Additive for all-solid-state rechargeable batteries, solid electrolyte membrane, and all-solid-state rechargeable battery

Abstract

The present invention relates to an additive for all-solid-state rechargeable batteries, a solid electrolyte membrane, and an all-solid-state rechargeable battery, the additive comprising: porous silica nanoparticles; and a solid electrolyte reactive compound located inside the pores of the porous silica nanoparticles, wherein the solid electrolyte reactive compound has a melting point of 100ºC to 170ºC and includes a heteroatom-containing functional group.

Description

Additives for all-solid-state secondary batteries, solid electrolyte membranes, and all-solid-state secondary batteries

[0001] It relates to an additive for an all-solid-state secondary battery, a solid electrolyte membrane, and an all-solid-state secondary battery.

[0002] Lithium secondary batteries, which offer high energy density and portability, are primarily used as power sources for mobile information terminals such as mobile phones, laptops, and smartphones. Recently, active research is underway to utilize high-energy-density lithium secondary batteries as power sources for hybrid and electric vehicles, or as power storage devices.

[0003] Because lithium secondary batteries on the market use electrolytes containing flammable organic solvents, there is a safety issue that the batteries may explode or catch fire in the event of a collision or penetration.

[0004] Accordingly, all-solid-state secondary batteries, which utilize solid electrolytes instead of liquid electrolytes, are being proposed. All-solid-state secondary batteries are composed entirely of solid materials, offering safety advantages such as no risk of electrolyte leakage or explosion, and the ease of manufacturing thin batteries. Furthermore, a reduced anode thickness allows for improved high-speed charge / discharge performance, enabling high-voltage operation and high-energy density.

[0005] Provided are an additive capable of blocking ionic current at high temperatures and inducing shutdown of the battery in the event of an abnormal reaction in an all-solid-state secondary battery, a solid electrolyte membrane, and an all-solid-state secondary battery with improved safety and reliability including the same.

[0006] In one embodiment, an additive for an all-solid-state secondary battery is provided, comprising: porous silica nanoparticles; and a solid electrolyte reactive compound positioned within the pores of the porous silica nanoparticles; wherein the solid electrolyte reactive compound has a melting point of 100°C to 170°C and includes a heteroatom-containing functional group.

[0007] In another embodiment, a method for producing an additive for an all-solid-state secondary battery is provided, comprising obtaining a mixture of a solid electrolyte reactive compound and porous silica nanoparticles, heating the mixture to a temperature higher than the melting point of the solid electrolyte reactive compound, cooling to solidify, separating the solidified product, and drying the solidified product, wherein the solid electrolyte reactive compound has a melting point of 100°C to 170°C and includes a heteroatom-containing functional group.

[0008] In another embodiment, a solid electrolyte membrane is provided, comprising a solid electrolyte; and an additive for an all-solid-state secondary battery as described above.

[0009] In another embodiment, an all-solid-state secondary battery is provided, comprising: a positive electrode; a negative electrode; and the aforementioned solid electrolyte membrane positioned between the positive electrode and the negative electrode.

[0010] An additive for an all-solid-state secondary battery according to one embodiment can, when added to a solid electrolyte membrane, induce a shutdown of the battery by blocking ionic current when the temperature rises due to an abnormal reaction of the battery, thereby improving the safety and reliability of the all-solid-state secondary battery.

[0011] Figures 1 and 2 are cross-sectional views schematically showing an all-solid-state secondary battery according to one embodiment.

[0012] Figure 3 is a schematic diagram of an additive for an all-solid-state secondary battery according to one embodiment.

[0013] Figure 4 shows a photograph of the porous silica nanoparticles manufactured in Comparative Example 1 taken using a transmission electron microscope (TEM).

[0014] Figure 5 shows a transmission electron microscope (TEM) photograph of an additive for an all-solid-state secondary battery manufactured in Example 1.

[0015] Figure 6 shows a photograph of the porous silica nanoparticles manufactured in Comparative Example 1 taken using a transmission electron microscope (TEM).

[0016] Figure 7 shows a transmission electron microscope (TEM) photograph of an additive for an all-solid-state secondary battery manufactured in Example 1.

[0017] Figure 8 shows the results of FT-NMR analysis over time at high temperature conditions for the additive for an all-solid-state secondary battery manufactured in Example 1.

[0018] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention. The present invention is defined solely by the scope of the claims set forth below.

[0019] Unless otherwise specified herein, when a part such as a layer, film, region, or plate is said to be “on top of” another part, this includes not only cases where it is “directly on top of” the other part, but also cases where there is another part in between.

[0020] Unless otherwise specified herein, the singular may also include the plural. Furthermore, unless otherwise specified, "A or B" may mean "including A, including B, or including A and B."

[0021] As used herein, “combination thereof” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the components.

