Positive electrode film, positive electrode film sheet, solid-state battery, electric device, and application

Abstract

A positive electrode film, a positive electrode film sheet, a solid-state battery, an electric device, and an application. The positive electrode film comprises a positive electrode active material layer; the positive electrode active material layer comprises a positive electrode active material, a positive electrode solid-state electrolyte, and a conductive agent; the positive electrode active material comprises an oxide positive electrode active material; the conductive agent comprises a non-carbon conductive material; and the non-carbon conductive material includes at least one of elemental Se, elemental Te, and a Se / Te complex SexTe1-x, and 0<X<1.

Description

Cathode film, cathode membrane, solid-state battery, electrical device and application

[0001] Related applications

[0002] This application claims priority to the Chinese patent application filed on December 28, 2023, with application number CN2023118438880 and entitled “Positive electrode film, positive electrode membrane, all-solid-state battery, electrical device and application”, the entire text of which is hereby incorporated by reference. Technical Field

[0003] The present application relates to the field of solid-state battery technology, in particular to the field of all-solid-state battery technology, and further to a positive electrode film, a positive electrode diaphragm, a solid-state battery, an electrical device and an application, wherein the solid-state battery includes an all-solid-state battery. Background Art

[0004] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0005] Solid-state batteries use non-flammable solid electrolytes to replace the organic electrolytes in traditional liquid secondary batteries, which greatly improves the safety of the batteries and is considered to be the new generation of batteries closest to industrialization. An all-solid-state battery is a solid-state battery that uses solid electrodes and solid electrolytes. An all-solid-state battery uses a solid electrolyte to replace the liquid electrolyte in a traditional battery, and the solid electrolyte can also simultaneously isolate the positive and negative electrodes, so an isolation membrane is not required. In view of the advantages of all-solid-state batteries in terms of safety and energy density, all-solid-state batteries have received widespread attention in recent years. However, in solid-state batteries (such as all-solid-state batteries), poor interface contact and interface side reaction problems are one of the pain points that limit their performance, resulting in unsatisfactory discharge capacity, rate performance and cycle performance of the battery.

[0006] Summary of the Invention

[0007] According to various embodiments and examples of the present application, the present application provides a positive electrode film, a positive electrode membrane, a solid-state battery, an electrical device, and an application, wherein the solid-state battery includes an all-solid-state battery. The positive electrode film can be used as a positive electrode membrane to prepare a solid-state battery (such as an all-solid-state battery) having high discharge capacity, high rate performance, and good cycle performance, and can also be used as a positive electrode membrane layer in a solid-state battery (such as an all-solid-state battery).

[0008] In a first aspect, the present application provides a positive electrode film, which includes a positive electrode active material layer, the positive electrode active material layer including a positive electrode active material, a positive electrode solid electrolyte and a positive electrode conductive agent;

[0009] Among them, the positive electrode active material includes an oxide positive electrode active material, the positive electrode conductive agent includes a non-carbon conductive material, the non-carbon conductive material includes at least one of Se单质, Te单质 and Se / Te composite, and the chemical formula of the Se / Te composite is Se x Te 1-x , 0 < x < 1. In some embodiments, the oxide positive electrode active material includes a lithium transition metal oxide.

[0010] In some embodiments, a positive electrode film is provided, which includes a positive electrode active material layer, and the positive electrode active material layer includes a positive electrode active material, a positive electrode solid electrolyte and a positive electrode conductive agent;

[0011] 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单质, Te单质 and Se / Te composite, and the chemical formula of the Se / Te composite is Se x Te 1-x , 0 < x < 1.

[0012] This positive electrode film adopts the mode of a composite positive electrode, which includes a positive electrode active material, a solid electrolyte (also denoted as a positive electrode solid electrolyte) and a conductive agent (also denoted as a positive electrode conductive agent). The addition of the solid electrolyte and the conductive agent can respectively enhance the ion conduction ability and the electron conduction ability on the positive electrode side, promote the charge transfer efficiency between the positive electrode active material and the outside and the full release of its capacity. Among them, the positive electrode conductive agent can improve the electron conduction ability in the positive electrode film, thereby improving 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 Se单质, Te单质 and Se / Te composite, and is composed of one or two of the elements selenium (Se) and tellurium (Te). Among them, both Se单质 and Te单质 have high electronic conductivity. The electronic conductivity of Se单质 is about 10 mS / cm, and the electronic conductivity of Te单质 is about 2000 mS / cm, so that the non-carbon conductive material can be used as a conductive material in the positive electrode film and can provide good electron conduction ability. In addition, within the electrochemical working window of the oxide positive electrode active material (such as a lithium transition metal oxide), selenium (Se) and tellurium (Te) have almost no electrochemical activity and can basically not participate in electrochemical reactions, thus maintaining a stable electron conduction ability. When a non-carbon conductive material is introduced as a conductive agent, when charging to a high voltage, the peroxide ions (O2 2- ) or oxygen free radicals generated can react with Se and / or Te in the non-carbon conductive material to generate SeO3 2- and / or TeO3 2-This reaction can inhibit the release of oxygen from oxide cathode active materials (such as lithium transition metal oxides), improving the structural stability of the cathode active materials and the electrochemical performance of the battery. Therefore, by introducing non-carbon conductive materials into the cathode film, the resulting solid-state battery (such as an all-solid-state battery) can simultaneously exhibit high discharge capacity, high rate performance, and good cycling performance.

[0013] By utilizing the multiple synergistic effects between oxide positive electrode active materials (such as 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 materials and the outside world and the full release of their capacity, and can be used to prepare solid-state batteries (such as all-solid-state batteries) with high discharge capacity, high rate performance and good cycle performance.

[0014] Based on any suitable embodiment of the present application, in some embodiments, at at least one temperature of 20° C. to 100° C. or at least a portion of the 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;

[0015] Optionally, at any temperature between 20° C. and 100° C. or within 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.

[0016] 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.

[0017] Based on any appropriate embodiment of the present application, in some embodiments, the weight percentage of the Te element in the non-carbon conductive material is 50 wt % to 100 wt %, and can be optionally 60 wt % to 100 wt %.

[0018] Te (Te) has a high electronic conductivity (approximately 2000 mS / cm), which is roughly the same order of magnitude as traditional carbon black (for example, carbon black has an electronic conductivity of approximately 10 S / cm to 100 S / cm), providing excellent electronic conductivity. By incorporating a higher proportion of Te into the non-carbon conductive material, the amount of conductive agent and non-carbon conductive material used in the positive electrode film can be reduced, thereby increasing the battery's energy density.

[0019] Based on any appropriate 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%.

[0020] By controlling the weight percentage of the first conductive material in the non-carbon conductive material, it is beneficial to better exert the role of the first conductive material in inhibiting the release of oxygen from the oxide positive electrode active material (such as lithium transition metal oxide), which is beneficial to prepare a solid-state battery (such as an all-solid-state battery) with higher discharge capacity, higher rate performance and better cycle performance.

[0021] Based on any suitable embodiment of the present application, in some embodiments, the D of the non-carbon conductive material v 50 is 1nm~20μm, optionally 10nm~5μm, further optionally 10nm~1μm; wherein, D v 50 represents the particle size corresponding to when the cumulative volume distribution percentage of the multi-particle mixture reaches 50%.

[0022] 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 improving the electrical contact between the positive electrode active materials in the electrode membrane, thereby promoting the capacity and rate performance of solid-state batteries (such as all-solid-state batteries). Relatively moderate particle sizes of non-carbon conductive materials are easier to manufacture.

[0023] 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 can be optionally 0.5 wt % to 5 wt %.

[0024] By controlling the weight percentage of non-carbon conductive materials 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, which is more conducive to enabling solid-state batteries (such as all-solid-state batteries) to achieve higher discharge capacity, higher rate performance and better cycle performance.

[0025] Based on any suitable embodiment of the present application, in some embodiments, the positive electrode solid electrolyte includes a sulfide solid electrolyte.

[0026] Sulfide solid electrolytes have excellent ion conductivity, which can better promote the efficient charge transfer between the positive electrode active material and the external environment and fully release its capacity. Selenium (Se) and tellurium (Te) are elements in the same group as sulfur (S), which makes the non-carbon conductive material and sulfide solid electrolytes highly compatible. Moreover, the lack of oxygen-containing functional groups on the surface of non-carbon conductive materials can reduce side reactions between the non-carbon conductive material and the sulfide solid electrolyte, which helps reduce interfacial impedance.

[0027] When charged to a high voltage, the oxide positive electrode active material (such as lithium transition metal oxide) may produce oxygen, which in turn attacks the sulfide solid electrolyte, leading to the decomposition of the sulfide solid electrolyte. When a sulfide solid electrolyte is introduced into a solid-state battery positive electrode using an oxide positive electrode active material (such as an all-solid-state battery positive electrode using lithium transition metal oxide) without using a non-carbon conductive material, the oxidative decomposition of the sulfide solid electrolyte easily leads to an increase in interfacial impedance, which in turn affects the discharge capacity and causes the battery's electrochemical performance to be unsatisfactory. The addition of a non-carbon conductive material can inhibit the oxidative decomposition of the sulfide solid electrolyte at high voltage and give full play to the excellent ion-conducting effect of the sulfide solid electrolyte. At this time, the multiple synergistic effects between the oxide positive electrode active material (such as lithium transition metal oxide), the sulfide solid electrolyte and the non-carbon conductive material can form a better and more stable electrical contact network in the positive electrode film, which is more conducive to 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 is also more conducive to preparing a solid-state battery (such as an all-solid-state battery) with a higher discharge capacity, higher rate performance and good cycle performance.

[0028] In addition, in traditional lithium-ion batteries, carbon conductive materials are generally used as conductive materials. However, for the positive electrode whose solid electrolyte includes a sulfide solid electrolyte and whose positive electrode active material includes an oxide positive electrode active material (such as 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 of traditional carbon conductive materials with sulfide solid electrolytes is poor, which leads to the traditional carbon conductive materials easily accelerating the decomposition of the sulfide electrolyte, thereby causing the increase of the interface impedance of the solid-state battery (such as an all-solid-state battery) and the deterioration of the battery cycle performance. There may be two reasons: First, traditional carbon conductive materials usually have a large specific surface area and too high electronic conductivity, which greatly increases the contact area with the sulfide solid electrolyte, resulting in an aggravated accelerated decomposition of the sulfide solid electrolyte; second, the surface of traditional carbon conductive materials generally contains oxygen-containing functional groups, which are easy to react with the sulfide solid electrolyte, thereby causing a large interface impedance. However, if the amount of traditional carbon conductive materials is simply reduced, the stability of the electrical contact network of the positive electrode will be affected, and thus the capacity and rate performance of solid-state batteries (such as all-solid-state batteries) will be affected.

[0029] In the present application, by introducing a non-carbon conductive material into the positive electrode film, the amount of traditional carbon conductive material in the positive electrode of a solid-state battery (such as an all-solid-state battery) can be replaced or reduced accordingly, and the accelerated decomposition of the sulfide solid electrolyte by the traditional carbon conductive material can be suppressed while achieving good electronic conductivity. By controlling the weight percentage of the non-carbon conductive material in the positive electrode active material layer, the amount of the traditional carbon conductive material can be replaced or reduced accordingly under the amount of conductive material usually required for the positive electrode film, and the solid-state battery (such as an all-solid-state battery) can have better comprehensive performance in terms of discharge capacity, rate performance and cycle performance while achieving a good and stable electrical contact network.

[0030] In addition, for the positive electrode membrane including an oxide positive electrode active material (such as lithium transition metal oxide) and a sulfide solid electrolyte, by controlling the weight percentage of the non-carbon conductive material 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 interface impedance while improving the structural stability of the positive electrode active material, and also inhibiting the oxidative decomposition of the sulfide solid electrolyte at high voltage, which is more conducive to enabling solid-state batteries (such as all-solid-state batteries) to achieve higher discharge capacity, higher rate performance and better cycle performance.

[0031] 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:

[0032] 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%;

[0033] 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;

[0034] 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.

[0035] By introducing non-carbon conductive materials into the positive electrode conductive agent, the amount of traditional carbon conductive materials can be replaced or reduced, and solid-state batteries (such as all-solid-state batteries) can be given higher discharge capacity, higher rate performance, and better cycle performance while achieving a good and stable electrical contact network. The non-carbon conductive materials provided in this application can partially or completely replace traditional carbon conductive materials, that is, less or no traditional carbon conductive materials can be added to the positive electrode film.

[0036] When non-carbon conductive materials partially replace traditional carbon conductive materials, the adverse effects of traditional carbon conductive materials can be better reduced and higher discharge capacity, higher rate performance and better cycle performance can be achieved by controlling the carbon conductive material within the aforementioned lower usage range, such as by controlling one or two parameters 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.

[0037] When non-carbon conductive materials completely replace traditional carbon conductive materials, that is, no traditional carbon conductive materials are added to the positive electrode membrane, then, while 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 it is also more conducive to improving the structural stability of the positive electrode active material, thereby achieving higher discharge capacity, higher rate performance and better cycle performance.

[0038] The common presence of traditional carbon conductive materials can easily accelerate the oxidative 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 role of non-carbon conductive materials can be exerted.

[0039] Based on any suitable embodiment of the present application, in some embodiments, the sulfide solid electrolyte includes at least one of a binary sulfide solid system and a ternary sulfide solid system;

[0040] Optionally, the binary sulfide solid state system includes one or more of Li2S-P2S5, Li2S-SiS2, Li2S-GeS2 and Li2S-B2S3;

[0041] Optionally, the ternary sulfide solid-state system includes one or more of an argyrodite-type sulfide electrolyte, a Li2S-MeS2-P2S5 ternary sulfide electrolyte, a lithium-germanium-phosphorus-sulfur type sulfide electrolyte, a Li2S-P2S5-MS ternary sulfide electrolyte, a Li2S-P2S5-MCl ternary sulfide electrolyte and a thio-LISICON-type sulfide electrolyte; wherein Me includes one or more elements of Si, Ge, Sn and Al; and M includes one or more elements of Ge, Al, Sn, Pb, Sb, Si and As.

[0042] In the case where the positive electrode of a solid-state battery (such as an all-solid-state battery) includes the aforementioned various sulfide solid electrolytes, the oxidative decomposition of the sulfide solid electrolyte under high voltage can be inhibited by introducing non-carbon conductive substances, thereby improving the discharge capacity, rate performance and cycle performance of the solid-state battery (such as an all-solid-state battery). In addition, the first coulombic efficiency of the solid-state battery (such as an all-solid-state battery) can also be improved.

