Solid-state battery and preparation method therefor, and electrical device

Abstract

The present application relates to a solid-state battery and a preparation method therefor, and an electrical device. The solid-state battery comprises a solid electrolyte layer, and a positive electrode layer and a negative electrode layer which are located on two sides of the solid electrolyte layer; an interface functional layer is provided between the solid electrolyte layer and at least one of the electrode layers; the interface functional layer between the positive electrode layer and the solid electrolyte layer is a positive electrode interface functional layer, and the interface functional layer between the negative electrode layer and the solid electrolyte layer is a negative electrode interface functional layer; the mass percentages of organic components in the positive electrode interface functional layer, the negative electrode interface functional layer, a positive electrode active material layer in the positive electrode layer, a negative electrode active material layer in the negative electrode layer, and the solid electrolyte layer are respectively denoted as fm1, fm2, fmP, fmN, and fmE; when the positive electrode interface functional layer is present, fm1 is less than at least one of fmP and fmE; when the negative electrode interface functional layer is present, fm2 is less than at least one of fmN and fmE.

Description

Solid-state batteries, their fabrication methods, and electrical devices

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. CN2024109778197, filed on July 19, 2024, entitled "Solid-state battery and method for preparation thereof and electrical device thereof", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of solid-state battery technology, and further to solid-state batteries, their preparation methods, and electrical devices. Background Technology

[0004] The statements herein are provided only as background information in connection with this application and do not necessarily constitute prior art.

[0005] Solid-state batteries use a non-flammable solid electrolyte to replace the organic electrolyte in traditional liquid secondary batteries, significantly improving battery safety and are considered the next generation of batteries closest to industrialization. However, poor interface compatibility in solid-state batteries leads to less than ideal battery cycle performance. Summary of the Invention

[0006] According to various embodiments and examples of this application, this application provides a solid-state battery, a method for preparing the same, and an electrical device thereof. This solid-state battery exhibits improved cycle performance.

[0007] In some embodiments of the first aspect of this application, a solid-state battery is provided, which includes a solid electrolyte layer and two electrode layers located on both sides of the solid electrolyte layer, wherein one electrode layer is a positive electrode layer and the other electrode layer is a negative electrode layer; the positive electrode layer includes a positive electrode active material layer and the negative electrode layer includes a negative electrode active material layer;

[0008] An interface functional layer is provided between the solid electrolyte layer and at least one of the electrode layers; the interface functional layer located between the positive electrode layer and the solid electrolyte layer is referred to as the positive electrode interface functional layer, and the interface functional layer located between the negative electrode layer and the solid electrolyte layer is referred to as the negative electrode interface functional layer.

[0009] The mass percentage of the organic component in the positive electrode interface functional layer is denoted as f. m1 The mass percentage of the organic components in the negative electrode interface functional layer is denoted as f. m2 The mass percentage of the organic component in the positive electrode active material layer is denoted as f. mP The mass percentage of the organic component in the negative electrode active material layer is denoted as f. mN The mass percentage of the organic components in the solid electrolyte layer is denoted as f.mE ;

[0010] in,

[0011] When the positive electrode interface functional layer exists, f m1 Less than f mP and f mE At least one of them;

[0012] When the negative electrode interface functional layer exists, f m2 Less than f mN and f mE At least one of them.

[0013] This solid-state battery incorporates an interfacial functional layer between a solid electrolyte layer and at least one electrode layer. The organic component content in this interfacial functional layer is lower than that in at least one of the solid electrolyte layer and adjacent electrode active material layers. This allows the interfacial functional layer to exhibit better charge transfer performance, improved ion and electron conduction, and higher overall conductivity. It also enhances the interfacial compatibility between the electrode layer and the solid electrolyte layer, reduces interfacial impedance, and thus improves the battery's electrochemical performance, including cycle performance. Furthermore, it also contributes to improved discharge capacity and rate performance.

[0014] In some embodiments, the organic component includes one or more of organic binders and organic dispersants;

[0015] The organic binder includes one or more of polyvinylidene fluoride, styrene-butadiene rubber latex, carboxymethyl cellulose, sodium carboxymethyl cellulose, sodium alginate, polyvinyl alcohol, polymethyl methacrylate, hydrogenated nitrile rubber, polytetrafluoroethylene, and polyacrylic acid.

[0016] The organic dispersant includes one or more of cationic wetting and dispersing agents, anionic wetting and dispersing agents, and amphoteric wetting and dispersing agents; the cationic wetting and dispersing agent includes one or more of amine salts, quaternary ammonium salts, and pyridinium salts; the anionic wetting and dispersing agent includes one or more of fatty acid salts, sulfate ester salts, and sulfonates; and the amphoteric wetting and dispersing agent includes phosphate ester salt type polymers.

[0017] Organic components such as organic binders and organic dispersants can be set in the electrode active material layer adjacent to the interface functional layer, and the content of these organic components can be controlled to be lower in the interface functional layer, thereby giving the interface functional layer better ion conduction and electron conduction properties.

[0018] By selecting the aforementioned organic components and setting a content difference between adjacent electrode layers and interface functional layers, it is possible to balance good interfacial contact and structural stability within the electrode layers with high electrical conductivity in the interface functional layers.

[0019] In some implementations, the thickness of any interface functional layer is less than or equal to 50 μm.

[0020] In some implementations, the thickness of any interface functional layer is 1 μm to 50 μm.

[0021] By controlling the thickness of the interface functional layer within the aforementioned range, it is beneficial to improve interface compatibility, reduce interface impedance, and achieve better interface adhesion, which in turn helps solid-state batteries to have better structural stability.

[0022] In some embodiments, the solid-state battery satisfies one or both of the following characteristics:

[0023] The positive electrode interface functional layer exists, f m1 <f mP And f m1 <f mE ;

[0024] The negative electrode interface functional layer exists, f m2 <f mN And f m2 <f mE .

[0025] In some embodiments, the conductivity of the positive electrode interface functional layer is denoted as σ1; the conductivity of the negative electrode interface functional layer is denoted as σ2; ​​and the conductivity of the positive electrode active material layer is denoted as σ P The conductivity of the negative electrode active material layer is denoted as σ. N The conductivity of the solid electrolyte layer is denoted as σ. E ;

[0026] The solid-state battery satisfies one or more of the following characteristics:

[0027] The positive electrode interface functional layer exists, and σ1 is greater than σ. P and σ E At least one of them; alternatively, when σ1>σ P time f m1 <f mP When σ1>σ E time f m1 <f mE ;

[0028] The negative electrode interface functional layer exists, and σ2 is greater than σ. N and σ E At least one of them; alternatively, when σ2>σ N time f m2 <f mN When σ² > σ E time f m2 <f mE .

[0029] In some embodiments, the solid-state battery satisfies one or more of the following characteristics:

[0030] The positive electrode interface functional layer exists, and σ1>σ P And f m1 <f mP Or, σ1>σ E And f m1 <f mE ;

[0031] The negative electrode interface functional layer exists, and σ2>σ N And f m2 <f mN Or, σ²>σ E And f m2 <f mE ;

[0032] The positive electrode interface functional layer exists, f m1 <f mP And f m1 <f mE , σ1>σ P And σ1>σ E ;

[0033] The negative electrode interface functional layer exists, f m2 <f mN And f m2 <f mE , σ2>σ N And σ² > σ E .

[0034] By controlling the content of organic components in the positive electrode interface functional layer to be lower than that in both the positive electrode active material layer and the solid electrolyte layer, the positive electrode interface functional layer can provide better ion conduction and electronic conduction properties, which is more conducive to reducing interface impedance.

[0035] When a positive electrode interface functional layer is present, its conductivity can be higher than that of at least one of the positive electrode active material layer and the solid electrolyte layer. Furthermore, by controlling the content of organic components in the positive electrode interface functional layer to be lower than that in both the positive electrode active material layer and the solid electrolyte layer, the overall conductivity of the positive electrode interface functional layer can be made higher than that of both the positive electrode layer and the solid electrolyte layer.

[0036] When the conductivity σ1 of the positive electrode interface functional layer is higher than the conductivity σ of the positive electrode active material layer P At that time, the mass percentage f of the organic components in the positive electrode interface functional layer can be set. m1 The mass percentage f of organic components in the positive electrode active material layer is lower than that of the positive electrode active material layer. mP .

[0037] When the conductivity σ1 of the positive electrode interface functional layer is higher than the conductivity σ of the solid electrolyte layer E At that time, the mass percentage f of the organic components in the positive electrode interface functional layer can be set. m1 The mass percentage f of organic components in the solid electrolyte layer mE .

[0038] When the content of organic components in the positive electrode interface functional layer is lower than that in both the positive electrode active material layer and the solid electrolyte layer, the positive electrode interface functional layer can provide better ion conduction and electronic conduction properties, which is more conducive to reducing interface impedance.

[0039] When a negative electrode interface functional layer is present, its conductivity can be higher than that of at least one of the negative electrode active material layer and the solid electrolyte layer. Furthermore, by controlling the content of organic components in the negative electrode interface functional layer to be lower than both the negative electrode active material layer and the solid electrolyte layer, the overall conductivity of the negative electrode interface functional layer can be made higher than that of both the negative electrode layer and the solid electrolyte layer.

[0040] When the conductivity σ2 of the negative electrode interface functional layer is higher than the conductivity σ of the negative electrode active material layer N At that time, the mass percentage f of the organic components in the negative electrode interface functional layer can be set. m2 The mass percentage f of organic components in the negative electrode active material layer is lower than that of the negative electrode active material layer. mN .

[0041] When the conductivity σ2 of the negative electrode interface functional layer is higher than the conductivity σ of the solid electrolyte layer E At that time, the mass percentage f of the organic components in the negative electrode interface functional layer can be set. m2 The mass percentage f of organic components in the solid electrolyte layer mE .

[0042] In some implementations, the interface functional layer satisfies one or both of the following characteristics:

[0043] At least a portion of the interface functional layer is an extension region of the adjacent electrode active material layer;

[0044] At least a portion of the interface functional layer is an extension region of the solid electrolyte layer.

[0045] When at least a portion of the interface functional layer is an extension region of the adjacent electrode active material layer, the interface functional layer provides better charge transfer, better ion conduction and electronic conduction, and has better interfacial adhesion and lower interfacial impedance with the adjacent electrode layer, which can significantly improve the cycle performance of the battery.

[0046] When at least a portion of the interfacial functional layer is an extension of the solid electrolyte layer, the interfacial functional layer provides better charge transfer, better ion conduction and electronic conduction, and has better interfacial adhesion and lower interfacial impedance with the solid electrolyte layer, which can significantly improve the cycle performance of the battery.

[0047] When at least a portion of the interface functional layer is an extension of the adjacent electrode active material layer and at least a portion of the interface functional layer is an extension of the solid electrolyte layer, the interface adhesion is better, the interface impedance is lower, and the improvement effect on battery performance is more significant, including at least the improvement on battery cycle performance.

[0048] In some embodiments, the interface functional layer includes an interface layer active material of the same type as the electrode active material in the adjacent electrode layer, and also includes an interface layer electrolyte material of the same type as the solid electrolyte material in the solid electrolyte layer.

[0049] By setting the same type of electrode active material in the interface functional layer as in the electrode active material layer and the same type of solid electrolyte material in the solid electrolyte layer, the compatibility between the interface functional layer and the electrode layer and the solid electrolyte layer can be better improved, and the interfacial impedance between the electrode layer and the solid electrolyte layer can be reduced.

[0050] In some implementations, the interface functional layer has overlapping interfaces.

[0051] The interfacial functional layer has the characteristic of interfacial contact area, which can improve the interfacial connection and adhesion, and reduce the interfacial impedance. This helps to better layer-to-layer composite between the electrode layer and the solid electrolyte layer, and thus can better reduce the interfacial impedance between the electrode layer and the solid electrolyte layer.

[0052] In some implementations, each interface functional layer independently includes a first sublayer and a second sublayer, with the second sublayer located between the first sublayer and the solid electrolyte layer;

[0053] The first sublayer and the adjacent electrode layer contain the same type of electrode active material;

[0054] The second sublayer and the solid electrolyte layer comprise the same type of solid electrolyte material.

[0055] By setting a first sublayer with the same type of electrode active material as the electrode active material layer and a second sublayer with the same type of solid electrolyte material as the solid electrolyte layer in the interface functional layer, the compatibility between the interface functional layer and the electrode layer and the solid electrolyte layer can be better improved, the interfacial impedance between the electrode layer and the solid electrolyte layer can be reduced, and thus the aforementioned electrochemical performance of the battery can be better improved.

[0056] In some embodiments, the mass percentage of the electrode active material in the first sublayer is higher than that in the second sublayer; the mass percentage of the solid electrolyte material in the second sublayer is higher than that in the first sublayer.

[0057] By taking advantage of the fact that the content of electrode active material in the first sublayer is higher than that in the second sublayer, the mass ratio of electrode active material decreases sequentially from the corresponding electrode layer, the interface functional layer to the solid electrolyte layer. By taking advantage of the fact that the content of solid electrolyte material in the second sublayer is higher than that in the first sublayer, the mass ratio of solid electrolyte material increases sequentially from the solid electrolyte layer, the interface functional layer to the corresponding electrode layer. These characteristics are more conducive to reducing interfacial impedance.

[0058] In some implementations, the first sublayer and the second sublayer have an interlocking interface.

[0059] By interleaving the interfaces of the first and second sublayers, the interfacial contact area can be increased, which is beneficial to improving interfacial adhesion and bonding, and reducing interfacial impedance. This facilitates better layer-to-layer composite between the electrode layer and the solid electrolyte layer, thereby better reducing the interfacial impedance between the electrode layer and the solid electrolyte layer. This, in turn, can better improve the aforementioned electrochemical performance of the battery, including improving battery cycle performance, as well as improving discharge capacity and rate performance.

[0060] In some embodiments, at least one of the positive electrode active material layer and the negative electrode active material layer includes an organic component;

[0061] The density of the solid electrolyte layer is denoted as K. E Satisfying K E ≥90%.

[0062] In some implementations, K E ≥97%.

[0063] When a solid electrolyte layer is prepared using a positive or negative electrode layer as a substrate, by controlling the presence of organic components in the positive or negative electrode active material layer, surface treatment can be used to remove organic binders and form exhaust microchannels. This is beneficial for improving the density during subsequent pressing treatments (such as warm isostatic pressing), thereby significantly improving the interfacial impedance within the solid electrolyte layer, and further enhancing the aforementioned electrochemical performance of the battery.

[0064] In some embodiments, the solid electrolyte layer comprises an electrolyte organic component, and the solid-state battery satisfies at least one of the following characteristics:

[0065] (b1) Let the density of the positive electrode active material layer be K.P Satisfying K P ≥90%;

[0066] (b2) Let the density of the negative electrode active material layer be K. N Satisfying K N ≥90%.

[0067] In some embodiments, the solid-state battery satisfies at least one of the following characteristics:

[0068] K P ≥97%;

[0069] K N ≥97%.

[0070] When a positive or negative electrode layer is prepared using a solid electrolyte layer as a substrate, by controlling the presence of organic components in the solid electrolyte layer, surface treatment can be used to remove organic binders and form exhaust microchannels, which is beneficial to improving the density during subsequent pressing treatment (such as warm isostatic pressing), thereby significantly improving the interfacial impedance within the positive or negative electrode layer, and further improving the aforementioned electrochemical performance of the battery.

[0071] In some embodiments, the solid-state battery is an all-solid-state battery.

[0072] In a second aspect of this application, various methods for preparing solid-state batteries are provided.

[0073] In some embodiments, a method for preparing a solid-state battery is provided, which includes the following steps:

[0074] The initial active layer of the negative electrode located on at least one side of the negative electrode sheet is etched to form a rough surface of the negative electrode with a negative electrode recess. The negative electrode sheet after the etching process includes a negative electrode protrusion corresponding to the negative electrode recess. The initial active layer of the negative electrode includes degradable organic components. After the etching process, the content of degradable organic components in the negative electrode protrusion decreases.

[0075] An electrolyte pre-coating is provided on the rough surface of the negative electrode. The electrolyte pre-coating is pressed so that the negative electrode protrusion and the portion of the electrolyte pre-coating filling the corresponding negative electrode recess together form a negative electrode interface functional layer, and the remaining portion of the electrolyte pre-coating forms a solid electrolyte layer.

[0076] A positive electrode layer is formed on the surface of the solid electrolyte layer away from the negative electrode interface functional layer.

[0077] A solid electrolyte layer and a positive electrode layer can be sequentially prepared on a negative electrode sheet containing a biodegradable organic component as the initial active layer. By etching the initial active layer on the surface of the negative electrode sheet, the biodegradable organic component is partially or completely removed, reducing the organic component content. On the one hand, the decrease in organic component content can lead to an increase in the inorganic component content in the etched area on the negative electrode surface, thereby improving the conductivity of the negative electrode surface, reducing interfacial impedance, and improving the battery's electrochemical performance, including cycle performance. In addition, it is also beneficial to improve discharge capacity and rate performance. On the other hand, a negative electrode rough surface with a negative electrode recess can be formed on the negative electrode surface. When further preparing the solid electrolyte layer, a ventable microchannel can be formed between the formed solid electrolyte layer and the negative electrode rough surface. During subsequent pressing processes (such as warm isostatic pressing), these microchannels can be used to vent, increasing the pressing degree of the solid electrolyte layer and improving the density of the formed solid electrolyte layer. In addition, the negative electrode rough surface can also increase the contact area between the solid electrolyte layer and the solid electrolyte layer, which is also beneficial to reducing interfacial impedance and thus improving battery performance, including at least improving battery cycle performance.

[0078] In some embodiments, when the solid electrolyte layer is formed based on the etched negative electrode sheet, the density of the solid electrolyte layer is denoted as K. E Satisfying K E ≥90%, with an etching depth of 1μm~50μm.

[0079] In some implementations, K E ≥97%, with an etching depth of 3μm~40μm.

[0080] By controlling the etching depth of the negative electrode sheet, the roughness of the negative electrode surface can be adjusted, allowing the ventable microchannels to have suitable dimensions and resulting in a higher density of the solid electrolyte layer formed based on the etched negative electrode sheet. Furthermore, it allows for more complete interlocking of materials at the interface, which also contributes to improving the density of the solid electrolyte layer. In particular, controlling the etching depth to 3μm–40μm is more conducive to providing appropriately sized ventable microchannels and promoting more complete interlocking of interface materials, thus further enhancing the density of the solid electrolyte layer.

[0081] In some embodiments, a method for preparing a solid-state battery is provided, which includes the following steps:

[0082] The positive electrode active initial layer located on at least one side surface of the positive electrode sheet is etched to form a positive electrode rough surface with a positive electrode recess. The positive electrode sheet after the etching process includes a positive electrode protrusion corresponding to the positive electrode recess. The positive electrode active initial layer includes degradable organic components. After the etching process, the content of degradable organic components in the positive electrode protrusion decreases.

[0083] An electrolyte pre-coating is provided on the rough surface of the positive electrode. The electrolyte pre-coating is pressed so that the positive electrode protrusion and the portion of the electrolyte pre-coating filling the corresponding positive electrode recess together form a positive electrode interface functional layer, and the remaining portion of the electrolyte pre-coating forms a solid electrolyte layer.

[0084] A negative electrode layer is formed on the surface of the solid electrolyte layer away from the positive electrode interface functional layer.

[0085] A solid electrolyte layer and a positive electrode layer can be sequentially prepared on a positive electrode sheet containing a biodegradable organic component as the initial active layer. By etching the initial active layer on the surface of the positive electrode sheet, the biodegradable organic component is partially or completely removed, reducing the organic component content. On the one hand, the decrease in organic component content can lead to an increase in the inorganic component content in the etched area on the positive electrode surface, thereby improving the conductivity of the positive electrode surface, reducing interfacial impedance, and improving the battery's electrochemical performance, including cycle performance. In addition, it is also beneficial to improve discharge capacity and rate performance. On the other hand, a positive electrode rough surface with a positive electrode recess can be formed on the positive electrode surface. When further preparing the solid electrolyte layer, a ventable microchannel can be formed between the formed solid electrolyte layer and the positive electrode rough surface. During subsequent pressing processes (such as warm isostatic pressing), these microchannels can be used to vent, increasing the pressing degree of the solid electrolyte layer and improving the density of the formed solid electrolyte layer. In addition, the positive electrode rough surface can also increase the contact area between the solid electrolyte layer and the solid electrolyte layer, which is also beneficial to reducing interfacial impedance and thus improving battery performance, including at least improving battery cycle performance.

[0086] In some embodiments, when the solid electrolyte layer is formed based on the etched positive electrode, the density of the solid electrolyte layer is denoted as K. E Satisfying K E ≥90%, with an etching depth of 1μm~50μm.

[0087] In some implementations, K E ≥97%, with an etching depth of 3μm~40μm.

