KR20230027461A - Composite solid electrolyte sheet with excellent ion conductivity and manufacturing method of all-solid lithium ion battery using same - Google Patents

Abstract

The present invention relates to a solid electrolyte for an all-solid lithium secondary battery that includes powder having lithium lanthanum zirconium oxide (LLZO) doped with gallium (Ga) and rubidium (Rb) represented by chemical formula 1, wherein the powder has a lattice constant of 12.96620 to 12.97440 Å and a crystal size of 860 to 3,990 Å. A solid electrolyte and a manufacturing method thereof according to the present invention can control the behavior of the lattice constant and the crystal size in a crystal structure forming a particle by controlling a calcination temperature condition (700 to 1200℃).

Description

Composite solid electrolyte sheet with excellent ion conductivity and method for manufacturing an all-solid lithium secondary battery using the same

The present invention relates to a LLZO solid electrolyte doped with gallium and rubidium, a high ionic conductivity solid electrolyte sheet including the same, and a method for manufacturing an all-solid lithium secondary battery using the same, and more particularly, to gallium and rubidium doping in garnet LLZO It relates to a solid electrolyte whose crystal structure is controlled by, a high ionic conductivity solid electrolyte sheet including the same, and a method for manufacturing an all-solid-state lithium secondary battery using the same.

Because lithium secondary batteries have large electrochemical capacity, high operating potential, and excellent charge/discharge cycle characteristics, they are in demand for applications such as portable information terminals, portable electronic devices, small power storage devices for home use, motorcycles, electric vehicles, and hybrid electric vehicles. It is increasing. In accordance with the spread of such uses, there is a demand for improved safety and higher performance of lithium secondary batteries.

As conventional lithium secondary batteries use liquid electrolytes, they are easily ignited when exposed to water in the air, and safety issues have always been raised. These safety issues are becoming more of an issue as electric vehicles become visible.

Accordingly, research on an all-solid-state secondary battery using a solid electrolyte made of an inorganic material, which is a non-combustible material, has recently been actively conducted for the purpose of improving safety. All-solid-state secondary batteries are attracting attention as next-generation secondary batteries from the viewpoints of safety, high energy density, high power, long lifespan, simplification of manufacturing processes, large/compact batteries, and low cost.

An all-solid-state secondary battery is composed of an anode/solid electrolyte layer/cathode, and among them, the solid electrolyte of the solid electrolyte layer requires high ionic conductivity and low electronic conductivity.

Solid electrolytes that satisfy the requirements of a solid electrolyte layer of an all-solid-state secondary battery include sulfide-based and oxide-based solid electrolytes. Among them, the sulfide-based solid electrolyte has problems in that a resistance component is generated by an interfacial reaction with the positive electrode active material or the negative electrode active material, has strong hygroscopicity, and generates hydrogen sulfide (H ₂ S) gas, which is a toxic gas.

Japanese Patent Registration No. 4,779,988 discloses an all-solid lithium secondary battery comprising a sulfide-based solid electrolyte layer having a stacked structure of positive electrode/solid electrolyte layer/negative electrode.

Oxide-based solid electrolytes such as LLTO (Li _3x La _2/(3-x) TiO ₃ ) and LLZO (Li ₇ La ₃ Zr ₂ O ₁₂ ) are widely known. LLZO, known for its excellent potential window properties, is attracting attention as a promising material.

Despite the advantages of the LLZO such as high ionic conductivity, low reactivity with electrode materials, and a wide potential window (Potential Window, 0-6V), it is difficult to set process conditions due to volatilization of lithium (Li) in the sintering process However, its manufacturing process is complex and difficult due to its sinterability, making it difficult to apply in practice. In addition, since there is a large difference in ionic conductivity depending on the crystal structure, it is necessary to develop a technique for controlling the crystal structure of LLZO by adjusting the composition of the starting material, calcination and sintering characteristics, etc.

An object of the present invention is to control the behavior of lattice constant and crystal size in the crystal structure forming particles by controlling the calcination temperature conditions (700 ~ 1200 ℃) LLZO solid electrolyte, It is to provide a method for manufacturing a solid electrolyte sheet including the same and an all-solid-state lithium secondary battery including the same.

According to one aspect of the present invention, a powder having lithium lanthanum zirconium oxide (LLZO) doped with gallium (Ga) and rubidium (Rb) represented by Formula 1 below, wherein the powder has a lattice constant of 12.96620 to 12.97440 Å, and having a crystal size of 860 to 3,990 Å, a solid electrolyte for an all-solid-state lithium secondary battery is provided.

[Formula 1]

Li _x Ga _p La _y Rb _q Zr _z O ₁₂ (5≤x≤9, 0<p≤1, 0<q≤1, 2≤y≤4, 1≤z≤3)

The powder may have a lattice constant of 12.97320 to 12.97440 Å and a crystal size of 860 to 1,550 Å.

The powder may have a lattice constant of 12.96780 to 12.96910 Å and a crystal size of 2,220 to 3,990 Å.

The powder may have a particle size of 3 to 10 μm.

The ionic conductivity of the composite solid electrolyte sheet including a solid electrolyte having a lattice constant of 12.97320 to 12.97440 Å and a crystal size of 860 to 1,550 Å and a binder is 1.80 x 10 ^-8 to 2.40 x 10 ^-8 S / cm at 25 ° C. And, 2.65 x 10 ^-6 to 6.20 x 10 ^-6 S / cm at 45 ℃, it may be 2.80 x 10 ^-4 to 4.55 x 10 ^-4 S / cm at 70 ℃.

The ionic conductivity of the composite solid electrolyte sheet including a solid electrolyte having a lattice constant of 12.96780 to 12.96910 Å and a crystal size of 2,220 to 3,990 Å and a binder is 2.05 x 10 ^-8 to 1.55 x 10 ^-6 S / cm at 25 ° C. And, 2.60 x 10 ^-6 to 6.70 x 10 ^-5 S / cm at 45 ° C, and 5.10 x 10 ^-4 to 7.45 x 10 ^-4 S / cm at 70 ° C.

According to another aspect of the present invention, a positive electrode including a first solid electrolyte; a composite solid electrolyte sheet formed on the anode and including a second solid electrolyte; and a cathode formed on the composite solid electrolyte sheet, wherein the first and second solid electrolytes are lithium lanthanum zirconium oxide (LLZO) doped with gallium (Ga) and rubidium (Rb) represented by Formula 1 below, respectively. ), wherein the powder has a lattice constant of 12.96620 to 12.97440 Å and a crystal size of 860 to 3,990 Å.