[0043] Furthermore, the introduction of non-carbon conductive materials can partially or completely replace traditional carbon conductive materials, reduce the accelerated decomposition effect of traditional carbon conductive materials on sulfide solid electrolytes, and better inhibit the decomposition of sulfide solid electrolytes.

[0044] Based on any suitable embodiment of the present application, in some embodiments, D of the sulfide solid electrolyte v 50 is 1nm~20μm, and can be selected as 50nm~5μm; among them, D v 50 represents the particle size corresponding to when the cumulative volume distribution percentage of the multi-particle mixture reaches 50%.

[0045] By controlling the particle size of the sulfide solid electrolyte within the above range, it is beneficial to improve the overall ion conductivity of the sulfide solid electrolyte, provide a better electrical contact network, and take into account the manufacturing cost. The relatively small particle size of the sulfide solid electrolyte is conducive to improving the electrical contact between the positive electrode active materials in the electrode membrane, thereby promoting the capacity and rate performance of solid-state batteries (such as all-solid-state batteries). The relatively moderate particle size of the sulfide solid electrolyte is easier to manufacture.

[0046] 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 can be optionally 5 wt % to 20 wt %.

[0047] The weight percentage of the sulfide solid electrolyte in the positive electrode active material layer can be controlled within the aforementioned range, which is beneficial for providing better overall ion conductivity.

[0048] Based on any suitable embodiment of the present application, in some embodiments, the oxide positive electrode active material (such as lithium transition metal oxide) includes 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 manganese-rich positive electrode active material and one or more modified forms of any of the foregoing positive electrode active materials; wherein the chemical formula of the lithium manganese-rich positive electrode active material is qLi2MnO3-(1-q)LiZO2, Z includes one or more elements of Ni, Co, Mn, Cr, Fe, Al, Nb, Mo and Ru, 0≤q≤1; the modified form includes one or more of doping modification and coating modification.

[0049] Non-carbon conductive materials can be introduced into the positive electrode film containing the aforementioned different types of oxide positive electrode active materials (such as lithium transition metal oxides), thereby playing the aforementioned role of improving the discharge capacity, rate performance and cycle performance of solid-state batteries (such as all-solid-state batteries).

[0050] Based on any suitable embodiment of the present application, in some embodiments, the D v 50 is 0.1μm~20μm, and can be optionally 1μm~10μm.

[0051] By controlling the particle size of the oxide positive electrode active material (such as 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 active material and the sulfide solid electrolyte in the composite positive electrode. The smaller the size of the positive electrode active material, the shorter the transmission channel of active ions (such as lithium ions) inside the positive electrode active material, which is beneficial to the improvement of the discharge capacity of the positive electrode active material itself; the larger the size of the positive electrode active material, the better the interface contact with the sulfide solid electrolyte, and the better the cycle performance of the battery. The relatively moderate size of the positive electrode material can make the battery have both high discharge capacity and excellent cycle performance.

[0052] Based on any suitable embodiment of the present application, in some embodiments, the weight percentage of the oxide positive electrode active material (such as 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 %.

[0053] By controlling the weight percentage of the oxide positive electrode active material (such as lithium transition metal oxide) in the positive electrode active material layer within the above range, it is beneficial to achieve both high energy density and cycle stability.

[0054] When the positive electrode film also includes a sulfide solid electrolyte, by controlling the weight percentage of the oxide positive electrode active material (such as lithium transition metal oxide) in the positive electrode active material layer within the above range, it is also beneficial to achieve a balance between high energy density and reducing the oxidative decomposition of the sulfide solid electrolyte.

[0055] Based on any appropriate embodiment of the present application, in some embodiments, the thickness of the positive electrode active material layer is 30 μm to 400 μm, and optionally 60 μm to 130 μm.

[0056] For the positive electrode of a solid-state battery (such as 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 can easily lead to unsatisfactory discharge capacity and rate performance of the battery, and when the positive electrode (of the all-solid-state battery) is thicker, the above-mentioned shortcomings are more obvious. At this time, for a solid-state battery (such as an all-solid-state battery) assembled using the positive electrode film provided by this application, the improvement in discharge capacity and rate performance is more obvious.

[0057] In yet another 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.

[0058] In the second aspect of the present 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 the present application.

[0059] In a third aspect of the present application, a solid-state battery is provided, comprising at least one of the positive electrode film described in the first aspect of the present application and the positive electrode membrane described in the second aspect of the present application.

[0060] In the third aspect of the present application, an all-solid-state battery is also provided, which includes at least one of the positive electrode film described in the first aspect of the present application and the positive electrode membrane described in the second aspect of the present application.

[0061] In a fourth aspect of the present application, an electrical device is provided, which includes at least one of the aforementioned solid-state battery and the all-solid-state battery described in the third aspect of the present application.

[0062] In a fifth aspect of the present application, there is provided a use of the positive electrode film described in the first aspect of the present application as a positive electrode membrane in the preparation of a solid-state secondary battery or as a positive electrode membrane layer in a solid-state secondary battery, or a use of the positive electrode membrane described in the second aspect of the present application in the preparation of a solid-state secondary battery;

[0063] Optionally, the solid-state secondary battery is an all-solid-state secondary battery.

[0064] In a sixth aspect of the present application, a non-carbon conductive material is provided as a conductive agent in a positive electrode layer of a solid-state battery. The positive electrode layer of the solid-state battery includes the positive electrode film described in the first aspect of the present application, and the non-carbon conductive material is a non-carbon conductive material in the positive electrode film.

[0065] Optionally, the solid-state battery is an all-solid-state battery.

[0066] The positive electrode layer of a solid-state battery (such as an all-solid-state battery) can be prepared or provided by the aforementioned positive electrode film. In the positive electrode active material layer of the positive electrode film, the positive electrode active material includes an oxide positive electrode active material (such as a lithium transition metal oxide) that can provide a high energy density, and a positive electrode solid electrolyte with a certain ionic conductivity and a non-carbon conductive material with good electronic conductivity are also introduced; within the corresponding electrochemical window, the non-carbon conductive material has a very stable electronic conductivity; the non-carbon conductive material can also absorb oxygen that may be generated by the solidified oxide positive electrode active material (such as a lithium transition metal oxide), which can suppress the The release of oxygen from oxide positive electrode active materials (such as lithium transition metal oxides) can improve the structural stability of the positive electrode active materials, thereby improving battery performance; utilizing the multiple synergistic effects between oxide positive electrode active materials (such as 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 interfacial impedance, and promoting the charge transfer efficiency between the positive electrode active materials and the outside world and the full release of their capacity, which can be used to prepare solid-state batteries (such as all-solid-state batteries) with higher discharge capacity, higher rate performance and good cycle performance.

[0067] 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 material includes an oxide positive electrode active material (such as a lithium transition metal oxide) that can provide a high energy density, includes a sulfide solid electrolyte with excellent ionic conductivity, and also includes a non-carbon conductive material with good electronic conductivity; within the corresponding electrochemical window, the non-carbon conductive material not only has a very stable electronic conductivity, but is also compatible with the sulfide solid electrolyte, has little or no side reaction with the sulfide solid electrolyte, and can reduce the interface impedance; by utilizing the non-carbon conductive material to absorb the solidified oxide positive electrode active material (such as a lithium transition metal oxide), the positive electrode active material can generate a high energy density. Oxygen can not only inhibit the release of oxygen from oxide positive electrode active materials (such as lithium transition metal oxides) and improve the structural stability of the positive electrode active materials, but also inhibit the oxidative decomposition of sulfide solid electrolytes under high voltage and improve battery performance; by utilizing the multiple synergistic effects between oxide positive electrode active materials (such as lithium transition metal oxides), sulfide solid electrolytes and non-carbon conductive materials, 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 materials and the outside world and the full release of their capacity, and can be used to prepare solid-state batteries (such as all-solid-state batteries) with high discharge capacity, high rate performance and good cycle performance.

[0068] In addition, the positive electrode of the solid-state battery (such as an all-solid-state battery) can use less or no traditional carbon conductive materials, which can reduce the accelerated 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 solid-state battery (such as an all-solid-state battery).

[0069] 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 description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to better describe and illustrate the embodiments, examples or examples provided in this application, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the accompanying drawings should not be considered as limiting the scope of the disclosed application, the embodiments, examples or examples currently described, and any of the best modes of these applications currently understood. It should also be noted that the accompanying drawings are drawn in a simplified form and are only used to assist in the explanation of this application for convenience and clarity. The various dimensions of each component shown in the accompanying drawings are arbitrarily shown and may be accurate or not drawn to scale. For example, in order to make the illustration clearer, the dimensions of the components are appropriately exaggerated in some places in the accompanying drawings. Unless otherwise specified, the components in the drawings are not drawn to scale. The drawings of this application do not limit every dimension of each component. Moreover, the same figure numbers are used to represent the same components in all the drawings. In the drawings:

[0071] FIG1 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.

[0072] FIG2 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.

[0073] FIG3 is a schematic structural diagram of a positive electrode film according to an embodiment of the present application, wherein 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.

[0074] FIG4 is a schematic structural diagram of a positive electrode film according to an embodiment of the present application, wherein 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.

[0075] FIG5 is a schematic structural diagram of an all-solid-state battery cell according to an embodiment of the present application, wherein the all-solid-state battery cell includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked in sequence.

[0076] Figure 6 is a structural schematic diagram of an embodiment of the all-solid-state battery cell shown in Figure 5, which includes a positive electrode layer, a solid electrolyte layer and a negative electrode layer stacked in sequence, wherein the positive electrode layer includes 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 both sides of the positive electrode current collector, and a positive electrode active material layer is arranged between the positive electrode current collector and the solid electrolyte layer.

[0077] FIG7 is a schematic diagram of an all-solid-state battery cell according to an embodiment of the present application.

[0078] FIG8 is an exploded view of the all-solid-state battery cell according to one embodiment of the present application shown in FIG7 .

[0079] FIG9 is a schematic diagram of a battery module according to an embodiment of the present application.

[0080] FIG10 is a schematic diagram of a battery pack according to an embodiment of the present application.

[0081] FIG11 is an exploded view of the battery pack shown in FIG10 according to an embodiment of the present application.

[0082] FIG12 is a schematic diagram of an electrical device using an all-solid-state battery as a power source according to an embodiment of the present application.

[0083] FIG13 is a comparison of the first charge and discharge curves of Comparative Example 1 and Example 1.

[0084] Explanation of the accompanying drawings: 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 material; 200, positive electrode layer; 210, positive electrode current collector; 100, solid electrolyte layer; 300, negative electrode layer; 1, battery pack; 2, upper case; 3, lower case; 4, battery module; 5, all-solid-state battery cell; 51, shell; 52, all-solid-state battery cell; 53, cover plate; 6, electrical device.

[0085] It should be understood that the dimensions of the positive electrode film 20, positive electrode current collector 210, positive electrode active material layer 220, positive electrode layer 200, solid electrolyte layer 100, and negative electrode layer 300 in the various drawings do not represent actual dimensions. The shapes and dimensions of the lithium transition metal oxide 221, positive electrode solid electrolyte 203, and non-carbon conductive material 225 in the positive electrode active material layer 220 of FIG1 do not represent or limit the shapes and dimensions of the actual particles, and the illustrated quantities of the three substances do not represent or limit the actual quantities or ratios. The shapes and dimensions of the lithium transition metal oxide 221, sulfide solid electrolyte 223, and non-carbon conductive material 225 in the positive electrode active material layer 220 of FIG2 do not represent or limit the shapes and dimensions of the actual particles, and the illustrated quantities of the three substances do not represent or limit the actual quantities or ratios. DETAILED DESCRIPTION

[0086] Below, some embodiments of the positive electrode film, positive electrode membrane, solid-state battery (including all-solid-state battery), electrical device and application of the present application are described in detail with appropriate reference to the accompanying drawings. 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 the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0087] " scope " disclosed in the present application can be limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and any end value can be included or not included independently, and can be arbitrarily combined, that is, any lower limit can form a scope with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3,4 and 5 are also listed, then the following scope can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is merely an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to listing the parameter as, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on. For example, when a parameter is expressed as an integer selected from "2-10", this is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0088] In this application, unless otherwise specified, "about" means within a reasonable range above or below the number. The fluctuation range may vary depending on the type and value of the number. For example, a range of ±10%, ±5%, ±2%, ±1%, etc. may be allowed. For example, taking "about 20°C" and its approximate value of ±1°C as an example, approximate values ​​such as 19°C and 19.5°C within the approximate range of "about 20°C" should also be included in the range indicated by "about 20°C".

[0089] In this application, references to "multiple," "multiple," "multiple," "several," and the like, unless otherwise specified, refer to a quantity greater than or equal to two. For example, "one or more" means one or ≥ (greater than or equal to) two. It is understood that references to "any number" of items refer to any suitable combination of multiple items, i.e., any combination of "any number" of items that is not in conflict and that enables the implementation of this application.

[0090] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0091] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment or implementation of the present application. The appearance of such phrases in various locations in the specification does not necessarily refer to the same embodiment, nor does it necessarily refer to independent or alternative embodiments that are mutually exclusive with other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments. References to "implementations" herein have a similar understanding.

[0092] Those skilled in the art will appreciate that, in the methods of each embodiment or embodiment, the order in which each step is written does not mean a strict order of execution and constitutes any limitation to the implementation process, and the detailed order of execution of each step should be determined by its function and possible inherent logic. Unless otherwise specified, all steps of the present application can be performed in sequence, or can be performed randomly, or can preferably be performed in sequence. For example, method M includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, method M may also include step (c), indicating that step (c) can be added to method M in any order, for example, method M may include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0093] In this application, in open technical features or technical solutions described with words such as "contain," "include," and "include," unless otherwise specified, additional members other than the listed members are not excluded, and it can be regarded as providing both closed features or solutions consisting of the listed members and open features or solutions including additional members in addition to the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or not. It can be regarded as providing both the feature or solution of "A consists of a1, a2, and a3" or "A is selected from a1, a2, and a3", and the feature or solution of "A includes not only a1, a2, and a3, but also other members."

[0094] In this application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0095] In this application, "optionally," "optional," and "optional" mean optional, that is, they refer to either option selected from the two parallel options of "yes" or "no." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" is independent. Unless otherwise specified, the descriptions "optionally include," "optionally include," etc. in this application, using "optionally include" as an example, mean "may include or not include."

[0096] In this application, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more relevant listed items, and also include any and all combinations of the relevant listed items, wherein any and all combinations include any two relevant listed items, any more relevant listed items, or a combination of all relevant listed items. For example, "A and / or B" means a group consisting of A, B, and "a combination of A and B." Among them, "including A and / or B" can mean "including A, including B, and including A and B", and can also mean "including A, including B, or including A and B", which can be appropriately understood according to the sentence in which it is used.

