All-solid-state battery and preparation method and application thereof

Abstract

The application discloses a kind of all-solid-state batteries and preparation method and application thereof, it is related to solid-state battery technical field.The all-solid-state battery provided in the application uses halide and oxyhalide with certain electrochemical activity as solid electrolyte, by limiting the volume ratio between electrolyte and positive electrode layer and interface engineering regulation and control between the two, the specific capacity of the obtained battery is greatly improved, the all-solid-state battery provided in the application can reach 312 mAh / g or more according to the mass of positive electrode active material, the discharge specific capacity can reach 202 mAh / g or more according to the total mass of positive electrode, without increasing battery components and battery thickness, the capacity of battery can be effectively improved, so as to improve the energy density of all-solid-state battery.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery technology, specifically to an all-solid-state battery, its preparation method, and its application. Background Technology

[0002] With the surge in demand for high-energy-density and high-safety energy storage devices from industries such as electric vehicles and portable electronic devices, all-solid-state batteries are considered a core direction for next-generation battery technology due to their theoretical energy density exceeding 500 Wh / kg and the use of safe solid-state electrolytes instead of flammable organic liquid electrolytes. However, the actual energy density of existing all-solid-state batteries is generally less than 300 Wh / kg, far below expectations. The main factors determining the energy density of solid-state batteries include the intrinsic properties of the electrode active materials, the intrinsic properties of the electrolyte materials, and the interfacial properties between the two.

[0003] The existing all-solid-state battery has a "sandwich" structure, consisting of a positive electrode material, a solid electrolyte, and a negative electrode material stacked together. However, due to the low ionic conductivity of traditional positive electrode materials and the weak wetting effect between the solid electrolyte and the positive electrode material, the positive electrode material needs to be mixed with a large amount of solid electrolyte before assembling the solid-state battery to ensure that the resulting composite positive electrode has sufficient electronic and ionic conductivity. However, solid electrolytes are usually inactive materials, which leads to the dilution of the concentration of positive electrode active material in the composite positive electrode and a significant reduction in the loading, making it impossible to achieve a high-energy-density all-solid-state battery. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an all-solid-state battery with significantly improved specific capacity through interface engineering control. Furthermore, the present invention also provides a method for preparing the all-solid-state battery and its applications.

[0005] The above-mentioned objective of this invention is achieved through the following technical solution:

[0006] An all-solid-state battery includes a composite positive electrode and a negative electrode. The composite positive electrode includes a positive electrode material layer and an electrolyte layer. The raw material for preparing the electrolyte layer includes an active electrolyte. The active electrolyte includes at least one of an active halide electrolyte and an active halide oxide electrolyte.

[0007] In the composite cathode, the volume ratio of the cathode material layer to the electrolyte layer is ≤1:2;

[0008] The surface of the positive electrode material layer near the electrolyte layer has several protrusions; the surface of the electrolyte layer near the positive electrode material layer has several recesses; the protrusions on the surface of the positive electrode material layer are adapted to the recesses on the surface of the electrolyte layer.

[0009] The depth of the recesses on the surface of the electrolyte layer is 10% to 50% of the thickness of the electrolyte layer, and the area ratio of the plurality of recesses on the surface of the electrolyte layer satisfies the following relationship:

[0010] S1 / S2 = 40%~60%;

[0011] Wherein, S1 is the sum of the cross-sectional areas of the plurality of recessed openings, and S2 is the area of ​​the electrolyte layer surface near the positive electrode material layer before the recesses are provided.

[0012] Through extensive experimental research, the inventors of this application discovered that active halides and active halide oxides, as solid-state electrolytes, possess certain electrochemical activity. They can undergo reversible valence-changing reactions during charging and discharging, providing additional capacity to the battery. Simultaneously, they can also provide ion channels as solid-state electrolytes. By selecting these electrolytes with high ionic conductivity and electronic insulation to form a composite cathode with conventional cathode layers, greater reversible capacity can be achieved with the same cathode material loading, thereby improving the battery's specific capacity and energy density.

[0013] It should be noted that the inventors of this application discovered in experiments that in order to fully improve the electrochemical activity and specific capacity of the selected solid electrolyte, it is necessary to control the volume ratio between the cathode material and the electrolyte layer. If the proportion of the electrolyte layer is too low, it cannot provide enough additional capacity for the resulting all-solid-state battery, resulting in a decrease in the capacity of the all-solid-state battery.

