Solid electrolyte for all solid-state battery and solid-state battery comprising the same

Abstract

This invention relates to a solid electrolyte for an all-solid-state battery and an all-solid-state battery comprising the same. According to one embodiment of the invention, the solid electrolyte for an all-solid-state battery is formed from an oxide comprising Li, B, Al, Cl, and an alkaline earth metal.

Description

[Technical Field]

[0001] This invention relates to a solid electrolyte for an all-solid-state battery and an all-solid-state battery comprising the same. [Previous Technology]

[0002] Renewable batteries are used in various fields, from IT devices such as mobile phones to electric vehicles and energy storage devices.

[0003] As a secondary battery, lithium-ion batteries using liquid electrolytes are the most widely used. However, when an external impact is applied to the battery, there is a risk of leakage of the liquid electrolyte, so additional parts and devices are needed to ensure safety.

[0004] In recent years, to improve the safety of lithium-ion batteries, there has been active development of all-solid-state lithium-ion batteries using solid electrolytes. Solid electrolytes for all-solid-state lithium-ion batteries include polymer electrolytes, oxide electrolytes, and sulfide electrolytes. Among them, sulfide solid electrolytes have excellent electrochemical performance due to their high ionic conductivity and particle deformability, but they have the problem of reacting with moisture in the air to produce toxic hydrogen sulfide gas. Polymer electrolytes have the advantage of relatively simple manufacturing processes and the ability to use existing lithium-ion battery processes, but they have the disadvantage of significantly low ionic conductivity.

[0005] Although oxide-based electrolytes have lower ionic conductivity than sulfide-based electrolytes, their ionic conductivity is relatively high, offering the advantage of excellent safety. Currently, oxide-based solid electrolytes with high ionic conductivity (above 10⁻⁴ S / cm), such as LAGP and LLZO, are under development. However, these solid electrolytes face limitations in improving electrochemical performance due to their narrow electrochemical voltage range and high-temperature sintering processes (above 1000℃), leading to increased production costs and potentially limited availability. [Summary of the Invention]

[0006] The present invention is intended to solve the problems of the prior art described above, and its object is to provide an oxide-based solid electrolyte for all-solid-state batteries that can be sintered at low temperatures and has excellent ionic conductivity, and an all-solid-state battery containing the same.

[0007] According to an embodiment of the present invention, the solid electrolyte for an all-solid-state battery is formed from an oxide containing Li, B, Al, Cl and alkaline earth metals.

[0008] According to one embodiment of the present invention, the alkaline earth metal can be at least one of Ba, Ca, Mg and Sr.

[0009] According to one embodiment of the present invention, it may contain 0.4 to 11 mol% alkaline earth metals.

[0010] According to one embodiment of the present invention, it may contain 0.4 to 10 mol% alkaline earth metals.

[0011] According to an embodiment of the present invention, the solid electrolyte for an all-solid-state battery may contain 21 to 29 mol% Li2O, 24 to 46 mol% B2O3, 9 to 21 mol% Al2O3 and 16 to 31 mol% LiCl.

[0012] According to an embodiment of the present invention, the solid electrolyte for an all-solid-state battery can be manufactured from precursor powders containing Li2CO3, H3BO3, Al2O3, LiCl and alkaline earth metal oxides.

[0013] According to an embodiment of the present invention, the ionic conductivity of the solid electrolyte for an all-solid-state battery can be 1.1×10-5S / cm or higher.

[0014] An all-solid-state battery according to an embodiment of the present invention may include an anode layer, a cathode layer and a solid electrolyte layer, wherein the solid electrolyte layer may be formed of an oxide comprising Li, B, Al, Cl and alkaline earth metals.

[0015] Furthermore, the solid electrolyte for all-solid-state batteries according to the present invention may further include other additional components without impairing the technical concept of the present invention.

[0016] [Effects of the Invention]

[0017] According to one embodiment of the present invention, the solid electrolyte for all-solid-state batteries is an oxide-based solid electrolyte, which is formed from oxides containing Li, B, Al, Cl and alkaline earth metals, thereby enabling low-temperature sintering and exhibiting excellent ionic conductivity.

Implementation Method

[0023] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings to a degree that can be easily implemented by those skilled in the art to which the present invention pertains.