[0097] As used herein, "combination thereof", "any combination thereof", "any combination thereof" and the like include all suitable combinations of any two or more of the listed items.

[0098] Herein, the word “suitable” in “suitable combination”, “suitable method”, “any suitable method”, etc., shall be based on the technical solution that can implement the present application.

[0099] Herein, the terms "preferred," "better," "more preferable," "suitable," "comparatively better," and "preferable" are used solely to describe preferred implementations or examples and should not be construed as limiting the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, each "preferred" term is considered independent unless otherwise specified and there are no contradictions or mutual constraints.

[0100] In this application, "further", "further", "particularly", "for example", "such as", "example", "for example", etc. are used for descriptive purposes to indicate differences in content, but should not be understood as limiting the scope of protection of this application.

[0101] In this application, the terms "first," "second," "third," "fourth," and "first conductive material," "second conductive material," and so on are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor as implicitly indicating the importance or quantity of the technical features indicated. Furthermore, "first," "second," "third," and "fourth," etc., serve only as non-exhaustive enumeration and description and should not constitute a closed-ended limitation on quantity.

[0102] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may refer to a relative horizontal positional relationship, or may simply refer to an attachment relationship without limiting the relative horizontal positional relationship.

[0103] 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.

[0104] In this application, when referring to a data range, if the unit is followed only by the right endpoint, it means that the units of the left and right endpoints are the same. For example, "3-5h" or "3-5h" both mean that the units of the left endpoint "3" and the right endpoint "5" are both hours, and both have the same meaning as "3h-5h". Similarly, descriptions of other parameters such as temperature and size are to be understood in the same manner.

[0105] The weight or mass of the relevant components mentioned in the embodiments or examples of the present application can not only refer to the content of each component, but also represent the proportional relationship of weight or mass between each component. Therefore, as long as the content of the relevant components in accordance with the embodiments or examples of the present application is proportionally enlarged or reduced, it is within the scope described in the present application. Further, the mass involved in the embodiments or examples of the present application can be mass units known to the chemical industry such as micrograms (μg), milligrams (mg), grams (g), kilograms (kg). Unless otherwise specified, the mass ratio is equal to the corresponding weight ratio, such as the mass of substance A is m1 and the weight is W1, the mass of substance B is m2 and the weight is W2, then the mass ratio m1 / m2 of the two is numerically equal to the corresponding weight ratio W1 / W2.

[0106] In this application, unless otherwise specified, wt% represents weight percentage by weight and is numerically equivalent to the corresponding mass percentage by mass. In this application, when a weight percentage is represented by "0", it has the same meaning as "0wt%" and can be used interchangeably.

[0107] The units of parameters involved in this application, unless otherwise specified, are nm for nanometers, μm for micrometers, mS / cm for milliSiemens per centimeter, S / cm for Siemens per centimeter, V for volts, mPa·S for millipascals per second, and mg / cm for volts. 2 Expressed in milligrams per square centimeter, g / cm 2 Indicates grams per square centimeter, g / m 2 Indicates grams per square meter, g / cm 3represents grams per cubic centimeter, ℃ represents degrees Celsius, and mA / g represents milliamperes per gram.

[0108] In this application, "greater than or equal to", "greater 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 this application, unless otherwise specified, "greater than or equal to" and "≥" can be regarded as providing two solutions of "greater than" and "equal to". In this application, unless otherwise specified, "less than or equal to" and "≤" can be regarded as providing two solutions of "less than" and "equal to".

[0109] In this application, exemplary descriptions such as "in some embodiments (or examples)" and "in one embodiment (or example)" may include 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.

[0110] In solid-state batteries (such as all-solid-state batteries), the interface contact problem is one of the pain points that limits its performance. Poor interface contact will affect the discharge capacity of the battery and will also deteriorate the battery's rate performance and cycle performance. Taking all-solid-state batteries as an example, the current common practice for all-solid-state batteries is to adopt a composite positive electrode model on the positive electrode side of the all-solid-state battery, and to set positive electrode active materials and solid electrolytes in the positive electrode at the same time. The solid electrolyte is used to enhance the ion 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, and reduce impedance; at the same time, the electronic conductivity of the positive electrode active material itself is used to conduct electrons to improve the battery's cycle stability. However, without adding conductive materials, it is easy to lead to insufficient electronic conductivity and poor overall electrical contact of the positive electrode, affecting the capacity and rate performance of the all-solid-state battery. In practical applications, relying solely on the positive electrode active material to provide electronic conductivity without adding conductive materials can easily lead to unsatisfactory discharge capacity and rate performance of the battery. When the positive electrode of the all-solid-state battery is thicker, the problem is more obvious.

[0111] Oxide positive electrode active materials (such as lithium transition metal oxides) are one of the commonly used positive electrode active materials in traditional lithium-ion secondary batteries and can provide good energy density. Taking lithium transition metal oxides as an example, when lithium transition metal oxides are used in the positive electrode of solid-state batteries (such as all-solid-state batteries), for positive electrodes using lithium transition metal oxides as positive electrode active materials, their electrochemical operating window is usually between 2.8V and 4.8V. For example, the electrochemical operating window of positive electrodes using lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium-rich manganese positive electrode active materials, etc. as positive electrode active materials is usually within the aforementioned range. However, under high voltage, oxide positive electrode active materials (such as lithium transition metal oxides) easily release oxygen and affect the stability of the positive electrode active material, resulting in deterioration of battery cycle performance.

[0112] Sulfide solid electrolytes have excellent ionic conductivity and are a popular solid electrolyte material for solid-state batteries (such as all-solid-state batteries). For cathodes containing sulfide solid electrolytes, when the cathode active material includes an oxide cathode active material (such as a lithium transition metal oxide), the sulfide solid electrolyte is easily oxidized and decomposed at this high voltage due to the relatively high electrochemical operating window, which can easily lead to deterioration of discharge capacity, rate capability, and cycle performance.

[0113] If a composite positive electrode is used on the positive electrode side of a solid-state battery (such as an all-solid-state battery), and a positive electrode active material, a solid electrolyte, and a conductive material are simultaneously provided in the positive electrode sheet, in theory, the solid electrolyte and the conductive material can be used to enhance the ion conductivity and electron conductivity of the positive electrode side, respectively, to promote the charge transfer efficiency between the positive electrode active material and the outside world and the full release of its capacity. It is hoped that the conductive material can be used to enhance the electron conductivity in the composite positive electrode, thereby improving the discharge capacity and rate performance of the battery. It can be inferred that the conductive material will play a vital role in the performance of solid-state batteries (such as all-solid-state batteries).

[0114] 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 an oxide positive electrode active material (such as 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 a solid-state battery (such as an 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 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, it will affect the stability of the electrical contact network of the positive electrode, and further affect the capacity performance and rate performance of a solid-state battery (such as an all-solid-state battery).

[0115] Based on this, the present application provides at least a positive electrode film, a positive electrode film sheet, a solid-state battery (including an all-solid-state battery), an electrical device and an application. The positive electrode film can be used to prepare a solid-state battery (such as an all-solid-state battery) having high discharge capacity, high rate performance and good cycle performance.

[0116] In a first aspect, the present application provides a positive electrode film, which includes a positive electrode active material layer. The positive electrode active material layer includes an oxide positive electrode active material, a positive electrode solid electrolyte and a non-carbon conductive material. The non-carbon conductive material includes at least one of Se单质, Te单质 and Se / Te composite. The chemical formula of the Se / Te composite is Se x Te 1-x , 0 < x < 1. In some embodiments, the oxide positive electrode active material includes a lithium transition metal oxide.

[0117] In some embodiments, a positive electrode film is provided, which includes a positive electrode active material layer 220 (see FIGURE 1 for reference). 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 material 225. The non-carbon conductive material includes at least one of Se单质, Te单质 and Se / Te composite. The chemical formula of the Se / Te composite is Se x Te 1-x , 0 < x < 1.

[0118] By utilizing the synergistic effect between oxide positive electrode active materials (such as lithium transition metal oxides), solid electrolytes and non-carbon conductive materials, 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 solid-state batteries (such as all-solid-state batteries) with high discharge capacity, high rate performance and good cycle performance.

[0119] In this application, unless otherwise specified, the "solid-state battery" provided in this application refers to a battery in which the electrolyte in the battery includes a solid electrolyte; generally, a 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 released back and forth between the positive electrode layer and the negative electrode layer. The solid electrolyte layer plays the role of 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 the positive and negative electrodes from short-circuiting. Therefore, the isolation membrane in the traditional lithium-ion battery can be omitted in the solid-state battery. The solid-state battery uses a non-flammable solid electrolyte to replace the organic electrolyte in the traditional liquid lithium-ion battery, which greatly improves the safety of the battery. In addition to improving safety, solid-state batteries can better adapt to high-energy-density positive and negative electrode materials and reduce the weight of the system, which is conducive to taking into account the improvement of energy density.

[0120] In this application, unless otherwise specified, "solid electrolyte" refers to an electrolyte material or substance that exists in a solid form during the storage and preparation of a solid-state battery and its components, as well as during the operation of the solid-state battery. It is understood that the solid electrolyte exists in a solid form, including but not limited to, at room temperature.

[0121] 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 adopts a solid electrolyte; generally, the 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 released back and forth between the positive electrode layer and the negative electrode layer. The solid electrolyte layer plays the role of 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 the positive and negative electrodes from short-circuiting. Therefore, the isolation membrane used in traditional lithium-ion batteries can be omitted in the all-solid-state battery.

[0122] In this application, unless otherwise specified, an electrode film can be a positive electrode film or a negative electrode film. The electrode film includes an electrode active material. The positive electrode film includes a positive electrode active material. The negative electrode film includes a negative electrode active material. The electrode film can serve as an electrode layer in a solid-state battery.

[0123] In this application, unless otherwise specified, the electrode layer can be a positive electrode layer or a negative electrode layer. The "active material" in the electrode film and the electrode layer refers to a material that can reversibly insert and extract active ions. Unless otherwise specified, the "negative electrode active material" refers to a material used in the negative electrode layer that can reversibly insert and extract active ions; the "positive electrode active material" refers to a material used in the positive electrode layer that can reversibly extract and insert active ions. Taking a all-solid-state battery as a non-limiting example of a solid-state battery, when the all-solid-state battery is charged, the active ions are extracted from the positive electrode and inserted into the negative electrode through the solid electrolyte layer; when the all-solid-state battery is discharged, the active ions are extracted from the negative electrode and inserted into the positive electrode. The active ions are not particularly limited. By way of non-limitation, the active ions can be lithium ions, corresponding to a lithium-ion all-solid-state battery at this time.

[0124] In this application, "electrode active material", "electrode active substance", "active material", and "active substance" have the same meaning and can be used interchangeably; "positive electrode active material" and "positive electrode active substance" have the same meaning and can be used interchangeably; "negative electrode active material" and "negative electrode active substance" have the same meaning and can be used interchangeably. "Positive electrode active material" and "positive electrode active substance" have the same meaning and can be used interchangeably; "negative electrode active material" and "negative electrode active substance" have the same meaning and can be used interchangeably.

[0125] 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. Depending on 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 positive electrode active substances, and the negative electrode active material layer contains negative electrode active substances. In this application, the "electrode active material layer" can also be abbreviated as the "active material layer".

[0126] In this application, unless otherwise specified, the positive electrode layer at least includes a positive electrode active material layer.

[0127] In some embodiments, a positive electrode film is provided, which includes a positive electrode active material layer. The positive electrode active material layer includes an oxide positive electrode active substance, a sulfide solid electrolyte, and a non-carbon conductive substance. The non-carbon conductive substance 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 , 0 < x < 1. In some embodiments, the oxide positive electrode active substance includes a lithium transition metal oxide.

[0128] In some embodiments, a positive electrode film is provided, which includes a positive electrode active material layer 220 (see FIG2 ), wherein 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, wherein the non-carbon conductive material includes at least one of a Se element, a Te element, and a Se / Te complex, wherein the chemical formula of the Se / Te complex is Se x Te 1-x , 0 <x<1。

[0129] In some embodiments, the present application provides a positive electrode film comprising a positive electrode active material layer, the positive electrode active material layer comprising a positive electrode active material, a positive electrode solid electrolyte, and a positive electrode conductive agent;

[0130] The positive electrode active material includes an oxide positive electrode active material (such as 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 elemental substance, Te elemental substance and Se / Te complex, and the chemical formula of the Se / Te complex is Se x Te 1-x , 0 <x<1。

[0131] In this application, unless otherwise specified, "positive electrode film" refers to a membrane that can be used as the positive electrode of a solid-state battery (such as an all-solid-state battery), which at least includes a positive electrode active material layer and usually also includes a positive electrode current collector; "negative electrode film" refers to a membrane that can be used as the negative electrode of a solid-state battery (such as an all-solid-state battery), which at least includes a negative electrode active material layer.

[0132] In this application, unless otherwise specified, "positive electrode solid electrolyte" refers to the solid electrolyte located in the positive electrode membrane. The positive electrode solid electrolyte can enhance the ion conductivity of the positive electrode membrane and reduce the interfacial impedance, thereby promoting the efficient charge transfer between the positive electrode active material and the outside world and fully releasing its capacity.

[0133] In this application, unless otherwise specified, "positive electrode conductive agent" refers to the conductive material located in the positive electrode membrane, which plays the role of conducting electrons in the positive electrode membrane and can improve the electron conduction ability of the positive electrode membrane, thereby improving the discharge capacity and rate performance of the battery.

[0134] In this application, unless otherwise specified, "oxide positive electrode active material" has a well-known meaning in the art, and refers to a positive electrode active material in the form of an oxide. Non-limiting examples of oxide positive electrode active materials include lithium transition metal oxides.

[0135] In this application, unless otherwise specified, “lithium transition metal oxide” has a well-known meaning in the art, and refers to a positive electrode active material containing a transition metal element and a lithium element.

[0136] In this application, unless otherwise specified, "Se element" and "elemental Se" have the same meaning and can be used interchangeably, both representing Se in elemental form. Unless otherwise specified, "Te element" and "elemental Te" have the same meaning and can be used interchangeably, both representing Te in elemental form.

[0137] In this application, unless otherwise specified, "Se / Te composite" refers to a substance composed of Se element and Te element, with the chemical formula Se x Te 1-x (0 < x < 1), and can also be denoted as "selenium tellurium alloy". Generally, the following method can be used to prepare Se / Te composites with specific atomic ratios: 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, then heat at 900 °C to obtain a uniformly mixed melt, and quench the melt in ice water to obtain the Se / Te composite (selenium tellurium alloy).

