Anode interlayer for all-solid-state batteries and all-solid-state battery manufacturing method

Abstract

The all-solid-state battery cell manufacturing method includes depositing an intermediate layer directly on an anode current collector; depositing a solid electrolyte on the intermediate layer opposite the anode current collector; forming a cathode on the solid electrolyte opposite the intermediate layer, the cathode containing one or more lithium-containing compounds; and applying pressure to achieve uniform contact between the layers. The all-solid-state battery cell manufactured is anode-free before charging. The intermediate layer is configured such that lithium metal is deposited between the intermediate layer and the anode current collector during charging, the intermediate layer prevents contact between the lithium metal and the solid electrolyte, and the intermediate layer has a density greater than that of the solid electrolyte.

Description

[Technical Field]

[0001] The present disclosure relates to an intermediate layer provided between a solid electrolyte and an anode current collector of an all-solid-state battery and a method for manufacturing the all-solid-state battery. [Background technology]

[0002] Progress has been made toward high-energy density batteries, including both lithium metal and lithium-ion batteries. However, these advances are limited by the choice of underlying materials and electrochemistry. Traditional lithium-ion batteries use either organic liquid electrolytes, which tend to react adversely with the active materials and are potentially flammable, or ionic liquid electrolytes, which have increased viscosity and lower ionic conductivity. All-solid-state batteries can address some or all of these issues while producing higher energy densities. However, large interfacial resistance at the electrolyte / electrode interface and interfacial stability and compatibility due to lithium reactivity affect the electrochemical performance of the battery. Non-uniform lithium plating, lithium dendrite formation, and side reactions between lithium metal and the solid electrolyte contribute to performance degradation. Summary of the Invention

[0003] Disclosed herein are all-solid-state battery cells having an anode interlayer, all-solid-state batteries including multiple battery cells, and implementations of anode-free all-solid-state battery cell fabrication methods.

[0004] As disclosed herein, an all-solid-state battery cell can include an anode current collector, a solid electrolyte, and an intermediate layer between the anode current collector and the solid electrolyte, configured such that lithium metal is deposited between the intermediate layer and the anode current collector during charging, the intermediate layer prevents contact between the lithium metal and the solid electrolyte, and the intermediate layer has a density greater than that of the solid electrolyte.

[0005] The all-solid-state battery cell manufacturing method includes depositing an intermediate layer directly on an anode current collector; depositing a solid electrolyte on the intermediate layer opposite the anode current collector; forming a cathode on the solid electrolyte opposite the intermediate layer, the cathode containing one or more lithium-containing compounds; and applying pressure to achieve uniform contact between the layers. The manufactured all-solid-state battery cell is anode-free before charging. The intermediate layer is configured such that lithium metal is deposited between the intermediate layer and the anode current collector during charging, the intermediate layer prevents contact between the lithium metal and the solid electrolyte, and the intermediate layer has a density greater than that of the solid electrolyte.

[0006] These and other aspects, features, elements, implementations, and embodiments of the methods and apparatus disclosed herein are described in further detail hereinafter.

[0007] The present disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not to scale. To the contrary, dimensions of the various features have been arbitrarily increased or reduced for clarity. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional schematic diagram of an anode-free ASSB as disclosed herein.

[0009] [Figure 2] FIG. 2 is a cross-sectional schematic diagram of the anode-free ASSB of FIG. 1 after one charging cycle.

[0010] [Figure 3] FIG. 3 is a flow diagram of the anode-free ASSB manufacturing method.

[0011] [Figure 4]FIG. 4 is a cross-section of an ASSB cell without the disclosed interlayer after one charge cycle, taken with a scanning electron microscope (SEM).

[0012] [Figure 5] FIG. 5 is a cross-section of an ASSB cell including a disclosed interlayer after one charge cycle taken by SEM, showing the interlayer enlarged.

[0013] [Figure 6] FIG. 6 is a graph of current density versus potential illustrating how the interlayer protects the solid electrolyte from decomposition caused by lithium metal reactivity.

[0014] [Figure 7] FIG. 7 is a graph of voltage versus area specific capacity for the same ASSB cell as in FIG. 6, illustrating how an intermediate layer improves the capacity of the ASSB.