[Formula 1]

Li _x Ga _p La _y Rb _q Zr _z O ₁₂ (5≤x≤9, 0<p≤1, 0<q≤1, 2≤y≤4, 1≤z≤3)

According to another aspect of the present invention, (a) a metal precursor aqueous solution containing a lanthanum (La) precursor, a zirconium (Zr) precursor, a gallium (Ga) precursor, and a rubidium (Rb) precursor, a complexing agent, and a pH adjusting agent preparing a solid electrolyte precursor slurry by co-precipitating the mixed solution in a Taylor vortex state; (b) preparing a solid electrolyte precursor by washing and drying the solid electrolyte precursor slurry; (c) preparing a mixture by mixing the solid electrolyte precursor with a lithium source; And (d) preparing a powder having lithium lanthanum zirconium oxide (LLZO) doped with gallium (Ga) and rubidium (Rb) represented by Formula 1 below by calcining the mixture at a temperature of 700 to 1,200 ° C. Including, the powder has a lattice constant of 12.96620 to 12.97440 Å, and a crystal size of 860 to 3,990 Å, a method for producing a solid electrolyte is provided.

[Formula 1]

Li _x Ga _p La _y Rb _q Zr _z O ₁₂ (5≤x≤9, 0<p≤1, 0<q≤1, 2≤y≤4, 1≤z≤3)

In step (d), when the mixture is calcined at a temperature of 800 to 900° C., the crystal size of the powder may decrease as the temperature increases.

In step (d), when the mixture is calcined at a temperature of 800 to 900 ° C, the crystal size of the powder may be 860 to 1,550 Å.

In step (d), when the mixture is calcined at a temperature of 1,000 to 1,100 ° C, the crystal size of the powder may increase as the temperature increases.

In step (d), when the mixture is calcined at a temperature of 1,000 to 1,100 °C, the crystal size of the powder may be 2,200 to 3,990 Å.

In step (d), when the mixture is calcined at a temperature of 1,000 to 1,100° C., grain boundary resistance of the powder may decrease as the temperature increases.

In step (d), when the mixture is calcined at a temperature of 700 to 900° C., the powder may form secondary particles by bonding between primary particles or local sintering.

In step (d), when the mixture is calcined at a temperature of 1,000 to 1,200 ° C, the powder may form high-density single particles with a lattice size grown by sintering between primary particles.

The lanthanum precursor is lanthanum nitrate (La(NO ₃ ) ₃ ) or a hydrate thereof, the zirconium precursor is zirconium hydrochloride (ZrOCl ₂ ) or a hydrate thereof, and the gallium precursor is gallium nitrate (Ga(NO ₃ ) ₃ ) or a hydrate thereof. hydrate, and the rubidium precursor may be rubidium nitrate (RbNO ₃ ) or a hydrate thereof.

According to another aspect of the present invention, (1) manufacturing a positive electrode including a solid electrolyte according to the manufacturing method; (2) manufacturing a composite solid electrolyte sheet including the solid electrolyte according to the manufacturing method; (3) manufacturing a laminate by laminating the positive electrode and the composite solid electrolyte sheet; and (4) disposing a negative electrode on the composite solid electrolyte sheet of the laminate.

The solid electrolyte and its manufacturing method of the present invention can control the behavior of lattice constant and crystal size in the crystal structure forming particles by adjusting the calcination temperature conditions (700 ~ 1200 ℃). There is an effect.

1 is a flowchart of a method for manufacturing a solid electrolyte according to the present invention.
2 is a schematic diagram of a Kuett Taylor vortex reactor.
Figure 3 is the XRD results of Ga, Rb-LLZO solid electrolytes according to Examples 1-1 to 1-6, Figure 4 is the XRD results of Ga, Rb-LLZO solid electrolytes according to Examples 1-1 to 1-6 This is the result of Rietveld analysis for .
5a to 5f are SEM analysis images of Ga,Rb-LLZO solid electrolytes according to Examples 1-1 to 1-6.
6 is an ion conductivity graph of composite solid electrolyte sheets according to Examples 2-1 to 2-6.
7 is a graph of LSV characteristics of composite solid electrolyte sheets according to Examples 2-3 and 2-5.
8 is an initial charge/discharge curve of an all-solid-state lithium secondary battery according to Device Examples 1 to 3;
9 shows charge/discharge cycles and coulombic efficiencies of all-solid-state lithium secondary batteries according to Device Examples 1 to 3.
10 is an evaluation result of rate characteristics of all-solid-state lithium secondary batteries according to Device Examples 1 to 3.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

However, the following description is not intended to limit the present invention to specific embodiments, and in describing the present invention, if it is determined that the detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted. .

Terms used herein are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, operation, component, or combination thereof described in the specification, but one or more other features or It should be understood that the presence or addition of numbers, steps, operations, elements, or combinations thereof is not precluded. However, this is presented as an example, and the present invention is not limited thereby, and the present invention is only defined by the scope of the claims to be described later.

Hereinafter, a solid electrolyte and an all-solid lithium secondary battery including the solid electrolyte according to the present invention will be described in detail.

The present invention includes a powder having lithium lanthanum zirconium oxide (LLZO) doped with gallium (Ga) and rubidium (Rb) represented by Formula 1 below, wherein the powder has a lattice constant of 12.96620 to 12.97440 Å, It provides a solid electrolyte for an all-solid-state lithium secondary battery having a crystal size of 860 to 3,990 Å.

[Formula 1]

Li _x Ga _p La _y Rb _q Zr _z O ₁₂ (5≤x≤9, 0<p≤1, 0<q≤1, 2≤y≤4, 1≤z≤3)

The powder may have a lattice constant of 12.97320 to 12.97440 Å and a crystal size of 860 to 1,550 Å.

The powder may have a lattice constant of 12.96780 to 12.96910 Å and a crystal size of 2,220 to 3,990 Å.

The powder may have a particle size of 3 to 10 μm.

The ionic conductivity of the composite solid electrolyte sheet including a solid electrolyte having a lattice constant of 12.97320 to 12.97440 Å and a crystal size of 860 to 1,550 Å and a binder is 1.80 x 10 ^-8 to 2.40 x 10 ^-8 S / cm at 25 ° C. And, 2.65 x 10 ^-6 to 6.20 x 10 ^-6 S / cm at 45 ℃, it may be 2.80 x 10 ^-4 to 4.55 x 10 ^-4 S / cm at 70 ℃.

The ionic conductivity of the composite solid electrolyte sheet including a solid electrolyte having a lattice constant of 12.96780 to 12.96910 Å and a crystal size of 2,220 to 3,990 Å and a binder is 2.05 x 10 ^-8 to 1.55 x 10 ^-6 S / cm at 25 ° C. And, 2.60 x 10 ^-6 to 6.70 x 10 ^-5 S / cm at 45 ° C, and 5.10 x 10 ^-4 to 7.45 x 10 ^-4 S / cm at 70 ° C.