[0138] 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.

[0139] 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.

[0140] In this application, the "non-carbon conductive substance" in the positive electrode film includes the first conductive substance; in this application, the "first conductive substance" is 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. Without limitation, x can be any one of the following values or a range composed of 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 and Te have relatively high electronic conductivity. The electronic conductivity of Se is about 10 mS / cm, and the electronic conductivity of Te 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 the oxide cathode active material (such as lithium transition metal oxide), selenium (Se) and tellurium (Te) have almost no electrochemical activity and can basically not participate in the electrochemical reaction, and can be basically regarded as not providing capacity. At this time, the capacity is provided by the cathode active material such as the oxide cathode active material (further such as lithium transition metal oxide).

[0141] In the present application, the non-carbon conductive material in the cathode film may include other types of non-carbon conductive materials in addition to the first conductive material, such as non-carbon conductive materials with 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 are non-carbon conductive materials with an electronic conductivity greater than or equal to that of Se under the same test conditions at any temperature from 20 °C to 100 °C or within any temperature range.

[0142] For a solid-state battery (such as a all-solid-state battery) with a lower voltage electrochemical window, Se and Te are used as cathode active materials in the cathode of the solid-state battery (such as a 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 using selenium as the cathode active material (which can be denoted as a lithium-selenium battery) is approximately between 1.0 V and 3.0 V.

[0143] 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 the solid electrolyte and the 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, which 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) and tellurium (Te). Among them, Se and Te both have high electronic conductivity, the electronic conductivity of Se element is about 10mS / cm, and the electronic conductivity of Te element 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 oxide cathode active materials (such as lithium transition metal oxides), selenium (Se) and tellurium (Te) have almost no electrochemical activity and can basically not participate in the electrochemical reaction, thereby maintaining stable electron conduction ability. 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 oxide cathode active materials (such as lithium transition metal oxides), improving the structural stability of the cathode active materials and the electrochemical performance of the battery. Therefore, by introducing non-carbon conductive materials into the cathode film, the resulting solid-state battery (such as an all-solid-state battery) can simultaneously exhibit high discharge capacity, high rate performance, and good cycling performance.

[0144] By utilizing the multiple synergistic effects between oxide positive electrode active materials (such as 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 materials and the outside world and the full release of their capacity, and can be used to prepare solid-state batteries (such as all-solid-state batteries) with high discharge capacity, high rate performance and good cycle performance.

[0145] In this application, unless otherwise specified, a positive electrode active material layer sample can be obtained from a solid-state battery (such as an all-solid-state battery) in the following manner: the battery can be disassembled to obtain an active material layer sample of the electrode plate, and the active material layer can be further analyzed by the following method: the nano-spatial dynamic resolution and layer-by-layer cutting technology of FIB-SEM are used to reconstruct the three-dimensional structure of the sample, and the distribution and proportion of each element are obtained by combining EDS element energy spectrum analysis, and finally the composition and thickness and other parameters of each structural layer of the active material layer are obtained through software quantitative analysis.

[0146] In this application, unless otherwise specified, the type and content of the positive electrode active material (including oxide positive electrode active material, examples of oxide positive electrode active material are lithium transition metal oxides), conductive agent (including non-carbon conductive material), and solid electrolyte in the positive electrode active material layer of a solid-state battery (such as an 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 focused electron beam (FIB) technology, scanning electron microscope (SEM) and elemental analysis technology, for example, it can be obtained by combining continuous sectioning of frozen focused electron beam (FIB), cross-sectional SEM morphology observation, energy dispersive spectroscopy (EDS) elemental spectrum combination and three-dimensional reconstruction analysis software analysis. For example, a cryo-focused ion beam (FIB) can be used to finely slice a sample layer by layer along the transverse direction at different thicknesses (down to the nanometer scale), separating different layers of samples at different thicknesses. Scanning electron microscopy (SEM) testing can also be used to analyze the morphology, structure, and elemental distribution of each cross-section under FIB continuous slicing. Combined with 3D structure reconstruction software, the 3D structure of the sample can be reconstructed, allowing mass and / or volume estimation of different regions of the sample to be tested. As a non-limiting example, the FEI Scios 2HiVac device can be used for testing and analysis of the above parameters.

[0147] Based on any suitable embodiment of the present application, in some embodiments, at at least one temperature between 20°C and 100°C, or at least a portion of the 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 elemental Se. Without limitation, at at least one temperature within a temperature range consisting of any two of the following temperatures, or at least a portion of the 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 elemental Se: 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.

[0148] 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 Se element. Without limitation, the temperature at which the electronic conductivity is tested 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 at which the electronic conductivity is tested 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.

[0149] 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.

[0150] In this application, unless otherwise specified, the electronic conductivity of non-carbon conductive materials may be tested using conventional methods for testing powdered conductive agents, such as a four-probe tester.

[0151] Based on any suitable embodiment of the present application, in some embodiments, the weight percentage of the Te element in the non-carbon conductive material is ≥0 wt %, optionally ≥50 wt %, and further optionally 50 wt % to 100 wt %. Without limitation, the weight percentage of the Te element in the non-carbon conductive material can also be any of the following percentages or a range consisting of any two of the following percentages: 0 wt %, 10 wt %, 20 wt %, 30 wt %, 40 wt %, 50 wt %, 60 wt %, 70 wt %, 80 wt %, 90 wt %, or 100 wt %.

[0152] Te (Te) has a high electronic conductivity (approximately 2000 mS / cm), which is roughly the same order of magnitude as traditional carbon black (for example, carbon black has an electronic conductivity of approximately 10 S / cm to 100 S / cm), providing excellent electronic conductivity. By incorporating a higher proportion of Te into the non-carbon conductive material, the amount of conductive agent and non-carbon conductive material used in the positive electrode film can be reduced, thereby increasing the battery's energy density.

[0153] 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 80wt% to 100wt%, optionally 90wt% to 100wt%, or any of the following percentages or an interval selected from any two of the following percentages: 80wt%, 85wt%, 90wt%, 95wt%, 96wt%, 98wt%, 99wt%, 99.9wt%, 100wt%.

[0154] 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 100wt%, and the non-carbon conductive material is at least one of Se elemental substance, Te elemental substance and Se / Te complex, and the chemical formula of the Se / Te complex is Se x Te 1-x , 0 <x<1。

[0155] By controlling the weight percentage of the first conductive material in the non-carbon conductive material, it is beneficial to better exert the role of the first conductive material in inhibiting the release of oxygen from the oxide positive electrode active material (such as lithium transition metal oxide), which is beneficial to prepare a solid-state battery (such as an all-solid-state battery) with higher discharge capacity, higher rate performance and better cycle performance.

[0156] Based on any suitable embodiment of the present application, in some embodiments, the D of the non-carbon conductive material v 50 is 1nm~20μm, optionally 10nm~5μm, further optionally 10nm~1μm; wherein, D v 50 represents the particle size corresponding to the cumulative volume distribution percentage of the multi-particle mixture reaching 50%. Without limitation, the D of the non-carbon conductive material v 50 can also be any of the following particle sizes or an interval consisting of any two of the following particle sizes: 1nm, 5nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 80nm, 100nm, 0.1μm, 150nm, 0.15μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.8μm, 1μm, 1.1μm, 1.2μm, 1.4μm, 1.5μm, 1.6μm, 1.8μm, 2μm, 2.2μm, 2.4μm, 2.5μm, 2.6μm, 2.8μm, 3μm, 3.5μm, 4μm, 4.5μm, 4.6μm, 4.8μm, 5μm, 6μm, 8μm, 10μm, etc.

[0157] 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 improving the electrical contact between the positive electrode active materials in the electrode membrane, thereby promoting the capacity and rate performance of solid-state batteries (such as all-solid-state batteries). Relatively moderate particle sizes of non-carbon conductive materials are easier to manufacture.

[0158] In the present application, unless otherwise specified, the particle size and particle size distribution of each solid particle in the positive electrode active material layer sample of a solid-state battery (such as an 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 electrode active material, the oxide positive electrode active material in the positive electrode active material (such as lithium transition metal oxide), the non-carbon conductive material and the solid electrolyte: In the present application, unless otherwise specified, FIB-SEM can be combined with EDS testing to obtain a two-dimensional image with different color markings for different components. The positive electrode active material, non-carbon conductive material and solid electrolyte can be distinguished according to the type of component. The particle size and particle size distribution of the positive electrode active material, non-carbon conductive material and solid electrolyte can be analyzed using the software provided by the EDS instrument.

[0159] In the context of this application, the volume cumulative distribution particle size D can be used v N (where N represents any value selected from 0 to 100) is 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%. The particle size is less than or equal to D v The volume percentage of N is N%. v N can be obtained from the volume cumulative distribution curve of the material particle size. If there is no other explanation, the volume cumulative distribution curve starts from zero from the small particle size side. v 50 is used as an example. In this application, if there is no other description, D v 50 refers to the particle size corresponding to when the cumulative volume distribution percentage of the material reaches 50%. This parameter indicates that the particle size of 50% of the material volume is less than or equal to D v 50, and 50% of the volume of the material has a particle size larger than D v 50. Those skilled in the art will understand that v50, and can be measured using instruments and methods known in the art. For example, it can be conveniently measured using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer or the LS-909 laser particle size analyzer (Omega), manufactured by Malvern Instruments Ltd., UK, in accordance with GB / T 19077-2016 Particle Size Distribution by Laser Diffraction Method. Furthermore, for equipment such as the Malvern 2000 laser particle size analyzer, testing can be performed according to the standard procedure GB / T 19077-2016 / ISO 13320:2009.

[0160] 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 can be 0.5 wt % to 5 wt %. Without limitation, the weight percentage of the non-carbon conductive material in the positive electrode active material layer can also be any of the following weight percentages or an interval consisting 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.

[0161] By controlling the weight percentage of non-carbon conductive materials 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, which is more conducive to enabling solid-state batteries (such as all-solid-state batteries) to achieve higher discharge capacity, higher rate performance and better cycle performance.

[0162] Based on any suitable embodiment of the present application, in some embodiments, the positive electrode solid electrolyte includes a sulfide solid electrolyte.

[0163] Without limitation, the weight percentage of the sulfide solid electrolyte in the positive electrode solid electrolyte can be greater than or equal to 50wt% (i.e., ≥50wt%), further can be greater than or equal to 60wt%, further can be greater than or equal to 80wt%, further can be greater than or equal to 90wt%, further can be greater than or equal to 95wt%, and further can be 100wt%. Without limitation, the weight percentage of the sulfide solid electrolyte in the positive electrode solid electrolyte can also be any of the following weight percentages or an interval consisting of any two of the following weight percentages: 50wt%, 55wt%, 60wt%, 65wt%, 70wt%, 72wt%, 74wt%, 75wt%, 76wt%, 78wt%, 80wt%, 82wt%, 84wt%, 85wt%, 86wt%, 88wt%, 90wt%, 92wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%, 100wt%, etc.

[0164] Those skilled in the art will appreciate that if a solvent is required to disperse the sulfide solid electrolyte in a liquid phase, an organic solvent may be used. The organic solvent may include one or two of p-xylene, trimethylbenzene, butyl butyrate, heptane, etc., and may further include p-xylene.

[0165] Sulfide solid electrolytes have very good ion conductivity. By arranging a sulfide solid electrolyte in the positive electrode layer, the charge transfer efficiency between the positive electrode active material and the outside world and the full release of its capacity can be better promoted. Furthermore, selenium (Se) and tellurium (Te) are elements of the same family as sulfur (S), which makes the non-carbon conductive material and the sulfide solid electrolyte have good compatibility. In addition, 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, which is beneficial to reducing the interfacial impedance. In addition, when charged to a high voltage, the oxide positive electrode active material (such as lithium transition metal oxide) may produce oxygen, which in turn attacks the sulfide solid electrolyte, leading to the decomposition of the sulfide solid electrolyte. When a sulfide solid electrolyte is introduced into a solid-state battery positive electrode using an oxide positive electrode active material (such as an all-solid-state battery positive electrode using lithium transition metal oxide) without using a non-carbon conductive material, the oxidative decomposition of the sulfide solid electrolyte easily leads to an increase in interfacial impedance, which in turn affects the discharge capacity and causes the battery's electrochemical performance to be unsatisfactory. The introduction of non-carbon conductive materials can inhibit the oxidative decomposition of sulfide solid electrolytes at high voltages and give full play to the excellent ion-conducting effect of sulfide solid electrolytes. At this time, by utilizing the multiple synergistic effects between the oxide positive electrode active material (such as 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, promoting the charge transfer efficiency between the positive electrode active material and the outside world and the full release of its capacity, and is also more conducive to the preparation of solid-state batteries (such as 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 lithium-ion solid-state batteries (such as lithium-ion all-solid-state batteries) using selenium as the positive electrode active material, the oxidative decomposition problem of sulfide electrolytes is not serious, and a part of the electrolyte is allowed to undergo reversible reduction, thereby providing a part of the capacity; for this type of lithium-selenium battery, carbon conductive materials do not accelerate the oxidative decomposition of sulfide electrolytes, allowing the use of traditional carbon conductive materials as conductive agents in the positive electrode.

[0166] In addition, in traditional lithium-ion batteries, carbon conductive materials are usually used as conductive materials. For the positive electrode whose solid electrolyte includes a sulfide solid electrolyte and whose positive electrode active material includes an oxide positive electrode active material (such as 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 of traditional carbon conductive materials with sulfide solid electrolytes is poor, which leads to the traditional carbon conductive materials easily accelerating the decomposition of sulfide electrolytes, thereby causing an increase in the interface impedance of solid-state batteries (such as all-solid-state batteries) and deterioration of battery cycle performance. There may be two reasons: First, traditional carbon conductive materials usually have a large specific surface area and too high electronic conductivity, which greatly increases the contact area with the sulfide solid electrolyte, resulting in an aggravated accelerated decomposition of the sulfide solid electrolyte; second, the surface of traditional carbon conductive materials generally contains oxygen-containing functional groups, which are easy to react with the sulfide solid electrolyte, thereby causing a large interface impedance. However, if the amount of traditional carbon conductive materials is simply reduced, the stability of the electrical contact network of the positive electrode will be affected, which will in turn affect the capacity and rate performance of the all-solid-state battery.

