All-solid-state battery containing lithium precipitate

Abstract

The present invention relates to a lithium-containing precipitated all-solid-state battery. Specifically, the present invention relates to an all-solid-state battery comprising: a cathode current collector layer, a first layer disposed on the cathode current collector layer, and the first layer comprising at least one selected from the group consisting of a particulate carbon material, a fibrous carbon material, and a combination thereof; a second layer disposed between the first layer and the cathode current collector layer, and the second layer comprising a carbon material having a layered structure; an electrolyte layer disposed on the first layer; and a composite anode layer disposed on the electrolyte layer.

Description

Technical Field

[0001] This disclosure relates to all-solid-state batteries having an anode-free structure containing lithium deposits. Background Technology

[0002] The all-solid-state battery includes a three-layer laminate comprising an anode composite layer bonded to an anode current collector (current collector), a cathode composite layer bonded to a cathode current collector, and a solid electrolyte disposed between the anode composite layer and the cathode composite layer.

[0003] Typically, the cathode composite layer of an all-solid-state battery is formed by mixing active materials and a solid electrolyte to ensure ionic conductivity. Because solid electrolytes have a higher specific gravity than liquid electrolytes, the energy density of conventional all-solid-state batteries, as described above, is lower than that of lithium-ion batteries.

[0004] To improve the energy density of all-solid-state batteries, research has been conducted targeting the use of lithium metal as the cathode. However, challenges remain, such as interface bonding, dendrite growth, cost, and the difficulty in achieving large-area applications.

[0005] Recently, a storage-anode-less type of battery has also been studied, in which the cathode of the all-solid-state battery is removed and lithium is directly deposited onto the cathode current collector. However, the problem with the above-mentioned battery is that due to the uneven deposition of lithium, the degree of irreversible reaction gradually increases, resulting in very poor durability.

[0006] The information included in this Background section is intended only to enhance the understanding of the general background of this disclosure and is not to be construed as an admission of prior art known to those skilled in the art or any form of implication. Summary of the Invention

[0007] The purpose of this disclosure is to provide an all-solid-state battery with a novel structure, characterized by improved durability compared to conventional anode-free all-solid-state batteries.

[0008] Another objective of this disclosure is to provide an all-solid-state battery with good durability and high energy density.

[0009] The purpose of this disclosure is not limited to the foregoing objectives. The objectives of this disclosure will become more apparent from the following description, and will be achieved by the means described in the claims and combinations thereof.

[0010] An all-solid-state battery according to an embodiment of the present disclosure includes: a cathode current collector layer; a first layer disposed on the cathode current collector layer, the first layer comprising at least one selected from particulate carbon material, fibrous carbon material, and combinations thereof; a second layer disposed between the first layer and the cathode current collector layer, the second layer comprising a carbon material having a layered structure; an electrolyte layer disposed on the first layer; and a composite anode layer disposed on the electrolyte layer.

[0011] The first layer can be porous.

[0012] Particulate carbon materials may include at least one selected from carbon black, graphitized carbon, non-graphitized carbon, and combinations thereof.

[0013] Particulate carbon materials can have a particle size (D50) of 0.01 to 5 μm.

[0014] Fibrous carbon materials may include at least one selected from carbon nanofibers, carbon nanotubes, vapor-grown carbon fibers, and combinations thereof.

[0015] Carbon fiber materials can have diameters ranging from 0.01 to 5 μm.

[0016] The first layer can have a thickness of 3 to 30 μm.

[0017] The first layer may further include powdered metal capable of forming alloys with lithium.

[0018] The metal may include at least one selected from aluminum (Al), zinc (Zn), indium (In), silver (Ag), gold (Au), magnesium (Mg), silicon (Si), bismuth (Bi), germanium (Ge), platinum (Pt), antimony (Sb), and combinations thereof.

[0019] Metals can have a particle size of 0.01 to 5 μm (D50).

[0020] Carbon materials with a layered structure may include at least one selected from graphite, graphene with a layered structure, and combinations thereof.

[0021] In all-solid-state batteries, lithium deposits can be inserted between layers of carbon material with a layered structure during charging.

[0022] In all-solid-state batteries, the second layer can be thinner than the first layer.

[0023] The second layer can have a thickness of 0.5 to 5 μm.

[0024] The all-solid-state battery may further include a lithium metal layer located between the second layer and the cathode current collector layer. The lithium metal layer may contain lithium deposits.