In addition, the present invention is a positive electrode comprising a first solid electrolyte; a composite solid electrolyte sheet formed on the anode and including a second solid electrolyte; and a cathode formed on the composite solid electrolyte sheet, wherein the first and second solid electrolytes are lithium lanthanum zirconium oxide (LLZO) doped with gallium (Ga) and rubidium (Rb) represented by Formula 1 below, respectively. ), wherein the powder has a lattice constant of 12.96620 to 12.97440 Å and a crystal size of 860 to 3,990 Å.

[Formula 1]

Li _x Ga _p La _y Rb _q Zr _z O ₁₂ (5≤x≤9, 0<p≤1, 0<q≤1, 2≤y≤4, 1≤z≤3)

The first solid electrolyte may have a lattice constant of 12.97320 to 12.97440 Å and a crystal size of 860 to 1,550 Å.

The second solid electrolyte may have a lattice constant of 12.96780 to 12.96910 Å and a crystal size of 2,220 to 3,990 Å.

The positive electrode may further include a positive electrode active material, a conductive material, and a first binder.

The cathode active material is lithium nickel cobalt aluminum oxide (NCA), lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), lithium nickel cobalt manganese oxide ( LiNiCoMnO ₂ ) and at least one selected from the group consisting of lithium nickel cobalt manganese oxide (NCM).

The conductive material may include at least one selected from the group consisting of carbon black, acetylene black, ketjen black, carbon fiber, carbon nanotube, and graphene.

The composite solid electrolyte sheet may further include a second binder.

The first and second binders are polyethyleneoxide, polyethyleneglycol, polyacrylonitrile, polyvinylchloride, polymethylmethacrylate, polypropyleneoxide, respectively. ), polydimethylsiloxane, polyvinylidenefluoride, polyvinylidenecarbonate, and polyvinylpyrrolidinone.

Each of the positive electrode and the composite solid electrolyte sheet may further include a lithium salt.

The lithium salt is lithium perchlorate (LiClO ₄ ), lithium bis(fluorosulfonyl)imide (LiFSI), lithium triflate (LiCF ₃ SO ₃ ), lithium hexafluorophosphate (LiPF ₆ ), At least one selected from the group consisting of lithium tetrafluoroborate (LiBF ₄ ) and lithium trifluoromethanesulfonylimide (LiN(CF ₃ SO ₂ ) ₂ ) may be included.

1 is a flowchart of a method for manufacturing a solid electrolyte powder according to the present invention. Hereinafter, a method for manufacturing a solid electrolyte powder and a method for manufacturing an all-solid-state lithium secondary battery including the solid electrolyte powder according to the present invention will be described in detail with reference to FIG. 1 .

First, a mixed solution in which an aqueous metal precursor solution containing a lanthanum (La) precursor, a zirconium (Zr) precursor, a gallium (Ga) precursor, and a rubidium (Rb) precursor, a complexing agent, and a pH adjuster is mixed is coprecipitated in a Taylor vortex state reacted to prepare a solid electrolyte precursor slurry (step a).

Step (a) may be performed in a Kuett Taylor vortex reactor.

The co-precipitation reaction of step (a) may be carried out for 1 to 5 hours.

When the co-precipitation reaction is performed for less than 1 hour, the reaction of the LLZO precursor is not properly performed, which is not preferable, and when the coprecipitation reaction is performed for more than 5 hours, the size of the precursor grows excessively, which is not preferable.

The lanthanum precursor may be lanthanum nitrate (La(NO ₃ ) ₃ ) or a hydrate thereof, the zirconium precursor may be zirconium hydrochloride (ZrOCl ₂ ) or a hydrate thereof, and the gallium precursor may be gallium nitrate (Ga(NO ₃ ) ₃ ) or a hydrate thereof, and the rubidium precursor may be rubidium nitrate (RbNO ₃ ) or a hydrate thereof. Here, x is any one of integers from 0 to 15, respectively.

The complexing agent may be ammonium hydroxide (NH ₄ ·OH) or sodium hydroxide.

The pH adjusting agent may adjust the pH of the mixed solution to 10 to 12, and may include sodium hydroxide (NaOH), ammonia, and the like, but is not limited thereto. Any other pH adjuster capable of adjusting the pH of the mixed solution without affecting the physical properties of the ion conductive solid oxide is possible.

2 is a schematic diagram of a Taylor vortex reactor.

Referring to FIG. 2 , a Cuett-Taylor vortex reactor capable of performing a Cuett-Taylor vortex reaction includes an outer fixed cylinder and an inner rotating cylinder rotating therein. The inner rotating cylinder has an axis of rotation coincident with the longitudinal axis of the outer fixed cylinder. The inner rotating cylinder and the outer fixed cylinder are installed to be spaced apart from each other at a predetermined interval, and a fluid passage through which the reaction liquid flows is formed between the inner rotating cylinder and the outer fixed cylinder. When the inner rotating cylinder rotates, the fluid located on the side of the inner rotating cylinder in the fluid passage has a tendency to go out in the direction of the outer fixed cylinder by the centrifugal force. A vortex of Lee pair arrangement is formed. This is called a Taylor or Kuett Taylor vortex. The Kuett-Taylor vortex promotes the co-precipitation reaction and thus can produce precursors more advantageously than conventional co-precipitation reactors.

At this time, the Couette-Taylor reactor can distinguish the characteristics of the fluid flow using the Taylor number (Ta), which is a dimensionless variable, and can indicate the definition of the corresponding region for each characteristic. The Taylor number (Ta) is represented by a function of the Reynolds number (Re) and is expressed by Equation 1 as follows.

[Equation 1]

In Equation 1, w means the angular velocity of the inner cylinder, r _i is the radius of the inner cylinder, d is the parallel distance between the two cylinders, and v is the kinematic viscosity. In general, the value of the Taylor number (Ta) is adjusted using the number of revolutions per minute (RPM) expressed as the angular velocity of the inner cylinder. In general, when a fluid flows between two flat plates, a Couette flow occurs due to shear stress, and similarly, a Couette flow also occurs between two cylinders at low RPM. However, when the RPM of the inner cylinder exceeds a certain threshold value, the Couette flow becomes a new steady-state Couette-Taylor flow, and Taylor vortices, which were not seen in the Couette flow, occur. The Taylor vortex consists of two vortices as a pair, and has the feature of line symmetry and is located in the toroidal direction. Therefore, there are vortices rotating in the counterclockwise direction on both sides of the vortex rotating in the clockwise direction, so that each vortex affects each other. When the RPM of a certain size is increased in the Couette-Taylor flow, it is transformed into a new flow due to the increase in instability of the Taylor vortex, and at this time, the Taylor vortex has an azimuthal wavenumber. This flow is called Wavy vortex flow, and the mixing effect at this time can be greater than that of Couette-Taylor flow.