[0014] To fully utilize the electrolyte layer, this invention also requires interface engineering control of the interface between the electrolyte layer and the positive electrode material layer. This involves creating matching recesses and protrusions (the size and depth of corresponding recesses and protrusions in the electrolyte and positive electrode layers must match) to increase the contact area between them. In the interface engineering of this invention, the depth of the recesses on the electrolyte layer surface should not be less than 10% of the electrolyte layer thickness; otherwise, a tight interlocking bond cannot be formed between the positive electrode material layer and the electrolyte layer, failing to reduce interface resistance and also hindering the increase of the contact area. If the recess depth is too high, the positive electrode material cannot be deeply embedded into the recess, resulting in gaps at the interface between the positive electrode material layer and the electrolyte layer, which increases the battery's internal resistance, reduces ion transport efficiency, and accelerates battery performance degradation. Typical, but not limiting, recess depths are 10%, 15%, 18%, 20%, 25%, 30%, 40%, and 50% of the electrolyte layer thickness.

[0015] Building upon the premise that a specific depth of the recesses ensures sufficient contact between the two layers, the area ratio of all recesses in the electrolyte layer is further defined. This area ratio represents the distribution of the cathode material between the electrolyte layers, thereby ensuring good contact between the two layers, fully utilizing the electrochemical activity of the electrolyte layer, and improving the utilization rate of the active electrolyte. A ratio that is too high or too low for the sum of the cross-sectional areas of the recesses to the area of ​​the electrolyte layer (before the recesses are installed) will lead to a decrease in the utilization rate of the active electrolyte. Typical but non-limiting S1 / S2 ratios are 40%, 45%, 50%, 55%, and 60%.

[0016] In a specific embodiment of the present invention, the area ratio of all concave holes on the surface of the electrolyte layer can be adjusted by changing the shape, diameter, and spacing of the concave holes.

[0017] In a specific embodiment of the present invention, the composite positive electrode has a positive electrode material layer thickness of 5-150 μm and an electrolyte layer thickness of 400-600 μm. More specifically, the thickness of the positive electrode material layer excludes the protruding portions.

[0018] In a specific embodiment of the present invention, the composite positive electrode comprises a positive electrode material layer and an electrolyte layer stacked sequentially. More specifically, the projected areas of the positive electrode material layer and the electrolyte layer on the stacked plane are equal (i.e., without considering protrusions and recesses, the area of ​​the positive electrode material layer projected onto the stacked plane is equal to the area of ​​the electrolyte layer projected onto the stacked plane), therefore, the volume ratio of the two can be replaced by the thickness ratio of the two.

[0019] Preferably, the volume ratio of the positive electrode material layer to the electrolyte layer in the composite positive electrode is (0.02~1):2.

[0020] More preferably, the volume ratio of the positive electrode material layer to the electrolyte layer in the composite positive electrode is (0.1~0.8):2.

[0021] Preferably, the active halide electrolyte includes Li x V y Cl6, Li x Ti y Cl6, Li x Fe y Cl4, Li x Ta y Cl6, Li x Nb y Cl6, Li x Nb y Ta z At least one of Cl6;

[0022] The Li x V yIn Cl6, 0 < x < 4, 1 ≤ y ≤ 1.5;

[0023] The Li x Ti y In Cl6, 0 < x < 4, 1 ≤ y ≤ 1.5;

[0024] The Li x Fe y In Cl4, 0 < x ≤ 2, 1 ≤ y < 2;

[0025] The Li x Ta y In Cl6, 0<x<4, 0<y<2;

[0026] The Li x Nb y In Cl6, 0<x<4, 0<y<2;

[0027] The Li x Nb y Ta z In Cl6, 0<x<4, 0<y<2, 0<z<2.

[0028] Typical but non-restrictive Li x V y Cl6 includes Li3VCl6.

[0029] Typical but non-restrictive Li x Ti y Cl6 includes Li3TiCl6.

[0030] Typical but non-restrictive Li x Fe y Cl4 includes Li2FeCl4.

[0031] Typical but non-restrictive Li x Ta y Cl6 includes LiTaCl6.

[0032] Typical but non-restrictive Li x Nb y Cl6 includes LiNbCl6.

[0033] Typical but non-restrictive Li x Nb y Ta z Cl6 includes LiNb 0.5 Ta 0.5 Cl6.

[0034] Preferably, the active halide oxide electrolyte includes Li x Nb y OCl4, Lix Ta y OCl4, Li x Nb y Ta z At least one of OCl4;

[0035] The Li x Nb y In OCl4, 0<x<4, 0<y<2;

[0036] The Li x Ta y In OCl4, 0<x<4, 0<y<2;

[0037] The Li x Nb y Ta z In OCl4, 0<x<4, 0<y<2, 0<z<2.