[0025] According to this disclosure, since lithium can be uniformly deposited on the cathode current collector layer, an all-solid-state battery with improved durability and energy density can be obtained.

[0026] The effects of this disclosure are not limited to those described above. It should be understood that the effects of this disclosure include all effects that can be inferred from the following description. Attached Figure Description

[0027] Figure 1 This is a cross-sectional view showing an all-solid-state battery according to one embodiment of the present disclosure;

[0028] Figure 2 This is a cross-sectional view showing the state of charge of an all-solid-state battery according to one embodiment of the present disclosure;

[0029] Figure 3 The results obtained by analyzing the cross-section of the all-solid-state battery manufactured in the example using a scanning electron microscope are shown.

[0030] Figure 4A The results are shown by analyzing a cross-section of the all-solid-state battery in the embodiment using a scanning electron microscope.

[0031] Figure 4B The results are shown by analyzing the cross-section of the all-solid-state battery in the comparative embodiment using a scanning electron microscope.

[0032] Figure 5A The results are shown by measuring the charge and discharge capacities of the solid-state batteries in the embodiments and comparative embodiments; and

[0033] Figure 5B The results are shown by measuring the capacity retention rate using the number of charge and discharge cycles of solid-state batteries according to the embodiments and comparative embodiments. Detailed Implementation

[0034] The above and other objects, features, and advantages of this disclosure will become clearer from the following preferred embodiments, taken in conjunction with the accompanying drawings. However, this disclosure is not limited to the embodiments disclosed herein and can be modified in various forms. These embodiments are provided to thoroughly explain this disclosure and to fully convey the spirit of this disclosure to those skilled in the art.

[0035] Throughout the accompanying drawings, the same reference numerals will refer to the same or similar elements. For clarity of this disclosure, the dimensions of the structures are depicted as larger than their actual dimensions. It will be understood that although terms such as “first,” “second,” etc., may be used herein to describe various elements, these elements are not limited by these terms. These terms are used only to distinguish one element from another. For example, an “first” element discussed below may be referred to as a “second” element without departing from the scope of this disclosure. Similarly, a “second” element may also be referred to as a “first” element. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise.

[0036] Furthermore, it is understood that the terms "comprising," "including," and "having," when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. Additionally, it should be understood that when an element such as a layer, film, region, or sheet is referred to as being "above" another element, it may be directly on the other element, or intermediate elements may exist between them. Similarly, when an element such as a layer, film, region, or sheet is referred to as being "below" another element, it may be directly below the other element, or intermediate elements may exist between them.

[0037] Unless otherwise stated, all figures, values, and / or representations indicating the amounts of components, reaction conditions, polymer compositions, and mixtures used herein are considered to include approximations of various uncertainties affecting the measured values, uncertainties that are inherently present at the time of obtaining these values, and should therefore be understood to be modified by the term "about" in all cases. Furthermore, when numerical ranges are disclosed in this specification, unless otherwise stated, the ranges are continuous and include all values ​​from the minimum to the maximum of the range. Additionally, when such ranges pertain to integer values, unless otherwise stated, they include all integers containing the minimum to the maximum value.

[0038] Figure 1 An all-solid-state battery according to an embodiment of the present disclosure is shown. The all-solid-state battery 1 includes a cathode current collector layer 10, a lithium absorber layer 20 located on the cathode current collector layer 10 and providing a lithium deposition space, an electrolyte layer 30 located on the lithium absorber layer 20, and a composite anode layer 40 located on the electrolyte layer 30.

[0039] The cathode current collector layer 10 can be a sheet-like substrate. Alternatively, the cathode current collector layer 10 can be a metal thin film comprising at least one metal selected from copper (Cu), nickel (Ni), and combinations thereof. Specifically, the cathode current collector layer 10 can be a high-density metal thin film having a porosity of less than about 1%.

[0040] The thickness of the cathode current collector layer 10 can be 1 to 20 μm, or more specifically 5 to 15 μm.

[0041] The lithium absorber layer 20 includes a first layer 21 and a second layer 22 located between the first layer 21 and the cathode current collector layer 10.

[0042] The first layer 21 can be a porous layer having amorphous pores. When the all-solid-state battery 1 is charged, lithium ions generated from the composite anode layer 40 and then moving through the electrolyte layer 30 can be deposited in the pores of the first layer 21.

[0043] When the all-solid-state battery 1 is charged, lithium ions generated from the composite anode layer 40 and then moving through the electrolyte layer 30 can be deposited in the pores of the first layer 21.