[0167] In the present application, by introducing a non-carbon conductive material into the positive electrode film, the amount of traditional carbon conductive material in the positive electrode of a solid-state battery (such as an all-solid-state battery) can be replaced or reduced accordingly, and the accelerated decomposition of the sulfide solid electrolyte by the traditional carbon conductive material can be suppressed while achieving good electronic conductivity. By controlling the weight percentage of the non-carbon conductive material in the positive electrode active material layer, the amount of the traditional carbon conductive material can be replaced or reduced accordingly under the amount of conductive material usually required for the positive electrode film, and the solid-state battery (such as an all-solid-state battery) can have better comprehensive performance in terms of discharge capacity, rate performance and cycle performance while achieving a good and stable electrical contact network.

[0168] Furthermore, for a positive electrode membrane comprising an oxide positive electrode active material (such as a lithium transition metal oxide) and a sulfide solid electrolyte, by controlling the weight percentage of the non-carbon conductive material 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 interface impedance while also improving the structural stability of the positive electrode active material, and also inhibiting the oxidative decomposition of the sulfide solid electrolyte at high voltage, which is more conducive to enabling solid-state batteries (such as all-solid-state batteries) to achieve higher discharge capacity, higher rate performance and better cycle performance.

[0169] In some embodiments, the positive electrode conductive agent may or may not include a carbon conductive material.

[0170] In this application, when a carbon conductive agent is included in the positive electrode conductive agent, the corresponding carbon conductive agent may be referred to as a "second conductive material." Without limitation, the second conductive material may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0171] At this time, by introducing a non-carbon conductive material into the positive electrode conductive agent, the amount of traditional carbon conductive material can be replaced or reduced under the amount of conductive material normally required for the positive electrode film, and a high discharge capacity, high rate performance, and good cycle performance can be given to solid-state batteries (such as all-solid-state batteries) while achieving a good and stable electrical contact network. 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.

[0172] Based on any suitable embodiment of the present application, in some embodiments, the weight percentage of the carbon conductive material relative to the non-carbon conductive material is 0-50 wt %, and can be 0-33 wt %. Without limitation, the weight percentage of the carbon conductive material relative to the non-carbon conductive material can also be any of the following weight percentages or a range consisting 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.

[0173] When non-carbon conductive materials partially replace traditional carbon conductive materials, the adverse effects of traditional carbon conductive materials can be better reduced and higher discharge capacity, higher rate performance and better cycle performance can be achieved by controlling the carbon conductive material within the aforementioned lower usage range, such as by controlling one or two parameters 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.

[0174] Based on any suitable embodiment of the present application, in some embodiments, the weight percentage of the carbon conductive material in the positive electrode active material layer is 0-1 wt %, optionally 0-0.5 wt %, and further optionally 0. Without limitation, the weight percentage of the carbon conductive material in the positive electrode active material layer may also be any of the following weight percentages or an interval consisting 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.

[0175] When non-carbon conductive materials completely replace traditional carbon conductive materials, that is, no traditional carbon conductive materials are added to the positive electrode membrane, then, while 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 it is also more conducive to improving the structural stability of the positive electrode active material, thereby achieving higher discharge capacity, higher rate performance and better cycle performance.

[0176] 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.

[0177] The common presence of traditional carbon conductive materials can easily accelerate the oxidative 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 role of non-carbon conductive materials can be exerted.

[0178] 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):

[0179] 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%;

[0180] 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;

[0181] 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.

[0182] Without limitation, the sulfide solid electrolyte may include at least one of a binary sulfide solid system and a ternary sulfide solid system. Without limitation, the binary sulfide solid system may include one or more of Li2S-P2S5, Li2S-SiS2, Li2S-GeS2, and Li2S-B2S3. Without limitation, the ternary sulfide solid state system may include one or more of a thio-germanite sulfide electrolyte, a Li2S-MeS2-P2S5 ternary sulfide electrolyte, a lithium germanium phosphorus sulfur type sulfide electrolyte, a Li2S-P2S5-MS ternary sulfide electrolyte, a Li2S-P2S5-MCl ternary sulfide electrolyte and a thio-LISICON type sulfide electrolyte; wherein Me may include one or more elements of silicon (Si), germanium (Ge), tin (Sn) and aluminum (Al), and may further be selected from one or more elements of Si, Ge, Sn and Al; M may include one or more elements of Ge, Al, Sn, lead (Pb), antimony (Sb), Si and arsenic (As), and may further be selected from one or more elements of Ge, Al, Sn, Pb, Sb, Si and As.

[0183] In the case where the positive electrode of a solid-state battery (such as an all-solid-state battery) includes the aforementioned various sulfide solid electrolytes, the oxidative decomposition of the sulfide solid electrolyte under high voltage can be inhibited by introducing non-carbon conductive substances, thereby improving the discharge capacity, rate performance and cycle performance of the solid-state battery (such as an all-solid-state battery). In addition, the first coulombic efficiency of the solid-state battery (such as an all-solid-state battery) can also be improved.

[0184] Furthermore, the introduction of non-carbon conductive materials can partially or completely replace traditional carbon conductive materials, reduce the accelerated decomposition effect of traditional carbon conductive materials on sulfide solid electrolytes, and better inhibit the decomposition of sulfide solid electrolytes.

[0185] Based on any suitable embodiment of the present application, in some embodiments, D of the sulfide solid electrolyte v 50 is 1nm~20μm, and can be selected as 50nm~5μm; among them, D v 50 represents the particle size corresponding to the cumulative volume distribution percentage of the multi-particle mixture reaching 50%. Without limitation, the D v50 can also be any of the following particle sizes or an interval consisting 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, 1.4μm, 1.5μm, 1.6μm, 1.8μm, 2μm, 2.2μm, 2.4μm, 2.5μm, 2.6μm, 2.8μm, 3μm, 3.5μm, 4μm, 4.5 μm, 4.6μm, 4.8μm, 5μm, 6μm, 8μm, 10μm, 12μm, 12.5μm, 13μm, 14μm, 15μm, 16μm, 18μm, 20μm, etc.

[0186] By controlling the particle size of the sulfide solid electrolyte within the above range, it is beneficial to improve the overall ion conductivity of the sulfide solid electrolyte, provide a better electrical contact network, and take into account the manufacturing cost. The relatively small particle size of the sulfide solid electrolyte is conducive to improving the electrical contact between the positive electrode active materials in the electrode membrane, thereby promoting the capacity and rate performance of solid-state batteries (such as all-solid-state batteries). The relatively moderate particle size of the sulfide solid electrolyte is easier to manufacture.

[0187] 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 can be optionally 5 wt % to 20 wt %. Without limitation, the weight percentage of the sulfide solid electrolyte in the positive electrode active material layer can also be any of the following weight percentages or an interval consisting of any two of the following weight percentages: 0.1wt%, 0.2wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.8wt%, 1wt%, 1.2wt%, 1.5wt%, 1.6wt%, 1.8wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 12wt%, 14wt%, 15wt%, 16wt%, 18wt%, 20wt%, 22wt%, 24wt%, 25wt%, 26wt%, 28wt%, 30wt%, etc.

[0188] The weight percentage of the sulfide solid electrolyte in the positive electrode active material layer can be controlled within the aforementioned range, which is beneficial for providing better overall ion conductivity.

[0189] Without limitation, the oxide positive electrode active material (such as lithium transition metal oxide) in the positive electrode active material may include oxide positive electrode active materials (such as lithium transition metal oxide) that are well known in the art and can be used as positive electrode active materials in solid-state batteries (such as all-solid-state batteries), but is not limited thereto. Examples of oxide positive electrode active materials (such as lithium transition metal oxides) 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 modified compounds thereof. 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 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ) etc. Non-limiting examples of lithium nickel cobalt aluminum oxide may include LiNi 0.80 Co 0.15 Al 0.05 O2.

[0190] In some embodiments, the oxide positive electrode active material contains nickel (Ni) element, further, the oxide positive electrode active material also contains cobalt (Co) element and Q element, Q element can be one or both of manganese (Mn) element and aluminum (Al) element. 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, 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 recorded as Q Ni In some embodiments, Q Ni ≥0.3; optionally, QNi ≥0.5; further optionally, Q Ni ≥0.6; further optionally, Q Ni ≥0.8; further optionally, Q Ni ≥0.9. Without limitation, Q Ni It can also be any of the following values, or ≥ (greater than or equal to) any of the following values ​​and less than 1, or an interval consisting of any two of the following values: 1 / 3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.93, etc. Without limitation, Q Ni You can also select 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.

[0191] In some embodiments, in the oxide positive electrode active material (such as lithium transition metal oxide), the atomic number ratio of nickel element to oxygen element can be recorded as R Ni / O In some embodiments, R Ni / O ≥0.15; optionally, R Ni / O ≥0.25; further optionally, R Ni / O ≥0.3; further optionally, R Ni / O ≥0.4; further optionally, R Ni / O ≥0.45. Without limitation, R Ni / OIt can also be any of the following values, or greater than or equal to any of the following values ​​and less than 0.5, or an interval consisting of any two of the following values: 1 / 6, 0.2, 0.25, 0.3, 1 / 3, 0.35, 0.4, 0.45, 0.46, 0.465, 0.47, etc. In a non-limiting manner, R Ni / O You can also select any of the following ranges: 0.25≤R Ni / O <0.5, 0.25≤R Ni / Oi ≤0.475、0.25≤R Ni / O ≤0.47、0.25≤R Ni / O ≤0.465、0.3≤R Ni / O <0.5, 0.3≤R Ni / O ≤0.475、0.3≤R Ni / O ≤0.47、0.3≤R Ni / O ≤0.465、0.35≤R Ni / O <0.5, 0.35≤R Ni / O ≤0.475、0.35≤R Ni / O ≤0.47、0.35≤R Ni / O ≤0.465、0.4≤R Ni / O <0.5, 0.4≤R Ni / O ≤0.475、0.4≤R Ni / O ≤0.47、0.4≤R Ni / O ≤0.465、0.415≤R Ni / O <0.5, 0.415≤R Ni / O ≤0.475、0.415≤R Ni / O ≤0.47、0.415≤R Ni / O ≤0.465, etc.

[0192] Based on any suitable embodiment of the present application, in some embodiments, the oxide positive electrode active material (such as lithium transition metal oxide) includes 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 manganese-rich positive electrode active material and one or more modified forms of any of the foregoing positive electrode active materials; wherein the chemical formula of the lithium manganese-rich positive electrode active material can be qLi2MnO3-(1-q)LiZO2, Z can include one or more elements of 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 of the following values ​​or an interval consisting of 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, 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.

[0193] Taking an all-solid-state battery as an example, and further taking an all-solid-state battery in which active ions include lithium ions as an example, it is understandable that the all-solid-state battery will be accompanied by the deintercalation and consumption of lithium (Li) during the charge and discharge process, and the content of Li in the positive electrode layer (including the positive electrode film in the context) is different when the battery is discharged to different states. 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 the charge and discharge cycle. The positive electrode active material is applied to the positive electrode layer in the all-solid-state battery system. After the charge and discharge cycle, 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 using atomic molar content, but is not limited to this. 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 is understandable that new materials or new substances obtained by appropriate modification based on the listed positive electrode active materials are also within the scope of positive electrode active materials. The aforementioned appropriate modification refers to an acceptable modification method for the positive electrode active material, and a non-limiting example is coating modification. In the exemplary descriptions of the positive electrode active material in this application, the oxygen (O) content is generally a theoretical value. Lattice oxygen release will cause the atomic molar content of oxygen to change, and the actual O content will fluctuate. The O content can be measured by atomic molar content, but is not limited to this.

[0194] In some embodiments, in addition to oxide positive electrode active materials (such as lithium transition metal oxides), the positive electrode active material may also include other positive electrode active materials that are well known in the art and can be used for solid-state batteries (such as all-solid-state batteries). As a non-limiting example, other positive electrode active materials that can be used for solid-state batteries (such as all-solid-state batteries) may include one or more of the following materials: lithium-containing phosphates with an olivine structure and modified compounds thereof. However, the present application is not limited to these materials, and other existing materials that can be used as positive electrode active materials for solid-state batteries (such as all-solid-state batteries) may 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 an olivine structure may include, but are not limited to, one or more of lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. An example of lithium iron phosphate is LiFePO4 (also referred to as LFP). An example of lithium manganese phosphate is LiMnPO4.

[0195] Without limitation, the weight percentage of the oxide positive electrode active material (such as lithium transition metal oxide) in the positive electrode active material can be greater than or equal to 50wt% (i.e., ≥50wt%), further can be greater than or equal to 60wt%, further can be greater than or equal to 80wt%, further can be greater than or equal to 90wt%, further can be greater than or equal to 95wt%, and further can be 100wt%. Without limitation, the weight percentage of the oxide positive electrode active material (such as lithium transition metal oxide) in the positive electrode active material can also be any of the following weight percentages or an interval consisting of any two of the following weight percentages: 50wt%, 55wt%, 60wt%, 65wt%, 70wt%, 72wt%, 74wt%, 75wt%, 76wt%, 78wt%, 80wt%, 82wt%, 84wt%, 85wt%, 86wt%, 88wt%, 90wt%, 92wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%, 100wt%, etc.

[0196] Non-carbon conductive materials can be introduced into the positive electrode film containing the aforementioned different types of oxide positive electrode active materials (such as lithium transition metal oxides), thereby playing the aforementioned role of improving the discharge capacity, rate performance and cycle performance of solid-state batteries (such as all-solid-state batteries).

[0197] In some embodiments, the D of the positive active material v 50 is 0.1 μm to 20 μm, and can be optionally 1 μm to 10 μm. In a non-limiting manner, the D v 50 can also be any of the following particle sizes or an interval consisting 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 m, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 1 4.5μm, 15μm, 15.5μm, 16μm, 16.5μm, 17μm, 17.5μm, 18μm, 18.5μm, 19μm, 19.5μm, 20μm, etc.

[0198] Based on any suitable embodiment of the present application, in some embodiments, the D v50 is 0.1 μm to 20 μm, and can be 1 μm to 10 μm. In a non-limiting manner, the D v 50 can also be any of the following particle sizes or an interval consisting 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 m, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 1 4.5μm, 15μm, 15.5μm, 16μm, 16.5μm, 17μm, 17.5μm, 18μm, 18.5μm, 19μm, 19.5μm, 20μm, etc.

[0199] By controlling the particle size of the oxide positive electrode active material (such as 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 active material and the sulfide solid electrolyte in the composite positive electrode. The smaller the size of the positive electrode active material, the shorter the transmission channel of active ions (such as lithium ions) inside the positive electrode active material, which is beneficial to the improvement of the discharge capacity of the positive electrode active material itself; the larger the size of the positive electrode active material, the better the interface contact with the sulfide solid electrolyte, and the better the cycle performance of the battery. The relatively moderate size of the positive electrode material can make the battery have both high discharge capacity and excellent cycle performance.

