All-solid-state batteries and their applications

Abstract

This invention provides an all-solid-state battery and its applications. [Solution] The all-solid-state battery comprises at least two first solid electrolyte layers and a second solid electrolyte layer. The two first solid electrolyte layers are provided on the positive electrode side and the negative electrode side of the all-solid-state battery, and the ionic conductivity of the first solid electrolyte layer is 1 × 10⁻¹⁰ -3 S / cm~1×10 -2 The conductivity is S / cm. The second solid electrolyte layer is provided between the two first solid electrolyte layers, and the ionic conductivity of the second solid electrolyte layer is 1 × 10⁻⁶. -3 S / cm~2×10 -2 The value is S / cm. The all-solid-state battery and its applications provided by the present invention improve the resistance of the solid electrolyte membrane in the all-solid-state battery to lithium dendrite penetration, enhance the interfacial stability between the solid electrolyte membrane and the negative electrode, thereby improving the battery's cycle performance and safety.

Description

[Technical Field]

[0001] This invention relates to the technology of batteries, and more specifically, to all-solid-state batteries and their applications. [Background technology]

[0002] All-solid-state batteries are attracting widespread attention due to their high energy density, superior safety, and robust durability, thanks to the use of solid electrolyte membranes. Among solid electrolyte membranes, sulfide solid electrolytes are widely used due to their remarkable room-temperature ionic conductivity and processability. However, in practical applications, sulfide solid electrolytes suffer from problems such as poor resistance to lithium dendrite penetration and poor interfacial stability with lithium metal anodes, which significantly limit the development of all-solid-state batteries. [Overview of the project] [Problems that the invention aims to solve]

[0003] This invention provides an all-solid-state battery and its applications. The all-solid-state battery and its applications provided by this invention improve the resistance of the solid electrolyte membrane in the all-solid-state battery to lithium dendrite penetration, enhance the interfacial safety between the solid electrolyte membrane and the negative electrode, thereby improving the battery's cycle performance and safety. [Means for solving the problem]

[0004] To solve the technical problems described above, the present invention provides an all-solid-state battery. The solid-state battery includes at least two first solid electrolyte layers and a second solid electrolyte layer. The first solid electrolyte layer is provided on the positive electrode side and the negative electrode side of the all-solid-state battery, and the ionic conductivity of the first solid electrolyte layer is 1 × 10⁻¹⁶. -3 S / cm~1×10 -2 The conductivity is S / cm. The second solid electrolyte layer is provided between the two first solid electrolyte layers, and the ionic conductivity of the second solid electrolyte layer is 1 × 10⁻⁶. -3 S / cm~2×10 -2 It is S / cm.

[0005] In one embodiment of the present invention, the first solid electrolyte layer contains a first electrolyte, and the chemical formula of the first electrolyte is Li a P 1-b M b S c O d X e where 5 < a < 6, 0 < b < 1, 1.5 < c < 5, 0 < d < 2.5, 4 < c + d < 5, 1 < e < 2, M is at least one selected from Al, Ga, In, Ti, Sc, As, Sb, Bi, As, V, or Nb, and X is at least one selected from Cl, Br, or I.

[0006] In one embodiment of the present invention, M is at least one selected from Sb, In, or Bi, X is Cl, and the value range of b is 0 < b ≤ 0.1.

[0007] In one embodiment of the present invention, the first solid electrolyte layer contains a first electrolyte, and the chemical formula of the first electrolyte is Li f P 1-g E g S w O g Q z where 5 < f < 10, 0 < g < 1, 3 < w < 6, 4 < w + g < 6, 0 < z < 2, E is at least one selected from Mg, Ca, Sr, Ba, Zn, Cr, Sn, or Pb, and Q is at least one selected from Cl, Br, or I.

[0008] In one embodiment of the present invention, E is Mg, Q is Cl, and the value range of g is 0.01 ≤ g ≤ 0.1.

[0009] In one embodiment of the present invention, the second solid electrolyte layer contains the first electrolyte and a second electrolyte, and the chemical formula of the second electrolyte is Li 10 Ge 1-i G i P2S 12 where 0 ≤ i < 1, and G is at least one selected from Si or Sn.

[0010] In one embodiment of the present invention, the content of the first electrolyte in the second solid electrolyte layer is 1 wt% to 95 wt%, and the content of the second electrolyte is 5 wt% to 99 wt%.

[0011] In one embodiment of the present invention, the thickness of the first solid electrolyte layer is 1 μm to 120 μm.

[0012] In one embodiment of the present invention, the thickness of the second solid electrolyte layer is 1 μm to 100 μm.

[0013] The present invention further provides an electronic device including the all-solid-state battery described above. [Effects of the Invention]

[0014] In summary, the present invention provides an all-solid-state battery and its applications. By improving the solid electrolyte membrane in the all-solid-state battery, the interfacial stability between the solid electrolyte membrane and the negative electrode can be increased, thereby reducing interfacial impedance and improving charge transfer efficiency. The resistance of the solid electrolyte membrane to lithium dendrite penetration can be improved, preventing short circuits in the battery and ensuring that the battery can operate stably and safely at high rates. The ionic conductivity of the solid electrolyte membrane can be increased, thereby improving the operating efficiency of the battery. Furthermore, the cycle performance of the battery can be improved, extending the battery's service life.

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings that are necessary for use in describing the embodiments are briefly introduced below. The accompanying drawings described below represent only a few embodiments of the present invention, and it is clear that those skilled in the art can obtain other embodiments based on these drawings without expending any creative effort. [Brief explanation of the drawing]

[0016] [Figure 1] This is a structural diagram of an all-solid-state battery in one embodiment of the present invention. [Figure 2] This is a process diagram for preparing the first solid electrolyte layer and the second solid electrolyte layer in one embodiment of the present invention. [Figure 3] This is a scanning electron microscope image of a solid electrolyte membrane in one embodiment of the present invention. [Figure 4] This figure shows the results of a room-temperature cycle performance test conducted on the all-solid-state battery according to Example 3 of the present invention. [Modes for carrying out the invention]

[0017] The following describes how the present invention can be implemented by specific embodiments. Those skilled in the art will readily understand other advantages and effects of the present invention from what is disclosed herein. The present invention can also be implemented or applied by other different specific embodiments. Each detail herein can be modified or altered in various ways without departing from the spirit of the invention, based on different viewpoints and applications.