[0038] Typical but non-restrictive Li x Nb y OCl4 includes LiNbOCl4.

[0039] Typical but non-restrictive Li x Ta y OCl4 includes LiTaOCl4.

[0040] Typical but non-restrictive Li x Nb y Ta z OCl4 includes LiNb 0.5 Ta 0.5 OCl4.

[0041] The aforementioned halides and halide oxides are electrochemically active electrolytes obtained by the inventors of this application through extensive experimental verification. Other commonly used electrolytes in this field include Li3YCl6 and Li... 1.75 ZrO 0.5 Cl 4.75 The inventors of this application have verified that these electrolytes do not have electrochemical activity and therefore do not belong to active halide electrolytes or active halide oxide electrolytes.

[0042] More preferably, the active electrolyte includes an active halide oxide electrolyte.

[0043] Preferably, the opening of the concave hole is a circle with a diameter of 0.02~0.06 mm.

[0044] If the opening diameter of the concave pore is too small, the positive electrode material particles will have difficulty fully penetrating into the electrolyte layer. If the pore diameter is too large, the positive electrode material will easily agglomerate.

[0045] In a specific embodiment of the present invention, the diameters of all the openings of the recesses on the surface of the electrolyte layer are equal or similar (error ≤ 1%).

[0046] Preferably, the spacing between the recessed holes is 0.05~0.1 mm.

[0047] If the hole spacing is too large, it means that the hole diameter may be too small when it is necessary to ensure that S1 / S2 = 40%~60%; and vice versa. Therefore, this application also prefers the hole spacing of the concave holes to be 0.05~0.1 mm.

[0048] In a specific embodiment of the present invention, the hole spacing refers to the distance between the edges of two adjacent holes.

[0049] Preferably, the recesses are regularly arranged on the surface of the electrolyte layer.

[0050] In a specific embodiment of the present invention, the recesses are distributed on the surface of the electrolyte layer in a square arrangement. That is, the line connecting the centers of any two adjacent recesses is one side of a square.

[0051] In a specific embodiment of the present invention, S1 = nπ(1 / 2 × d) 2 Where n is the number of recesses on the electrolyte layer surface, and d is the diameter of the cross-section of the circular recess. Changes in the pore diameter and the spacing between pores will cause changes in the number of recesses n that can be placed on the electrolyte layer plane.

[0052] Preferably, the depth of the recesses on the surface of the electrolyte layer is 20% to 30% of the thickness of the electrolyte layer.

[0053] Preferably, the positive electrode material layer comprises the following raw materials in parts by weight:

[0054] 60-100 parts positive electrode active material, 0-30 parts active electrolyte, 0-10 parts conductive agent, 0-5 parts binder.

[0055] In all-solid-state batteries, the raw materials for preparing the positive electrode material typically also include a solid electrolyte. In this invention, because the selected specific solid electrolyte possesses electrochemical activity, the addition of an active electrolyte to the raw materials for preparing the positive electrode material layer allows it to function as an active material, while also exhibiting good high voltage stability, high ionic conductivity, and electronic insulation, thereby further and effectively increasing the proportion of active material in the all-solid-state battery.

[0056] More preferably, the total mass fraction of all raw materials used in the preparation of the positive electrode material layer is 60-145 parts.

[0057] More preferably, the positive electrode active material includes LiCoO2, LiFePO4, LiMn2O4, and LiNi.x Co y Mn z O2、xLi2MnO3·(1-x)LiNi a Co b Mn c At least one of O2, Li2S, Mo6S8, and TiS2.

[0058] In a specific embodiment of the present invention, the LiNi x Co y Mn z In O2, x + y + z = 1. Typical but non-restrictive LiNi x Co y Mn z O2 materials include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2.

[0059] In a specific embodiment of the present invention, the xLi2MnO3·(1-x)LiNi a Co b Mn c In O2, 0 < x < 1, a + b + c = 1. A typical but non-restrictive example is xLi2MnO3·(1-x)LiNi. a Co b Mn c O2 materials include 0.5Li2MnO3·0.5LiNi 1 / 3Co 1 / 3 Mn 1 / 3 O2, 0.5Li2MnO3·0.5LiNi 0.5 Co 0.2 Mn 0.3 O2.

[0060] More preferably, the conductive agent includes at least one of conductive carbon black, VGCF (vapor-grown carbon fiber), acetylene black, Ketjen black, carbon nanotubes, and graphene.