[0200] Based on any suitable embodiment of the present application, in some embodiments, the weight percentage of the oxide positive electrode active material (such as lithium transition metal oxide) in the positive electrode active material layer is 70wt% to 99wt%, and can be 80wt% to 95wt%. Without limitation, the weight percentage of the oxide positive electrode active material (such as lithium transition metal oxide) in the positive electrode active material layer can also be any of the following weight percentages or an interval consisting of any two of the following weight percentages: 70wt%, 72wt%, 74wt%, 75wt%, 76wt%, 78wt%, 80wt%, 82wt%, 84wt%, 85wt%, 86wt%, 88wt%, 90wt%, 92wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%, etc.

[0201] By controlling the weight percentage of the oxide positive electrode active material (such as lithium transition metal oxide) in the positive electrode active material layer within the above range, it is beneficial to achieve both high energy density and cycle stability.

[0202] When the positive electrode film also includes a sulfide solid electrolyte, by controlling the weight percentage of the oxide positive electrode active material (such as lithium transition metal oxide) in the positive electrode active material layer within the above range, it is also beneficial to achieve a balance between high energy density and reducing the oxidative decomposition of the sulfide solid electrolyte.

[0203] In this application, if there is no other explanation or conflict, two or more of the following features related to the technical solution provided by this application 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 v 50. Weight percentage of non-carbon conductive material in the positive electrode active material layer, weight percentage of carbon conductive material relative to non-carbon conductive material, weight percentage of carbon conductive material in the positive electrode active material layer, type of sulfide solid electrolyte, D of sulfide solid electrolyte v 50. The weight percentage of the sulfide solid electrolyte in the positive electrode active material layer, the type of oxide positive electrode active material (such as lithium transition metal oxide), the D v 50. D of oxide positive electrode active material (such as lithium transition metal oxide) v 50. The weight percentage of the oxide positive electrode active material (such as lithium transition metal oxide) in the positive electrode active material layer, the weight percentage of the oxide positive electrode active material (such as lithium transition metal oxide) in the positive electrode active material, etc.

[0204] In a non-limiting manner, the positive electrode film includes a positive electrode current collector and a positive electrode active material layer, wherein the positive electrode active material layer is located on at least one side of the positive electrode current collector.

[0205] 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 30μm to 400μm, and can be optionally 60μm to 130μm, or can be any of the following thicknesses or an interval consisting of any two of the following thicknesses: 30μm, 40μm, 50μm, 60μm, 80μm, 100μm, 120μm, 130μm, 140μm, 150μm, 160μm, 180μm, 200μm, etc. Without limitation, the thickness of the positive electrode active material layer may also be any 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 , 50μm~120μm, 60μm~400μm, 60μm~300μm, 60μm~200μm, 60μm~150μm, 60μm~120μm, 80μm~4 00μm, 80μm~300μm, 80μm~200μm, 80μm~150μm, 80μm~120μm, 100μm~200μm, 120μm~260μm, etc.

[0206] In this application, unless otherwise specified, the "thickness of the positive electrode active material layer" in the positive electrode film refers to the total thickness of the positive electrode film. When the positive electrode active material layer is 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.

[0207] For the positive electrode of a solid-state battery (such as 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 can easily lead to unsatisfactory discharge capacity and rate performance of the battery, and in the case where the positive electrode of the solid-state battery (such as an all-solid-state battery) is thicker, the above-mentioned shortcomings are more obvious. At this time, for a solid-state battery (such as an all-solid-state battery) assembled using the positive electrode film provided by this application, the improvement in discharge capacity and rate performance is more obvious.

[0208] In some embodiments, the positive electrode active material layer optionally includes a binder (which may be referred to as a positive electrode binder). As a non-limiting example, the positive electrode binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin. Typically, the weight percentage of the positive electrode binder in the positive electrode active material layer may be 0 to 10 wt%, further 0 to 8 wt%, further 0.1 wt% to 5 wt%, further 1 wt% to 5 wt%, based on the total weight of the positive electrode active material layer.

[0209] The following are some other descriptions about the positive electrode film.

[0210] In a non-limiting manner, 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 found in the above text.

[0211] 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 found in the above text.

[0212] In some embodiments, referring to FIG. 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 .

[0213] In some embodiments, referring to FIG. 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 .

[0214] Without limitation, the weight percentage of the positive electrode active material in the positive electrode active material layer may be ≥80 wt %, and further may be ≥90 wt %.

[0215] As a non-limiting example, the positive electrode current collector has two surfaces facing away from each other in its thickness direction, and the positive electrode active material layer is disposed on either or both of the two facing surfaces of the positive electrode current collector.

[0216] In some embodiments, the positive electrode film may be in the form of a positive electrode film layer or a positive electrode film sheet.

[0217] The aforementioned positive electrode membrane can be an independent positive electrode membrane sheet, which can be used to assemble a solid-state battery (such as an all-solid-state battery); the aforementioned positive electrode membrane can also be a positive electrode membrane layer present in a composite structure, and the constituent materials of the positive electrode membrane layer can be pressed into a membrane on the surface of the solid electrolyte layer.

[0218] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. In the positive 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 base layer. In the positive electrode current collector, the composite current collector may be obtained by forming a metal material on a polymer material substrate. In the positive electrode current collector, non-limiting examples of the metal material may include at least one of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. In the positive 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.

[0219] The positive electrode film can be prepared by a dry process or a wet process. For example, the film can be formed by dry pressing. Another example is the wet coating process.

[0220] In some embodiments, the positive electrode membrane can be prepared in the following manner: the components for preparing the positive electrode membrane, such as the positive electrode active material, the positive electrode solid electrolyte, the positive electrode conductive agent, the binder (i.e., the positive electrode binder) and any other components are dry-mixed, and then the mixed material is heated, pressurized and kneaded into a mass material, which is hot rolled to form a self-supporting positive electrode sheet, and the self-supporting positive electrode sheet is hot-rolled with the positive electrode collector. The self-supporting positive electrode sheet can be compounded on at least one side (one side or two sides) of the positive electrode collector to obtain a positive electrode membrane. Without limitation, a double planetary mixer can be used for dry mixing. Without limitation, an internal mixer can be used for heating, pressurizing and kneading. Without limitation, the temperature for hot rolling can be 75°C to 85°C, and further such as 78°C, 80°C, 82°C, etc. The method of assembling solid-state batteries (such as all-solid-state batteries) using positive electrode membranes can be suitable for industrial mass production.

[0221] In some embodiments, a positive electrode membrane can be prepared by dispersing the components used to prepare the positive electrode membrane, such as the positive electrode active material, the positive electrode solid electrolyte, the positive electrode conductive agent, the binder (i.e., the positive electrode binder), and any other components, in an organic solvent to form a positive electrode slurry. Furthermore, the positive electrode slurry is coated on at least one side of the positive electrode current collector, and after drying, cold pressing, and other processes, the positive electrode membrane can be obtained. The cold pressing can be performed using a cold rolling mill. The organic solvent in the positive electrode slurry can include one or two of p-xylene, trimethylbenzene, butyl butyrate, heptane, etc., and can further 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 both 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 applying the positive electrode slurry, the coating unit area density based on dry weight (excluding solvent) can be 15 mg / cm 2 ~ 35mg / cm 2 The compaction density of the positive electrode membrane can be 3.0g / cm 3 ~3.6g / cm 3 , optional 3.3g / cm 3 ~3.5g / cm 3 .

[0222] The “compacted density” used in this application has a meaning well known in the art and is one of the reference indicators of material energy density. In this application, unless otherwise specified, the compacted density of an electrode layer refers to the ratio of the mass of the electrode active material layer to its volume. The compacted density of a positive electrode layer, a positive electrode diaphragm or a 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 a negative electrode layer, a negative electrode sheet or a negative electrode diaphragm refers to the ratio of the mass of the negative electrode active material layer to its volume.

[0223] In yet another 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.

[0224] In the second aspect of the present 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 the present application.

[0225] In a third aspect of the present application, a solid-state battery is provided, comprising at least one of the positive electrode film described in the first aspect of the present application and the positive electrode membrane described in the second aspect of the present application.

[0226] In the third aspect of the present application, an all-solid-state battery is also provided, which includes at least one of the positive electrode film described in the first aspect of the present application and the positive electrode membrane described in the second aspect of the present application.

[0227] In a 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.

[0228] In a fifth aspect of the present application, there is provided the use of the positive electrode film described in the first aspect of the present application as a positive electrode membrane in the preparation of a solid-state secondary battery or as a positive electrode membrane layer in a solid-state secondary battery, or the use of the positive electrode membrane described in the second aspect of the present application in the preparation of a solid-state secondary battery. In some embodiments, the solid-state secondary battery is an all-solid-state secondary battery.

[0229] In the fifth aspect of the present application, there is also provided the use of the positive electrode film described in the first aspect of the present 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 use of the positive electrode membrane described in the second aspect of the present application in the preparation of an all-solid-state secondary battery.

[0230] In a sixth aspect of the present application, a non-carbon conductive material is provided as a conductive agent in the positive electrode layer of a solid-state battery. The positive electrode layer of the solid-state battery is 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. In some embodiments, the solid-state battery is an all-solid-state battery.

[0231] In the sixth aspect of the present application, the application of non-carbon conductive materials as conductive agents in the positive electrode layer of an all-solid-state battery is also provided. The positive electrode layer of the all-solid-state battery is 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.

[0232] In some embodiments, the positive electrode film is located in the positive electrode layer of a solid-state battery (such as an all-solid-state secondary battery), and the operating voltage of the solid-state battery (such as an all-solid-state secondary battery) can be greater than 2.5V, further can be greater than or equal to 3.0V, further can be 3.0V~4.8V, further can be 3.0V~4.3V, but is not limited to this.

[0233] The positive electrode layer of a solid-state battery (such as an all-solid-state battery) can be prepared or provided by the aforementioned positive electrode film. In the positive electrode active material layer of the positive electrode film, the positive electrode active material includes an oxide positive electrode active material (such as a lithium transition metal oxide) that can provide a high energy density, and a positive electrode solid electrolyte with a certain ionic conductivity and a non-carbon conductive material with good electronic conductivity are also introduced; within the corresponding electrochemical window, the non-carbon conductive material has a very stable electronic conductivity; the non-carbon conductive material can also absorb oxygen that may be generated by the solidified oxide positive electrode active material (such as a lithium transition metal oxide), which can suppress the The release of oxygen from oxide positive electrode active materials (such as lithium transition metal oxides) can improve the structural stability of the positive electrode active materials, thereby improving battery performance; utilizing the multiple synergistic effects between oxide positive electrode active materials (such as 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 interfacial impedance, and promoting the charge transfer efficiency between the positive electrode active materials and the outside world and the full release of their capacity, which can be used to prepare solid-state batteries (such as all-solid-state batteries) with higher discharge capacity, higher rate performance and good cycle performance.

[0234] 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 material includes an oxide positive electrode active material (such as a lithium transition metal oxide) that can provide a high energy density, includes a sulfide solid electrolyte with excellent ionic conductivity, and also includes a non-carbon conductive material with good electronic conductivity; within the corresponding electrochemical window, the non-carbon conductive material not only has a very stable electronic conductivity, but is also compatible with the sulfide solid electrolyte, has little or no side reaction with the sulfide solid electrolyte, and can reduce the interface impedance; by utilizing the non-carbon conductive material to absorb the solidified oxide positive electrode active material (such as a lithium transition metal oxide), the positive electrode active material can generate a high energy density. Oxygen can not only inhibit the release of oxygen from oxide positive electrode active materials (such as lithium transition metal oxides) and improve the structural stability of the positive electrode active materials, but also inhibit the oxidative decomposition of sulfide solid electrolytes under high voltage and improve battery performance; by utilizing the multiple synergistic effects between oxide positive electrode active materials (such as lithium transition metal oxides), sulfide solid electrolytes and non-carbon conductive materials, 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 materials and the outside world and the full release of their capacity, and can be used to prepare solid-state batteries (such as all-solid-state batteries) with high discharge capacity, high rate performance and good cycle performance.

[0235] In addition, the positive electrode of the solid-state battery (such as an all-solid-state battery) can use less or no traditional carbon conductive materials, which can reduce the accelerated 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 solid-state battery (such as an all-solid-state battery).

[0236] Unless otherwise specified, the solid-state battery provided in this application is a solid-state secondary battery.

[0237] In the present application, the all-solid-state battery includes a solid-state battery cell, and the solid-state battery cell includes the positive electrode film described in the first aspect of the present application.

[0238] Unless otherwise specified, the all-solid-state battery provided in this application is an all-solid-state secondary battery.

[0239] 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.

[0240] In some embodiments, Te powder is used as the positive electrode conductive agent. Since Te powder has higher electronic conductivity, compared with some embodiments in which only Se powder is used as the positive electrode conductive agent, the solid-state battery (such as an all-solid-state battery) prepared using Te powder as the positive electrode conductive agent has better electrochemical performance.

[0241] 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 solid-state battery (such as an 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.

[0242] 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. The discharge capacity, rate performance, and cycle performance of the solid-state battery (such as an 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; and when the Te content is high, the electronic conductivity of the non-carbon conductive material is higher, which can provide more sufficient electron conduction channels. Therefore, the non-carbon conductive material is Se x Te 1-x When the composite is added or Se and Te are mixed, solid-state batteries (such as all-solid-state batteries) can easily obtain better electrochemical performance.

[0243] In some embodiments, the particle size of the non-carbon conductive material is relatively small, and the discharge capacity and cycle stability of the solid-state battery (such as an 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, and thus the electrochemical performance is improved.

[0244] In some embodiments, the weight percentage of the non-carbon conductive material in the positive electrode active material layer is moderate (e.g., 1.8 wt% to 2.2 wt%, further such as 2 wt%), which ensures sufficient electron conduction in the composite positive electrode without affecting ion conduction, resulting in better overall electrochemical performance.

[0245] In some comparative examples, when no non-carbon conductive material is added and only carbon conductive material is used as the positive electrode conductive agent, the performance of the solid-state battery (such as an all-solid-state battery) deteriorates significantly as the amount of carbon conductive material increases. At the same amount of positive electrode conductive agent, the electrochemical performance of solid-state batteries (such as all-solid-state batteries) using non-carbon conductive materials (such as Se) as positive electrode conductive agents is better than the electrochemical performance of solid-state batteries (such as all-solid-state batteries) using only carbon conductive materials (such as Super P) as positive electrode conductive agents.