[0018] It should be understood that the present invention can be implemented in different forms and should not be construed as being limited to the embodiments presented herein. Rather, these embodiments are provided to make the disclosure of the present invention thorough and complete and to fully convey the scope of the invention to those skilled in the art.

[0019] The technical solutions of the present invention will be described in more detail below in combination with embodiments. Naturally, the embodiments described are only a selection of embodiments of the present invention, not all embodiments. All other embodiments that a person skilled in the art could obtain without creative work based on embodiments of the present invention are all within the scope of the present invention.

[0020] As shown in Figure 1, the present invention provides an all-solid-state battery 10. The all-solid-state battery 10 includes, for example, a positive electrode 11, a negative electrode 12, and a solid electrolyte membrane 13. The solid electrolyte membrane 13 is provided between the positive electrode 11 and the negative electrode 12, and the solid electrolyte membrane 13 includes, for example, at least two first solid electrolyte layers 131 and a second solid electrolyte layer 132. At least one first solid electrolyte layer 131 is provided on both the positive electrode 11 side and the negative electrode 12 side, and the second solid electrolyte layer 132 is provided between the two first solid electrolyte layers 131. In the all-solid-state battery 10 provided by the present invention, both the resistance of the solid electrolyte membrane 13 to lithium dendrite penetration and the interfacial stability with the negative electrode 12 can be improved. Specifically, the first solid electrolyte layer 131 can ensure a continuous and stable lithium ion transmission channel by increasing the interfacial stability between the solid electrolyte membrane 13 and the negative electrode 12. The second solid electrolyte layer 132 consumes the generated lithium dendrites, prevents the penetration of lithium dendrites, avoids short circuits in the all-solid-state battery 10, and ensures that the all-solid-state battery 10 can still operate stably and safely even at high rates. In the present invention, the all-solid-state battery 10 is, for example, a primary battery or a secondary battery, and the secondary battery is, for example, a soft-pack type battery, a hard-shell type battery, or a cylindrical type battery, and the present invention does not limit the type and form of the all-solid-state battery 10.

[0021] Referring to Figure 1, in one embodiment of the present invention, the positive electrode 11 includes, for example, a positive electrode active material, a solid electrolyte, a conductive agent, a binder, etc. The positive electrode active material is at least one selected from, for example, lithium nickel cobalt manganese oxide (NCM), lithium nickelate (LNO), lithium manganese oxide (LMO), lithium nickel manganese oxide (LNMO), lithium cobalt oxide (LCO), or lithium nickel cobalt aluminum oxide (NCA). The solid electrolyte is, for example, a halogenated electrolyte that does not produce an exothermic reaction with the positive electrode active material, thereby increasing the safety of the battery. The conductive agent is at least one selected from, for example, conductive carbon black (Super P), nanocarbon fiber (vapor-phase carbon fiber, VGCF), acetylene black, carbon nanotube, graphene, etc. The binder is, for example, at least one selected from polytetrafluoroethylene (PTFE), polyvinylidene fluoride, polyethylene oxide, polyamide, polyacrylonitrile, polyacrylate, polyvinyl ether, polymethyl methacrylate, ethylene-propylene-diene ternary copolymer, polyhexafluoropropylene, or styrene-butadiene rubber. Of these, the present invention does not limit the mass ratio of the positive electrode active material, solid electrolyte, conductive agent, and binder, and may be selected according to the actual requirements.

[0022] Referring to Figure 1, in one embodiment of the present invention, the positive electrode active material is, for example, LiNi 0.8 Co 0.1 Mn 0.1 O2 is a halogenated electrolyte, and its chemical formula is, for example, Li 2.35 Zr 0.65 Fe 0.35 Cl5Br 0.5 I 0.5 The conductive agent includes, for example, Super P and VGCF, and the mass ratio of Super P to VGCF is, for example, 1:1. The binder is, for example, PTFE. The positive electrode active material, halogen solid electrolyte, conductive agent, and binder are uniformly mixed according to, for example, a mass ratio of 69:29:1:1, and then the positive electrode 11 is obtained by dry pressing.

[0023] Referring to Figure 1, in one embodiment of the present invention, the negative electrode 12 is, for example, lithium metal.

[0024] Referring to Figure 1, in one embodiment of the present invention, the first solid electrolyte layer 131 in the solid electrolyte membrane 13 is, for example, two layers. One first solid electrolyte layer 131 is provided on the positive electrode 11 side and one on the negative electrode 12 side, and a second solid electrolyte layer 132 is provided between the two first solid electrolyte layers 131. The thickness of the solid electrolyte membrane 13 is, for example, 5 μm to 300 μm, and the ionic conductivity is, for example, 1 × 10⁻⁶ -4 S / cm~2×10 -2 The conductivity is S / cm. By combining a multilayer solid electrolyte layer with the solid electrolyte membrane 13, the ionic conductivity of the solid electrolyte membrane 13 can be increased, thereby improving the operating efficiency of the all-solid-state battery 10. Specifically, the thickness of the first solid electrolyte layer 131 in the solid electrolyte membrane 13 is, for example, 1 μm to 120 μm, and the ionic conductivity is, for example, 1 × 10⁻¹⁶. -3 S / cm~1×10 -2 The conductivity is S / cm, the thickness of the second solid electrolyte layer 132 is, for example, 1 μm to 100 μm, and the ionic conductivity is, for example, 1 × 10⁻⁶. -3 S / cm~2×10 -2 The coefficient of friction is S / cm. By controlling the thickness of the solid electrolyte membrane 13, the first solid electrolyte layer 131, and the second solid electrolyte layer 132, the cycle performance of the all-solid-state battery 10 can be improved, thereby extending the battery's lifespan.