Next, the solid electrolyte precursor slurry is washed and dried to prepare a solid electrolyte precursor (step b).

Next, a mixture is prepared by mixing the solid electrolyte precursor with a lithium source (step c).

The lithium content of the lithium source may be excessively added in consideration of the amount of lithium evaporated during calcination or sintering.

The lithium source may be at least one selected from the group consisting of lithium hydroxide (LiOH) or its hydrate, LiOH, LiNO ₃ , and LiCO ₃ .

Next, the mixture is calcined at a temperature of 700 to 1,200 ° C. to prepare a powder having lithium lanthanum zirconium oxide (LLZO) doped with gallium (Ga) and rubidium (Rb) represented by Formula 1 below (step d) .

[Formula 1]

Li _x Ga _p La _y Rb _q Zr _z O ₁₂ (5≤x≤9, 0<p≤1, 0<q≤1, 2≤y≤4, 1≤z≤3)

The lithium lanthanum zirconium oxide doped with gallium and rubidium may be represented by Chemical Formula 2 below.

[Formula 2]

Li _(7-3p) Ga _p La _3-q Rb _q Zr ₂ O ₁₂ (0<p≤1, 0<q≤1)

In step (d), when the mixture is calcined at a temperature of 800 to 900° C., the crystal size of the powder may decrease as the temperature increases.

In step (d), when the mixture is calcined at a temperature of 800 to 900 ° C, the crystal size of the powder may be 860 to 1,550 Å, preferably 866 to 1539 Å.

In step (d), when the mixture is calcined at a temperature of 1,000 to 1,100 ° C, the crystal size of the powder may increase as the temperature increases.

In step (d), when the mixture is calcined at a temperature of 1,000 to 1,100 ° C, the crystal size of the powder may be 2,200 to 3,990 Å, preferably 2,231 to 3,988 Å.

In step (d), when the mixture is calcined at a temperature of 1,000 to 1,100° C., grain boundary resistance of the powder may decrease as the temperature increases.

In step (d), when the mixture is calcined at a temperature of 700 to 900 ° C., the powder may form secondary particles by bonding between primary particles or local sintering.

In step (d), when the mixture is calcined at a temperature of 1,000 to 1,200 ° C, the powder may form high-density single particles with a lattice size grown by sintering between primary particles.

The calcination may be performed for 1 to 12 hours, preferably for 1 to 9 hours, and more preferably for 1 to 7 hours. However, the calcination time is not necessarily limited thereto and may vary depending on the calcination temperature.

The lithium lanthanum zirconium oxide doped with gallium and rubidium may include at least one structure selected from the group consisting of a cubic structure and a tetragonal structure, and preferably may include a single-phase cubic structure. there is.

In addition, structurally, the cubic structure is advantageous in terms of ionic conductivity, and the ion conductivity may be lowered in the case of the tetragonal structure.

In addition, the present invention includes (1) preparing a positive electrode including a solid electrolyte according to the manufacturing method; (2) preparing a composite solid electrolyte sheet including the solid electrolyte according to the manufacturing method; (3) manufacturing a laminate by laminating the positive electrode and the composite solid electrolyte sheet; and (4) disposing a negative electrode on the solid electrolyte layer of the laminate.

The negative electrode may include lithium metal.

The composite solid electrolyte sheet is prepared by applying LLZO powder co-doped with Ga and Rb calcined in the range of 700-1200 ° C., and the ionic conductivity is measured at 25 ° C. 10 ^-8 to 1.52 x 10 ^-6 S/cm, and when measured at 45°C, may be 2.65 x 10 ^-6 to 6.69 x 10 ^-5 S/cm.

In addition, the ionic conductivity of the composite solid electrolyte sheet to which the powder calcined at 1,100 to 1,200 ° C, where the crystal size is largest is formed, is 1.24 x 10 ^-7 to 1.52 x 10 ^-6 S / cm at 25 ° C, and 2.65 at 45 ° C x 10 ^-5 to 6.69 x 10 ^-5 S/cm.

In addition, when the ionic conductivity of the composite solid electrolyte sheet to which the calcined powder is applied in the range of 700 to 1200 ° C is measured at 70 ° C, the ionic conductivity may be 2.43 x 10 ^-4 to 8.60 x 10 ^-4 S / cm.

[Example]

Hereinafter, a preferred embodiment of the present invention will be described. However, this is for illustrative purposes and the scope of the present invention is not limited thereby.

[Preparation of solid electrolyte (Ga, Rb-LLZO) doped with gallium (0.2 mole) and rubidium (0.05 mole)]

Example 1-1: Ga, Rb-LLZO calcined at 700 ° C

Starting materials lanthanum nitrate (La(NO ₃ ) ₃ .xH ₂ O), zirconium hydrochloride (ZrOCl ₂ .xH ₂ O), gallium nitrate (Ga(NO ₃ ) ₃ .xH ₂ O) and rubidium nitrate (RbNO ₃ ) were dissolved in distilled water so that the molar ratio of their metal elements, La:Zr:Ga:Rb, was 2.95:2:0.2:0.05 to prepare a starting material solution having a starting material concentration of 1 molar. Here, x is any one of integers from 0 to 15, respectively.

Referring to FIG. 2, a solid electrolyte was prepared using a Kuett Taylor vortex reactor. The Kuett Taylor vortex reactor includes a solution injection part (1), a temperature control solution discharge part (2), a temperature control solution injection part (3), a reaction solution drain part (4), a reactant (slurry type) discharge part (5) , It includes a stirring bar 6, a solution reaction unit 7, and a reaction solution temperature control unit 8. The starting material solution, 160 parts by weight of ammonia water (complexing agent) based on 100 parts by weight of the starting material solution, and an appropriate amount of sodium hydroxide solution were added through the injection part (1) of the Kuett Taylor vortex reactor to adjust the pH to 11 The mixed solution was co-precipitated at a reaction temperature of 25° C., a reaction time of 4 hr, and a stirring speed of the stirring bar at 1000 rpm, and the precursor slurry in the form of a liquid slurry was discharged through the discharge unit 5.