[0022] Unless otherwise defined herein, the particle size may be the average particle size. In addition, the particle size refers to the average particle size (D50), which means the diameter of particles with a cumulative volume of 50% by volume in a particle size distribution. The average particle size (D50) can be measured by a method well known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope (TEM) photograph or a scanning electron microscope (SEM) photograph. Alternatively, the average particle size (D50) value can be obtained by measuring with a measuring device that utilizes dynamic light-scattering, performing data analysis to count the number of particles for each particle size range, and calculating from the counted number. Alternatively, the average particle size (D50) value can be obtained by measuring with a laser diffraction method. When measuring by laser diffraction, more specifically, after the particles to be measured are dispersed in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasonic waves of approximately 28 kHz at an output of 60 W, and the average particle size (D50) based on 50% of the particle size distribution in the measuring device can be calculated.

[0023] It should be understood that the terms "include," "comprising," or "having" herein are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0024] Also, the term "layer" here includes not only a shape formed on the entire surface when observed in a plan view, but also a shape formed on a portion of the surface.

[0025] "Metal" is interpreted as a concept that includes ordinary metals, transition metals, and metalloids (semi-metals).

[0026] "Substitution" means that at least one hydrogen atom is substituted with a halogen atom (F, Cl, Br, I), a hydroxyl group, a C1 to C20 alkoxy group, a nitro group, a cyano group, an amine group, an imino group, an azido group, an amidino group, a hydrazino group, a hydrazono group, a carbonyl group, a carbamyl group, a thiol group or a salt thereof, a thioether group, an ester group, an ether group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid or a salt thereof, a C1 to C20 alkyl group, a C2 to C20 alkenyl group, a C2 to C20 alkynyl group, a C6 to C20 aryl group, a C3 to C20 cycloalkyl group, a C3 to C20 cycloalkenyl group, a C3 to C20 cycloalkynyl group, a C2 to C20 heterocycloalkyl group, a C2 to C20 It means substituted with a C20 heterocycloalkenyl group, a C2 to C20 heterocycloalkynyl group, a C3 to C20 heteroaryl group, or a combination thereof.

[0027] Additives for all-solid-state secondary batteries

[0028] In one embodiment, an additive for an all-solid-state secondary battery is provided, comprising: porous silica nanoparticles; and a solid electrolyte reactive compound positioned within the pores of the porous silica nanoparticles; wherein the solid electrolyte reactive compound has a melting point of 100°C to 170°C and includes a heteroatom-containing functional group.

[0029] When using additives in all-solid-state secondary batteries, careful selection of additives is necessary, as side reactions between the additives and the solid electrolyte can affect battery performance. In particular, sulfide-based solid electrolytes, which have excellent ionic conductivity and are used as solid electrolytes in all-solid-state secondary batteries, are susceptible to deterioration by air, moisture, polar solvents, or high temperatures, necessitating careful selection of additives.

[0030] In one embodiment, the additive can be added to a solid electrolyte membrane and used, and can induce a shutdown by blocking the ionic current when the temperature rises due to Joule heating in a situation such as penetration or short circuit of the battery. For example, the additive can induce a shutdown by lowering the ionic conductivity when the solid electrolyte reactive compound begins to melt in the temperature range of 100°C to 170°C, and the solid electrolyte reactive compound escapes from the pores of the porous silica nanoparticles and reacts with the solid electrolyte. Through this, the additive can act at a temperature lower than 180°C, which is the melting point of lithium metal, when the temperature rises due to Joule heating in a situation such as penetration or short circuit of the battery, and can effectively suppress the desorption or penetration phenomenon of liquid lithium formed when the negative electrode metal is melted at a high temperature. Accordingly, the additive may also be expressed as a safety additive or a shutdown additive.

[0031] The above additive has little reactivity with solid electrolytes, such as sulfide-based solid electrolytes, within the electrolyte membrane during normal operation or battery operation, and thus may not deteriorate the solid electrolyte. Furthermore, the above additive can perform a shutdown function even in small amounts, thereby improving high-temperature safety without lowering the ionic conductivity of the solid electrolyte membrane within the battery during normal operation or degrading performance.

[0032] When the above additive is added to a solid electrolyte membrane, it can be dispersed and present within the membrane. The above additive has no effect within the solid electrolyte membrane under normal conditions or during battery operation. However, when the battery is subjected to high temperatures of 100°C or higher due to an abnormal reaction, the solid electrolyte reactive compound located within the pores of the porous silica nanoparticles can melt and escape from the pores, thereby performing a shutdown function.

[0033] To perform this shutdown function, an additive for an all-solid-state secondary battery comprises porous silica nanoparticles; and a solid electrolyte reactive compound positioned within the pores of the porous silica nanoparticles. To explain the structure of this additive, a schematic diagram of an additive according to one embodiment is shown in FIG. 3.