[0088] By controlling the etching depth of the positive electrode, the roughness of the positive electrode surface can be adjusted, allowing the ventable microchannels to have suitable dimensions. This results in a higher density of the solid electrolyte layer formed based on the etched positive electrode. Furthermore, it allows for more complete interlocking of materials at the interface, further enhancing the density of the solid electrolyte layer. Specifically, controlling the etching depth to 3μm–40μm is particularly beneficial for providing appropriately sized ventable microchannels and promoting more complete interlocking of interface materials, thus further improving the density of the solid electrolyte layer.

[0089] In some embodiments, a method for preparing a solid-state battery is provided, which includes the following steps:

[0090] A solid electrolyte membrane is provided, comprising a first surface and a second surface that are opposite to each other; wherein the solid electrolyte membrane comprises a degradable organic component;

[0091] The first surface of the solid electrolyte membrane is etched to form a first rough surface with a first concave portion. The solid electrolyte membrane after the etching treatment includes a first convex portion corresponding to the first concave portion. After the etching treatment, the content of degradable organic components in the first convex portion decreases.

[0092] A first electrode pre-coating layer is formed on the first surface of the solid electrolyte membrane after the etching process. The first electrode pre-coating layer is pressed so that the first protrusion and the portion of the first electrode pre-coating layer filled in the corresponding first recess together form a first interface functional layer, and the remaining portion of the first electrode pre-coating layer forms a first electrode layer.

[0093] A second electrode layer is formed on the second surface of the solid electrolyte membrane.

[0094] Two electrode layers can be sequentially fabricated on a solid electrolyte membrane containing biodegradable organic components. By etching the surface of the solid electrolyte membrane, the biodegradable organic components are partially or completely removed, reducing the organic component content. On the one hand, the decrease in organic component content can lead to an increase in the inorganic component content in the etched area on the surface of the solid electrolyte membrane, thereby improving the conductivity of the solid electrolyte membrane surface, reducing interfacial impedance, and improving the battery's electrochemical performance, including cycle performance. In addition, it is also beneficial to improve discharge capacity and rate performance. On the other hand, a first rough surface with concave areas can be formed on the surface of the solid electrolyte membrane. When further fabricating the first electrode layer, a ventable microchannel can be formed between the formed first electrode layer and the first rough surface. During subsequent pressing processes (such as warm isostatic pressing), these microchannels can be used to vent, increasing the pressing degree of the first electrode layer and improving the density of the formed first electrode layer. Furthermore, the first rough surface can also increase the contact area between the first electrode layer and the first electrode layer, which is also beneficial to reducing interfacial impedance and thus improving battery performance, including at least improving battery cycle performance.

[0095] In some embodiments, forming a second electrode layer on the second surface of the solid electrolyte membrane includes the following steps:

[0096] The second surface of the solid electrolyte membrane is etched to form a second rough surface with a second concave portion. The solid electrolyte membrane after the etching treatment includes a second convex portion corresponding to the second concave portion. After the etching treatment, the content of degradable organic components in the second convex portion decreases.

[0097] A second electrode pre-coating is formed on the second surface of the solid electrolyte membrane after etching. The second electrode pre-coating is pressed so that the second protrusion and the portion of the second electrode pre-coating filled in the corresponding second recess together form a second interface functional layer, and the remaining portion of the second electrode pre-coating forms the second electrode layer.

[0098] When forming a second electrode on the other side of the solid electrolyte membrane, the content of degradable organic components in the etched area can be reduced and a second rough surface can be formed by etching the surface of the solid electrolyte membrane. This improves the conductivity of the solid electrolyte membrane surface, reduces the interfacial impedance, and forms ventable microchannels between the formed second electrode layer and the second rough surface. During subsequent pressing processes (such as warm isostatic pressing), these microchannels can be used to vent, increasing the pressing degree of the second electrode layer and improving the density of the formed second electrode layer. In addition, the second rough surface can also increase the contact area with the second electrode layer, which is also beneficial to reducing the interfacial impedance and thus improving battery performance, including at least improving battery cycle performance.

[0099] In some embodiments, the first electrode layer is a positive electrode layer, or the first electrode layer is a negative electrode layer.

[0100] Based on a solid electrolyte membrane, either the positive electrode layer or the negative electrode layer can be formed first.

[0101] In some embodiments, the surface of the solid electrolyte membrane near the positive electrode layer is etched before the positive electrode layer is formed; the density of the positive electrode layer is denoted as K. P Satisfying K P ≥90%, with an etching depth of 1μm~50μm.

[0102] In some implementations, K P ≥97%, with an etching depth of 3μm~40μm.

[0103] By controlling the etching depth of the solid electrolyte layer, the density of the positive electrode layer formed based on the etched solid electrolyte film can be adjusted.

[0104] In some embodiments, the surface of the solid electrolyte membrane near the negative electrode layer is etched before the negative electrode layer is formed; the density of the negative electrode layer is denoted as K. N Satisfying KN ≥90%, with an etching depth of 1μm~50μm;

[0105] In some implementations, K N ≥97%, with an etching depth of 3μm~40μm.

[0106] By controlling the etching depth of the solid electrolyte layer, the density of the negative electrode layer formed based on the etched solid electrolyte film can be adjusted.

[0107] In some embodiments, the etching process includes one or more of plasma processing and laser processing.

[0108] In a third aspect of this application, an electrical device is provided, comprising at least one of the solid-state battery described in the first aspect of this application and a solid-state battery prepared by the method described in the second aspect of this application.

[0109] Details of one or more embodiments or examples of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0110] To better describe and illustrate the embodiments, examples, or models provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments, examples, or models, or the best mode of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. It should also be noted that the drawings are drawn in a simplified form and are only intended to facilitate and clarify the illustration of this application. The various dimensions of each part shown in the drawings are arbitrarily shown and may be precise or not drawn to scale. For example, the dimensions of parts are appropriately exaggerated in some places in the drawings to make the illustration clearer. Unless otherwise specified, the parts in the drawings are not drawn to scale. This application does not limit every dimension of every part. In the following description, the same reference numerals denote the same parts.

[0111] In the attached diagram:

[0112] Figure 1 is a schematic diagram of the structure of a solid-state battery cell in one embodiment of this application, wherein an interface functional layer is provided between the solid electrolyte layer and the electrode layer on one side.

[0113] Figure 2 is a schematic diagram of the structure of a solid-state battery cell in one embodiment of this application, wherein a positive electrode interface functional layer is provided between the solid electrolyte layer and the positive electrode layer.

[0114] Figure 3 is a schematic diagram of the structure of a solid-state battery cell in one embodiment of this application, wherein a negative electrode interface functional layer is provided between the solid electrolyte layer and the negative electrode layer.

[0115] Figure 4 is a schematic diagram of the structure of a solid-state battery cell in one embodiment of this application. An interface functional layer is provided between the solid electrolyte layer and the positive electrode layer and the negative electrode layer, that is, a positive electrode interface functional layer and a negative electrode interface functional layer are provided at the same time.

[0116] Figure 5 is a schematic diagram of the structure of a solid-state battery cell in one embodiment of this application. A negative electrode interface functional layer is provided between the solid electrolyte layer and the negative electrode layer. The interface functional layer includes a first sub-layer and a second sub-layer. The first sub-layer is in contact with the negative electrode layer, and the second sub-layer is in contact with the solid electrolyte layer. At this time, the second sub-layer is located between the first sub-layer and the solid electrolyte layer.

[0117] Figure 6 is a schematic diagram of the structure of a solid-state battery cell in one embodiment of this application. A positive electrode interface functional layer is provided between the solid electrolyte layer and the positive electrode layer. The interface functional layer includes a first sub-layer and a second sub-layer. The first sub-layer is in contact with the positive electrode layer, and the second sub-layer is in contact with the solid electrolyte layer. At this time, the second sub-layer is located between the first sub-layer and the solid electrolyte layer.

[0118] Figure 7 is a schematic diagram of the structure of an electrode sheet in one embodiment of this application. The electrode sheet includes a current collector and an initial electrode activity layer.

[0119] Figure 8 is a schematic flowchart of a solid-state battery preparation method according to an embodiment of this application.

[0120] Figure 9 is a schematic diagram of a solid-state battery cell according to an embodiment of this application.

[0121] Figure 10 is an exploded view of a solid-state battery cell according to an embodiment of this application, as shown in Figure 9.

[0122] Figure 11 is a schematic diagram of a battery module according to an embodiment of this application.

[0123] Figure 12 is a schematic diagram of a battery pack according to one embodiment of this application.

[0124] Figure 13 is an exploded view of a battery pack according to an embodiment of this application, as shown in Figure 12.

[0125] Figure 14 is a schematic diagram of an electrical device using a solid-state battery as a power source according to an embodiment of this application.

[0126] Explanation of reference numerals in the attached figures:

[0127] 120, Electrode layer; 22, Interface functional layer; 222, Positive electrode interface functional layer; 223, Negative electrode interface functional layer; 201, First sub-layer; 202, Second sub-layer; 200, Positive electrode layer; 100, Solid electrolyte layer; 300, Negative electrode layer; 12, Electrode sheet; 121, Current collector; 122, Initial electrode activity layer; 30, Negative electrode sheet; 310, Negative electrode current collector; 32, Initial negative electrode activity layer; 320, Negative electrode active material layer; 330, Negative electrode protrusion; 332, Negative electrode recess; 110, Electrolyte pre-coating; 1, Battery pack; 2, Upper casing; 3, Lower casing; 4, Battery module; 5, Solid-state battery cell; 51, Housing; 52, Solid-state cell; 53, Cover plate; 6, Electrical device. Detailed Implementation

[0128] The following describes in detail some embodiments of the solid-state battery, its fabrication method, and its electrical device, with appropriate reference to the accompanying drawings. However, some unnecessary details may be omitted. For example, detailed descriptions of well-known facts and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0129] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints. Any endpoint can be included or excluded independently and can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0" and "5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when describing a parameter as an integer ≥ 2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 for that parameter. For instance, when describing a parameter as an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0130] In this application, the term "numerical value," unless otherwise specified, includes the number itself and its reasonable approximations. The definition of "numerical value" can apply to discrete numerical points as well as the endpoints of a numerical range. Unless otherwise specified, the term "approximation" covers a numerical interval based on a reasonable range of fluctuations of the number itself. This reasonable range of fluctuations can vary depending on the type and magnitude of the number. This reasonable range of fluctuations can be reasonably determined based on the accuracy of the testing or measurement method. Therefore, when referring to numerical values ​​or numerical ranges, unless otherwise specified, it should be understood that the numerical value includes its reasonable approximations, and the numerical range includes reasonable approximations at both endpoints. Those skilled in the art will understand that acceptable fluctuation ranges of the relevant approximations can be included within the definition of the numerical value or the numerical range. In this application, unless otherwise specified, "N1" can be reasonably understood as "about N1," and "N1~N2" can be reasonably understood as "about N1 to about N2," where N1 and N2 are two unequal numerical values. For example, in some cases, it is reasonable to include approximate values ​​within the approximate range into the range defined by the approximate value range due to one or more factors such as reasonable deviations allowed in the field and the precision of instrument control; for example, "temperature is 20℃~30℃" can be understood as "approximately 20℃ to approximately 30℃"; furthermore, taking "20℃" as the endpoint and its approximate value as ±1℃ as an example, approximate values ​​such as 19℃ and 19.5℃ within the approximate range corresponding to "approximately 20℃" should also be included in the range indicated by 20℃~30℃.

[0131] In this application, unless otherwise specified, "about" means within a reasonable range above and below the stated number, and the range of fluctuation may vary depending on the type and value of the stated number. For example, a range of ±10%, ±5%, ±2%, ±1%, etc., may be allowed. For example, taking "about 20°C" and its approximation as ±1°C, approximate values ​​such as 19°C, 19.5°C, etc., within the approximation range indicated by "about 20°C" should also be included in the range indicated by "about 20°C".

[0132] In this application, the terms "multiple," "various," "multiple items," "several," etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more (greater than or equal to) two. It can be understood that when "any number of" items are involved, it refers to any suitable combination of multiple items, that is, a combination of "any number of" items in a manner that does not conflict and enables the implementation of this application.

[0133] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0134] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The term "implementation" as used herein has a similar understanding.

[0135] Those skilled in the art will understand that the order in which the steps are written in the methods of various embodiments or examples does not imply a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of this application may be performed sequentially or randomly, but are preferably performed sequentially. For example, if method M includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, method M may also include step (c), meaning that step (c) can be added to method M in any order. For example, method M may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0136] In this application, open-ended technical features or solutions described using terms such as "containing," "comprising," or "including" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, if 'a' includes a1, a2, and a3, it may also include other members or exclude additional members unless otherwise specified. This can be considered as providing both features or solutions where "a consists of a1, a2, and a3" or "a is selected from a1, a2, and a3," and features or solutions where "a includes not only a1, a2, and a3, but also other members."

[0137] In this application, unless otherwise specified, M (e.g., m1) means that m1 is a non-limiting example of M, and it is understood that M is not limited to m1.

[0138] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "with" or "without." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. Unless otherwise specified, the descriptions such as "optionally include" and "optionally contain" in this application, taking "optionally include" as an example, mean "may include or not include."

[0139] In this application, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. Any and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "M and / or N" represents the group consisting of M, N, and "a combination of M and N". "Containing M and / or N" can mean "containing M, containing N, and containing both M and N", or "containing M, containing N, or containing both M and N", and can be appropriately understood according to the context.

[0140] The terms “combinations of,” “any combination of,” and “any combination of” used in this article include all suitable combinations of any two or more of the listed items.

[0141] In this document, the term "suitable" in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the technical solution that enables the implementation of this application.

[0142] In this document, terms such as "preferred," "better," "more suitable," "ideal," "good," and "superior" are merely descriptions of more effective implementation methods or embodiments, and should be understood not to limit the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "preferred" term shall be independent.

[0143] In this application, terms such as "further," "even more," "especially," "for example," "as," "example," and "exemplary" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0144] In this application, the terms "first aspect," "second aspect," "third aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0145] In this application, unless otherwise expressly specified and limited, the phrase "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In this application, unless otherwise expressly specified and limited, the phrase "above" or "below" the second feature can indicate a horizontal positional relationship, or it can simply indicate the existence of an attachment relationship without specifying a horizontal positional relationship.

[0146] In this application, the term "room temperature" generally refers to 4℃ to 35℃, and may refer to 20℃ ± 5℃. In some embodiments or examples of this application, room temperature refers to 20℃ to 30℃.

[0147] In this application, if the unit for a data range is only followed by the right endpoint, it indicates that the units for the left and right endpoints are the same. For example, 3~5h or 3-5h both mean that the unit for the left endpoint "3" and the right endpoint "5" is h (hours), and both have the same meaning as 3h~5h. Furthermore, similar descriptions of other parameters such as temperature and size are interpreted in the same way.

[0148] The weight or mass of the relevant components mentioned in the embodiments or examples of this application can refer not only to the content of each component, but also to the proportional relationship of weight or mass between the components. Therefore, as long as the content of the relevant components is scaled up or down proportionally according to the embodiments or examples of this application, it is within the scope described in this application. Furthermore, the mass involved in the embodiments or examples of this application can be a mass unit known in the chemical industry, such as microgram (μg), milligram (mg), gram (g), kilogram (kg). Unless otherwise specified, the mass ratio is equal to the corresponding weight ratio. For example, if the mass of substance A is m1 and the weight is W1, and the mass of substance B is m2 and the weight is W2, then the mass ratio m1 / m2 is numerically equal to the corresponding weight ratio W1 / W2.

[0149] In this application, unless otherwise specified, wt% represents a weight percentage by weight, which is numerically equal to the corresponding mass percentage by mass. In this application, the weight percentage denoted as "0" has the same meaning as "0wt%" and can be used interchangeably.

[0150] 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 represented as ">", and "less than" can be equivalently represented as "<". In this application, unless otherwise specified, "greater than or equal to" and "≥" can be considered as providing two additional solutions: "greater than" and "equal to". In this application, unless otherwise specified, "less than or equal to" and "≤" can be considered as providing two additional solutions: "less than" and "equal to".

[0151] In this application, the exemplary descriptions such as "in some implementations (or embodiments)" and "in one implementation (or embodiment)" may cover, but are not limited to, the following meanings: these solutions can be combined with other solutions in a suitable manner to form new technical solutions.

[0152] The improvement described in any part of the context of this application is not intended to be limited to any theory.

[0153] In traditional solid-state batteries, the interface compatibility between the solid electrolyte layer and the electrode layers (positive electrode layer and / or negative electrode layer) is usually poor, resulting in poor interface adhesion, increased battery impedance, and may even lead to the separation between structural layers, resulting in less than ideal battery performance such as cycle performance.

[0154] According to various embodiments and examples of this application, this application provides at least one solid-state battery, a method for preparing the same, and an electrical device thereof. This solid-state battery exhibits improved cycle performance.

[0155] In some embodiments, the solid-state battery includes a solid electrolyte layer and a positive electrode layer and a negative electrode layer located on both sides of the solid electrolyte layer; an interface functional layer is disposed between the solid electrolyte layer and at least one electrode layer; the interface functional layer located between the positive electrode layer and the solid electrolyte layer is referred to as the positive electrode interface functional layer, and the interface functional layer located between the negative electrode layer and the solid electrolyte layer is referred to as the negative electrode interface functional layer; the mass percentages of the organic components in the positive electrode interface functional layer, the negative electrode interface functional layer, the positive electrode active material layer in the positive electrode layer, the negative electrode active material layer in the negative electrode layer, and the solid electrolyte layer can be respectively denoted as f. m1 f m2 f mP f mN and f mE ; where, when the positive electrode interface functional layer exists, f m1 Less than f mP and f mE At least one of them; when the negative electrode interface functional layer exists, f m2 Less than f mN and f mEAt least one of them. This solid-state battery has improved cycle performance.

[0156] Unless otherwise specified, the term "solid-state battery" in this application refers to a battery in which the electrolyte includes a solid electrolyte. Typically, a solid-state battery includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. During charging and discharging, active ions repeatedly insert and extract between the positive and negative electrode layers. The solid electrolyte layer acts as a conductor of ions between the positive and negative electrode layers and also isolates them, preventing short circuits. Therefore, a separator, as found in traditional lithium-ion batteries, is not required in solid-state batteries. Solid-state batteries use a non-flammable solid electrolyte instead of the organic electrolyte in traditional liquid lithium-ion batteries, significantly improving battery safety. In addition to enhanced safety, solid-state batteries are better suited for high-energy-density positive and negative electrode materials and reduce system weight, thus facilitating improvements in energy density.

[0157] In this application, unless otherwise specified, "solid electrolyte" refers to an electrolyte material or substance that exists in solid form during the storage and fabrication of solid-state batteries and their components, as well as during the operation of solid-state batteries. This includes, but is not limited to, solid electrolytes existing in solid form at room temperature.

[0158] In this application, unless otherwise specified, "electrode layer" includes electrode active material. The electrode layer can be a positive electrode layer or a negative electrode layer, and "electrode active material" in the electrode layer refers to a material capable of reversibly inserting and extracting active ions. Unless otherwise specified, "negative electrode active material" refers to a material used in the negative electrode layer capable of reversibly inserting and extracting active ions; "positive electrode active material" refers to a material used in the positive electrode layer capable of reversibly extracting and inserting active ions. During solid-state battery charging, active ions are extracted from the positive electrode, pass through the solid electrolyte layer, and insert into the negative electrode; while during solid-state battery discharging, active ions are extracted from the negative electrode and insert into the positive electrode. The active ions are not particularly limited; non-limitingly, the active ions can be lithium ions, corresponding to a lithium-ion solid-state battery.

[0159] In this application, unless otherwise specified, "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 circumstances, the electrode active material layer may refer to either the positive electrode active material layer or the negative electrode active material layer. It is understood that the positive electrode active material layer contains positive electrode active material, and the negative electrode active material layer contains negative electrode active material.

[0160] In some embodiments of the first aspect of this application, a solid-state battery is provided, which includes a solid electrolyte layer and two electrode layers located on both sides of the solid electrolyte layer, wherein one electrode layer is a positive electrode layer and the other electrode layer is a negative electrode layer; the positive electrode layer includes a positive electrode active material layer and the negative electrode layer includes a negative electrode active material layer;

[0161] An interface functional layer is provided between a solid electrolyte layer and at least one electrode layer; the interface functional layer located between the positive electrode layer and the solid electrolyte layer is referred to as the positive electrode interface functional layer, and the interface functional layer located between the negative electrode layer and the solid electrolyte layer is referred to as the negative electrode interface functional layer.

[0162] The mass percentage of organic components in the functional layer of the positive electrode interface is denoted as f. m1 The mass percentage of organic components in the functional layer of the negative electrode interface is denoted as f. m2 The mass percentage of organic components in the positive electrode active material layer is denoted as f. mP The mass percentage of organic components in the negative electrode active material layer is denoted as f. mN The mass percentage of organic components in the solid electrolyte layer is denoted as f. mE ;

[0163] in,

[0164] When the positive electrode interface functional layer exists, f m1 Less than f mP and f mE At least one of them;

[0165] When the negative electrode interface functional layer exists, f m2 Less than f mN and f mE At least one of them.