[0025] Referring to Figure 1, in one embodiment of the present invention, the first solid electrolyte layer 131 includes a first electrolyte. The first electrolyte is, for example, a reduction-resistant sulfide electrolyte, which can enhance the interfacial stability between the solid electrolyte membrane 13 and the negative electrode 12, ensure a continuous and stable lithium ion transmission channel, reduce interfacial impedance, and improve charge transfer efficiency. Specifically, the chemical formula of the first electrolyte is, for example, Li a P 1-b M b S c O d X e or Li f P 1-g Eg S w O g Q z It is at least one selected from the like. Among them, Li a P 1-b M b S c O d X e Among them, 5 < a < 6, 0 < b < 1, 1.5 < c < 5, 0 < d < 2.5, 4 < c + d < 5, 1 < e < 2, M is at least one selected from Al, Ga, In, Ti, Sc, As, Sb, Bi, As, V, or Nb, etc., and X is at least one selected from Cl, Br, or I, etc. Further, M is at least one selected from Sb, In, or Bi, etc., X is Cl, and the value range of b is, for example, 0 < b ≦ 0.1. More specifically, when M is a +5 valence element, for example, b is 0.04. When M is a +3 valence element, for example, b is 0.02. By controlling the types of M and X elements and the value range of b in the first electrolyte, the cycle performance of the all-solid-state battery 10 can be enhanced, thereby extending the service life of the battery.

[0026] [[ID=2!]] Referring to FIG. 1, in one embodiment of the present invention, when the chemical formula of the first electrolyte is Li f P 1-g E g S w O g Q[[ID=3!]] z where 5 < f < 10, 0 < g < 1, 3 < w < 6, < w + g < 6, 0 < < 2, E is at least one selected from Mg, Ca, Sr, Ba, Zn, Cr, Sn, or Pb, etc., and Q is at least one selected from Cl, Br, or I, etc. Further, E is, for example, Mg, Q is, for example, Cl, and the value range of g is, for example, 0.01 ≦ g ≦ 0.1, and specifically, g is, for example, 0.02. By controlling the type of E element, the type of Q element, and the value range of g in the first electrolyte, the cycle performance of the all-solid-state battery 10 can be enhanced, thereby extending the service life of the battery.

[0027] Referring to Figure 1, in one embodiment of the present invention, when preparing the first solid electrolyte layer 131, first, under an inert gas atmosphere such as argon, the chemical formula of the first electrolyte Li a P 1-b M b S c O d X e or Li f P 1-g E g S w O g Q z Based on this, a Li source, P source, M source, S source, and X source, or a Li source, P source, E source, S source, and Q source are uniformly mixed according to their chemical ratios, and then, for example, placed in a ball mill and subjected to ball milling to obtain a precursor powder. Then, the precursor powder is subjected to high-temperature annealing and sintering to obtain a first electrolyte. The Li source is at least one selected from, for example, Li2S, LiCl, LiBr, or LiI, the P source is, for example, P2S5, the M source is, for example, an oxide of M, the S source is at least one from, for example, a Li source or a P source, the X source is, for example, derived from a Li source, the E source is, for example, an oxide of E, and the Q source is, for example, derived from a Li source. The ball material ratio is (1~100):1. The ball milling time is, for example, 1h~48h, and the rotation speed is, for example, 50rpm~1500rpm. The sintering temperature is, for example, 400°C to 600°C, and the sintering time is, for example, 1h to 48h. After obtaining the first electrolyte, the first solid electrolyte layer 131 is prepared by, for example, powder extrusion molding, wet coating, electrostatic coating, etc.

[0028] Referring to Figure 2, in one embodiment of the present invention, when the first solid electrolyte layer 131 is prepared by powder extrusion molding, first, the first electrolyte and the first binder are uniformly mixed, for example by low-temperature shearing, and then rapidly heated to perform high-temperature shearing to obtain a mixed material. Next, the mixed material is placed in a roller press and subjected to high-temperature roll pressing to obtain the first solid electrolyte layer 131. The first binder is at least one selected from, for example, PTFE, ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene copolymer (FEP), perfluoroalkoxy (PFA), polychlorotrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer, or polyvinylidene fluoride-chlorotrifluoroethylene copolymer. The content of the first electrolyte in the mixed material is, for example, 95 wt% to 99.9 wt%. The content of the first binder in the mixed material is, for example, 0.1 wt% to 5 wt%. The low-temperature shear temperature is, for example, -30°C to 15°C, and the high-temperature shear temperature is, for example, 20°C to 200°C. The high-temperature roll press temperature is, for example, 20°C to 200°C.

[0029] Referring to Figure 1, in another embodiment of the present invention, when the first solid electrolyte layer 131 is prepared by wet coating or electrostatic coating, first, the first electrolyte, the second binder, and the solvent are uniformly mixed to obtain a mixed component. Then, the mixed component is applied to the substrate by wet coating or electrostatic coating. Next, the substrate coated with the mixed component is dried at a high temperature to obtain the first solid electrolyte layer 131. The second binder is at least one selected from, for example, PVDF, carboxymethylcellulose (CMC), polymerized styrene-butadiene rubber (SBR), polyvinylpyrrolidone (PVP), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyacrylic acid (PAA), polyurethane, polyvinyl alcohol (PVA), sodium alginate (Alg), ethylene-propylene-diene monomer, styrene-butadiene rubber, polyvinylidene fluoride, fluororubber, β-cyclodextrin polymer (β-CDp), polypropylene emulsion (LA132), PTFE, ETFE, FEP, PFA, PCTFE, ECTFE, polyvinylidene fluoride-hexafluoropropene copolymer, or vinylidene fluoride-chlorotrifluoroethylene copolymer. The solvent is at least one selected from, for example, toluene, chlorobenzene, xylene, dimethyl carbonate, N-methylformamide, n-hexane, diethylene glycol dimethyl ether, dibutyl ether, ethanol, 1,2-ethylenediamine, 1,2-ethanedithiol, acetonitrile, tetrahydrofuran, methanol, diisopropyl ether, acetone, hexene, ethyl acetate, benzyl acetate, butyl butyrate, or diisobutyl ketone. The content of the first electrolyte in the mixed component is, for example, 30 wt% to 90 wt%. The content of the second binder in the mixed component is, for example, 0.1 wt% to 10 wt%. The content of the solvent in the mixed component is, for example, 10 wt% to 50 wt%. The substrate is selected from, for example, polyethylene glycol terephthalate (PET) film, smooth aluminum foil, or release paper. The high-temperature drying temperature is, for example, 30°C to 250°C.

