Solid electrolyte, method of manufacturing same, and lithium battery including same

Abstract

A solid electrolyte, a method of manufacturing the same, and a lithium battery including the solid electrolyte. The solid electrolyte may include a solid ion conductor represented by Formula 1, where in Formula 1, Q is an element having an ionic radius different from that of Al by less than 30% and having a valence of + 3 and + 5, X is at least one of F, Cl, Br, or I, 3.5 < = a < = 4.5, 3 < = b < 5.2, 1 < = m < = 3, 0 < n < 2, 11 < = c < = 13, and 0 < d < = 1.5. The formula 1 is Li B Al < m > Q < n > O < c > X < d >.

Description

[0001] Cross - reference to related applications

[0002] This application is based on and claims priority and all resulting benefits from Korean Patent Application No. 10 - 2024 - 0009792, filed with the Korean Intellectual Property Office on January 22, 2024, the entire content of which is incorporated herein by reference. Technical field

[0003] The present disclosure relates to a solid electrolyte, a method of manufacturing the same, and a lithium battery including the solid electrolyte. Background art

[0004] Lithium batteries generally have a high energy density per unit volume and are thus widely used in automobiles and various portable electronic devices. However, currently used lithium batteries have a liquid electrolyte, which has safety problems related to ignition.

[0005] To improve the safety of lithium batteries, the use of polymer solid electrolytes, sulfide solid electrolytes, and oxide solid electrolytes instead of liquid electrolytes has been a focus of research. Polymer solid electrolytes are typically affected by thermal stability and can thus deteriorate at high temperatures. Sulfide solid electrolytes often have high reactivity in air or with the positive electrode active material and can thus be difficult to handle independently. Oxide solid electrolytes generally have low ionic conductivity and high sintering temperatures, and thus, when manufacturing a lithium battery, the oxide solid electrolyte can react at the interface between the solid electrolyte and the electrode active material, resulting in a rapid decrease in battery performance.

[0006] Therefore, there is still a need for a solid electrolyte, a method of manufacturing the same, and a lithium battery including the same that can provide high density and high ionic conductivity at a low sintering temperature. Summary of the invention

[0007] There is provided a solid electrolyte that can achieve high density and high ionic conductivity at a low sintering temperature.

[0008] There is provided a method of manufacturing the solid electrolyte.

[0009] There is provided a lithium battery including the solid electrode.

[0010] Additional aspects will be set forth in part in the following description, and in part will be obvious from the description, or may be learned by practice of the presented embodiments of the present disclosure.

[0011] According to an aspect of the present disclosure, a solid electrolyte includes a solid ion conductor represented by Formula 1:

[0012] Formula 1

[0013] Li a B b Al m Q n O c X d

[0014] Among them, in Formula 1, Q is an element having an ionic radius with a difference of less than 30% from the ionic radius of Al and having +3 and +5 valence states (or having a +3 valence state), X is at least one of F, Cl, Br, or I, 3.5 ≤ a ≤ 4.5, 3 ≤ b < 5.2, 1 ≤ m ≤ 3, 0 < n < 2, 11 ≤ c ≤ 13, and 0 < d ≤ 1.5.

[0015] According to an embodiment, in Formula 1, the ionic radius of Q can be from about 50 picometers (pm) to about 100 pm.

[0016] According to an embodiment, in Formula 1, Q can include at least one of Sb or V.

[0017] According to an embodiment, in Formula 1, Q can be a substitutional dopant that substitutes for at least one of B or Al in Formula 1.

[0018] According to an embodiment, in Formula 1, 0 < n < 1.

[0019] According to an embodiment, the solid ion conductor can include at least one of the following: Li4B 5.1 Al 1.8 Sb 0.1 O 12 F, Li4B5Al 1.8 Sb 0.2 O 12 F, Li4B 4.9 Al 1.8 Sb 0.3 O 12 F, Li4B 4.8 Al 1.8 Sb 0.4 O 12 F, Li4B 4.7 Al 1.8 Sb 0.5 O 12 F, Li4B 4.6 Al 1.8 Sb 0.6 O 12 F, Li4B 4.5 Al 1.8 Sb 0.7 O 12 F, Li4B 4.4 Al 1.8 Sb 0.8 O 12 F, Li4B4.3 Al 1.8 Sb 0.9 O 12 F,

[0020] Li4B 5.1 Al 1.8 Sb 0.1 O 12 Cl, Li4B5Al 1.8 Sb 0.2 O 12 Cl, Li4B 4.9 Al 1.8 Sb 0.3 O 12 Cl, Li4B 4.8 Al 1.8 Sb 0.4 O 12 Cl, Li4B 4.7 Al 1.8 Sb 0.5 O 12 Cl, Li4B 4.6 Al 1.8 Sb 0.6 O 12 Cl, Li4B 4.5 Al 1.8 Sb 0.7 O 12 Cl, Li4B 4.4 Al 1.8 Sb 0.8 O 12 Cl, Li4B 4.3 Al 1.8 Sb 0.9 O 12 Cl,

[0021] Li4B 5.1 Al 1.8 Sb 0.1 O 12 Br, Li4B5Al 1.8 Sb 0.2 O 12 Br, Li4B 4.9 Al 1.8 Sb 0.3 O 12 Br, Li4B 4.8 Al 1.8 Sb 0.4 O 12 Br, Li4B 4.7 Al 1.8 Sb 0.5 O 12 Br, Li4B 4.6 Al1.8 Sb 0.6 O 12 Br, Li4B 4.5 Al 1.8 Sb 0.7 O 12 Br, Li4B 4.4 Al 1.8 Sb 0.8 O 12 Br, Li4B 4.3 Al 1.8 Sb 0.9 O 12 Br,

[0022] Li4B 5.1 Al 1.8 Sb 0.1 O 12 I, Li4B5Al 1.8 Sb 0.2 O 12 I, Li4B 4.9 Al 1.8 Sb 0.3 O 12 I, Li4B 4.8 Al 1.8 Sb 0.4 O 12 I, Li4B 4.7 Al 1.8 Sb 0.5 O 12 I, Li4B 4.6 Al 1.8 Sb 0.6 O 12 I, Li4B 4.5 Al 1.8 Sb 0.7 O 12 I, Li4B 4.4 Al 1.8 Sb 0.8 O 12 I, Li4B 4.3 Al 1.8 Sb 0.9 O 12 I,

[0023] Li4B 5.1 Al 1.8 V 0.1 O 12 F, Li4B5Al 1.8 V 0.2 O 12 F, Li4B 4.9 Al 1.8 V 0.3 O12 F, Li4B 4.8 Al 1.8 V 0.4 O 12 F, Li4B 4.7 Al 1.8 V 0.5 O 12 F, Li4B 4.6 Al 1.8 V 0.6 O 12 F, Li4B 4.5 Al 1.8 V 0.7 O 12 F, Li4B 4.4 Al 1.8 V 0.8 O 12 F, Li4B 4.3 Al 1.8 V 0.9 O 12 F,

[0024] Li4B 5.1 Al 1.8 V 0.1 O 12 Cl, Li4B5Al 1.8 V 0.2 O 12 Cl, Li4B 4.9 Al 1.8 V 0.3 O 12 Cl, Li4B 4.8 Al 1.8 V 0.4 O 12 Cl, Li4B 4.7 Al 1.8 V 0.5 O 12 Cl, Li4B 4.6 Al 1.8 V 0.6 O 12 Cl, Li4B 4.5 Al 1.8 V 0.7 O 12 Cl, Li4B 4.4 Al 1.8 V 0.8 O 12 Cl, Li4B 4.3 Al 1.8 V 0.9 O 12 Cl,

[0025] Li4B5.1 Al 1.8 V 0.1 O 12 Br, Li4B5Al 1.8 V 0.2 O 12 Br, Li4B 4.9 Al 1.8 V 0.3 O 12 Br, Li4B 4.8 Al 1.8 V 0.4 O 12 Br, Li4B 4.7 Al 1.8 V 0.5 O 12 Br, Li4B 4.6 Al 1.8 V 0.6 O 12 Br, Li4B 4.5 Al 1.8 V 0.7 O 12 Br, Li4B 4.4 Al 1.8 V 0.8 O 12 Br, Li4B 4.3 Al 1.8 V 0.9 O 12 Br,

[0026] Li4B 5.1 Al 1.8 V 0.1 O 12 I, Li4B5Al 1.8 V 0.2 O 12 I, Li4B 4.9 Al 1.8 V 0.3 O 12 I, Li4B 4.8 Al 1.8 V 0.4 O 12 I, Li4B 4.7 Al 1.8 V 0.5 O 12 I, Li4B 4.6 Al 1.8 V 0.6 O 12 I, Li4B 4.5 Al 1.8 V 0.7 O 12 I, Li4B4.4 Al 1.8 V 0.8 O 12 I, or Li4B 4.3 Al 1.8 V 0.9 O 12 I.

[0027] According to an embodiment, the solid ion conductor may be at least one of a vitreous (glass-like) solid ion conductor or a crystalline solid ion conductor.

[0028] According to an embodiment, when measured by differential scanning calorimetry of the solid ion conductor, the solid electrolyte may have a crystallization temperature (T c ) of about 400 °C to about 600 °C and a glass transition temperature (T g ).

[0029] According to an embodiment, when measured by a gas pycnometer, the solid ion conductor may have a density of about 1.5 g / cm 3 ) to about 3.0 g / cm 3 .

[0030] According to an embodiment, the solid ion conductor may have an ionic conductivity of about 3.4 x 10 -6 Siemens / cm (S cm -1 ) to about 5.0 x 10 -6 S cm -1 at 25 °C.

[0031] According to an embodiment, the solid ion conductor may further include a composite solid ion conductor, and the composite solid ion conductor further includes a crystalline solid ion conductor represented by Formula 2:

[0032] Formula 2

[0033] Li a1 B b1 Al m1 O c1 X d1

[0034] wherein, in Formula 2, X may be at least one of F, Cl, Br, or I, 3.5 ≤ a1 ≤ 4.5, 3 ≤ b1 ≤ 5.2, 1 ≤ m1 ≤ 3, 11 ≤ c1 ≤ 13, and 0 ≤ d1 ≤ 1.5.

[0035] According to an embodiment, in the composite solid ion conductor, the volume ratio of the solid ion conductor represented by Formula 1 to the solid ion conductor represented by Formula 2 may be about 97:3 to about 50:50.

[0036] According to an embodiment, the solid electrolyte may have a thickness of from about 0.1 micrometers (μm) to about 30 μm.

[0037] According to another aspect of the present disclosure, a method of manufacturing a solid ion conductor includes mechanically grinding a lithium source, a boron source, an aluminum source, a Q element source, and a halogen source to provide a vitreous solid ion conductor, and heat-treating the vitreous solid ion conductor at a temperature equal to or higher than an initial thermal decomposition temperature (T s ) measured by a differential scanning calorimeter (DSC) to provide a crystalline-containing solid ion conductor represented by Formula 1

[0038] Formula 1

[0039] Li a B b Al m Q n O c X d

[0040] wherein, in Formula 1, Q is an element having an ionic radius that differs from that of Al by less than 30% and having +3 and +5 valence states (or having a +3 valence state), X is at least one of F, Cl, Br, or I, 3.5 ≤ a ≤ 4.5, 3 ≤ b < 5.2, 1 ≤ m ≤ 3, 0 < n < 2, 11 ≤ c ≤ 13, and 0 < d ≤ 1.5.

[0041] According to an embodiment, the providing of the vitreous solid ion conductor may further include, after mechanical grinding, pre-heat-treating and quenching at a temperature in the range of from about 600 °C to about 1,300 °C.

[0042] According to an embodiment, the Q element source may include at least one of Sb2O3, Sb2O5, V2O3, V2O5, SbF3, SbF5, SbCl3, SbCl5, SbCl2F3, SbCl3F2, Sb(NO3)3, Sb(OH)3, or Sb(OH)5.

[0043] According to an embodiment, the manufacturing of the crystalline-containing solid ion conductor may include heat-treating the vitreous solid ion conductor in an air atmosphere, or providing insulating films on both sides of the vitreous solid ion conductor and then heat-treating.

[0044] According to an embodiment, in the manufacturing of the crystalline-containing solid ion conductor, the vitreous solid ion conductor may be heat-treated at a temperature of 600 °C or lower for about 5 minutes to about 2 hours.

[0045] According to an embodiment, in the manufacture of the crystalline-containing solid ion conductor, an insulating film may be disposed on both sides of the vitreous solid ion conductor, and heat treatment may be performed at a pressure of about 1 megapascal (MPa) to about 50 MPa and a temperature of about 400 °C to about 600 °C.

[0046] According to another aspect of the present disclosure, a lithium battery includes a positive electrode, a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode, wherein at least one of the positive electrode, the negative electrode, or the solid electrolyte layer includes the solid electrolyte.

[0047] According to an embodiment, the lithium battery may be a lithium-ion battery, an all-solid-state battery, or a multilayer ceramic (MLC) battery.

[0048] According to an embodiment, the lithium battery may include: a plurality of positive electrodes, each including a positive electrode current collector and positive electrode active material layers disposed on both sides of the positive electrode current collector; a plurality of negative electrodes, each including a negative electrode current collector and negative electrode active material layers disposed on both sides of the negative electrode current collector, wherein the plurality of negative electrodes are alternately disposed between the plurality of positive electrodes; and a solid electrolyte alternately disposed between the plurality of positive electrodes and the plurality of negative electrodes, wherein at least one of the positive electrode active material layer or the negative electrode active material layer includes the solid electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The above and other aspects, features, and advantages of some embodiments of the present disclosure will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:

[0050] Figure 1 FIG. is a schematic cross-sectional view showing an embodiment of a multilayer ceramic (MLC) battery;

[0051] Figure 2 FIG. is a schematic cross-sectional view showing an embodiment of an MLC battery;

[0052] Figure 3 FIG. is a schematic cross-sectional view showing an embodiment of an MLC battery;

[0053] Figure 4 FIG. is a graph showing the intensity (arbitrary unit, a.u.) of the X-ray diffraction (XRD) spectrum of the vitreous solid ion conductor for Comparative Example 1 and Examples 1 to 4 versus the diffraction angle (degrees, 2θ) before heat treatment;

[0054] Figure 5 FIG. is a graph showing the intensity (arbitrary unit) of the XRD spectrum of the crystalline-containing ceramic solid ion conductor for Comparative Example 1 and Examples 1 to 4 versus the diffraction angle (degrees, 2θ) after heat treatment;

[0055] Figure 6 Graph of heat flow (arbitrary units) versus temperature (°C) for differential scanning calorimetry (DSC) spectra of the vitreous solid ion conductors of Examples 1, 2, and 4;

[0056] Figures 7A to 7D Scanning electron microscope photographs (SEM) of the fracture surfaces of the vitreous solid ion conductor cullets of Examples 1 to 4, respectively, wherein the fracture surfaces were obtained by: heat treatment at a temperature of 550 °C and a pressure of 50 MPa with spacers on both sides of the cullet as blocking electrodes, and then breaking the sintered material from the heat treatment with pliers;

[0057] Figure 8 Graph of ionic conductivity (Siemens / cm, S / cm) and ionic conductivity / electronic conductivity versus x of Li4B 5.2-x Al 1.8 Sb x O 12 Cl, where the specimen was prepared by heat treatment of the cullet of the vitreous solid ion conductor of Example 2 at 550 °C in an air box furnace (hereinafter referred to as "box sintering"); and

[0058] Figure 9 Graph of ionic conductivity (Siemens / cm, S / cm) and ionic conductivity / electronic conductivity versus x of Li4B 5.2-x Al 1.8 Sb x O 12 Cl: After preparing the specimen (which is a box sintered specimen of the cullet of the vitreous solid ion conductor of Example 2), wires were connected to the gold electrodes on both sides of the specimen, and wires were connected to the spacers of the blocking electrodes on both sides of the specimen, where the specimen was prepared by heat treatment of the cullet of the same vitreous solid ion conductor at a temperature of 550 °C and a pressure of 50 MPa with spacers on both surfaces of the blocking electrodes (hereinafter referred to as "hot press sintering" (HPS)). Detailed Description

[0059] Embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings, wherein like reference numerals always refer to like elements. In this regard, the present embodiments may have different forms and should not be construed as limited to the description set forth herein. Accordingly, the embodiments are described below only by way of example with reference to the accompanying drawings. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. The expression such as "at least one (kind) of..." when before or after a list of elements modifies the entire list of elements and does not modify the individual elements of the list.