[0166] In this application, "organic component" has the well-known meaning in the art, which has a carbon-containing skeleton. "Inorganic component" also has the well-known meaning in the art, which does not have a carbon-containing skeleton.

[0167] In this application, unless otherwise specified, the following substances are classified as "organic components": organic binders, organic dispersants, etc. Non-limiting examples of organic binders may include one or more of polyvinylidene fluoride, styrene-butadiene rubber latex, carboxymethyl cellulose, sodium carboxymethyl cellulose, sodium alginate, polyvinyl alcohol, polymethyl methacrylate, hydrogenated nitrile butadiene rubber, polytetrafluoroethylene, polyacrylic acid, etc.; non-limiting examples of organic dispersants may include one or more of cationic wetting and dispersing agents, anionic wetting and dispersing agents, and amphoteric wetting and dispersing agents; wherein, cationic wetting and dispersing agents may include, but are not limited to, one or more of amine salts, quaternary ammonium salts, and pyridinium salts; anionic wetting and dispersing agents may include, but are not limited to, one or more of fatty acid salts, sulfate ester salts, and sulfonates; and amphoteric wetting and dispersing agents may include, but are not limited to, phosphate ester type polymers.

[0168] It should be noted that sodium carboxymethyl cellulose can be used as a thickener. Since it also has a certain degree of viscosity, it is also included in the category of organic binders in this application.

[0169] In some embodiments, the organic component is a biodegradable organic component. The definition of a biodegradable organic component can also be found in the context of this application.

[0170] In this application, unless otherwise specified, the "interface functional layer" is located between the solid electrolyte layer and at least one electrode layer on either side, that is, the interface functional layer is located at at least one of the following positions: (position P1) between the solid electrolyte layer and the negative electrode layer; (position P2) between the solid electrolyte layer and the positive electrode layer. The interface functional layer located between the positive electrode layer and the solid electrolyte layer is denoted as the "positive electrode interface functional layer," and the interface functional layer located between the negative electrode layer and the solid electrolyte layer is denoted as the "negative electrode interface functional layer." Compared with adjacent structural layers, the interface functional layer has a lower content of organic components and, correspondingly, a higher content of inorganic components. Based on this, the interface functional layer has higher ion-conducting and electron-conducting capabilities and a higher overall conductivity compared with adjacent structural layers.

[0171] This solid-state battery incorporates an interfacial functional layer between a solid electrolyte layer and at least one electrode layer. The organic component content in this interfacial functional layer is lower than that in at least one of the solid electrolyte layer and adjacent electrode active material layers. This allows the interfacial functional layer to exhibit better charge transfer performance, improved ion and electron conduction, and higher overall conductivity. It also enhances the interfacial compatibility between the electrode layer and the solid electrolyte layer, reduces interfacial impedance, and thus improves the battery's electrochemical performance, including cycle performance. Furthermore, it also contributes to improved discharge capacity and rate performance.

[0172] Unless otherwise specified in this application, the types and contents of the "organic components" in the "interface functional layer," "positive electrode layer," and "negative electrode layer" may be tested and analyzed using one or more methods, including but not limited to: Fourier transform infrared (FT-IR) spectroscopy, ultraviolet spectroscopy, and proton nuclear magnetic resonance (NMR) spectroscopy. 1 Methods include ¹H NMR, X-ray diffraction (XRD), gel permeation chromatography (GPC), high-performance liquid chromatography (HPLC), and mass spectrometry. The sample preparation and testing methods for these methods are known to those skilled in the art, and the test parameters can be appropriately adjusted according to the characteristics of the analyte. Materials from the corresponding structural layers can be extracted from the electrodes disassembled from the battery for testing, or materials in the electrode active material layers of electrode sheets that have not yet been assembled into a battery can be tested. The battery to be tested can be a battery that has been prepared but not yet used, or a battery that has been packaged but not yet discharged or charged / discharge cycled. Alternatively, the battery to be tested can be a battery that has been prepared and discharged or charged / discharge cycled.

[0173] In some embodiments, a solid-state battery includes a solid electrolyte layer and electrode layers located on both sides of the solid electrolyte layer, with an interface functional layer provided between the solid electrolyte layer and one of the electrode layers.

[0174] In some embodiments, a solid-state battery includes a positive electrode layer, a positive electrode interface functional layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially.

[0175] In some embodiments, a solid-state battery includes a positive electrode layer, a solid electrolyte layer, a negative electrode interface functional layer, and a negative electrode layer stacked sequentially.

[0176] In some embodiments, a solid-state battery includes a positive electrode layer, a positive electrode interface functional layer, a solid electrolyte layer, a negative electrode interface functional layer, and a negative electrode layer stacked sequentially.

[0177] In some embodiments, the organic component includes one or more of organic binders and organic dispersants. Non-limitingly, the organic binder may include, but is not limited to, one or more of polyvinylidene fluoride, styrene-butadiene rubber latex, carboxymethyl cellulose, sodium carboxymethyl cellulose, sodium alginate, polyvinyl alcohol, polymethyl methacrylate, hydrogenated nitrile butadiene rubber, polytetrafluoroethylene, and polyacrylic acid. Non-limitingly, the organic dispersant may include one or more of cationic wetting and dispersing agents, anionic wetting and dispersing agents, and amphoteric wetting and dispersing agents; wherein, cationic wetting and dispersing agents may include, but is not limited to, one or more of amine salts, quaternary ammonium salts, and pyridinium salts; anionic wetting and dispersing agents may include, but is not limited to, one or more of fatty acid salts, sulfate esters, and sulfonates; and amphoteric wetting and dispersing agents may include, but is not limited to, phosphate ester type polymers. The cationic wetting and dispersing agents such as amine salts, quaternary ammonium salts, and pyridinium salts, and the anionic wetting and dispersing agents such as sulfate esters and sulfonates described herein, unless otherwise specified, refer to the corresponding substances containing organic groups. A non-limiting example of a fatty acid salt is sodium oleate.

[0178] Organic components such as organic binders and organic dispersants can be set in the electrode active material layer adjacent to the interface functional layer, and the content of these organic components can be controlled to be lower in the interface functional layer, thereby giving the interface functional layer better ion conduction and electron conduction properties.

[0179] By selecting the aforementioned organic components and setting a content difference between adjacent electrode layers and interface functional layers, it is possible to balance good interfacial contact and structural stability within the electrode layers with high electrical conductivity in the interface functional layers.

[0180] In some embodiments, the thickness of any interface functional layer is less than or equal to 50 μm; optionally, the thickness of any interface functional layer is 1 μm to 50 μm. Non-limitingly, the thickness of any interface functional layer may also be any of the following thicknesses or a range selected from any two of the following thicknesses: 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 15 μm, 16 μm, 18 μm, 20 μm, 24 μm, 25 μm, 26 μm, 28 μm, 30 μm, 32 μm, 34 μm, 35 μm, 36 μm, 38 μm, 40 μm, 45 μm, 50 μm, etc.

[0181] By controlling the thickness of the interface functional layer within the aforementioned range, it is beneficial to improve interface compatibility, reduce interface impedance, and achieve better interface adhesion, which in turn helps solid-state batteries to have better structural stability.

[0182] Unless otherwise specified in this application, the structure, internal interface, and thickness of the "interface functional layer" can be tested and analyzed using methods such as scanning electron microscopy (SEM) and computed tomography (CT). The X-ray source for CT can be X-ray beam, gamma ray, ultrasound, etc. Liquid nitrogen can be used to quench the solid-state battery cell along its thickness, allowing for microscopic morphological observation of the cross-section. Non-limitingly, instruments including, but not limited to, focused electron beam (FIB) microscopes (non-limiting examples such as the FEI Scios 2HiVac device) and ion cross-section polishers (non-limiting examples such as the JEOL IB-09010CP argon ion cross-section polisher and IB-19500CP ion cross-section polisher) can be used to process the solid-state battery cell to obtain the cross-section to be observed. Microscopic morphology observation methods can employ instruments or equipment including but not limited to scanning electron microscopy (SEM) technology. In particular, high-resolution field emission scanning electron microscopes can be used. Examples of non-limiting SEM instruments include the Sigma 300 scanning electron microscope and the Apreo 2SEM field emission scanning electron microscope from ZEISS GmbH, Germany.

[0183] In some implementations, a positive electrode interface functional layer exists, f m1 <f mP At this point, σ1 > σ can be achieved. P .

[0184] In some implementations, a positive electrode interface functional layer exists, f m1 <f mE At this point, σ1 > σ can be achieved. E .

[0185] In some implementations, a positive electrode interface functional layer exists, f m1 <f mP And f m1 <f mE At this point, σ1 > σ can be achieved. P And σ1>σ E .

[0186] When the content of organic components in the positive electrode interface functional layer is lower than that in both the positive electrode active material layer and the solid electrolyte layer, the positive electrode interface functional layer can provide better ion conduction and electronic conduction properties, which is more conducive to reducing interface impedance.

[0187] In some implementations, a negative electrode interface functional layer exists, f m2 <f mN At this point, σ² > σ can be achieved. N .

[0188] In some implementations, a negative electrode interface functional layer exists, f m2 <f mE At this point, σ² > σ can be achieved. E .

[0189] In some implementations, a negative electrode interface functional layer exists, f m2 <f mN And f m2 <f mE At this point, σ² > σ can be achieved. N And σ²>σ E .

[0190] In some implementations, solid-state batteries satisfy one or both of the following characteristics:

[0191] The positive electrode interface functional layer exists, f m1 <f mP And f m1 <f mE ;

[0192] The negative electrode interface functional layer exists, f m2 <f mN And f m2 <f mE .

[0193] By controlling the content of organic components in the positive electrode interface functional layer to be lower than that in both the positive electrode active material layer and the solid electrolyte layer, the positive electrode interface functional layer can provide better ion conduction and electronic conduction properties, which is more conducive to reducing interface impedance.

[0194] In this application, unless otherwise specified, the conductivity of the positive electrode interface functional layer is denoted as σ1; the conductivity of the negative electrode interface functional layer is denoted as σ2; ​​and the conductivity of the positive electrode active material layer is denoted as σ P The conductivity of the negative electrode active material layer is denoted as σ. N The conductivity of the solid electrolyte layer is denoted as σ. E .

[0195] The conductivity of the positive electrode interface functional layer material is denoted as σ. 1’ The electrical conductivity of the negative electrode interface functional layer material is denoted as σ. 2’ The electrical conductivity of the positive electrode active material layer is denoted as σ. P’ The electrical conductivity of the negative electrode active material layer is denoted as σ. N’ The conductivity of the solid electrolyte layer material is denoted as σ. E’ .

[0196] In this application, the comparison results of the conductivity of each structural layer can be referenced to the conductivity test results of the material in the corresponding structural layer. Non-limitingly, the battery can be disassembled, powder samples of the structural layer to be tested can be extracted, and ionic conductivity tests can be performed to compare the test results of different structural layers; see the test analysis section of the embodiments below. When σ 1’ >σ P’ When σ1 > σ P When σ 1’ >σ E’ When σ1 > σ E When σ 2’ >σ N’ When σ² > σ N When σ 2’ >σ E’ When σ² > σ E .

[0197] Non-limitingly, the conductivity of the interfacial functional layer, positive electrode layer, negative electrode layer, and solid electrolyte layer can also be tested and analyzed using electrochemical impedance spectroscopy (EIS). The corresponding structural layers can be disassembled from the battery, assembled into a symmetrical battery, and then subjected to EIS testing and analysis. When disassembling to obtain the target structural layer, equipment such as a focused electron beam (FIB) microscope (non-limiting examples include the FEI Scios 2HiVac instrument), an ion cross-section polisher (non-limiting examples include the IB-09010CP argon ion cross-section polisher and the IB-19500CP ion cross-section polisher from JEOL Corporation of Japan), etc., can be used, but are not limited to the aforementioned methods. Non-limitingly, an electrochemical workstation can be used for EIS testing and analysis. EIS is a method for studying electrode process kinetics by applying a small-amplitude sinusoidal potential (or current) as a perturbation signal to the test system under specific conditions and studying the relationship between the corresponding signal and the perturbation signal. Since small-amplitude alternating signals have virtually no effect on the state of the measured system, this method can accurately study the relationship between the process kinetic parameters of each electrode and the electrode state. Those skilled in the art are familiar with EIS testing and analysis methods.

[0198] For example, the conductivity of a solid electrolyte layer can be from about 1 mS / cm to about 10 mS / cm.

[0199] In some implementations, a positive electrode interface functional layer exists, where σ1 is greater than σ. P and σ E At least one of them.

[0200] In some implementations, σ1>σ P Optionally, f m1 <f mP .

[0201] In some implementations, σ1>σ E Optionally, f m1 <f mE .

[0202] In some implementations, σ1>σ P And σ1>σ E Optionally, f m1 <f mP And f m1 <f mE , σ1>σ P And σ1>σ E .

[0203] In some implementations, a positive electrode interface functional layer exists, where σ1>σ P And f m1 <f mP Or, σ1>σ E And f m1 <f mE .

[0204] In some implementations, a negative electrode interface functional layer exists, and σ2 is greater than σ. N and σ E At least one of them.

[0205] In some implementations, σ2>σ N Optionally, f m2 <f mN .

[0206] In some implementations, σ2>σ E Optionally, f m2 <f mE .

[0207] In some implementations, σ2>σ N And σ² > σ E Optionally, f m2 <f mN And f m2 <f mE , σ2>σ N And σ² > σ E .

[0208] In some implementations, a negative electrode interface functional layer exists, and σ2>σ N And f m2 <f mN Or, σ²>σ E And f m2 <f mE .

[0209] In some implementations, solid-state batteries satisfy one or more of the following characteristics:

[0210] The positive electrode interface functional layer exists, and σ1 is greater than σ. P and σ E At least one of them; alternatively, when σ1>σ P time f m1 <f mP When σ1>σ E time f m1 <f mE ;

[0211] The negative electrode interface functional layer exists, and σ² is greater than σ. N and σ E At least one of them; alternatively, when σ2>σ N time f m2 <f mN When σ² > σ E time f m2 <f mE .

[0212] In some implementations, solid-state batteries satisfy one or more of the following characteristics:

[0213] The positive electrode interface functional layer exists, and σ1 is greater than σ. P and σ E At least one of them; alternatively, f m1 <f mP And f m1 <f mE , σ1>σ P And σ1>σ E ;

[0214] The negative electrode interface functional layer exists, and σ² is greater than σ. N and σ E At least one of them; alternatively, f m2 <f mN And f m2 <f mE , σ2>σ N And σ² > σ E .

[0215] In some implementations, solid-state batteries satisfy one or more of the following characteristics:

[0216] The positive electrode interface functional layer exists, σ1>σ P And f m1 <f mP Or, σ1>σ E And f m1 <f mE ;

[0217] The negative electrode interface functional layer exists, σ2>σ N And f m2 <f mN Or, σ²>σ E And f m2 <f mE ;

[0218] The positive electrode interface functional layer exists, f m1 <f mP And f m1 <f mE , σ1>σ P And σ1>σ E ;

[0219] The negative electrode interface functional layer exists, f m2 <f mN And f m2 <f mE , σ2>σ N And σ² > σ E .

[0220] When a positive electrode interface functional layer is present, the conductivity σ1 of the positive electrode interface functional layer can be higher than the conductivity of at least one of the positive electrode active material layer and the solid electrolyte layer. Furthermore, by controlling the content f of organic components in the positive electrode interface functional layer... m1 By being lower than both the positive electrode active material layer and the solid electrolyte layer, the overall conductivity of the positive electrode interface functional layer can be higher than that of both the positive electrode layer and the solid electrolyte layer.

[0221] When the conductivity σ1 of the positive electrode interface functional layer is higher than the conductivity σ of the positive electrode active material layer P At that time, the mass percentage f of the organic components in the positive electrode interface functional layer can be set. m1 The mass percentage f of organic components in the positive electrode active material layer is lower than that of the positive electrode active material layer. mP .

[0222] When the conductivity σ1 of the positive electrode interface functional layer is higher than the conductivity σ of the solid electrolyte layer E At that time, the mass percentage f of the organic components in the positive electrode interface functional layer can be set. m1 The mass percentage f of organic components in the solid electrolyte layer mE .

[0223] When the negative electrode interface functional layer is present, the conductivity σ2 of the negative electrode interface functional layer can be higher than that of at least one of the negative electrode active material layer and the solid electrolyte layer. Furthermore, by controlling the content f of organic components in the negative electrode interface functional layer... m2 By being lower than both the negative electrode active material layer and the solid electrolyte layer, the overall conductivity of the negative electrode interface functional layer can be higher than that of both the negative electrode layer and the solid electrolyte layer.

[0224] When the conductivity σ2 of the negative electrode interface functional layer is higher than the conductivity σ of the negative electrode active material layer N At that time, the mass percentage f of the organic components in the negative electrode interface functional layer can be set. m2 The mass percentage f of organic components in the negative electrode active material layer is lower than that of the negative electrode active material layer. mN .

[0225] When the conductivity σ2 of the negative electrode interface functional layer is higher than the conductivity σ of the solid electrolyte layer E At that time, the mass percentage f of the organic components in the negative electrode interface functional layer can be set. m2 The mass percentage f of organic components in the solid electrolyte layer mE .

[0226] In some implementations, the interface functional layer satisfies one or both of the following characteristics:

[0227] At least a portion of the interface functional layer is an extension region of the adjacent electrode active material layer;

[0228] At least a portion of the interface functional layer is an extension region of the solid electrolyte layer.

[0229] In this application, unless otherwise specified, "at least a portion of the interface functional layer is an extension region of the adjacent electrode active material layer" means that at least a portion of the interface functional layer is continuously transitioned to the adjacent electrode active material layer. It can be considered that there is no identifiable interlayer interface between this portion of the interface functional layer and the adjacent electrode active material layer. For example, after etching the initial electrode active layer of the electrode sheet, when the interface functional layer is formed by combining the rough surface formed by the etching process with the solid electrolyte layer, the convex portion in the rough surface and the unetched portion originate from the same electrode sheet substrate. It can be considered that there is no identifiable interlayer interface between them. At this time, the portion of the interface functional layer corresponding to the convex portion is continuously transitioned to the unetched portion (the unetched portion can correspond to the electrode active material layer of the corresponding electrode layer in the solid-state battery cell), so that the portion of the interface functional layer corresponding to the convex portion constitutes an extension region of the electrode active material layer.

[0230] In this application, unless otherwise specified, "at least a portion of the interface functional layer is an extension region of the solid electrolyte layer" means that at least a portion of the interface functional layer and the solid electrolyte layer are in a continuous transition. It can be considered that there is no identifiable interlayer interface between this portion of the interface functional layer and the solid electrolyte layer. For example, after etching the solid electrolyte film, the protrusions in the rough surface formed by the etching process and the unetched portions originate from the same solid electrolyte film substrate. It can be considered that there is no identifiable interlayer interface between them. The portion of the interface functional layer corresponding to the protrusions is in a continuous transition with the unetched portion (the unetched portion can correspond to the corresponding solid electrolyte layer in the solid-state cell), so that the portion of the interface functional layer corresponding to the protrusions constitutes an extension region of the solid electrolyte layer.

[0231] When at least a portion of the interface functional layer is an extension region of the adjacent electrode active material layer, the interface functional layer provides better charge transfer, better ion conduction and electronic conduction, and has better interfacial adhesion and lower interfacial impedance with the adjacent electrode layer, which can significantly improve the cycle performance of the battery.

[0232] When at least a portion of the interfacial functional layer is an extension of the solid electrolyte layer, the interfacial functional layer provides better charge transfer, better ion conduction and electronic conduction, and has better interfacial adhesion and lower interfacial impedance with the solid electrolyte layer, which can significantly improve the cycle performance of the battery.

[0233] When at least a portion of the interface functional layer is an extension of the adjacent electrode active material layer and at least a portion of the interface functional layer is an extension of the solid electrolyte layer, the interface adhesion is better, the interface impedance is lower, and the improvement effect on battery performance is more significant, including at least the improvement on battery cycle performance.

[0234] In some embodiments, the interface functional layer includes an interface active material of the same type as the electrode active material in the adjacent electrode layer.

[0235] In some embodiments, the interface functional layer includes an interface layer electrolyte material of the same type as the solid electrolyte material in the solid electrolyte layer.

[0236] In some embodiments, the interface functional layer includes an interface layer active material of the same type as the electrode active material in the adjacent electrode layer, and also includes an interface layer electrolyte material of the same type as the solid electrolyte material in the solid electrolyte layer.

[0237] By setting the same type of electrode active material in the interface functional layer as in the electrode active material layer and the same type of solid electrolyte material in the solid electrolyte layer, the compatibility between the interface functional layer and the electrode layer and the solid electrolyte layer can be better improved, and the interfacial impedance between the electrode layer and the solid electrolyte layer can be reduced.

[0238] The interface functional layer connecting the electrode layer and the solid electrolyte layer can be formed using the in-situ method described in the second aspect of this application, but it is not limited to these methods.