[0044] The first layer 21 may include at least one selected from particulate carbon materials, fibrous carbon materials, and combinations thereof.

[0045] Particulate carbon materials may include at least one selected from carbon black, graphitized carbon, non-graphitized carbon, and combinations thereof.

[0046] There are no particular limitations on carbon black, but examples may include at least one selected from Super P, Super C, acetylene black, Ketjen black, and combinations thereof.

[0047] Graphitized carbon and non-graphitized carbon are non-graphite-based carbons, and can be carbon materials in which crystallizing agents are entangled together and arranged in a disordered manner.

[0048] The particle size (D50) of the particulate carbon material, such as its diameter, can be from 0.01 to 5 μm. Sufficient porosity can only be formed in the first layer 21 when the particle size (D50) of the particulate carbon material falls within the aforementioned range. Here, the median value for the particle size distribution is referred to as D50 (or x50 when following certain ISO guidelines). D50 is a dimension in micrometers that separates the distribution above and below half the diameter.

[0049] The first layer 21, which contains fibrous carbon material, may have a network structure formed by connecting the fibrous carbon material in three dimensions.

[0050] The fibrous carbon material may include at least one selected from carbon nanofibers, carbon nanotubes, vapor-grown carbon fibers, and combinations thereof.

[0051] The diameter of the fibrous carbon material can be from 0.01 to 5 μm. Sufficient porosity can only be formed in the first layer 21 when the diameter of the fibrous carbon material falls within the above-mentioned range.

[0052] The first layer 21 may have a thickness of 3 to 30 μm. Furthermore, the porosity of the first layer 21 may be 10 to 80%. Only when the thickness and porosity of the first layer 21 fall within the aforementioned range can the energy density of the all-solid-state battery be improved.

[0053] The first layer 21 may further contain powdered metal capable of forming an alloy with lithium.

[0054] In the first layer 21, the metal can act as a seed for lithium ions. Specifically, as the all-solid-state battery 1 is charged, lithium ions mainly grow into lithium around the metal.

[0055] The metal may include at least one selected from aluminum (Al), zinc (Zn), indium (In), silver (Ag), gold (Au), magnesium (Mg), silicon (Si), bismuth (Bi), germanium (Ge), platinum (Pt), antimony (Sb), and combinations thereof.

[0056] There are no particular limitations on the particle size (D50) of the metal, but it can be, for example, 0.01 to 5 μm or 0.1 to 1 μm.

[0057] The second layer 22 may include a carbon material having a layered structure. The second layer 22 may be disposed in the form of a thin film between the first layer 21 and the cathode current collector 10. Because the first layer 21 has poor lithium-ion conductivity and contains amorphous pores, lithium ions move unevenly depending on their position within the first layer 21. Since the second layer 22 has a predetermined structure including a carbon material with a layered structure, it can act as a buffer layer for lithium ions to pass through the first layer 21. Specifically, lithium ions are uniformly stored between the layers of the carbon material with a layered structure in the second layer 22 and then begin to deposit on the lithium current collector layer 10. Therefore, according to this disclosure, due to the second layer 22, the rate of lithium ion movement and deposition, depending on its position, can be balanced, thereby causing uniform lithium deposition.

[0058] Carbon materials with a layered structure may include at least one selected from graphite, graphene with a layered structure, and combinations thereof.

[0059] Graphite refers to crystalline graphite, and can include both natural and artificial graphite.

[0060] Graphene with a laminated structure refers to graphene that has been laminated to form a layered structure.

[0061] The thickness of the second layer 22 can be 0.5 to 5 μm. This balances the migration and deposition rates of lithium ions, ensuring that lithium is uniformly deposited on the cathode current collector layer 10 only when the thickness of the second layer 22 falls within the aforementioned range.

[0062] Figure 2The state of charge of an all-solid-state battery 1 according to an embodiment of the present disclosure is shown. Referring to this, the all-solid-state battery 1 may further include a lithium metal layer A located between the second layer 22 and the cathode current collector layer 10. The lithium metal layer A includes a lithium deposit, and the lithium deposit may be a deposit of lithium ions passing through the first layer 21 and the second layer 22.

[0063] The electrolyte layer 30 is located between the porous layer 20 and the composite anode layer 40, thereby allowing lithium ions to move between the two components.