[0015] [Figure 8] 8A and 8B compare the energy densities of two different ASSB cells by comparing charging at 1 mV / s and 10 mV / s. In FIG. 8A, the ASSB cell is formed with a 10 μm thick Ag—C interlayer. In FIG. 8B, the ASSB cell is formed with an interlayer disclosed herein. DETAILED DESCRIPTION OF THE INVENTION

[0016] All-solid-state batteries (ASSBs) offer higher volumetric and gravimetric energy densities than conventional lithium-ion batteries. Lithium metal anodes have a theoretical gravimetric capacity roughly 10 times higher than graphite-based anodes. However, the uneven electrodeposition of lithium, which leads to dendrite formation, has prevented the widespread use of lithium metal batteries. During battery operation, lithium is continuously deposited or removed depending on the charge / discharge cycle. As lithium deposits, it does not deposit uniformly; instead, dendrites, small, rigid, branch-like structures with needle-like protrusions, can form. The formation of dendrites creates an uneven lithium surface, which further exacerbates the uneven lithium deposition. As dendrites grow from this uneven deposition, battery degradation can occur. Gaps can form between the lithium and the solid electrolyte, resulting in a loss of contact between the solid electrolyte and the lithium metal. Both the low density of lithium dendrite deposits and the loss of contact between the layers increase cell expansion during charging. If lithium dendrites reach the other electrode, a short circuit in the battery can occur. Additionally, side reactions between lithium metal and the solid electrolyte can further contribute to performance degradation.

[0017] Disclosed herein is an all-solid-state battery cell having an anode interlayer interlayer between an ASSB anode current collector and a solid electrolyte. The interlayer is formed directly on the anode current collector, and a solid electrolyte is deposited on the interlayer. The interlayer distributes lithium evenly and densely between the interlayer and the anode current collector during charging. The interlayer maintains uniform contact with the solid electrolyte. Dense lithium plating and maintaining contact between the layers reduces cell expansion during charging and improves volumetric energy density.

[0018] An ASSB cell 100 as disclosed is illustrated schematically in cross-section in FIG. 1. The ASSB cell 100 of FIG. 1 is configured as a layered battery cell including a cathode 102 having an active cathode material layer as an active layer, a solid electrolyte 104, and an anode current collector 106. An intermediate layer 108 as disclosed herein is formed on the anode current collector 106 between the anode current collector 106 and the solid electrolyte 104. Additionally, the ASSB cell 100 of FIG. 1 may include a cathode current collector 110 configured such that the active layer is interposed between the anode current collector 106 and the cathode current collector 110. An ASSB may be composed of multiple ASSB cells 100.

[0019] The anode current collector 106 may be, by way of non-limiting example, a sheet or foil made of non-corrosive stainless steel, such as SUS 304.

[0020] The solid electrolyte 104 may be, by way of non-limiting example, sulfide compounds (e.g., silver germanite, LGPS, LPS, etc.), garnet-structured oxides (e.g., LLZO with various dopants), NASICON-type phosphate glass ceramics (LAGP), oxynitrides (e.g., lithium phosphorus oxynitride or LIPON), and polymers (PEO).

[0021] The cathode current collector 110 may be, by way of non-limiting example, an aluminum sheet or foil, carbon paper, or graphene paper.

[0022] The cathode active material layer 102 has a cathode active material that may include one or more lithium transition metal oxides and lithium transition metal phosphates, which may be bound together using a binder and optionally a conductive filler, such as carbon black. The lithium transition metal oxides and lithium transition metal phosphates include, but are not limited to, LiCoO, LiNiO, LiNi 0.8 Co 0.15 Al 0.05O2, LiMnO2, Li(Ni 0.5 Mn 0.5 )O2, LiNi x Co y Mn z O2, spinel Li2Mn2O4, LiFePO4 and other polyanionic compounds, as well as LiMnPO4, LiCoPO4, LiNi 0.5 Co 0.5 PO4, and LiMn 0.33 Fe 0.33 Co 0.33 Other olivine structures including PO4 may be included. The cathode active material layer 102 may be a sulfur-based active material, which may include, by way of non-limiting example, LiSO2, LiSO2Cl2, LiSOCl2, and LiFeS2.

[0023] Figure 1 illustrates an anode-free ASSB cell 100 disclosed herein in its as-manufactured state, prior to charging. Figure 2 illustrates the ASSB cell 100 after at least one charge, in which lithium from the lithium-containing cathode material of the cathode 102 is deposited between the interlayer 108 and the anode current collector 106 upon charging, forming a lithium metal anode 112. It is noted that some of the interlayer material, less than 1.0%, may remain on the anode current collector during charging.