[0024] To clearly illustrate the present invention, descriptions of parts unrelated to the present invention have been omitted, and the same reference numerals are used to denote the same constituent elements throughout the specification. It should be understood that the specific shapes, structures, and characteristics described in the specification can be implemented by changing one embodiment to other embodiments without departing from the spirit and scope of the present invention, and the position or arrangement of individual constituent elements can also be changed without departing from the spirit and scope of the present invention.

[0025] Therefore, the detailed description that follows is not intended to be restrictive, but should be understood as including the scope of the claims in the claims and all equivalent scopes thereof.

[0026] Figure 1 is a schematic perspective view of the all-solid-state battery, and Figure 2 is a schematic cross-sectional view of the all-solid-state battery. The all-solid-state battery of one embodiment disclosed herein is a so-called multilayer ceramic battery, which can be formed in the form of a wafer and can be used in small electronic devices such as wearable electronic devices.

[0027] Referring to Figures 1 and 2, the all-solid-state battery (10) includes an anode layer (11), a cathode layer (12), and a solid electrolyte layer (13). The solid electrolyte layer (13) is disposed between the anode layer (11) and the cathode layer (12) and can contact the anode layer (11) and the cathode layer (12) respectively. The anode layer (11) and the cathode layer (12) can each have a current collector and an active material layer. The active material layer of the electrode layer can be coated and formed on at least one side of each current collector and contact the solid electrolyte layer (13).

[0028] In one embodiment, the anode layer (11) can be formed by coating at least one side of the anode current collector with an anode active material layer, and the cathode layer (12) can be formed by coating at least one side of the cathode current collector with a cathode active material layer. For example, the electrode layer located at the uppermost segment based on the stacking direction can be formed by coating one side of the anode current collector with an anode active material layer, and the electrode layer located at the lowermost segment can be formed by coating one side of the cathode current collector with a cathode active material layer. Moreover, the electrode layer located between the uppermost and lowermost segments can be formed by coating both sides of the anode current collector with an anode active material layer, or by coating both sides of the cathode current collector with a cathode active material layer.

[0029] The anode active material layer may contain an anode active material and may optionally contain a solid electrolyte. Furthermore, the anode active material layer may optionally contain additives such as binders or conductive agents.

[0030] The anode active material is not particularly limited as long as it can ensure sufficient capacity of the all-solid-state battery (10). For example, the anode active material may include lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphorus oxide, lithium manganese oxide, or a combination thereof.

[0031] The conductive agent in the anode active material layer is not particularly restricted as long as it does not induce chemical changes in the all-solid-state battery (10) and is conductive. For example, as a conductive agent, carbon-based materials such as natural graphite or artificial graphite, carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black, conductive fibers such as carbon fiber or metal fiber, fluorinated carbon, aluminum powder, nickel powder, conductive zinc oxide, potassium titanate, conductive metal oxides such as titanium oxide, and conductive materials such as polyphenylene derivatives can be used.

[0032] To improve the bonding strength between the active material and the conductive agent, an adhesive can be used. As an adhesive, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, or various copolymers can be used.

[0033] As the anode current collector, a porous body such as a mesh or a perforated shape can be used, and porous metal plates such as stainless steel, nickel, and aluminum can be used. Furthermore, to prevent oxidation, the anode current collector can be coated with an oxidation-resistant metal or alloy film.

[0034] The cathode active material layer may contain cathode active material and may optionally contain solid electrolyte. Furthermore, the cathode active material layer may optionally contain additives such as binders or conductive agents.

[0035] The cathode active material may be carbon-based materials, silicon, silicon oxides, silicon alloys, silicon-carbon composites, tin, tin alloys, tin-carbon composites, metal oxides or combinations thereof, and may contain lithium metal and / or lithium metal alloys.

[0036] The cathode active material layer may also optionally include the conductive agent and adhesive as described in the anode active material layer.

[0037] As the cathode current collector, a porous body such as a mesh or a perforated mesh shape can be used, and porous metal plates such as stainless steel, nickel, and aluminum can be used. Furthermore, in order to prevent oxidation, the cathode current collector can be coated with an oxidation-resistant metal or alloy film.

[0038] In one embodiment, an edge insulating layer (not shown) may be further disposed along the edges of the anode layer (11) and the cathode layer (12). The edge insulating layer is located on the solid electrolyte layer (13) and may be formed by laterally adjaculating the edges of the anode active material layer or the cathode active material layer. Therefore, the edge insulating layer may be located in the same layer in the anode layer (11) and the cathode layer (12), respectively.

