathode active material itself is used to conduct electrons to improve the cycling stability of the battery. However, without adding conductive materials, it is easy to cause insufficient electron conduction ability and poor overall electrical contact of the cathode, affecting the capacity and rate performance of all-solid-state batteries. In practical applications, relying solely on the cathode active material to provide electron conduction ability without adding conductive materials easily results in unsatisfactory discharge capacity and rate performance of the battery. When the cathode of the all-solid-state battery is relatively thick, the problem is more obvious.

[0103] Lithium transition metal oxides are one of the commonly used cathode active materials in traditional lithium-ion secondary batteries and can provide relatively good energy density. When lithium transition metal oxides are used in the cathode of all-solid-state batteries, for the cathode using lithium transition metal oxides as the cathode active material, its electrochemical working window is usually between 2.8V and 4.8V. For example, the electrochemical working windows of cathodes using lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium-rich manganese cathode active materials, etc. as cathode active materials are usually within the aforementioned range. However, at high voltages, lithium transition metal oxides are prone to releasing oxygen, which affects the stability of the cathode active material and deteriorates the cycling performance of the battery.

[0104] Sulfide solid electrolytes have excellent ionic conductivity and are a favored solid electrolyte material for all-solid-state batteries. For the cathode containing sulfide solid electrolytes, when the cathode active material includes lithium transition metal oxides, due to the relatively high voltage of the electrochemical working window, the sulfide solid electrolyte is prone to being oxidized and decomposed at this high voltage, which is likely to cause deterioration of the discharge capacity, rate performance, and cycling performance.

[0105] If a composite cathode mode is adopted on the cathode side of the all-solid-state battery, and cathode active materials, solid electrolytes, and conductive materials are set simultaneously in the cathode electrode sheet, theoretically, the solid electrolyte and the conductive material can be used to enhance the ionic conduction ability and electron conduction ability on the cathode side respectively, promote the charge transfer efficiency between the cathode active materials and the outside world and the full release of its capacity, and it is hoped that the conductive material can be used to improve the electron conduction ability in the composite cathode, thereby improving the discharge capacity and rate performance of the battery. It can be speculated that the conductive material will play a crucial role in the performance of all-solid-state batteries.

[0106] In traditional lithium-ion batteries, carbon conductive materials are usually used as conductive materials. However, for the positive electrode containing a sulfide solid electrolyte, when the positive electrode active material includes a lithium transition metal oxide, the sulfide solid electrolyte is easily oxidized and decomposed at high voltages, and the compatibility between the traditional carbon conductive material and the sulfide solid electrolyte is poor, resulting in the traditional carbon conductive material being prone to accelerating the decomposition of the sulfide electrolyte, thereby increasing the interfacial impedance of the all-solid-state battery and deteriorating the battery cycling performance. There may be two reasons as follows: First, traditional carbon conductive materials usually have a large specific surface area and too high an electronic conductivity, which will greatly increase the contact area with the sulfide solid electrolyte, leading to an accelerated decomposition effect on the sulfide solid electrolyte; Second, the surface of traditional carbon conductive materials generally contains oxygen-containing functional groups, and these oxygen-containing functional groups are prone to side reactions with the sulfide solid electrolyte, thereby causing a large interfacial impedance. However, if only the amount of traditional carbon conductive material is simply reduced, the stability of the electrical contact network of the positive electrode will be affected, and further the capacity and rate performance of the all-solid-state battery will be affected.

[0107] Based on this, the present application provides at least a positive electrode film, a positive electrode sheet, an all-solid-state battery, an electrical device, and an application. The positive electrode film can be used to prepare an all-solid-state battery with high discharge capacity, high rate performance, and good cycling performance.

[0108] In a first aspect, the present application provides a positive electrode film, which includes a positive electrode active material layer 220 (see Figure 1 ), the positive electrode active material layer 220 includes a lithium transition metal oxide 221, a positive electrode solid electrolyte 203, and a non-carbon conductive substance 225, and the non-carbon conductive substance includes at least one of Se element, Te element, and Se / Te composite, and the chemical formula of the Se / Te composite is Se x Te 1-x , where 0 < x < 1.

[0109] By utilizing the synergistic effect among the lithium transition metal oxide, the solid electrolyte, and the non-carbon conductive substance, a good and stable electrical contact network can be formed in the positive electrode film, reducing the interfacial impedance, promoting the charge transfer efficiency between the positive electrode active material and the outside and the full release of its capacity, and can be used to prepare an all-solid-state battery with high discharge capacity, high rate performance, and good cycling performance.

[0110] In this application, unless otherwise specified, the "all-solid-state battery" provided in this application refers to a battery in which the electrolyte in the battery is a solid electrolyte; generally, an all-solid-state battery includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. During the charge and discharge process of the battery, active ions are embedded and extracted back and forth between the positive electrode layer and the negative electrode layer. The solid electrolyte layer plays a role in conducting ions between the positive electrode layer and the negative electrode layer, and can also isolate the positive electrode layer from the negative electrode layer to prevent short circuit between the positive and negative electrodes. Therefore, a separator in a traditional lithium-ion battery may not be provided in an all-solid-state battery.

[0111] In this application, unless otherwise specified, the electrode layer can be a positive electrode layer or a negative electrode layer, and the "active material" in the electrode film refers to a material capable of reversibly embedding and extracting active ions. Unless otherwise specified, the "negative active material" refers to a material used in the negative electrode layer and capable of reversibly embedding and extracting active ions; the "positive active material" refers to a material used in the positive electrode layer and capable of reversibly extracting and embedding active ions. When the all-solid-state battery is charged, active ions are extracted from the positive electrode and embedded in the negative electrode through the solid electrolyte layer; when the all-solid-state battery is discharged, active ions are extracted from the negative electrode and embedded in the positive electrode. The active ions are not particularly limited and are non-restrictive. The active ions can be lithium ions, and in this case, it corresponds to a lithium-ion all-solid-state battery.

[0112] In this application, "electrode active material", "electrode active substance", "active material", and "active substance" have the same meaning and can be used interchangeably; "positive active material" and "positive electrode active material" have the same meaning and can be used interchangeably; "negative active material" and "negative electrode active material" have the same meaning and can be used interchangeably. "Positive active material" and "positive electrode active material" have the same meaning and can be used interchangeably; "negative active material" and "negative electrode active material" have the same meaning and can be used interchangeably.

[0113] In this application, unless otherwise specified, the "electrode active material layer" includes at least one of the positive electrode active material layer in the positive electrode layer and the negative electrode active material layer in the negative electrode layer. According to the specific situation, the electrode active material layer can refer to the positive electrode active material layer or the negative electrode active material layer. It can be understood that the positive electrode active material layer contains the positive electrode active substance, and the negative electrode active material layer contains the negative electrode active substance. In this application, the "electrode active material layer" can also be abbreviated as the "active material layer".

[0114] In some embodiments, a positive electrode film is provided, which includes a positive electrode active material layer 220 (for reference, see Figure 2) The positive electrode active material layer 220 includes a lithium transition metal oxide 221, a sulfide solid electrolyte 223, and a non-carbon conductive material 225. The non-carbon conductive material includes at least one of elemental Se, elemental Te, and a Se / Te composite. The chemical formula of the Se / Te composite is Se x Te 1-x , where 0 < x < 1.

[0115] In some embodiments, the present application provides a positive electrode film, which includes a positive electrode active material layer. The positive electrode active material layer includes a positive electrode active substance, a positive electrode solid electrolyte, and a positive electrode conductive agent;

[0116] Among them, the positive electrode active substance includes a lithium transition metal oxide, the positive electrode conductive agent includes a non-carbon conductive material, the non-carbon conductive material includes at least one of elemental Se, elemental Te, and a Se / Te composite. The chemical formula of the Se / Te composite is Se x Te 1-x , where 0 < x < 1.

[0117] In the present application, unless otherwise specified, the "positive electrode film" refers to a film that can be used as the positive electrode of an all-solid-state battery, including at least a positive electrode active material layer, and usually also includes a positive electrode current collector; the "positive electrode film" refers to a film that can be used as the negative electrode of an all-solid-state battery, including at least a negative electrode active material layer.

[0118] In the present application, unless otherwise specified, the "positive electrode solid electrolyte" refers to a solid electrolyte located in the positive electrode film. The positive electrode solid electrolyte can enhance the ion conduction ability of the positive electrode film, reduce the interfacial impedance, and promote the charge transfer efficiency between the positive electrode active substance and the outside and the full release of its capacity.

[0119] In the present application, unless otherwise specified, the "positive electrode conductive agent" refers to a conductive material located in the positive electrode film, which plays a role in conducting electrons in the positive electrode film, can improve the electron conduction ability in the positive electrode film, and thus improve the discharge capacity and rate performance of the battery.

[0120] In the present application, unless otherwise specified, the "lithium transition metal oxide" has the well-known meaning in the art and refers to a positive electrode active substance containing a transition metal element and a lithium element.

[0121] In the present application, unless otherwise specified, "elemental Se" and "Se in elemental form" have the same meaning and can be used interchangeably, both representing Se in elemental form. Unless otherwise specified, "elemental Te" and "Te in elemental form" have the same meaning and can be used interchangeably, both representing Te in elemental form.

[0122] In the present application, unless otherwise specified, the "Se / Te composite" refers to a composite formed by Se element and Te element, with the chemical formula Se xTe 1-x A substance where (0 < x < 1), which can also be denoted as "selenium tellurium alloy". Generally, the following method can be used to prepare a Se / Te composite with a specific atomic ratio: Weigh Se powder and Te powder according to the stoichiometric ratio, vacuum-seal them in a quartz tube, with the vacuum degree being about 10 -5 Torr, and then heat it at 900 °C to obtain a uniformly mixed melt. Quench the melt in ice water, and then a Se / Te composite (selenium tellurium alloy) can be obtained.

[0123] In this application, unless otherwise specified, the "non-carbon conductive substance" in the positive electrode film refers to a conductive substance that is different from the carbon conductive substance and has the ability to conduct electrons.

[0124] In this application, unless otherwise specified, the "carbon conductive substance" refers to a conductive substance composed of carbon elements, such as traditional carbon conductive agents, and further such as one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0125] In this application, the "non-carbon conductive substance" in the positive electrode film includes a first conductive substance; in this application, the "first conductive substance" is at least one of Se elemental substance, Te elemental substance, and Se / Te composite, and the chemical formula of the Se / Te composite is Se x Te 1-x , 0 < x < 1. Without limitation, x can be any one of the following values or a range selected from any two of the following values: 0.01, 0.02, 0.04, 0.05, 0.06, 0.08, 0.1, 0.12, 0.14, 0.15, 0.16, 0.18, 0.2, 0.22, 0.24, 0.25, 0.26, 0.28, 0.3, 0.32, 0.35, 0.36, 0.38, 0.4, 0.42, 0.44, 0.45, 0.46, 0.48, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.92, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, etc. Among them, both Se elemental substance and Te elemental substance have relatively high electronic conductivity. The electronic conductivity of Se elemental substance is about 10 mS / cm, and the electronic conductivity of Te elemental substance is about 2000 mS / cm. In addition, within the electrochemical window of 2.8 V to 4.8 V, for example, within the electrochemical working window of lithium transition metal oxides, selenium (Se) and tellurium (Te) have almost no electrochemical activity and can basically not participate in electrochemical reactions and can be basically regarded as not providing capacity. At this time, the capacity is provided by positive electrode active substances such as lithium transition metal oxides.

[0126] In the present application, the non-carbon conductive material in the positive electrode film may include other types of non-carbon conductive materials in addition to the first conductive material, such as non-carbon conductive materials having an electronic conductivity greater than or equal to that of Se under certain temperature conditions. Non-limiting examples of other types of non-carbon conductive materials include non-carbon conductive materials having an electronic conductivity greater than or equal to that of Se under the same test conditions at any temperature of 20°C to 100°C or in any temperature range.