[0239] In some implementations, the interface functional layer has overlapping interfaces.

[0240] As mentioned earlier, scanning electron microscopy (SEM) and computed tomography (CT) can be used to observe the microscopic morphology of the cross-section to confirm whether there are interlocking interfaces within the functional layers. This can also be used to analyze whether the first and second sublayers are present. Furthermore, elemental analysis methods can be combined to analyze the first and second sublayers. Without limitation, focused electron beam (FIB) serial slicing, cross-sectional SEM morphology observation, energy dispersive spectroscopy (EDS) elemental energy dispersive spectroscopy, and 3D reconstruction analysis software can be used to analyze the interface functions in solid-state batteries. For example, the nanoscale spatial dynamic resolution and layer-by-layer cutting technique of FIB-SEM can be used to reconstruct the three-dimensional structure of the sample, and EDS elemental energy dispersive spectroscopy analysis can be used to obtain the distribution of each element.

[0241] The interfacial functional layer has the characteristic of interfacial contact area, which can improve the interfacial connection and adhesion, and reduce the interfacial impedance. This helps to better layer-to-layer composite between the electrode layer and the solid electrolyte layer, and thus can better reduce the interfacial impedance between the electrode layer and the solid electrolyte layer.

[0242] In some implementations, each interface functional layer independently includes a first sublayer and a second sublayer, with the second sublayer located between the first sublayer and the solid electrolyte layer;

[0243] The first sublayer and the adjacent electrode layers contain the same type of electrode active material;

[0244] The second sublayer and the solid electrolyte layer both contain the same type of solid electrolyte material.

[0245] By setting a first sublayer with the same type of electrode active material as the electrode active material layer and a second sublayer with the same type of solid electrolyte material as the solid electrolyte layer in the interface functional layer, the compatibility between the interface functional layer and the electrode layer and the solid electrolyte layer can be better improved, the interfacial impedance between the electrode layer and the solid electrolyte layer can be reduced, and thus the aforementioned electrochemical performance of the battery can be better improved.

[0246] In some implementations, the positive electrode interface functional layer includes a first sub-layer and a second sub-layer.

[0247] In some implementations, the negative electrode interface functional layer includes a first sub-layer and a second sub-layer.

[0248] In some implementations, the mass percentage of the electrode active material in the first sublayer is higher than that in the second sublayer.

[0249] In some implementations, the mass percentage of solid electrolyte material in the second sublayer is higher than that in the first sublayer.

[0250] In some embodiments, the mass percentage of the electrode active material in the first sublayer is higher than that in the second sublayer; the mass percentage of the solid electrolyte material in the second sublayer is higher than that in the first sublayer.

[0251] By taking advantage of the fact that the content of electrode active material in the first sublayer is higher than that in the second sublayer, the mass ratio of electrode active material decreases sequentially from the corresponding electrode layer, the interface functional layer to the solid electrolyte layer. By taking advantage of the fact that the content of solid electrolyte material in the second sublayer is higher than that in the first sublayer, the mass ratio of solid electrolyte material increases sequentially from the solid electrolyte layer, the interface functional layer to the corresponding electrode layer. These characteristics are more conducive to reducing interfacial impedance.

[0252] In some implementations, there is an interlocking interface between the first sublayer and the second sublayer.

[0253] By interleaving the interfaces of the first and second sublayers, the interfacial contact area can be increased, which is beneficial to improving interfacial adhesion and bonding, and reducing interfacial impedance. This facilitates better layer-to-layer composite between the electrode layer and the solid electrolyte layer, thereby better reducing the interfacial impedance between the electrode layer and the solid electrolyte layer. This, in turn, can better improve the aforementioned electrochemical performance of the battery, including improving battery cycle performance, as well as improving discharge capacity and rate performance.

[0254] In some implementations, the first sublayer and the second sublayer are in contact with each other through an interlocking interface with a concave-convex shape.

[0255] In some embodiments, the solid-state battery includes a positive electrode layer, a solid electrolyte layer, a negative electrode interface functional layer, and a negative electrode layer stacked sequentially. The negative electrode interface functional layer includes a first sublayer and a second sublayer, with the first sublayer in contact with the negative electrode layer and the second sublayer in contact with the solid electrolyte layer. In this case, the solid-state battery includes a positive electrode layer, a solid electrolyte layer, a second sublayer, a first sublayer, and a negative electrode layer stacked sequentially.

[0256] In some embodiments, the solid-state battery includes a positive electrode layer, a positive electrode interface functional layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially. The positive electrode interface functional layer includes a first sublayer and a second sublayer, with the first sublayer in contact with the positive electrode layer and the second sublayer in contact with the solid electrolyte layer. In this case, the solid-state battery includes a positive electrode layer, a first sublayer, a second sublayer, a solid electrolyte layer, and a negative electrode layer stacked sequentially.

[0257] In some embodiments, the solid-state battery includes a positive electrode layer, a positive electrode interface functional layer, a solid electrolyte layer, a negative electrode interface functional layer, and a negative electrode layer stacked sequentially. The positive electrode interface functional layer and the interface functional layer each independently include a first sublayer and a second sublayer, and either second sublayer is in contact with the solid electrolyte layer.

[0258] In some embodiments, at least one of the positive electrode active material layer and the negative electrode active material layer includes an organic component;

[0259] The density of the solid electrolyte layer is denoted as K. E Satisfying K E ≥90%, K can be selected. E ≥97%. Without limitation, K E It can also be any of the following percentages or intervals composed of two percentages: 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, etc.

[0260] In some embodiments, at least one of the positive electrode active material layer and the negative electrode active material layer includes an organic component, which includes an organic binder.

[0261] In this application, unless otherwise specified, "density," also known as packing ratio or maximum space utilization, refers to the percentage of volume occupied by atoms themselves in a unit cell, that is, the ratio of the volume of atoms contained in the unit cell to the volume of the unit cell. "Density" can be used to characterize the compactness of atomic packing in a "structural layer." Unless otherwise specified, the density parameter K of the structural layer can be detected and analyzed using a true density meter (such as G-DenPyc 3900M). E .

[0262] When a solid electrolyte layer is prepared using a positive or negative electrode layer as a substrate, by controlling the presence of organic components in the positive or negative electrode active material layer, surface treatment can be used to remove organic binders and form exhaust microchannels. This is beneficial for improving the density during subsequent pressing treatments (such as warm isostatic pressing), thereby significantly improving the interfacial impedance within the solid electrolyte layer, and further enhancing the aforementioned electrochemical performance of the battery.

[0263] In some embodiments, the solid electrolyte layer includes an organic electrolyte component, and the solid-state battery satisfies at least one of the following characteristics:

[0264] (b1) Let the density of the cathode layer be denoted as K. P Satisfying K P ≥90%, K can be selected. P ≥97%;

[0265] (b2) Let the density of the negative electrode layer be denoted as K. N Satisfying K N ≥90%, K can be selected. N ≥97%.

[0266] In some embodiments, the solid electrolyte layer includes an electrolyte organic component, which may include one or more of an organic binder and an organic dispersant.

[0267] Without limitation, K P It can also be any of the following percentages or intervals composed of two percentages: 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, etc.

[0268] Without limitation, K N It can also be any of the following percentages or intervals composed of two percentages: 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, etc.

[0269] When a positive or negative electrode layer is prepared using a solid electrolyte layer as a substrate, by controlling the presence of organic components in the solid electrolyte layer, surface treatment can be used to remove organic binders and form exhaust microchannels, which is beneficial to improving the density during subsequent pressing treatment (such as warm isostatic pressing), thereby significantly improving the interfacial impedance within the positive or negative electrode layer, and further improving the aforementioned electrochemical performance of the battery.

[0270] In some implementations, the solid-state battery is an all-solid-state battery.

[0271] In this application, unless otherwise specified, "all-solid-state battery" refers to a solid-state battery in which all electrolytes are solid electrolytes. In this case, the positive electrode layer, negative electrode layer and electrolyte part are all made of solid materials, and no liquid electrolyte is provided in the battery, so it can be called "all-solid-state battery".

[0272] 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.

[0273] In this application, unless otherwise specified, "solid-state battery cell" refers to a basic unit capable of converting chemical energy into electrical energy, and all its components are solid-state. In some embodiments, a solid-state battery cell may be an all-solid-state battery cell.

[0274] In this application, unless otherwise specified, "all-solid-state battery cell" refers to a solid-state battery cell in which all electrolytes are solid electrolytes. In this case, the positive electrode layer, negative electrode layer and electrolyte part are all made of solid materials, and no liquid electrolyte is provided in the battery cell, so it can be called "all-solid-state battery cell".

[0275] Non-limitingly, a solid-state battery cell (which can be an all-solid-state battery cell) may include a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, with the solid electrolyte layer located between the positive and negative electrode layers. During battery charging and discharging, active ions shuttle between the positive and negative electrode layers, inserting and extracting. The solid electrolyte layer serves to conduct ions between the positive and negative electrode layers and also isolates them, thus preventing short circuits between the positive and negative electrodes.

[0276] In some embodiments, the solid-state battery cell 5 includes a solid-state cell 52.

[0277] In some implementations, the solid-state cell is an all-solid-state cell.

[0278] In some embodiments, the solid-state cell 52 (which may be an all-solid-state cell) includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially.

[0279] In some embodiments, the solid-state battery cell 52 (which may be an all-solid-state battery cell) includes a solid electrolyte layer 100 and electrode layers 120 located on both sides of the solid electrolyte layer. An interface functional layer 22 is provided between the solid electrolyte layer 100 and one of the electrode layers. Referring to FIG1, an interface functional layer 22 is provided between the solid electrolyte layer 100 and one of the electrode layers 120.

[0280] In some embodiments, the solid-state battery cell 52 (which can be an all-solid-state battery cell) includes a positive electrode layer 200, a positive electrode interface functional layer 222, a solid electrolyte layer 100, and a negative electrode layer 300 stacked sequentially. Referring to Figure 2, an interface functional layer is provided between the solid electrolyte layer and the positive electrode layer.

[0281] In some embodiments, the solid-state battery cell 52 (which may be an all-solid-state battery cell) includes a positive electrode layer 200, a solid electrolyte layer 100, a negative electrode interface functional layer 223, and a negative electrode layer 300 stacked sequentially. Referring to Figure 3, an interface functional layer is provided between the solid electrolyte layer and the negative electrode layer.

[0282] In some embodiments, the solid-state battery cell 52 (which can be an all-solid-state battery cell) includes a positive electrode layer 200, a positive electrode interface functional layer 222, a solid electrolyte layer 100, a negative electrode interface functional layer 223, and a negative electrode layer 300 stacked sequentially. Referring to Figure 4, interface functional layers are provided between the solid electrolyte layer and the positive electrode layer, as well as between the solid electrolyte layer and the negative electrode layer.

[0283] In some embodiments, the solid-state battery cell 52 (which can be an all-solid-state battery cell) includes a positive electrode layer 200, a solid electrolyte layer 100, a negative electrode interface functional layer 223, and a negative electrode layer 300 stacked sequentially. The negative electrode interface functional layer 223 includes a first sub-layer 201 and a second sub-layer 202, with the first sub-layer 201 in contact with the negative electrode layer 300 and the second sub-layer 202 in contact with the solid electrolyte layer 100. In this case, the solid-state battery cell 52 (which can be an all-solid-state battery cell) includes the positive electrode layer 200, the solid electrolyte layer 100, the second sub-layer 202, the first sub-layer 201, and the negative electrode layer 300 stacked sequentially. See Figure 5.

[0284] In some embodiments, the solid-state battery cell 52 (which can be an all-solid-state battery cell) includes a positive electrode layer 200, a positive electrode interface functional layer 222, a solid electrolyte layer 100, and a negative electrode layer 300 stacked sequentially. The positive electrode interface functional layer 222 includes a first sub-layer 201 and a second sub-layer 202, where the first sub-layer 201 is in contact with the positive electrode layer 200, and the second sub-layer 202 is in contact with the solid electrolyte layer 100. In this case, the solid-state battery cell 52 (which can be an all-solid-state battery cell) includes the positive electrode layer 200, the first sub-layer 201, the second sub-layer 202, the solid electrolyte layer 100, and the negative electrode layer 300 stacked sequentially. See Figure 6.

[0285] In this application, unless otherwise specified, "stacked arrangement" is used to describe the positional relationship of multiple layered structures, meaning that multiple layered structures are stacked along their respective thickness directions. Those skilled in the art will understand its meaning. For example, "including stacked structural layer A and structural layer B" means that the stacking direction of structural layer A and structural layer B is along their respective thickness directions; that is, the thickness direction of structural layer A and the thickness direction of structural layer B are consistent or substantially consistent. It is understood that other intermediate structural layers are permitted to be disposed between structural layer A and structural layer B.

[0286] The following is a description of the positive electrode layer.

[0287] The positive electrode layer can be formed based on an etched solid electrolyte membrane or provided by a pre-fabricated positive electrode sheet, which can be a positive electrode sheet that is suitable for solid-state batteries in the art. See the second aspect of this application.

[0288] Positive electrode sheets can be prepared using dry or wet methods. For example, they can be dry-pressed into films. Alternatively, they can be wet-coated and dried to form films.

[0289] In some embodiments, the positive electrode layer 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.

[0290] Unless otherwise stated, the positive electrode layer in this application includes at least a positive electrode active material layer.

[0291] In this application, unless otherwise specified, the positive electrode sheet includes at least a positive electrode active material layer. In some embodiments, the positive electrode sheet includes a positive electrode initial active layer, which, after etching, a portion of the positive electrode initial active layer participates in the formation of the positive electrode interface functional layer, while the remainder serves as the positive electrode active material layer.

[0292] In this application, unless otherwise specified, the positive electrode active material layer includes at least positive electrode active particles, and usually also includes positive electrode electrolyte particles.

[0293] In this application, unless otherwise specified, "positive electrode active particles" refers to particles containing positive electrode active substances that have the ability to reversibly extract and insert active ions.

[0294] In this application, unless otherwise specified, "positive electrode electrolyte particles" and "positive electrode solid electrolyte" have the same meaning and can be used interchangeably, referring to solid electrolytes that can be used in the positive electrode layer. Positive electrode electrolyte particles can enhance the ion conductivity of the positive electrode layer, reduce interfacial impedance, and promote the charge transfer efficiency and full release of capacity between the positive electrode active material and the external environment.

[0295] In some embodiments, the positive electrode active material may be a known positive electrode active material for batteries. As a non-limiting example, the positive electrode active material may include one or more of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and their modified compounds. Non-limiting examples of lithium-containing phosphates with an olivine structure include, but are not limited to, one or more of lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium manganese iron phosphate and carbon composites. Non-limiting examples of lithium cobalt oxides may include LiCoO2; non-limiting examples of lithium nickel oxides may include LiNiO2; non-limiting examples of lithium manganese oxides may include LiMnO2, LiMn2O4, etc.; non-limiting examples of lithium nickel cobalt manganese oxides may include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 Examples of lithium nickel cobalt aluminum oxides include LiNi, etc. 0.80 Co 0.15 Al 0.05 O2. Examples of lithium iron phosphate include LiFePO4 (also known as LFP). Examples of lithium manganese phosphate include LiMnPO4.

[0296] Without limitation, the weight percentage of positive electrode active particles or positive electrode active materials in the positive electrode active material layer can be ≥70wt%, further ≥80wt%, even further ≥90wt%, and can also be 70wt% to 99wt%, optionally 80wt% to 95wt%.

[0297] Non-limiting, the weight percentage of the positive electrode electrolyte particles in the positive electrode active material layer can be 0.1 wt% to 30 wt%, and optionally 5 wt% to 20 wt%.

[0298] In some embodiments, the positive electrode active material layer includes positive electrode electrolyte particles. Non-limitingly, the weight percentage of the positive electrode electrolyte particles in the positive electrode active material layer can be from 0.1 wt% to 30 wt%, optionally from 5 wt% to 20 wt%.

[0299] In some embodiments, the positive electrode active material layer includes positive electrode active particles and positive electrode electrolyte particles.

[0300] In some embodiments, the positive electrode active material layer includes a conductive agent (which may be referred to as a positive electrode conductive agent). As a non-limiting example, the positive electrode conductive agent may be a carbon conductive agent. Non-limitingly, the carbon conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the positive electrode conductive agent may include, but is not limited to, one or more of SP, KS-6, acetylene black, branched Ketjen black ECP, SFG-6, vapor-grown carbon fiber VGCF, carbon nanotubes (CNTs), and graphene. Non-limitingly, the weight percentage of the positive electrode conductive agent in the positive electrode active material layer may be 0–10 wt%, more further 0–8 wt%, even further 0–5 wt%, and even further 0.1 wt%–3 wt%. When the positive electrode material is prepared into a positive electrode active material layer using a dry method, the positive electrode conductive agent can be incorporated into the positive electrode material, which can improve the conductivity of the positive electrode active material layer.

[0301] 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), a terpolymer of PVDF-tetrafluoroethylene-propylene, a terpolymer of PVDF-hexafluoropropylene-tetrafluoroethylene, a tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins. The aforementioned non-limiting examples of positive electrode binders are all organic binders and belong to organic components. Typically, the weight percentage of the positive electrode binder in the positive electrode active material layer can be 0–10 wt%, more commonly 0–8 wt%, even more commonly 0.1 wt%–5 wt%, and even more commonly 1 wt%–5 wt%. When the positive electrode material is formulated into a positive electrode slurry using a wet process and then the positive electrode active material layer is prepared, the positive electrode binder can be placed in the positive electrode slurry, which can assist in film formation and also promote the formation of a good electrical contact network between the active particles in the positive electrode active material layer.

[0302] Non-limiting, the positive electrode active material layer may include positive electrode active particles, positive electrode electrolyte particles, positive electrode conductive agent, and positive electrode binder. The types and contents of each component can be found in the context of this application.

[0303] As a non-limiting example, the positive current collector has two surfaces that are opposite to each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0304] 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 substrate and a metal layer formed on at least one surface of the polymer material substrate. In the positive electrode current collector, the composite current collector may be obtained by forming a metal material on the polymer material substrate. Non-limiting examples of the metal material in the positive electrode current collector may include at least one of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. Non-limiting examples of the polymer material substrate in the positive electrode current collector may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0305] In some embodiments, the positive electrode sheet can be prepared by: dry mixing the components used to prepare the positive electrode sheet, such as positive electrode active particles, positive electrode electrolyte particles, positive electrode conductive agent, positive electrode binder, and any other components; then heating and pressurizing the mixed material to knead it into a clump; hot rolling pressing to form a self-supporting positive electrode sheet; and hot rolling bonding the self-supporting positive electrode sheet with a positive electrode current collector, wherein the self-supporting positive electrode sheet can be bonded to at least one side (single or double sides) of the positive electrode current collector to obtain the positive electrode sheet. Non-limitingly, a dual planetary mixer can be used for dry mixing. Non-limitingly, a kneading and pressing process can be performed using a Banbury mixer. Non-limitingly, the temperature for hot rolling pressing 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 using positive electrode sheets is suitable for industrial mass production.

[0306] In some embodiments, the positive electrode sheet can be prepared by dispersing the components used to prepare the positive electrode sheet, such as positive electrode active particles, positive electrode electrolyte particles, positive electrode conductive agent, positive electrode binder, and any other components, in an organic solvent to form a positive electrode slurry. Further, the positive electrode slurry is coated onto at least one surface of the positive electrode current collector, and after drying, cold pressing, and other processes, the positive electrode sheet is obtained. Cold pressing can be performed using a cold rolling mill. Non-limitingly, the organic solvent in the positive electrode slurry can include one or more of p-xylene, trimethylbenzene, butyl butyrate, heptane, etc., and more specifically, 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 coating the positive electrode slurry, the coating density per unit area, measured by dry weight (excluding solvent), can be 15 mg / cm³, based on the amount coated on one side of the positive electrode current collector. 2 ~35mg / cm 2 However, this is not the only possibility. The compaction density of the positive electrode sheet can be 3.0 g / cm³. 3 ~3.6g / cm 3 3.3g / cm³ is an option. 3 ~3.5g / cm 3 .

[0307] The term "compacted density" as used in this application has a meaning known in the art and is one of the reference indicators for 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 the positive electrode layer or positive electrode sheet refers to the ratio of the mass of the positive electrode active material layer to its volume, and the compacted density of the negative electrode layer or negative electrode sheet refers to the ratio of the mass of the negative electrode active material layer to its volume.

[0308] The following is a description of the negative electrode layer.

[0309] The negative electrode layer can be formed based on an etched solid electrolyte membrane or provided by a pre-fabricated negative electrode sheet, which can be a negative electrode sheet that is suitable for solid-state batteries in the art. See the second aspect of this application.

[0310] The negative electrode sheet can be prepared by dry or wet methods. For example, it can be formed into a film by dry pressing. Alternatively, it can be formed into a film by wet coating.

[0311] In this application, unless otherwise specified, the negative electrode layer includes at least a negative electrode active material layer.