[0246] In some embodiments, the positive electrode solid electrolyte includes a sulfide solid electrolyte, and a non-carbon conductive material (such as Se) is used as a positive electrode conductive agent, which significantly improves the electrochemical performance of solid-state batteries (such as all-solid-state batteries). It is also confirmed that non-carbon conductive materials (such as Se) can inhibit the decomposition of sulfide solid electrolytes.

[0247] In some embodiments, by adding a small amount of carbon conductive material to a non-carbon conductive material, a solid-state battery (such as an all-solid-state battery) can still maintain good electrochemical performance, which is far better than the electrochemical performance of a solid-state battery (such as an all-solid-state battery) when only carbon conductive material is used as a positive electrode conductor.

[0248] In some embodiments, the positive electrode solid electrolyte includes a sulfide solid electrolyte. When a small amount of carbon conductive material is added to a non-carbon conductive material, the battery performance when carbon nanotubes are used as the carbon conductive material is better than the battery performance when Super P is used. This is because the carbon nanotubes are slender and have a small contact area with the sulfide solid electrolyte. Therefore, the decomposition effect on the sulfide solid electrolyte is smaller than that of Super P.

[0249] In some embodiments, by reducing the particle size of the sulfide solid electrolyte, the ion contact in the composite positive electrode will be improved, and the capacity, rate performance, and cycle performance of the battery will be correspondingly improved.

[0250] In some embodiments, reducing the particle size of the positive electrode active material shortens the diffusion path within the positive electrode, thereby increasing the battery's discharge capacity. In other embodiments, increasing the particle size of the positive electrode active material allows the larger positive electrode material to be better encapsulated by the positive electrode solid electrolyte (e.g., a sulfide solid electrolyte), resulting in better contact with the positive electrode solid electrolyte and improved battery cycle performance.

[0251] In some embodiments, the oxide positive electrode active material (such as 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), an extremely high battery capacity can be obtained while still having good rate performance and cycle performance.

[0252] In some embodiments, the cathode film provided herein has good adaptability to a variety of different oxide cathode active materials (such as lithium transition metal oxides).

[0253] In some embodiments, the positive electrode membrane provided in the present application has good adaptability to a variety of different positive electrode solid electrolytes (such as different sulfide electrolytes), and the assembled solid-state batteries (such as all-solid-state batteries) have excellent electrochemical properties.

[0254] In some embodiments, when a sulfide solid electrolyte with high ionic conductivity is used as the positive electrode solid electrolyte, the electrochemical performance of a solid-state battery (such as an all-solid-state battery) using only a sulfide solid electrolyte as the positive electrode solid electrolyte is better than using only a halide solid electrolyte or a combination of a halide solid electrolyte and a sulfide solid electrolyte.

[0255] In some embodiments, the cathode film is formed by pressing powder onto a solid electrolyte sheet to form a cathode film layer, or by forming a separate cathode film sheet. Solid-state batteries (e.g., all-solid-state batteries) assembled using either method exhibit excellent electrochemical performance. There are no restrictions on the cathode film forming method; all methods have good adaptability.

[0256] In some embodiments, without using a binder, the positive electrode film is pressed on a solid electrolyte sheet using a powder pressing method to form a positive electrode film layer, and the assembled solid-state battery (such as an all-solid-state battery) is very good.

[0257] In this application, the electrochemical performance of a battery, unless otherwise specified, generally includes comprehensive performance in terms of capacity, rate performance and cycle performance.

[0258] A solid-state battery includes at least one solid-state battery cell. A solid-state battery may include one or more solid-state battery cells.

[0259] In this application, unless otherwise specified, a "solid-state battery cell" refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and its components are all solid. In some embodiments, the solid-state battery cell can be an all-solid-state battery cell.

[0260] In this application, unless otherwise specified, an "all-solid-state battery cell" refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and all its components are solid.

[0261] Without limitation, a solid-state battery cell (which may be an all-solid-state battery cell) may include a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, wherein 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 acts as an ion conductor 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 circuits between the positive and negative electrodes.

[0262] Unless otherwise specified, the positive electrode layer in a solid-state battery (such as an all-solid-state battery) includes the positive electrode film described in the first aspect of the present application. It can be composed solely 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 can be combined with other films suitable for the positive electrode to form a positive electrode layer.

[0263] The following is some description about the negative electrode layer.

[0264] The negative electrode layer can be provided by a negative electrode sheet or negative electrode membrane that can be used in solid-state batteries (such as all-solid-state batteries) in the art. Alternatively, the negative electrode layer component materials can be directly pressed onto one side of the solid electrolyte layer to form a negative electrode membrane layer. The negative electrode membrane can be combined with other membranes suitable for the negative electrode to form a negative electrode sheet or negative electrode layer.

[0265] The negative electrode layer can be prepared by a dry process or a wet process. For example, a dry process can be used to form a film by pressing. Another example is a wet process can be used to form a film by coating.

[0266] The negative electrode layer includes a negative electrode active material layer, and the negative electrode active material layer includes a negative electrode active material.

[0267] Without limitation, the weight percentage of the negative electrode active material in the negative electrode active material layer may be ≥80 wt %, and further may be ≥90 wt %.

[0268] In some embodiments, the negative electrode active material is a lithium-indium alloy (InLi alloy).

[0269] In some embodiments, the negative electrode layer is an InLi alloy film.

[0270] In some embodiments, the negative electrode active material may also adopt a negative electrode active material that is well known in the art and can be used for solid-state batteries (such as all-solid-state batteries). As a non-limiting example, the negative electrode active material may include one or more of the following materials: elemental silicon, elemental tin, silicon-carbon negative electrode, silicon monoxide, graphite, and metallic lithium. However, the present application is not limited to these materials or substances, and other traditional materials that can be used as battery negative electrode active materials can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0271] In some embodiments, the negative electrode sheet or negative electrode film may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, the negative electrode active material layer including a negative electrode active material. As a non-limiting example, the negative electrode current collector has two surfaces that face away from each other in the thickness direction of the negative electrode current collector, and the negative electrode active material layer is disposed on either or both of the two facing surfaces of the negative electrode current collector. In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. 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 base layer. In the negative electrode current collector, the composite current collector may be formed by forming a metal material on a polymer material base layer. Non-limiting examples of the metal material in the negative electrode current collector may include one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. 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), and the like.

[0272] In some embodiments, the negative electrode active material layer may optionally include a negative electrode conductive agent. Without limitation, 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. Without limitation, the weight percentage of the negative electrode conductive agent in the negative electrode active material layer may be 0 to 15 wt %, further preferably 0 to 10 wt %, and even further preferably 0 to 5 wt %.

[0273] In some embodiments, the negative electrode active material layer may optionally include a binder (referred to as a negative electrode binder). As non-limiting examples, the negative electrode binder may include, but is not limited to, one or more of styrene-butadiene rubber (SBR), polyacrylic acids (PAAs), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS). Without limitation, the weight percentage of the negative electrode binder in the negative electrode active material layer may be 0-10 wt %, further 0-5 wt %, further 1 wt %-5 wt %, and further optionally 1 wt %-3 wt %.

[0274] In some embodiments, the negative electrode active material layer may optionally include other additives, such as a thickener (e.g., sodium carboxymethyl cellulose (CMC-Na)). The weight percentage of the other additives in the negative electrode active material layer may be 0-15 wt %, further preferably 0-10 wt %, further preferably 0-5 wt %, further preferably 0-3 wt %, and further preferably 0-2 wt %.

[0275] In some embodiments, the negative electrode sheet or negative electrode film can be prepared in the following manner: the components for preparing the negative electrode sheet or negative electrode film, such as the negative electrode active material, the negative electrode conductive agent, the binder (i.e., the negative electrode binder) and any other components are dispersed in a solvent (a non-limiting example of the solvent is N-methylpyrrolidone (NMP)) to form a negative electrode slurry. Further, the negative electrode slurry is coated on at least one side of the surface of the negative electrode collector, and after drying, cold pressing and other processes, the negative electrode sheet or negative electrode film can be obtained. The cold pressing can be performed using a cold rolling mill. The surface of the negative electrode collector coated with the negative electrode slurry can be on a single surface of the negative electrode collector or on both surfaces of the negative electrode collector. The solid content of the negative electrode slurry can be 30wt% to 70wt%, and can optionally be 40wt% to 60wt%. The viscosity of the negative electrode slurry at room temperature can be adjusted to 2000mPa·s to 10000mPa·s, and can be optionally 3000mPa·s to 10000mPa·s. When applying the negative electrode slurry, the coating unit area density based on dry weight (excluding solvent) can be 75g / m 2 ~220g / m 2 The compaction density of the negative electrode sheet or negative electrode membrane can be 1.0g / cm 3 ~2.0g / cm 3 , optional 1.0g / cm 3 ~1.8g / cm 3 .

[0276] The following is some description about the solid electrolyte layer.

[0277] The solid electrolyte layer plays the role of 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 the positive and negative electrodes from short-circuiting.

[0278] The solid electrolyte layer includes a solid electrolyte. The solid electrolyte in the solid electrolyte layer can adopt a solid electrolyte known in the art that can be used for solid-state batteries (such as all-solid-state batteries). As a non-limiting example, the solid electrolyte in the solid electrolyte layer may include one or more of the following materials: a sulfide solid electrolyte, a halide solid electrolyte, an oxide solid electrolyte, a polymer solid electrolyte, etc. The type of sulfide solid electrolyte in the solid electrolyte layer may be the same as or different from the sulfide solid electrolyte in the positive electrode layer (such as the aforementioned positive electrode film).

[0279] As another non-limiting example, the positive electrode solid electrolyte and the solid electrolyte in the solid electrolyte layer may each independently include but are not limited to one or more of an oxide solid electrolyte, a sulfide solid electrolyte and a halide solid electrolyte. In some embodiments, the positive electrode solid electrolyte and the solid electrolyte in the solid electrolyte layer may each independently include but are not limited to one or more of an Argyrodite-type sulfide electrolyte and a halide electrolyte. Among them, non-limiting examples of oxide solid electrolytes may include LISICON-type oxide electrolytes (such as γ-Li3PO4, etc.), NASICON-type oxide electrolytes (such as Li 1+x Al x Ge 2-x (PO4)3,Li 1+x Al x Ti 2-x (PO4)3, etc., 0≤x≤1), Garnet type (such as Li7La3Zr2O 12 etc.), perovskite-type oxide electrolytes (such as Li 3x La 2 / 3-x TiO3, etc., 0≤x≤0.5) etc. Non-limiting examples of sulfide-based solid electrolytes may include Li 10 GeP2S 12 , Li2S-P2S5, Argyrodite type (such as Li6PS5Cl, Li 5.5 PS 5.5 Cl 1.5 Non-limiting examples of the halide-based solid electrolyte may include one or more of Li3InCl6, Li3YCl6, Li3ScCl6, Li3ErCl6, Li2ZrCl6, etc.

[0280] In some embodiments, the solid electrolyte layer may be pressed from a solid electrolyte material into a solid electrolyte membrane.

[0281] In some embodiments, the thickness of the solid electrolyte layer may be 0.1 μm to 1000 μm, and may be optionally 10 μm to 100 μm, 100 μm to 800 μm, 500 μm to 800 μm, or the like.

[0282] In a non-limiting manner, the positive electrode membrane, the solid electrolyte membrane and the negative electrode membrane can be stacked in sequence, the solid electrolyte can be placed between the positive electrode membrane and the negative electrode membrane, and the all-solid-state battery cell can be prepared by hot rolling.

[0283] In some embodiments, the solid-state battery cell comprises a solid-state battery cell. In some embodiments, the solid-state battery cell is an all-solid-state battery cell.

[0284] In some embodiments, an all-solid-state battery cell includes an all-solid-state battery cell.

[0285] In some embodiments, a solid-state battery cell such as (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, an example of which can be seen in FIG5 . Unless otherwise specified, the positive electrode layer 200 includes a positive electrode film 20 .

[0286] In some embodiments, a solid-state battery cell, such as 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. The positive electrode layer 200 includes a positive electrode film 20, which includes a positive electrode current collector 210 and positive electrode active material layers 220 located on both sides of the positive electrode current collector. The positive electrode active material layer 220 is disposed between the positive electrode current collector 210 and the solid electrolyte layer 100. An example of this is shown in FIG6.

[0287] In some embodiments, a solid-state battery such as an all-solid-state battery may include an outer packaging. The outer packaging may be used to encapsulate the above-mentioned solid-state battery cell such as an all-solid-state battery cell.

[0288] In some embodiments, the outer packaging of a solid-state battery such as an all-solid-state battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of a solid-state battery such as an all-solid-state battery may also be a soft package, such as a bag-type soft package. The material of the soft package may be plastic. Further, non-limiting examples of plastic may include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0289] A solid-state battery includes at least one solid-state battery cell. A solid-state battery may include one or more solid-state battery cells.

[0290] The all-solid-state battery includes at least one all-solid-state battery cell. The all-solid-state battery may include one or more all-solid-state battery cells.

[0291] The present application has no particular restrictions on the shape of a solid-state battery cell, such as an all-solid-state battery cell, which can be cylindrical, square, or any other shape. For example, FIG7 shows an all-solid-state battery cell 5 with a square structure as an example.

[0292] In some embodiments, referring to Figure 8, the outer packaging may include a shell 51 and a cover plate 53. The shell 51 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. Solid-state batteries such as (all-solid-state batteries 52) are encapsulated in the receiving cavity. The number of solid-state batteries contained in the solid-state battery cell can be one or more (for example, the number of all-solid-state batteries 52 contained in the all-solid-state battery cell 5 can be one or more), and those skilled in the art can make a choice according to actual needs.

[0293] A solid-state battery such as an all-solid-state battery can be a battery module 4 or a battery pack 1 .

[0294] The battery module includes at least one solid-state battery cell, such as an all-solid-state battery cell. The number of solid-state battery cells, such as an all-solid-state battery cell, contained in the battery module can be one or more, and those skilled in the art can select an appropriate number based on the application and capacity of the battery module.

[0295] Figure 9 shows an example battery module 4. Referring to Figure 9 , in battery module 4, multiple solid-state battery cells, such as (all-solid-state battery cells 5), can be arranged sequentially along the length of battery module 4. Of course, they can also be arranged in any other manner. Furthermore, these multiple solid-state battery cells, such as (all-solid-state battery cells 5), can be secured using fasteners.

[0296] Optionally, the battery module 4 may further include a housing having a housing space, in which a plurality of solid-state battery cells, such as (all-solid-state battery cells 5 ), are housed.

[0297] In some embodiments, the battery modules may be assembled into a battery pack. The battery pack may contain one or more battery modules. Those skilled in the art may select an appropriate number based on the application and capacity of the battery pack.