[0127] For all-solid-state batteries with a lower electrochemical window voltage, Se and Te are used as positive electrode active materials in the positive electrode of the all-solid-state battery. At this time, Se and Te can undergo conversion reactions to store lithium; for example, the electrochemical working window of a lithium-ion all-solid-state battery (which can be recorded as a lithium-selenium battery) using selenium as the positive electrode active material is approximately between 1.0V and 3.0V.

[0128] The positive electrode film adopts a composite positive electrode mode, which includes a positive electrode active material, a solid electrolyte (also recorded as a positive electrode solid electrolyte) and a conductive agent (also recorded as a positive electrode conductive agent). The addition of a solid electrolyte and a conductive agent can respectively enhance the ion conductivity and the electron conductivity of the positive electrode side, promote the charge transfer efficiency between the positive electrode active material and the outside world and the full release of its capacity, wherein the positive electrode conductive agent can enhance the electron conductivity in the positive electrode film, thereby enhancing the discharge capacity and rate performance of the battery. The non-carbon conductive material introduced in the positive electrode conductive agent includes a first conductive material, and the first conductive material is at least one of a Se element, a Te element and a Se / Te complex, and is composed of one or two of selenium (Se) elements and tellurium (Te) elements. Among them, both Se and Te have high electronic conductivity, the electronic conductivity of Se is about 10mS / cm, and the electronic conductivity of Te is about 2000mS / cm, so that the non-carbon conductive material can be used as a conductive material in the positive electrode film and can provide good electronic conductivity. In addition, within the electrochemical working window of lithium transition metal oxides, selenium (Se) and tellurium (Te) have almost no electrochemical activity and can basically not participate in electrochemical reactions, thereby maintaining stable electronic conductivity. When non-carbon conductive materials are introduced as conductive agents, the peroxide ions (O2 2- ) or oxygen radicals, which can react with Se and / or Te in non-carbon conductive materials to generate SeO3 2- and / or TeO3 2- This reaction can inhibit the release of oxygen from lithium transition metal oxides, improve the structural stability of the positive electrode active material and the electrochemical performance of the battery. Therefore, by introducing non-carbon conductive materials into the positive electrode film, the prepared all-solid-state battery can have high discharge capacity, high rate performance and good cycle performance at the same time.

[0129] By utilizing the multiple synergistic effects among lithium transition metal oxides, solid electrolytes for the positive electrode, and non-carbon conductive substances, a good and stable electrical contact network can be formed in the positive electrode film, reducing the interfacial impedance, promoting the charge transfer efficiency between the positive electrode active material and the outside world and the full release of its capacity, and can be used to prepare all-solid-state batteries with high discharge capacity, high rate performance, and good cycle performance.

[0130] In this application, unless otherwise specified, the positive electrode active material layer sample can be obtained from the all-solid-state battery in the following way: The battery can be disassembled to obtain the active material layer sample of the electrode pole piece. Further, the following method can be used to analyze the active material layer: By using the nano-space dynamic resolution and layer-by-layer cutting technology of FIB-SEM, the three-dimensional stereoscopic structure of the sample is reconstructed, and the element distribution and proportion are obtained by combining with EDS elemental energy spectrum analysis. Finally, the composition, thickness, and other parameters of each structural layer of the active material layer are obtained through software quantitative analysis.

[0131] In this application, unless otherwise specified, the types and contents of the positive electrode active substances (including lithium transition metal oxides), conductive agents (including non-carbon conductive substances), and solid electrolytes in the positive electrode active material layer of the all-solid-state battery can be detected by the following method: The structure and composition analysis of the positive electrode active material layer can be tested and analyzed by techniques such as focused electron beam (FIB) technology, scanning electron microscope (SEM), and elemental analysis technology. For example, it can be obtained by combining cryogenic focused electron beam (FIB) serial sectioning, cross-section SEM morphology observation, energy dispersive spectroscopy (EDS) elemental energy spectrum coupling, and three-dimensional reconstruction analysis software. For example, cryogenic focused ion beam (FIB) is used to finely slice the sample layer by layer horizontally at different thickness positions (the minimum scale can reach nanoscale thin slices), and different layer samples at different thickness positions are separated. It can also be tested by scanning electron microscope (SEM). Under FIB serial sectioning, the morphology, structure, and element distribution of each layer cross-section are analyzed. Combining with three-dimensional structure reconstruction software, the three-dimensional stereoscopic structure of the sample can be reconstructed, and the mass and / or volume of different regions of the sample to be measured can be estimated. As a non-limiting example, the above-mentioned parameter test and analysis can use the FEI Scios 2HiVac device.

[0132] Based on any suitable embodiment of the present application, in some embodiments, at any temperature of 20°C to 100°C or in any temperature range, under the same test conditions, the electronic conductivity of the non-carbon conductive material is greater than or equal to the electronic conductivity of the Se element. Without limitation, the temperature of the test temperature electronic conductivity can be any of the following temperatures or an interval consisting of any two of the following temperatures: 20°C, 25°C, 26°C, 30°C, 35°C, 40°C, 45°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, etc. As a non-limiting example, the temperature of the test temperature electronic conductivity can also be 20°C to 30°C, 20°C to 40°C, 20°C to 50°C, 20°C to 60°C, 20°C to 80°C, 40°C to 50°C, 40°C to 60°C, etc.

[0133] In addition to the first conductive agent, other non-carbon conductive materials with good electronic conductivity can be introduced into the positive electrode conductive agent. For example, the other non-carbon conductive materials can be non-carbon conductive materials whose electronic conductivity is better than that of Se elemental substance or is basically equivalent to that of Se elemental substance under certain temperature conditions.

[0134] In the present application, unless otherwise specified, the electronic conductivity of the non-carbon conductive material may be tested by a conventional method for testing a powdered conductive agent, such as by a four-probe tester.

[0135] Based on any suitable embodiment of the present application, in some embodiments, the weight percentage of Te element in the non-carbon conductive material is ≥0wt%, optionally ≥50wt%, and further optionally 50wt% to 100wt%. The weight percentage of Te element in the non-carbon conductive material can also be any of the following percentages or an interval consisting of any two of the following percentages: 0wt%, 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, 70wt%, 80wt%, 90wt%, 100wt%.

[0136] Te has a high electronic conductivity (about 2000mS / cm), which can reach the same order of magnitude as traditional carbon black materials (for example, the electronic conductivity of carbon black is about 10S / cm to 100S / cm), and can provide better electronic conductivity. By setting a larger proportion of Te elements in non-carbon conductive materials, it is beneficial to reduce the amount of conductive agents and non-carbon conductive materials in the positive electrode film, which is beneficial to improve the energy density of the battery.

[0137] Based on any suitable embodiment of the present application, in some embodiments, the weight percentage of the first conductive material in the non-carbon conductive material is 80 wt% to 100 wt%, optionally 90 wt% to 100 wt%, and can also be any one of the following percentages or an interval composed of any two of the following percentages: 80 wt%, 85 wt%, 90 wt%, 95 wt%, 96 wt%, 98 wt%, 99 wt%, 99.9 wt%, 100 wt%.

[0138] Based on any suitable embodiment of the present application, in some embodiments, the non-carbon conductive material is the first conductive material, that is, it is composed of the first conductive material. At this time, the weight percentage of the first conductive material in the non-carbon conductive material is 100 wt%, and the non-carbon conductive material is at least one of Se single substance, Te single substance and Se / Te composite, and the chemical formula of the Se / Te composite is Se x Te 1-x , 0 < x < 1.

[0139] By controlling the weight percentage of the first conductive material in the non-carbon conductive material, it is beneficial to better play the role of the first conductive material in inhibiting the oxygen release of lithium transition metal oxides, and it is beneficial to prepare an all-solid-state battery with higher discharge capacity, higher rate performance and better cycle performance.

[0140] Based on any suitable embodiment of the present application, in some embodiments, the D v 50 of the non-carbon conductive material is 1 nm to 20 μm, optionally 10 nm to 5 μm, and further optionally 10 nm to 1 μm; wherein, D v 50 represents the particle size corresponding to when the cumulative volume distribution percentage of the multi-particle mixture reaches 50%. The D v 50 of the non-carbon conductive material can also be any one of the following particle sizes or an interval composed of any two of the following particle sizes: 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 80 nm, 100 nm, 0.1 μm, 150 nm, 0.15 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 1.1 μm, 1.2 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.8 μm, 2 μm, 2.2 μm, 2.4 μm, 2.5 μm, 2.6 μm, 2.8 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 4.6 μm, 4.8 μm, 5 μm, 6 μm, 8 μm, 10 μm, etc.

[0141] By controlling the particle size of the non-carbon conductive material within the above range, it is beneficial to improve the overall electron conduction ability of the non-carbon conductive material, beneficial to provide a better electrical contact network, and can take into account the manufacturing cost. The relatively small particle size of the non-carbon conductive material is beneficial to enhancing the electrical contact between the positive active materials in the electrode film, thereby promoting the capacity performance and rate performance of the all-solid-state battery. The relatively moderate particle size of the non-carbon conductive material is easier to manufacture.

[0142] In this application, unless otherwise specified, the particle size and particle size distribution of each solid particle in the positive active material layer sample of the all-solid-state battery can be analyzed in the following manner, which may include analyzing the particle size and particle size distribution of the positive active material, lithium transition metal oxide in the positive active material, non-carbon conductive material, and solid electrolyte: In this application, unless otherwise specified, a two-dimensional image with different color markings for different components can be obtained by using FIB-SEM combined with EDS testing. According to the component types, the positive active material, non-carbon conductive material, and solid electrolyte can be distinguished, and the particle size and particle size distribution of the positive active material, non-carbon conductive material, and solid electrolyte can be analyzed by using the built-in software of the EDS instrument.

[0143] In the context of this application, the volume-based cumulative particle size D v N (where N represents any value selected from 0 to 100) can be used to characterize the particle size of the material, which refers to the particle size corresponding to when the cumulative volume distribution percentage of the material reaches N%, and the volume proportion of the particles with a particle size less than or equal to D v N is N%. D v N can be obtained from the volume cumulative distribution curve of the material particle size. Unless otherwise specified, the volume cumulative distribution curve starts to accumulate from zero on the small particle size side. Taking D v 50 as an example for illustration. In this application, unless otherwise specified, D v 50 refers to the particle size corresponding to when the cumulative volume distribution percentage of the material reaches 50%, and this parameter indicates that the particle size of the particles accounting for 50% of the material volume is less than or equal to D v 50, and the particle size of the particles accounting for 50% of the material volume is greater than D v 50. Those skilled in the art can understand the meaning of D v 50, and can measure it by using the instruments and methods well-known in the art. For example, it can be conveniently measured by referring to GB / T 19077-2016 Laser Diffraction Method for Particle Size Distribution, using a laser particle size analyzer, such as the Mastersizer 2000E type laser particle size analyzer of Malvern Instruments Limited in the UK, the LS-909 laser particle size analyzer (Omec). Further, for equipment models such as the Malvern 2000 (MasterSizer 2000) laser particle size analyzer, the test can be carried out with reference to the standard process GB / T19077-2016 / ISO13320:2009.

[0144] Based on any suitable embodiment of the present application, in some embodiments, the weight percentage of the non-carbon conductive material in the positive electrode active material layer is 0.1 wt% to 10 wt%, and may be optionally 0.5 wt% to 5 wt%. The weight percentage of the non-carbon conductive material in the positive electrode active material layer may also be any one of the following weight percentages or an interval composed of any two of the following weight percentages: 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%, 1 wt%, 1.0 wt%, 1.2 wt%, 1.5 wt%, 1.6 wt%, 1.8 wt%, 2 wt%, 2.0 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, etc.

[0145] By controlling the weight percentage of the non-carbon conductive material in the positive electrode active material layer, it is more conducive to forming a good and stable electrical contact network and reducing the interface impedance, while also improving the structural stability of the positive electrode active material, and is more conducive to enabling the all-solid-state battery to achieve a higher discharge capacity, a higher rate performance, and a better cycle performance.