[0312] In this application, unless otherwise specified, the negative electrode sheet includes at least a negative electrode active material layer. In some embodiments, the negative electrode sheet includes a negative electrode initial active layer, which, after etching, a portion of the negative electrode initial active layer participates in forming the negative electrode interface functional layer, while the remainder serves as the negative electrode active material layer.

[0313] Unless otherwise stated in this application, the negative electrode active material layer includes at least negative electrode active particles.

[0314] Without limitation, the negative electrode active material layer may include a solid electrolyte. The solid electrolyte in the negative electrode active material layer may be referred to as "negative electrode electrolyte particles".

[0315] In this application, unless otherwise specified, "negative electrode electrolyte particles" refers to solid electrolytes that can be used in the negative electrode layer. Negative electrode electrolyte particles can enhance the ion conductivity of the negative electrode layer, reduce interfacial impedance, and promote the charge transfer efficiency and full release of the capacity of the negative electrode active material with the external environment.

[0316] In this application, unless otherwise specified, "negative electrode active particles" refers to particles containing negative electrode active substances that have the ability to reversibly insert and extract active ions.

[0317] In some embodiments, the negative electrode sheet includes a negative electrode active material layer, the negative electrode active material layer includes negative electrode active particles, and the negative electrode active particles contain negative electrode active substances.

[0318] Without limitation, the weight percentage of negative electrode active particles or negative electrode active materials in the negative electrode active material layer can be ≥80wt%, and more preferably ≥90wt%.

[0319] Non-limiting, the weight percentage of the negative electrode electrolyte particles in the negative electrode active material layer can be 0 to 30 wt%, preferably 0.1 wt% to 30 wt%, and further preferably 5 wt% to 20 wt%.

[0320] In some embodiments, the negative electrode active particles or negative electrode active material are lithium indium alloys (InLi alloys).

[0321] In some implementations, the negative electrode layer or negative electrode sheet is an InLi alloy film.

[0322] In some embodiments, the negative electrode active material may also be a negative electrode active material known in the art for use in 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 anode, silicon suboxide, graphite, and metallic lithium. However, this application is not limited to these materials or substances, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0323] In some embodiments, the negative electrode sheet 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 comprising a negative electrode active substance. As a non-limiting example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite 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 the 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 polymeric material substrate may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0324] In some embodiments, the negative electrode active material layer optionally includes a conductive agent (which may be referred to as a negative electrode conductive agent). Non-limitingly, the negative electrode conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. Non-limitingly, the weight percentage of the negative electrode conductive agent in the negative electrode active material layer may be 0–15 wt%, more preferably 0–10 wt%, and even more preferably 0–5 wt%.

[0325] In some embodiments, the negative electrode active material layer optionally includes a binder (denoted as negative electrode binder). As a non-limiting example, the negative electrode binder may include one or more of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS). Non-limitingly, the weight percentage of the negative electrode binder in the negative electrode active material layer may be 0–10 wt%, more preferably 0–5 wt%, even more preferably 1 wt%–5 wt%, and even more preferably 1 wt%–3 wt%.

[0326] In some embodiments, the negative electrode active material layer may optionally include other additives, such as thickeners (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%, more preferably 0–10 wt%, even more preferably 0–5 wt%, even more preferably 0–3 wt%, and even more preferably 0–2 wt%.

[0327] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as negative electrode active particles, negative electrode conductive agent, negative electrode binder, and any other components, in a solvent (a non-limiting example of a solvent is p-xylene) to form a negative electrode slurry. Further, the negative electrode slurry is coated onto at least one surface of the negative electrode current collector, and after drying, cold pressing, and other processes, the negative electrode sheet is obtained. Cold pressing can be performed using a cold rolling mill. The surface of the negative electrode current collector coated with the negative electrode slurry can be a single surface of the negative electrode current collector or both surfaces of the negative electrode current collector. The solid content of the negative electrode slurry can be 30wt% to 70wt%, optionally 40wt% to 60wt%. The viscosity of the negative electrode slurry at room temperature can be adjusted to 2000 mPa·s to 10000 mPa·s, optionally 3000 mPa·s to 10000 mPa·s. When coating the negative electrode slurry, the coating density per unit area, based on the amount coated on one side of the negative electrode current collector and calculated by dry weight (excluding solvent), can be 1.5 mg / cm³. 2 ~22mg / cm 2 However, this is not the only possibility. The compaction density of the negative electrode sheet can be 1.0 g / cm³. 3 ~2.0g / cm 3 1.0g / cm³ is an optional value. 3 ~1.8g / cm 3 .

[0328] The following is a description of the solid electrolyte layer.

[0329] A solid electrolyte layer can be introduced by forming electrode layers on both sides of the solid electrolyte membrane, or it can be introduced on the electrode layer.

[0330] The solid electrolyte layer acts as a conductor of ions between the positive and negative electrode layers, and can also isolate the positive and negative electrode layers to prevent short circuits between them.

[0331] It is understood that the solid electrolyte layer includes a solid electrolyte. The solid electrolyte in the solid electrolyte layer can be a solid electrolyte known in the art that can be used in solid-state batteries.

[0332] The types of solid electrolytes present in different film layers of a solid-state battery can be the same or different. For example, the solid electrolytes in the positive electrode electrolyte particles and the solid electrolyte layer can be the same or different.

[0333] As a non-limiting example, a solid electrolyte may independently include one or more of the following materials: sulfide solid electrolytes, halide solid electrolytes, oxide solid electrolytes, polymer solid electrolytes, etc.

[0334] As another non-limiting example, the solid electrolyte may independently include, but is not limited to, one or more of oxide-based solid electrolytes, sulfide-based solid electrolytes, and halide-based solid electrolytes. In some embodiments, the solid electrolyte may independently include, but is not limited to, one or more of Argyrodite-type sulfide electrolytes and halide electrolytes. Non-limiting examples of oxide-based solid electrolytes may include LISICON-type oxide electrolytes (such as γ-Li3PO4), 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, etc.) 3x La 2 / 3-x One or more of the following: TiO3, etc., 0≤x≤0.5, etc. Non-limiting examples of sulfide solid electrolytes may include Li... 10 GeP2S 12 Li₂S-P₂S₅, Argyrodite type (such as Li₆PS₅Cl, Li 5.5 PS 5.5 Cl 1.5One or more of the following (etc.). Non-limiting examples of halide solid electrolytes may include one or more of the following: Li3InCl6, Li3YCl6, Li3ScCl6, Li3ErCl6, Li2ZrCl6, etc.

[0335] Solid electrolyte membranes or solid electrolyte layers can be prepared using dry methods. In some embodiments, the solid electrolyte layer can be formed by pressing solid electrolyte materials into a solid electrolyte membrane. In other embodiments, the solid electrolyte layer is formed by pressing the constituent raw materials of the solid electrolyte layer onto an electrode layer. In still other embodiments, the solid electrolyte membrane can also be prepared using methods such as fibrosis combined with calendering, melt extrusion, or spraying.

[0336] Solid electrolyte layers can also be prepared using a wet process. The electrolyte slurry used includes at least a solid electrolyte and an organic solvent, and usually also includes one or more of a binder and a dispersant.

[0337] In some embodiments, the solid electrolyte layer may be formed based on an etched positive electrode. See also the second aspect of this application.

[0338] In some embodiments, the solid electrolyte layer may be formed based on an etched negative electrode. See the second aspect of this application.

[0339] In some embodiments, the thickness of the solid electrolyte layer can be 0.1 μm to 1000 μm, and can be selected as 10 μm to 100 μm, 100 μm to 800 μm, 500 μm to 800 μm, etc.

[0340] In some embodiments, the solid-state battery may include an outer packaging. This outer packaging can be used to encapsulate the aforementioned solid-state battery cell.

[0341] In some embodiments, the outer packaging of a solid-state battery can be a rigid shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of a solid-state battery can also be a soft pack, such as a pouch-type soft pack. The material of the soft pack can be plastic; further, non-limiting examples of plastics may include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0342] This application does not impose any particular limitation on the shape of the solid-state battery cell; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 9 shows a square solid-state battery cell 5 as an example.

[0343] In some embodiments, referring to FIG10, the outer packaging may include a housing 51 and a cover plate 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be placed over the opening to close the receiving cavity. A solid-state battery cell 52 is encapsulated within the receiving cavity. The number of solid-state battery cells 52 contained in the solid-state battery cell 5 may be one or more, which can be selected by those skilled in the art according to actual needs.

[0344] The solid-state battery can be either battery module 4 or battery pack 1.

[0345] The battery module includes at least one solid-state battery cell. The number of solid-state battery cells 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.

[0346] Figure 11 shows a battery module 4 as an example. Referring to Figure 11, in the battery module 4, multiple solid-state battery cells 5 can be arranged sequentially along the length of the battery module 4. Of course, they can also be arranged in any other arbitrary way. Furthermore, the multiple solid-state battery cells 5 can be fixed in place by fasteners.

[0347] Optionally, the battery module 4 may also include a housing with a receiving space in which multiple solid-state battery cells 5 are housed.

[0348] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the battery pack may contain one or more battery modules. Those skilled in the art can select an appropriate number based on the application and capacity of the battery pack.

[0349] Figures 12 and 13 show a battery pack 1 as an example. Referring to Figures 12 and 13, the battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box includes an upper box 2 and a lower box 3, the upper box 2 covering the lower box 3 to form a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0350] In a second aspect of this application, some methods for preparing solid-state batteries are provided.

[0351] These methods are in-situ methods for forming interfacial functional layers. Based on an etched surface, adjacent structural layers are introduced, ensuring that at least a portion of the interfacial functional layer has no identifiable interlayer interface with the adjacent structural layer, instead exhibiting a continuous interlayer transition. This also improves interfacial adhesion and reduces interfacial impedance between the structural layers on either side of the functional layer, thereby improving battery performance, including but not limited to cycle performance; for example, it can also improve discharge capacity and rate performance. Depending on the location of the interfacial functional layer, there may be no identifiable interlayer interface between at least a portion of the functional layer and the adjacent structural layer, or there may be no identifiable interlayer interface between at least a portion of the functional layer and the solid electrolyte layer; both of these scenarios are also permissible.

[0352] Compared to non-in-situ methods that introduce an intermediate functional layer with the same or similar components as the interface functional layer by wet coating between the electrode layer and the solid electrolyte layer, the in-situ method provided in the second aspect of this application is advantageous for achieving better interfacial adhesion, lower interfacial impedance, and better structural stability, thereby facilitating significantly better battery performance, including significantly better battery cycle performance, and also significantly better discharge capacity and rate performance. A non-limiting example of the non-in-situ method is as follows: dispersing the components of the intermediate functional layer, which are the same or similar to the interface functional layer, in an organic solvent to form an intermediate functional layer slurry; coating the intermediate functional layer slurry onto an unetched surface; drying; and then introducing the corresponding structural layer film by dry or wet methods, followed by cold pressing to form the intermediate functional layer and adjacent structural layers.

[0353] Using this in-situ method for forming the interface functional layer, the interface functional layer can satisfy one or two of the following characteristics:

[0354] At least a portion of the interface functional layer is an extension region of the adjacent electrode active material layer (at this time, there is no identifiable interlayer interface between this part of the interface functional layer and the adjacent electrode active material layer).

[0355] At least a portion of the interface functional layer is an extension region of the solid electrolyte layer (at this time, there is no identifiable interlayer interface between this part of the interface functional layer and the solid electrolyte layer).

[0356] The definitions of "at least a portion of the interface functional layer is an extension region of the adjacent electrode active material layer" and "at least a portion of the interface functional layer is an extension region of the solid electrolyte layer" can be found in the preceding text.

[0357] When at least a portion of the interface functional layer is an extension region of the adjacent electrode active material layer, the interface functional layer provides better charge transfer, better ion conduction and electronic conduction, and has better interfacial adhesion and lower interfacial impedance with the adjacent electrode layer, which can significantly improve the cycle performance of the battery.

[0358] When at least a portion of the interfacial functional layer is an extension of the solid electrolyte layer, the interfacial functional layer provides better charge transfer, better ion conduction and electronic conduction, and has better interfacial adhesion and lower interfacial impedance with the solid electrolyte layer, which can significantly improve the cycle performance of the battery.

[0359] When at least a portion of the interface functional layer is an extension of the adjacent electrode active material layer and at least a portion of the interface functional layer is an extension of the solid electrolyte layer, the interface adhesion is better, the interface impedance is lower, and the improvement effect on battery performance is more significant, including at least the improvement on battery cycle performance.

[0360] In some embodiments, a method for preparing a solid-state battery is provided, which includes the following steps:

[0361] S10: The electrode active initial layer located on at least one side surface of the electrode sheet is etched to form a rough surface with an electrode recess. The etched electrode sheet includes an electrode protrusion corresponding to the electrode recess. The electrode active initial layer includes degradable organic components. After etching, the content of degradable organic components in the electrode protrusion decreases.

[0362] S20: An electrolyte pre-coating is provided on a rough surface with an electrode recess. The electrolyte pre-coating is pressed so that the electrode protrusion and the portion of the electrolyte pre-coating filling the corresponding electrode recess together form an interface functional layer, and the remaining portion of the electrolyte pre-coating forms a solid electrolyte layer. The remaining portion of the electrode active initial layer is an electrode active material layer.

[0363] S30: An electrode layer is formed on the surface of the solid electrolyte layer away from the interfacial functional layer.

[0364] It can be understood that the electrode sheet in step S10 and the electrode layer in step S30 correspond to the positive electrode and the negative electrode, respectively.

[0365] In step S10, after etching, the portion of the initial electrode active layer excluding the portion forming the electrode protrusion is the electrode active material layer. In other words, the electrode active material layer corresponds to the unetched portion of the initial electrode active layer. When the electrode is a negative electrode, the initial electrode active layer and the electrode active material layer are both negative electrode active materials. When the electrode is a positive electrode, the initial electrode active layer and the electrode active material layer are both positive electrode active materials.

[0366] In step S10, the "rough surface with electrode recess" formed in the electrode sheet can also be referred to as "electrode rough surface". It can be understood that the electrode rough surface formed based on the negative electrode sheet can also be referred to as the negative electrode rough surface, and the electrode rough surface formed based on the positive electrode sheet can also be referred to as the positive electrode rough surface.

[0367] In step S10, after etching, the content of degradable organic components in the electrode protrusion decreases, while the content of degradable organic components in the electrode active material layer remains unchanged, resulting in the organic component content in the formed interface functional layer being lower than the organic component content in the electrode active material layer.

[0368] In this application, unless otherwise specified, in step S20, "the remaining portion of the electrolyte pre-coating" refers to the portion of the electrolyte pre-coating that is not filled in the electrode recess. Unless otherwise specified, it can be understood as the portion of the electrolyte pre-coating that is not in contact with the electrode rough surface (the "rough surface with electrode recess" formed in the electrode sheet) in the thickness direction.

[0369] By etching the surface of the electrode, degradable organic components are partially or completely removed, reducing the organic component content. On the one hand, the decrease in organic component content leads to an increase in the inorganic component content in the etched area of ​​the electrode surface, thereby improving the conductivity of the electrode surface, reducing interfacial impedance, and improving the electrochemical performance of the battery, including cycle performance. In addition, it is also beneficial to improve discharge capacity and rate performance. On the other hand, a rough surface with electrode recesses can be formed on the electrode surface. When further preparing the solid electrolyte layer, the formed solid electrolyte layer and the rough surface can form ventable microchannels. During subsequent pressing processes (such as warm isostatic pressing), these microchannels can be used to vent, increasing the pressing degree of the solid electrolyte layer and improving the density of the formed solid electrolyte layer. In addition, the rough surface can also increase the contact area between the solid electrolyte layer and the solid electrolyte layer, which is also beneficial to reducing interfacial impedance and thus improving battery performance, including at least improving battery cycle performance.

[0370] In some embodiments, the electrode sheet includes a current collector and an initial electrode active layer located on at least one side of the current collector.

[0371] In some embodiments, the electrode 12 includes a current collector 121 and an initial electrode activity layer 122 located on at least one surface of the current collector 121. The initial electrode activity layer may be located on one or both sides of the current collector. FIG7 provides a non-limiting example of an electrode 12 including a current collector 121 and an initial electrode activity layer 122 located on one surface of the current collector 121.

[0372] In this application, unless otherwise stated, "degradable organic component" refers to an organic component that can be selectively degraded and removed by surface treatment techniques available in the field of solid-state batteries, such as organic components that can be degraded and removed by etching treatment, and non-limiting examples of etching techniques such as one or more of plasma treatment and laser treatment.

[0373] Unless otherwise specified in this application, the following method can be used to determine whether "a substance or substances belong to degradable organic components": Substances that meet any of the following test results can be included in the category of degradable organic components:

[0374] Test Method 1: Substances that can be degraded by plasma treatment in the presence of oxygen, with an etching power of at least one power from 3kW to 10kW; plasma treatment may include at least oxygen plasma treatment, and see also the oxygen plasma treatment conditions below;

[0375] Test Method 2: Substances that can be degraded by laser treatment with wavelengths from 0.75μm to 14μm (e.g., 3μm to 5μm), with an etching power of at least one of 5kW to 20kW; see also the laser treatment conditions below.

[0376] Methods for identifying whether a substance has degraded are readily available to those skilled in the art. For example, degradation can be determined by changes in molecular weight; a decrease in molecular weight indicates degradation. Alternatively, changes in the structure of the components, or changes in the types of substances before and after the test, can also indicate degradation. Typically, degradation reactions result in the formation of new substances with smaller molecular weights due to the breaking of chemical bonds. Testing and analysis can be performed using one or more methods, including but not limited to: Fourier transform infrared (FT-IR) spectroscopy, ultraviolet spectroscopy, and proton nuclear magnetic resonance (NMR) spectroscopy. 1 Methods include 1H NMR, X-ray diffraction (XRD), gel permeation chromatography (GPC), high performance liquid chromatography (HPLC), and mass spectrometry. The sample preparation and testing methods for these methods are known to those skilled in the art, and the test parameters can be appropriately adjusted according to the characteristics of the analyte sample.

[0377] In this application, unless otherwise specified, the following substances are classified as "degradable organic components": organic binders, organic dispersants, etc. Non-limiting examples of organic binders may include one or more of polyvinylidene fluoride, styrene-butadiene rubber latex, carboxymethyl cellulose, sodium carboxymethyl cellulose, sodium alginate, polyvinyl alcohol, polymethyl methacrylate, hydrogenated nitrile butadiene rubber, polytetrafluoroethylene, polyacrylic acid, etc.; non-limiting examples of organic dispersants may include one or more of cationic wetting and dispersing agents, anionic wetting and dispersing agents, and amphoteric wetting and dispersing agents; wherein, cationic wetting and dispersing agents may include, but are not limited to, one or more of amine salts, quaternary ammonium salts, and pyridinium salts; anionic wetting and dispersing agents may include, but are not limited to, one or more of fatty acid salts, sulfate ester salts, and sulfonates; amphoteric wetting and dispersing agents may include, but are not limited to, phosphate ester salt-type polymers. Non-limiting examples of fatty acid salts include sodium oleate. Among them, the following substances were confirmed to be degradable using both Test Method 1 and Test Method 2: dodecyl fatty amine, hexadecylpyridinium chloride, sodium oleate, sodium dodecyl sulfate, sodium hexadecyl sulfonate, and polyethylene glycol monooleate, etc.

[0378] Unless otherwise specified in this application, the types and contents of "degradable organic components" in the "interface functional layer," "positive electrode layer," and "negative electrode layer" may be analyzed by one or more methods including but not limited to: Fourier transform infrared (FT-IR) spectroscopy, ultraviolet spectroscopy, and proton nuclear magnetic resonance (NMR) spectroscopy. 1 Methods include ¹H NMR, X-ray diffraction (XRD), gel permeation chromatography (GPC), high-performance liquid chromatography (HPLC), and mass spectrometry. Materials from corresponding structural layers can be extracted from electrodes disassembled from batteries for testing, or materials in the active electrode material layers of electrode sheets that have not yet been assembled into a battery can be tested. The battery under test can be a pre-fabricated battery that has not yet been used, or one that has not been discharged or charged / discharge cycled. Alternatively, the battery can be a pre-fabricated battery that has undergone discharge or charge / discharge cycles.

[0379] In some embodiments, a method for preparing a solid-state battery is provided, which includes the following steps:

[0380] S310: The initial active layer of the negative electrode located on at least one side surface of the negative electrode sheet is etched to form a rough surface of the negative electrode with a negative electrode recess. The negative electrode sheet after etching includes a negative electrode protrusion corresponding to the negative electrode recess. The initial active layer of the negative electrode includes degradable organic components. After etching, the content of degradable organic components in the negative electrode protrusion decreases.

[0381] S320: An electrolyte pre-coating is provided on the rough surface of the negative electrode. The electrolyte pre-coating is pressed so that the negative electrode protrusion and the portion of the electrolyte pre-coating filled in the corresponding negative electrode recess together form a negative electrode interface functional layer, and the remaining portion of the electrolyte pre-coating forms a solid electrolyte layer.