[0039] The edge insulation layer may contain an insulating material with low ionic conductivity. For example, the insulating material may be a polyolefin such as polyethylene or polypropylene, a polyester such as polyethylene terephthalate (PET), a polyurethane, or a polyimide.

[0040] Furthermore, the edge insulating layer may contain an oxide-based solid electrolyte used in the solid electrolyte layer (13). However, the material contained in the edge insulating layer is not limited to this and may contain various materials.

[0041] The anode layer (11) and cathode layer (12) of the all-solid-state battery (10) can be connected to external electrodes (14, 15). The external electrodes (14, 15) can be connected to the exposed terminals of each current collector of the anode layer (11) and cathode layer (12), thereby becoming the anode and cathode respectively.

[0042] According to one embodiment of the present invention, the anode layer (11), cathode layer (12), and solid electrolyte layer (13) of the all-solid-state battery (10) are formed by each being formed in a plurality of layers and stacked alternately in a plurality of layers to form a battery stack. FIG2 shows a configuration in which the anode layer (11) and cathode layer (12) are arranged alternately and the solid electrolyte layer (13) is arranged therebetween, but the configuration of the anode layer (11), cathode layer (12), and solid electrolyte layer (13) is not limited to that shown in the figure. In one embodiment, a protective layer (not shown) may be formed from an insulating material in the upper and lower sections of the battery stack.

[0043] According to one embodiment of the present invention, the all-solid-state battery (10) may include a housing (16) configured to surround the battery stack. External electrodes (14, 15) may be disposed at both ends of the housing (16).

[0044] The external electrodes (14, 15) may comprise a conductive metal and glass. The conductive metal may be, for example, a conductive metal comprising copper (Cu), nickel (Ni), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb), or an alloy thereof.

[0045] The glass composition contained in the external electrodes (14, 15) may be a mixture of oxides. The glass composition may include, for example, silicon oxide, boron oxide, aluminum oxide, transition metal oxide, alkali metal oxide, alkaline earth metal oxide, or combinations thereof. Here, the transition metal may be selected from one or more of zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni); the alkali metal may be selected from one or more of lithium (Li), sodium (Na), and potassium (K); and the alkaline earth metal may be selected from one or more of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0046] The method for forming the external electrodes (14, 15) is not particularly limited. For example, they can be formed by impregnating the battery stack with a conductive paste containing a conductive metal and glass, or by printing the conductive paste onto the surface of the battery stack using a screen printing or gravure printing method. In addition, various methods can be used, such as coating the surface of the battery stack with a conductive paste or transferring a dried film formed by drying the conductive paste onto the battery stack.

[0047] The housing (16) can protect the battery stack containing the anode layer (11), cathode layer (12) and solid electrolyte layer (13) from being exposed to the outside. In order to protect the internal structure from external moisture, heat, electricity, etc., the housing (16) needs to have moisture permeability, heat resistance, insulation, etc., as well as long-term stability and high resistance to chemical corrosion.

[0048] According to one embodiment of the present invention, an all-solid-state battery (10) can be manufactured by laminating an anode layer (11), a cathode layer (12), a solid electrolyte layer (13), a casing (16), etc., and then sintering them into one piece. In this sintering process, in order to prevent the properties of the electrode layers, etc., each component including the solid electrolyte layer (13) needs to be sintered at a low temperature, for example, below 700°C.

[0049] Thus, the solid electrolyte of the all-solid-state battery (10) according to an embodiment of the present invention needs to have excellent low-temperature characteristics.

[0050] According to an embodiment of the present invention, the solid electrolyte layer (13) contains an oxide-based electrolyte as a solid electrolyte.

[0051] As oxide-based solid electrolytes, there are known sodium superionic conductors (Nasicon type) such as LAGP and garnet type such as LLZO. It is known that through continuous research and development, the ionic conductivity of such oxide-based solid electrolytes has been improved to the level of 10-4 S / cm.

[0052] However, there are limitations to further improving the ionic conductivity using the aforementioned sodium superionic conductor type and garnet type oxide-based solid electrolytes. Furthermore, while sintering these oxide-based solid electrolytes at temperatures above 1000°C can achieve a certain degree of excellent ionic conductivity, as mentioned above, the increased manufacturing costs due to high-temperature sintering are unavoidable. In particular, under high-temperature sintering conditions, it is practically impossible to sinter the solid electrolyte, anode layer, and cathode layer together.