After washing the precursor slurry with purified water, it was dried for 24 hours. A mixture was prepared by adding excess LiOH·H ₂ O to the dried precursor and mixing with a ball mill. The LiOH·H ₂ O content of the mixture was added so that the Li content in LiOH·H ₂ O was 103 parts by weight (excess of 3 wt%) based on 100 parts by weight of Li in the resulting solid electrolyte. The mixture was calcined at 700° C. for 2 hours to prepare a Ga,Rb-LLZO (Li _6.5 Ga _0.2 La _2.95 Rb _0.05 Zr ₂ O ₁₂ ) solid electrolyte powder.

Example 1-2: Ga, Rb-LLZO calcined at 800 ° C

Ga, Rb-LLZO (Li _6.5 Ga _0.2 La _2.95 Rb _0.05 Zr ₂ O ₁₂ ) A solid electrolyte powder was prepared.

Example 1-3: Ga,Rb-LLZO calcined at 900 °C

Ga,Rb-LLZO (Li _6.5 Ga _0.2 La _2.95 Rb _0.05 Zr ₂ O ₁₂ ) A solid electrolyte powder was prepared.

Example 1-4: Ga,Rb-LLZO calcined at 1,000 °C

Ga, Rb-LLZO (Li _6.5 Ga _0.2 La _2.95 Rb _0.05 Zr ₂ O ₁₂ ) A solid electrolyte powder was prepared.

Example 1-5: Ga,Rb-LLZO calcined at 1,100 °C

Ga, Rb-LLZO (Li _6.5 Ga _0.2 La _2.95 Rb _0.05 Zr ₂ O ₁₂ ) A solid electrolyte powder was prepared.

Example 1-6: Ga,Rb-LLZO calcined at 1,200 °C

Ga, Rb-LLZO (Li _6.5 Ga _0.2 La _2.95 Rb _0.05 Zr ₂ O ₁₂ ) A solid electrolyte powder was prepared.

[Manufacture of composite solid electrolyte sheet]

Example 2-1

A mixture was prepared so that the weight ratio of the Ga,Rb-LLZO solid electrolyte powder prepared according to Example 1-1 and the PEO binder was 70:30. That is, a mixture was prepared by mixing 42.86 parts by weight of a polyethylene oxide (PEO) binder based on 100 parts by weight of Ga,Rb-LLZO prepared according to Example 1-1. At this time, the PEO binder includes PEO (molecular weight 200,000), LiClO ₄ and LiFSi (lithium salt), and the molar ratio of the PEO and the lithium salt is [EO]: [LiClO ₄ ]: [LiFSi] = 13: 0.8: 0.2 made this happen.

Specifically, first, after weighing the Ga, Rb-LLZO and PEO binder prepared according to Example 1-1 at the above weight ratio, mixing for 5 minutes at 1,800 rpm using a thinky mixer 3 times The slurry was prepared by repetition. The slurry is cast on a PET (polyethylene terephthalate) film coated with silicon (Si) on one side, and repeated 1 to 2 times at a pressure of 1 to 2 Mpa to have a rolling rate of 20% of the initial thickness using a roll press. A composite solid electrolyte sheet having a thickness of 120 μm was prepared by performing a rolling process.

Example 2-2

Except for using the Ga,Rb-LLZO solid electrolyte prepared according to Example 1-2 instead of using the Ga,Rb-LLZO solid electrolyte prepared according to Example 1-1 in Example 2-1 A composite solid electrolyte sheet was prepared in the same manner as in Example 2-1.

Example 2-3

Except for using the Ga,Rb-LLZO solid electrolyte prepared according to Example 1-3 instead of using the Ga,Rb-LLZO solid electrolyte prepared according to Example 1-1 in Example 2-1 A composite solid electrolyte sheet was prepared in the same manner as in Example 2-1.

Example 2-4

Except for using the Ga,Rb-LLZO solid electrolyte prepared according to Example 1-4 instead of using the Ga,Rb-LLZO solid electrolyte prepared according to Example 1-1 in Example 2-1 A composite solid electrolyte sheet was prepared in the same manner as in Example 2-1.

Example 2-5

Except for using the Ga,Rb-LLZO solid electrolyte prepared according to Example 1-5 instead of using the Ga,Rb-LLZO solid electrolyte prepared according to Example 1-1 in Example 2-1 A composite solid electrolyte sheet was prepared in the same manner as in Example 2-1.

Example 2-6

Except for using the Ga,Rb-LLZO solid electrolyte prepared according to Example 1-6 instead of using the Ga,Rb-LLZO solid electrolyte prepared according to Example 1-1 in Example 2-1 A composite solid electrolyte sheet was prepared in the same manner as in Example 2-1.

[Manufacture of anode]

Example 3-1: Anode containing Ga-Rb LLZO powder calcined at 900 ° C

A mixture was prepared such that the weight ratio of the NCM-424 cathode active material, the Ga,Rb-LLZO solid electrolyte powder according to Examples 1-3, the conductive material, and the binder was 55:5:10:30. That is, based on 100 parts by weight of the NCM-424 cathode active material, 9.09 parts by weight of the Ga,Rb-LLZO solid electrolyte powder according to Examples 1-3, 18.18 parts by weight of the conductive material Super-P, and 54.55 parts by weight of the PEO binder were mixed to prepare a mixture. did At this time, the PEO binder includes PEO (Mn = 600K, Sigma-Aldrich) and LiClO ₄ (99.99%, Sigma-Aldrich) and LiFSi (99%, ENCHEM), and the PEO and the lithium salt (LiClO ₄ and LiFSi ) was set to a molar ratio of [EO]: [LiClO ₄ ]: [LiFSi] = 13: 0.8: 0.2, and ACN was mixed to adjust the appropriate viscosity.

Specifically, first, NCM-424 cathode active material, Ga,Rb-LLZO solid electrolyte powder according to Examples 1-3, and Super-p were weighed in the above weight ratio, and then mixed for 30 minutes using a mortar and pestle to obtain a mixed powder manufactured. The mixed powder was transferred to a container dedicated to a thinky mixer, and then mixed with the PEO binder at the above weight ratio, mounted in a mixer, and mixed once at 1,500 rpm for 5 minutes to prepare a mixture. Next, acetonitrile (ACN) was mixed with the mixture to adjust the viscosity to an appropriate level, and a 2 mm zircon ball was added and mixed at 1,500 rpm for 5 minutes three times to prepare a slurry. The slurry was cast on aluminum foil, dried in a vacuum, and electrode calendered by roll milling at 60° C. to prepare a positive electrode having a loading amount of about 4 mg/cm ² .

Example 3-2: Anode containing Ga-Rb LLZO powder calcined at 1100 ° C

Examples except for using the Ga,Rb-LLZO solid electrolyte powder according to Example 1-5 instead of using the Ga,Rb-LLZO solid electrolyte powder according to Example 1-3 in Example 3-1 A positive electrode was prepared in the same manner as in 3-1.