[0382] S330: A positive electrode layer is formed on the surface of the solid electrolyte layer away from the negative electrode interface functional layer.

[0383] After the etching process in step S310, the unetched portion of the negative electrode sheet can form the negative electrode layer in the prepared solid-state battery.

[0384] In step S310, the portion of the initial negative electrode active layer excluding the portion forming the negative electrode protrusion is used as the negative electrode active material layer, corresponding to the unetched portion of the initial negative electrode active layer.

[0385] In step S320, "the remainder of the electrolyte pre-coating" has the same meaning as in step S20 above.

[0386] In some embodiments, the negative electrode includes a negative current collector and a negative active initial layer located on at least one side of the negative current collector.

[0387] In some embodiments, the negative electrode 30 includes a negative electrode current collector 310 and a negative electrode active initial layer 32 located on at least one surface of the negative electrode current collector 310. The negative electrode active initial layer 32 may be located on one or both sides of the negative electrode current collector 310. In the solid-state battery fabrication method illustrated in FIG8, the negative electrode 30 used includes a negative electrode current collector 310 and a negative electrode active initial layer 32 located on one surface of the negative electrode current collector 310. In some embodiments, in the solid-state battery 52 obtained, the negative electrode current collector 310 and the negative electrode active material layer 320 together constitute the negative electrode layer 300.

[0388] A solid electrolyte layer and a positive electrode layer can be sequentially prepared on a negative electrode sheet containing a biodegradable organic component as the initial active layer. By etching the initial active layer on the surface of the negative electrode sheet, the biodegradable organic component is partially or completely removed, reducing the organic component content. On the one hand, the decrease in organic component content can lead to an increase in the inorganic component content in the etched area on the negative electrode surface, thereby improving the conductivity of the negative electrode surface, reducing interfacial impedance, and improving the battery's electrochemical performance, including cycle performance. In addition, it is also beneficial to improve discharge capacity and rate performance. On the other hand, a negative electrode rough surface with a negative electrode recess can be formed on the negative electrode surface. When further preparing the solid electrolyte layer, a ventable microchannel can be formed between the formed solid electrolyte layer and the negative electrode rough surface. During subsequent pressing processes (such as warm isostatic pressing), these microchannels can be used to vent, increasing the pressing degree of the solid electrolyte layer and improving the density of the formed solid electrolyte layer. In addition, the negative electrode rough surface can also increase the contact area between the solid electrolyte layer and the solid electrolyte layer, which is also beneficial to reducing interfacial impedance and thus improving battery performance, including at least improving battery cycle performance.

[0389] Please refer to Figure 8 for a schematic flowchart of the solid-state battery fabrication method. This fabrication method includes the following steps:

[0390] S310: Provides a negative electrode 30, which includes a negative current collector 310 and a negative active initial layer 32 located on one side surface of the negative current collector 310.

[0391] The initial active layer 32 of the negative electrode is etched to form a rough surface of the negative electrode with a negative electrode recess 332. The negative electrode sheet after etching includes a negative electrode protrusion 330 corresponding to the negative electrode recess 332 and a negative electrode active material layer 320 that has not been etched. The initial active layer 32 of the negative electrode includes biodegradable organic components. After etching, the content of biodegradable organic components in the negative electrode protrusion 330 decreases.

[0392] S322: An electrolyte pre-coating 110 is provided on the rough surface of the negative electrode;

[0393] S324: The electrolyte pre-coating 110 is pressed so that the negative electrode protrusion 330 and the electrolyte pre-coating portion filled in the corresponding negative electrode recess 332 together form the negative electrode interface functional layer 223, and the remaining portion of the electrolyte pre-coating forms the solid electrolyte layer 100; in this process, the negative electrode protrusion 330 forms the first sub-layer 201, and the electrolyte pre-coating portion at the negative electrode recess 332 forms the second sub-layer 202; the negative electrode interface functional layer 223 includes the first sub-layer 201 and the second sub-layer 202.

[0394] S330: A positive electrode layer 200 is formed on the surface of the solid electrolyte layer 100 away from the negative electrode interface functional layer 223.

[0395] In some embodiments, when a solid electrolyte layer is formed based on an etched negative electrode sheet, the density of the solid electrolyte layer is denoted as K. E Satisfying K E ≥90%, etching depth of 1μm~50μm; optionally, K E ≥97%, with an etching depth of 3μm~40μm.

[0396] By controlling the etching depth of the negative electrode sheet, the roughness of the negative electrode surface can be adjusted, thereby regulating the size of the ventable microchannels and resulting in a higher density of the solid electrolyte layer formed based on the etched negative electrode sheet. Furthermore, it allows for more complete interlocking of materials at the interface, which also contributes to improving the density of the solid electrolyte layer. Specifically, controlling the etching depth to 3μm–40μm is more conducive to providing appropriately sized ventable microchannels and promoting more complete interlocking of interface materials, further enhancing the density of the solid electrolyte layer.

[0397] In this application, unless otherwise specified, the etching depth can be controlled by controlling one or more parameters such as etching time, etching power, and number of etching processes. See also the more detailed description below.

[0398] It is understood that the etching depth does not exceed the initial thickness of the substrate being etched. In some embodiments, the etching depth is less than or equal to 60% of the initial thickness, optionally less than or equal to 50% of the initial thickness, and further optionally 0.5% to 50% of the initial thickness. Non-limitingly, the percentage of etching depth relative to the initial thickness may also be any of the following percentages or a range selected from any two of the following percentages: 0.5%, 1%, 2%, 4%, 5%, 6%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, etc.

[0399] In this application, when controlling the etching depth to be 1 μm to 50 μm, it can further be any of the following etching depths, or an interval consisting of any two of the following etching depths: 1 μm, 1.2 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.8 μm, 2 μm, 2.2 μm, 2.4 μm, 2.5 μm, 2.6 μm, 2.8 μm, 3 μm, 4 μm, 5 μm, 6 μm, 8 μm , 10μm, 12μm, 14μm, 15μm, 16μm, 18μm, 20μm, 22μm, 24μm, 25μm, 26μm, 28μm, 30μm, 32μm, 34 μm, 35μm, 36μm, 38μm, 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, etc.

[0400] In this application, when the etching depth is 3μm to 40μm, it can be any of the following etching depths, or it can be a range consisting of any two of the following etching depths: 3μm, 4μm, 5μm, 6μm, 8μm, 10μm, 12μm, 14μm, 15μm, 16μm, 18μm, 20μm, 22μm, 24μm, 25μm, 26μm, 28μm, 30μm, 32μm, 34μm, 35μm, 36μm, 38μm, 40μm, etc.

[0401] Non-limitingly, the etching depth can be determined by cross-sectional observation of the etched sample using a scanning electron microscope (SEM).

[0402] In some embodiments, a method for preparing a solid-state battery is provided, which includes the following steps:

[0403] S210: The positive electrode active initial layer located on at least one side surface of the positive electrode sheet is etched to form a positive electrode rough surface with a positive electrode recess, and the positive electrode sheet after etching includes a positive electrode protrusion corresponding to the positive electrode recess; wherein, the positive electrode active initial layer includes degradable organic components; after etching, the content of degradable organic components in the positive electrode protrusion decreases.

[0404] S220: An electrolyte pre-coating is provided on the rough surface of the positive electrode. The electrolyte pre-coating is pressed so that the positive electrode protrusion and the portion of the electrolyte pre-coating filled in the corresponding positive electrode recess together form a positive electrode interface functional layer, and the remaining portion of the electrolyte pre-coating forms a solid electrolyte layer.

[0405] S230: A negative electrode layer is formed on the surface of the solid electrolyte layer away from the positive electrode interface functional layer.

[0406] After the etching process in step S210, the unetched portion of the positive electrode sheet can form the positive electrode layer in the prepared solid-state battery.

[0407] In step S210, the portion of the initial positive electrode active layer excluding the portion forming the positive electrode protrusion is the positive electrode active material layer, corresponding to the unetched portion of the initial positive electrode active layer.

[0408] In step S220, "the remainder of the electrolyte pre-coating" has the same meaning as in the aforementioned step S20.

[0409] In some embodiments, the positive electrode is a self-supporting positive electrode composed of a positive active initial layer, that is, the positive electrode is a positive active initial layer film.

[0410] In some embodiments, the positive electrode includes a positive current collector and a positive active initial layer located on at least one side of the positive current collector.

[0411] In some embodiments, the positive electrode includes a positive current collector and a positive active initial layer located on at least one surface of the positive current collector. The positive active initial layer may be located on one or both sides of the positive current collector. In some embodiments of the solid-state battery fabrication method, the positive electrode used includes a positive current collector and a positive active initial layer located on one surface of the positive current collector. In some embodiments, in the fabricated solid-state battery, the positive current collector and the positive active material layer together constitute the positive electrode layer.

[0412] A solid electrolyte layer and a positive electrode layer can be sequentially prepared on a positive electrode sheet containing a biodegradable organic component as the initial active layer. By etching the initial active layer on the surface of the positive electrode sheet, the biodegradable organic component is partially or completely removed, reducing the organic component content. On the one hand, the decrease in organic component content can lead to an increase in the inorganic component content in the etched area on the positive electrode surface, thereby improving the conductivity of the positive electrode surface, reducing interfacial impedance, and improving the battery's electrochemical performance, including cycle performance. In addition, it is also beneficial to improve discharge capacity and rate performance. On the other hand, a positive electrode rough surface with a positive electrode recess can be formed on the positive electrode surface. When further preparing the solid electrolyte layer, a ventable microchannel can be formed between the formed solid electrolyte layer and the positive electrode rough surface. During subsequent pressing processes (such as warm isostatic pressing), these microchannels can be used to vent, increasing the pressing degree of the solid electrolyte layer and improving the density of the formed solid electrolyte layer. In addition, the positive electrode rough surface can also increase the contact area between the solid electrolyte layer and the solid electrolyte layer, which is also beneficial to reducing interfacial impedance and thus improving battery performance, including at least improving battery cycle performance.

[0413] In some embodiments, when a solid electrolyte layer is formed based on an etched positive electrode, the density of the solid electrolyte layer is denoted as K. E Satisfying K E ≥90%, etching depth of 1μm~50μm; optionally, K E ≥97%, with an etching depth of 3μm~40μm.

[0414] By controlling the etching depth of the positive electrode, the roughness of the positive electrode surface can be adjusted, allowing the ventable microchannels to have suitable dimensions. This results in a higher density of the solid electrolyte layer formed based on the etched positive electrode. Furthermore, it allows for more complete interlocking of materials at the interface, further enhancing the density of the solid electrolyte layer. Specifically, controlling the etching depth to 3μm–40μm is particularly beneficial for providing appropriately sized ventable microchannels and promoting more complete interlocking of interface materials, thus further improving the density of the solid electrolyte layer.

[0415] In the aforementioned methods, the formation of the electrolyte pre-coating can be a dry method or a wet method. When using a wet method, an electrolyte slurry comprising a solid electrolyte and an organic solvent needs to be prepared. Non-limitingly, the organic solvent in the electrolyte slurry can include one or more of p-xylene, trimethylbenzene, butyl butyrate, heptane, etc., and more specifically, p-xylene. To improve the dispersibility of solid particles in the slurry, appropriate amounts of auxiliary components such as organic binders and organic dispersants can also be added to the electrolyte slurry.

[0416] In some embodiments, a method for preparing a solid-state battery is provided, which includes the following steps:

[0417] S110: Provides a solid electrolyte membrane including a first surface and a second surface that are opposite to each other; wherein the solid electrolyte membrane includes a degradable organic component;

[0418] S120: The first surface of the solid electrolyte membrane is etched to form a first rough surface with a first concave portion. The solid electrolyte membrane after etching includes a first convex portion corresponding to the first concave portion. After etching, the content of degradable organic components in the first convex portion decreases.

[0419] S130: A first electrode pre-coating layer is formed on the first surface after etching in the solid electrolyte membrane. The first electrode pre-coating layer is pressed so that the first protrusion and the portion of the first electrode pre-coating layer filled in the corresponding first recess together form a first interface functional layer, and the remaining portion of the first electrode pre-coating layer forms a first electrode layer.

[0420] S140: A second electrode layer is formed on the second surface of the solid electrolyte membrane.

[0421] In this application, unless otherwise specified, in step S130, "the remaining part of the first electrode pre-coating" refers to the part of the first electrode pre-coating that is not filled in the first recess. Unless otherwise specified, it can be understood as the part of the first electrode pre-coating that is not in contact with the first rough surface in the thickness direction.

[0422] Two electrode layers can be sequentially fabricated on a solid electrolyte membrane containing biodegradable organic components. By etching the surface of the solid electrolyte membrane, the biodegradable organic components are partially or completely removed, reducing the organic component content. On the one hand, the decrease in organic component content can lead to an increase in the inorganic component content in the etched area on the surface of the solid electrolyte membrane, thereby improving the conductivity of the solid electrolyte membrane surface, reducing interfacial impedance, and improving the battery's electrochemical performance, including cycle performance. In addition, it is also beneficial to improve discharge capacity and rate performance. On the other hand, a first rough surface with concave areas can be formed on the surface of the solid electrolyte membrane. When further fabricating the first electrode layer, a ventable microchannel can be formed between the formed first electrode layer and the first rough surface. During subsequent pressing processes (such as warm isostatic pressing), these microchannels can be used to vent, increasing the pressing degree of the first electrode layer and improving the density of the formed first electrode layer. Furthermore, the first rough surface can also increase the contact area between the first electrode layer and the first electrode layer, which is also beneficial to reducing interfacial impedance and thus improving battery performance, including at least improving battery cycle performance.

[0423] In some embodiments, forming a second electrode layer on the second surface of a solid electrolyte membrane includes the following steps:

[0424] S150: The second surface of the solid electrolyte membrane is etched to form a second rough surface with a second concave portion. The solid electrolyte membrane after etching includes a second convex portion corresponding to the second concave portion. After etching, the content of degradable organic components in the second convex portion decreases.

[0425] S160: A second electrode pre-coating layer is formed on the second surface after etching in the solid electrolyte membrane. The second electrode pre-coating layer is pressed so that the second protrusion and the portion of the second electrode pre-coating layer filled in the corresponding second recess together form a second interface functional layer, and the remaining portion of the second electrode pre-coating layer forms a second electrode layer.

[0426] In this application, unless otherwise specified, in step S160, "the remaining portion of the second electrode pre-coating" refers to the portion of the first electrode pre-coating that is not filled in the second recess. Unless otherwise specified, it can be understood as the portion of the second electrode pre-coating that is not in contact with the second rough surface in the thickness direction.

[0427] When forming a second electrode on the other side of the solid electrolyte membrane, the content of degradable organic components in the etched area can be reduced and a second rough surface can be formed by etching the surface of the solid electrolyte membrane. This improves the conductivity of the solid electrolyte membrane surface, reduces the interfacial impedance, and forms ventable microchannels between the formed second electrode layer and the second rough surface. During subsequent pressing processes (such as warm isostatic pressing), these microchannels can be used to vent, increasing the pressing degree of the second electrode layer and improving the density of the formed second electrode layer. In addition, the second rough surface can also increase the contact area with the second electrode layer, which is also beneficial to reducing the interfacial impedance and thus improving battery performance, including at least improving battery cycle performance.

[0428] In the aforementioned methods, the formation of the first electrode pre-coating or the second electrode pre-coating can be a dry method or a wet method. When using a wet method, a corresponding electrode slurry needs to be prepared. Refer to the aforementioned methods for preparing positive and negative electrode slurries.

[0429] In some embodiments, the first electrode layer is a positive electrode layer, or the first electrode layer is a negative electrode layer.

[0430] Based on a solid electrolyte membrane, either the positive electrode layer or the negative electrode layer can be formed first.

[0431] In some embodiments, the surface of the solid electrolyte membrane near the positive electrode layer is etched before the positive electrode layer is formed; the density of the positive electrode layer is denoted as K. P Satisfying K P ≥90%, etching depth of 1μm~50μm; optionally, K P ≥97%, with an etching depth of 3μm~40μm.

[0432] By controlling the etching depth of the solid electrolyte membrane, the density of the positive electrode layer formed based on the etched solid electrolyte membrane can be adjusted.

[0433] In some embodiments, the surface of the solid electrolyte membrane near the negative electrode layer is etched before the negative electrode layer is formed; the density of the negative electrode layer is denoted as K. N Satisfying K N ≥90%, etching depth of 1μm~50μm; optionally, K N ≥97%, with an etching depth of 3μm~40μm.

[0434] By controlling the etching depth of the solid electrolyte membrane, the density of the negative electrode layer formed based on the etched solid electrolyte membrane can be adjusted.

[0435] In some embodiments, the etching method used to perform the etching process includes one or more of plasma processing and laser processing.

[0436] In some embodiments, the etching method used to perform the etching process includes one or more of oxygen plasma processing and infrared laser processing.

[0437] For those skilled in the art, based on the selected etching method, the composition of the selected substrate to be etched, and the required etching depth, they can select appropriate etching equipment to complete the required etching process.

[0438] Taking plasma processing as an example, those skilled in the art can employ, but are not limited to, oxygen plasma etching. Inductively coupled plasma (ICP) etching can be used for oxygen plasma etching. Furthermore, during oxygen plasma etching, the etching effect can be adjusted by controlling one or more of the following parameters: ICP power, bias power, oxygen flow rate, chamber pressure, etching time, radio frequency, substrate temperature, electrode indirection, etc. As an example, adjusting the ICP power can regulate the plasma density and energy, thereby affecting the etching rate and uniformity; adjusting the etching time, under the same conditions of other etching parameters, can essentially directly determine the etching depth, allowing for precise control of the required etching amount; adjusting the bias power can regulate the bombardment energy and direction of ions on the sample surface, thereby affecting the anisotropy of etching and the degree of surface damage; regulating the oxygen flow rate can regulate the rate of the chemical reaction; and regulating the chamber pressure can regulate the plasma collision frequency and the mean free path of the particles, thereby affecting the etching effect. In this application, the etching depth can be adjusted by one or more of the following parameters: ICP power, etching time, number of etching processes, etc., but is not limited to these. Other parameters can be adjusted auxiliaryly or adaptively. For example, the ICP power and bias power usually need to be coordinated and balanced. Given the selected ICP power, those skilled in the art can choose a suitable bias power.

[0439] For oxygen plasma etching, unless otherwise specified, etching power refers to ICP power.

[0440] Non-limitingly, plasma treatment can be performed as follows: plasma treatment is carried out for 1 to 60 seconds in the presence of oxygen. The gas atmosphere may include one or more gases such as argon and hydrogen, in addition to oxygen. Non-limitingly, taking lithium-ion battery etching (ICP) as an example, the ICP etching power can be 500 W to 10 kW, further such as 3 kW to 10 kW, but not limited thereto; the bias power can be 10 W to 1000 W, further such as 50 W to 500 W, but not limited thereto; the chamber pressure condition can be 1 mTorr to 50 mTorr, further such as 3 mTorr to 20 mTorr, but not limited thereto; the etching time per cycle can be 1 to 60 seconds, further preferably 10 to 60 seconds, further preferably 10 to 30 seconds, but not limited thereto; the oxygen gas flow rate can be 2 sccm to 40 sccm, preferably 2 sccm to 30 sccm, but not limited thereto. In a non-limiting manner, the etching time can be any of the following durations or a range consisting of any two of the following durations: 5s, 6s, 8s, 10s, 15s, 20s, 25s, 30s, 35s, 40s, 45s, 50s, 55s, 60s, etc.

[0441] In this application, 1 mTorr corresponds to the pressure of 1 micrometer of mercury, which is one-thousandth of the pressure of 1 millimeter of mercury. 1 mTorr is approximately equal to 0.133 Pa.

[0442] In this application, sccm is a gas flow unit, which stands for standard cubic centimeter per minute, representing a flow rate of 1 cubic centimeter per minute.

[0443] Taking laser etching as an example, those skilled in the art can employ, but are not limited to, infrared laser etching. During laser etching, the etching effect can be adjusted by controlling one or more of the following parameters: laser power, scanning speed, pulse frequency, focused spot size, and number of repetitions. As an example, laser power can be used to control the etching rate and etching depth, scanning speed can be used to adjust the laser's movement speed on the material surface, pulse frequency can affect the energy injection per unit time, and focused spot size can affect the etching accuracy. In this application, the etching depth can be adjusted primarily by one or more of the following parameters: laser power, etching time, and number of etching processes, but is not limited to these. Other parameters can be adjusted auxiliaryly or adaptively.

[0444] Unless otherwise specified, when laser etching is involved, etching power refers to laser power.

[0445] Non-limitingly, laser processing can be performed using a wavelength of 0.75 μm to 14 μm. Non-limitingly, the etching power can be from 5 kW to 20 kW, but is not limited thereto; the etching time per cycle can be from 1 s to 60 s, but is not limited thereto. Non-limitingly, the etching time per cycle can be any of the following durations or a range selected from any two of the following durations: 5 s, 6 s, 8 s, 10 s, 15 s, 20 s, 25 s, 30 s, 35 s, 40 s, 45 s, 50 s, 55 s, 60 s, etc. In some embodiments, laser processing is performed using a wavelength of 3 μm to 5 μm, and the etching time per cycle is from 1 s to 60 s.