[0146] Based on any suitable embodiment of the present application, in some embodiments, the positive electrode solid electrolyte includes a sulfide solid electrolyte.

[0147] Non-limitingly, the weight percentage of the sulfide solid electrolyte in the positive electrode solid electrolyte may be greater than or equal to 50 wt% (i.e., ≥50 wt%), further may be greater than or equal to 60 wt%, still further may be greater than or equal to 80 wt%, still further may be greater than or equal to 90 wt%, still further may be greater than or equal to 95 wt%, and still further may be 100 wt%. The weight percentage of the sulfide solid electrolyte in the positive electrode solid electrolyte may also be any one of the following weight percentages or an interval composed of any two of the following weight percentages: 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 72 wt%, 74 wt%, 75 wt%, 76 wt%, 78 wt%, 80 wt%, 82 wt%, 84 wt%, 85 wt%, 86 wt%, 88 wt%, 90 wt%, 92 wt%, 94 wt%, 95 wt%, 96 wt%, 97 wt%, 98 wt%, 99 wt%, 100 wt%, etc.

[0148] Sulfide solid electrolytes have very good ionic conductivity. By setting sulfide solid electrolytes in the positive electrode layer, it is possible to better promote the charge transfer efficiency between the positive electrode active material and the outside world and the full release of its capacity. Further, selenium (Se) and tellurium (Te) are elements in the same group as sulfur (S), which results in good compatibility between the non-carbon conductive material and the sulfide solid electrolyte. Moreover, there are no oxygen-containing functional groups on the surface of the non-carbon conductive material, which can reduce the side reactions between the non-carbon conductive material and the sulfide solid electrolyte and is beneficial to reducing the interfacial impedance. In addition, when charged to a high voltage, lithium transition metal oxides may generate oxygen, which then attacks the sulfide solid electrolyte, leading to the decomposition of the sulfide solid electrolyte. When introducing sulfide solid electrolytes into the positive electrode of an all-solid-state battery using lithium transition metal oxides without using non-carbon conductive materials, due to the oxidative decomposition of the sulfide solid electrolyte, it is easy to cause an increase in interfacial impedance, which instead affects the discharge capacity and results in unsatisfactory electrochemical performance of the battery. The introduction of non-carbon conductive materials can inhibit the oxidative decomposition of sulfide solid electrolytes at high voltages and fully exert the excellent ionic conduction effect of sulfide solid electrolytes. At this time, by utilizing the multiple synergistic effects among lithium transition metal oxides, sulfide solid electrolytes, and non-carbon conductive materials, a better and more stable electrical contact network can be formed in the positive electrode film, which is more conducive to reducing the interfacial impedance, more conducive to promoting the charge transfer efficiency between the positive electrode active material and the outside world and the full release of its capacity, and also more conducive to preparing all-solid-state batteries with high discharge capacity, high rate performance, and good cycle performance. In the voltage range of the electrochemical working window of a lithium-ion all-solid-state battery using selenium as the positive electrode active material, the problem of oxidative decomposition of the sulfide electrolyte is not serious, and a part of the electrolyte is allowed to undergo reversible reduction, thereby providing a part of the capacity; for such lithium-selenium batteries, carbon conductive materials do not accelerate the oxidative decomposition of the sulfide electrolyte, and traditional carbon conductive materials are allowed to be used as conductive agents in the positive electrode.

[0149] In addition, in traditional lithium-ion batteries, carbon conductive materials are usually used as conductive materials. For a positive electrode where the solid electrolyte comprises a sulfide solid electrolyte and the positive electrode active material includes a lithium transition metal oxide, the electrochemical working window has a relatively high voltage. The sulfide solid electrolyte is easily oxidized and decomposed at this high voltage, and the compatibility between the traditional carbon conductive material and the sulfide solid electrolyte is poor, resulting in the traditional carbon conductive material easily accelerating the decomposition of the sulfide electrolyte, thereby increasing the interfacial impedance of the all-solid-state battery and deteriorating the battery cycle performance. There may be two reasons as follows: First, traditional carbon conductive materials usually have a large specific surface area and too high an electronic conductivity, which will greatly increase the contact area with the sulfide solid electrolyte, leading to an aggravated accelerating decomposition effect on the sulfide solid electrolyte; Second, the surface of traditional carbon conductive materials generally contains oxygen-containing functional groups, and these oxygen-containing functional groups are prone to side reactions with the sulfide solid electrolyte, thereby causing a large interfacial impedance. However, if only the amount of traditional carbon conductive material is simply reduced, the stability of the electrical contact network of the positive electrode will be affected, and further the capacity performance and rate performance of the all-solid-state battery will be affected.

[0150] In the present application, by introducing a non-carbon conductive substance into the positive electrode film, the amount of traditional carbon conductive material in the positive electrode of the all-solid-state battery can be correspondingly replaced or reduced. Under the condition of achieving good electronic conductivity, the accelerating decomposition effect of the traditional carbon conductive substance on the sulfide solid electrolyte can be inhibited. By controlling the weight percentage of the non-carbon conductive substance in the positive electrode active material layer, under the amount of conductive material usually required for the positive electrode film, the amount of traditional carbon conductive material can also be correspondingly replaced or reduced. Under the condition of achieving a good and stable electrical contact network, the all-solid-state battery can have better comprehensive performance in terms of discharge capacity, rate performance, and cycle performance.

[0151] Furthermore, for a positive electrode film including a lithium transition metal oxide and a sulfide solid electrolyte, by controlling the weight percentage of the non-carbon conductive substance in the positive electrode active material layer within a more appropriate range, it is more conducive to forming a good and stable electrical contact network and reducing the interfacial impedance, while also enhancing the structural stability of the positive electrode active material, and inhibiting the oxidation and decomposition of the sulfide solid electrolyte at high voltage, which is more conducive to enabling the all-solid-state battery to achieve a higher discharge capacity, a higher rate performance, and a better cycle performance.

[0152] In some embodiments, the positive electrode conductive agent may or may not include a carbon conductive substance.

[0153] In the present application, when the positive electrode conductive agent includes a carbon conductive agent, the corresponding carbon conductive agent can be denoted as the "second conductive substance". Without limitation, the second conductive substance may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0154] At this time, by introducing a non-carbon conductive material into the positive electrode conductive agent, the amount of the conventional carbon conductive material can be replaced or reduced under the amount of the conductive material usually required for the positive electrode film. Under the condition of achieving a good and stable electrical contact network, a high discharge capacity, a high rate performance, and a good cycle performance can be imparted to the all-solid-state battery. The non-carbon conductive material provided in this application can partially or completely replace the conventional carbon conductive material, that is, less or no conventional carbon conductive material can be added to the positive electrode film.

[0155] Based on any suitable embodiment of this application, in some embodiments, the weight percentage of the carbon conductive material relative to the non-carbon conductive material is 0 to 50 wt%, and can be optionally 0 to 33 wt%. The weight percentage of the carbon conductive material relative to the non-carbon conductive material can also be any one of the following weight percentages or an interval composed of any two of the following weight percentages: 0 wt%, 1 wt%, 2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 33 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, etc.

[0156] When the non-carbon conductive material partially replaces the conventional carbon conductive material, the adverse effects of the conventional carbon conductive material can be preferably reduced by controlling the amount of the carbon conductive material within the aforementioned lower range, for example, by controlling one or both of the weight percentage of the carbon conductive material in the non-carbon conductive material and the weight percentage of the carbon conductive material in the positive electrode active material layer within the aforementioned range, and a high discharge capacity, a high rate performance, and a good cycle performance can be achieved.

[0157] Based on any suitable embodiment of this application, in some embodiments, the weight percentage of the carbon conductive material in the positive electrode active material layer is 0 to 1 wt%, and can be optionally 0 to 0.5 wt%, and further optionally 0. The weight percentage of the carbon conductive material in the positive electrode active material layer can also be any one of the following weight percentages or an interval composed of any two of the following weight percentages: 0 wt%, 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%, 1 wt%, etc.

[0158] When the non-carbon conductive material completely replaces the conventional carbon conductive material, that is, no conventional carbon conductive material is added to the positive electrode film. At this time, under the condition of achieving a good electrical contact network, the interfacial impedance can be better reduced, the decomposition of the sulfide solid electrolyte can be more effectively inhibited, and the structural stability of the positive electrode active material can be more beneficial to improve, so that a higher discharge capacity, a higher rate performance, and a better cycle performance can be achieved.

[0159] Based on any suitable embodiment of the present application, in some embodiments, the carbon conductive material includes one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0160] Traditional carbon conductive materials generally tend to accelerate the oxidation and decomposition of sulfide solid electrolytes. Therefore, when non-carbon conductive materials are used to completely replace or partially reduce these traditional carbon conductive materials, the aforementioned effects of the non-carbon conductive materials can be exerted.

[0161] Based on any suitable embodiment of the present application, in some embodiments, the positive electrode conductive agent includes or does not include a carbon conductive material, and the carbon conductive material satisfies at least one of the following characteristics (any numerical parameter in the following characteristics can also be selected from any suitable value or range in the context):

[0162] The weight percentage of the carbon conductive material relative to the non-carbon conductive material is 0 to 50 wt%, and can be optionally 0 to 33 wt%;

[0163] The weight percentage of the carbon conductive material in the positive electrode active material layer is 0 to 1 wt%, can be optionally 0 to 0.5 wt%, and further can be optionally 0;

[0164] The carbon conductive material includes one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0165] Non-limitingly, the sulfide solid electrolyte can include at least one of a binary sulfide solid system and a ternary sulfide solid system. Non-limitingly, the binary sulfide solid system can include one or more of Li2S-P2S5, Li2S-SiS2, Li2S-GeS2, and Li2S-B2S3. Non-limitingly, the ternary sulfide solid system can include one or more of thiogermanate sulfide electrolytes, Li2S-MeS2-P2S5 ternary sulfide electrolytes, lithium germanium phosphorus sulfide electrolytes, Li2S-P2S5-MS ternary sulfide electrolytes, Li2S-P2S5-MCl ternary sulfide electrolytes, and thio-LISICON type sulfide electrolytes; wherein, Me can include one or more elements of silicon (Si), germanium (Ge), tin (Sn), and aluminum (Al), and can further be selected from one or more elements of Si, Ge, Sn, and Al; M can include one or more elements of Ge, Al, Sn, lead (Pb), antimony (Sb), Si, and arsenic (As), and can further be selected from one or more elements of Ge, Al, Sn, Pb, Sb, Si, and As.

[0166] For the case where the positive electrode of the all-solid-state battery includes the various sulfide solid electrolytes described above, the oxidation decomposition of the sulfide solid electrolyte at high voltage can be inhibited by introducing a non-carbon conductive substance, thereby improving the discharge capacity, rate performance, and cycling performance of the all-solid-state battery. In addition, the first Coulombic efficiency of the all-solid-state battery can also be increased.

[0167] Furthermore, the introduction of the non-carbon conductive substance can also partially or completely replace the traditional carbon conductive material, reducing the accelerating decomposition effect of the traditional carbon conductive material on the sulfide solid electrolyte and better inhibiting the decomposition of the sulfide solid electrolyte.

[0168] Based on any suitable implementation manner of the present application, in some implementation manners, the D v 50 of the sulfide solid electrolyte is 1 nm to 20 μm, and can be optionally 50 nm to 5 μm; wherein, D v 50 represents the particle size corresponding to when the cumulative volume distribution percentage of the multi-particle mixture reaches 50%. The D v 50 of the sulfide solid electrolyte can also be any one of the following particle sizes or an interval composed of any two of the following particle sizes: 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 80 nm, 100 nm, 0.1 μm, 150 nm, 0.15 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 1.1 μm, 1.2 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.8 μm, 2 μm, 2.2 μm, 2.4 μm, 2.5 μm, 2.6 μm, 2.8 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 4.6 μm, 4.8 μm, 5 μm, 6 μm, 8 μm, 10 μm, 12 μm, 12.5 μm, 13 μm, 14 μm, 15 μm, 16 μm, 18 μm, 20 μm, etc.