[0053] In one embodiment of the present invention, the sintering temperature is reduced and excellent ionic conductivity is ensured by using a new oxide-based solid electrolyte that overcomes the limitations of such conventional oxide-based solid electrolytes.

[0054] According to an embodiment of the present invention, the solid electrolyte for an all-solid-state battery can be formed from oxides comprising Li, B, Al, Cl and alkaline earth metals. Specifically, the solid electrolyte according to an embodiment of the present invention can comprise Li₂O, B₂O₃, Al₂O₃, LiCl and alkaline earth metal oxides. Here, the alkaline earth metal can be at least one of Ba, Ca, Mg and Sr.

[0055] In solid electrolytes, Li2O can function as a network modifier, providing Li ions to improve ionic conductivity.

[0056] In solid electrolytes, B2O3 itself has strong bonds and small cation size, so it can play the role of a major network forming agent.

[0057] In solid electrolytes, Al2O3 can function as an intermediate. That is, depending on its concentration within the composition, Al2O3 can function as a network forming agent or a network modifying agent. This is due to the high vacancy concentration of Al ions.

[0058] In solid electrolytes, alkaline earth metal oxides can function as intermediates or network modifiers.

[0059] In solid electrolytes, LiCl plays a role in improving ionic conductivity by increasing the number of Li and Cl ions. At this time, the increased Cl ions can move into the network structure as free ions, thereby increasing the lattice constant of the oxide crystal structure. Therefore, the movement path of Li ions in the crystal structure can be ensured to be wider, thereby further improving ionic conductivity.

[0060] In solid electrolytes, B oxides form trigonal and tetrahedral structures centered on B ions, while Al oxides form tetrahedral structures centered on Al ions. The ionic radii of alkaline earth metal ions (X²⁺) are similar to those of Li ions, thus allowing them to substitute for Li ions at Al ion sites. However, the atomic states of alkaline earth metal ions (X²⁺) differ from those of Li ions, leading to a charge imbalance in the crystal lattice. This charge imbalance distorts the positions of surrounding atoms, affecting Li vacancies. The presence of Li vacancies lowers the energy barrier for movement, allowing Li ions to easily move from one position to another. This increases the mobility of Li ions within the crystal lattice, thereby increasing ionic conductivity.

[0061] In one embodiment, preferably, the solid electrolyte may contain 0.4 to 11 mol% of alkaline earth metals. More preferably, the solid electrolyte may contain 0.4 to 10 mol% of alkaline earth metals.

[0062] According to an embodiment of the present invention, the solid electrolyte for an all-solid-state battery may contain 21 to 29 mol% Li2O, 24 to 46 mol% B2O3, 9 to 21 mol% Al2O3 and 16 to 31 mol% LiCl.

[0063] According to an embodiment of the present invention, the solid electrolyte can be manufactured from precursor powders containing Li2CO3, H3BO3, Al2O3, LiCl and alkaline earth metal oxides. Specifically, according to an embodiment of the present invention, the solid electrolyte can be manufactured by the following process.

[0064] (1) Prepare a precursor powder containing Li2CO3, H3BO3, Al2O3, LiCl and alkaline earth metal oxides (alkaline earth metal is at least one of Ba, Ca, Mg and Sr).

[0065] (2)The precursor powder is mixed uniformly by dry or wet mixing.

[0066] (3)The mixture of precursor powders is melted in an aluminum crucible at a temperature of about 900°C or higher.

[0067] (4)The molten material is rapidly cooled to room temperature on the quenching roller.

[0068] (5)Pulverize the cooled melt into microparticles.

[0069] (6) The pulverized material is granulated and sintered at a temperature of about 600°C.

[0070] The solid electrolyte obtained by the above process exhibits an ionic conductivity of approximately 1.1 × 10⁻⁵ S / cm or higher at room temperature. More preferably, the solid electrolyte exhibits an ionic conductivity of 1.2 × 10⁻⁴ S / cm or higher.

[0071] Thus, according to an embodiment of the present invention, the solid electrolyte for an all-solid-state battery is formed from oxides containing Li, B, Al, Cl and alkaline earth metals, thereby enabling sintering at a temperature of approximately 700°C and exhibiting excellent ionic conductivity. Furthermore, since low-temperature sintering is possible, the solid electrolyte layer and the electrode can be sintered simultaneously, thereby simplifying the manufacturing process and improving quality.