[0446] It is understandable that when a large etching depth is required, such as when the etching depth exceeds 5μm, etching can be performed in multiple stages to achieve the required etching depth.

[0447] Non-limitingly, when performing oxygen plasma treatment on the negative electrode sheet, an etching power of 3kW-8kW can be used; when performing plasma treatment on the positive electrode sheet, an etching power of 5kW-10kW can be used; and when performing plasma treatment on the solid electrolyte membrane, an etching power of 3kW-8kW can be used.

[0448] Non-limitingly, when laser processing the negative electrode sheet, a power setting of 5kW-10kW can be used; when laser processing the positive electrode sheet, an etching power of 10kW-20kW can be used; and when laser processing the solid electrolyte membrane, an etching power of 5kW-10kW can be used.

[0449] In a third aspect of this application, an electrical device is provided, comprising at least one of the solid-state battery described in the first aspect of this application and a solid-state battery prepared by the method described in the second aspect of this application.

[0450] In some embodiments, the electrical device includes at least one of the solid-state batteries of any of the embodiments provided in this application.

[0451] In a non-limiting sense, solid-state batteries can be used as a power source for electrical devices or as an energy storage unit for electrical devices. Electrical devices can include, but are not limited to, mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc. Mobile devices can be, for example, mobile phones, laptops, etc.; electric vehicles can be, for example, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, electric motorcycles, power tools, etc., but are not limited to these. This electrical device can also be applied to military equipment, aerospace, and other fields, and can also be applied to energy storage power systems such as hydroelectric, thermal, wind, and solar power plants.

[0452] As an electrical device, solid-state batteries can be selected based on its usage requirements.

[0453] Figure 14 shows an example of an electrical device 6. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of this electrical device for solid-state batteries, a battery pack or battery module can be used.

[0454] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a thin and light design and can use solid-state batteries as their power source.

[0455] The following describes some embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where the technology or conditions are not specified in the embodiments, they are performed according to the description above, or according to the technology or conditions described in the literature in the art, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially, or can be synthesized from commercially available products using conventional methods.

[0456] In the following examples, room temperature refers to 20°C to 30°C.

[0457] Unless otherwise specified, the following examples use the following method for counting "approximations" in micrometers (μm) or nanometers (nm): for values ​​accurate to a single digit between 1 and 9, the fluctuation range is within ±0.5; for values ​​accurate to a single digit between 10 and 99, the fluctuation range is within ±1.

[0458] It should be noted that the following embodiments and examples use all-solid-state batteries as non-limiting examples of solid-state batteries, and the raw material composition is a non-limiting example, for example, using a sulfide solid electrolyte as a non-limiting example of a solid electrolyte.

[0459] In the following examples, unless otherwise stated, the operations or reaction steps involving sulfide solid electrolyte materials as raw materials are carried out in an argon atmosphere.

[0460] In the following examples, unless otherwise specified, the use of organic solvents to disperse sulfide solid electrolyte materials is involved. The organic solvent may be one or more of p-xylene, trimethylbenzene, butyl butyrate, heptane, etc., and may further be p-xylene.

[0461] In the following examples, unless otherwise specified, the D of the positive electrode active particle NCM811 powder is... v 50 is 4μm (positive electrode active material is NCM) 811 ), D of the sulfide solid electrolyte Li6PS5Cl v50 represents 1 μm, and the D of silicon oxide (SiOx) v 50 represents 4.5 μm. Unless otherwise specified, the value of x in silicon oxide SiOx is basically equal, and x is in the range of 1 to 2.

[0462] Unless otherwise stated in this application, D v 50 represents the particle size at which the cumulative volume distribution percentage of the multi-particle mixture reaches 50%.

[0463] D v Test of 50:

[0464] In the following embodiments and comparative examples, the D of the solid raw material... v 50 can be tested and confirmed using the following method: Equipment model: Malvern 2000 (MasterSizer 2000) laser particle size analyzer; Reference standard procedure: GB / T19077-2016 / ISO 13320:2009; Detailed test procedure: Take an appropriate amount of the sample to be tested (the sample concentration should be 8%-12% (w / v) with an opacity of light), add 20 mL of organic solvent (such as p-xylene), and simultaneously incubate for 5 minutes (53 kHz / 120 W) to ensure complete dispersion of the sample. Then, determine the sample according to the GB / T19077-2016 / ISO 13320:2009 standard. When testing sulfide solid electrolytes, a dispersant, polycarboxylic acid, is also added.

[0465] In the following embodiments, parameters not described in the conditions for plasma etching or laser etching remain consistent across different embodiments or can be adjusted accordingly based on the selected parameters. When a large etching depth is required, such as an etching depth exceeding 5 μm, etching can be performed in multiple stages to achieve the desired etching depth. Each etching session can last from 10 s to 30 s, or other suitable etching times can be used.

[0466] Example 1. A solid electrolyte layer and a positive electrode layer are formed by etching the negative electrode sheet. The etching method is plasma treatment.

[0467] 1. Preparation of negative electrode sheet

[0468] In an argon atmosphere, silicon oxide (SiOx) negative electrode active particles, Li6PS5Cl sulfide solid electrolyte powder, and polyvinylidene fluoride (PVDF) binder were dispersed in p-xylene solvent (60 wt% solid content) at a mass ratio of 80:17:3 to obtain a negative electrode slurry. The negative electrode slurry was coated with a surface density of 4.5 mg / cm² on a dry weight basis (excluding solvent). 2 The coating is applied to one side of a copper foil, dried, and cold-pressed to obtain a negative electrode sheet. This negative electrode sheet includes a negative current collector copper foil and a negative electrode active initial layer located on one side of the negative current collector. The thickness of the negative electrode active initial layer is approximately 39 μm.

[0469] 2. Etching treatment: Oxygen plasma etching treatment.

[0470] Under an oxygen atmosphere, the initial active layer of the negative electrode was etched to the target etching depth (see Table 1) using an ICP etching power of 5 kW, a chamber pressure of 10 mTorr, and an oxygen flow rate of 20 sccm. Degradation products formed during etching were removed using negative pressure. The etching process created a rough surface on the negative electrode. The remaining portion of the etched area formed the negative electrode protrusions, and the concave areas formed between these protrusions constituted the negative electrode concave areas. The unetched initial active layer of the negative electrode corresponds to the negative electrode active material layer. The copper foil and the negative electrode active material layer together constitute the negative electrode layer.

[0471] 3. Formation of a solid electrolyte layer.

[0472] A sulfide solid electrolyte powder, Li6PS5Cl, was deposited on one side of the initial active layer of the negative electrode sheet and cold-pressed into a film at a pressure of 360 MPa for 5 minutes. A functional layer at the negative electrode interface was formed at the rough surface of the negative electrode, comprising a first sublayer on the negative electrode side and a second sublayer on the solid electrolyte layer side. The solid electrolyte layer is bonded to the negative electrode active material layer through the second sublayer. The thickness, based on the solid electrolyte powder, is approximately 90 μm.

[0473] 4. Formation of the positive electrode layer.

[0474] In an argon atmosphere, positive electrode active particles LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), sulfide solid electrolyte Li6PS5Cl, conductive agent VGCF (vapor-grown carbon fiber), and binder polytetrafluoroethylene (PTFE) are uniformly dispersed in xylene solvent at a mass ratio of 85:13:1:1 to obtain a positive electrode slurry. The positive electrode slurry is then coated onto the exposed surface of the solid electrolyte layer and dried to form the positive electrode layer. The areal density of the positive electrode slurry, based on dry weight (excluding solvent), is approximately 30 mg / cm³. 2 .

[0475] Example 2. After etching the negative electrode sheet, a solid electrolyte layer and a positive electrode layer are formed. The etching method is laser etching.

[0476] The same method as in Example 1 was used for preparation, the main difference being that the etching method was changed to laser treatment in step 2. An infrared laser with a wavelength of about 4 μm was used to etch to the target etching depth (see Table 1), and the etching power was 8 kW. The operation methods of the remaining steps were the same as in Example 1.

[0477] Examples 3-5 employ essentially the same method as Example 1, with the main difference being the alteration of one or more of the types and amounts of organic components in the negative electrode sheet. The mass ratio of the negative electrode active material to the solid electrolyte remains essentially the same in Examples 3-5, and the areal density of the sulfide solid electrolyte powder in step 3 is essentially the same as in Example 1. See also Table 1.

[0478] Example 3. The negative electrode slurry was changed to: negative electrode active particles, sulfide solid electrolyte powder Li6PS5Cl, and binder polyacrylic acid (PAA) were dispersed in the solvent p-xylene (solid content about 60wt%) at a mass ratio of 80.8:17.2:2 to obtain the negative electrode slurry.

[0479] Example 4. The negative electrode slurry was changed to: negative electrode active particles, sulfide solid electrolyte powder Li6PS5Cl and binder PVDF were dispersed in xylene solvent (solid content about 60wt%) at a mass ratio of 75.9:16.1:8 to obtain the negative electrode slurry.

[0480] Example 5. The negative electrode slurry was changed to: negative electrode active particles, sulfide solid electrolyte powder Li6PS5Cl and binder PVDF were dispersed in xylene solvent (solid content about 60wt%) at a mass ratio of 74.2:15.8:8:2 to obtain negative electrode slurry.

[0481] Examples 6-9 employ essentially the same method as in Example 1, except that one or both of the etching power and etching time are changed to adjust the etching depth. See Table 1 for details.

[0482] Example 10. A solid electrolyte layer and a negative electrode layer are formed by etching the positive electrode sheet. The etching method is plasma treatment.

[0483] 1. Preparation of positive electrode sheet

[0484] In an argon atmosphere, LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), sulfide solid electrolyte Li6PS5Cl, conductive agent VGCF (vapor-grown carbon fiber), and binder polytetrafluoroethylene (PTFE) were weighed at a mass ratio of 85:13:1:1 and mixed evenly in a double planetary mixer. The mixed powder was then heated and pressurized in an internal mixer to form a granular material. This material was then hot-rolled at 80°C to form a self-supporting positive electrode sheet (used as the initial active layer). This self-supporting positive electrode sheet was then hot-rolled and combined with a positive current collector Al foil to obtain the positive electrode sheet. This positive electrode sheet includes a positive current collector and an initial active layer located on one side of the current collector. The areal density of the initial active layer is approximately 30 mg / cm³. 2 It has a thickness of approximately 91 μm.

[0485] 2. Etching treatment: Oxygen plasma etching treatment.

[0486] Under an oxygen atmosphere, the initial active layer of the positive electrode was etched to the target etching depth (see Table 1) at an etching power of 8 kW, a chamber pressure of 15 mTorr, and an oxygen flow rate of 25 sccm. Degradation products formed during etching were removed using negative pressure. The etching process created a rough surface on the positive electrode. The remaining portion of the etched area formed the positive electrode convexity, and the concave areas formed between the convexities were the positive electrode concaveness. The unetched initial active layer of the positive electrode corresponds to the positive electrode active material layer. The positive electrode current collector aluminum foil and the positive electrode active material layer together constitute the positive electrode layer.

[0487] 3. Formation of a solid electrolyte layer.

[0488] The sulfide solid electrolyte powder Li6PS5Cl was spread on one side of the initial active layer of the positive electrode sheet and cold-pressed into a film at a pressure of 360 MPa for 5 minutes. A positive electrode interface functional layer was formed at the rough surface of the positive electrode, including a first sub-layer on the positive electrode side and a second sub-layer on the solid electrolyte layer side. The solid electrolyte layer is connected to the positive electrode active material layer through the second sub-layer.

[0489] The amount of solid electrolyte powder per unit area is the same as in Example 1.

[0490] 4. Formation of a negative electrode layer.

[0491] In an argon atmosphere, a negative electrode active particle (silicon oxide), a sulfide solid electrolyte powder (Li6PS5Cl), and a binder (PVDF) were dispersed in p-xylene (solid content 60 wt%) at a mass ratio of 80:17:3 to obtain a negative electrode slurry. The negative electrode slurry was then coated onto the exposed surface of the solid electrolyte layer and dried to form the negative electrode layer. The areal density of the negative electrode slurry, based on dry weight (excluding solvent), was approximately 4.5 mg / cm³. 2 The surface density is close to that of the initial coating layer of the negative electrode active layer in Example 1.

[0492] Example 11. The method is basically the same as in Example 10, except that the etching power and etching time are changed to adjust the etching depth. See Table 1.

[0493] Example 12. A positive electrode layer is formed by etching one side of a solid electrolyte membrane.

[0494] 1. Preparation of solid electrolyte membranes

[0495] The sulfide electrolyte Li6PS5Cl powder and the binder PVDF were mixed evenly at a mass ratio of 97:3, and pre-pressed at 100MPa without holding pressure.

[0496] The amount of solid electrolyte Li6PS5Cl per unit area is the same as in step 3 of Example 1.

[0497] 2. Perform unilateral etching on the first surface: oxygen plasma treatment.

[0498] Under an oxygen atmosphere, one surface (first surface) of the solid electrolyte membrane was etched to the target etching depth (see Table 1) at an etching power of 5 kW, a chamber pressure of 10 mTorr, and an oxygen flow rate of 20 sccm. The degradation products formed by the etching were removed using negative pressure. The etching process created a first rough surface, with the remaining portion of the etched area forming a first convex portion. The concave areas formed between the first convex portions constitute the first concave portion, and the unetched portion of the solid electrolyte membrane corresponds to the solid electrolyte layer.

[0499] 3. A positive electrode layer is formed based on the etched first surface.

[0500] In an argon atmosphere, positive electrode active particles LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), sulfide solid electrolyte Li6PS5Cl, conductive agent VGCF (vapor-grown carbon fiber), and binder polytetrafluoroethylene (PTFE) are uniformly dispersed in xylene solvent at a mass ratio of 85:13:1:1 to obtain a positive electrode slurry. The positive electrode slurry is coated onto the first roughened surface, dried, and cold-pressed into a film at a pressure of 360 MPa for 5 minutes to form a positive electrode layer. A positive electrode interface functional layer is formed between the positive electrode layer and the solid electrolyte layer.

[0501] The coating surface density of the positive electrode slurry is basically the same as that in step 4 of Example 1.

[0502] 4. A negative electrode layer is formed based on the unetched second surface.

[0503] In an argon atmosphere, the negative electrode active particles silicon oxide, sulfide solid electrolyte powder Li6PS5Cl and binder PVDF are dispersed in the solvent p-xylene (solid content 60wt%) at a mass ratio of 80:17:3 to obtain a negative electrode slurry. The negative electrode slurry is then coated on the exposed surface of the solid electrolyte layer and dried to form a negative electrode layer.

[0504] The surface density of the negative electrode slurry coating is basically the same as that in step 4 of Example 10.

[0505] Example 13. After etching both sides of the solid electrolyte membrane, a positive electrode layer and a negative electrode layer are formed sequentially.

[0506] The method is basically the same as in Example 12, except that in the etching process step 2, the second surface is also etched to form a second rough surface. The remaining portion of the etched area on one side of the second rough surface forms a second convex portion, and the concave area formed between the second convex portions is a second concave portion. The unetched solid electrolyte film portion corresponds to the solid electrolyte layer; in step 4, a negative electrode layer is formed based on the etched second surface.

[0507] 1. Preparation of solid electrolyte membranes

[0508] The sulfide electrolyte Li6PS5Cl powder and the binder PVDF were mixed evenly at a mass ratio of 97:3, and pre-pressed at 100MPa without holding pressure.

[0509] The amount of solid electrolyte Li6PS5Cl per unit area is the same as in step 1 of Example 12.

[0510] 2. Perform double-sided etching on the first and second surfaces: oxygen plasma treatment.

[0511] Under an oxygen atmosphere, the etching parameters for the first and second surfaces are the same: etching power of 5kW, chamber pressure of 10mTorr, and oxygen flow rate of 20sccm are used to etch the first and second surfaces to the target etching depth (see Table 1).

[0512] On the first surface side, a first rough surface is formed by etching. The remaining portion of the etched area on this side forms a first protrusion. The concave area formed between the first protrusions is a first concave.

[0513] On the second surface side, a second rough surface is formed by etching. The remaining part of the etched area on this side forms a second convex part, and the concave area formed between the second convex parts is a second concave part.

[0514] The unetched solid electrolyte membrane portion corresponds to the solid electrolyte layer, and the negative electrode layer is formed based on the etched second surface.

[0515] 3. A positive electrode layer is formed based on the etched first surface.

[0516] In an argon atmosphere, positive electrode active particles LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), sulfide solid electrolyte Li6PS5Cl, conductive agent VGCF (vapor-grown carbon fiber), and binder polytetrafluoroethylene (PTFE) are dispersed evenly in xylene solvent at a mass ratio of 85:13:1:1 to obtain a positive electrode slurry. The positive electrode slurry is coated on the first rough surface and dried.

[0517] The surface density of the positive electrode slurry coating is basically the same as that in step 3 of Example 12.

[0518] In an argon atmosphere, the negative electrode active particles silicon oxide, sulfide solid electrolyte powder Li6PS5Cl and binder PVDF are dispersed in the solvent p-xylene (solid content 60wt%) at a mass ratio of 80:17:3 to obtain a negative electrode slurry. The negative electrode slurry is then coated on the second rough surface and dried.

[0519] The material undergoes cold pressing at 360 MPa for 5 minutes to form a positive electrode layer and a negative electrode layer. A positive electrode interface functional layer is formed between the positive electrode layer and the solid electrolyte layer, and a negative electrode interface functional layer is formed between the negative electrode layer and the solid electrolyte layer.

[0520] The surface density of the negative electrode slurry coating is basically the same as that in step 4 of Example 12.

[0521] Example 14. The method is basically the same as that in Example 1, except that an intermediate functional layer without organic components is introduced separately; in this example, the solid-state battery includes a negative electrode layer, an intermediate functional layer, a solid electrolyte layer and a positive electrode layer stacked in sequence.

[0522] 1. Preparation of negative electrode sheet

[0523] In an argon atmosphere, silicon oxide negative electrode active particles, Li6PS5Cl sulfide solid electrolyte powder, and PVDF binder are dispersed in xylene solvent (solid content 60wt%) at a mass ratio of 80:17:3 to obtain a negative electrode slurry. The negative electrode slurry is coated on one side of a copper foil, dried, and cold-pressed to obtain a negative electrode sheet. The negative electrode sheet includes a copper foil as a negative electrode current collector and a layer of negative electrode active material located on the side of the negative electrode current collector.

[0524] The negative electrode slurry was coated with a surface density of 4.5 mg / cm² (dry weight, after deducting solvent). 2 The thickness of the negative electrode active material layer is controlled to be approximately 27 μm.

[0525] 2. Preparation of intermediate functional layer and solid electrolyte layer

[0526] In an argon atmosphere, silicon oxide anode active particles, Li6PS5Cl sulfide solid electrolyte powder, and PVDF binder were uniformly mixed at a mass ratio of 80:19:1, spread on the anode active material layer, and cold-pressed into a film at a pressure of 360 MPa for 3 minutes. This formed an intermediate functional layer with a thickness of approximately 12 μm, which is basically the same as the thickness of the anode interface functional layer in Example 1.

[0527] 3. Formation of a solid electrolyte layer.

[0528] The sulfide solid electrolyte powder Li6PS5Cl was spread on the exposed side of the intermediate functional layer and cold-pressed into a film at a pressure of 360 MPa for 5 min.

[0529] In this example, the thickness of the solid electrolyte layer is controlled in a manner consistent with step 3 of Example 1.

[0530] 4. Formation of the positive electrode layer.

[0531] In an argon atmosphere, positive electrode active particles LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), sulfide solid electrolyte Li6PS5Cl, conductive agent VGCF (vapor-grown carbon fiber), and binder polytetrafluoroethylene (PTFE) are dispersed uniformly in xylene solvent at a mass ratio of 85:13:1:1 to obtain a positive electrode slurry. The positive electrode slurry is coated on the exposed surface of the solid electrolyte layer and dried to form a positive electrode layer.

[0532] The coating surface density of the positive electrode slurry is basically the same as that in step 4 of Example 1.

[0533] Example 15. The method is basically the same as that in Example 14, except that the mass ratio of the negative electrode active particles silicon oxide and the sulfide solid electrolyte powder Li6PS5Cl in step 2 is the same as that in the negative electrode layer.

[0534] Step 2: Preparation of the intermediate functional layer and the solid electrolyte layer:

[0535] In an argon atmosphere, the negative electrode active particles silicon oxide and sulfide solid electrolyte powder Li6PS5Cl are uniformly mixed at a mass ratio of 80:17, spread on the negative electrode active material layer, and cold-pressed into a film at a pressure of 360MPa for 3min.

[0536] An intermediate functional layer with a thickness of approximately 12 μm is formed, which is basically the same as the thickness of the intermediate functional layer in Example 14.

[0537] Comparative Example 1. Based on Example 1, the etching step is omitted.