[0061] More preferably, the adhesive includes at least one of polytetrafluoroethylene, polyamide, polyester, and vinyl acetate copolymer.

[0062] Preferably, the negative electrode includes a buffer layer and a lithium-containing active material.

[0063] In a specific embodiment of the present invention, the thickness of the negative electrode is 55~250μm.

[0064] In a specific embodiment of the present invention, the all-solid-state battery includes a composite positive electrode and a negative electrode stacked sequentially. More specifically, the composite positive electrode and the negative electrode have equal projected areas on the plane in which they are stacked.

[0065] More preferably, the raw materials for preparing the buffer layer include at least one of halide solid electrolyte, sulfide solid electrolyte, nitride solid electrolyte, hydride solid electrolyte, and anti-perovskite solid electrolyte.

[0066] More preferably, the halide solid electrolyte includes Li3YCl6, Li3YbCl6, Li3LuCl6, and Li3YCl. 4.5 Br 1.5 At least one of them.

[0067] More preferably, the sulfide solid electrolyte includes Li6PS5Cl and Li 10 GeP2S 12 Li7P3S 11 At least one of them.

[0068] More preferably, the nitride solid electrolyte includes Li3N, and the Li3N includes at least one of α-Li3N and β-Li3N.

[0069] More preferably, the hydride solid electrolyte includes LiBH4 and / or its derivatives.

[0070] More preferably, the anti-perovskite solid electrolyte includes at least one of Li3OCl, Li2OHCl, Li2OHBr and their derivatives.

[0071] More preferably, the negative electrode lithium-containing active material includes at least one of lithium metal, lithium-rich alloy, and lithium-carbon material.

[0072] More preferably, the lithium-rich alloy includes a lithium-indium alloy (Li). x In, Lithium-silicon alloy Li x At least one of Si, lithium-aluminum alloy, lithium-tin alloy, lithium-magnesium alloy, and lithium-zinc alloy.

[0073] More preferably, the lithium-carbon material includes LiC. x Lithium-carbon composites.

[0074] More preferably, the volume ratio of the buffer layer to the lithium-containing active material in the negative electrode is (15~45):(2~5).

[0075] In a specific embodiment of the present invention, the negative electrode comprises a buffer layer and a lithium-containing active material stacked sequentially. More specifically, the all-solid-state battery comprises a positive electrode material layer, an electrolyte layer, a buffer layer, and a lithium-containing active material stacked sequentially. More specifically, the positive electrode material layer, the electrolyte layer, the buffer layer, and the lithium-containing active material have equal projected areas on the stacked plane.

[0076] In a specific embodiment of the present invention, the thickness of the buffer layer is 50~150μm.

[0077] In a specific embodiment of the present invention, the thickness of the lithium-containing active material in the negative electrode is 5~100μm.

[0078] Preferably, the all-solid-state battery further includes a positive current collector and a negative current collector.

[0079] In specific embodiments of the present invention, the positive electrode current collector can be selected from conventional positive electrode current collectors in the art, including positive electrode metal current collectors and / or positive electrode composite current collectors. More specifically, the positive electrode metal current collector includes aluminum foil and / or nickel foil. More specifically, the positive electrode composite current collector includes at least one of metal and carbon material composite foil, polymer and conductive material composite foil, plant fiber composite foil, and polymer and metal material composite foil.

[0080] In specific embodiments of the present invention, the negative electrode current collector can be selected from conventional negative electrode current collectors in the art, including negative electrode metal current collectors and / or negative electrode composite current collectors. More specifically, the negative electrode metal current collector includes copper foil and / or nickel foil. More specifically, the negative electrode composite current collector includes at least one of metal and carbon material composite foil, polymer and conductive material composite foil, plant fiber composite foil, and polymer and metal material composite foil.

[0081] In a specific embodiment of the present invention, the all-solid-state battery includes a positive current collector, a composite positive electrode, a negative electrode, and a negative current collector stacked sequentially.

[0082] This invention also protects a method for preparing the above-mentioned all-solid-state battery, comprising the following steps:

[0083] S1. Mix the raw materials for preparing the cathode material layer in a certain proportion to obtain the cathode material;

[0084] S2. The active electrolyte is shaped to obtain an electrolyte layer. The surface of the electrolyte layer is etched to obtain an electrolyte layer with several channels on the surface. Then, the positive electrode material obtained in step S1 is coated on its surface to obtain a composite positive electrode.

[0085] S3. Assemble the composite positive and negative electrodes to obtain an all-solid-state battery.