[0030] Referring to Figure 1, in one embodiment of the present invention, the second solid electrolyte layer 132 includes a first electrolyte and a second electrolyte. The first electrolyte is the same as the first electrolyte in the first solid electrolyte layer 131 described above and will not be repeated here. The second electrolyte is, for example, a lithium reduction reaction type sulfide electrolyte, which consumes the generated lithium dendrites, prevents the penetration of lithium dendrites, avoids short circuits in the all-solid-state battery 10, and can ensure that the all-solid-state battery 10 can still operate stably and safely even at high rates. Specifically, in the second solid electrolyte layer 132, the content of the first electrolyte is, for example, 1 wt% to 95 wt%, and the content of the second electrolyte is, for example, 5 wt% to 99 wt%. The chemical formula of the second electrolyte is, for example, Li 10 Ge 1-i G i P2S 12 Here, 0 ≤ i < 1, and G is at least one selected from Si or Sn, etc. Specifically, in this embodiment, i is, for example, 0. By controlling the value of i, the cycle performance of the all-solid-state battery 10 can be improved, thereby extending the battery's lifespan.

[0031] Referring to Figures 1 and 2, in one embodiment of the present invention, when preparing the second solid electrolyte layer 132, first, under an inert gas atmosphere such as argon, the chemical formula of the second electrolyte Li 10 Ge 1-i G i P2S 12Based on this, Li source, Ge source, G source, P source, and S source are mixed uniformly according to their chemical ratios, and then, for example, placed in a ball mill and subjected to ball milling to obtain a second electrolyte precursor powder. Then, the second electrolyte precursor is subjected to high-temperature annealing and sintering to obtain the second electrolyte. In this mixture, the Li source is, for example, Li2S, the Ge source is, for example, GeS2, the G source is, for example, a sulfide of G, the P source is, for example, P2S5, and the S source is derived from at least one of the Li source, Ge source, G source, or P source, etc. The ball material ratio is (1~100):1. The ball milling time is, for example, 1h~48h, and the rotation speed is, for example, 50rpm~1000rpm. The sintering temperature is, for example, 500℃~800℃, and the sintering time is, for example, 1h-48h. Next, the first electrolyte is prepared based on the chemical formula of the first electrolyte. The preparation process for the first electrolyte is the same as the preparation process for the first electrolyte in the first solid electrolyte layer 131, and will not be described repeatedly here. After obtaining the first and second electrolytes, the first and second electrolytes are mixed uniformly to obtain a mixed electrolyte material. Then, the second solid electrolyte layer 132 is prepared by, for example, powder extrusion molding, wet coating, or electrostatic coating. Of these, the process for preparing the second solid electrolyte layer 132 by powder extrusion molding, wet coating, or electrostatic coating is the same as the process for preparing the first solid electrolyte layer 131 by powder extrusion molding, wet coating, or electrostatic coating, and will not be described repeatedly here.

[0032] Referring to Figure 1, in one embodiment of the present invention, when preparing the solid electrolyte membrane 13, the first solid electrolyte layer 131, the second solid electrolyte layer 132, and the first solid electrolyte layer 131 described above are roll-pressed in order to compound them as a solid electrolyte membrane 13.

[0033] Referring to Figure 1, in one embodiment of the present invention, the positive electrode 11, solid electrolyte membrane 13, and negative electrode 12 described above are assembled by sequentially performing processes such as stacking, packaging, hot pressing, and cold pressing to construct the all-solid-state battery 10.

[0034] The present invention will be described more specifically below by citing examples. These examples should not be construed as limiting the present invention. Appropriate modifications can be made without departing from the spirit of the present invention, and all of them belong to the technical scope of the present invention. [Examples]

[0035] Example 1 Preparation of the first electrolyte: Under an argon atmosphere, 2 mol of Li2S, 1.5 mol of LiCl, 0.48 mol of P2S5, and 0.02 mol of Sb2O5 were subjected to high-energy ball milling to obtain a precursor powder. After that, the precursor powder was sintered at a temperature of 500 °C for 10 h, and after cooling, a Li 5.5 P 0.96 Sb 0.04 S 4.40 O 0.10 Cl 1.5 electrolyte material was obtained. (

[0036] <00004​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​1.5 A mixed component of PTFE was obtained. Then, Li 5.5 P 0.96 S 0.04 S 4.40 O 0.10 Cl 1.5 The PTFE mixture was pressed into a roll press machine, and the electrolyte membrane was roll-pressed to a thickness of 15 μm at 80°C by adjusting the gap of the roll press machine, thereby preparing the first solid electrolyte layer.

[0038] Preparation of the second solid electrolyte layer: 5 wt% Li 10 GeP2S 12 Electrolyte material and 95 wt% Li 5.5 P 0.96 S 0.04 S 4.40 O 0.10 Cl 1.5 The electrolyte materials were uniformly mixed to obtain a mixed electrolyte material. Next, the mixed electrolyte material and PTFE were uniformly mixed at -20°C according to a mass ratio of 99:1, and the temperature was raised to 80°C to fibrousize the PTFE, thereby obtaining a mixed component for preparing the second solid electrolyte layer. The mixed component was then pressed into a roll press machine, and the electrolyte membrane was roll-pressed to a thickness of 5 μm at 80°C by adjusting the gap of the roll press machine, thereby preparing the second solid electrolyte layer.

[0039] Preparation of the solid electrolyte membrane: The first solid electrolyte layer, the second solid electrolyte layer, and the first solid electrolyte layer were sequentially roll-pressed in a roll press machine to form a composite solid electrolyte membrane.