[0060] The inventive concept described below may have various modifications and various embodiments, and example embodiments will be shown in the accompanying drawings and described more fully in the detailed description. However, the inventive concept should not be construed as limited to the example embodiments set forth herein, but rather, should be understood to cover all modifications, equivalents, or alternatives falling within the scope of the inventive concept.

[0061] As used herein, the terms are for the purpose of describing particular embodiments only and are not intended to limit the inventive concept. Expressions used in the singular form cover the plural form unless they have a clearly different meaning in the context.

[0062] In this specification, the expression "at least one (kind) of" or "one (kind) or more (kinds) of" used before or after a component (part) is intended to supplement the list of all components (parts), and does not mean to supplement the individual component (part) described. Unless otherwise described, the term "combination" used in this specification includes mixtures, alloys, reaction products, etc. Unless otherwise described, the term "comprising" used in this specification does not exclude other components (parts), and means that other components (parts) may be further included. Terms such as "first", "second", etc. used in this specification may be used to distinguish one component (part) from another, without indicating order, quantity, or importance. Unless clearly described or otherwise indicated in the context of this specification, a component (part) should be construed to include the singular and the plural. Unless otherwise specified, the expression "or" includes the meaning of "and / or".

[0063] Throughout this specification, terms such as "embodiment" etc. mean that the specific component (part) described in connection with the embodiment is included in at least one of the embodiments described herein, and the specific component (part) may or may not be present in other embodiments. In addition, the components (parts) described herein should be construed as being combinable in any suitable manner in various embodiments.

[0064] Unless otherwise stated, all percentages, parts, ratios, etc. are by weight. Further, when an equivalent, concentration, or other value or parameter is given as a range, a preferred range, or a list of preferred upper or lower limits, it is to be understood that all ranges formed from any upper range limit or preferred value and any lower range limit, or any pair of preferred values, are specifically disclosed, whether or not the ranges are separately disclosed.

[0065] When a numerical range is stated in this specification, unless otherwise stated, the range is intended to include the endpoints and all integers and fractions within the range. The scope of the present disclosure is not intended to be limited by the specific values recited when defining the range.

[0066] Unless otherwise specified, the unit "parts by weight" refers to the weight ratio between the components, and the unit "parts by mass" refers to the value obtained by converting the weight ratio between the components into the solid content.

[0067] In addition, relative terms such as "lower" or "bottom" and "upper" or "top" may be used herein to describe the relationship of one element to another as shown in the figures. It will be understood that the relative terms are also intended to cover different orientations of the device in addition to the orientation depicted in the figures. For example, if the device in one of the figures is flipped, an element described as on the "lower" side of another element will be oriented on the "upper" side of the other element. Thus, depending on the specific orientation of the figure, the term "lower" may cover both "lower" and "upper" orientations. Similarly, if the device in one of the figures is flipped, an element described as "below" or "beneath" another element will be oriented "above" the other element. Thus, the terms "below" or "beneath" may cover both above and below orientations.

[0068] The term "about" as used in this specification includes the values stated herein and also includes values within an acceptable deviation range of the specific values determined by those skilled in the art in view of the errors associated with the corresponding measurements and the limitations of the measurement system for the specific quantity being measured. For example, the term "about" may include values within one or more standard deviations of a specified value, or values within ±30%, ±20%, ±10%, or ±5%.

[0069] As used herein, the term "amorphous or amorphous material" may refer to a material that lacks any long-range crystalline structure when measured by X-ray diffraction.

[0070] As used herein, the term "ceramic" may include amorphous materials, crystalline ceramics, glass-ceramics, and combinations thereof.

[0071] As used herein, the term "glass (glassy, vitreous)" refers to an amorphous or non-crystalline material that exhibits a glass transition temperature.

[0072] As used herein, the term "glass-ceramic" refers to a crystalline-containing ceramic formed by heat-treating an amorphous or non-crystalline material.

[0073] As used herein, the symbol "T g " refers to the glass transition temperature measured by a differential scanning calorimetry (DSC) experiment.

[0074] As used herein, the symbol "T s " refers to the initial thermal decomposition temperature measured by a DSC experiment.

[0075] As used herein, the symbol "T c " refers to the crystallization temperature measured by a DSC experiment.

[0076] Unless otherwise defined, all terms (including technical and scientific terms) used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In addition, terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the relevant art and this disclosure, and should not be interpreted as idealized. Instead, the terms should not be interpreted in an overly formal sense.

[0077] Exemplary embodiments are described with reference to cross-sectional views that are schematic diagrams of idealized embodiments. Accordingly, the appearance of the examples may vary, for example, due to manufacturing techniques and / or tolerances. Thus, the embodiments described herein should not be construed as limited to the specific shapes of the regions described herein, but should include, for example, variations in shape that occur during manufacturing. For example, regions shown or described as flat may generally have rough and / or non-linear characteristics. In addition, the sharp angles shown may be rounded. Thus, the regions shown in the figures are schematic in nature, and their shapes are not intended to show the exact shape of the regions and are not intended to limit the scope of the claims.

[0078] Generally, an oxide solid electrolyte can be sintered simultaneously with a positive electrode for use in a lithium battery. However, such an oxide solid electrolyte typically has a high sintering temperature, which leads to an interfacial reaction with the positive electrode active material, resulting in a sharp decline in the battery performance of the lithium battery. In addition, when the oxide solid electrolyte is used as a crystalline material, due to the low binding force at the interface with the positive electrode active material, a separation phenomenon occurs between the oxide solid electrolyte and the positive electrode active material.

[0079] A novel composition of a solid electrolyte, a lithium battery containing the same, and a method for manufacturing the solid electrolyte are provided to solve the above problems.

[0080] Hereinafter, a solid electrolyte, a lithium battery including the same, and a method of manufacturing the solid electrolyte will be described in more detail by way of exemplary embodiments.

[0081] Solid electrolyte

[0082] The solid electrolyte according to an embodiment may include a solid ion conductor represented by Formula 1:

[0083] Formula 1

[0084] Li a B b Al m Q n O c X d

[0085] Wherein, in Formula 1, Q may be an element having an ionic radius differing from that of Al by less than 30% and having +3 and +5 valence states (or having a +3 valence state), X may be at least one of F, Cl, Br, or I, 3.5 ≤ a ≤ 4.5, 3 ≤ b < 5.2, 1 ≤ m ≤ 3, 0 < n < 2, 11 ≤ c ≤ 13, and 0 < d ≤ 1.5.

[0086] Generally, a solid ion conductor having a composition of Li4B7O 12 Cl may be vulnerable to moisture (water) and have a low ionic conductivity. Compared with a solid ion conductor having a composition of Li4B7O 12 Cl, a solid ion conductor having a composition of Li4B4Al3O 12 Cl (wherein Al substitutes in the B region of the composition of Li4B7O 12 Cl) may have excellent moisture resistance, but may easily crystallize and may be difficult to vitrify due to devitrification occurring during glass synthesis. As a result, at temperatures below 600 °C, it may be difficult to achieve acceptable adhesion between the electrode active material and the solid electrolyte including the solid ion conductor having a composition of Li4B4Al3O 12 Cl.

[0087] The solid electrolyte according to an embodiment may contain polyvalent atoms, wherein Q in Formula 1 may be an element having +3 and +5 valence states. Q may also substitute for the Al element site, and the difference in ionic radius from Al may create vacancy defects. Such substituted vacancy defects may change the reactivity of the solid electrolyte and also affect the density and ionic conductivity of the solid electrolyte. By substantial doping of the Q element for Al in Formula 1, due to the increased vacancy defects, the solid electrolyte according to an embodiment may have improved ionic conductivity.

[0088] For example, Al, Sb, and V may have a coordination number of 6.

[0089] In the solid electrolyte according to the embodiment, the ionic radius of the Q element in Formula 1 may be about 50 picometers (pm) to about 100 pm, about 53 pm to about 95 pm, about 55 pm to about 90 pm, about 58 pm to about 85 pm, or about 58 pm to about 80 pm. Here, the ionic radius of the Q element refers to the ionic radius of Q 3+ ions.

[0090] In the solid electrolyte according to the embodiment, Q in Formula 1 may include at least one of Sb or V.

[0091] In the solid electrolyte according to the embodiment, Q in Formula 1 may be a substitutional dopant that substitutes for at least one of B or Al in Formula 1. For example, since B and Al each have +3 valence electrons, Q, which can have +5 valence electrons, can substitute for B or Al. In the substitution region, vacancies (or empty lattice points) and Schottky defects (a type of point defect) may be generated. The solid electrolyte including the Schottky defects generated therein may be able to maintain the overall framework structure. However, since the lattice volume may change, and a larger lattice volume may lead to the formation of channels with dimensions more suitable for ion transport, thereby improving the ionic conductivity.

[0092] In the solid electrolyte according to the embodiment, X in Formula 1 may be at least one of F, Cl, Br, or I.

[0093] In the solid electrolyte according to the embodiment, a in Formula 1 may be 3.5 ≤ a ≤ 4.5, 3.6 ≤ a ≤ 4.4, 3.7 ≤ a ≤ 4.3, or 3.8 ≤ a ≤ 4.2.

[0094] In the solid electrolyte according to the embodiment, b in Formula 1 may be 3 ≤ b < 5.2, 3.2 ≤ b ≤ 5.1, 3.4 ≤ b ≤ 5.1, 3.6 ≤ b ≤ 5.1, 3.8 ≤ b ≤ 5.1, 3.9 ≤ b ≤ 5.1, or 4.1 ≤ b ≤ 5.1.

[0095] In the solid electrolyte according to the embodiment, m in Formula 1 may be 1 ≤ m ≤ 3, 1.2 ≤ m ≤ 3, 1.4 ≤ m ≤ 3, 1.6 ≤ m ≤ 3, or 1.8 ≤ m ≤ 3.

[0096] In the solid electrolyte according to the embodiment, n in Formula 1 may be 0 < n < 2, 0 < n < 1.8, 0 < n < 1.6, 0 < n < 1.4, 0 < n < 1.2, 0 < n < 1, 0 < n ≤ 0.8, or 0.1 ≤ n ≤ 0.6. When n in Formula 1 is within the above range, the generation of a second phase (secondary phase) such as LiQO3, Li4AlQO6, and Q2O3 can be minimized when measured by X-ray diffraction analysis.