[0086] Preferably, the mixing in step S1 is carried out in an inert atmosphere.

[0087] Preferably, the mixing in step S1 is performed by ball milling, and the ball milling speed is 100~600 rpm.

[0088] Preferably, the molding in step S2 includes cold pressing, and the pressure of the cold pressing is 200~500 MPa.

[0089] Preferably, the etching in step S2 includes laser etching.

[0090] Pulsed lasers have no heat-affected zone, and halide oxides have a lower melting point than other electrolyte materials. Laser ablation on the halide oxide interface layer makes it easier to precisely process the target structure without affecting the non-processed areas. This helps the electrode layer and the solid electrolyte to interlock tightly, which can significantly reduce the interface resistance and improve the utilization rate of the active material in the interface layer. As a result, the all-solid-state battery based on this integrated cathode has advantages such as high specific capacity, high energy density, and high safety.

[0091] More preferably, the power of the laser etching in step S2 is 10. 6 ~10 8 W / cm 2 The frequency is 20~80 kHz, and the fill spacing is 0.05~0.1 mm.

[0092] More preferably, step S2 further includes a cold pressing step after coating.

[0093] More preferably, the pressure of the cold pressing is 300~600 MPa.

[0094] More preferably, step S3 further includes a packaging step after assembly.

[0095] The encapsulation includes covering the block obtained after assembling the composite positive and negative electrodes with an aluminum alloy.

[0096] More preferably, the encapsulation process further includes a pressurization step, wherein the pressurization includes: applying pressure to the encapsulated body in a direction perpendicular to the interface between the positive electrode material layer and the electrolyte layer, wherein the pressure applied is 50~100MPa.

[0097] The purpose of applying pressure is to promote the bonding between different material layers.

[0098] It should be noted that after the molding in step S2 in this application, each layer has been compressed and compacted. Therefore, the subsequent cold pressing and pressure application will have a negligible impact on the thickness of each layer and need not be considered.

[0099] This invention also protects the application of the above-mentioned all-solid-state batteries in energy storage devices, electric vehicles, and portable electronic devices.

[0100] Compared with the prior art, the present invention has the following beneficial effects:

[0101] The all-solid-state battery provided by this invention has excellent specific capacity. Calculated by the mass of the positive electrode active material, the discharge specific capacity can reach more than 312 mAh / g, and calculated by the total mass of the positive electrode, the discharge specific capacity can reach more than 202 mAh / g. Attached Figure Description

[0102] Figure 1 This is a schematic diagram of the structure of the all-solid-state battery provided by the present invention, wherein 1-positive electrode current collector, 2-composite positive electrode, 21-positive electrode material layer, 22-electrolyte layer, 3-negative electrode buffer layer, 4-negative electrode lithium-containing active material, and 5-negative electrode current collector.

[0103] Figure 2 This is an enlarged view of the interface details between the positive electrode material layer and the electrolyte layer of the all-solid-state battery provided by the present invention, where 6 is the depth of the recess, 61 is the diameter of the recess cross-section, and 62 is the spacing between the recesses.

[0104] Figure 3 This is a charge-discharge curve of the all-solid-state battery for the first three cycles provided in Embodiment 1 of the present invention.

[0105] Figure 4 This is a charge-discharge curve of the all-solid-state battery for the first three cycles provided in Comparative Example 9 of the present invention. Detailed Implementation

[0106] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0107] Examples 1-8 and Comparative Examples 1-8

[0108] This embodiment and comparative examples provide a series of all-solid-state batteries with different volume ratios of the positive electrode material layer to the electrolyte layer and different surface pore structures of the electrolyte layer. The all-solid-state batteries include composite positive and negative electrodes.

[0109] The composite cathode comprises a cathode material layer with a thickness of 6-200 μm and an electrolyte layer with a thickness of approximately 300-544 μm, stacked sequentially (the projected area of ​​both layers on the stacked plane is 0.785 cm²). 2 The raw materials for preparing the positive electrode material layer include the following components in parts by weight: 65 parts LiCoO2, 30 parts LiNbOCl4, 3 parts VGCF, and 2 parts PTFE.

[0110] The raw materials for preparing the electrolyte layer include the active electrolyte LiNbOCl4;

[0111] The volume ratio (i.e., thickness ratio) of the positive electrode material layer to the electrolyte layer in the composite positive electrode is (0~67):100. The positive electrode material layer has several protrusions on its surface near the electrolyte layer, and the electrolyte layer has several recesses on its surface near the positive electrode material layer. The protrusions on the surface of the positive electrode material layer and the recesses on the surface of the electrolyte layer are matched. The recesses have circular openings (the recesses are cylindrical), a diameter of 0~0.1 mm, a depth of 0~400 μm (0%~80% of the electrolyte layer thickness), and a spacing of 0~0.2 mm. The recesses satisfy S1 / S2=0%~96%, where S1 is the sum of the cross-sectional areas of the openings of the recesses, and S2 is the area of ​​the electrolyte layer surface near the positive electrode material layer before the recesses are provided.