[0040] Cathode preparation: LiNi 0.8 Co 0.1 Mn 0.1 O2 cathode active material, Li 2.35 Zr 0.65 Fe 0.35 Cl5Br 0.5 I 0.5 A halogen solid electrolyte, a conductive agent, and PTFE were uniformly mixed according to a mass ratio of, for example, 69:29:1:1, and then a positive electrode was obtained by dry pressing. The conductive agent contained Super P and VGCF, and the mass ratio of Super P to VGCF was, for example, 1:1.

[0041] Negative electrode selection: Lithium metal was selected as the negative electrode.

[0042] Battery fabrication: The positive electrode, solid electrolyte membrane, and negative electrode were assembled into an all-solid-state soft pack battery by sequentially performing processes such as lamination, packaging, hot pressing, and cold pressing.

[0043] Example 2 The difference between this embodiment and Example 1 is that the content of the first electrolyte and the second electrolyte in the second solid electrolyte layer is 50 wt%, while everything else is the same as in Example 1.

[0044] Example 3 The difference between this example and Example 1 is that in the second solid electrolyte layer, the content of the first electrolyte is 20 wt%, and the content of the second electrolyte is 80 wt%.

[0045] Example 4 The difference between this example and Example 1 is that in the second solid electrolyte layer, the content of the first electrolyte is 1 wt%, and the content of the second electrolyte is 99 wt%.

[0046] Example 5 The difference between this example and Example 3 is that the chemical formula of the second electrolyte is Li 10 Ge 0.5 Sn 0.5 P2S 12 The key difference is that the raw materials are 1 mol of Li2S, 1 mol of P2S5, 0.5 mol of GeS2, and 0.5 mol of SnS2.

[0047] Example 6 The difference between this example and Example 3 is that the chemical formula of the second electrolyte is Li 10 Ge 0.5 Si 0.5 P2S 12 The key difference is that the raw materials are 1 mol of Li2S, 1 mol of P2S5, 0.5 mol of GeS2, and 0.5 mol of SiS2.

[0048] Example 7 The difference between this embodiment and Embodiment 3 is that the thickness of the second solid electrolyte layer was adjusted to 1 μm by adjusting the gap of the roll press machine.

[0049] Example 8 The difference between this embodiment and Embodiment 3 is that the thickness of the second solid electrolyte layer was adjusted to 50 μm by adjusting the gap of the roll press machine.

[0050] Example 9 The difference between this embodiment and Embodiment 3 is that the thickness of the second solid electrolyte layer was adjusted to 100 μm by adjusting the gap of the roll press machine.

[0051] Example 10 The difference between this embodiment and Embodiment 3 is that the thickness of the first solid electrolyte layer was adjusted to 1 μm by adjusting the gap of the roll press machine.

[0052] Example 11 The difference between this embodiment and Embodiment 3 is that the thickness of the first solid electrolyte layer was adjusted to 50 μm by adjusting the gap of the roll press machine.

[0053] Example 12 The difference between this embodiment and Embodiment 3 is that the thickness of the first solid electrolyte layer was adjusted to 120 μm by adjusting the gap of the roll press machine.

[0054] Example 13 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li 5.5 P 0.99 S 0.01 S 4.475 O 0.025 Cl 1.5 The key difference is that the raw materials are 2 mol of Li2S, 1.5 mol of LiCl, 0.495 mol of P2S5, and 0.05 mol of Sb2O5.

[0055] Example 14 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li5.5 P 0.9 S 0.1 S 4.25 O 0.25 Cl 1.5 The key difference is that the raw materials are 2 mol of Li2S, 1.5 mol of LiCl, 0.45 mol of P2S5, and 0.05 mol of Sb2O5.

[0056] Example 15 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li 5.5 P 0.96 S 0.04 S 4.40 O 0.10 Cl 1.3 Br 0.1 I 0.1 The key difference is that the raw materials are 2 mol of Li2S, 1.3 mol of LiCl, 0.1 mol of LiBr, 0.1 mol of LiI, 0.48 mol of P2S5, and 0.02 mol of Sb2O5.

[0057] Example 16 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li 5.52 P 0.99 Bi 0.01 S 4.485 O 0.015 Cl 1.5 The key difference is that the raw materials are 2.01 mol of Li2S, 1.5 mol of LiCl, 0.495 mol of P2S5, and 0.005 mol of Bi2O3.

[0058] Example 17 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li 5.54 P 0.98 Bi 0.02 S 4.47 O 0.03 Cl 1.5 The key difference is that the raw materials are 2.02 mol of Li2S, 1.5 mol of LiCl, 0.49 mol of P2S5, and 0.01 mol of Bi2O3.

[0059] Example 18 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li5.7 P 0.9 Bi 0.1 S 4.35 O 0.15 Cl 1.5 The key difference is that the raw materials are 2.1 mol of Li2S, 1.5 mol of LiCl, 0.45 mol of P2S5, and 0.05 mol of Bi2O3.

[0060] Example 19 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li 5.54 P 0.98 Bi 0.02 S 4.47 O 0.03 Cl 1.3 Br 0.1 I 0.1 The key difference is that the raw materials are 2.02 mol of Li2S, 1.3 mol of LiCl, 0.1 mol of LiBr, 0.1 mol of LiI, 0.49 mol of P2S5, and 0.01 mol of Bi2O3.

[0061] Example 20 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li 5.52 P 0.99 In 0.01 S 4.485 O 0.015 Cl 1.5 The key difference is that the raw materials are 2.01 mol of Li2S, 1.5 mol of LiCl, 0.495 mol of P2S5, and 0.005 mol of In2O3.

[0062] Example 21 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li 5.54 P 0.98 In 0.02 S 4.47 O 0.03 Cl 1.5 The key difference is that the raw materials are 2.02 mol of Li2S, 1.5 mol of LiCl, 0.49 mol of P2S5, and 0.01 mol of In2O3.

[0063] Example 22 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li5.7 P 0.9 In 0.1 S 4.35 O 0.15 Cl 1.5 The key difference is that the raw materials are 2.1 mol of Li2S, 1.5 mol of LiCl, 0.45 mol of P2S5, and 0.05 mol of In2O3.