[0169] By controlling the particle size of the sulfide solid electrolyte within the above range, it is beneficial to improve the overall ion-conducting ability of the sulfide solid electrolyte, beneficial to provide a better electrical contact network, and can take into account the manufacturing cost. A relatively small particle size of the sulfide solid electrolyte is beneficial to improving the electrical contact between the positive electrode active substances in the electrode film, thereby promoting the capacity performance and rate performance of the all-solid-state battery. A relatively moderate particle size of the sulfide solid electrolyte is easier to manufacture.

[0170] Based on any suitable embodiment of the present application, in some embodiments, the weight percentage of the sulfide solid electrolyte in the positive electrode active material layer is 0.1 wt% to 30 wt%, and may be optionally 5 wt% to 20 wt%. The weight percentage of the sulfide solid electrolyte in the positive electrode active material layer may also be any one of the following weight percentages or an interval composed of any two of the following weight percentages: 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 1.6 wt%, 1.8 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 12 wt%, 14 wt%, 15 wt%, 16 wt%, 18 wt%, 20 wt%, 22 wt%, 24 wt%, 25 wt%, 26 wt%, 28 wt%, 30 wt%, etc.

[0171] The weight percentage of the sulfide solid electrolyte in the positive electrode active material layer can be controlled within the foregoing range, which is beneficial to providing better overall ionic conductivity.

[0172] Non-limitingly, the lithium transition metal oxide in the positive electrode active material may include lithium transition metal oxides known in the art that can be used as positive electrode active materials in all-solid-state batteries, but is not limited thereto. Examples of the lithium transition metal oxide may include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and their modified compounds, etc. Non-limiting examples of lithium cobalt oxide may include LiCoO2; non-limiting examples of lithium nickel oxide may include LiNiO2; non-limiting examples of lithium manganese oxide may include LiMnO2, LiMn2O4, etc.; non-limiting examples of lithium nickel cobalt manganese oxide may include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be abbreviated as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be abbreviated as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be abbreviated as NCM 622 ), LiNi 0.8Co 0.1 Mn 0.1 O2 (which can also be abbreviated as NCM 811 ) etc. Non-limiting examples of lithium nickel cobalt aluminum oxide can include LiNi 0.80 Co 0.15 Al 0.05 O2.

[0173] In some embodiments, the lithium transition metal oxide contains nickel (Ni) element. Further, the lithium transition metal oxide also contains cobalt (Co) element and Q element, and the Q element can be one or both of manganese (Mn) element and aluminum (Al) element. At this time, the atomic number ratio of nickel element to lithium element can be denoted as Q Ni . In some of these embodiments, Q Ni ≥0.3; optionally, Q Ni ≥0.5; further optionally, Q Ni ≥0.6; still further optionally, Q Ni ≥0.8; still further optionally, Q Ni ≥0.9. Q Ni Can also be any of the following values, or ≥ (greater than or equal to) any of the following values and less than 1, or be an interval composed of any two of the following values: 1 / 3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.93, etc. Q Ni Can also be selected from any of the following ranges: 0.5 ≤ Q Ni <1, 0.5 ≤ Q Ni ≤0.95, 0.5 ≤ Q Ni ≤0.94, 0.5 ≤ Q Ni ≤0.93, 0.6 ≤ Q Ni <1, 0.6 ≤ Q Ni ≤0.95, 0.6 ≤ Q Ni ≤0.94, 0.6 ≤ Q Ni ≤0.93, 0.7 ≤ Q Ni <1, 0.7 ≤ Q Ni ≤0.95, 0.7 ≤ Q Ni ≤0.94, 0.7 ≤ Q Ni ≤0.93, 0.8 ≤ Q Ni <1, 0.8 ≤ Q Ni ≤0.95, 0.8 ≤ Q Ni ≤0.94, 0.8 ≤ Q Ni ≤0.93, 0.83 ≤ Q Ni <1, 0.83 ≤ Q Ni ≤0.95, 0.83 ≤ Q Ni ≤0.94, 0.83 ≤ Q Ni≤0.93, etc.

[0174] Based on any suitable embodiment of the present application, in some embodiments, the lithium transition metal oxide includes one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium-rich manganese cathode active material, and modified forms of any one of the foregoing cathode active materials; wherein, the chemical formula of the lithium-rich manganese cathode active material can be qLi2MnO3-(1-q)LiZO2, Z can include one or more elements among nickel (Ni), cobalt (Co), manganese (Mn), chromium (Cr), iron (Fe), aluminum (Al), niobium (Nb), molybdenum (Mo), and ruthenium (Ru), 0≤q≤1; the modified form can include one or more of doping modification and coating modification. Without limitation, q can be any one of the following values or selected from the intervals formed by any two of the following values: 0, 0.01, 0.02, 0.04, 0.05, 0.06, 0.08, 0.1, 0.12, 0.14, 0.15, 0.16, 0.18, 0.2, 0.22, 0.24, 0.25, 0.26, 0.28, 0.3,

[0175] 0.32, 0.35, 0.36, 0.38, 0.4, 0.42, 0.44, 0.45, 0.46, 0.48, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.92, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1, etc.

[0176] Taking a all-solid-state battery with active ions including lithium ions as an example, it is understandable that during the charge and discharge process of the all-solid-state battery, the insertion and extraction and consumption of lithium (Li) will occur. When the battery is discharged to different states, the content of Li in the positive electrode layer (including the positive electrode film in the context) is different. In the exemplary description of the positive electrode active material in this application, unless otherwise specified, the content of Li can be the initial state of the material or the non-initial state after charge and discharge cycles. When the positive electrode active material is applied to the positive electrode layer in the all-solid-state battery system, after charge and discharge cycles, the content of Li in the positive electrode active material contained in the positive electrode layer usually changes. Among them, the content of Li can be measured by atomic molar content, but is not limited thereto. Regarding "the content of Li is the initial state of the material", the initial state of the material refers to the state before being placed in the positive electrode layer. It can be understood that new materials or new substances obtained by appropriately modifying the listed positive electrode active materials are also within the scope of the positive electrode active material. The aforementioned appropriate modification refers to the acceptable modification methods for the positive electrode active material, and non-limiting examples include coating modification. In the exemplary description of the positive electrode active material in this application, the content of oxygen (O) is usually the theoretical state value. The release of oxygen from the crystal lattice will cause changes in the atomic molar content of oxygen, and the actual content of O will fluctuate. Among them, the content of O can be measured by atomic molar content, but is not limited thereto.

[0177] In some embodiments, the positive electrode active material may include, in addition to lithium transition metal oxides, other positive electrode active materials known in the art that can be used in all-solid-state batteries. As non-limiting examples, other positive electrode active materials that can be used in all-solid-state batteries may include one or more of the following materials: lithium-containing phosphates with olivine structure and their modified compounds. However, this application is not limited to these materials, and other existing materials that can be used as positive electrode active materials for all-solid-state batteries can also be used. These positive electrode active materials can be used alone or in combination of two or more. Non-limiting examples of lithium-containing phosphates with olivine structure may include, but are not limited to, one or more of lithium iron phosphate, composite materials of lithium iron phosphate and carbon, lithium manganese phosphate, composite materials of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and composite materials of lithium manganese iron phosphate and carbon. An example of lithium iron phosphate is LiFePO4 (which can also be abbreviated as LFP for short). An example of lithium manganese phosphate is LiMnPO4.

[0178] Non-limitingly, the weight percentage of the lithium transition metal oxide in the positive electrode active material can be greater than or equal to 50 wt% (i.e., it can be ≥ 50 wt%), further can be greater than or equal to 60 wt%, still further can be greater than or equal to 80 wt%, still further can be greater than or equal to 90 wt%, still further can be greater than or equal to 95 wt%, and still further can be 100 wt%. The weight percentage of the lithium transition metal oxide in the positive electrode active material can also be any one of the following weight percentages or an interval composed of any two of the following weight percentages: 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 72 wt%, 74 wt%, 75 wt%, 76 wt%, 78 wt%, 80 wt%, 82 wt%, 84 wt%, 85 wt%, 86 wt%, 88 wt%, 90 wt%, 92 wt%, 94 wt%, 95 wt%, 96 wt%, 97 wt%, 98 wt%, 99 wt%, 100 wt%, etc.

[0179] A non-carbon conductive material can be introduced into the positive electrode film containing the foregoing different types of lithium transition metal oxides, which can play the role of improving the discharge capacity, rate performance, and cycle performance of the all-solid-state battery as described above.

[0180] In some embodiments, the D v 50 of the positive electrode active material is 0.1 μm to 20 μm, and can be optionally 1 μm to 10 μm. The D v 50 of the positive electrode active material can also be any one of the following particle sizes or an interval composed of any two of the following particle sizes: 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm,

[0181] 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm,

[0182] 13 μm, 13.5 μm, 14 μm, 14.5 μm, 15 μm, 15.5 μm, 16 μm, 16.5 μm, 17 μm, 17.5 μm, 18 μm, 18.5 μm,

[0183] 19 μm, 19.5 μm, 20 μm, etc.

[0184] Based on any suitable embodiment of the present application, in some embodiments, the D vThe D50 is from 0.1 μm to 20 μm, and can be optionally from 1 μm to 10 μm. The D50 of the lithium transition metal oxide v may also be any one of the following particle sizes or an interval composed of any two of the following particle sizes: 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.5 μm, 15 μm, 15.5 μm, 16 μm, 16.5 μm, 17 μm, 17.5 μm, 18 μm, 18.5 μm, 19 μm, 19.5 μm, 20 μm, etc.

[0185] By controlling the particle size of the lithium transition metal oxide within the above range, it is beneficial to improve the discharge capacity of the positive electrode active material and maintain good contact between the positive electrode and the sulfide solid electrolyte in the composite positive electrode. The lithium ion transport channels inside the positive electrode active material with a smaller size are shorter, which is beneficial to improving the discharge capacity of the positive electrode active material itself; the positive electrode active material with a larger size can be better wrapped by the sulfide solid electrolyte, and has better interfacial contact with the sulfide solid electrolyte, which is beneficial to the cycle performance of the battery. The positive electrode material with a relatively moderate size can enable the battery to have both high discharge capacity and excellent cycle performance.

[0186] Based on any suitable implementation manner of the present application, in some implementation manners, the weight percentage of the lithium transition metal oxide in the positive electrode active material layer is 70 wt% to 99 wt%, and can be optionally 80 wt% to 95 wt%. The weight percentage of the lithium transition metal oxide in the positive electrode active material layer may also be any one of the following weight percentages or an interval composed of any two of the following weight percentages: 70 wt%, 72 wt%, 74 wt%, 75 wt%, 76 wt%, 78 wt%, 80 wt%, 82 wt%, 84 wt%, 85 wt%, 86 wt%, 88 wt%, 90 wt%, 92 wt%, 94 wt%, 95 wt%, 96 wt%, 97 wt%, 98 wt%, 99 wt%, etc.

[0187] By controlling the weight percentage of the lithium transition metal oxide in the positive electrode active material layer within the above range, it is beneficial to balance high energy density and cycle stability.

[0188] When the positive electrode film further includes a sulfide solid electrolyte, controlling the weight percentage of the lithium transition metal oxide in the positive electrode active material layer within the above range is also conducive to achieving a balance between high energy density and reducing the oxidative decomposition of the sulfide solid electrolyte.