[0064] The electrolyte layer 30 may comprise an oxide-based solid electrolyte or a sulfide-based solid electrolyte. However, a sulfide-based solid electrolyte with high lithium-ion conductivity may be preferred. The sulfide-based solid electrolyte is not particularly limited, but may include Li₂S-P₂S₅, Li₂S-P₂S₅-LiI, Li₂S-P₂S₅-LiCl, Li₂S-P₂S₅-LiBr, Li₂S-P₂S₅-Li₂O, Li₂S-P₂S₅-Li₂O-LiI, Li₂S-SiS₂, Li₂S-SiS₂-LiI, Li₂S-SiS₂-LiBr, Li₂S-SiS₂-LiCl, Li₂S-SiS₂-B₂S₃-LiI, Li₂S-SiS₂-P₂S₅-LiI, Li₂S-B₂S₃, and Li₂S-P₂S₅-Z. m S n (where m and n are positive numbers, Z is one of Ge, Zn, and Ga, Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where x and y are positive numbers, and M is one of P, Si, Ge, B, Al, Ga, and In) or Li 10 GeP2S 12 .

[0065] The composite anode layer 40 may include an anode active material layer 41 disposed on the electrolyte layer 30 and an anode current collector layer 42 disposed on the anode active material layer 41.

[0066] The anodic active material layer 41 may include an anodic active material, a solid electrolyte, a conductive material, and a binder.

[0067] The anodic active material can be an oxide active material or a sulfide active material.

[0068] The oxide active material can be such as LiCoO2, LiMnO2, LiNiO2, LiVO2, and Li 1+x Ni 1 / 3 Co 1 / 3 Mn 1 / 3Rock-salt type active materials of O2, such as LiMn2O4 and Li(Ni 0.5 Mn 1.5 )O4, spinel type active materials such as LiNiVO4 and LiCoVO4, inverse spinel type active materials such as LiFePO4, LiMnPO4, LiCoPO4 and LiNiPO4, olivine type active materials such as Li2FeSiO4 and Li2MnSiO4, silicon-containing active materials such as LiNi 0.8 Co (0.2-x) Al x O2 (0 < x < 0.2), where a part of the transition metal is replaced by a foreign metal, spinel type active materials where a part of the transition metal is replaced by a foreign metal, such as Li 1+x Mn 2-x-y M y O4 (where M is at least one of Al, Mg, Co, Fe, Ni and Zn, and 0 < x + y < 2) or lithium titanate, such as Li4Ti5O 12 .

[0069] The sulfide active material can be copper chalcogenide, iron sulfide, cobalt sulfide or nickel sulfide.

[0070] The solid electrolyte can be an oxide solid electrolyte or a sulfide solid electrolyte. However, a sulfide-based solid electrolyte with high lithium ion conductivity can be used. The sulfide-based solid electrolyte is not particularly limited, but can be Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (where m and n are positive numbers, Z is one of Ge, Zn and Ga, Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where x and y are positive numbers, M is one of P, Si, Ge, B, Al, Ga and In) or Li 10 GeP2S 12 . The solid electrolyte can be the same as or different from the electrolyte included in the electrolyte layer 30.

[0071] The conductive material can be carbon black, conductive graphite, ethylene black, or graphene.

[0072] The binder can be BR (butadiene rubber), NBR (nitrile butadiene rubber), HNBR (hydrogenated nitrile butadiene rubber), PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), or CMC (carboxymethyl cellulose). The binder can be the same as or different from the binder contained in the porous layer 20.

[0073] The anode current collector layer 42 can be made of aluminum foil.

[0074] Other forms of this disclosure will now be described in more detail with reference to embodiments. These embodiments are merely illustrative of the present disclosure and are not intended to limit its scope.

[0075] Example

[0076] A first layer is formed, comprising Super C as particulate carbon material and silver (Ag) as metal. Silver (Ag) with a particle size (D50) of 0.15 μm is used. The thickness of the first layer is adjusted to 8 μm.

[0077] A thin film with a thickness of 1 μm is applied to the first layer using a wire spindle to form the second layer. Artificial graphite is used as the carbon material having the layered structure that constitutes the second layer.

[0078] The lithium absorber layer, comprising a first layer and a second layer, and the cathode current collector layer are used to... Figure 1 The configuration shown is combined, and an electrolyte layer and a composite anode layer are stacked on the lithium absorber layer to fabricate an all-solid-state battery. The cathode current collector layer, electrolyte layer, and composite anode layer are those commonly used in the art to which this disclosure pertains.

[0079] Figure 3 The results obtained by analyzing the cross-section of the all-solid-state battery according to the embodiment using a scanning electron microscope are shown.