[0064] Example 23 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li 5.54 P 0.98 In 0.02 S 4.47 O 0.03 Cl 1.3 Br 0.1 I 0.1 The key difference is that the raw materials are 2.02 mol of Li2S, 1.3 mol of LiCl, 0.1 mol of LiBr, 0.1 mol of LiI, 0.49 mol of P2S5, and 0.01 mol of In2O3.

[0065] Example 24 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li 5.53 P 0.99 Mg 0.01 S 4.49 O 0.01 Cl 1.5 The key difference is that the raw materials are 2.015 mol of Li2S, 1.5 mol of LiCl, 0.495 mol of P2S5, and 0.01 mol of MgO.

[0066] Example 25 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li 5.56 P 0.98 Mg 0.02 S 4.48 O 0.02 Cl 1.5 The key difference is that the raw materials are 2.03 mol of Li2S, 1.5 mol of LiCl, 0.49 mol of P2S5, and 0.02 mol of MgO.

[0067] Example 26 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li5.8 P 0.9 Mg 0.1 S 4.48 O 0.1 Cl 1.5 The key difference is that the raw materials are 2.15 mol of Li2S, 1.5 mol of LiCl, 0.45 mol of P2S5, and 0.1 mol of MgO.

[0068] Example 27 The difference between this example and Example 3 is that the chemical formula of the first electrolyte is Li 5.56 P 0.98 Mg 0.02 S 4.48 O 0.02 Cl 1.3 Br 0.1 I 0.1 The key difference is that the raw materials are 2.03 mol of Li2S, 1.3 mol of LiCl, 0.1 mol of LiBr, 0.1 mol of LiI, 0.49 mol of P2S5, and 0.02 mol of MgO.

[0069] Example 28 The difference between this embodiment and Embodiment 3 lies in the fact that ETFE was selected and used as the first binder in the preparation process of the first and second solid electrolyte layers.

[0070] Example 29 The difference between this embodiment and Embodiment 3 lies in the fact that PCTFE was selected and used as the first binder in the preparation process of the first and second solid electrolyte layers.

[0071] Example 30 The difference between this embodiment and Embodiment 3 lies in the fact that the first solid electrolyte layer and the second solid electrolyte layer were prepared using a wet coating method.

[0072] Specifically, preparation of the first solid electrolyte layer in this embodiment: Li 5.5 P 0.96 S 0.04 S 4.40 O 0.10 Cl 1.5The electrolyte material, SBR binder, and xylene solvent were uniformly mixed according to a mass ratio of 49:1:50 to obtain a mixed component. The mixed component was coated onto smooth aluminum foil using a 15 μm coating machine and vacuum-dried at 80°C to obtain a 15 μm thick Li 5.5 P 0.96 S 0.04 S 4.40 O 0.10 Cl 1.5 The first solid electrolyte layer was fabricated.

[0073] Preparation of the second solid electrolyte layer: 5 wt% Li 10 GeP2S 12 Electrolyte material and 95 wt% Li 5.5 P 0.96 S 0.04 S 4.40 O 0.10 Cl 1.5 The electrolyte materials were uniformly mixed to obtain a mixed electrolyte material. Next, the mixed electrolyte material, SBR binder, and xylene solvent were uniformly mixed according to a mass ratio of 49:1:50 to obtain a mixed component. The mixed component was coated onto a smooth aluminum foil using a 5 μm coating machine and vacuum-dried at 80°C to produce a 5 μm thick second solid electrolyte layer.

[0074] Example 31 The difference between this embodiment and Example 30 is that PVDF was selected and used as the second binder in the preparation process of the first and second solid electrolyte layers; otherwise, it is the same as Example 30.

[0075] Example 32 The difference between this embodiment and Example 30 is that PAA was selected and used as the second binder in the preparation process of the first and second solid electrolyte layers; otherwise, it is the same as Example 30.

[0076] Comparative Example 1 The difference between this comparative example and Example 3 is that the chemical formula of the first electrolyte is Li 5.5 PS 4.5 Cl 1.5The key difference lies in the fact that the raw materials are 2 mol of Li2S, 1.5 mol of LiCl, and 0.5 mol of P2S5.

[0077] Comparative Example 2 The difference between this comparative example and Example 3 is that the solid electrolyte membrane in this comparative example includes only the first solid electrolyte layer, which is formed by stacking two layers.

[0078] Comparative Example 3 The difference between this comparative example and Example 3 is that the solid electrolyte membrane in this example contains only the second solid electrolyte layer.

[0079] Table 1 shows the composition and parameters of the first and second solid electrolyte layers in each example and comparative example.

[0080] [Table 1] Composition table of the first solid electrolyte layer and the combined second solid electrolyte layer in Examples 1-32 and Comparative Examples 1-3 [Table 1] JPEG0007888837000002.jpg224160JPEG0007888837000003.jpg224160JPEG0007888837000004.jpg224160JPEG0007888837000005.jpg240160

[0081] In the present invention, performance tests were conducted on all-solid-state batteries prepared using different solid electrolyte membranes in Examples 1 to 32 and Comparative Examples 1 to 3.

[0082] Referring to Figure 3, in one embodiment of the present invention, the morphology of the solid electrolyte membrane in Example 3 was characterized, for example, by a scanning electron microscope. The magnification of the scanning electron microscope was, for example, 5000x. As can be seen from Figure 3, the first solid electrolyte layer and the second solid electrolyte layer prepared by powder extrusion molding have good self-supporting properties and are stably present between the positive electrode and the negative electrode, thereby allowing the solid electrolyte membrane to exhibit more favorable performance.

[0083] Referring to Figure 4, in one embodiment of the present invention, for example, a room-temperature cycle performance test was performed on the all-solid-state battery of Example 3. Specifically, at 25°C, with a charge / discharge rate of 1C / 1C, the all-solid-state battery was subjected to cycle charging and discharging within the specified voltage range of 2.5V to 4.3V, and the capacity (CC) and Coulomb efficiency (CE) at different cycle counts were obtained. As can be seen from Figure 4, the tendency of the battery capacity to decay with increasing cycle count is relatively gradual, and the Coulomb efficiency of the battery does not fluctuate and remains stable around 100%, indicating that the battery has good cycle performance.