[0189] In this application, unless otherwise specified or there is no conflict, two or more of the features related to the technical solution provided in this application including the following features can be appropriately combined: the type of non-carbon conductive material, the weight percentage of Te element in the non-carbon conductive material, the D of the non-carbon conductive material v 50, the weight percentage of the non-carbon conductive material in the positive electrode active material layer, the weight percentage of the carbon conductive material relative to the non-carbon conductive material, the weight percentage of the carbon conductive material in the positive electrode active material layer, the type of the sulfide solid electrolyte, the D of the sulfide solid electrolyte v 50, the weight percentage of the sulfide solid electrolyte in the positive electrode active material layer, the type of the lithium transition metal oxide, the D of the positive electrode active material v 50, the D of the lithium transition metal oxide v 50, the weight percentage of the lithium transition metal oxide in the positive electrode active material layer, the weight percentage of the lithium transition metal oxide in the positive electrode active material, etc.

[0190] Non-limitingly, the positive electrode film includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is located on at least one side of the positive electrode current collector.

[0191] Based on any suitable embodiment of the present application, in some embodiments, in the positive electrode film, the thickness of the positive electrode active material layer is 30 μm to 400 μm, optionally 60 μm to 130 μm, and can also be any one of the following thicknesses or an interval composed of any two of the following thicknesses: 30 μm, 40 μm, 50 μm, 60 μm, 80 μm, 100 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 180 μm, 200 μm, etc. The thickness of the positive electrode active material layer can also be any one of the following ranges: 40 μm to 400 μm, 40 μm to 300 μm, 40 μm to 200 μm, 40 μm to 150 μm, 40 μm to 130 μm, 40 μm to 120 μm, 50 μm to 400 μm, 50 μm to 300 μm, 50 μm to 200 μm, 50 μm to 150 μm, 50 μm to 130 μm, 50 μm to 120 μm, 60 μm to 400 μm, 60 μm to 300 μm, 60 μm to 200 μm, 60 μm to 150 μm, 60 μm to 120 μm, 80 μm to 400 μm, 80 μm to 300 μm, 80 μm to 200 μm, 80 μm to 150 μm, 80 μm to 120 μm, 100 μm to 200 μm, 120 μm to 260 μm, etc.

[0192] In the present application, unless otherwise specified, the "thickness of the positive electrode active material layer" in the positive electrode film refers to the total thickness in the positive electrode film. When the positive electrode active material layers are provided on both sides of the positive electrode current collector, the thickness of the positive electrode active material layer refers to the sum of the thicknesses of both sides.

[0193] For the positive electrode of an all-solid-state battery, relying solely on the positive electrode active material to provide the ability to conduct electrons without adding a conductive material easily results in unsatisfactory discharge capacity and rate performance of the battery, and in the case where the positive electrode of the all-solid-state battery is relatively thick, the above deficiencies are more obvious. At this time, for the all-solid-state battery assembled with the positive electrode film provided by the present application, the improvement of the discharge capacity and rate performance is more obvious.

[0194] In some embodiments, the positive electrode active material layer optionally includes a binder. As a non-limiting example, the binder can include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin. Generally, the weight percentage of the binder in the positive electrode active material layer can be 0 to 10 wt%, further can be 0 to 8 wt%, still further can be 0.1 wt% to 5 wt%, and still further can be 1 wt% to 5 wt%, based on the total weight of the positive electrode active material layer.

[0195] The following are some other descriptions about the positive electrode film.

[0196] Non - restrictively, the positive electrode film includes a positive electrode current collector and a positive electrode active material layer disposed on at least one side of the positive electrode current collector. The definition of the positive electrode active material layer can be referred to the foregoing text.

[0197] In some embodiments, the positive electrode film includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector. The definition of the positive electrode active material layer can be referred to the foregoing text.

[0198] In some embodiments, refer to Figure 3 , the positive electrode film 20 includes a positive electrode current collector 210 and a positive electrode active material layer 220 located on one side of the positive electrode current collector 210.

[0199] In some embodiments, refer to Figure 4 , the positive electrode film 20 includes a positive electrode current collector 210 and positive electrode active material layers 220 located on both sides of the positive electrode current collector 210.

[0200] Non - restrictively, the weight percentage of the positive electrode active substance in the positive electrode active material layer can be ≥80 wt%, and further can be ≥90 wt%.

[0201] As a non - restrictive example, the positive electrode current collector has two surfaces facing away from each other in its own thickness direction, and the positive electrode active material layer is disposed on either one or both of the two opposite surfaces of the positive electrode current collector.

[0202] In some embodiments, the positive electrode film can be in the form of a positive electrode film layer or a positive electrode film sheet.

[0203] The aforementioned positive electrode film can be an independent positive electrode film sheet, and thus can be used to assemble a all - solid - state battery; the aforementioned positive electrode film can also be a positive electrode film layer existing in a composite structure, and the constituent materials of the positive electrode film layer can be pressed into a film on the surface of the solid electrolyte layer.

[0204] In some embodiments, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, aluminum foil can be used. In the positive electrode current collector, the composite current collector can include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. In the positive electrode current collector, the composite current collector can be obtained by forming a metal material on a polymer material substrate. In the positive electrode current collector, non - restrictive examples of the metal material can include at least one of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc. In the positive electrode current collector, non - restrictive examples of the polymer material substrate can include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0205] The positive electrode film can be prepared by a dry process or a wet process. For example, it can be formed into a film by dry pressing. Another example is that it can be formed into a film by wet coating.

[0206] In some embodiments, the positive electrode film can be prepared in the following manner: dry-mix the components for preparing the positive electrode film described above, such as the positive electrode active material, the positive electrode solid electrolyte, the positive electrode conductive agent, the binder, and any other components, and then heat and press the mixed material to knead it into a mass, perform hot roll pressing to form a self-supporting positive electrode sheet, and thermally roll-compound the self-supporting positive electrode sheet with the positive electrode current collector. The self-supporting positive electrode sheet can be compounded on at least one side (single-sided or double-sided) of the positive electrode current collector to obtain the positive electrode film. Without limitation, a double planetary mixer can be used for dry mixing. Without limitation, a kneader can be used for heating and pressing kneading. Without limitation, the temperature for hot roll pressing can be 75°C to 85°C, further such as 78°C, 80°C, 82°C, etc. The method of assembling an all-solid-state battery using the positive electrode film is suitable for industrial mass production.

[0207] In some embodiments, the positive electrode film can be prepared in the following manner: disperse the components for preparing the positive electrode film described above, such as the positive electrode active material, the positive electrode conductive agent, the binder, and any other components, in an organic solvent to form a positive electrode slurry. Further, coat the positive electrode slurry on at least one surface of the positive electrode current collector, and after processes such as drying and cold pressing, the positive electrode film can be obtained. Cold pressing can be performed using a cold rolling mill. The types of organic solvents in the positive electrode slurry can include one or two of p-xylene, mesitylene, butyl butyrate, heptane, etc., and further can be p-xylene. The surface of the positive electrode current collector coated with the positive electrode slurry can be a single surface of the positive electrode current collector or two surfaces of the positive electrode current collector. The surface of the positive electrode current collector coated with the positive electrode slurry can be a single surface of the positive electrode current collector or two surfaces of the positive electrode current collector. The solid content of the positive electrode slurry can be 40 wt% to 80 wt%. The viscosity of the positive electrode slurry at room temperature can be adjusted to 5000 mPa·s to 25000 mPa·s. When coating the positive electrode slurry, the coating unit surface density in terms of dry weight (deducting the solvent) can be 15 g / cm 3 ~35 mg / cm 2 。The compaction density of the positive electrode film can be 3.0 g / cm 3 ~3.6 g / cm 3 ,optionally 3.3 g / cm 3 ~3.5 g / cm 3 。

[0208] The "compacted density" used in this application has the meaning well-known in the art and is one of the reference indicators of the energy density of materials. In this application, unless otherwise specified, the compacted density of the electrode layer refers to the ratio of the mass of the electrode active material layer to its volume. The compacted density of the positive electrode layer, positive electrode film or positive electrode membrane refers to the ratio of the mass of the positive electrode active material layer to its volume, and the compacted density of the negative electrode layer, negative electrode plate or negative electrode membrane refers to the ratio of the mass of the negative electrode active material layer to its volume.

[0209] In yet another aspect of this application, a positive electrode active material layer is provided, which is the positive electrode active material layer in the positive electrode membrane described in the first aspect of this application.

[0210] In the second aspect of this application, a positive electrode membrane is provided, which includes a positive electrode current collector and a positive electrode active material layer located on at least one side of the positive electrode current collector. The positive electrode active material layer is the positive electrode active material layer in the positive electrode membrane described in the first aspect of this application.

[0211] In the third aspect of this application, a all-solid-state battery is provided, which includes at least one of the positive electrode membrane described in the first aspect of this application and the positive electrode membrane described in the second aspect of this application.

[0212] In the fourth aspect of this application, an electrical device is provided, which includes the all-solid-state battery described in the third aspect of this application.

[0213] In the fifth aspect of this application, the application of the positive electrode membrane described in the first aspect of this application as a positive electrode membrane in the preparation of an all-solid-state secondary battery or as a positive electrode membrane layer in an all-solid-state secondary battery, or the application of the positive electrode membrane described in the second aspect of this application in the preparation of an all-solid-state secondary battery is provided.

[0214] In the sixth aspect of this application, the application of a non-carbon conductive material as a conductive agent in the positive electrode layer of an all-solid-state battery is provided. The positive electrode layer of the all-solid-state battery is the positive electrode membrane described in the first aspect of this application, and the non-carbon conductive material is the non-carbon conductive material in the positive electrode membrane.

[0215] In some embodiments, the positive electrode membrane is located in the positive electrode layer of an all-solid-state secondary battery. The working voltage of the all-solid-state secondary battery can be greater than 2.5V, further can be greater than or equal to 3.0V, still further can be 3.0V - 4.8V, and still further can be 3.0V - 4.3V, but not limited thereto.

[0216] The positive electrode layer of the all-solid-state battery can be prepared or provided through the aforementioned positive electrode film. In the positive electrode active material layer of the positive electrode film, the positive electrode active substance includes a lithium transition metal oxide capable of providing a high energy density, and a positive electrode solid electrolyte with a certain ionic conductivity and a non-carbon conductive substance with good electronic conductivity are also introduced. Within the corresponding electrochemical window, the non-carbon conductive substance has a very stable electronic conductivity ability. The non-carbon conductive substance can also absorb and solidify the oxygen that may be generated by the lithium transition metal oxide, inhibit the oxygen release of the lithium transition metal oxide, improve the structural stability of the positive electrode active substance, and thus improve the battery performance. By utilizing the multiple synergistic effects among the lithium transition metal oxide, the positive electrode solid electrolyte, and the non-carbon conductive substance, a good and stable electrical contact network can be formed in the positive electrode film, reducing the interfacial impedance, promoting the charge transfer efficiency between the positive electrode active substance and the outside and the full release of its capacity, and can be used to prepare an all-solid-state battery with a high discharge capacity, high rate performance, and good cycle performance.

[0217] When the positive electrode solid electrolyte includes a sulfide solid electrolyte, in the positive electrode active material layer of the positive electrode film, the positive electrode active substance includes a lithium transition metal oxide capable of providing a high energy density, a sulfide solid electrolyte with excellent ionic conductivity, and a non-carbon conductive substance with good electronic conductivity. Within the corresponding electrochemical window, the non-carbon conductive substance not only has a very stable electronic conductivity ability but also can be compatible with the sulfide solid electrolyte, with few or no side reactions with the sulfide solid electrolyte, reducing the interfacial impedance. By using the non-carbon conductive substance to absorb and solidify the oxygen that may be generated by the lithium transition metal oxide, it can not only inhibit the oxygen release of the lithium transition metal oxide, improve the structural stability of the positive electrode active substance, but also inhibit the oxidative decomposition of the sulfide solid electrolyte at high voltages, improving the battery performance. By utilizing the multiple synergistic effects among the lithium transition metal oxide, the sulfide solid electrolyte, and the non-carbon conductive substance, a good and stable electrical contact network can be formed in the positive electrode film, reducing the interfacial impedance, promoting the charge transfer efficiency between the positive electrode active substance and the outside and the full release of its capacity, and can be used to prepare an all-solid-state battery with a high discharge capacity, high rate performance, and good cycle performance.