[0097] In the solid electrolyte according to the embodiment, the solid ion conductor may include Li4B 5.1 Al 1.8 Sb 0.1 O 12 F, Li4B5Al 1.8 Sb 0.2 O 12 F, Li4B 4.9 Al 1.8 Sb 0.3 O 12 F, Li4B 4.8 Al 1.8 Sb 0.4 O 12 F, Li4B 4.7 Al 1.8 Sb 0.5 O 12 F, Li4B 4.6 Al 1.8 Sb 0.6 O 12 F, Li4B 4.5 Al 1.8 Sb 0.7 O 12 F, Li4B 4.4 Al 1.8 Sb 0.8 O 12 F, Li4B 4.3 Al 1.8 Sb 0.9 O 12 F; Li4B 5.1 Al 1.8 Sb 0.1 O 12 Cl, Li4B5Al 1.8 Sb 0.2 O 12 Cl, Li4B 4.9 Al 1.8 Sb 0.3 O 12 Cl, Li4B 4.8 Al 1.8 Sb 0.4O 12 Cl, Li4B 4.7 Al 1.8 Sb 0.5 O 12 Cl, Li4B 4.6 Al 1.8 Sb 0.6 O 12 Cl, Li4B 4.5 Al 1.8 Sb 0.7 O 12 Cl, Li4B 4.4 Al 1.8 Sb 0.8 O 12 Cl, Li4B 4.3 Al 1.8 Sb 0.9 O 12 Cl; Li4B 5.1 Al 1.8 Sb 0.1 O 12 Br, Li4B5Al 1.8 Sb 0.2 O 12 Br, Li4B 4.9 Al 1.8 Sb 0.3 O 12 Br, Li4B 4.8 Al 1.8 Sb 0.4 O 12 Br, Li4B 4.7 Al 1.8 Sb 0.5 O 12 Br, Li4B 4.6 Al 1.8 Sb 0.6 O 12 Br, Li4B 4.5 Al 1.8 Sb 0.7 O 12 Br, Li4B 4.4 Al 1.8 Sb 0.8 O 12 Br, Li4B 4.3 Al 1.8 Sb 0.9 O 12 Br; Li4B 5.1 Al 1.8 Sb 0.1 O 12 I, Li4B5Al 1.8 Sb 0.2 O12 I, Li4B 4.9 Al 1.8 Sb 0.3 O 12 I, Li4B 4.8 Al 1.8 Sb 0.4 O 12 I, Li4B 4.7 Al 1.8 Sb 0.5 O 12 I, Li4B 4.6 Al 1.8 Sb 0.6 O 12 I, Li4B 4.5 Al 1.8 Sb 0.7 O 12 I, Li4B 4.4 Al 1.8 Sb 0.8 O 12 I, Li4B 4.3 Al 1.8 Sb 0.9 O 12 I; Li4B 5.1 Al 1.8 V 0.1 O 12 F, Li4B5Al 1.8 V 0.2 O 12 F, Li4B 4.9 Al 1.8 V 0.3 O 12 F, Li4B 4.8 Al 1.8 V 0.4 O 12 F, Li4B 4.7 Al 1.8 V 0.5 O 12 F, Li4B 4.6 Al 1.8 V 0.6 O 12 F, Li4B 4.5 Al 1.8 V 0.7 O 12 F, Li4B 4.4 Al 1.8 V 0.8 O 12 F, Li4B 4.3 Al 1.8 V 0.9 O 12F; Li4B 5.1 Al 1.8 V 0.1 O 12 Cl, Li4B5Al 1.8 V 0.2 O 12 Cl, Li4B 4.9 Al 1.8 V 0.3 O 12 Cl, Li4B 4.8 Al 1.8 V 0.4 O 12 Cl, Li4B 4.7 Al 1.8 V 0.5 O 12 Cl, Li4B 4.6 Al 1.8 V 0.6 O 12 Cl, Li4B 4.5 Al 1.8 V 0.7 O 12 Cl, Li4B 4.4 Al 1.8 V 0.8 O 12 Cl, Li4B 4.3 Al 1.8 V 0.9 O 12 Cl; Li4B 5.1 Al 1.8 V 0.1 O 12 Br, Li4B5Al 1.8 V 0.2 O 12 Br, Li4B 4.9 Al 1.8 V 0.3 O 12 Br, Li4B 4.8 Al 1.8 V 0.4 O 12 Br, Li4B 4.7 Al 1.8 V 0.5 O 12 Br, Li4B 4.6 Al 1.8 V 0.6 O 12 Br, Li4B 4.5 Al 1.8 V 0.7 O 12 Br, Li4B 4.4Al 1.8 V 0.8 O 12 Br, Li4B 4.3 Al 1.8 V 0.9 O 12 Br; Li4B 5.1 Al 1.8 V 0.1 O 12 I, Li4B5Al 1.8 V 0.2 O 12 I, Li4B 4.9 Al 1.8 V 0.3 O 12 I, Li4B 4.8 Al 1.8 V 0.4 O 12 I, Li4B 4.7 Al 1.8 V 0.5 O 12 I, Li4B 4.6 Al 1.8 V 0.6 O 12 I, Li4B 4.5 Al 1.8 V 0.7 O 12 I, Li4B 4.4 Al 1.8 V 0.8 O 12 I, or Li4B 4.3 Al 1.8 V 0.9 O 12 I. For example, the solid ion conductor may include Li4B 5.1 Al 1.8 Sb 0.1 O 12 Cl, Li4B5Al 1.8 Sb 0.2 O 12 Cl, Li4B 4.9 Al 1.8 Sb 0.3 O 12 Cl, Li4B 4.8 Al 1.8 Sb 0.4 O 12 Cl, Li4B 4.7 Al 1.8 Sb 0.5 O 12 Cl, Li4B 4.6 Al1.8 Sb 0.6 O 12 Cl, Li4B 4.5 Al 1.8 Sb 0.7 O 12 Cl, Li4B 4.4 Al 1.8 Sb 0.8 O 12 Cl, Li4B 4.3 Al 1.8 Sb 0.9 O 12 Cl; Li4B 5.1 Al 1.8 V 0.1 O 12 Cl, Li4B5Al 1.8 V 0.2 O 12 Cl, Li4B 4.9 Al 1.8 V 0.3 O 12 Cl, Li4B 4.8 Al 1.8 V 0.4 O 12 Cl, Li4B 4.7 Al 1.8 V 0.5 O 12 Cl, Li4B 4.6 Al 1.8 V 0.6 O 12 Cl, Li4B 4.5 Al 1.8 V 0.7 O 12 Cl, Li4B 4.4 Al 1.8 V 0.8 O 12 Cl, or Li4B 4.3 Al 1.8 V 0.9 O 12 Cl.

[0098] The solid ion conductor according to the embodiment can be glassy, crystalline, or a combination thereof.

[0099] According to an embodiment, when measured by differential scanning calorimetry (DSC) of the glass-ceramic material, the solid electrolyte can have a crystallization temperature (T c ) of about 400 °C to about 600 °C and a glass transition temperature (T g ) of about 400 °C to about 432 °C. For example, the crystallization temperature Tc It can be 450 °C or higher, 500 °C or higher, or 570 °C or lower, or 550 °C or lower.

[0100] When measured by a gas pycnometer, the solid ion conductor according to the embodiment may have a density of about 1.5 g / cm 3 ) to about 3.0 g / cm 3 . For example, the density of the solid ion conductor can be 1.5 g / cm 3 or greater, 1.8 g / cm 3 or greater, 2.0 g / cm 3 or greater, or 3.0 g / cm 3 or less, 2.7 g / cm 3 or less, or 2.5 g / cm 3 or less. A gas pycnometer is a device for measuring the true density of powders, solids, and slurries. A description of the specific measurement method is provided below.

[0101] In the solid electrolyte according to the embodiment, the ionic conductivity of the solid ion conductor at 25 °C may be about 3.4 x 10 -6 Siemens / cm (S cm -1 ) to about 5.0 x 10 -6 S cm -1 , about 3.4 x 10 -6 S cm -1 to about 4.9 x 10 - 6 S cm -1 , about 3.4 x 10 -6 S cm -1 to about 4.8 x 10 -6 S cm -1 , about 3.4 x 10 -6 S cm -1 to about 4.7 x 10 -6 S cm -1 , about 3.4 x 10 -6 S cm -1 to about 4.6 x 10 -6 S cm -1 , about 3.4 x 10 -6 S cm -1 to about 4.5 x 10 -6 S cm -1 , or about 3.4 x 10 -6 S cm -1 to about 4.4 x 10 -6 S cm -1 .

[0102] The solid electrolyte according to an embodiment may further include a composite solid ion conductor, and the composite solid ion conductor further includes a crystalline solid ion conductor represented by Formula 2:

[0103] Formula 2

[0104] Li a1 B b1 Al m1 O c1 X d1

[0105] Wherein, in Formula 2, X may be at least one of F, Cl, Br, or I, 3.5 ≤ a1 ≤ 4.5, 3 ≤ b1 ≤ 5.2, 1 ≤ m1 ≤ 3, 11 ≤ c1 ≤ 13, and 0 ≤ d1 ≤ 1.5.

[0106] By further including the crystalline solid ion conductor represented by Formula 2, the solid electrolyte according to an embodiment may include a composite solid ion conductor, and the composite solid ion conductor includes a solid ion conductor represented by Formula 1 having a glassy or amorphous structure at room temperature (25 °C) and a solid ion conductor represented by Formula 2 having a crystalline structure, thereby improving the adhesion between the solid electrolyte and the electrode active material. In addition, the solid electrolyte including such a composite solid ion conductor may have a smaller pore size after the secondary heat treatment to be described later, and thus, may have a further improved ionic conductivity.

[0107] In the solid electrolyte according to an embodiment, the volume ratio of the solid ion conductor represented by Formula 1 to the solid ion conductor represented by Formula 2 in the composite solid ion conductor may be from about 97:3 to about 50:50. When the volume ratio of the solid ion conductor represented by Formula 1 to the solid ion conductor represented by Formula 2 is within the above range, the solid electrolyte including it may have a smaller pore size after the heat treatment to be described later, thereby maximizing the ionic conductivity.

[0108] The solid electrolyte according to an embodiment may have a thickness of about 0.1 micrometers (μm) to about 30 μm. The thickness of the solid electrolyte may be appropriately adjusted to meet the desired density and desired ionic conductivity within the above range.

[0109] Method for manufacturing a solid electrolyte

[0110] The method for manufacturing a solid electrolyte according to a further embodiment includes: mechanically grinding a lithium source, a boron source, an aluminum source, a Q element source, and a halogen source to provide a glassy solid ion conductor; and heat-treating the glassy solid ion conductor at a temperature equal to or higher than the initial thermal decomposition temperature (Ts) measured by differential scanning calorimetry (DSC) to provide a crystalline-containing solid ion conductor represented by Formula 1

[0111] Formula 1

[0112] Li a B b Al m Q n O c X d

[0113] Wherein, in Formula 1, Q can be an element having an ionic radius differing from that of Al by less than 30% and having +3 and +5 valence states (or having a +3 valence state), X can be at least one of F, Cl, Br, or I, 3.5 ≤ a ≤ 4.5, 3 ≤ b < 5.2, 1 ≤ m ≤ 3, 0 < n < 2, 11 ≤ c ≤ 13, and 0 < d ≤ 1.5.

[0114] The solid electrolyte manufactured by the method for manufacturing a solid electrolyte can achieve high density and high ionic conductivity at a low sintering temperature.

[0115] First, a ground mixture can be prepared by mechanically grinding a lithium source, a boron source, an aluminum source, a Q element source, and a halogen source. The lithium source, the boron source, the aluminum source, the Q element source, and the halogen source can each include chlorides, halides, oxides, nitrides, oxynitrides, nitrates, hydroxides, and carbonates of lithium, boron, aluminum, or the Q element. Examples of the lithium source include Li2CO3, LiOH, etc. Examples of the boron source include B2O3, etc. Examples of the aluminum source can include Al2O3, Al(OH)3, etc. The Q element source can be at least one of, for example, an Sb source or a V source. Examples of the Sb source include Sb2O3, Sb2O5, SbF3, SbF5, SbCl3, SbCl5, SbCl2F3, SbCl3F2, Sb(NO3)3, Sb(OH)3, Sb(OH)5, etc. Examples of the V source include V2O3, V2O5, etc. Examples of the halogen source include LiCl, etc. The lithium source, the boron source, the aluminum source, the Q element source, and the halogen source can be added to a reactor in stoichiometric proportions according to the composition of the solid ion conductor to be obtained, and then they can be mechanically ground. Mechanical ball milling can be carried out by methods such as ball milling, high-energy ball milling, mechanofusion grinding, etc. For example, high-energy ball milling can be carried out dry in an inert atmosphere for about 0.5 hours to about 1,000 hours, about 0.5 hours to about 100 hours, or about 10 hours to about 30 hours. For example, high-energy ball milling can be carried out dry in an inert atmosphere at a speed of about 300 revolutions per minute (rpm) to about 10,000 rpm, about 350 rpm to about 5,000 rpm, or about 370 rpm to about 1,000 rpm. High-energy ball milling can be carried out for about 0.5 hours to about 150 hours, about 1 hour to about 100 hours, or about 3 hours to about 50 hours. During such high-energy ball milling, the temperature can rise to 200 °C during ball milling, and the pressure during ball milling can be on the order of 6 gigapascals (GPa) (about 6 GPa). For example, PULVERISETTE 7 premium line can be used. The particle diameter of the mixture ground by mechanical grinding can be, for example, about 0.1 μm to about 10 μm, or about 0.1 μm to about 5 μm.

[0116] Next, the ground mixture can be preheated at a temperature of about 600 °C to about 1,300 °C for about 1 hour to about 36 hours, and then quenched to prepare a vitreous solid ion conductor. For example, the temperature for preheating can be 650 °C or higher, 700 °C or higher, 750 °C or higher, 1,250 °C or lower, 1,200 °C or lower, or 1,150 °C or lower. For example, the duration of preheating can be about 2 hours to about 30 hours, or about 3 hours to about 20 hours. The preheating can be carried out by adding the ground mixture to a pot and heat-treating it at a heating rate of about 1 degree Celsius per minute (°C / min) to about 20 °C / min or about 5 °C / min to about 15 °C / min. Alternatively, the ground mixture can be added to an induction heating stirrer and heat-treated at a high frequency such as 1 kilowatt (kW) to 5 kW until it turns into a different color. After that, the melt can be dropped between two rollers and quenched to a temperature of 200 °C or lower within a cooling time of 1 second to produce a vitreous solid ion conductor. Here, printing of the vitreous solid ion conductor can be carried out by using a screen printing method or the like.

[0117] Next, a crystalline-containing solid ion conductor represented by Formula 1 can be prepared by heat-treating the vitreous solid ion conductor at a temperature equal to or higher than the initial thermal decomposition temperature (T s ) measured by differential scanning calorimetry:

[0118] Formula 1

[0119] Li a B b Al m Q n O c X d

[0120] wherein, in Formula 1, Q can be an element having an ionic radius differing from that of Al by less than 30% and having +3 and +5 valence states (or having a +3 valence state), X can be at least one of F, Cl, Br, or I, 3.5 ≤ a ≤ 4.5, 3 ≤ b < 5.2, 1 ≤ m ≤ 3, 0 < n < 2, 11 ≤ c ≤ 13, and 0 < d ≤ 1.5.

[0121] The initial thermal decomposition temperature T s can be, for example, about 500 °C to about 530 °C. The production of the crystalline-containing solid ion conductor can include heat-treating the vitreous solid ion conductor in an air atmosphere, or setting insulating films on both sides of the vitreous solid ion conductor and then performing heat treatment.

[0122] For example, in a method of manufacturing a solid ion conductor, the glassy solid ion conductor can be heat-treated at a temperature of 600 °C or lower for about 5 minutes to about 2 hours. The temperature at which the heat treatment is carried out can be, for example, 400 °C or higher, 450 °C or higher, 500 °C or higher, 570 °C or lower, or 550 °C or lower. In the manufacture of the crystalline solid ion conductor, an insulating film can be disposed on both sides of the glassy solid ion conductor, and it can be heat-treated at a pressure of about 1 MPa to about 50 MPa and a temperature of about 400 °C to about 600 °C. The insulating film can use a blocking electrode such as a spacer. The heat treatment using the insulating film can eliminate the surface resistance when crystallizing the glassy solid ion conductor, and can produce a ceramic solid ion conductor containing dense crystals. The resulting crystalline solid ion conductor can have a higher ionic conductivity.

[0123] Lithium battery

[0124] A lithium battery according to a further aspect may include a positive electrode, a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode, wherein at least one of the positive electrode, the negative electrode, or the solid electrolyte layer includes the solid electrolyte.

[0125] The lithium battery according to an embodiment may be a lithium ion battery, an all-solid-state battery, or a multilayer ceramic (MLC) battery.

[0126] Lithium ion battery

[0127] For example, a lithium ion battery may include a positive electrode, a negative electrode, and a liquid electrolyte disposed between the positive electrode and the negative electrode, wherein a protective layer including a solid ion conductor represented by Formula 1 can be disposed on one side of at least one of the positive electrode and the negative electrode.

[0128] For example, a lithium ion battery may include a positive electrode active material layer, and the positive electrode active material layer may include a composite positive electrode active material, the composite positive electrode active material including: a core including a positive electrode active material; and a first coating layer disposed on the core, wherein the first coating layer may include a solid ion conductor represented by Formula 1.

[0129] For example, a lithium ion battery may include a negative electrode active material layer, and the negative electrode active material layer may include a composite negative electrode active material, the composite negative electrode active material including: a core including a negative electrode active material; and a second coating layer disposed on the core, wherein the second coating layer may include a solid ion conductor represented by Formula 1.

[0130] For example, a lithium ion battery can be manufactured as follows.