[0298] Figures 10 and 11 illustrate an exemplary battery pack 1. Referring to Figures 10 and 11 , the battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box comprises an upper case 2 and a lower case 3. The upper case 2 can be positioned over the lower case 3 to form an enclosed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0299] In some embodiments, the electrical device includes a solid-state battery according to any embodiment of the present application, such as an all-solid-state battery.

[0300] Without limitation, solid-state batteries such as (all-solid-state batteries) can be used as power sources for electrical devices, and can also be used as energy storage units for electrical devices. Electrical devices may include mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc., but are not limited thereto. Among them, mobile devices may be, for example, mobile phones, laptops, etc.; electric vehicles may 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 thereto. The electrical device can also be used in military equipment, aerospace and other fields, and can also be used in energy storage power supply systems such as hydropower, thermal power, wind power and solar power stations.

[0301] As an electrical device, a solid-state battery such as (all-solid-state battery) can be selected according to its usage requirements.

[0302] Figure 12 shows an example of an electric device 6. This device is a pure electric vehicle, hybrid electric vehicle, or plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of a solid-state battery, such as an all-solid-state battery, a battery pack or battery module can be used.

[0303] As another example, the device may be a mobile phone, a tablet computer, a laptop computer, etc. Such a device is usually required to be lightweight and thin, and may use a solid-state battery such as an all-solid-state battery as a power source.

[0304] 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 limiting the present application. If the techniques or conditions are not specified in the embodiments, they shall be carried out in accordance with the description above, or in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. The reagents or instruments used, for which the manufacturer is not specified, are conventional products that can be obtained commercially, or can be synthesized in a conventional manner from commercially available products. For example, the Se / Te complex involved is prepared by the following method: Se powder and Te powder are weighed in a stoichiometric ratio, vacuum-sealed in a quartz tube, and the vacuum degree is about 10 -5Torr, and then heated at 900 ° C to obtain a uniformly mixed melt, and the melt was quenched in ice water to obtain a Se / Te complex (selenium tellurium alloy) with a specific atomic ratio.

[0305] Unless otherwise specified, in the following examples and comparative examples, raw materials with the same chemical formula are from the same synthesis batch or the same product number, or are prepared according to the same stoichiometric ratio and in accordance with the same method.

[0306] In the following examples, room temperature refers to 20°C to 30°C.

[0307] D v 50 tests:

[0308] In the following examples and comparative examples, the D of the positive electrode active material, the sulfide solid electrolyte and the non-carbon conductive material is v 50 was tested and confirmed using the following method: Equipment model: Malvern 2000 (MasterSizer 2000) laser particle size analyzer, reference standard process: GB / T19077-2016 / ISO 13320:2009, detailed test process: Take an appropriate amount of the sample to be tested (the sample concentration is sufficient to ensure 8%-12% (w / v) light shielding), add 20mL of solvent (such as p-xylene, deionized water), and simultaneously ultraviolet for 5 minutes (53KHz / 120W) to ensure that the sample is completely dispersed. After that, the sample is measured according to the GB / T19077-2016 / ISO 13320:2009 standard. It will be understood by those skilled in the art that when testing sulfide solid electrolytes, if a solvent is involved, unless otherwise specified, reference can be made to the organic solvent of the aforementioned positive electrode slurry, such as p-xylene.

[0309] It should be noted that in the following embodiments and examples, an all-solid-state battery is used as a non-limiting example of a solid-state battery, and a lithium transition metal oxide is used as a non-limiting example of an oxide positive electrode active material.

[0310] Example 1.

[0311] (1) Preparation of positive electrode membrane (as positive electrode sheet):

[0312] 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 1μm), Se powder (D v50 is approximately 50nm), and the binder polytetrafluoroethylene (PTFE) are weighed in a mass ratio of 85:12:2:1, and the mixed powders are then heated, pressurized and kneaded into agglomerated materials in an internal mixer. The materials are then hot-rolled at 80°C to form a self-supporting positive electrode sheet, and finally hot-rolled with a current collector aluminum (Al) foil to obtain a positive electrode sheet. The formed positive electrode active material layer is located on a single side of the positive electrode membrane. The thickness of the aluminum foil is about 12μm, and the thickness of the positive electrode membrane is 100μm.

[0313] (2) Solid electrolyte membrane (as solid electrolyte layer)

[0314] 100 mg of sulfide solid electrolyte Li6PS5Cl was weighed, added to a battery mold, and pressed to obtain an electrolyte sheet with a thickness of 600 μm.

[0315] (3) Negative electrode membrane (as negative electrode)

[0316] InLi alloy film was selected as the negative electrode membrane.

[0317] (4) Assembling all-solid-state batteries

[0318] The positive electrode membrane is stacked on one side of the solid electrolyte sheet, and the InLi alloy membrane is stacked on the other side as the negative electrode membrane, and pressurized at 360MPa to assemble into an all-solid-state battery.

[0319] Examples 2 to 23 use the same method as Example 1 to prepare all-solid-state batteries. The differences can be found in Tables 1 to 3. One or more of the following parameters are different: the composition of the positive electrode conductive agent (including the type of non-carbon conductive material, the D v 50. Weight percentage of non-carbon conductive material in the positive electrode active material layer, weight percentage of carbon conductive material relative to non-carbon conductive material, weight percentage of carbon conductive material in the positive electrode active material layer, and type of carbon conductive material), composition of the positive electrode solid electrolyte (including type of sulfide solid electrolyte, 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 lithium transition metal oxide in the positive electrode active material layer) and the type of positive electrode film (positive electrode film layer or positive electrode film sheet).

[0320] Example 24. Positive electrode film form

[0321] LiNi 0.83 Co 0.12 Mn 0.05 O2 positive electrode active material (Dv 50 is 4 μm), Li6PS5Cl sulfide solid electrolyte (D v 50 for 1 μm) and Se powder (D v 50 (approximately 50 nm) were uniformly mixed in a mass ratio of 85:12:2 to obtain a composite cathode powder. When assembling an all-solid-state battery, the composite cathode powder was sprinkled on one side of the solid electrolyte sheet and pressurized to obtain a cathode film layer. An InLi alloy was then placed on the other side of the solid electrolyte sheet and pressurized at 360 MPa to obtain an all-solid-state battery. The remaining testing methods were the same as in Example 1.

[0322] Comparative Examples 1 to 4 adopt substantially the same method as Example 1, except that the non-carbon conductive material is replaced with carbon conductive material Super P with different contents.

[0323] Comparative Example 5: A method substantially the same as that of Example 1 was used, except that the non-carbon conductive material was replaced with carbon nanotubes with different contents of carbon conductive material.

[0324] Table 1.

[0325] Table 2.

[0326] Table 3.

[0327] In Tables 1, 2, and 3, D v Values ​​greater than or equal to 50 are rounded up and entered; for values ​​expressed as approximate numbers, "about 50 nm" means 50±1 nm, and "about 100 nm" means 100±2 nm; for values ​​not expressed as approximate numbers, the deviation of the value in μm is within the range of ±0.2 μm.

[0328] Performance testing and analysis:

[0329] The electrochemical performance of the positive electrode and the corresponding all-solid-state battery was tested using a solid-state mold battery, and the battery test window was 2.8V to 4.3V (relative to lithium potential).

[0330] 1. First discharge capacity

[0331] The test process is as follows: the assembled all-solid-state battery is charged to 3.68V (4.3V vs. lithium) at a current density of 0.1C, allowed to rest for 10 minutes, and then discharged to 2.18V (2.8V vs. lithium) at a current density of 0.1C to obtain the battery's initial discharge capacity. The battery is tested at 25±3°C, where 1C = 200mA / g.

[0332] 2. First Coulombic efficiency

[0333] The first coulombic efficiency of the battery can be obtained by dividing the first discharge capacity obtained by the first charge capacity tested at 0.1C.

[0334] 3. Rate performance

[0335] The test process is as follows: the charge rate of the all-solid-state battery is fixed at 0.1C, and then discharged at the rates of 0.1C, 0.33C, 1C, 2C, and 3C, respectively. Each rate is cycled 3 times. The battery voltage test window is 2.8~4.3V vs.Li + / Li, the battery was tested at 25±3°C, where 1C=200mA / g.

[0336] 4. Cycle performance:

[0337] The test process is as follows: the assembled all-solid-state battery is first activated by charging and discharging at 0.1C for 3 cycles, and then the battery is charged and discharged for a long cycle test at 0.33C for 200 cycles, and the battery's cycle capacity retention rate is calculated. The battery's voltage test window is 2.8~4.3Vvs.Li + / Li (for lithium potential, active ions are Li + ) Batteries were tested at 25±3°C, with 1C = 200 mA / g. For test results, see "200-cycle capacity retention, 0.33C" in Table 4.

[0338] Test analysis results:

[0339] The test results of the electrochemical performance of the all-solid-state batteries of each embodiment and each comparative example can be found in Table 4.

[0340] The comparison of the initial charge and discharge curves of Comparative Example 1 and Example 1 can be seen in Figure 13. It can be seen that by replacing the traditional Super P carbon conductive agent with Se powder, the decomposition of the sulfide electrolyte is suppressed, and the initial discharge capacity, coulombic efficiency, cycle performance, and rate performance of the all-solid-state battery are significantly improved.

[0341] Comparative Examples 1-5 all use traditional carbon conductive materials as positive electrode conductive agents. Compared with Examples 1 to 24, the first discharge capacity, coulombic efficiency, cycle performance and rate performance of the all-solid-state batteries in Comparative Examples 1-5 are significantly worse.

[0342] In Example 2, Te powder with high electronic conductivity is used as the positive electrode conductive agent, and the assembled all-solid-state battery has good electrochemical performance;

[0343] The non-carbon conductive materials of Examples 3 to 6 contain both Se and Te elements, and the discharge capacity, rate performance, and cycle performance of the all-solid-state battery are significantly improved compared to Comparative Example 1. Due to the synergistic effect between Se and Te, Se is more likely to combine with peroxide ions to form SeO3 2- , which is more conducive to inhibiting the decomposition of sulfide electrolytes; Te elements can give non-carbon conductive materials higher electronic conductivity and provide more sufficient electronic conduction channels. At this time, the non-carbon conductive material is Se x Te 1-x When Se and Te are mixed and added, the all-solid-state battery has very good electrochemical performance. x Te 1-x Se and Te in the complex are combined at the atomic scale, and the combined effect of the two elements is very excellent.

[0344] In Examples 14-15, a small amount of carbon conductive material (second conductive material) was added to the non-carbon conductive material. The all-solid-state batteries still maintained excellent electrochemical performance, far exceeding that of an all-solid-state battery using only carbon conductive material as the positive electrode conductor (e.g., Comparative Example 5). Furthermore, when using the second conductive material, the carbon nanotubes are elongated, resulting in a smaller contact area with the sulfide solid electrolyte. Using carbon nanotubes as the second conductive material helps reduce the decomposition of the sulfide solid electrolyte.

[0345] The positive electrode film in Example 24 does not contain a binder, and the assembled all-solid-state battery is very good.

[0346] Table 4.

[0347] The description of each embodiment and example above tends to emphasize the differences between each embodiment and example, and the same or similar aspects can be referenced to each other. For the sake of brevity, this article will not go into details. The technical features of the embodiments and examples described above can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments and examples are 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 embodiments and examples. The above embodiments and examples are only examples. Within the scope of the technical solution of this application, embodiments with substantially the same composition as the technical idea and the same effect are included in the technical scope of this application. The above embodiments and examples only express several embodiments of the present application, and their descriptions are relatively detailed, but they cannot be understood as limiting the scope of the patent. In addition, without departing from the scope of the subject matter of this application, various modifications that can be thought of by those skilled in the art to the embodiments or examples, and other methods of combining some of the constituent elements in the embodiments or examples are also included in the scope of this application.

Claims

1. A positive electrode film, which comprises a positive electrode active material layer, and the positive electrode active material layer comprises a positive electrode active substance, a positive electrode solid electrolyte and a positive electrode conductive agent; Among them, The positive electrode active material includes an oxide positive electrode active material, 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; Optionally, the oxide positive electrode active substance comprises a lithium transition metal oxide.

2. The positive electrode film according to claim 1, wherein At at least one temperature or at least a part of the 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 element. Optionally, at any temperature or 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 element.

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

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

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

6. The positive electrode film according to any one of claims 1 to 5, wherein, 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, wherein, 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 is 10 nm to 1 μm.

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

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

11. The positive electrode film according to any one of claims 1 to 10, wherein, The positive electrode solid electrolyte comprises a sulfide solid electrolyte.

12. The positive electrode film according to any one of claims 1 to 11, wherein, 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% to 50 wt%; The weight percentage of the carbon conductive substance in the positive electrode active material layer is 0 wt% to 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, wherein, 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% to 33 wt%; The weight percentage of the carbon conductive substance in the positive electrode active material layer is 0 wt% to 0.5 wt%.

14. The positive electrode film according to any one of claims 11 to 13, wherein, The sulfide solid electrolyte includes at least one of a binary sulfide solid state system and a ternary sulfide solid state 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 state 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, wherein, The D of the sulfide solid electrolyte 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%.

17. The positive electrode film according to claim 16, wherein, 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, wherein, The weight percentage of the sulfide solid electrolyte in the positive electrode active material layer is 0.1 wt% to 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% to 20 wt%.

20. The positive electrode film according to any one of claims 1 to 19, wherein, 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 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.

21. The positive electrode film according to any one of claims 1 to 20, wherein, 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, wherein, 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, wherein, The weight percentage of the lithium transition metal oxide in the positive electrode active material layer is 70 wt% to 99 wt%.

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

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

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

27. The positive electrode film according to any one of claims 1 to 26, wherein 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, which 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 film sheet, 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, 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 solid-state battery, which includes at least one of the positive electrode films according to any one of claims 1 to 27 and the positive electrode film sheet according to claim 29.

31. An all-solid-state battery, which includes at least one of the positive electrode films according to any one of claims 1 to 27 and the positive electrode film sheet according to claim 29.

32. An electrical device, which includes at least one of the solid-state battery according to claim 30 and the all-solid-state battery according to claim 31.

33. Use of the positive electrode film according to any one of claims 1 to 27 as a positive electrode film in the preparation of an all-solid-state secondary battery or as a positive electrode film layer in a solid-state secondary battery, or use of the positive electrode film according to claim 29 in the preparation of a solid-state secondary battery; Optionally, the solid-state secondary battery is an all-solid-state secondary battery.

34. Application of a non-carbon conductive material as a conductive agent in the positive electrode layer of a solid-state battery, wherein, The positive electrode layer of the solid-state battery comprises 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; Optionally, the solid-state battery is an all-solid-state battery.

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