[0084] Referring to Figure 2, in one embodiment of the present invention, a room-temperature cycle stability test was performed on the all-solid-state batteries in Examples 1 to 32 and Comparative Examples 1 to 3. Specifically, at 25°C, with a charge / discharge rate of 1C / 1C, the all-solid-state batteries were cycle-charged and discharged within the specified voltage range of 2.5V to 4.3V. The test was terminated when the battery capacity reached the cycle start capacity of 80% State of Health (SOH), and the number of room-temperature cycles of the battery was recorded. The recorded results are shown in Table 2.

[0085] [Table 2] Test results of all-solid-state batteries in Examples 1-32 and Comparative Examples 1-3 [Table 2] JPEG0007888837000007.jpg61160

[0086] Referring to Tables 1 and 2, and comparing Example 3, Comparative Example 2, and Comparative Example 3, it can be seen that when the two-layer first solid electrolyte membrane is used alone, the number of room-temperature cycles of the battery is 553, and when the second solid electrolyte membrane is used alone, the number of room-temperature cycles of the battery is only 29. However, when the first solid electrolyte membrane, the second solid electrolyte membrane, and the first solid electrolyte membrane are combined in sequence to form a solid electrolyte membrane, the number of room-temperature cycles of the battery increases to 1146. This indicates that in the solid electrolyte membrane, the first electrolyte in the first solid electrolyte layer enhances the interfacial stability between the solid electrolyte membrane and the negative electrode, ensuring a continuous and stable lithium ion transmission channel, while the second electrolyte in the second solid electrolyte layer consumes lithium dendrites, prevents lithium dendrite penetration, avoids short circuits in the all-solid-state battery, and thereby improves the battery's cycle performance.

[0087] As can be seen by referring to Tables 1 and 2 and comparing Examples 1 to 4, the second electrolyte Li in the second solid electrolyte layer 10 GeP2S 12 As the ratio of increases, the ionic conductivity of the second solid electrolyte layer gradually increases, and the number of room-temperature cycles of the battery first gradually increases, and then gradually decreases. In other words, the battery's cycle performance tends to increase first and then decrease. Therefore, the battery's cycle performance can be improved by controlling the content of the second electrolyte in the second solid electrolyte layer.

[0088] As can be seen by referring to Table 1 and Table 2 and comparing Examples 3, 5, and 6, there are three types of second electrolyte Li 10 GeP2S 12 Li 10 Ge 0.5 Sn 0.5 P2S 12 , and Li 10 Ge 0.5 Si 0.5 P2S 12 Of these, Li 10 GeP2S 12 The battery assembled with Li as the second electrolyte has the highest number of cycles at room temperature. 10 Ge 1-i G i P2S12 In this case, if i is 0, it indicates that the battery's cycle performance is optimal. Therefore, the battery's cycle performance can be improved by controlling the mixing ratio of Ge and G elements in the second electrolyte.

[0089] Referring to Tables 1 and 2, and comparing Example 3 with Examples 7-9, it can be seen that as the thickness of the second solid electrolyte layer increases from 1 μm to 100 μm, the number of room-temperature cycles of the battery first gradually increases and then gradually decreases. In other words, the battery's cycle performance tends to increase first and then decrease. Referring to Tables 1 and 2, and comparing Example 3 with Examples 10-12, it can be seen that as the thickness of the first solid electrolyte layer increases from 1 μm to 120 μm, the number of room-temperature cycles of the battery first gradually increases and then gradually decreases. In other words, the battery's cycle performance tends to increase first and then decrease. Therefore, the battery's cycle performance can be improved by controlling the thickness of the first and second solid electrolyte layers.

[0090] As can be seen by referring to Tables 1 and 2 and comparing Examples 3, 13, and 14, as the amount of Sb element mixed in the first electrolyte increases, the ionic conductivity of the first and second solid electrolyte layers gradually decreases, and the number of room-temperature cycles of the battery gradually increases and then decreases. In other words, the battery's cycle performance tends to increase first and then decrease. As can be seen by referring to Tables 1 and 2 and comparing Examples 16 to 18, as the amount of Bi element mixed in the first electrolyte increases, the ionic conductivity of the first and second solid electrolyte layers gradually decreases, and the number of room-temperature cycles of the battery gradually increases and then decreases. In other words, the battery's cycle performance tends to increase first and then decrease. As can be seen by referring to Tables 1 and 2 and comparing Examples 20 to 22, as the amount of In element mixed in the first electrolyte increases, the ionic conductivity of the first and second solid electrolyte layers gradually decreases, and the number of room-temperature cycles of the battery gradually increases and then decreases. In other words, the battery's cycle performance tends to increase first, and then decrease. Therefore, the battery's cycle performance can be improved by controlling the amount of M element mixed in the first electrolyte.

[0091] As can be seen by referring to Tables 1 and 2 and comparing Examples 24-26, the ionic conductivity gradually decreases with increasing amounts of Mg in the first electrolyte, and the number of room-temperature cycles of the battery gradually increases and then decreases. In other words, the battery's cycle performance tends to increase first and then decrease. Therefore, the battery's cycle performance can be improved by controlling the amount of E in the first electrolyte.

[0092] As can be seen by referring to Tables 1 and 2 and comparing Examples 3 and 15, Examples 17 and 19, Examples 21 and 23, and Examples 25 and 27, when the mixing amounts of Sb, In, Bi, or Mg elements in the first electrolyte are the same, mixing Br and I elements into the first electrolyte reduces the ionic conductivity of the first and second solid electrolyte layers, and also reduces the number of room-temperature cycles of the battery. In other words, the battery's cycle performance deteriorates. Therefore, the battery's cycle performance can be improved by controlling the number of element types containing X or Q in the first electrolyte.

[0093] Referring to Tables 1 and 2, and comparing Examples 3, 17, 21, 25, and Comparative Example 1, it can be seen that when Sb, Bi, In, or Mg elements are not mixed into the first electrolyte, the ionic conductivity of the first and second solid electrolyte layers changes significantly, but the number of room-temperature cycles of the battery is only 82, indicating that it has no cycle performance. This shows that the Sb, Bi, In, or Mg elements mixed in the first and second solid electrolyte layers significantly improve the cycle performance of the battery. Therefore, the cycle performance of the battery can be improved by controlling the type of M or E element in the first electrolyte.