[0131] First, a positive electrode can be prepared. A positive electrode active material, a conductive material, a binder, and a solvent can be mixed to prepare a composition for forming a positive electrode active material layer. In an embodiment, the composition for forming the positive electrode active material layer can be directly applied onto a positive electrode current collector and dried to prepare the positive electrode. In one or more embodiments, the composition for forming the positive electrode active material layer can be cast onto a separate carrier, and then the film obtained by peeling from the carrier can be laminated onto the positive electrode current collector to prepare the positive electrode. In one or more embodiments, the composition for forming the positive electrode active material layer can be prepared in the form of electrode ink containing an excessive amount of solvent, and the electrode ink can be printed onto the carrier by an inkjet method or a gravure printing method to prepare the positive electrode. The printing method is not limited to the above methods, and any method that can be used for general coating and printing can be used.

[0132] On one surface of the positive electrode active material layer included in the positive electrode, a solid electrolyte including a solid ion conductor represented by Formula 1 can be applied to form a positive electrode protective layer. Alternatively, solid electrolyte particles containing a solid ion conductor represented by Formula 1 can be added to the composition for forming the positive electrode active material layer, and thus can be included in the positive electrode active material layer.

[0133] The positive electrode current collector can include a metal substrate. For use as the metal substrate, for example, a plate or foil formed of aluminum (Al), indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), germanium (Ge), lithium (Li), or an alloy thereof can be used. The positive electrode current collector can be omitted. The positive electrode current collector can further include a carbon layer disposed on one or both sides of the metal substrate. When the carbon layer is additionally disposed on the metal substrate, the metal of the metal substrate can be prevented from being corroded by the solid electrolyte included in the positive electrode, and the interfacial resistance between the positive electrode active material layer and the positive electrode current collector can be reduced. The thickness of the carbon layer can be, for example, about 0.1 μm to about 5 μm, about 0.1 μm to about 3 μm, or about 0.1 μm to about 1 μm. When the carbon layer is too thin, the contact between the metal substrate and the solid electrolyte may not be completely blocked. When the carbon layer is too thick, the energy density of the lithium ion battery may be reduced. The carbon layer can include amorphous carbon, crystalline carbon, etc.

[0134] For use as the positive electrode active material, any material commonly used in lithium batteries in the art can be used without limitation. For example, lithium transition metal oxides, transition metal sulfides, etc. can be used. For example, the positive electrode active material can include at least one composite oxide of lithium and a metal selected from cobalt, manganese, nickel, or a combination thereof, and examples thereof can include compounds represented by at least one of the following formulas: Li a A' 1-b B' bD'2 (where 0.90 ≤ a ≤ 1.8 and 0 ≤ b ≤ 0.5); Li a E' 1-b B' b O 2-c D' c (where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, and c ≤ 0.05); LiE' 2-b B' b O 4-c D' c (where 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b B' c D' α (where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, and 0 < α ≤ 2); Li a Ni 1-b-c Co b B' c O 2-α F' α (where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, and 0 < α < 2); Li a Ni 1-b- c Co b B' c O 2-α F'2 (where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, and 0 < α < 2); Li a Ni 1-b-c Mn b B' c D' α (where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, and 0 < α ≤ 2); Li a Ni 1-b-c Mn b B' c O 2-α F' α (where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, and 0 < α < 2); Li a Ni 1-b-c Mn b B' c O 2-α F'2 (where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, and 0 < α < 2); Li a Ni b E' c G' dO2 (where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, and 0.001 ≤ d ≤ 0.1); Li a Ni b Co c Mn d G' e O2 (where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, and 0.001 ≤ e ≤ 0.1); Li a NiG' b O2 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a CoG' b O2 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a MnG' b O2 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a Mn2G' b O4 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Q'O2; Q'S2; LiQ'S2; V2O5; LiV2O2; LiI'O2; LiNiVO4; Li (3-f) J'2(PO4)3 (where 0 ≤ f ≤ 2); Li (3-f) Fe2(PO4)3 (where 0 ≤ f ≤ 2); or LiFePO4. In the above formula, A' can be Ni, Co, Mn, or a combination thereof; B' can be Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, or a combination thereof; D' can be O, F, S, P, or a combination thereof; E' can be Co, Mn, or a combination thereof; F' can be F, S, P, or a combination thereof; G' can be Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q' can be Ti, Mo, Mn, or a combination thereof; I' can be Cr, V, Fe, Sc, Y, or a combination thereof; and J' can be V, Cr, Mn, Co, Ni, Cu, or a combination thereof. For example, the positive electrode active material can be LiCoO2, LiMn x O 2x (where x is 1 and 2), LiNi 1-x Mn x O2 (where 0 < x < 1), LiNi 1-x-y Co x Mn y O2 (where 0 ≤ x ≤ 0.5 and 0 ≤ y ≤ 0.5), LiFePO4, TiS2, FeS2, TiS3, FeS3, etc. The conductive composition can be applied on the surface of the positive electrode active material to inhibit side reactions between the positive electrode active material and the electrolyte solution.

[0135] The conductive material may include, for example, carbon black, carbon fiber, graphite, or a combination thereof. The carbon black may be, for example, acetylene black, Ketjen black, Super P carbon (superconductive carbon black), channel black, furnace black, lamp black, thermal carbon black, or a combination thereof. The graphite may be natural graphite or artificial graphite. A combination of at least two of the above materials may be used. In addition to such carbonaceous conductive materials, the positive electrode may further include additional conductive materials. Such additional conductive materials may include: conductive fibers such as metal fibers; carbon fluoride powder; metal powders such as aluminum powder or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; or polyethylene derivatives. A combination of at least two of the above-mentioned additional conductive materials may be used. Based on 100 parts by weight of the positive electrode active material, the amount of the conductive material may be about 1 part by weight to about 10 parts by weight, for example, about 2 parts by weight to about 7 parts by weight. When the amount of the conductive material is within the above range, for example, about 1 part by weight to about 10 parts by weight, the positive electrode may have appropriate conductivity.

[0136] The binder can improve the adhesion between the components of the positive electrode and between the positive electrode and the current collector of the positive electrode. Examples of the binder include polyacrylic acid (PAA), polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene propylene diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, copolymers thereof, or combinations thereof. Based on 100 parts by weight of the positive electrode active material, the amount of the binder may be about 1 part by weight to about 10 parts by weight, for example, about 2 parts by weight to about 7 parts by weight. When the amount of the binder is within the above range, the adhesion of the positive electrode active material layer to the positive electrode current collector can be further improved, and a decrease in the energy density of the positive electrode active material layer can be suppressed.

[0137] For use as a solvent, N-methylpyrrolidone, acetone, water, etc. may be used. The amounts of the positive electrode active material, the conductive material, the binder, and the solvent may be at levels suitable for use in a lithium battery.

[0138] A plasticizer may be added to the positive electrode active material composition to form pores in the positive electrode active material layer.

[0139] Next, the negative electrode can be prepared. The negative electrode active material, conductive material, binder, and solvent can be mixed to prepare a composition for forming a negative electrode active material layer. In an embodiment, the composition for forming the negative electrode active material can be directly applied onto a copper current collector and dried to prepare the negative electrode. In one or more embodiments, the composition for forming the negative electrode active material can be cast onto a separate carrier, and then the negative electrode active material film obtained by peeling from the carrier can be laminated onto the copper current collector to prepare the negative electrode. In one or more embodiments, the composition for forming the negative electrode active material layer can be prepared in the form of an electrode ink containing an excessive amount of solvent, and the electrode ink can be printed onto the carrier by an inkjet method or a gravure printing method to prepare the negative electrode. The printing method is not limited to the above methods, and any method that can be used for ordinary coating and printing can be used.

[0140] For example, the negative electrode active material can include at least one of lithium metal, lithium metal alloy, a metal capable of alloying with lithium, transition metal oxide, non-transition metal oxide, or carbon-containing material. The lithium metal alloy refers to an alloy of lithium and other metals such as indium. Examples of the metal capable of alloying with lithium include Si, Sn, Al, Ge, Pb, Bi, Sb, Si-Y' alloy (where Y' is an alkali metal, alkaline earth metal, group 13 element, group 14 element, group 15 element, group 16 element, transition metal, rare earth element, or a combination thereof, but not Si), Sn-Y' alloy (where Y' is an alkali metal, alkaline earth metal, group 13 element, group 14 element, group 15 element, group 16 element, transition metal, rare earth element, or a combination thereof, but not Sn), etc. The element Y' can be, for example, Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof. The transition metal oxide can include, for example, lithium titanium oxide, vanadium oxide, lithium vanadium oxide, etc. The non-transition metal oxide can include, for example, SnO2, SiO x (where 0 < x < 2), etc. The carbon-containing material can include, for example, crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon can be graphite, such as natural graphite or artificial graphite, which is in an unshaped form or in the form of plates, flakes, spheres, or fibers. The amorphous carbon can include soft carbon (low-temperature calcined carbon), hard carbon, mesophase pitch carbide, calcined coke, etc. For example, the negative electrode active material can include lithium metal, lithium metal alloy, or a combination thereof.

[0141] The conductive material, binder, and solvent for manufacturing the negative electrode can be selected from the materials for manufacturing the positive electrode in the form of a plate. The amounts of the negative electrode active material, the conductive material, the binder, and the solvent can be at levels commonly used in lithium batteries.

[0142] A plasticizer can be added to the composition for forming the negative electrode active material to form pores in the negative electrode active material layer.

[0143] A protective layer including a solid electrolyte comprising a solid ion conductor represented by Formula 1 can be disposed on one side of the negative electrode active material layer. In one or more embodiments, the negative electrode active material can include negative electrode active material particles, the negative electrode active material particles including: a core including lithium metal, a lithium metal alloy, or a combination thereof; and a first coating layer disposed on the core, wherein the first coating layer can include a solid electrolyte including a solid ion conductor represented by Formula 1. When such a protective layer and / or coating layer is disposed on the negative electrode, the lithium ion conductivity and / or the stability against lithium metal of the negative electrode can be improved. Alternatively, solid electrolyte particles containing a solid ion conductor represented by Formula 1 can be added to the composition for forming the negative electrode active material layer and can thus be included in the negative electrode active material layer.

[0144] Next, a separator can be prepared.

[0145] The positive electrode and the negative electrode can be separated by a separator, and any separator commonly used in the art for lithium batteries can be used. A separator having low resistance to ion movement in the electrolyte and excellent electrolyte wettability can be suitable. For example, the separator can be a material selected from glass fiber, polyester, Teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), or a combination thereof, and can be in any form of a non-woven fabric or a woven fabric. More specifically, a wound separator including polyethylene, polypropylene, etc. can be used for a lithium ion battery, and a separator having excellent impregnation of an organic electrolyte solution can be used for a lithium ion polymer battery.

[0146] The separator can be manufactured as follows. A polymer resin, a filler, and a solvent can be mixed to prepare a separator composition. In an embodiment, the separator composition can be directly applied onto an electrode and dried to form a separator film. In one or more embodiments, the separator composition can be cast onto a separate carrier and dried. The separator film obtained by peeling from the carrier can then be laminated onto the electrode to form the separator. The polymer resin is not particularly limited, and any material that can be used as an adhesive for an electrode plate can be used. For example, a vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, or a mixture thereof can be used as the polymer resin. For example, a vinylidene fluoride / hexafluoropropylene copolymer including hexafluoropropylene in an amount of about 8 weight percent (wt%) to about 25 wt% can be suitable.

[0147] The separator can further include a solid electrolyte including a solid ion conductor represented by Formula 1. For example, a coating including a solid electrolyte including a solid ion conductor represented by Formula 1 can be added on at least one side of the separator. When the separator further includes the coating, the heat resistance and dimensional stability of the separator can be further improved. For example, the separator can include: a porous substrate; and a coating disposed on one or both sides of the porous substrate, wherein the coating can include a solid electrolyte including a solid ion conductor represented by Formula 1.

[0148] Next, a liquid electrolyte can be prepared.

[0149] The liquid electrolyte can be an organic electrolyte solution containing an organic solvent. The organic electrolyte solution can be prepared by dissolving a lithium salt in an organic solvent. Any organic solvent available in the art can be used as the organic solvent. Any lithium salt available in the art can be used as the lithium salt. The amount of the lithium salt can be about 0.1 mole per liter (M) to about 10 M, or about 0.1 M to about 5 M, but is not limited thereto. The amount can be appropriately changed within a range that can provide improved battery performance. The liquid electrolyte can further include, for example, a flame retardant, such as a phosphorus-based flame retardant or a halogen-based flame retardant.

[0150] In a lithium ion battery according to one embodiment, the positive electrode, the negative electrode, and the separator can be wound or folded to form a battery structure. The formed battery structure can be accommodated in a battery case. The lithium ion battery can include electrode tabs that serve as a circuit path for guiding the current formed in the battery structure to the outside. A composition for forming an electrolyte can be injected into the battery case and crosslinked, or a solid electrolyte can be disposed, and then the battery case can be sealed to complete the manufacture of the lithium ion battery. The battery case is not limited and can be, for example, a cylindrical type, a square type, a thin film type, etc.

[0151] A lithium-ion battery according to another embodiment may be a pouch-type lithium-ion battery that uses a pouch as a case of the lithium-ion battery. The pouch-type lithium-ion battery may include at least one battery structure. A separator may be disposed between a positive electrode and a negative electrode to form the battery structure. A plurality of battery structures may be stacked in a thickness direction, impregnated with an organic electrolyte solution, accommodated in a pouch, and then sealed to complete the manufacture of the pouch-type lithium battery. For example, although not shown in the drawings, the positive electrode, the negative electrode, and the separator may be simply stacked in the form of an electrode assembly and accommodated in a pouch, or may be wound or folded into an electrode assembly in the form of a jelly roll and then accommodated in a pouch. Subsequently, a composition for forming an electrolyte may be injected into the pouch and crosslinked, or a solid electrolyte may be disposed, and then the pouch may be sealed to complete the manufacture of the lithium-ion battery.

[0152] The lithium-ion battery may have excellent characteristics in terms of discharge capacity and life and a high energy density, and thus may be used, for example, in electric vehicles (EVs). For example, a lithium metal battery may be used in hybrid vehicles, such as plug-in hybrid electric vehicles (PHEVs), etc. The lithium metal battery may also be applied to fields that require high-power storage. For example, the lithium-ion battery may be used in electric bicycles, power tools, etc.

[0153] A plurality of lithium-ion batteries may be stacked to form a battery module, and a plurality of battery modules may form a battery pack. The battery pack may be used in devices that require high capacity and large output. For example, the battery pack may be used in laptop computers, smart phones, electric vehicles, etc. The battery module may include, for example, a plurality of batteries and a frame that holds the plurality of batteries. For example, the battery pack may include a plurality of battery modules and a bus bar that connects the battery modules together. The battery module and / or the battery pack may further include a cooling device. The plurality of battery packs may be managed by a battery management system. The battery management system may include a battery pack and an electronic control device connected to the battery pack.

[0154] All-solid-state battery

[0155] An all-solid-state battery may be a battery that includes a solid electrolyte. An all-solid-state battery according to an embodiment may include a solid electrolyte that includes a solid ion conductor represented by Formula 1.