[0112] The negative electrode comprises a 200 μm thick buffer layer and a 50 μm thick lithium-containing active material, stacked sequentially. The buffer layer is prepared from Li3YCl6 electrolyte, and the lithium-containing active material is a lithium-indium alloy Li. x In;

[0113] The structure of the all-solid-state battery is as follows: a positive electrode material layer, an electrolyte layer, a negative electrode buffer layer, and a negative electrode lithium-containing active material are stacked in sequence.

[0114] The preparation method of the all-solid-state battery in this embodiment and the comparative example includes the following steps:

[0115] S1. The raw materials for preparing the cathode material layer are mixed in proportion in an argon atmosphere and ball-milled at 400 rpm to obtain the cathode material;

[0116] S2. LiNbOCl4 powder was cold-pressed at 300 MPa to obtain an electrolyte layer. The surface of the electrolyte layer was then etched using a fiber pulsed laser with a laser etching power of 3 × 10⁻⁶. 6 W / cm 2 The frequency is 40KHz and the filling spacing is 0.05mm. After etching, an electrolyte layer with several channels on the surface is obtained. Then, the positive electrode material obtained in step S1 is coated on its surface to form a positive electrode material layer. After cold pressing at 500 MPa, a composite positive electrode can be obtained.

[0117] S3. A Li3YCl6 electrolyte is covered on the surface of the electrolyte layer in the composite positive electrode as a negative electrode buffer layer, and then a lithium indium alloy is covered on the surface of the negative electrode buffer layer. The battery is assembled by applying a pressure of 50 MPa.

[0118] The variables involved in the all-solid-state batteries provided in the examples and comparative examples are shown in Table 1 below:

[0119] Table 1. Differences between the all-solid-state batteries in the examples and comparative examples

[0120]

[0121] Note: In Table 1 above, "area ratio of concave holes" refers to S1 / S2, where S1 is the sum of the cross-sectional areas of all concave holes, and S2 is the projected area of ​​the electrolyte layer surface near the positive electrode material layer.

[0122] The structure of the all-solid-state battery provided in Example 1 is as follows: Figure 1-2 As shown: Figure 1 In the diagram, 1 represents the positive electrode current collector, 2 represents the composite positive electrode, where 21 is the positive electrode material layer, 22 is the electrolyte layer, 3 is the negative electrode buffer layer, 4 is the negative electrode lithium-containing active material, and 5 is the negative electrode current collector. Figure 2 This is an enlarged view of the interface details between the positive electrode material layer and the electrolyte layer of the all-solid-state battery provided by the present invention, where 6 is the depth of the recess, 61 is the diameter of the recess cross-section, and 62 is the spacing between the recesses.

[0123] Example 9

[0124] An all-solid-state battery, which differs from Example 1 only in that:

[0125] The raw materials for preparing the cathode material layer include 65 parts of LiCoO2, 23 parts of LiNbOCl4, 10 parts of VGCF and 2 parts of PTFE.

[0126] The preparation method of the all-solid-state battery in this embodiment is carried out according to Example 1.

[0127] Example 10

[0128] An all-solid-state battery, which differs from Example 1 only in that:

[0129] The raw materials for preparing the cathode material layer include 80 parts of LiCoO2, 15 parts of LiNbOCl4, 3 parts of VGCF and 2 parts of PTFE.

[0130] The preparation method of the all-solid-state battery in this embodiment is carried out according to Example 1.

[0131] Example 11

[0132] An all-solid-state battery, which differs from Example 1 only in that:

[0133] The raw materials for preparing the cathode material layer include 90 parts of LiCoO2, 5 parts of LiNbOCl4, 3 parts of VGCF and 2 parts of PTFE.

[0134] The preparation method of the all-solid-state battery in this embodiment is carried out according to Example 1.

[0135] Example 12

[0136] An all-solid-state battery, which differs from Example 1 only in that:

[0137] The raw materials for preparing the electrolyte layer include the active electrolyte LiTaOCl4.

[0138] The preparation method of the all-solid-state battery in this embodiment is carried out according to Example 1.