[0094] As can be seen by referring to Tables 1 and 2 and comparing Examples 3, 28, and 29, the difference in the first binder used in the preparation process of the first and second solid electrolyte layers results in differences in the ionic conductivity of the first and second solid electrolyte layers, and thus differences in the battery's cycle performance. Specifically, when PTFE is used as the first binder, the ionic conductivity of the first and second solid electrolyte layers is maximized, and the number of room-temperature cycles of the battery is also the highest. In other words, the battery's cycle performance is most desirable.

[0095] As can be seen by referring to Tables 1 and 2 and comparing Examples 3 and 30-32, the difference in the preparation methods of the first and second solid electrolyte layers results in differences in their ionic conductivity and thus differences in the battery's cycle performance. Specifically, the first and second solid electrolyte layers prepared by powder extrusion molding have the highest ionic conductivity and the highest number of room-temperature cycles for the assembled battery, compared to wet coating. In other words, the cycle performance is most preferable.

[0096] The present invention further provides electronic devices. The electronic device includes at least one of the all-solid-state batteries described above. The all-solid-state battery is used to provide electrical energy. The electronic device may include vehicles, mobile phones, portable devices, notebook computers, ships, aircraft, electric toys, and power tools, etc. In one embodiment of the present invention, the vehicle is, for example, a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, etc. Aircraft include airplanes, rockets, space shuttles, spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, electric planers, etc. The electronic device includes the all-solid-state battery described above, and therefore includes the advantages of the all-solid-state battery described above, which will not be repeated here. [Industrial applicability]

[0097] In summary, the present invention provides an all-solid-state battery and its applications. By combining a first solid electrolyte layer, a second solid electrolyte layer, and a first solid electrolyte layer, a symmetrical, self-supporting solid electrolyte membrane can be fabricated, increasing the interfacial stability between the solid electrolyte membrane and the negative electrode, thereby reducing interfacial impedance and improving charge transfer efficiency. At the same time, the resistance of the solid electrolyte membrane to lithium dendrite penetration can be improved, preventing short circuits in the battery and ensuring that the battery can operate stably and safely at high rates. Simultaneously, the ionic conductivity of the solid electrolyte membrane can be increased, thereby improving the operating efficiency of the battery. Furthermore, the battery's cycle performance can be enhanced, extending its service life.

[0098] The above description merely describes preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the scope of the invention is not limited to technical solutions formed by specific combinations of the above technical features. At the same time, the present invention also covers other technical solutions formed by any combination of the above technical features or equivalent features, for example, technical solutions formed by replacing the above features with technical features (but not limited to) having similar functions as disclosed by the present invention, without departing from the concept of the present invention.

[0099] Except for the technical features described herein, the remaining technical features are well known to those skilled in the art. To emphasize the innovative features of the present invention, the remaining technical features are not described in detail here. [Explanation of Symbols]

[0100] 10: All-solid-state battery 11: Positive electrode 12: Negative electrode 13: Solid electrolyte membrane 131:First solid electrolyte layer 132:Second solid electrolyte layer

Claims

1. All-solid-state battery, The positive and negative electrodes of the aforementioned all-solid-state battery are provided, respectively, with an ionic conductivity of 1 × 10⁻⁶ －３ S / cm ~ 1 x 10 －２ A first solid electrolyte layer comprising at least two layers having a density of S / cm, It is provided between the two layers of the first solid electrolyte layer, and has an ionic conductivity of 1 × 10 －３ S / cm ~ 2 x 10 －２ The second solid electrolyte layer is S / cm and Includes at least Characterized by, All-solid-state battery.

2. The first solid electrolyte layer contains a first electrolyte, and the chemical formula of the first electrolyte is Li ａ P １－ｂ M ｂ S ｃ O ｄ X ｅ where 5 < a < 6, 0 < b < 1, 1.5 < c < 5, 0 < d < 2.5, 4 < c + d < 5, 1 < e < 2, M is at least one selected from Al, Ga, In, Ti, Sc, As, Sb, Bi, As, V, or Nb, and X is at least one selected from Cl, Br, or I Characterized by, The all-solid-state battery according to claim 1.

3. M is at least one selected from Sb, In, or Bi, X is Cl, and the range of b is 0 < b ≤ 0.

1. Characterized by, The all-solid-state battery according to claim 2.

4. The first solid electrolyte layer contains a first electrolyte, and the chemical formula of the first electrolyte is Li ｆ P １－ｇ E ｇ S ｗ O ｇ Q ｚ Here, 5 < f < 10, 0 < g < 1, 3 < w < 6, 4 < w + g < 6, 0 < z < 2, E is at least one selected from Mg, Ca, Sr, Ba, Zn, Cr, Sn, or Pb, and Q is at least one selected from Cl, Br, or I. Characterized by, The all-solid-state battery according to claim 1.

5. E is Mg, Q is Cl, and the range of g is 0.01 ≤ g ≤ 0.

1. Characterized by, The all-solid-state battery according to claim 4.

6. The second solid electrolyte layer comprises the first electrolyte and the second electrolyte, and the chemical formula of the second electrolyte is Li １０ Ge １－ｉ G ｉ P ２ S １２ Here, 0 ≤ i < 1 and G is at least one selected from Si or Sn. Characterized by, All-solid-state battery according to any one of claims 2 to 5.

7. In the second solid electrolyte layer, the content of the first electrolyte is 1 wt% to 95 wt%, and the content of the second electrolyte is 5 wt% to 99 wt%. Characterized by, The all-solid-state battery according to claim 6.

8. The thickness of the first solid electrolyte layer is 1 μm to 120 μm. Characterized by, The all-solid-state battery according to claim 1.

9. The thickness of the second solid electrolyte layer is 1 μm to 100 μm. Characterized by, The all-solid-state battery according to claim 1.

10. Includes the all-solid-state battery described in claim 1 Characterized by, electronic equipment.

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