[0156] The all-solid-state battery may include: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and a solid electrolyte disposed between the positive electrode and the negative electrode, wherein at least one of the positive electrode or the negative electrode may include a solid electrolyte including a solid ion conductor represented by Formula 1. For example, the all-solid-state battery may include a positive electrode active material layer, and the positive electrode active material layer may include a solid electrolyte including a solid ion conductor represented by Formula 1. For example, the all-solid-state battery may include a negative electrode active material layer, and the negative electrode active material layer may include a solid electrolyte including a solid ion conductor represented by Formula 1. The all-solid-state battery may include a solid electrolyte disposed between the positive electrode and the negative electrode, and the solid electrolyte may include an electrolyte represented by Formula 1. For example, the all-solid-state battery may include a positive electrode active material layer, and the positive electrode active material layer may include a composite positive electrode active material including: a core including a positive electrode active material; and a first coating layer disposed on the core, wherein the first coating layer may include a solid ion conductor represented by Formula 1. For example, the all-solid-state battery may include a negative electrode active material layer, and the negative electrode active material layer may include a composite negative electrode active material including: a core including a negative electrode active material; and a second coating layer disposed on the core, wherein the second coating layer may include a solid ion conductor represented by Formula 1.

[0157] The all-solid-state battery may be an all-solid-state battery using a non-precipitating (non-depositing) negative electrode or an all-solid-state battery using a precipitating (depositing) negative electrode.

[0158] In the all-solid-state battery using a non-precipitating negative electrode, the initial charge capacity of the negative electrode active material layer during the initial charging may be, for example, greater than 50%, 60% or more, 70% or more, 80% or more, 90% or more, or 100% or more of the initial charge capacity of the positive electrode active material layer. In the all-solid-state battery using a precipitating negative electrode, the initial charge capacity of the negative electrode active material layer during the initial charging may be, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, 5% or less, or 1% or less of the initial charge capacity of the positive electrode active material layer.

[0159] The all-solid-state battery using a non-precipitating negative electrode may be prepared as follows.

[0160] First, a solid electrolyte can be prepared. For example, the solid electrolyte can be prepared by: mixing a solid electrolyte including a solid ion conductor represented by Formula 1 and a binder and drying the mixture, or pressing a solid electrolyte powder containing a solid ion conductor represented by Formula 1 into a certain shape. For example, the solid electrolyte can be prepared by: mixing a solid electrolyte including a solid ion conductor represented by Formula 1, a sulfide and / or oxide solid electrolyte, and a binder and drying the mixture, or pressing a solid electrolyte powder containing a solid ion conductor represented by Formula 1 and a sulfide solid electrolyte powder and / or an oxide solid electrolyte powder into a certain shape. For example, the solid electrolyte can be prepared by: mixing a sulfide solid electrolyte and / or an oxide solid electrolyte with a binder and drying the mixture, or pressing a sulfide solid electrolyte powder and / or an oxide solid electrolyte powder into a certain shape.

[0161] For example, the solid electrolyte can be deposited by using a film-forming method such as blasting, aerosol deposition, cold spraying, sputtering, chemical vapor deposition (CVD), spraying, etc., and thereby a solid electrolyte layer can be prepared. In addition, the solid electrolyte layer can be formed by pressing. In addition, the solid electrolyte layer can be prepared by: mixing a solid electrolyte, a solvent, and a binder or a carrier and pressing the mixture. In this case, a solvent or a carrier can be added to enhance the strength of the solid electrolyte or prevent short-circuiting of the solid electrolyte.

[0162] For example, the binder included in the solid electrolyte layer can include styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polyvinyl alcohol, etc., but is not limited thereto. Any material that can be used as a binder in the art can be used. The binder of the solid electrolyte can be the same as or different from the binders of the negative electrode and the positive electrode.

[0163] In addition to the solid electrolyte including a solid ion conductor represented by Formula 1, the solid electrolyte can further include an oxide solid electrolyte. The oxide solid electrolyte can include at least one selected from the following: Li 1+x+y Al x Ti 2- x Si y P 3-y O 12 (where 0 < x < 2 and 0 ≤ y < 3), BaTiO3, Pb(Zr a Ti 1-a )O3 (PZT, where 0 ≤ a ≤ 1), Pb 1-x La x Zr 1- y Ti yO3(PLZT) (where 0 ≤ x < 1 and 0 ≤ y < 1), Pb(Mg 1 / 3 Nb 2 / 3 )O3 - PbTiO3 (PMN - PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, Li3PO4, Li x Ti y (PO4)3 (where 0 < x < 2 and 0 < y < 3), Li x Al y Ti z (PO4)3 (where 0 < x < 2, 0 < y < 1, and 0 < z < 3), Li 1+x+y (Al a Ga 1-a ) x (Ti b Ge 1-b ) 2- x Si y P 3-y O 12 (where 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ a ≤ 1, and 0 ≤ b ≤ 1), Li x La y TiO3 (where 0 < x < 2 and 0 < y < 3), Li2O, LiOH, Li2CO3, LiAlO2, Li2O - Al2O3 - SiO2 - P2O5 - TiO2 - GeO2, Li 3+x La3M2O 12 (where M is Te, Nb or Zr, and x is an integer from 1 to 10).

[0164] In addition to the solid electrolyte including the solid ion conductor represented by Formula 1, the solid electrolyte may further include a sulfide solid electrolyte.

[0165] Non - limiting examples of the sulfide solid electrolyte material include Li2S - P2S5; Li2S - P2S5 - LiX (where X is a halogen element, such as F, Cl, Br or I); 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 each positive numbers, and Z is Ge, Zn, or Ga); Li2S-GeS2; Li2S-SiS2-Li3PO4; and Li2S-SiS2-Li p MO q (where p and q are each positive numbers, and M is P, Si, Ge, B, Al, Ga, or In). The sulfide solid electrolyte material can be prepared by treating starting materials (e.g., Li2S, P2S5, etc.) of the sulfide solid electrolyte material via a melt quenching method, a mechanical grinding method, etc. In addition, a calcination process can be carried out after the treatment.

[0166] Alternatively, an example of the sulfide solid electrolyte can be a compound having an argyrodite crystal structure. The compound having an argyrodite crystal structure can include Li 7-x PS 6-x Cl x (where 0 < x < 2), Li 7-x PS 6-x Br x (where 0 < x < 2), or Li 7-x PS 6-x I x (where 0 < x < 2) of at least one. The sulfide solid electrolyte included in the solid electrolyte can be an argyrodite-type compound including at least one of Li6PS5Cl, Li6PS5Br, or Li6PS5I. As used herein, argyrodite is a silver germanium sulfide mineral, which can be referred to using the formula Ag8GeS6. As used herein, the term "argyrodite compound" means that the compound is isostructural with argyrodite. In the present disclosure, the term "isostructural" refers to the crystal structure of the compound. The crystal structures are the same, but the unit cell dimensions and / or chemical compositions are not the same.

[0167] Next, a positive electrode can be prepared.

[0168] A positive electrode active material layer including a positive electrode active material can be formed on a positive electrode current collector to prepare the positive electrode. The positive electrode active material layer can be prepared by a gas phase method or a solid phase method. The gas phase method can include pulsed laser deposition (PLD), sputter deposition, chemical vapor deposition (CVD), etc., but is not limited thereto. Any method available in the art can be used. Alternatively, the positive electrode active material layer can be prepared by a sintering method, a sol-gel method, a doctor blade method, a screen printing method, a slurry casting method, a powder pressing method, etc., but is not necessarily limited thereto. Any method available in the art can be used.

[0169] The positive electrode active material layer can include a positive electrode active material. The positive electrode active material and the positive electrode current collector can be selected from the materials used in the above lithium ion battery.

[0170] The positive electrode active material layer may additionally include a binder, a conductive material, etc. The binder and the conductive material may be selected from the materials used in the above lithium ion battery.

[0171] The positive electrode active material layer may further include a solid electrolyte including a solid ion conductor represented by Formula 1. Based on the total volume of the positive electrode active material layer, the amount of the solid electrolyte in the positive electrode active material layer may be about 5 parts by volume to about 50 parts by volume, about 5 parts by volume to about 40 parts by volume, or about 10 parts by volume to about 35 parts by volume. A protective layer including a solid electrolyte including a solid ion conductor represented by Formula 1 may be disposed on the positive electrode active material layer.

[0172] Next, a negative electrode may be prepared.

[0173] The negative electrode may be prepared in the same manner as the positive electrode, except that: a negative electrode active material is used instead of the positive electrode active material. A negative electrode active material layer including a negative electrode active material may be formed on a negative electrode current collector to prepare the negative electrode.

[0174] The negative electrode active material layer may include a negative electrode active material. The negative electrode active material may be selected from the materials used in the above lithium ion battery. For example, the negative electrode active material may include lithium metal, a lithium metal alloy, or a combination thereof.

[0175] The negative electrode active material layer may additionally include a binder, a conductive material, etc. The binder and the conductive material may be selected from the materials used in the above lithium ion battery.

[0176] The negative electrode active material layer may further include a solid electrolyte including a solid ion conductor represented by Formula 1. A protective layer including a solid electrolyte including a solid ion conductor represented by Formula 1 may be disposed on the negative electrode active material layer.

[0177] For example, the all-solid-state battery may include the solid electrolyte, a positive electrode disposed on one side of the solid electrolyte, and a negative electrode disposed on the other side of the solid electrolyte. The positive electrode may include a positive electrode active material layer in contact with the solid electrolyte and a positive electrode current collector in contact with the positive electrode active material layer, and the negative electrode may include a negative electrode active material layer in contact with the solid electrolyte and a negative electrode current collector in contact with the negative electrode active material layer. For example, in the all-solid-state battery, the positive electrode active material layer and the negative electrode active material layer may be formed on both sides of the solid electrolyte, and the positive electrode current collector and the negative electrode current collector may be formed on the positive electrode active material layer and the negative electrode active material layer, respectively, thereby completing the manufacture of the all-solid-state battery. Alternatively, in the all-solid-state battery, the negative electrode active material layer, the solid electrolyte, the positive electrode active material layer, and the positive electrode current collector may be sequentially deposited on the negative electrode current collector, thereby completing the manufacture of the all-solid-state battery.

[0178] The all-solid-state battery using a precipitation negative electrode can be manufactured in the same manner as the all-solid-state battery using a non-precipitation negative electrode, except for the negative electrode.

[0179] The negative electrode can be prepared as follows.

[0180] The negative electrode may include a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector, and the negative electrode active material layer may include, for example, a negative electrode active material and a binder.

[0181] For example, the negative electrode active material may be in the form of particles. The average particle diameter of the negative electrode active material in the form of particles may be, for example, 4 μm or less, 3 μm or less, 2 μm or less, 1 μm or less, or 900 nm or less. The average particle diameter of the negative electrode active material in the form of particles may be, for example, about 10 nm to about 4 μm, about 10 nm to about 3 μm, about 10 nm to about 2 μm, about 10 nm to about 1 μm, or about 10 nm to about 900 nm. When the average particle diameter of the negative electrode active material is within the above range, lithium can more easily undergo reversible absorption and / or desorption during charging and discharging. The average particle diameter of the negative electrode active material may be, for example, the median diameter (D50) measured by using a laser particle size distribution analyzer.

[0182] For example, the negative electrode active material may include at least one of a carbon-containing negative electrode active material and a metal or metalloid negative electrode active material.

[0183] For example, the carbon-containing negative electrode active material may be amorphous carbon. For example, the amorphous carbon may include carbon black (CB), acetylene black (AB), furnace black (FB), Ketjen black (KB), graphene, etc., but is not limited thereto. Any material classified as amorphous carbon in the art may be used. The amorphous carbon may be carbon that does not have crystallinity or has very low crystallinity, and in this regard, it can be distinguished from crystalline carbon or graphite-based carbon.

[0184] For example, the metal or metalloid negative electrode active material may include at least one of Au, Pt, Pd, Si, Ag, Al, Bi, Sn, or Zn, but is not limited thereto. Any material that can be used as a metal or metalloid negative electrode active material capable of forming an alloy or compound with lithium in the art may be used. For example, since nickel (Ni) does not form an alloy with lithium, Ni may not be a metal negative electrode active material.

[0185] In such a negative electrode active material, the negative electrode active material layer may include a single negative electrode active material, or may include a mixture of a plurality of different negative electrode active materials. In an embodiment, the negative electrode active material layer may include only amorphous carbon, or may include at least one of Au, Pt, Pd, Si, Ag, Al, Bi, Sn, or Zn.

[0186] Alternatively, the negative electrode active material layer may include a mixture of at least one of Au, Pt, Pd, Si, Ag, Al, Bi, Sn, or Zn and amorphous carbon. The mixing weight ratio of amorphous carbon to the mixture of metals, etc. may be, for example, about 10:1 to about 1:2, about 5:1 to about 1:1, or about 4:1 to about 2:1, but is not limited thereto. The mixing weight ratio may be determined according to the characteristics of the all-solid-state battery. When the negative electrode active material has such a composition, the cycle characteristics of the all-solid-state battery can be further improved.

[0187] For example, the negative electrode active material may include a mixture of first particles of amorphous carbon and second particles of a metal or metalloid. For example, the metal or metalloid may include Au, Pt, Pd, Si, Ag, Al, Bi, Sn, Zn, etc. The metalloid may be, for example, a semiconductor. Based on the total weight of the mixture, the amount of the second particles may be about 8 wt% to about 60 wt%, about 10 wt% to about 50 wt%, about 15 wt% to about 40 wt%, or about 20 wt% to about 30 wt%. When the amount of the second particles is within the above range, the cycle characteristics of the all-solid-state battery can be further improved.

[0188] The binder may include, for example, SBR, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., but is not limited thereto. Any material available in the art as a binder can be used. The binder can be used alone or in combination of a plurality of different binders.

[0189] When the negative electrode active material layer includes the binder, the negative electrode active material layer can be stabilized on the negative electrode current collector. In addition, although there are changes in the volume and / or relative position of the negative electrode active material layer during charging and discharging, breakage of the negative electrode active material layer can be suppressed. For example, when the negative electrode active material layer does not include the binder, the negative electrode active material layer can be easily separated from the negative electrode current collector. In a region where the negative electrode current collector is exposed due to the separation of the negative electrode active material layer from the negative electrode current collector, the negative electrode current collector can come into contact with the solid electrolyte, thereby increasing the possibility of short circuit. The negative electrode active material layer can be prepared, for example, by coating the negative electrode current collector with a slurry in which the materials constituting the negative electrode active material layer are dispersed, and then drying the coated negative electrode active material layer. When the negative electrode active material layer includes the binder, the negative electrode active material layer can be stably dispersed in the slurry. For example, when the negative electrode current collector is coated with the slurry by screen printing, clogging of the screen (e.g., clogged by agglomerates of the negative electrode active material) can be suppressed.

[0190] The negative electrode active material layer may further include additives commonly used in all-solid-state batteries, such as fillers, coating agents, dispersants, ion conduction aids, etc.