[0080] Comparative Examples

[0081] The all-solid-state battery is manufactured in the same manner as in the above embodiments, except that a second layer is not formed. That is, in the all-solid-state battery of the comparative embodiment, a cathode current collector, a first layer, an electrolyte layer, an anode active material layer, and an anode current collector layer are stacked sequentially.

[0082] Experimental Example 1 – Scanning Electron Microscopy Analysis of an All-Solid-State Battery in Charge State

[0083] After the solid-state batteries according to the embodiments and comparative embodiments were charged, each all-solid-state battery was analyzed using a scanning electron microscope.

[0084] Figure 4AThe results of the embodiments are shown, and Figure 4B The results of the comparative embodiments are shown.

[0085] refer to Figure 4A As can be seen, in the all-solid-state battery according to the embodiment, even if the thickness of the lithium absorber layer 20 is not uniform, the deposited lithium metal layer A is uniform and dense.

[0086] refer to Figure 4B As can be seen, in the all-solid-state battery according to the comparative embodiment, the lithium metal layer A is not uniformly formed on the first layer, and many pores are formed. That is, in the all-solid-state battery of the comparative embodiment, a large amount of dead lithium is generated.

[0087] Experimental Example 2 – Battery Characteristic Evaluation

[0088] The charge and discharge capacities of the solid-state batteries according to the embodiments and comparative embodiments were measured. The results are shown in... Figure 5A middle.

[0089] In addition, the capacity retention rate of the solid-state batteries according to the embodiments and comparative embodiments was measured after a number of charge and discharge cycles. The results are shown in... Figure 5B middle.

[0090] refer to Figure 5A and 5B As can be seen, the all-solid-state battery in the embodiment has a larger capacity and also has a significantly improved capacity retention rate, i.e., durability.

[0091] This disclosure has been described in detail above with respect to the test embodiments and implementation schemes. However, the scope of this disclosure is not limited to the test embodiments and implementation schemes described above, and various modifications and improvements of this disclosure using the basic concepts of this disclosure as defined in the appended claims are also incorporated into the scope of this disclosure.

Claims

1. An all-solid-state battery, comprising: Cathode current collector layer; The first layer is disposed on the cathode current collector layer and comprises at least one selected from particulate carbon materials, fibrous carbon materials, and combinations thereof; The second layer is disposed between the first layer and the cathode current collector layer, and contains a carbon material with a layered structure. An electrolyte layer is disposed on the first layer; and A composite anode layer is disposed on the electrolyte layer. The first layer is porous. The porosity of the first layer is 10% to 80%, and The thickness of the first layer is 3 to 30 μm.

2. The all-solid-state battery according to claim 1, wherein the particulate carbon material comprises at least one selected from carbon black, graphitized carbon, non-graphitized carbon, and combinations thereof.

3. The all-solid-state battery according to claim 1, wherein the particulate carbon material has a particle size (D50) of 0.01 to 5 μm.

4. The all-solid-state battery according to claim 1, wherein the fibrous carbon material comprises at least one selected from carbon nanofibers, carbon nanotubes, vapor-grown carbon fibers, and combinations thereof.

5. The all-solid-state battery according to claim 1, wherein the diameter of the fibrous carbon material is 0.01 to 5 μm.

6. The all-solid-state battery of claim 1, wherein the first layer further comprises a powdered metal capable of forming an alloy with lithium.

7. The all-solid-state battery according to claim 6, wherein the metal comprises at least one selected from aluminum (Al), zinc (Zn), indium (In), silver (Ag), gold (Au), magnesium (Mg), silicon (Si), bismuth (Bi), germanium (Ge), platinum (Pt), antimony (Sb), and combinations thereof.

8. The all-solid-state battery of claim 6, wherein the metal has a particle size (D50) of 0.01 to 5 μm.

9. The all-solid-state battery according to claim 1, wherein the carbon material having the layered structure comprises at least one selected from graphite, graphene having a layered structure, and combinations thereof.

10. The all-solid-state battery of claim 1, wherein during charging, lithium deposits are configured to be disposed between the layers of the carbon material having a layered structure.

11. The all-solid-state battery according to claim 1, wherein the thickness of the second layer is less than the thickness of the first layer.

12. The all-solid-state battery of claim 1, wherein the thickness of the second layer is 0.5 to 5 μm.

13. The all-solid-state battery according to claim 1, further comprising a lithium metal layer disposed between the second layer and the cathode current collector layer, wherein the lithium metal layer comprises lithium deposits.

Images