[0218] In addition, in the positive electrode of the all-solid-state battery, traditional carbon conductive materials can be used less or not at all, which can reduce the accelerating decomposition effect of traditional carbon conductive materials on the sulfide solid electrolyte, better inhibit the decomposition of the sulfide solid electrolyte, and is more conducive to improving the discharge capacity, rate performance, and cycle performance of the all-solid-state battery.

[0219] Unless otherwise specified, the all-solid-state battery provided in this application is an all-solid-state secondary battery.

[0220] In the present application, the all-solid-state battery includes an all-solid-state battery cell, and the all-solid-state battery cell includes the positive electrode film described in the first aspect of the present application.

[0221] In some embodiments, Te powder is used as the positive electrode conductive agent. Since Te powder has higher electronic conductivity, the all-solid-state battery prepared using Te powder as the positive electrode conductive agent has better electrochemical performance compared with some embodiments using only Se powder as the positive electrode conductive agent.

[0222] In some embodiments, the non-carbon conductive material includes both Se and Te elements, and the discharge capacity, rate performance and cycle performance of the all-solid-state battery are very excellent. x Te 1-x Se and Te in the complex are combined at the atomic scale, and the synergistic effect is generally better than that of a simple mixture of Se and Te.

[0223] In some embodiments, the positive electrode solid electrolyte includes a sulfide solid electrolyte, and the non-carbon conductive material includes both Se and Te elements, and the discharge capacity, rate performance and cycle performance of the all-solid-state battery are improved. This is because there is a synergistic effect between Se and Te elements, and Se is more likely to combine with peroxide ions to form SeO3 2- , which is more conducive to inhibiting the decomposition of sulfide solid electrolytes; when the Te content is high, the electronic conductivity of the non-carbon conductive material is higher and can provide more sufficient electronic conduction channels. x Te 1-x When Se and Te are added as a composite or mixed, all-solid-state batteries can easily obtain better electrochemical performance.

[0224] In some embodiments, the particle size of the non-carbon conductive material is relatively small, and the discharge capacity and cycle stability of the all-solid-state battery are improved. This is because when the particle size of the non-carbon conductive material becomes smaller, the electronic contact within the composite positive electrode becomes better, thereby improving the electrochemical performance.

[0225] In some embodiments, the weight percentage of non-carbon conductive substances in the positive electrode active material layer is moderate (e.g., 1.8wt% to 2.2wt%, further such as 2wt%), which ensures sufficient electron conduction in the composite positive electrode without affecting ion conduction, and has better overall electrochemical performance.

[0226] In some comparative examples, in the case of not adding a non-carbon conductive material and only using a carbon conductive material as the positive electrode conductive agent, as the amount of the carbon conductive material increases, the performance of the all-solid-state battery deteriorates significantly. Under the same amount of the positive electrode conductive agent, the electrochemical performance of the all-solid-state battery using a non-carbon conductive material (such as Se) as the positive electrode conductive agent is better than that of the all-solid-state battery using only a carbon conductive material (such as Super P) as the positive electrode conductive agent.

[0227] In some embodiments, the positive electrode solid electrolyte includes a sulfide solid electrolyte. Using a non-carbon conductive material (such as Se) as the positive electrode conductive agent significantly improves the electrochemical performance of the all-solid-state battery, and it is also confirmed that the non-carbon conductive material (such as Se) can inhibit the decomposition of the sulfide solid electrolyte.

[0228] In some embodiments, on the basis of the non-carbon conductive material, adding a small amount of the carbon conductive material, the all-solid-state battery can still maintain good electrochemical performance, which is much better than the electrochemical performance of the all-solid-state battery using only the carbon conductive material as the positive electrode conductive agent.

[0229] In some embodiments, the positive electrode solid electrolyte includes a sulfide solid electrolyte. When adding a small amount of the carbon conductive material on the basis of the non-carbon conductive material, the battery performance when using carbon nanotubes as the carbon conductive material is better than that when using Super P, because the carbon nanotubes are slender and have a smaller contact area with the sulfide solid electrolyte, so the decomposition effect on the sulfide solid electrolyte is less than that of Super P.

[0230] In some embodiments, reducing the particle size of the sulfide solid electrolyte will improve the ionic contact in the composite positive electrode, and the capacity, rate performance, and cycle performance of the battery will all be improved accordingly.

[0231] In some embodiments, reducing the particle size of the positive electrode active material shortens the diffusion path inside the positive electrode, and the discharge capacity of the battery will increase. In some other embodiments, when increasing the particle size of the positive electrode active material, the larger positive electrode material can be better wrapped by the positive electrode solid electrolyte (such as a sulfide solid electrolyte), and the contact with the positive electrode solid electrolyte will be better, and the cycle performance of the battery is improved.

[0232] In some embodiments, the lithium transition metal oxide in the positive electrode active material has a high nickel content (Q Ni ≥0.9, such as Q Ni =0.93), extremely high battery capacity can be obtained, and it still has good rate performance and cycle performance.

[0233] In some embodiments, the positive electrode film provided in the present application has good adaptability to a variety of different lithium transition metal oxides.

[0234] In some embodiments, the positive electrode film provided in the present application has good adaptability to a variety of different positive electrode solid electrolytes (such as different sulfide electrolytes), and all-solid-state batteries assembled therefrom have excellent electrochemical performance.

[0235] In some embodiments, when a sulfide solid electrolyte with high ionic conductivity is used as the positive electrode solid electrolyte, compared with only using a halide solid electrolyte or a combination of a halide solid electrolyte and a sulfide solid electrolyte, the all-solid-state battery using only the sulfide solid electrolyte as the positive electrode solid electrolyte has better electrochemical performance.

[0236] In some embodiments, the positive electrode film is formed into a positive electrode film layer by powder pressing on a solid electrolyte sheet, or made into an independent positive electrode film sheet. All-solid-state batteries assembled by both methods have excellent electrochemical performance. There is no limitation on the forming method of the positive electrode film, and they all have good adaptability.

[0237] In some embodiments, without using a binder, the positive electrode film is formed into a positive electrode film layer by powder pressing on a solid electrolyte sheet, and the assembled all-solid-state battery is very good.

[0238] In the present application, regarding the electrochemical performance of the battery, unless otherwise specified, it generally includes the comprehensive performance in terms of capacity, rate performance, and cycle performance.

[0239] In the present application, unless otherwise stated, an "all-solid-state battery cell" refers to a basic unit capable of converting chemical energy and electrical energy into each other, and all its components are solid.

[0240] Non-limitingly, an all-solid-state battery cell may include a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, and the solid electrolyte layer is located between the positive electrode layer and the negative electrode layer. During the charge and discharge process of the battery, active ions are embedded and extracted back and forth between the positive electrode layer and the negative electrode layer. The solid electrolyte layer plays a role in conducting ions between the positive electrode layer and the negative electrode layer, and can also isolate the positive electrode layer and the negative electrode layer to prevent short circuit between the positive and negative electrodes.

[0241] Unless otherwise stated, the positive electrode layer in an all-solid-state battery includes the positive electrode film described in the first aspect of the present application. It may be composed only of the positive electrode film described in the first aspect of the present application, or the positive electrode film described in the first aspect of the present application may be compounded with other films suitable for the positive electrode to form the positive electrode layer.

[0242] The following are some descriptions about the negative electrode layer.

[0243] The negative electrode layer can be provided by a negative electrode sheet or a negative electrode film that can be used in the field of all-solid-state batteries in the art. Alternatively, the constituent materials of the negative electrode layer can be directly pressed into a negative electrode film layer on one surface of the solid electrolyte layer. The negative electrode film can be compounded with other films suitable for the negative electrode to form a negative electrode sheet or a negative electrode layer.

[0244] The negative electrode layer can be prepared by a dry method or a wet method. For example, it can be pressed into a film by a dry method. Alternatively, it can be coated into a film by a wet method.

[0245] The negative electrode layer includes a negative electrode active material layer, and the negative electrode active material layer includes a negative electrode active substance.

[0246] Non-limitingly, the weight percentage of the negative electrode active substance in the negative electrode active material layer can be ≥80 wt%, and further can be ≥90 wt%.

[0247] In some embodiments, the negative electrode active substance is a lithium-indium alloy (InLi alloy).

[0248] In some embodiments, the negative electrode layer is an InLi alloy film.

[0249] In some embodiments, the negative electrode active substance can also be a negative electrode active substance that is well-known in the art and can be used in all-solid-state batteries. As non-limiting examples, the negative electrode active substance can include one or more of the following materials: elemental silicon, elemental tin, silicon-carbon negative electrode, silicon monoxide, graphite, metallic lithium. However, the present application is not limited to these materials or substances, and other conventional materials that can be used as the negative electrode active substance of the battery can also be used. These negative electrode active substances can be used alone, or two or more of them can be used in combination.

[0250] In some embodiments, the negative electrode tab or the negative electrode film may include a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector. The negative electrode active material layer includes a negative electrode active material. As a non-limiting example, the negative electrode current collector has two surfaces facing away from each other in its own thickness direction, and the negative electrode active material layer is provided on any one or both of the two surfaces of the negative electrode current collector facing away from each other. In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, copper foil may be used. In the negative electrode current collector, the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate. In the negative electrode current collector, the composite current collector may be formed by forming a metal material on the polymer material substrate. In the negative electrode current collector, non-limiting examples of the metal material may include one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc. In the negative electrode current collector, non-limiting examples of the polymer material substrate may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0251] In some embodiments, the negative electrode active material layer optionally includes a negative electrode conductive agent. Non-limitingly, the negative electrode conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In the negative electrode active material layer, the weight percentage of the negative electrode conductive agent may be 0 to 15 wt%, further optionally 0 to 10 wt%, and still further optionally 0 to 5 wt%.

[0252] In some embodiments, the negative electrode active material layer optionally includes other additives, such as thickeners (such as sodium carboxymethyl cellulose (CMC-Na)), etc. The weight percentage of the other additives in the negative electrode active material layer may be 0 to 15 wt%, further optionally 0 to 10 wt%, still further optionally 0 to 5 wt%, still further optionally 0 to 3 wt%, and still further optionally 0 to 2 wt%.

[0253] In some embodiments, the negative electrode sheet or negative electrode film can be prepared in the following manner: The various components used for preparing the negative electrode sheet or negative electrode, such as the negative electrode active material, negative electrode conductive agent, binder, and any other components, are dispersed in a solvent (non-limiting examples of the solvent include N-methylpyrrolidone (NMP)) to form a negative electrode slurry. Further, the negative electrode slurry is coated on at least one surface of the negative electrode current collector, and after processes such as drying and cold pressing, the negative electrode sheet or negative electrode film can be obtained. Cold pressing can be carried out using a cold rolling mill. The surface of the negative electrode current collector coated with the negative electrode slurry can be a single surface of the negative electrode current collector or two surfaces of the negative electrode current collector. The solid content of the negative electrode slurry can be 30 wt% to 70 wt%, and can be optionally 40 wt% to 60 wt%. The viscosity of the negative electrode slurry at room temperature can be adjusted to 2000 mPa·s to 10000 mPa·s, and can be optionally 3000 mPa·s to 10000 mPa·s. When coating the negative electrode slurry, the coating unit surface density in terms of dry weight (deducting the solvent) can be 75 g / m 2 ~220 g / m 2 . The tap density of the negative electrode sheet or negative electrode film can be 1.0 g / cm 3 ~2.0 g / cm 3 , 1.0 g / cm 3 ~1.8 g / cm 3 .

[0254] The following are some descriptions about the solid electrolyte layer.

[0255] The solid electrolyte layer plays a role in conducting ions between the positive electrode layer and the negative electrode layer, and can also isolate the positive electrode layer and the negative electrode layer to prevent short circuit between the positive and negative electrodes.