[Production of All-Solid Lithium Secondary Battery]

Device Example 1

The positive electrode manufactured according to Example 3-1 and the solid electrolyte sheet manufactured according to Example 2-3 were punched into Ø14 and Ø16 sizes, respectively, and then stacked. Next, while heating at about 60°C, a laminate was prepared by pressing at 0.3 MPa for 0.5 minutes. A negative electrode containing 200 μm lithium metal was placed on the solid electrolyte sheet of the laminate, heated to about 60° C. and pressurized at 0.3 MPa for 0.5 minutes to prepare an all-solid lithium secondary battery with a 2032 standard coin cell.

Device Example 2

In Device Example 1, instead of using the positive electrode manufactured according to Example 3-1 and the solid electrolyte sheet manufactured according to Example 2-3, the positive electrode manufactured according to Example 3-2 and the solid electrolyte sheet manufactured according to Example 2-5 An all-solid lithium secondary battery was manufactured in the same manner as in Device Example 1, except for using the solid electrolyte sheet prepared according to the method.

Device Example 3

Device Example 1 was fabricated in the same manner as in Device Example 1, except that a solid electrolyte sheet prepared according to Example 2-5 was used instead of the solid electrolyte sheet prepared according to Example 2-3. A solid lithium secondary battery was prepared.

The configuration of the all-solid-state lithium secondary battery according to Device Examples 1 to 3 is shown in Table 1 below.

anode Complex solid electrolyte sheet cathode cathode active material solid electrolyte bookbinder conductive material solid electrolyte bookbinder Device Example 1 NCM-424 Example 1-3
(calcined at 900℃) PEO Super-P Example 1-3
(calcined at 900℃) PEO lithium metal Device Example 2 Example 1-5
(calcined at 1100℃) Example 1-5
(calcined at 1100℃) Device Example 3 Examples 1-3
(calcined at 900℃) Example 1-5
(calcined at 1100℃)

[Test Example]

Test Example 1: XRD analysis of solid electrolyte by calcination temperature (700 ~ 1200 ℃)

Figure 3 is the XRD results of Ga, Rb-LLZO solid electrolytes according to Examples 1-1 to 1-6, Figure 4 is the XRD results of Ga, Rb-LLZO solid electrolytes according to Examples 1-1 to 1-6 This is the result of Rietveld analysis for .

Referring to FIG. 3, the XRD peak patterns of all of the Ga,Rb-LLZO solid electrolytes according to Examples 1-1 to 1-6 are very similar in appearance and have a typical cubic structure. However, some LZO impurity peaks were observed in Example 1-1 (calcination at 700 ° C), and no impurity peaks were observed in the calcination temperature conditions of 800 ° C or higher (Examples 1-2 to 1-6). In addition, in terms of peak intensity, Example 1-2 (calcination at 800 ° C) has the highest pattern, and the Miller index (112) (024) (224) peaks tend to increase more. However, in the case of Example 1-3 in which the calcination temperature was increased to 900 ° C, the intensity of the peak rapidly decreased, and at the calcination temperature of 1000 ° C or higher (Examples 1-4 to 1-6), an almost similar peak pattern was observed. .

In addition, referring to FIG. 4, the lattice constant for each calcination temperature (700 to 1200 ° C.) was 12.96622 to 12.97438 Å and the crystal size was 866 to 3988 Å. The lattice constant increased from 12.96622 Å at 700 ° C to 12.97438 Å when the calcination temperature was increased to 800 ° C, and decreased again to 12.96 Å at higher temperatures. It represents a lattice constant similar to the condition. In contrast, the crystal size decreased in proportion to the calcination temperature, decreasing to 2018 Å at 700 ° C and 866 Å at 900 ° C. However, at temperatures above 900 ° C, the crystal size increased again, showed a maximum value of 3988 Å at 1100 ° C, and decreased again to 3496 Å at 1200 ° C. Through this, in the calcination temperature range of 800-900 ℃, as the temperature increases, the lattice constant is maintained relatively high in the range of 12.97Å, but the crystal size decreases, and in the calcination temperature range of 1000-1100 ℃, the lattice constant is maintained as low as 12.96Å, and the crystal It was found that it showed a peculiar behavior with a rapid increase in size.

Conventional Ga-doped LLZO materials have a lattice constant of about 12.96 to 13.00 Å, and ionic conductivity tends to increase in the 12.96 Å section where the lattice constant is small, and the crystal size is mostly kept below 600 Å. That is, there was a limit to controlling the ionic conduction resistance of the grain boundary because the crystal size was kept almost constant and low. On the other hand, the lattice constant of the solid electrolyte powder according to the calcination temperature of the present invention is maintained as low as 12.96905 Å, and the crystal size increases by about 4 times or more to a maximum of 3988 Å. It is judged that the grain boundary (GB) resistance will greatly decrease do.

In addition, the present invention is a solid electrolyte (Li _6.5 Ga _0.2 La _2.95 Rb _0.05 Zr ₂ O ₁₂ ) doped with 0.2 mol of Ga and 0.05 mol of Rb, and the lithium content is 6.5, and the precursor prepared by Taylor reaction (co-precipitation) is only Despite the calcination treatment for 2 hours, the conditions for maintaining the optimal grain size constant and crystal size of the cubic crystal structure were secured, and a stable crystal structure was confirmed in a wide calcination temperature range of 800-1,200 ℃.

Test Example 2: SEM analysis of solid electrolyte by calcination temperature (700 ~ 1200 ℃)

5a to 5f are SEM analysis images of Ga,Rb-LLZO solid electrolytes according to Examples 1-1 to 1-6. The Ga,Rb-LLZO solid electrolyte powders according to Examples 1-1 to 1-6 were photographed at magnifications of 2,000 and 15,000, respectively.

5a and 5f, in the case of the solid electrolytes (calcined at 700, 800, and 900° C.) according to Examples 1-1 to 1-3, spherical primary particles of 1 to 2 μm are combined to form 2 μm of 4 to 10 μm. Tea particles were formed. On the other hand, in the case of the solid electrolytes (calcination at 1000, 1100, and 1200 ° C) according to Examples 1-4 to 1-6, it was confirmed that the primary particles grew and sintered high-density single particles of 3 to 10 μm were formed. In particular, when calcined at a temperature of 1000 ° C. or higher, it was found that the primary particles gradually disappeared and spherical powder, which is a high-density secondary particle, was formed. However, at a temperature of 1200 ° C., the calcination temperature was too excessive, and it was confirmed that acicular particles were formed during grinding. In contrast, at 1100 ° C., it was confirmed that spherical high-density powder of about 3 μm was uniformly formed.