[0191] The thickness of the negative electrode active material layer can be, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the thickness of the positive electrode active material layer. For example, the thickness of the negative electrode active material layer can be about 1 μm to about 20 μm, about 2 μm to about 10 μm, or about 3 μm to about 7 μm. When the negative electrode active material layer is too thin, lithium dendrites formed between the negative electrode active material layer and the negative electrode current collector can cause the negative electrode active material layer to collapse, making it difficult to improve the cycle characteristics of the all-solid-state battery. On the other hand, when the negative electrode active material layer is too thick, the energy density of the all-solid-state battery can be reduced, and the internal resistance of the all-solid-state battery through the negative electrode active material layer can increase, making it difficult to improve the cycle characteristics of the all-solid-state battery.

[0192] When the thickness of the negative electrode active material layer decreases, the charge capacity of the negative electrode active material layer may also decrease. For example, the charge capacity of the negative electrode active material layer may be 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, 5% or less, 2% or less, or 1% or less of the charge capacity of the positive electrode active material layer. For example, relative to the charge capacity of the positive electrode active material layer, the charge capacity of the negative electrode active material layer may be 0.1% to 50%, 0.1% to 40%, 0.1% to 30%, 0.1% to 20%, 0.1% to 10%, 0.1% to 5%, or 0.1% to 2%. When the charge capacity of the negative electrode active material layer is too small, the negative electrode active material layer becomes very thin, and thus lithium dendrites formed between the negative electrode active material layer and the negative electrode current collector during repeated charge and discharge processes may cause the negative electrode active material layer to collapse, making it difficult to improve the cycle characteristics of the all-solid-state battery. On the other hand, when the charge capacity of the negative electrode active material layer increases excessively, the energy density of the all-solid-state battery may decrease, and the internal resistance of the all-solid-state battery passing through the negative electrode active material layer may increase, making it difficult to improve the cycle characteristics of the all-solid-state battery.

[0193] The all-solid-state battery according to an embodiment may further include a metal layer disposed between the negative electrode current collector and the negative electrode active material layer. The metal layer may be a metal foil or a metal precipitation layer. The metal layer may include Li or a Li alloy. In this regard, the metal layer may serve as a lithium reservoir. For example, the Li alloy may include a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy, etc., but is not limited thereto. Any material available in the art as a lithium alloy may be used. The metal layer may include one of these alloys, lithium, or a combination of alloys.

[0194] The thickness of the metal layer is not particularly limited and may be, for example, about 1 μm to about 200 μm, about 1 μm to about 100 μm, about 1 μm to about 70 μm, about 1 μm to about 50 μm, about 1 μm to about 30 μm, or about 1 μm to about 20 μm. When the metal layer is too thin, the metal layer may not function well as a lithium reservoir. When the metal layer is too thick, the mass and volume of the all-solid-state battery may increase, and thus the cycle characteristics of the all-solid-state battery may deteriorate conversely. For example, the metal layer may be a metal foil having a thickness within the above range.

[0195] In a all-solid-state battery, the metal layer may be disposed, for example, between the negative electrode current collector and the negative electrode active material layer before the assembly of the all-solid-state battery, or may be deposited between the negative electrode current collector and the negative electrode active material layer by charging after the assembly of the all-solid-state battery. When the metal layer is disposed between the negative electrode current collector and the negative electrode active material layer before the assembly of the all-solid-state battery, since the metal layer contains lithium, the metal layer can act as a lithium reservoir. For example, before the assembly of the all-solid-state battery, a lithium foil may be disposed between the negative electrode current collector and the negative electrode active material layer. Therefore, the cycle characteristics of the all-solid-state battery including the metal layer can be further improved. When the metal layer is deposited by charging after the assembly of the all-solid-state battery, since the metal layer is not included during the assembly of the all-solid-state battery, the energy density of the all-solid-state battery can be increased. For example, when the all-solid-state battery is charged, the all-solid-state battery can be charged beyond the charging capacity of the negative electrode active material layer. In other words, the negative electrode active material layer can be overcharged. At the beginning of charging, Li can be adsorbed onto the negative electrode active material layer. The negative electrode active material included in the negative electrode active material layer can form an alloy or a compound with Li ions transmitted from the positive electrode. When charging exceeds the capacity of the negative electrode active material layer, Li can, for example, precipitate on the rear surface of the negative electrode active material layer (i.e., the surface between the negative electrode current collector and the negative electrode active material layer), and due to the precipitated Li, a metal layer corresponding to the metal layer can be formed. The metal layer can be a metal layer mainly composed of lithium (i.e., metallic lithium). For example, such a result can be obtained when the negative electrode active material included in the negative electrode active material layer is composed of a material that forms an alloy or a compound with Li. During discharging, Li included in the negative electrode active material layer and the metal layer, i.e., Li in the metal layer, can be ionized and move toward the positive electrode layer. In this regard, Li can be used as the negative electrode active material in the all-solid-state battery. In addition, since the metal layer is coated with the negative electrode active material layer, the negative electrode active material layer can act on the metal layer, i.e., as a protective layer for the metal layer, and at the same time, can be used to suppress the precipitation growth of lithium dendrites. Therefore, short-circuiting and capacity deterioration of the all-solid-state battery can be suppressed, and thus, the cycle characteristics of the all-solid-state secondary battery can be improved. In addition, when the metal layer is disposed by charging after the assembly of the all-solid-state battery, the negative electrode current collector, the negative electrode active material layer, and the region therebetween can be, for example, Li-free, i.e., not containing Li, in the initial state or the discharged state of the all-solid-state battery.

[0196] For example, the negative electrode current collector may be composed of a material that does not react with lithium (i.e., a material that neither forms an alloy nor a compound with lithium). Materials for forming the negative electrode current collector may be, for example, Cu, stainless steel, Ti, Fe, Co, Ni, etc., but are not limited thereto. Any material available in the art as an electrode current collector may be used. The negative electrode current collector may be composed of one of the above metals, or an alloy or coating material of two or more of the above metals. For example, the negative electrode current collector may be in the form of a plate or foil.

[0197] The all-solid-state battery may further include, for example, a thin film (not shown) on the negative electrode current collector, which includes an element capable of forming an alloy with Li. The thin film may be disposed between the negative electrode current collector and the negative electrode active material layer. For example, the thin film may include an element capable of forming an alloy with Li. For example, the element capable of forming an alloy with Li may include Au, Ag, Zn, Sn, In, Si, Al, Bi, etc., but is not limited thereto. Any element capable of forming an alloy with Li in the art may be used. The thin film may include one of these metals, or an alloy of multiple types of metals.

[0198] By depositing the thin film on the negative electrode current collector, for example, the deposition pattern of the metal layer deposited between the thin film and the negative electrode active material layer may be further flattened, and thus, the cycle characteristics of the all-solid-state battery may be further improved.

[0199] For example, the thickness of the thin film may be about 1 nm to about 800 nm, about 10 nm to about 700 nm, about 50 nm to about 600 nm, or about 100 nm to about 500 nm. When the thickness of the thin film is less than 1 nm, the thin film may be difficult to function. When the thin film is too thick, the thin film itself may adsorb Li, such that the amount of Li deposited in the negative electrode may be reduced, and thus, the energy density and cycle characteristics of the all-solid-state battery may deteriorate. For example, the thin film may be disposed on the negative electrode current collector by, for example, vacuum deposition method, sputtering method, plating method, etc., but is not limited thereto. Any method capable of forming a thin film in the art may be used.

[0200] Multi-layer ceramic (MLC) battery

[0201] The MLC battery may include, for example, a plurality of positive electrodes; a plurality of negative electrodes alternately disposed between the plurality of positive electrodes; and a solid electrolyte alternately disposed between the plurality of positive electrodes and the plurality of negative electrodes.

[0202] The MLC battery according to an embodiment may include: a plurality of positive electrodes, each including a positive electrode current collector and positive electrode active material layers disposed on both sides of the positive electrode current collector; a plurality of negative electrodes alternately disposed between the plurality of positive electrodes, each including a negative electrode current collector and negative electrode active material layers disposed on both sides of the negative electrode current collector; and a solid electrolyte alternately disposed between the plurality of positive electrodes and the plurality of negative electrodes, wherein at least one of the positive electrode active material layer or the negative electrode active material layer may include an oxide solid electrolyte, for example, a solid electrolyte including a solid ion conductor represented by Formula 1.

[0203] For example, the MLC battery may include a sintered product of a stack in which a positive electrode active material precursor, a negative electrode active material precursor, and a solid electrolyte precursor are sequentially stacked, or a sintered product of a stack in which a positive electrode active material, a negative electrode active material, and a solid electrolyte are sequentially stacked.

[0204] For example, the MLC battery may have a stack structure in which a plurality of unit cells are stacked such that the positive electrode active material layer and the negative electrode active material layer face each other, wherein the unit cell may include: a positive electrode including a positive electrode active material layer; a solid electrolyte; and a negative electrode including a negative electrode active material layer. For example, the MLC battery may further include a positive electrode current collector and / or a negative electrode current collector. When the MLC battery includes a positive electrode current collector, the positive electrode active material layer may be disposed on both sides of the positive electrode current collector. When the MLC battery includes a negative electrode current collector, the negative electrode active material layer may be disposed on both sides of the negative electrode current collector. When the MLC battery further includes a positive electrode current collector and / or a negative electrode current collector, the high-rate characteristics of the MLC battery may be further improved. In the MLC battery, the unit cells may be stacked by: providing a current collector layer on either or both of the uppermost layer and the lowermost layer of the stack, or by disposing a metal layer in the stack.

[0205] The MLC battery or the thin film battery may be, for example, a small or ultra-small battery that can be used as a power source for Internet of Things (IoT) applications or wearable devices. For example, the MLC battery or the thin film battery may also be applied to medium to large-sized batteries for electric vehicles (EVs), energy storage systems (ESSs), etc.

[0206] The negative electrode included in the MLC battery may include, for example, at least one negative electrode active material such as lithium metal phosphate, lithium metal oxide, metal oxide, or a carbon-containing negative electrode active material. For example, the negative electrode active material may be selected from Li 4 / 3 Ti 5 / 3O4, LiTiO2, LiM1 s M2 t O u (wherein M1 and M2 are each a transition metal, and s, t, and u are each positive numbers), TiOx (where 0 < x ≤ 3), or Li x compounds of V2(PO4)3 (where 0 < x ≤ 5). For example, the negative electrode active material may be Li 4 / 3 Ti 5 / 3 O4, LiTiO2, etc.

[0207] For example, the negative electrode active material may be a carbon-containing negative electrode active material. Examples of the carbon-containing negative electrode active material may include amorphous carbon, crystalline carbon, porous carbon, or a combination thereof. The crystalline carbon may include, for example, graphite of an amorphous type, plate type, flaky type, spherical type, or fiber type, such as natural graphite or artificial graphite.

[0208] The amorphous carbon may include, for example, CB, AB, FB, KB, graphene, soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc. The amorphous carbon may be carbon that does not have crystallinity or has very low crystallinity, which differentiates it from crystalline carbon.

[0209] The carbon-containing negative electrode active material may be, for example, porous carbon. The volume of pores in the porous carbon may be, for example, about 0.1 cubic centimeter per gram (cc / g) to about 10.0 cc / g, about 0.5 cc / g to about 5 cc / g, or about 0.1 cc / g to about 1 cc / g. The average diameter of pores in the porous carbon may be, for example, about 1 nm to about 50 nm, about 1 nm to about 30 nm, or about 1 nm to about 10 nm. The Brunauer-Emmett-Teller (BET) specific surface area of the porous carbon may be, for example, about 100 square meters per gram (m 2 / g) to about 3,000 m 2 / g.

[0210] The negative electrode active material may further include a solid electrolyte including a solid ion conductor represented by Formula 1. The negative electrode active material further including a solid electrolyte including a solid ion conductor represented by Formula 1 can achieve high density and high ionic conductivity at a low sintering temperature. In addition, the adhesion between the negative electrode active material and the solid electrolyte can be improved, thereby ensuring excellent MLC battery performance.

[0211] The positive electrode included in the MLC battery may include a positive electrode active material. The positive electrode active material may be selected from positive electrode active materials used in lithium ion batteries. For example, the positive electrode active material may include at least one of a lithium metal phosphorous oxide or a lithium metal oxide. For example, the positive electrode active material may include lithium cobalt oxide, lithium iron phosphorous oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese aluminum oxide, or a combination thereof. The positive electrode active material may further include a solid electrolyte including a solid ion conductor represented by Formula 1. The positive electrode active material further including a solid electrolyte including a solid ion conductor represented by Formula 1 may achieve high density and high ionic conductivity at a low sintering temperature. In addition, the adhesion between the positive electrode active material and the solid electrolyte may be improved, thereby ensuring excellent MLC battery performance.

[0212] For use as a current collector layer, any current collector that can be used as a positive electrode current collector and / or a negative electrode current collector may be used. For example, the current collector layer may be composed of any metal or alloy among Ni, Cu, Ag, Pd, Au, or Pt. For example, the alloy may be an alloy of two or more metals among Ni, Cu, Ag, Pd, Au, or Pt. For example, the alloy may be an Ag / Pd alloy. Such a metal or alloy may be used alone, or may be used as a mixture of two or more. The current collector layer as the positive electrode current collector and the current collector layer as the negative electrode current collector may be formed of the same or different materials. In an alloy or mixed powder of Ag / Pd, depending on the mixing ratio, the melting point may vary continuously and randomly from the melting point of Ag (962 °C) to the melting point of Pd (1,550 °C). In this regard, the melting point may be adjusted to immediately match the sintering temperature, and due to the high electron conductivity, an increase in the internal resistance of the MLC battery may be suppressed.

[0213] For example, the solid electrolyte may be an oxide solid electrolyte. The oxide solid electrolyte may be a solid electrolyte including a solid ion conductor represented by Formula 1. In addition to the solid electrolyte including a solid ion conductor represented by Formula 1, the oxide solid electrolyte may include oxide solid electrolytes used in the above fields.

[0214] For example, an MLC battery may be manufactured as follows.