[0139] Example 13

[0140] An all-solid-state battery, which differs from Example 1 only in that:

[0141] The raw materials for preparing the electrolyte layer include the active electrolyte LiNbCl6.

[0142] The preparation method of the all-solid-state battery in this embodiment is carried out according to Example 1.

[0143] Example 14

[0144] An all-solid-state battery, which differs from Example 1 only in that:

[0145] The raw materials for preparing the electrolyte layer include the active electrolyte LiTaCl6.

[0146] The preparation method of the all-solid-state battery in this embodiment is carried out according to Example 1.

[0147] Comparative Example 9

[0148] An all-solid-state battery, which differs from Example 1 only in that:

[0149] The raw materials for preparing the electrolyte layer include Li3YCl6.

[0150] The preparation method of the all-solid-state battery in this comparative example is carried out according to Example 1.

[0151] Comparative Example 10

[0152] An all-solid-state battery, which differs from Example 1 only in that:

[0153] The raw materials for preparing the electrolyte layer include Li 1.75 ZrO 0.5 Cl 4.75 .

[0154] The preparation method of the all-solid-state battery in this comparative example is carried out according to Example 1.

[0155] Performance testing

[0156] Discharge specific capacity test: The all-solid-state batteries obtained in the examples and comparative examples were connected to the Blue Electric CT3002A battery charging and discharging equipment for discharge specific capacity test, and the data of the third cycle after the start of the test was taken as the standard.

[0157] Specific performance test data are shown in Table 2 below. Figures 3-4 As shown:

[0158] Table 2. Performance test data of all-solid-state batteries obtained from the examples and comparative examples.

[0159]

[0160] As can be seen from the data in Table 2 above, the all-solid-state battery provided by this invention has excellent specific capacity. Calculated based on the mass of the positive electrode active material, the discharge specific capacity can reach more than 312 mAh / g, and calculated based on the total mass of the positive electrode, the discharge specific capacity can reach more than 202 mAh / g.

[0161] As can be seen from the data in Examples 1-3 and Comparative Example 4 in Table 2, the volume ratio of the cathode material layer to the electrolyte layer in the composite cathode of this application must be ≤1:2 to ensure that the electrolyte layer can provide sufficient additional capacity for the resulting all-solid-state battery and improve the specific capacity of the all-solid-state battery. Comparative Example 4 is a commonly used scheme to improve the capacity of all-solid-state batteries (i.e., to maximize the thickness and volume of the cathode while making the electrolyte as thin and small as possible to fully utilize the cathode's function). As can be seen from the data in Comparative Example 4, this approach cannot fully utilize the additional capacity provided by the electrolyte layer, so the capacity of the resulting all-solid-state battery is insufficient. At the same time, comparing the data of Examples 1-3, it can be seen that the proportion of the electrolyte layer should not be too high. When the volume ratio of the cathode material layer to the electrolyte layer is within the preferred range of (0.1~0.8):2 in this invention (Examples 1-2), the capacity of the resulting battery is higher.

[0162] Data from Examples 1, 4-5, 8, and Comparative Examples 1-3 show that introducing recesses on the electrolyte layer surface, with a depth of 10% to 50% of the electrolyte layer thickness, ensures sufficient contact between the electrolyte layer and the positive electrode material layer. If the depth of the recesses on the electrolyte layer surface is less than 10% of the electrolyte layer thickness (Comparative Example 3), a tight interlocking bond between the positive electrode material layer and the electrolyte layer is difficult to form, failing to reduce interfacial resistance and also hindering the increase in contact area. If the recess depth is too high (Comparative Example 2), the positive electrode material cannot be deeply embedded into the recesses, resulting in gaps at the interface between the positive electrode material layer and the electrolyte layer, which increases the battery's internal resistance, reduces ion transport efficiency, and accelerates battery performance degradation. Comparing the data from Examples 1, 4-5, and 8, it is evident that when the recess depth on the electrolyte layer surface is 20% to 30% of the electrolyte layer thickness (Example 1), it better promotes contact between the electrolyte layer and the positive electrode material layer, significantly improving capacity.

[0163] As can be seen from Examples 6-7 and Comparative Examples 5-8, the area ratio of the concave holes on the surface of the electrolyte layer can be adjusted by adjusting the pore diameter and pore spacing. However, when the area ratio of the concave holes does not meet the condition of S1 / S2=30%~70% in this application, it is impossible to fully promote the contact between the electrolyte layer and the positive electrode material layer, resulting in the separate aggregation of the electrolyte and the positive electrode material, which reduces the utilization rate of the active material.