[0024] The interlayer 108 has a density greater than that of the solid electrolyte 104. This dense interlayer 108 uniformly distributes lithium ions, forming a densely packed lithium layer in the anode 112, as shown in FIG. 2 . The lithium ion conductivity of the interlayer 108 is greater than the electronic conductivity of the interlayer 108. This ratio of ionic to electronic conductivity prevents electrons from permeating through the interlayer 108 and allows lithium ions to plate between the interlayer 108 and the anode current collector 106 in the anode 112. If electrons were able to permeate through the interlayer 108 to reach the solid electrolyte 104, lithium would plate at the interface between the interlayer 108 and the solid electrolyte 104, resulting in a side reaction at the lithium / solid electrolyte 104 interface.

[0025] Interlayer 108 may be about 100 nm or thicker. Because it is preferable to keep the cell thickness to a minimum, the thickness of interlayer 108 may be as thin as possible while still providing the necessary benefits for performance.

[0026] The intermediate layer 108 between the solid electrolyte 104 and the anode current collector 106 comprises one or more ionically conductive materials that have a stable potential window of 0 V to 2.0 V relative to lithium. Stability relative to lithium metal indicates that the material is inert to lithium. A material is said to be stable if it does not undergo spontaneous reaction with lithium at 0 V. A material that is stable relative to lithium has a reduction potential (relative to lithium) at or near 0 V. The ionically conductive materials herein are stable or nearly stable relative to lithium.

[0027] Ionic conductivity is the property most often used to study ion migration in solids. The ionic conductivity of a solid measures how easily ions can move from one side to the other through defects in the crystal lattice. Ionic conductivity clearly depends on the crystal structure, but it is also affected by the microstructure resulting from processing the solid. To address material properties that are independent of processing conditions, the lithium ion migration energy, or lithium ion migration barrier, is used as a measure of ion migration in lithium compounds. The ionically conductive materials herein have low migration barriers, with an approximate migration barrier or approximate lithium ion migration energy of 0.5 eV or less. The intermediate layer 108 includes LiCl, LiBr, Li2O, Li2Se, LiF, Li2S, LiI, Li2IBr, Sr4Li(BN2)3, LiYO2, LiNbO2, Li LaO2, LiGdO2, Li8HfO6, LiErO2, CsLi2Cl3, Cs3Li2I5, LiHoO2, LiTmO2, LiDyO2, Li7La3Hf2O 12 and Li7VN4. The intermediate layer 108 materials and their associated estimated migration barriers are shown in Table 1 below. [Table 1]

[0028] The intermediate layer 108 disclosed herein is configured such that during charging, lithium metal is deposited between the intermediate layer 108 and the anode current collector 112, and the intermediate layer 108 prevents contact between the lithium metal and the solid electrolyte 104.

[0029] Also disclosed herein is a method of making an ASSB cell 100. The method of manufacturing an ASSB cell is shown in the flow diagram of FIG. 3 and includes depositing an interlayer 108 directly onto an anode current collector 106. The deposition method may be, for example, electron beam evaporation. Depositing the interlayer 108 directly onto the anode current collector 106 allows for a thin, uniform, and dense layer. If the interlayer 108 were deposited on a lithium metal anode before charging, lithium would be too reactive and the interlayer would not be uniform. If the interlayer 108 were deposited on a solid electrolyte 104, the air sensitivity of the solid electrolyte would prevent a dense and uniform interlayer.

[0030] After the intermediate layer 108 is deposited, the solid electrolyte 104 is deposited on the intermediate layer 108 on the side opposite the anode current collector 106. The cathode 102 is formed on the solid electrolyte 104 on the side opposite the intermediate layer 108. If a cathode current collector 110 is used, it may be applied. The order of layer deposition may be modified as long as the intermediate layer is deposited on the anode current collector. Pressure is applied to the stack to achieve uniform contact between the layers. The manufactured all-solid-state battery cell is anode-free before charging. The intermediate layer is configured so that lithium metal is deposited between the intermediate layer and the anode current collector during charging, the intermediate layer prevents contact between the lithium metal and the solid electrolyte, and the intermediate layer has a density greater than that of the solid electrolyte. The anode-free ASSB cell is easy to fabricate and can be mass-produced.

[0031] FIG. 4 is a close-up of a cross-section of an ASSB cell without a disclosed interlayer after one charge cycle. As can be seen, lithium metal 200 is neither uniformly nor densely deposited. Large gaps 202 between the lithium metal 200 and the solid electrolyte 204 are evident. FIG. 5 is a close-up of a cross-section of an ASSB cell including a disclosed interlayer, here formed of LiCl. The close-up clearly shows a smooth, dense interlayer 208 between dense, uniformly plated lithium metal 210 after one charge cycle. There are no gaps between the interlayer 208 and the solid electrolyte 212.