[0215] Preparing a sheet. A solid electrolyte powder can be prepared to make a sheet. The solid electrolyte powder can be obtained by a mechanical grinding method of an oxide solid electrolyte (such as a solid electrolyte including a solid ion conductor represented by Formula 1). The mechanical grinding method can include ball milling, air jet milling, bead milling, roll milling, hand grinding, high-energy ball milling, planetary ball milling, stirred ball milling, vibration milling, mechanical alloying grinding, vibrator (shaker) milling, planetary grinding, grinder milling, disk milling, forming milling, nauta milling, nobilta milling, high-speed mixing, or a combination thereof. A solid electrolyte slurry or a solid electrolyte paste can be prepared by mixing the solid electrolyte powder with a binder, or by mixing the solid electrolyte powder, the binder, and a solvent. The binder can use the same material as the binder used in all-solid-state batteries. For use as a solvent, a solvent available in lithium batteries can be used. The solid electrolyte slurry or the solid electrolyte paste can be poured onto a doctor blade set at a predetermined height, and can be tape cast by using a PET substrate film or a carrier film moving at a speed of about 1.0 meter per minute (m / min) to about 3.0 m / min to prepare a sheet having a thickness of several micrometers to several tens of micrometers. Then, as described above, a plurality of positive electrodes, a plurality of negative electrodes alternately arranged between the plurality of positive electrodes, and the aforementioned sheet-shaped solid electrolyte alternately arranged between the plurality of positive electrodes and the plurality of negative electrodes can be stacked to manufacture a laminate. The manufactured laminate can be pressed by using an isostatic pressing method such as a warm isostatic pressing (WIP) method. The pressed laminate can be cut into chip sizes. The cut laminate can be sintered simultaneously with the electrode active material or sintered under reduced pressure to manufacture a sintered laminate from which the binder has been removed. The temperature for sintering simultaneously with the electrode active material can be about 400 °C to about 600 °C. For example, the temperature for sintering simultaneously with the electrode active material can be 450 °C or higher, 500 °C or higher, or 570 °C or lower, or 550 °C or lower. Tabs can be formed on the sintered laminate by using an electrode paste to complete the manufacture of the MLC battery.

[0216] Figure 1 Schematic cross-sectional view of an MLC battery according to an embodiment.

[0217] Referring to Figure 1, the positive electrode 110 is formed by disposing a positive electrode active material layer 112 on both sides of the positive electrode current collector 111. Similarly, the negative electrode 120 is formed by disposing a negative electrode active material layer 122 on both sides of the negative electrode current collector 121. The solid electrolyte 130 is disposed between the positive electrode 110 and the negative electrode 120. The external electrodes 140 may be formed at both ends of the battery body 150. The external electrodes 140 may be connected to the positive electrode 110 and the negative electrode 120, and the respective ends of the positive electrode 110 and the negative electrode 120 are exposed to the outside of the battery body 150. In this regard, the external electrodes 140 may serve as external terminals for electrically connecting the positive electrode 110, the negative electrode 120, and the external electrodes 140. One of the pair of external electrodes 140 may be connected to the positive electrode 110 whose end is exposed to the outside of the battery body 150, and the other of the pair of external electrodes 140 may be connected to the negative electrode 120 whose end is exposed to the outside of the battery body 150. In the MLC battery, the positive electrode 110 including the positive electrode active material layer 112, the solid electrolyte including the vitreous solid electrolyte, and the negative electrode 120 including the negative electrode active material layer 122 (which is carbon-containing) may be sequentially stacked, and then, the electrode active materials and the solid electrolyte including the vitreous solid ion conductor may be sintered simultaneously to form the solid electrolyte 130 including the solid ion conductor having crystals. Figure 2 and 3 are schematic views showing cross-sectional structures of MLC batteries according to additional embodiments. As Figure 2 shown, in the MLC battery 710, the first single cell and the second single cell may be stacked through the internal current collector layer 74. Each of the first single cell and the second single cell may be composed of a positive electrode layer 71, a solid electrolyte layer 73, and a negative electrode layer 72 stacked in sequence. The first single cell, the second single cell, and the internal current collector layer 74 may be stacked in the following manner: the negative electrode layer 72 of the second single cell is adjacent to one side of the internal current collector layer 74 (i.e., Figure 2 the top surface in Figure 2 ), and the negative electrode layer 72 of the first single cell is adjacent to the other side of the internal current collector layer 74 (i.e., Figure 2In it, the internal current collector layer 74 is arranged to contact the negative electrode layers 72 of the first single cell and the second single cell respectively, but the internal current collector layer 74 can be arranged to contact the positive electrode layers 71 of the first single cell and the second single cell respectively. The internal current collector layer 74 may include an electron-conducting material. The internal current collector layer 74 may further include an ion-conducting material. By further including the ion-conducting material, the voltage stabilization characteristics can be improved. Then, the same poles can be arranged on both sides of the internal current collector layer 74 in the MLC cell 710, and thus a single-pole type MLC cell 710 in which a plurality of single cells are connected in parallel through the internal current collector layer 74 can be obtained. Therefore, a high-capacity MLC cell 710 can be obtained. In the MLC cell 710, the internal current collector layer 74 arranged between the first single cell and the second single cell may include an electron-conducting material. In this regard, two adjacent single cells can be electrically connected in parallel, and at the same time, the internal current collector 74 can be connected to the positive electrode layer 71 or the negative electrode layer 72 of two adjacent single cells in an ion-conducting manner. Therefore, the electric potential of the positive electrode layer 71 or the negative electrode layer 72 adjacent to the internal current collector layer 74 can be averaged through the internal current collector layer 74, so that a stable output voltage can be obtained. In addition, an external current collecting member (such as a tab) can be eliminated, and the single cells constituting the MLC cell 710 can be electrically connected in parallel. Therefore, an MLC cell 710 with excellent space utilization and economic efficiency can be obtained. Refer to Figure 3 The laminate may include a positive electrode layer 81, a negative electrode layer 82, a solid electrolyte layer 83, and an internal current collector layer 84. Such a laminate can be stacked and thermally compressed to obtain a stacked MLC cell 810. The positive electrode layer 81 may be composed of a single sheet for the positive electrode layer. The negative electrode layer 82 may be composed of two sheets for the negative electrode layer.

[0218] Hereinafter, embodiments and comparative examples of the present disclosure will be described. However, the following embodiments are only examples of the present disclosure, and the present disclosure is not limited thereto.

[0219] Embodiments

[0220] Preparation of Solid Ion Conductor

[0221] Example 1: Li4B 5.1 Al 1.8 Sb 0.1 O 12 Solid ion conductor of Cl

[0222] To obtain Li4B 5.1 Al 1.8 Sb 0.1 O 12For the glassy solid ion conductor of Cl, Li2CO3, B2O3, Al2O3, Sb2O3 and LiCl were added to the reactor in stoichiometric proportions. The raw materials were mixed for 15 minutes at 500 rpm using a planetary mill (Pulverisette 7 premium line) loaded with zirconia (YSZ) balls having a diameter of 10 millimeters (mm), and then left standing for 5 minutes. This mixing and standing cycle was repeated 3 hours to obtain a milled mixture. The milled mixture was added to a crucible and preheated at about 1,000 °C for 5 hours to obtain a melt. The melt was dropped between two rollers and quenched to 200 °C or lower within a cooling time of 1 second, and then subjected to screen printing to prepare Li4B 5.1 Al 1.8 Sb 0.1 O 12 The glassy ion conductor of Cl. The Li4B thus prepared 5.1 Al 1.8 Sb 0.1 O 12 The glassy ion conductor of Cl was added to a furnace in an air atmosphere and heat-treated at about 540 °C for about 30 minutes to prepare a ceramic solid ion conductor having Li4B 5.1 Al 1.8 Sb 0.1 O 12 Cl crystals.

[0223] Example 2: Li4B5Al 1.8 Sb 0.2 O 12 The solid ion conductor of Cl

[0224] Having Li4B5Al 1.8 Sb 0.2 O 12 The ceramic solid ion conductor of Cl crystals was prepared in the same manner as in Example 1, except that: Li2CO3, B2O3, Al2O3, Sb2O3 and LiCl were added to the reactor in stoichiometric proportions to obtain Li4B5Al 1.8 Sb 0.2 O 12 The glassy solid ion conductor of Cl.

[0225] Example 3: Li4B 4.9 Al 1.8 Sb 0.3 O 12 The solid ion conductor of Cl

[0226] Having Li4B 4.9 Al 1.8 Sb 0.3 O12 The ceramic solid ion conductor of LiCl was prepared in the same manner as in Example 1, except that: Li2CO3, B2O3, Al2O3, Sb2O3 and LiCl were added to the reactor in stoichiometric proportions to obtain Li4B 4.9 Al 1.8 Sb 0.3 O 12 Cl glassy solid ion conductor.

[0227] Example 4: Li4B 4.6 Al 1.8 Sb 0.6 O 12 Cl solid ion conductor

[0228] Having Li4B 4.6 Al 1.8 Sb 0.6 O 12 The ceramic solid ion conductor of LiCl was prepared in the same manner as in Example 1, except that: Li2CO3, B2O3, Al2O3, Sb2O3 and LiCl were added to the reactor in stoichiometric proportions to obtain Li4B 4.6 Al 1.8 Sb 0.6 O 12 Cl glassy solid ion conductor.

[0229] Example 5: Li4B 4.9 Al 1.8 Sb 0.3 O 12 Cl and Li4B4Al3O 12 Cl composite solid ion conductor

[0230] Including Li4B 4.9 Al 1.8 Sb 0.3 O 12 Cl crystals and Li4B4Al3O 12 Cl crystals of the ceramic composite solid ion conductor were prepared in the same manner as in Example 1, except that: a mixed raw material of a first raw material and a second raw material mixed in a volume ratio of 50:50 was used, wherein the first raw material was obtained by adding Li2CO3, B2O3, Al2O3, Sb2O3 and LiCl to the reactor in stoichiometric proportions to obtain Li4B 4.9 Al 1.8 Sb 0.3 O 12prepared from a glassy solid ion conductor of Cl, and the second raw material is obtained by adding Li2CO3, B2O3, Al2O3, and LiCl to a reactor in stoichiometric proportions to obtain Li4B4Al3O 12 prepared from a glassy solid ion conductor of Cl.

[0231] Comparative Example 1: Li4B4Al3O 12 solid ion conductor of Cl

[0232] Having Li4B4Al3O 12 A ceramic solid ion conductor having Li4B4Al3O 12 Cl crystals was prepared in the same manner as in Example 1, except that: Li2CO3, B2O3, Al2O3, and LiCl were added to a reactor in stoichiometric proportions to obtain Li4B4Al3O

[0233] Evaluation Example 1: ICP analysis

[0234] The compositions of the glassy solid ion conductors of Examples 1 to 4 were analyzed using an inductively coupled plasma spectrometer (ICP), and the results are shown in Table 1.

[0235] Table 1

[0236]

[0237] Referring to Table 1, it is demonstrated that the designed compositions of the glassy solid ion conductors of Examples 1 to 4 closely match the compositions measured by ICP analysis.

[0238] Evaluation Example 2: X-ray diffraction analysis

[0239] Before and after heat treatment of the glassy solid ion conductors of Comparative Example 1 and Examples 1 to 4, the phases of the glassy solid ion conductors and the ceramic solid ion conductors including crystals were analyzed by X-ray diffraction (XRD) and with the naked eye. For the XRD analysis, the XRD spectra were measured using X'pert pro (PANalytical) with CuKα radiation (1.54056 Å, ).

[0240] (1) Glassy solid ion conductor

[0241] The results of measuring the XRD spectra for each glassy solid ion conductor are shown in Figure 4 .

[0242] Referring to Figure 4, the vitreous solid ion conductors of Comparative Example 1 and Examples 1 to 4 all have an amorphous phase and have no definite (well-defined, defined) peaks for diffraction angles between 10° 2θ and 60° 2θ. That is, it is proved that the vitreous solid ion conductors prepared in Comparative Example 1 and Examples 1 to 4 are well formed regardless of the Sb doping amount.

[0243] In addition, the devitrification of each vitreous solid ion conductor is observable with the naked eye. Here, the term "devitrification" refers to the formation of crystals in the glass and the loss of transparency in the regions where the crystals are formed. As a result of macroscopic observation, it is proved that the vitreous solid ion conductors prepared in Examples 1 to 4 and Comparative Example 1 do not show devitrification phenomena, indicating that all the vitreous solid ion conductors remain in the amorphous phase.

[0244] (2) Ceramic solid ion conductors having crystals

[0245] The XRD spectra of each solid ion conductor having crystals are shown in Figure 5 .

[0246] Referring to Figure 5 , it is proved that the ceramic solid ion conductors having crystals prepared in Comparative Example 1 and Examples 1 to 4 all have a main peak at a diffraction angle of 24° 2θ ± 1° 2θ and secondary peaks at diffraction angles of 13° 2θ ± 1° 2θ, 19° 2θ ± 1° 2θ, 23° 2θ ± 1° 2θ, and 42° 2θ ± 1° 2θ, indicating the crystallization of the ceramic solid ion conductors. As the Sb doping amount increases in the vitreous solid ion conductors prepared in Examples 1 to 4 (Examples 3 and 4), second phases such as LiSbO3, Li4AlSbO6, and Sb2O3 are generated.

[0247] In addition, the devitrification of each solid ion conductor having crystals is observed with the naked eye. As a result of macroscopic observation, it is proved that the ceramic solid ion conductors having crystals prepared in Comparative Example 1 and Examples 1 to 4 all show devitrification phenomena similar to crystallization.

[0248] Evaluation Example 3: DSC and gas pycnometer analysis

[0249] For the vitreous solid ion conductors of Examples 1 to 4, the results of measuring the glass transition temperature (T g ), the initial thermal decomposition temperature (T s ), and the crystallization temperature (T c ) by differential scanning calorimetry (DSC), and the results of measuring the density (g / cm 3 ) using a gas pycnometer are shown in Table 2, and the results for the vitreous solid ion conductors of Examples 1, 2, and 4 are shown in Figure 6 .

[0250] For the DSC spectrum analysis, a DSC differential scanning calorimeter manufactured by PerkinElmer was used to heat from room temperature to 600 °C at a heating rate of 10 °C / minute under a N2 atmosphere. The DSC spectrum is an "Endo up" spectrum, which means that the peak direction is upward for endothermic reactions and downward for exothermic reactions, and the number written on the peak is the crystallization temperature (T c ).

[0251] For the density analysis using a gas pycnometer, the sample weighed using a Micromeritics device was placed in the sample chamber, and the volume of the sample was measured by the change in pressure relative to a reference chamber with a known volume. The density value was calculated by applying the measured values to the equation of the ideal gas law (PV = nRT).

[0252] Table 2

[0253]

[0254] Referring to Table 2 and Figure 6 , the vitreous solid ion conductors of Examples 1 to 4 have a glass transition temperature T g of 432 °C or lower and a crystallization temperature T c of 550 °C or lower. In addition, the vitreous solid ion conductors of Examples 1 to 4 have a density that is generally high, from 2.24 g / cm 3 to 2.52 g / cm 3 .

[0255] Evaluation Example 4: SEM analysis

[0256] 500-μm-thick 316SS and 304SS spacers were applied as blocking electrodes on both sides of the crushed glass (thickness: 400 μm) of the vitreous solid ion conductors of Examples 1 to 4, and they were heat treated (hereinafter referred to as "hot press sintering" (HPS)) at a pressure of 50 MPa and a temperature of 550 °C. Then, the obtained sintered product was clamped with pliers, and the fracture surface was analyzed by scanning electron microscopy (SEM). The results are shown in Figure 7A , 7B , 7C and 7D.

[0257] Referring to Figure 7A , 7B , 7C and 7D, the fracture surfaces of the crushed glass of the vitreous solid ion conductors of Examples 1 to 4 that have been crystallized by HPS show a very dense microstructure with few pores.