Therefore, when the Ga, Rb-LLZO solid electrolyte is calcined at 900 ° C or less, fine powder by primary particles has an agglomerated structure, so it is easily crushed and dispersed into fine particles in the process of manufacturing a composite solid electrolyte sheet by slurry mixing As an advantage, it was possible to overcome the disadvantage of the low crystal size of these fine particles themselves. On the other hand, in the case of the Ga, Rb-LLZO solid electrolyte powder calcined at 1100 ° C, the particle size is relatively increased and the specific surface area is relatively reduced because it is manufactured at high density. The micronization reaction of the particles is small, and as a result, the content of the polymer (binder) relatively required for controlling the interface of the powder can be reduced, thereby increasing the ionic conductivity of the solid electrolyte layer by controlling the uniformity and crystal size of the particles. There are advantages to being able to That is, since the Ga,Rb-LLZO solid electrolyte material according to the present invention has different particle size control or crystal size control depending on the calcination temperature, the effect shown when applied to a composite solid electrolyte sheet and an all-solid lithium secondary battery using these characteristics research is needed on

Test Example 3: Analysis of Ion Conductivity Characteristics of Composite Solid Electrolyte Sheet Containing Ga, Rb-LLZO Solid Electrolyte Powder by Calcination Temperature

6 is a graph of ion conductivity of composite solid electrolyte sheets according to Examples 2-1 to 2-6, and the results are shown in Table 2 below.

temperature Ionic Conductivity (S/cm) Example 2-1 Example 2-2 Example 2-3 Example 2-4 Example 2-5 Example 2-6 70℃ 2.43 x 10 ^-4 2.83 x 10 ^-4 4.50 x 10 ^-4 5.14 x 10 ^-4 7.39 x 10 ^-4 8.60 x 10 ^-4 45℃ 3.23 x 10 ^-6 6.16 x 10 ^-6 2.66 x 10 ^-6 2.65 x 10 ^-6 6.69 x 10 ^-5 2.65 x 10 ^-5 25℃ 2.53 x 10 ^-8 2.36 x 10 ^-8 1.82 x 10 ^-8 2.09 x 10 ^-8 1.52 x 10 ^-6 1.24 x 10 ^-7

According to FIG. 6 and Table 2, as the calcination temperature increases overall, the ion conductivity increases at a relatively low operating temperature, and the solid electrolyte sheets according to Examples 2-1 to 2-4 show an almost similar pattern, but The solid electrolyte sheets according to Examples 2-5 and 2-6 exhibit more differentiated ion conduction properties, and when measured at 25° C. and 45° C. for Example 2-5, Examples 2-1 to 2-4 1-2 order increase, and the ionic conductivity at 45 ° C was greatly increased to 6.69 x 10 ^-5 S/cm. However, when measured at 70 ° C., the ionic conductivity increases in proportion to the calcination temperature, and in the case of Example 2-5, 7.39 x 10 ^-4 S / cm, in the case of Example 2-6, 8.6 x 10 ^-4 S / cm indicate This ionic conductivity is about twice or more than that of the solid electrolyte sheet according to Examples 2-1 to 2-3, and the ionic conductivity of the conventional solid electrolyte sheet applied with Li _6.25 Ga _0.25 La ₃ Zr ₂ O ₁₂ (4.41 x 10 ^-4 S/cm) showed about 2 times better ion conductivity. In addition, it can be seen that the ionic conductivity increases most at 45 ° C. Among them, the solid electrolyte sheet according to Examples 2-5 showed the highest value (6.69 x 10 ^-5 S / cm). This is determined to be highly correlated with the crystallite size of the solid electrolyte according to Examples 1-5 of the XRD analysis described in Test Example 1.

Test Example 4: Analysis of LSV characteristics of solid electrolyte sheet

7 is a graph of LSV characteristics of the solid electrolyte sheets according to Examples 2-3 and 2-5. LSV to evaluate the anodic potential stability of the solid electrolyte sheets according to Examples 2-3 and 2-5 including Examples 1-3 and 1-5 in which the crystal size of the Ga, Rb-LLZO solid electrolyte is most contrasted properties were evaluated.

Referring to FIG. 7 , it can be seen that the oxidation potential of Example 2-5 is almost the same as that of Example 2-3, but the value of oxidation current is further increased. This may be because, in the case of Examples 1-5 (calcination at 1100 ° C), the size of the particles increases and the specific surface area decreases, so the content of the bulky PEO polymer relatively decreases. Therefore, in the case of future Examples 1-5 (calcination at 1100 ° C), the effect of reducing the content of the polymer (binder) can be obtained, and through this, the content of LLZO is increased, thereby increasing the ionic conductivity and the effect can be expected.

Test Example 5: Evaluation of charge and discharge characteristics of all-solid-state battery

8 is an initial charge/discharge curve of an all-solid-state lithium secondary battery according to Device Examples 1 to 3, and FIG. 9 is a charge/discharge cycle and coulombic efficiency of an all-solid-state lithium secondary battery according to Device Examples 1 to 3. FIG. is the evaluation result of the rate characteristics of the all-solid-state lithium secondary battery according to Device Examples 1 to 3. The evaluation of charge/discharge characteristics was performed at 70℃, 0.1C 3cyc, and then about 50 cycles were performed in the range of 3.0~4.1V with 0.33C charge/discharge current. In addition, high-rate characteristics such as 0.1C, 0.2C, 0.33C, 0.5C, and 1C were evaluated for each of Device Examples 1 to 3.

According to FIG. 8 , in the case of Device Examples 1 and 2, the discharge capacity is very similar to about 130 mAh/g, but in the case of Device Example 3, it can be seen that the discharge capacity increases to about 138 mAh/g.

In addition, according to FIG. 9 , Device Examples 1 to 3 initially showed a charge/discharge efficiency of about 90%, but showed an efficiency of about 98% or more after about 5 cycles. In particular, in the case of Device Example 3, not only the initial capacity but also the discharge capacity according to the cycle and the coulombic efficiency were 100%, showing excellent characteristics.

Also, according to FIG. 10 , it can be seen that as the current density increases, Device Example 3 exhibits superior high-rate characteristics compared to Device Examples 1 and 2. In particular, Device Example 3 shows an improvement of 35% or more compared to Device Example 2 even at a high rate of 1C rate. In addition, Device Example 3 can confirm a high capacity retention rate of 85% at 1C compared to 0.1C.