[0032] ASSB cells without and with an interlayer were fabricated. The interlayer material was LiCl. The ASSB cells were cycled 200 times. Significant durability improvements were observed in the ASSB cells with an interlayer. Figure 6 is a graph of current density versus potential, illustrating how the interlayer protects the solid electrolyte from decomposition caused by lithium-metal reactivity. Figure 7 is a graph of potential versus area-specific capacity for the same ASSB cell, illustrating how the interlayer improves the capacity of the ASSB.

[0033] 8A and 8B compare the energy densities of two different ASSB cells by comparing charging at 1 mV / s and 10 mV / s. In FIG. 8A, an ASSB cell is formed with a 10 μm thick Ag-C interlayer, an NMC cathode, and a ligno-silver-sulfite (LPSCI) electrolyte. In FIG. 8B, an ASSB cell as disclosed herein is formed with a 1 μm thick LiCl interlayer, an NMC cathode, and a ligno-silver-sulfite (LPSCI) electrolyte. The ASSB cell in FIG. 8A exhibits significant delay at the 10 mV / s rate, indicating a delay in rapid charging. The ASSB cell in FIG. 8B exhibits no difference between the two scan rates, demonstrating rapid chargeability and high energy density.

[0034] As used herein, the terms "example," "embodiment," "implementation," "aspect," "feature," or "element" indicate that they serve as an example, instance, or illustration. Unless expressly stated otherwise, any example, embodiment, implementation, aspect, feature, or element is independent of each other example, embodiment, implementation, aspect, feature, or element and may be used in combination with any other example, embodiment, implementation, aspect, feature, or element.

[0035] The present disclosure includes the following embodiments. Embodiment 1 1. An all-solid-state battery cell comprising: an anode current collector; with a solid electrolyte; an intermediate layer between the anode current collector and the solid electrolyte, the intermediate layer comprising: Upon charging, lithium metal is deposited between the intermediate layer and the anode current collector; the intermediate layer prevents contact between the lithium metal and the solid electrolyte; The intermediate layer has a density greater than the density of the solid electrolyte. The intermediate layer and The all-solid-state battery cell. Embodiment 2 2. The all-solid-state battery cell of embodiment 1, wherein the lithium ion conductivity of the intermediate layer is greater than the electronic conductivity of the intermediate layer. Embodiment 3 2. The all-solid-state battery cell according to embodiment 1, wherein the intermediate layer is made of a material having a stable potential window of 0 V to 2.0 V with respect to lithium. Embodiment 4 2. The all-solid-state battery cell of embodiment 1, wherein the intermediate layer has a thickness of at least 100 nm. Embodiment 5 The intermediate layer is made of LiCl, LiBr, Li 2 O, Li 2 Se, LiF, Li 2 S, LiI, Li 2 IBr, Sr 4 Li(BN 2 ) 3 , LiYO 2 , LiNbO 2 , LiLaO 2 , LiGdO 2 , Li 8 HfO 6 , LiErO 2 , CsLi 2 Cl 3 , Cs 3 Li 2 I 5 , LiHoO 2 , LiTmO 2 , LiDyO 2 , Li 7 La 3 Hf 2 O 12 , and Li 7 VN 4 2. The all-solid-state battery cell of embodiment 1, selected from the group consisting of: Embodiment 6 2. The all-solid-state battery cell of embodiment 1, wherein the intermediate layer is LiCl. Embodiment 7 2. The all-solid-state battery cell of embodiment 1, further comprising a cathode and a cathode current collector. Embodiment 8 1. A method of manufacturing an all-solid-state battery cell, comprising: depositing an intermediate layer directly onto an anode current collector; depositing a solid electrolyte on the intermediate layer opposite the anode current collector; forming a cathode on the solid electrolyte opposite the intermediate layer, the cathode comprising one or more lithium-containing compounds; applying pressure to achieve uniform contact between the layers; Including, the fabricated all-solid-state battery cell is anode-free before charging; the intermediate layer is configured such that during charging, lithium metal is deposited between the intermediate layer and the anode current collector, the intermediate layer prevents contact between the lithium metal and the solid electrolyte, and the intermediate layer has a density greater than that of the solid electrolyte. Embodiment 9 9. The method of embodiment 8, wherein the deposition of the intermediate layer is carried out using electron beam evaporation. Embodiment 10 9. The method of embodiment 8, wherein the lithium ionic conductivity of the intermediate layer is greater than the electronic conductivity of the intermediate layer. Embodiment 11 9. The method of embodiment 8, wherein the intermediate layer is a material having a stable potential window of 0 V to 2.0 V with respect to lithium. Embodiment 12 9. The method of embodiment 8, wherein the intermediate layer has a thickness of at least 100 nm. Embodiment 13 The intermediate layer is made of LiCl, LiBr, Li 2 O, Li 2 Se, LiF, Li 2 S, LiI, Li 2 IBr, Sr 4 Li(BN 2 ) 3 , LiYO 2 , LiNbO 2 , LiLaO 2 , LiGdO 2 , Li 8 HfO 6 , LiErO 2 , CsLi 2 Cl 3 , Cs 3 Li 2 I 5 , LiHoO 2 , LiTmO 2 , LiDyO 2 , Li 7 La 3 Hf 2 O 12 , and Li 7 VN 4 9. The method of embodiment 8, wherein the compound is selected from the group consisting of: Embodiment 14 9. The method of embodiment 8, wherein the intermediate layer is LiCl. Embodiment 15 9. The method of embodiment 8, wherein the anode current collector is stainless steel. Although the present disclosure has been described in connection with particular embodiments, the present disclosure is not limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under law.