[0258] Therefore, it can be confirmed that when manufacturing a lithium battery by including a solid ion conductor crystallized from the vitreous solid ion conductors of Examples 1 to 4 in the solid electrolyte, the energy density will be improved.

[0259] Evaluation Example 5: Analysis of Ionic Conductivity and Electronic Conductivity

[0260] Without polishing the surface, the crushed glass (thickness: 400 μm) of the vitreous solid ion conductors of Comparative Example 1 and Examples 1 to 4 was heat-treated in an air box furnace at 550 °C for 30 minutes (hereinafter referred to as "box sintering") to prepare specimens. Gold (Au) electrodes were formed on both sides of the specimens by depositing a 200-nm-thick Au paste with 5π(Φ) pores on top using the sputtering method. Wires were connected to the Au electrodes on both sides of the specimens, and analysis was performed by electrochemical impedance spectroscopy (EIS).

[0261] The EIS analysis was performed with an amplitude of approximately 10 millivolts (mV) and a frequency from 1 hertz (Hz) to 10 6 Hz. As the impedance analyzer, a potentiostat / galvanostat and a 1455 frequency response analyzer (FRA) multi-channel test module (Solatron Analytical, UK) were used. The impedance of the crushed glass was measured at room temperature (25 °C) using the two-probe method. The resistance value was obtained from the arc of the Nyquist curve for the impedance measurement results, and the electronic conductivity was calculated as the reciprocal of the resistance value. Then, the ionic conductivity was calculated by correcting the electrode area and the thickness of the crushed glass. The ionic conductivity was divided by the electronic conductivity to calculate the value. The results are shown in Table 3 and Figure 8 in.

[0262] Table 3

[0263] Electronic conductivity (S / cm) Ionic conductivity (S / cm) Ionic conductivity / Electronic conductivity Comparative Example 1 <![CDATA[2.0x 10 -9 > <![CDATA[1.6x 10 -6 > <![CDATA[8.4x 10 2 > Example 1 <![CDATA[1.7x 10 -9 > <![CDATA[3.4x 10 -6 > <![CDATA[1.9x 10 3 > Example 2 <![CDATA[2.2x 10 -9 > <![CDATA[4.4x 10 -6 > <![CDATA[2.0x 10 3 > Example 3 <![CDATA[6.3x 10 -9 > <![CDATA[3.5x 10 -6 > <![CDATA[5.5x 10 2 > Example 4 <![CDATA[6.4x 10 -9 > <![CDATA[3.6x 10 -6 > <![CDATA[5.6x 10 2 >

[0264] Referring to Table 3 and Figure 8 , the ionic conductivity range of the solid ion conductors crystallized by box sintering of the crushed glass of the vitreous solid ion conductors of Examples 1 to 4 was from 3.4x10 -6 S cm -1 to up to 4.4x10 -6 S cm -1 . Compared with the solid ion conductor obtained by crystallizing the crushed glass of the vitreous solid ion conductor of Comparative Example 1, the ionic conductivity of the solid ion conductor obtained by crystallizing the crushed glass of the vitreous solid ion conductor of Example 2 was improved by about 2.7 times.

[0265] In addition, the crushed glass of the vitreous solid ion conductor of Example 2 (thickness: 400 μm) was heat-treated (HPS) at a pressure of 50 MPa and a temperature of 550 °C in the same manner as in Evaluation Example 4 by using spacers as blocking electrodes to prepare specimens. Wires were connected to the spacers serving as blocking electrodes on both sides of the specimens, and EIS analysis was performed in the same manner as in Evaluation Example 5 to calculate the electronic conductivity, ionic conductivity, and ionic conductivity / electronic conductivity.

[0266] Therefore, the results of the electronic conductivity, ionic conductivity, and ionic conductivity / electronic conductivity of the solid ion conductor crystallized by box sintering and HPS of the crushed glass of the vitreous solid ion conductor of Example 2 are shown in Table 4 and Figure 9 .

[0267] Table 4

[0268]

[0269] Referring to Table 4 and Figure 9 , the ionic conductivity of the solid ion conductor crystallized by HPS of the crushed glass of the vitreous solid ion conductor of Example 2 is excellent, being 1.2x10 -5 S / cm.

[0270] Therefore, the solid electrolyte including the glass-ceramic solid ion conductor of the present disclosure can achieve high density and high ionic conductivity at a low sintering temperature, and can be applied to MLC batteries laminated with multiple thin film layers.

[0271] According to one or more embodiments, the solid electrolyte may include a solid ion conductor represented by Formula 1. The solid electrolyte including the solid ion conductor can achieve high density and high ionic conductivity at a low sintering temperature.

[0272] It should be understood that the embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. The description of features or aspects in each embodiment should typically be considered applicable to other similar features or aspects in other embodiments. Although one or more embodiments have been described with reference to the accompanying drawings, those of ordinary skill in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope as defined by the appended claims.

Claims

1. A solid electrolyte comprising a solid ion conductor represented by Formula 1: Formula 1 Li a B b Al m Q n O c X d Among them, In Formula 1, Q is an element having an ionic radius that differs from that of Al by less than 30% and having +3 and +5 valence states, X is at least one of F, Cl, Br, or I, 3.5 ≤ a ≤ 4.5, 3 ≤ b < 5.2, 1 ≤ m ≤ 3, 0 < n < 2, 11 ≤ c ≤ 13, and 0 < d ≤ 1.

5.

2. The solid electrolyte according to claim 1, wherein In Formula 1, the ionic radius of Q is from 50 picometers to 100 picometers.

3. The solid electrolyte according to claim 1, wherein In Formula 1, Q includes at least one of Sb or V.

4. The solid electrolyte according to claim 1, wherein In Formula 1, Q is a substitution dopant that substitutes at least one of B or Al in Formula 1.

5. The solid electrolyte according to claim 1, wherein the solid ion conductor comprises at least one of the following: Li4B 5.1 Al 1.8 Sb 0.1 O 12 F, Li4B5Al 1.8 Sb 0.2 O 12 F, Li4B 4.9 Al 1.8 Sb 0.3 O 12 F, Li4B 4.8 Al 1.8 Sb 0.4 O 12 F, Li4B 4.7 Al 1.8 Sb 0.5 O 12 F, Li4B 4.6 Al 1.8 Sb 0.6 O 12 F, Li4B 4.5 Al 1.8 Sb 0.7 O 12 F, Li4B 4.4 Al 1.8 Sb 0.8 O 12 F, or Li4B 4.3 Al 1.8 Sb 0.9 O 12 F, Li4B 5.1 Al 1.8 Sb 0.1 O 12 Cl, Li4B5Al 1.8 Sb 0.2 O 12 Cl, Li4B 4.9 Al 1.8 Sb 0.3 O 12 Cl, Li4B 4.8 Al 1.8 Sb 0.4 O 12 Cl, Li4B 4.7 Al 1.8 Sb 0.5 O 12 Cl, Li4B 4.6 Al 1.8 Sb 0.6 O 12 Cl, Li4B 4.5 Al 1.8 Sb 0.7 O 12 Cl, Li4B 4.4 Al 1.8 Sb 0.8 O 12 Cl, Li4B 4.3 Al 1.8 Sb 0.9 O 12 Cl, Li4B 5.1 Al 1.8 Sb 0.1 O 12 Br, Li4B5Al 1.8 Sb 0.2 O 12 Br, Li4B 4.9 Al 1.8 Sb 0.3 O 12 Br, Li4B 4.8 Al 1.8 Sb 0.4 O 12 Br, Li4B 4.7 Al 1.8 Sb 0.5 O 12 Br, Li4B 4.6 Al 1.8 Sb 0.6 O 12 Br, Li4B 4.5 Al 1.8 Sb 0.7 O 12 Br, Li4B 4.4 Al 1.8 Sb 0.8 O 12 Br, Li4B 4.3 Al 1.8 Sb 0.9 O 12 Br, Li4B 5.1 Al 1.8 Sb 0.1 O 12 I, Li4B5Al 1.8 Sb 0.2 O 12 I, Li4B 4.9 Al 1.8 Sb 0.3 O 12 I, Li4B 4.8 Al 1.8 Sb 0.4 O 12 I, Li4B 4.7 Al 1.8 Sb 0.5 O 12 I, Li4B 4.6 Al 1.8 Sb 0.6 O 12 I, Li4B 4.5 Al 1.8 Sb 0.7 O 12 I, Li4B 4.4 Al 1.8 Sb 0.8 O 12 I, Li4B 4.3 Al 1.8 Sb 0.9 O 12 I, Li4B 5.1 Al 1.8 V 0.1 O 12 F, Li4B5Al 1.8 V 0.2 O 12 F, Li4B 4.9 Al 1.8 V 0.3 O 12 F, Li4B 4.8 Al 1.8 V 0.4 O 12 F, Li4B 4.7 Al 1.8 V 0.5 O 12 F, Li4B 4.6 Al 1.8 V 0.6 O 12 F, Li4B 4.5 Al 1.8 V 0.7 O 12 F, Li4B 4.4 Al 1.8 V 0.8 O 12 F, Li4B 4.3 Al 1.8 V 0.9 O 12 F, Li4B 5.1 Al 1.8 V 0.1 O 12 Cl, Li4B5Al 1.8 V 0.2 O 12 Cl, Li4B 4.9 Al 1.8 V 0.3 O 12 Cl, Li4B 4.8 Al 1.8 V 0.4 O 12 Cl, Li4B 4.7 Al 1.8 V 0.5 O 12 Cl, Li4B 4.6 Al 1.8 V 0.6 O 12 Cl, Li4B 4.5 Al 1.8 V 0.7 O 12 Cl, Li4B 4.4 Al 1.8 V 0.8 O 12 Cl, Li4B 4.3 Al 1.8 V 0.9 O 12 Cl, Li4B 5.1 Al 1.8 V 0.1 O 12 Br, Li4B5Al 1.8 V 0.2 O 12 Br, Li4B 4.9 Al 1.8 V 0.3 O 12 Br, Li4B 4.8 Al 1.8 V 0.4 O 12 Br, Li4B 4.7 Al 1.8 V 0.5 O 12 Br, Li4B 4.6 Al 1.8 V 0.6 O 12 Br, Li4B 4.5 Al 1.8 V 0.7 O 12 Br, Li4B 4.4 Al 1.8 V 0.8 O 12 Br, Li4B 4.3 Al 1.8 V 0.9 O 12 Br, Li4B 5.1 Al 1.8 V 0.1 O 12 I, Li4B5Al 1.8 V 0.2 O 12 I, Li4B 4.9 Al 1.8 V 0.3 O 12 I, Li4B 4.8 Al 1.8 V 0.4 O 12 I, Li4B 4.7 Al 1.8 V 0.5 O 12 I, Li4B 4.6 Al 1.8 V 0.6 O 12 I, Li4B 4.5 Al 1.8 V 0.7 O 12 I, Li4B 4.4 Al 1.8 V 0.8 O 12 I, or Li4B 4.3 Al 1.8 V 0.9 O 12 I.

6. The solid electrolyte according to claim 1, wherein the solid ion conductor is at least one of a glassy solid ion conductor or a crystalline solid ion conductor.

7. The solid electrolyte according to claim 1, wherein when measured by differential scanning calorimetry of the solid ion conductor, the solid electrolyte has a crystallization temperature of 400°C to 600°C and a glass transition temperature of 400°C to 432°C.

8. The solid electrolyte according to claim 1, wherein when measured by a gas pycnometer, the solid electrolyte has a density of 1.5 g / cm³ to 3.0 g / cm³.

9. The solid electrolyte according to claim 1, wherein the solid ion conductor has an ionic conductivity of 3.4 x 10 -6 Siemens / cm to 5.0 x 10 -6 Siemens / cm at 25 °C.

10. The solid electrolyte according to claim 1, wherein the solid electrolyte further comprises a composite solid ion conductor, the composite solid ion conductor comprising a crystalline solid ion conductor represented by Formula 2: Formula 2 Li a1 B b1 Al m1 O c1 X d1 Among them, In Formula 2, X is at least one of F, Cl, Br, or I, 3.5 ≤ a1 ≤ 4.5, 3 ≤ b1 < 5.2, 1 ≤ m1 ≤ 3, 11 ≤ c1 ≤ 13, and 0 < d1 ≤ 1.

5.

11. The solid electrolyte according to claim 1, wherein the solid electrolyte has a thickness of 0.1 micrometer to 30 micrometers.

12. A method for manufacturing the solid electrolyte according to any one of claims 1 - 5 and 7 - 11, the method comprising: Mechanically grinding a lithium source, a boron source, an aluminum source, a Q element source, and a halogen source to provide a glassy solid ion conductor; And Heat - treating the glassy solid ion conductor at a temperature equal to or higher than the initial thermal decomposition temperature of the glassy solid ion conductor measured by differential scanning calorimetry to provide a crystal - containing solid ion conductor represented by Formula 1.

13. The method according to claim 12, wherein the providing of the glassy solid ion conductor further comprises, after mechanical grinding, pre - heat - treating and quenching at a temperature in the range of 600°C to 1,300°C.

14. The method according to claim 12, wherein the Q element source comprises at least one of Sb2O3, Sb2O5, V2O3, V2O5, SbF3, SbF5, SbCl3, SbCl5, SbCl2F3, SbCl3F2, Sb(NO3)3, Sb(OH)3, or Sb(OH)5.

15. The method according to claim 12, wherein the production of the crystalline solid ion conductor comprises heat-treating the vitreous solid ion conductor in an air atmosphere, or providing insulating films on both sides of the vitreous solid ion conductor and then heat-treating.

16. The method according to claim 12, wherein In the production of the crystalline solid ion conductor, the vitreous solid ion conductor is heat-treated at a temperature of 600 °C or lower for 5 minutes to 2 hours.

17. The method according to claim 12, wherein, In the production of the crystalline solid ion conductor, insulating films are arranged on both sides of the vitreous solid ion conductor, and heat-treatment is carried out under a pressure of 1 MPa to 50 MPa and at a temperature of 400 °C to 600 °C.

18. A lithium battery, comprising: a positive electrode, a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode, wherein at least one of the positive electrode, the negative electrode, or the solid electrolyte layer comprises the solid electrolyte according to any one of claims 1-11.

19. The lithium battery according to claim 18, wherein the lithium battery is a lithium-ion battery, an all-solid-state battery, or a multilayer ceramic (MLC) battery.

20. The lithium battery according to claim 18, wherein the lithium battery comprises: a plurality of positive electrodes, each comprising a positive electrode current collector and positive electrode active material layers disposed on both sides of the positive electrode current collector; a plurality of negative electrodes, each comprising a negative electrode current collector and negative electrode active material layers disposed on both sides of the negative electrode current collector, wherein the plurality of negative electrodes are alternately disposed between the plurality of positive electrodes; and a solid electrolyte alternately disposed between the plurality of positive electrodes and the plurality of negative electrodes, wherein at least one of the positive electrode active material layer or the negative electrode active material layer comprises the solid electrolyte according to any one of claims 1-11.

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