[0072] Furthermore, by using the melt quenching method to manufacture the solid electrolyte for an all-solid-state battery according to an embodiment of the present invention, a uniform distribution of dopants and additives can be achieved, thereby improving the quality of the all-solid-state battery and enabling easy mass production on an industrial scale.

[0073] On the other hand, the solid electrolyte according to an embodiment of the present invention has excellent ionic conductivity and non-hygroscopicity. Therefore, even if moisture flows into the all-solid-state battery, the battery performance will not decrease, and stable and excellent performance can be maintained.

[0074] Experimental Example

[0075] Precursor powders containing Li2CO3, H3BO3, Al2O3, LiCl and alkaline earth metal oxides were prepared. At this time, ten kinds of precursor powders were prepared by setting different amounts of Li2CO3, H3BO3, Al2O3, LiCl and XO (X is at least one of Ba, Ca, Mg and Sr).

[0076] To ensure the homogeneity of the solid electrolyte, the precursor powder was thoroughly mixed by ball milling or mechanical mixing. Furthermore, the precursor powder was placed in a crucible, melted at a temperature of approximately 900°C, and the melt was rapidly cooled on a quenching roller. After being pulverized using a planetary ball mill and sieved, micron-sized fine powder was obtained.

[0077] The composition of the fine powder manufactured as described above is shown in Table 1. In Table 1, the composition of XO (mol%) represents the total composition (mol%) of BaO, CaO, MgO and SrO.

[0078] [Table 1] distinguish Composition of solid electrolytes (mol%) Li2O B2O3 Al2O3 LiCl XO Example 1 23.6 45 9.6 16.1 5.7 Example 2 21.4 42.7 9.6 18.2 8.1 Example 3 21.9 37.9 12 18.9 9.3 Example 4 26.9 34.7 14.4 20.2 3.8 Example 5 22.1 31.4 16.6 19.4 10.5 Example 6 28.4 30.2 16.1 22.7 2.6 Example 7 26.7 24.9 16.7 21.7 10 Example 8 24.5 25.5 20.0 30.0 0.5 Comparative Example 1 31.5 41.6 6.5 20.4 - Comparative Example 2 35.0 44.0 5.7 15.0 0.3

[0079] Figure 3 is a graph showing the XRD analysis results of the solid electrolyte powder before sintering according to the embodiments and comparative examples of the present invention. Referring to Figure 3, the XRD graph of the solid electrolyte powder before sintering according to the embodiments of the present invention does not show a crystallization peak. This indicates that the powder before sintering is in an amorphous state, in which it is difficult to form a lithium ion pathway that enables ion diffusion.

[0080] The temperature characteristics measured by differential thermal analysis (DTA) and high temperature microscopy (HTM) for each embodiment and comparative example are described in Table 2.

[0081] [Table 2] distinguish Transfer temperature (Tg, ℃) Crystallization temperature (Tc, ℃) Sintering temperature (T) sint (℃) softening point (T) soft (℃) Half Ball (T) half-ball (℃) Example 1 397 473 426 730 733 Example 2 398 472 436 730 736 Example 3 390 476 451 757 766 Example 4 396 472 456 777 780 Example 5 398 483 468 782 786 Example 6 395 470 480 785 789 Example 7 390 457 426 789 791 Example 8 389 464 441 800 802 Comparative Example 1 390 470 478 805 808 Comparative Example 2 389 475 444 767 790

[0082] Referring to Table 2, all the examples and comparative examples that underwent analysis showed a transfer temperature of 389°C to 398°C and a crystallization temperature of 457°C to 483°C.

[0083] Furthermore, all the examples and comparative examples analyzed showed a low sintering temperature of below 480°C. This indicates that sintering can be performed at a significantly lower temperature compared to conventional oxide-based solid electrolytes sintered at high temperatures above 1,000°C.

[0084] After granulating the powder with the composition of Table 1 above, it is sintered at a temperature of 400°C or higher to produce a solid electrolyte.

[0085] Table 3 shows the measurement results of the ionic conductivity of the solid electrolytes according to the embodiments and comparative examples of the present invention.