Claims

1. 1. An all-solid-state battery cell comprising: an anode current collector; a solid electrolyte; an intermediate layer between the anode current collector and the solid electrolyte, the intermediate layer being selected from the group consisting of LiCl, LiBr, Li2Se, Li2IBr, Sr4Li(BN2)3, LiYO2, LiLaO2, LiGdO2, Li8HfO6, LiErO2, CsLi2Cl3, Cs3Li2I5, LiHoO2, LiTmO2, LiDyO2, Li7La3Hf2O12, and Li7VN4; Upon charging, lithium metal is deposited between the intermediate layer and the anode current collector; the intermediate layer prevents contact between the lithium metal and the solid electrolyte; The intermediate layer has a density greater than the density of the solid electrolyte. The intermediate layer and The all-solid-state battery cell.

2. 2. The all-solid-state battery cell according to claim 1, wherein the lithium ion conductivity of the intermediate layer is greater than the electronic conductivity of the intermediate layer.

3. 2. The all-solid-state battery cell according to claim 1, wherein the intermediate layer is made of a material having a stable potential window of 0 V to 2.0 V with respect to lithium.

4. 10. The all-solid-state battery cell of claim 1, wherein the intermediate layer has a thickness of at least 100 nm.

5. 10. The all-solid-state battery cell of claim 1, wherein the intermediate layer is LiCl.

6. 10. The all-solid-state battery cell of claim 1, further comprising a cathode and a cathode current collector.

7. 1. A method for manufacturing an all-solid-state battery cell, comprising: depositing an intermediate layer selected from the group consisting of LiCl, LiBr, Li2Se, Li2IBr, Sr4Li(BN2)3, LiYO2, LiLaO2, LiGdO2, Li8HfO6, LiErO2, CsLi2Cl3, Cs3Li2I5, LiHoO2, LiTmO2, LiDyO2, Li7La3Hf2O12, and Li7VN4 directly onto the anode current collector; depositing a solid electrolyte on the intermediate layer opposite the anode current collector; forming a cathode on the solid electrolyte opposite the intermediate layer, the cathode comprising one or more lithium-containing compounds; applying pressure to achieve uniform contact between the layers; Including, the produced all-solid-state battery cell is anode-free before charging; the intermediate layer is configured such that during charging, lithium metal is deposited between the intermediate layer and the anode current collector, the intermediate layer prevents contact between the lithium metal and the solid electrolyte, and the intermediate layer has a density greater than that of the solid electrolyte.

8. The method of claim 7 , wherein the deposition of the intermediate layer is performed using electron beam evaporation.

9. The method of claim 7 , wherein the lithium ion conductivity of the intermediate layer is greater than the electronic conductivity of the intermediate layer.

10. 8. The method according to claim 7, wherein the intermediate layer is a material having a stable potential window of 0 V to 2.0 V with respect to lithium.

11. The method of claim 7 , wherein the intermediate layer has a thickness of at least 100 nm.

12. 8. The method of claim 7, wherein the intermediate layer is LiCl.

13. The method of claim 7 wherein the anode current collector is stainless steel.

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