[0256] The solid electrolyte layer includes a solid electrolyte. The solid electrolyte in the solid electrolyte layer can be a solid electrolyte known in the art that can be used in all-solid-state batteries. As non-limiting examples, the solid electrolyte in the solid electrolyte layer can include one or more of the following materials: sulfide solid electrolytes, halide solid electrolytes, oxide solid electrolytes, polymer solid electrolytes, etc. The type of sulfide solid electrolyte in the solid electrolyte layer can be the same as or different from the sulfide solid electrolyte in the positive electrode layer (such as the aforementioned positive electrode film).

[0257] In some embodiments, the solid electrolyte layer can be formed by pressing a solid electrolyte material into a solid electrolyte film.

[0258] In some embodiments, the thickness of the solid electrolyte layer can be 0.1 μm to 1000 μm, and can be optionally thicknesses such as 10 μm to 100 μm, 100 μm to 800 μm, 500 μm to 800 μm, etc.

[0259] Non-limitingly, the positive electrode film, the solid electrolyte film, and the negative electrode film can be stacked in sequence, with the solid electrolyte placed between the positive electrode film and the negative electrode film, and a all-solid-state battery cell can be prepared by hot roll pressing.

[0260] In some embodiments, the all-solid-state battery single body includes an all-solid-state battery cell.

[0261] In some embodiments, the all-solid-state battery cell 52 includes a positive electrode layer 200, a solid electrolyte layer 100, and a negative electrode layer 300 stacked in sequence. For one example, reference can be made to Figure 5 . Unless otherwise specified, the positive electrode layer 200 includes a positive electrode film 20.

[0262] In some embodiments, the all-solid-state battery cell 52 includes a positive electrode layer 200, a solid electrolyte layer 100, and a negative electrode layer 300 stacked in sequence. Among them, the positive electrode layer 200 includes a positive electrode film 20, the positive electrode film 20 includes a positive electrode current collector 210 and positive electrode active material layers 220 located on both sides of the positive electrode current collector, and a positive electrode active material layer 220 is disposed between the positive electrode current collector 210 and the solid electrolyte layer 100. For one example, reference can be made to Figure 6 .

[0263] In some embodiments, the all-solid-state battery may include an outer package. The outer package can be used to encapsulate the above-mentioned all-solid-state battery cell.

[0264] In some embodiments, the outer package of the all-solid-state battery can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer package of the all-solid-state battery can also be a soft package, such as a pouch soft package. The material of the soft package can be plastic. Further, non-limiting examples of the plastic can include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate, etc.

[0265] The all-solid-state battery includes at least one all-solid-state battery single body. The all-solid-state battery can include 1 or more all-solid-state battery single bodies.

[0266] This application does not particularly limit the shape of the all-solid-state battery single body, and it can be cylindrical, square, or any other arbitrary shape. For example, Figure 7 is an all-solid-state battery single body 5 with a square structure as an example.

[0267] In some of these embodiments, with reference to Figure 8, the outer package may include a housing 51 and a cover plate 53. Among them, the housing 51 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose to form a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The all-solid-state battery cell 52 is encapsulated in the receiving cavity. The number of all-solid-state battery cells 52 included in the all-solid-state battery single body 5 can be one or more, and those skilled in the art can select according to actual needs.

[0268] The all-solid-state battery can be a battery module 4 or a battery pack 1.

[0269] The battery module includes at least one all-solid-state battery single body. The number of all-solid-state battery single bodies included in the battery module can be one or more, and those skilled in the art can select a suitable number according to the application and capacity of the battery module.

[0270] Figure 9 is the battery module 4 as an example. Refer to Figure 9 , in the battery module 4, a plurality of all-solid-state battery single bodies 5 can be arranged in sequence along the length direction of the battery module 4. Of course, they can also be arranged in any other way. Further, the plurality of all-solid-state battery single bodies 5 can be fixed by fasteners.

[0271] Optionally, the battery module 4 may further include a housing having a receiving space, and a plurality of all-solid-state battery single bodies 5 are received in the receiving space.

[0272] In some embodiments, the above battery module can also be assembled into a battery pack. The number of battery modules included in the battery pack can be one or more, and those skilled in the art can select a suitable number according to the application and capacity of the battery pack.

[0273] Figure 10 and Figure 11 is the battery pack 1 as an example. Refer to Figure 10 and Figure 11 , in the battery pack 1, it may include a battery box and a plurality of battery modules 4 arranged in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can be covered on the lower box body 3 and form a closed space for receiving the battery module 4. The plurality of battery modules 4 can be arranged in the battery box in any way.

[0274] In some embodiments, the electrical device includes the all-solid-state battery according to any of the embodiments provided in the present application.

[0275] Non - restrictively, all - solid - state batteries can be used as a power source for electrical devices or as an energy storage unit for electrical devices. Electrical devices can include, but are not limited to, mobile devices, electric vehicles, electric trains, ships, satellites, energy storage systems, etc. Among them, mobile devices can be, for example, mobile phones, laptops, etc.; electric vehicles can be, for example, pure electric vehicles, hybrid electric vehicles, plug - in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, electric motorcycles, power tools, etc., but are not limited to these. The electrical devices can also be applied to fields such as military equipment, aerospace, etc., and can also be applied to energy storage power systems such as hydro - power, thermal - power, wind - power, and solar - power stations.

[0276] As an electrical device, an all - solid - state battery can be selected according to its usage requirements.

[0277] Figure 12 Electrical device 6 is taken as an example. The electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug - in hybrid electric vehicle, etc. In order to meet the high - power and high - energy - density requirements of the electrical device for the all - solid - state battery, a battery pack or a battery module can be adopted.

[0278] Another example of the device can be a mobile phone, a tablet computer, a laptop, etc. This device usually requires being thin and light, and an all - solid - state battery can be used as the power source.

[0279] Hereinafter, some embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application. For those without specified techniques or conditions in the embodiments, they are carried out according to the descriptions above, or according to the techniques or conditions described in the literature in this field, or according to the product specifications. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase, or can be synthesized from commercially available products in a conventional manner. For example, the Se / Te composite involved is prepared by the following method: Weigh Se powder and Te powder according to the stoichiometric ratio, vacuum - seal them in a quartz tube, with a vacuum degree of about 10 -5 Torr, and then heat at 900 °C to obtain a uniformly - mixed melt, and quench the melt in ice water to obtain a Se / Te composite (selenium - tellurium alloy) with a specific atomic ratio.

[0280] Unless otherwise specified, in the following embodiments and comparative examples, raw materials with the same chemical formula come from the same synthesis batch or the same product number of raw materials, or are prepared according to the same stoichiometric ratio and in the same method.

[0281] In the following embodiments, room temperature refers to 20 °C to 30 °C.

[0282] D vTest of 50:

[0283] In the following examples and comparative examples, the D of the positive electrode active material, sulfide solid electrolyte, and non-carbon conductive material v 50 was tested and confirmed by the following method: Equipment model: Malvern 2000 (MasterSizer 2000) laser particle size analyzer, reference standard process: GB / T 19077-2016 / ISO 13320:2009, specific test process: Take an appropriate amount of the sample to be tested (the sample concentration should ensure a light transmittance of 8%-12% (w / v)), add 20 mL of deionized water, and ultrasonicate externally for 5 min (53 KHz / 120 W) to ensure complete dispersion of the sample. Then, the sample was measured according to the standard of GB / T 19077-2016 / ISO 13320:2009.

[0284] Example 1.

[0285] (1) Preparation of the positive electrode film (as the positive electrode plate):

[0286] Take LiNi 0.83 Co 0.12 Mn 0.05 O2 positive electrode active material (D v 50 is 4 μm), Li6PS5Cl sulfide solid electrolyte (D v 50 is 1 μm), Se powder (D v 50 is about 50 nm), and the binder polytetrafluoroethylene (PTFE) were weighed according to the mass ratio of 85:12:2:1. The raw materials were mixed evenly in a double planetary mixer, and then the evenly mixed powder was heated and pressed in a kneader to form a dough-like material. Then, it was hot roll-pressed at 80 °C into a self-supporting positive electrode sheet, and finally heat roll-compounded with the current collector aluminum (Al) foil to obtain the positive electrode plate. The formed positive electrode active material layer is located on one side of the positive electrode film, the thickness of the aluminum foil is about 12 μm, and the thickness of the positive electrode film is 100 μm.

[0287] (2) Solid electrolyte film (as the solid electrolyte layer)

[0288] Weigh 100 mg of the sulfide solid electrolyte Li6PS5Cl, add it to the battery mold, and press to obtain an electrolyte sheet with a thickness of 600 μm.

[0289] (3) Negative electrode film (as the negative electrode plate)

[0290] Select the InLi alloy film as the negative electrode film.

[0291] (4) Assemble the all-solid-state battery

[0292] Stack the positive electrode membrane on one side of the solid electrolyte sheet, stack the InLi alloy membrane on the other side as the negative electrode membrane, and assemble it into a all-solid-state battery under a pressure of 360 MPa.

[0293] Examples 2 to 23 prepared all-solid-state batteries using substantially the same method as Example 1. The differences can be referred to Tables 1 to 3, where one or more of the following parameters are different: the composition of the positive electrode conductive agent (including the type of non-carbon conductive substance, the D v 50, the weight percentage of the non-carbon conductive substance in the positive electrode active material layer, the weight percentage of the carbon conductive substance relative to the non-carbon conductive substance, the weight percentage of the carbon conductive substance in the positive electrode active material layer, and the type of carbon conductive substance), the composition of the positive electrode solid electrolyte (including the type of sulfide solid electrolyte, the D v 50, and the weight percentage of the sulfide solid electrolyte in the positive electrode active material layer), the composition of the positive electrode active material (including the type of lithium transition metal oxide, the D v 50, and the weight percentage of the lithium transition metal oxide in the positive electrode active material layer), and the type of positive electrode membrane (being a positive electrode membrane layer or a positive electrode membrane sheet).

[0294] Example 24. Positive electrode membrane layer form

[0295] Mix LiNi 0.83 Co 0.12 Mn 0.05 O2 positive electrode active material (D v 50 is 4 μm), Li6PS5Cl sulfide solid electrolyte (D v 50 is 1 μm), and Se powder (D v 50 is about 50 nm) evenly at a mass ratio of 85:12:2 to obtain a composite positive electrode powder. When assembling the all-solid-state battery, sprinkle the composite positive electrode powder on one side of the solid electrolyte sheet, apply pressure to obtain a positive electrode membrane layer, then place InLi alloy on the other side of the solid electrolyte, and apply pressure at 360 MPa to obtain the all-solid-state battery. The remaining test methods are the same as those in Example 1.

[0296] Comparative Examples 1 to 4 used substantially the same method as Example 1, except that the non-carbon conductive substance was replaced with carbon black Super P with different contents of carbon conductive substance.

[0297] Comparative Example 5. Used substantially the same method as Example 1, except that the non-carbon conductive substance was replaced with carbon nanotubes with different contents of carbon conductive substance.

[0298] Table 1.

[0299]

[0300] Table 2

[0301]

[0302] Table 3

[0303]

[0304] In Tables 1, 2 and 3, the value of D v 50 is rounded for entry; among the values expressed as approximate numbers, "about 50 nm" means 50 ± 1 nm, and "about 100 nm" means 100 ± 2 nm; among the values not expressed as approximate numbers, the numerical deviation of the values in μm is within the range of ±0.2 μm.

[0305] Performance Test and Analysis:

[0306] The electrochemical performance of the positive electrode sheet and the corresponding all-solid-state battery was tested using a solid-state mold battery, and the battery test window was 2.8 V to 4.3 V (versus lithium potential).

[0307] 1. Initial Discharge Capacity

[0308] The test process is as follows: The assembled all-solid-state battery was charged to 3.68 V (versus lithium potential 4.3 V) at a current density of 0.1 C, allowed to stand for 10 min, and then discharged to 2.18 V (versus lithium potential 2.8 V) at a current density of 0.1 C to obtain the initial discharge capacity of the battery. The battery was tested at 25 ± 3 °C, where 1 C = 200 mA / g.