[0086] [Table 3] distinguish Ionic conductivity (S / cm) Example 1 1.12×10 -5 Example 2 1.27×10 -4 Example 3 1.34×10 -4 Example 4 2.27×10 -4 Example 5 2.37×10 -5 Example 6 3.75×10 -5 Example 7 1.37×10 -5 Example 8 1.66×10 -4 Comparative Example 1 1.00×10 -5 Comparative Example 2 6.12×10 -6

[0087] Referring to Table 3, it can be confirmed that the solid electrolytes of Examples 1 to 8 exhibit ionic conductivity of 1.12 × 10⁻⁵ S / cm or higher, which is higher than that of the comparative examples, which have ionic conductivity of 1.0 × 10⁻⁵ S / cm or lower. In particular, it can be confirmed that the solid electrolytes of Examples 2 to 4 and 8 have very high ionic conductivity at the level of 10⁻⁴ S / cm.

[0088] Figure 4 is a graph showing the XRD analysis results of the solid electrolytes according to the embodiments and comparative examples of the present invention after sintering. Referring to Figure 4, the XRD graph of the solid electrolyte after sintering shows multiple crystallization peaks. In this crystalline structure, ion flow is smooth, thereby exhibiting excellent ionic conductivity.

[0089] Figure 5 is a graph showing the EIS analysis results of the solid electrolyte powder according to an embodiment of the present invention. As shown in Figure 5, the solid electrolyte powder according to an embodiment of the present invention meets the real impedance axis (x-axis) at an impedance of about 3,700 ohms.

[0090] In this experimental example, the case where the alkaline earth metal is Mg is shown, but the same effect can be obtained for other alkaline earth metal oxides (e.g., Ba, Ca and Sr).

[0091] The above experimental examples confirm that solid electrolytes containing Li₂O, B₂O₃, Al₂O₃, LiCl, and alkaline earth metal oxides exhibit low-temperature characteristics and improved ionic conductivity. In particular, when the overall composition contains 0.4 to 11 mol%, especially 0.4 to 10 mol%, of alkaline earth metal oxides, a significant increase in ionic conductivity can be confirmed.

[0092] The present invention has been described above using specific constituent elements and limited embodiments. However, the foregoing embodiments are only provided to help to understand the present invention more fully. The present invention is not limited thereto. Anyone with ordinary knowledge in the technical field to which the present invention pertains can make various modifications and variations from such description.

[0093] Therefore, the concept of the present invention should not be limited to the previously described embodiments, and is not limited to the scope of the patent application described below. All owners of works that are equivalent to or have equivalent variations of the scope of the patent application are within the scope of the present invention. [Simplified Explanation of the Diagram]

[0018] Figure 1 is a schematic perspective view of an all-solid-state battery.

[0019] Figure 2 is a cross-sectional view of an all-solid-state battery.

[0020] Figure 3 is a graph showing the XRD analysis results of the solid electrolyte powder before sintering according to the embodiments and comparative examples of the present invention.

[0021] Figure 4 is a graph showing the XRD analysis results of the solid electrolytes after sintering according to the embodiments and comparative examples of the present invention.

[0022] Figure 5 is a graph showing the EIS analysis results of the solid electrolyte according to an embodiment of the present invention.

Claims

1. A solid electrolyte for all-solid-state batteries, characterized in that it is formed from an oxide comprising Li, B, Al, Cl and an alkaline earth metal, comprising 21 to 29 mol% Li₂O, 24 to 46 mol% B₂O₃, 9 to 21 mol% Al₂O₃, 16 to 31 mol% LiCl and 0.4 to 11 mol% alkaline earth metal.

2. The solid electrolyte for an all-solid-state battery as described in claim 1, wherein the aforementioned alkaline earth metal is at least one of Ba, Ca, Mg and Sr.

3. The solid electrolyte for all-solid-state batteries as described in claim 1, comprising 0.4 to 10 mol% of the aforementioned alkaline earth metal.

4. The solid electrolyte for all-solid-state batteries as described in claim 1, which is manufactured from precursor powders containing Li2CO3, H3BO3, Al2O3, LiCl and alkaline earth metal oxides.

5. The solid electrolyte for all-solid-state batteries as described in claim 1, having an ionic conductivity of 1.1 × 10⁻⁵ S / cm or higher.

6. An all-solid-state battery, characterized in that it comprises: an anode layer; a cathode layer; and a solid electrolyte layer, wherein the solid electrolyte layer is formed of an oxide comprising Li, B, Al, Cl and an alkaline earth metal, comprising 21 to 29 mol% Li₂O, 24 to 46 mol% B₂O₃, 9 to 21 mol% Al₂O₃, 16 to 31 mol% LiCl and 0.4 to 11 mol% alkaline earth metal.

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