[0164] As can be seen from Examples 12-14 and Comparative Examples 9-10, using inactive electrolyte materials to construct the electrolyte layer makes it impossible to utilize the active electrolyte to provide additional capacity for the positive electrode, thus failing to improve the specific capacity of the all-solid-state battery.

[0165] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An all-solid battery, characterized by, The composite positive electrode and the negative electrode comprise a positive electrode material layer and an electrolyte layer, and the preparation raw material of the electrolyte layer comprises an active electrolyte, which comprises at least one of an active halide electrolyte, an active halide-oxygen electrolyte, and the volume ratio of the positive electrode material layer to the electrolyte layer in the composite positive electrode is (0.1-0.8):

2. The positive electrode material layer is provided with a plurality of protrusions near the surface of the electrolyte layer; the electrolyte layer is provided with a plurality of concave holes near the surface of the positive electrode material layer; the plurality of protrusions on the surface of the positive electrode material layer are matched with the plurality of concave holes on the surface of the electrolyte layer. The depth of the concave holes on the surface of the electrolyte layer is 20%-30% of the thickness of the electrolyte layer, and the area ratio of the plurality of concave holes on the surface of the electrolyte layer satisfies the following relationship: S1 / S2=40%-60%; wherein S1 is the sum of the cross-sectional areas of the openings of the plurality of concave holes, and S2 is the area of the surface of the electrolyte layer on the side close to the positive electrode material layer before the concave holes are set; The opening of the concave hole is a circle with a diameter of 0.02-0.06 mm, and the hole spacing of the concave hole is 0.05-0.1 mm. The positive electrode material layer comprises the following preparation raw materials by mass: 60-100 parts of a positive electrode active material, 0-30 parts of an active electrolyte, 0-10 parts of a conductive agent, and 0-5 parts of a binder. The active halide electrolyte includes Li x Ta y Cl6, Li x Nb y Cl6, Li x Nb y Ta z Cl6 The active halogen oxide electrolyte comprises Li x Nb y at least one of Li x Ta y at least one of Li x Nb y Ta z OCl4 The Li x Ta y Cl6, 0 < x < 4, 0 < y < 2; The Li x Nb y Cl6, 0 < x < 4, 0 < y < 2; The Li x Nb y Ta z Cl6, 0 < x < 4, 0 < y < 2, 0 < z < 2; The Li x Nb y OCl4in which 0 < x < 4, 0 < y < 2; The Li x Ta y OCl4in which 0 < x < 4, 0 < y < 2; The Li x Nb y Ta z OCl4in which 0 < x < 4, 0 < y < 2, 0 < z < 2.

2. The all-solid battery according to claim 1, wherein The volume ratio of the composite positive electrode to the negative electrode is (50-80):(17-50); And / or, the negative electrode comprises a buffer layer and a negative electrode lithium-containing active material.

3. The all-solid battery according to claim 2, wherein The positive active material includes at least one of LiCoO2, LiFePO4, LiMn2O4, LiNi x Co y Mn z O2, xLi2MnO3·(1-x)LiNi a Co b Mn c O2, Li2S, Mo6S8, TiS2.

4. The all-solid battery according to claim 1, wherein The preparation raw material of the buffer layer comprises at least one of a halide solid-state electrolyte, a sulfide solid-state electrolyte, a nitride solid-state electrolyte, a hydride solid-state electrolyte, and an anti-perovskite solid-state electrolyte. And / or, the negative electrode lithium-containing active material comprises at least one of lithium metal, lithium-rich alloy, and lithium-carbon material.

5. The all-solid battery according to claim 4, wherein And / or, the volume ratio of the buffer layer to the negative electrode lithium-containing active material in the negative electrode is (15-45):(2-5). The steps comprise: S1. uniformly mixing the preparation raw materials of the positive electrode material layer to obtain a positive electrode material; 6. A method of producing the all-solid battery according to any one of claims 1 to 5, characterized by, S2. forming an active electrolyte to obtain an electrolyte layer, etching the surface of the electrolyte layer to obtain an electrolyte layer with a plurality of concave holes on the surface, and then coating the positive electrode material obtained in step S1 on the surface, to obtain a composite positive electrode; S3. assembling the composite positive electrode and the negative electrode to obtain a full solid-state battery. The etching in step S2 comprises laser etching.

8. The application of the full solid-state battery in any one of claims 1-5 in energy storage equipment, electric vehicles, and portable electronic devices.

7. The method of claim 6, wherein the solid-state battery is prepared by the steps of: ​ ​ ​

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