[0309] 2. Initial Coulombic Efficiency

[0310] Dividing the initial discharge capacity obtained by testing at 0.1 C by the initial charge capacity gives the initial Coulombic efficiency of the battery.

[0311] 3. Rate Performance

[0312] The test process is as follows: The charge rate of the all-solid-state battery was fixed at 0.1 C, and then discharged at rates of 0.1 C, 0.33 C, 1 C, 2 C, and 3 C respectively. Each rate was cycled 3 times, and the battery voltage test window was 2.8 - 4.3 V vs.Li + / Li, and the battery was tested at 25 ± 3 °C, where 1 C = 200 mA / g.

[0313] 4. Cycle Performance:

[0314] The test process is as follows: The assembled all-solid-state battery is first charged and discharged at 0.1C for 3 cycles for activation, and then charged and discharged at 0.33C for long-cycle testing for 200 cycles. The cycle capacity retention rate of the battery is calculated. The voltage test window of the battery is 2.8 - 4.3V vs. Li + / Li (versus lithium potential, the active ion is Li + ), and the battery is tested at 25 ± 3°C, where 1C = 200 mA / g. The test results can be referred to "Capacity retention rate at 200 cycles, 0.33C" in Table 4.

[0315] Test analysis results:

[0316] The test results of the electrochemical performance of the all-solid-state batteries of each example and each comparative example can be referred to Table 4.

[0317] For the comparison of the first charge-discharge curves of Comparative Example 1 and Example 1, refer to Figure 13 . It can be seen that by using Se powder to replace the traditional Super P carbon conductive agent, the decomposition of the sulfide electrolyte is inhibited, and the first discharge capacity, Coulomb efficiency, cycle performance, and rate performance of the all-solid-state battery are significantly improved.

[0318] In Comparative Examples 1 - 5, traditional carbon conductive materials are used as the positive electrode conductive agent. Compared with Examples 1 - 24, the first discharge capacity, Coulomb efficiency, cycle performance, and rate performance of the all-solid-state batteries in Comparative Examples 1 - 5 are significantly worse.

[0319] Example 2 uses Te powder with high electronic conductivity as the positive electrode conductive agent, and the assembled all-solid-state battery has good electrochemical performance;

[0320] In the non-carbon conductive materials of Examples 3 - 6, both Se element and Te element are contained. The discharge capacity, rate performance, and cycle performance of the all-solid-state battery are significantly improved compared with Comparative Example 1. Due to the synergistic effect between Se and Te, Se element is more likely to combine with peroxide ions to form SeO3 2- , which is more conducive to inhibiting the decomposition of the sulfide electrolyte; Te element can endow the non-carbon conductive material with higher electronic conductivity and provide more sufficient electron conduction channels. At this time, when the non-carbon conductive material is Se x Te 1-x complex or when Se and Te are mixed and added, the all-solid-state battery has very good electrochemical performance. In addition, Se x Te 1-x in the complex are combined at the atomic scale, and the effect of the combined use of the two elements is very excellent.

[0321] In Examples 14-15, a small amount of carbon conductive material (second conductive material) is added to the non-carbon conductive material, and the all-solid-state battery can still maintain good electrochemical performance, and is far superior to the electrochemical performance of the all-solid-state battery using only carbon conductive material as the positive electrode conductor (such as Comparative Example 5). In addition, when the second conductive material is used, the carbon nanotubes are slender and have a small contact area with the sulfide solid electrolyte. When the second conductive material uses carbon nanotubes, it is beneficial to reduce the decomposition effect on the sulfide solid electrolyte.

[0322] The positive electrode film in Example 24 does not contain a binder, and the assembled all-solid-state battery is very good.

[0323] Table 4.

[0324]

[0325] The description of each embodiment above tends to emphasize the differences between each embodiment, and the same or similar parts can be referenced to each other. For the sake of brevity, this article will not repeat them. The technical features of the embodiments described above can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples. Within the scope of the technical solution of the present application, the embodiments with the same structure as the technical idea and the same effect are included in the technical scope of the present application. The embodiments described above only express several embodiments of the present application, and the description is relatively detailed, but it cannot be understood as a limitation on the scope of the patent. In addition, without departing from the scope of the subject matter of the present application, various deformations that can be thought of by those skilled in the art are applied to the embodiments, and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A positive electrode film, characterized in that, It includes a positive electrode active material layer, and the positive electrode active material layer includes a positive electrode active substance, a positive electrode solid electrolyte, and a positive electrode conductive agent; Among them, the positive electrode active material includes a lithium transition metal oxide, the positive electrode conductive agent includes a non-carbon conductive material, the non-carbon conductive material includes at least one of Se element, Te element and Se / Te composite, and the chemical formula of the Se / Te composite is Se x Te 1-x , 0 < x < 1.

2. The positive electrode film according to claim 1, characterized in that, At any temperature or within any temperature range from 20 °C to 100 °C, under the same test conditions, the electronic conductivity of the non-carbon conductive substance is greater than or equal to the electronic conductivity of the Se single substance.

3. The positive electrode film according to claim 1 or 2, characterized in that, The weight percentage of Te element in the non-carbon conductive substance is 50 wt% - 100 wt%.

4. The positive electrode film according to claim 1 or 2, characterized in that, The weight percentage of Te element in the non-carbon conductive substance is 60 wt% - 100 wt%.

5. The positive electrode film according to any one of claims 1 to 4, characterized in that, At least one of the Se single substance, Te single substance, and Se / Te composite is denoted as the first conductive substance, and the weight percentage of the first conductive substance in the non-carbon conductive substance is 80 wt% - 100 wt%.

6. The positive electrode film according to any one of claims 1 to 5, characterized in that, The D of the non-carbon conductive material v 50 is 1 nm to 20 μm; wherein, D v 50 represents the particle size corresponding to when the cumulative volume distribution percentage of the multi-particle mixture reaches 50%.

7. The positive electrode film according to claim 6, characterized in that, The D of the non-carbon conductive material v is 10 nm to 5 μm.

8. The positive electrode film according to claim 6, wherein, The D of the non-carbon conductive material v 50 is from 10 nm to 1 μm.

9. The positive electrode film according to any one of claims 1 to 8, characterized in that, The weight percentage of the non-carbon conductive substance in the positive electrode active material layer is 0.1 wt% - 10 wt%.

10. The positive electrode film according to claim 9, characterized in that, The weight percentage of the non-carbon conductive substance in the positive electrode active material layer is 0.5 wt% - 5 wt%.

11. The positive electrode film according to any one of claims 1 to 10, characterized in that, The positive electrode solid electrolyte includes a sulfide solid electrolyte.

12. The positive electrode film according to any one of claims 1 to 11, characterized in that, The positive electrode conductive agent includes or does not include a carbon conductive substance, and the carbon conductive substance satisfies at least one of the following characteristics: The weight percentage of the carbon conductive substance relative to the non-carbon conductive substance is 0 wt% - 50 wt%; The weight percentage of the carbon conductive substance in the positive electrode active material layer is 0 wt% - 1 wt%; The carbon conductive substance includes one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

13. The positive electrode film according to claim 12, characterized in that, The carbon conductive substance satisfies at least one of the following characteristics: The weight percentage of the carbon conductive substance relative to the non-carbon conductive substance is 0 wt% - 33 wt%; The weight percentage of the carbon conductive substance in the positive electrode active material layer is 0 wt% - 0.5 wt%.

14. The positive electrode film according to any one of claims 11 to 13, characterized in that, The sulfide solid electrolyte includes at least one of a binary sulfide solid system and a ternary sulfide solid system.

15. The positive electrode film according to claim 14, wherein, The sulfide solid electrolyte satisfies at least one of the following characteristics: The binary sulfide solid system includes one or more of Li2S-P2S5, Li2S-SiS2, Li2S-GeS2, and Li2S-B2S3; The ternary sulfide solid system includes one or more of argyrodite-type sulfide electrolytes, Li2S-MeS2-P2S5 ternary sulfide electrolytes, lithium germanium phosphorus sulfide-type sulfide electrolytes, Li2S-P2S5-MS ternary sulfide electrolytes, Li2S-P2S5-MCl ternary sulfide electrolytes, and thio-LISICON-type sulfide electrolytes; wherein, Me includes one or more elements of Si, Ge, Sn, and Al; M includes one or more elements of Ge, Al, Sn, Pb, Sb, Si, and As.

16. The positive electrode film according to any one of claims 11 to 15, characterized in that, The D of the sulfide solid electrolyte v 50 is from 1 nm to 20 μm; wherein, D v 50 represents the particle size corresponding to when the cumulative volume distribution percentage of the multi-particle mixture reaches 50%.

17. The positive electrode film according to claim 16, characterized in that, The D of the sulfide solid electrolyte v 50 is 50 nm to 5 μm.

18. The positive electrode film according to any one of claims 11 to 17, characterized in that The weight percentage of the sulfide solid electrolyte in the positive electrode active material layer is 0.1 wt% - 30 wt%.

19. The positive electrode film according to claim 18, wherein The weight percentage of the sulfide solid electrolyte in the positive electrode active material layer is 5 wt% - 20 wt%.

20. The positive electrode film according to any one of claims 1 to 19, characterized in that, The lithium transition metal oxide includes one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium-rich manganese positive electrode active material, and modified forms of any one of the foregoing positive electrode active materials; wherein, the chemical formula of the lithium-rich manganese positive electrode active material is qLi2MnO3-(1-q)LiZO2, Z includes one or more elements selected from Ni, Co, Mn, Cr, Fe, Al, Nb, Mo, and Ru, and 0≤q≤1; the modified forms include one or more of doping modification and coating modification.

21. The positive electrode film according to any one of claims 1 to 20, characterized in that, The D of the lithium transition metal oxide v 50 is 0.1 μm to 20 μm.

22. The positive electrode film according to claim 21, characterized in that, The D of the lithium transition metal oxide v is 1 μm to 10 μm.

23. The positive electrode film according to any one of claims 1 to 22, characterized in that, The weight percentage of the lithium transition metal oxide in the positive electrode active material layer is 70wt% to 99wt%.

24. The positive electrode film according to claim 23, characterized in that, The weight percentage of the lithium transition metal oxide in the positive electrode active material layer is 80wt% to 95wt%.

25. The positive electrode film according to any one of claims 1 to 24, characterized in that, The thickness of the positive electrode active material layer is 30μm to 400μm.

26. The positive electrode film according to claim 25, characterized in that, The thickness of the positive electrode active material layer is 60μm to 130μm.

27. The positive electrode film according to any one of claims 1 to 26, characterized in that, The positive electrode film includes a positive electrode current collector and the positive electrode active material layer, and the positive electrode active material layer is located on at least one side of the positive electrode current collector.

28. A positive electrode active material layer, characterized in that, It is the positive electrode active material layer in the positive electrode film according to any one of claims 1 to 26.

29. A positive electrode membrane sheet, characterized in that, It includes a positive electrode current collector and a positive electrode active material layer located on at least one side of the positive electrode current collector, and the positive electrode active material layer is the positive electrode active material layer in the positive electrode film according to any one of claims 1 to 26.

30. A all-solid-state battery, characterized in that, It includes at least one of the positive electrode film according to any one of claims 1 to 27 and the positive electrode film sheet according to claim 27.

31. An electrical device, characterized in that, It includes the all-solid-state battery according to claim 30.

32. The application of the positive electrode film according to any one of claims 1 to 27 as a positive electrode film sheet in the preparation of an all-solid-state secondary battery or as a positive electrode film layer in an all-solid-state secondary battery, or the application of the positive electrode film sheet according to claim 29 in the preparation of an all-solid-state secondary battery.

33. Application of a non-carbon conductive material as a conductive agent in the positive electrode layer of an all-solid-state battery, characterized in that, The positive electrode layer of the all-solid-state battery includes the positive electrode film according to any one of claims 1 to 27, and the non-carbon conductive material is the non-carbon conductive material in the positive electrode film.

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