[0538] Comparative Example 2. Based on Example 10, the etching step is omitted.

[0539] Comparative Example 3. Based on Example 12, the single-sided etching step is omitted.

[0540] Comparative Example 4. Based on Example 13, the double-sided etching step is omitted.

[0541] The preparation parameters for each embodiment and comparative example can also be found in Tables 1 and 2.

[0542] Table 1.

[0543] Table 1. The content of each component refers to the mass percentage relative to the corresponding electrode active material layer.

[0544] Performance testing and analysis:

[0545] (I) Representation of the Interface Functional Layer

[0546] 1. Etching depth

[0547] The cross-section of the sample was observed using a ZEISS Sigma 300 scanning electron microscope. The sample to be tested was obtained by quenching the solid battery cell along its thickness direction using liquid nitrogen.

[0548] 2. Structural and compositional characterization

[0549] Test objects: the interface functional layer, the first sublayer and the second sublayer in the prepared solid-state battery; intermediate samples after surface etching during the preparation process.

[0550] Test Method 1: Using the FEI Scios 2HiVac instrument. Combining cryo-focused electron beam (FIB) continuous slicing, cross-sectional SEM morphology observation, energy dispersive spectroscopy (EDS) elemental energy dispersive spectroscopy, and 3D reconstruction analysis software, the sample was finely sliced ​​(down to nanoscale thin sections) using the nanoscale dynamic resolution and layer-by-layer cutting technique of FIB-SEM. The morphology, structure, and elemental distribution of each cross-section were analyzed using scanning electron microscopy (SEM) under FIB continuous slicing. The 3D structure of the sample was then reconstructed using 3D structure reconstruction software.

[0551] Test Method 2: The solid-state battery cell was quenched in the thickness direction using liquid nitrogen, and the microstructure of the fracture surface was then observed. ZEISS Sigma300 scanning electron microscope was used.

[0552] Test Method 3: Computed Tomography (CT) Scan. Instrument: Phoenix V|tome|x S240.

[0553] (ii) Characterization of electrical conductivity and density.

[0554] 1. Ionic conductivity testing of materials in each structural layer

[0555] Sample preparation: Disassemble the battery, extract the structural layer sample to be tested, and grind it into a uniform powder.

[0556] Methods: Ionic conductivity was determined by electrochemical impedance spectroscopy (EIS). The detailed procedure was as follows: The powder to be tested was poured into a 10 mm diameter tableting mold and pressed into a dense film at 360 MPa. Then, a 10 mm diameter cylindrical stainless steel current collector was used to clamp the film within the mold at 120 MPa. The current collector was then connected to an electrochemical workstation with a bias voltage of 10 mV and a frequency range of 10... 6 Electrochemical impedance spectroscopy (EIS) was performed on the membrane in the range of Hz to 10Hz. The intersection of the curve in the electrochemical impedance spectrum from the high frequency band to the low frequency band with the Z' axis was recorded as the resistance value R. The ionic conductivity can be calculated using formula (1):

[0557] Where d is the diaphragm thickness and A is the contact area between the diaphragm and the current collector.

[0558] The results of comparing the relative magnitudes of conductivity of each structural layer with those obtained by EIS method are consistent.

[0559] 2. Density characterization of structural layers formed on etched substrates

[0560] The density parameter K of each structural layer was detected and analyzed using a true density meter (such as G-DenPyc 3900M). E .

[0561] (III) The electrochemical performance of the all-solid-state battery was tested using a solid-state mold battery. The battery test window was 2.8V to 4.3V (for lithium potential).

[0562] 1. Initial discharge capacity

[0563] The testing procedure was as follows: The assembled all-solid-state battery was charged to 3.68V (4.3V for lithium) at a current density of 0.1C, allowed to stand for 10 minutes, and then discharged to 1.98V (2.6V for lithium) at a current density of 0.1C to obtain the battery's initial discharge capacity. The battery was tested at 25±3℃, where 1C = 200mA / g.

[0564] 2. First Coulomb efficiency

[0565] The initial coulombic efficiency of a battery can be obtained by dividing the initial discharge capacity obtained from the test at 0.1C by the initial charge capacity.

[0566] 3. Ratio performance

[0567] The testing process is as follows: The charging rate of the all-solid-state battery was fixed at 0.1C, and then it was discharged at rates of 0.1C, 0.33C, 1C, 2C, and 3C, respectively, with 3 cycles at each rate. The battery voltage test window was 2.8–4.3V vs. Li + / Li, the battery was tested at 25±3℃, where 1C=200mA / g.

[0568] 4. Cyclic performance:

[0569] The testing process is as follows: The assembled all-solid-state battery was first activated by charge-discharge at 0.1C for 3 cycles, and then subjected to a long-cycle test at 0.33C for 200 cycles. The cycle capacity retention rate of the battery was calculated. The battery voltage test window is 2.8–4.3V vs. Li + / Li (Li potential, active ion is Li) + The battery was tested at 25±3℃, where 1C=200mA / g.

[0570] The test results can be found in Table 2, "Capacity retention rate after 200 cycles, 0.33C".

[0571] 5. Battery internal resistance DCR

[0572] DCR Test: At 25℃, charge the battery at a constant current of 1 / 3C to 3.65V, then charge it at a constant voltage of 3.65V until the current is 0.05C. After resting for 5 minutes, discharge it at a constant current of 1 / 3C for 90 minutes, and then rest for 120 minutes. Record the voltage V1. Then discharge it at 4C for 30 seconds and record the voltage V2. The internal resistance DCR of the battery is obtained by dividing (V2-V1) / 4C.

[0573] The test results can be found in Table 2, under "Battery Internal Resistance (DCR)".

[0574] Test analysis results:

[0575] Based on the cross-sectional morphology analysis, each of the embodiments 1-15 formed an interface functional layer. Compared with the comparative embodiments 1-4 without this interface functional layer, the cycle performance was significantly improved. In addition, the battery internal resistance was also significantly reduced.

[0576] Examples 1-9 and 14-15 form a negative electrode interface functional layer, Examples 10-11 and 12 form a positive electrode interface functional layer, and Example 13 forms both a positive electrode interface functional layer and a negative electrode interface functional layer.

[0577] Based on the combined FIB-SEM and EDS test results, the organic component content of the interface functional layer in Examples 1-11 is lower than that of the adjacent electrode layer; the organic component content of the interface functional layer in Examples 12-13 is lower than that of the solid electrolyte layer; and the organic component content of the negative electrode interface functional layer in Example 13 is even lower than that of the negative electrode layer. Based on the feed amount, the organic component content of the intermediate functional layer (as the negative electrode interface functional layer) in Examples 14-15 is lower than that of the adjacent negative electrode layer.

[0578] Based on the battery performance test results, the introduction of the interface functional layer in each embodiment, compared to the comparative example without the interface functional layer, also improved the discharge capacity, initial coulombic efficiency, and rate performance of the solid-state battery. As an example, Table 3 lists the comparative data between Embodiment 1 and Comparative Example 1.

[0579] Examples 1-13 were formed using an in-situ method. In each example, a portion of the interface functional layer became an extension region of the adjacent electrode active material layer, and another portion of the interface functional layer became an extension region of the solid electrolyte layer. Compared to Comparative Example 1, the improvement in cycle performance and the decrease in battery internal resistance in Examples 1-13 were particularly significant.

[0580] Examples 1-13 were formed using an in-situ method. In each example, the interface functional layer has an interleaved interface, including a first sub-layer on one side of the electrode layer and a second sub-layer on the side of the solid electrolyte membrane. Furthermore, there is an interleaved interface between the first sub-layer and the second sub-layer, such that a portion of the interface functional layer becomes an extension region of the adjacent electrode active material layer, and another portion of the interface functional layer becomes an extension region of the solid electrolyte layer.

[0581] Based on the test results of the powder samples of each structural layer obtained from the disassembled battery, the ionic conductivity of the interface functional layer material in Examples 1-13 is higher than that of the adjacent electrode layer material and also higher than that of the solid electrolyte layer material. Correspondingly, the conductivity of the interface functional layer in Examples 1-13 is higher than that of the adjacent electrode layer and also higher than that of the solid electrolyte layer.

[0582] According to the density test results, the density of the solid electrolyte layer in Examples 1-9 is higher than that in Comparative Example 1; the density of the solid electrolyte layer in Examples 10-11 is higher than that in Comparative Example 2; the density of the positive electrode layer in Example 12 is higher than that in Comparative Example 3; and the density of the positive and negative electrode layers in Example 13 is higher than that in Comparative Example 4, respectively. Specifically, the density of the solid electrolyte layer in Examples 1-8 and 10 is ≥97%, the density of the solid electrolyte layer in Example 9 is approximately 92%, and the density of the solid electrolyte layer in Example 11 is approximately 94%. The density of the solid electrolyte layer in Comparative Examples 1 and 10 is less than 90%. The density of the positive electrode layer in Comparative Example 3 is less than 90%. The density of both the positive and negative electrode layers in Comparative Example 4 is less than 90%.

[0583] Table 2.

[0584] In Table 2, the battery internal resistance DCR test results of Examples 1-14 and Comparative Examples 1-4 are all percentages relative to the test results of Comparative Example 1.

[0585] Table 3.

[0586] In Table 3, the test data of Comparative Example 1 is 100%, and Example 1 is a percentage relative to the test data of Comparative Example 1.

[0587] The descriptions of the various implementation methods and embodiments above tend to emphasize the differences between them. Similarities or resemblances can be referenced interchangeably, and for the sake of brevity, they will not be repeated here. The technical features of the implementation methods and embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combinations of these technical features do not contradict each other, they should be considered within the scope of this specification.

[0588] It should be noted that this application is not limited to the above-described embodiments and examples. The above-described embodiments and examples are merely examples, and any embodiments and examples that have the same structure and achieve the same effect as the technical concept within the scope of this application are included in the technical scope of this application. The embodiments and examples described above only illustrate several embodiments and examples of this application, and although the descriptions are relatively detailed, they should not be construed as limiting the scope of the patent. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments or examples, and other ways of constructing embodiments or examples by combining some of the constituent elements of the embodiments or examples, are also included in the scope of this application without departing from the spirit of this application.

Claims

A solid-state battery includes a solid electrolyte layer and two electrode layers located on both sides of the solid electrolyte layer, one of which is a positive electrode layer and the other is a negative electrode layer; the positive electrode layer includes a positive electrode active material layer, and the negative electrode layer includes a negative electrode active material layer; An interface functional layer is arranged between the solid electrolyte layer and at least one of the electrode layers; the interface functional layer located between the positive electrode layer and the solid electrolyte layer is referred to as a positive electrode interface functional layer, and the interface functional layer located between the negative electrode layer and the solid electrolyte layer is referred to as a negative electrode interface functional layer; The mass percentage of the organic component in the positive electrode interface functional layer is denoted as f m1 ; the mass percentage of the organic component in the negative electrode interface functional layer is denoted as f m2 ; the mass percentage of the organic component in the positive electrode active material layer is denoted as f mP ; the mass percentage of the organic component in the negative electrode active material layer is denoted as f mN ; the mass percentage of the organic component in the solid electrolyte layer is denoted as f mE ; Wherein, when the positive electrode interface function layer is present, f m1 less than f mP and f mE at least one of when the negative electrode interface function layer is present, f m2 less than f mN and f mE at least one of. The solid-state battery according to claim 1, wherein The organic component includes one or more of an organic binder and an organic dispersant; The organic binder includes one or more of polyvinylidene fluoride, styrene-butadiene rubber emulsion, carboxymethyl cellulose, sodium carboxymethyl cellulose, sodium alginate, polyvinyl alcohol, polymethyl methacrylate, hydrogenated nitrile rubber, polytetrafluoroethylene, and polyacrylic acid; The organic dispersant includes one or more of a cationic wet dispersant, an anionic wet dispersant, and an amphoteric wet dispersant; the cationic wet dispersant includes one or more of an amine salt, a quaternary amine salt, and a pyridinium salt; the anionic wet dispersant includes one or more of a fatty acid salt, a sulfate salt, and a sulfonate salt; the amphoteric wet dispersant includes a high-molecular polymer of phosphate ester type. The solid-state battery according to claim 1 or 2, wherein The thickness of any interface functional layer is less than or equal to 50 μm. The solid-state battery according to claim 3, wherein The thickness of any interface functional layer is 1 μm to 50 μm. The solid-state battery according to any one of claims 1 to 4, wherein The solid-state battery satisfies one or both of the following characteristics: The positive electrode interface functional layer exists, f m1 <f mP And f m1 <f mE ; The negative electrode interface functional layer exists, f m2 <f mN and f m2 <f mE . The solid-state battery according to any one of claims 1 to 4, wherein The conductivity of the positive electrode interface functional layer is denoted as σ1; the conductivity of the negative electrode interface functional layer is denoted as σ2; the conductivity of the positive electrode active material layer is denoted as σ P ; the conductivity of the negative electrode active material layer is denoted as σ N ; and the conductivity of the solid electrolyte layer is denoted as σ E ; The solid-state battery satisfies one or more of the following characteristics: The positive electrode interface functional layer exists, σ1 is greater than σ P and σ E at least one of them; optionally, when σ1> σ P f m1 < f mP , when σ1> σ E f m1 < f mE ; The negative electrode interface functional layer exists, σ2 is greater than σ N and σ E at least one of; optionally, when σ2> σ N f m2 f mN , when σ2> σ E f m2 f mE . The solid-state battery according to claim 6, wherein The solid-state battery satisfies one or more of the following characteristics: The positive electrode interface functional layer exists, σ1>σ P and f m1 < f mP , or, σ1>σ E and f m1 < f mE ; The negative electrode interface functional layer exists, σ2> σ N and f m2 < f mN , or, σ2> σ E and f m2 < f mE ; The positive electrode interface functional layer exists, f m1 <f mP And f m1 <f mE , σ1>σ P And σ1>σ E ; The negative electrode interface functional layer exists, f m2 <f mN And f m2 <f mE , σ2>σ N And σ2>σ E . The solid-state battery according to any one of claims 1 to 7, wherein The interface functional layer satisfies one or both of the following characteristics: At least a portion of the interface functional layer is an extension of the adjacent electrode active material layer; At least a portion of the interface functional layer is an extension of the solid electrolyte layer. The solid-state battery according to any one of claims 1 to 8, wherein The interface functional layer includes an interface layer active material of the same type as the electrode active material in the adjacent electrode layer, and an interface layer electrolyte material of the same type as the solid electrolyte material in the solid electrolyte layer. The solid-state battery according to any one of claims 1 to 9, wherein The interface functional layer has an interlocking interface. The solid-state battery according to any one of claims 1 to 10, wherein Any interface functional layer independently includes a first sub-layer and a second sub-layer, the second sub-layer being located between the first sub-layer and the solid electrolyte layer; The first sub-layer and the adjacent electrode layer include the same type of electrode active material; The second sub-layer and the solid electrolyte layer include the same type of solid electrolyte material. The solid-state battery according to claim 11, wherein The mass fraction of the electrode active material in the first sub-layer is higher than the mass fraction of the electrode active material in the second sub-layer; the mass fraction of the solid electrolyte material in the second sub-layer is higher than the mass fraction of the solid electrolyte material in the first sub-layer. The solid-state battery according to claim 11 or 12, wherein The first sub-layer and the second sub-layer have an interlocking interface. The solid-state battery according to any one of claims 1 to 13, wherein At least one of the positive electrode active material layer and the negative electrode active material layer includes an organic component; The density of the solid electrolyte layer is denoted as K E , and satisfies K E ≥ 90%. The solid-state battery according to claim 14, wherein K E ≥97％。 The solid-state battery according to any one of claims 1 to 15, wherein The solid electrolyte layer includes an organic component, and the solid-state battery satisfies at least one of the following characteristics: (b1) the density of the positive electrode active material layer is denoted as K P , and satisfies K P ≥ 90%. (b2) the density of the negative electrode active material layer is denoted as K N , and satisfies K N ≥ 90%. The solid-state battery according to claim 16, wherein The solid-state battery satisfies at least one of the following characteristics: K P ≥97％； K N ≥97％。 The solid-state battery according to any one of claims 1 to 17, wherein The solid-state battery is a full solid-state battery. A method of manufacturing a solid-state battery, wherein The method comprises the following steps: An anode active initial layer located on at least one side surface of an anode electrode sheet is subjected to etching treatment to form an anode rough surface with anode recesses, and the anode electrode sheet after the etching treatment comprises anode protrusions corresponding to the anode recesses; wherein the anode active initial layer comprises degradable organic components; after the etching treatment, the content of the degradable organic components in the anode protrusions decreases; An electrolyte pre-coating layer is arranged on the anode rough surface, and the electrolyte pre-coating layer is subjected to pressing treatment to make the anode protrusions and the electrolyte pre-coating layer parts filled in the corresponding anode recesses jointly form anode interface functional layers, and make the remaining parts of the electrolyte pre-coating layer form a solid electrolyte layer; A cathode layer is formed on a side surface of the solid electrolyte layer away from the anode interface functional layer. The method of claim 19, wherein The density of the solid electrolyte layer is denoted as K E , and satisfies K E ≥ 90%, and the etching depth is 1 μm to 50 μm. The method of claim 20, wherein K E ≥ 97%, with an etching depth of 3-40 μm. A method of manufacturing a solid-state battery, wherein The method comprises the following steps: A cathode active initial layer located on at least one side surface of a cathode electrode sheet is subjected to etching treatment to form a cathode rough surface with cathode recesses, and the cathode electrode sheet after the etching treatment comprises cathode protrusions corresponding to the cathode recesses; wherein the cathode active initial layer comprises degradable organic components; after the etching treatment, the content of the degradable organic components in the cathode protrusions decreases; An electrolyte pre-coating layer is arranged on the cathode rough surface, and the electrolyte pre-coating layer is subjected to pressing treatment to make the cathode protrusions and the electrolyte pre-coating layer parts filled in the corresponding cathode recesses jointly form cathode interface functional layers, and make the remaining parts of the electrolyte pre-coating layer form a solid electrolyte layer; A anode layer is formed on a side surface of the solid electrolyte layer away from the cathode interface functional layer. The method of claim 22, wherein K E ≥ 90%, with an etching depth of 1 μm to 50 μm. The method of claim 23, wherein K E ≥ 97%, with an etching depth of 3-40 μm. A method for preparing a solid-state battery comprises the following steps: A solid electrolyte film is provided comprising first and second surfaces facing away from each other; wherein The solid electrolyte film comprises degradable organic components; A first surface of the solid electrolyte film is subjected to etching treatment to form a first rough surface with first recesses, and the solid electrolyte film after the etching treatment comprises first protrusions corresponding to the first recesses; after the etching treatment, the content of the degradable organic components in the first protrusions decreases; A first electrode pre-coating layer is arranged on the first surface of the solid electrolyte film after the etching treatment, and the first electrode pre-coating layer is subjected to pressing treatment to make the first protrusions and the first electrode pre-coating layer parts filled in the corresponding first recesses jointly form first interface functional layers, and make the remaining parts of the first electrode pre-coating layer form a first electrode layer; A second electrode layer is formed on a second surface of the solid electrolyte film. The method of claim 25, wherein The method for forming a second electrode layer on a second surface of a solid electrolyte film comprises the following steps: The second surface of the solid electrolyte film is subjected to etching treatment to form a second rough surface with second recesses, and the solid electrolyte film after the etching treatment comprises second protrusions corresponding to the second recesses; After the etching treatment, the content of the degradable organic components in the second protrusions decreases; After the etching treatment, the content of the degradable organic components in the second protrusions decreases; A second electrode pre-coating layer is provided on a second surface of the solid electrolyte membrane after the etching treatment, and a pressing treatment is performed on the second electrode pre-coating layer to make the second protrusions and the portions of the second electrode pre-coating layer filled in the corresponding second recesses jointly form a second interfacial functional layer, and make the remaining portions of the second electrode pre-coating layer form the second electrode layer. The method of producing a solid-state battery according to claim 25 or 26, wherein The first electrode layer is a positive electrode layer, or the first electrode layer is a negative electrode layer. The method of claim 27, wherein The solid electrolyte membrane is subjected to etching treatment on a side surface close to the positive electrode layer before the positive electrode layer is formed P , and the density of the positive electrode layer is denoted as K P ≥ 90%, and the etching depth is 1 μm to 50 μm. The method of claim 28, wherein K P ≥ 97%, with an etching depth of 3-40 μm. The method of claim 27, wherein The solid electrolyte membrane is subjected to etching treatment on a side surface close to the negative electrode layer before the negative electrode layer is formed N , and the density of the negative electrode layer is denoted as K N ≥ 90%, and the etching depth is 1 μm to 50 μm. The method of claim 30, wherein K N ≥ 97%, with an etching depth of 3-40 μm. The method of producing a solid-state battery according to any one of claims 19 to 31, wherein The etching method for performing the etching treatment includes one or more of a plasma treatment and a laser treatment. An electric device including at least one of the solid-state batteries of any one of claims 1-18 and the solid-state batteries prepared by the preparation method of any one of claims 19-32.

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