Therefore, it can be seen that the characteristics of the Ga-Rb co-doped LLZO solid electrolyte powder required according to the positive electrode and the composite solid electrolyte sheet are different. In other words, Ga-Rb co-doped LLZO powder (calcined at 900℃), a nano-grade ion conductor, is applied to the cathode to increase the utilization rate of NCM-424 active material and improve the interface properties between inorganic particles such as active material, Super-P and LLZO powder. It is advantageous to do this, and it was confirmed that the application of Ga-Rb co-doped LLZO powder (calcined at 1100 ° C) having a relatively high crystal size to the composite solid electrolyte sheet has an advantageous effect on improving cell performance.

The scope of the present invention is indicated by the following claims rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be construed as being included in the scope of the present invention. do.

Claims (17)

It includes a powder having lithium lanthanum zirconium oxide (LLZO) doped with gallium (Ga) and rubidium (Rb) represented by Formula 1 below,
The powder has a lattice constant of 12.96620 to 12.97440 Å and a crystal size of 860 to 3,990 Å, a solid electrolyte for an all-solid-state lithium secondary battery.
[Formula 1]
Li _x Ga _p La _y Rb _q Zr _z O ₁₂ (5≤x≤9, 0<p≤1, 0<q≤1, 2≤y≤4, 1≤z≤3) According to claim 1,
The powder has a lattice constant of 12.97320 to 12.97440 Å and a crystal size of 860 to 1,550 Å. According to claim 1,
The powder has a lattice constant of 12.96780 to 12.96910 Å and a crystal size of 2,220 to 3,990 Å. According to claim 1,
The powder is a solid electrolyte for an all-solid lithium secondary battery, characterized in that the particle size is 3 to 10㎛. According to claim 2,
The ion conductivity of the composite solid electrolyte sheet including the solid electrolyte according to claim 2 and the binder is
1.80 x 10 ^-8 to 2.40 x 10 ^-8 S/cm at 25 °C;
2.65 x 10 ^-6 to 6.20 x 10 ^-6 S/cm at 45 °C;
A solid electrolyte for an all-solid-state lithium secondary battery, characterized in that 2.80 x 10 ^-4 to 4.55 x 10 ^-4 S / cm at 70 ℃. According to claim 3,
The ion conductivity of the composite solid electrolyte sheet including the solid electrolyte according to claim 3 and the binder is
2.05 x 10 ^-8 to 1.55 x 10 ^-6 S/cm at 25 °C;
2.60 x 10 ^-6 to 6.70 x 10 ^-5 S/cm at 45 °C;
A solid electrolyte for an all-solid-state lithium secondary battery, characterized in that 5.10 x 10 ^-4 to 7.45 x 10 ^-4 S / cm at 70 ° C. a positive electrode including a first solid electrolyte;
a composite solid electrolyte sheet formed on the anode and including a second solid electrolyte; and
Including; a negative electrode formed on the composite solid electrolyte sheet,
The first and second solid electrolytes each include a powder having lithium lanthanum zirconium oxide (LLZO) doped with gallium (Ga) and rubidium (Rb) represented by Formula 1 below, and the powder has a lattice constant is 12.96620 to 12.97440 Å, and the crystal size is 860 to 3,990 Å, the all-solid-state lithium secondary battery.
[Formula 1]
Li _x Ga _p La _y Rb _q Zr _z O ₁₂ (5≤x≤9, 0<p≤1, 0<q≤1, 2≤y≤4, 1≤z≤3) (a) A mixed solution in which an aqueous solution of a metal precursor including a lanthanum (La) precursor, a zirconium (Zr) precursor, a gallium (Ga) precursor, and a rubidium (Rb) precursor, a complexing agent, and a pH adjusting agent is mixed in a Taylor vortex state Co-precipitation to prepare a solid electrolyte precursor slurry;
(b) preparing a solid electrolyte precursor by washing and drying the solid electrolyte precursor slurry;
(c) preparing a mixture by mixing the solid electrolyte precursor with a lithium source; and
(d) preparing a powder having lithium lanthanum zirconium oxide (LLZO) doped with gallium (Ga) and rubidium (Rb) represented by Formula 1 below by calcining the mixture at a temperature of 700 to 1,200 ° C; including,
The powder has a lattice constant of 12.96620 to 12.97440 Å, and a crystal size of 860 to 3,990 Å, a method for producing a solid electrolyte.
[Formula 1]
Li _x Ga _p La _y Rb _q Zr _z O ₁₂ (5≤x≤9, 0<p≤1, 0<q≤1, 2≤y≤4, 1≤z≤3) According to claim 8,
In step (d),
When the mixture is calcined at a temperature of 800 to 900 ° C., a method for producing a solid electrolyte, characterized in that the crystal size of the powder decreases as the temperature increases. According to claim 9,
In step (d),
When the mixture is calcined at a temperature of 800 to 900 ° C,
A method for producing a solid electrolyte, characterized in that the crystal size of the powder is 860 to 1,550 Å. According to claim 8,
In step (d),
When the mixture is calcined at a temperature of 1,000 to 1,100 ° C., a method for producing a solid electrolyte, characterized in that the crystal size of the powder increases as the temperature increases. According to claim 11,
In step (d),
When the mixture is calcined at a temperature of 1,000 to 1,100 ° C,
A method for producing a solid electrolyte, characterized in that the crystal size of the powder is 2,220 to 3,990 Å. According to claim 11,
In step (d),
When the mixture is calcined at a temperature of 1,000 to 1,100 ° C,
Method for producing a solid electrolyte, characterized in that the grain boundary resistance of the powder decreases as the temperature increases. According to claim 5,
In step (d),
When the mixture is calcined at a temperature of 700 to 900 ° C., the powder forms secondary particles by bonding between primary particles or local sintering. According to claim 8,
In step (d),
When the mixture is calcined at a temperature of 1,000 to 1,200 ° C., the powder forms high-density single particles with a lattice size grown by sintering between primary particles. According to claim 8,
The lanthanum precursor is lanthanum nitrate (La(NO ₃ ) ₃ ) or a hydrate thereof,
The zirconium precursor is zirconium hydrochloride (ZrOCl ₂ ) or a hydrate thereof,
The gallium precursor is gallium nitrate (Ga(NO ₃ ) ₃ ) or a hydrate thereof,
A method for producing a solid electrolyte, characterized in that the rubidium precursor is rubidium nitrate (RbNO ₃ ) or a hydrate thereof. (1) preparing a positive electrode comprising the solid electrolyte prepared according to claim 8;
(2) preparing a composite solid electrolyte sheet comprising the solid electrolyte prepared according to claim 8;
(3) manufacturing a laminate by laminating the positive electrode and the composite solid electrolyte sheet; and
(4) disposing a negative electrode on the composite solid electrolyte sheet of the laminate;
A method for manufacturing an all-solid-state lithium secondary battery comprising:

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