[0034] To perform a high-temperature selective shutdown function, the additive comprises porous silica nanoparticles (1) capable of adsorbing a solid electrolyte reactive compound (2) so that it is positioned within the pores (11). The additive can be manufactured by methods such as immersion and heating so that the solid electrolyte reactive compound (2) can be positioned within the pores (11) of the porous silica particles (1).

[0035] By using porous silica nanoparticles with excellent thermal stability or reactive stability, the porous silica nanoparticles themselves can exist without deformation even under high-temperature conditions due to abnormal reactions of the battery, so that the shutdown function by the solid electrolyte reactive compound existing within the pores can be effectively performed. In addition, since there is no reactivity with the solid electrolyte during normal or battery operation, the solid electrolyte reactive compound can exist stably without causing a decrease in battery performance. When a solid electrolyte reactive compound with a shutdown function is used in a battery, the ionic conductivity usually tends to decrease. However, in the case of the additive according to one embodiment, by using porous silica nanoparticles that prevent such solid electrolyte reactive compound from being located only within the pores and acting, so that it stably exists during normal or battery operation, the shutdown performance, which is a characteristic that conflicts with securing ionic conductivity, can be harmoniously secured.

[0036] In one embodiment, the average particle diameter of the porous silica nanoparticles may be 100 nm or more, for example, 120 nm or more, 180 nm or more, 130 nm or more, 150 nm or more, 180 nm or more, or 200 nm or more. In addition, the average particle diameter of the porous silica nanoparticles may be 400 nm or less, for example, 380 nm or less, 350 nm or less, 320 nm or less, 300 nm or less, 280 nm or less, or 250 nm or less. Within this range, the additive can be uniformly dispersed and present, and high-temperature safety can be effectively secured without causing a deterioration in the performance of the battery. The average particle diameter of the above porous silica nanoparticles may be measured from an electron microscope image, for example, by measuring the sizes of about 20 particles in a scanning electron microscope (SEM) or transmission electron microscope (TEM) image to obtain a particle size distribution and calculating D50 from it.

[0037] For example, the average diameter of the pores of the porous silica nanoparticles may be 1 nm or more, for example, 2 nm or more, 3 nm or more, or 4 nm or more. In addition, the average diameter of the pores of the porous silica nanoparticles may be 20 nm or less, for example, 15 nm or less, 10 nm or less, 8 nm or less, or 6 nm or less. In this range, the solid electrolyte reactive compound is effectively positioned within the pores of the porous silica nanoparticles and effectively performs a high-temperature selective shutdown function, which may be advantageous in ensuring high-temperature safety. The average diameter of the pores may be measured by an electron microscope image, and for example, the diameter distribution may be obtained by measuring the sizes of about 20 pores in a scanning electron microscope (SEM) or transmission electron microscope (TEM) image, and D50 may be calculated from there. Alternatively, the average diameter of the above pores may be measured using a BET (Brunauer-Emmett-Teller) device using a gas adsorption method, or may be measured using a mercury intrusion method, etc.

[0038] In one embodiment, the volume of pores per unit mass of the porous silica nanoparticles is 0.01 cm 3 / g or more, for example 0.03 cm 3 / g or more, 0.05 cm 3 / g or more, or 0.1 cm 3 / g or more. In addition, the volume of pores per unit mass of the porous silica nanoparticles is 1 cm 3 / g or less, for example 0.8 cm 3 / g or less, 0.5 cm 3 / g or less, 0.3 cm 3 / g or less, or 0.2 cm 3 / g or less. In this range, the shutdown function of the additive can be effectively secured. At this time, the pore volume per unit mass of the porous silica nanoparticles can be measured using a BET (Brunauer-Emmett-Teller) device using a gas adsorption method, or can be measured using a mercury intrusion method, etc.

[0039] In one embodiment, the porous silica nanoparticles may be included in an amount of 10 wt% or more, for example, 15 wt% or more, 20 wt% or more, 25 wt% or more, 30 wt% or more, or 40 wt% or more, based on 100 wt% of the additive. In addition, the porous silica nanoparticles may be included in an amount of 90 wt% or less, for example, 85 wt% or less, 80 wt% or less, 75 wt% or less, 70 wt% or less, or 60 wt% or less, based on 100 wt% of the additive. Within this range, uniform dispersibility of the additive can be secured, and performance degradation of the battery can be effectively prevented and high-temperature safety can be effectively secured.

[0040] To perform a high-temperature selective shutdown function, the solid electrolyte reactive compound may have a melting point of 100°C or higher, for example, 110°C or higher, 120°C or higher, 130°C or higher, or 133°C or higher. In addition, the solid electrolyte reactive compound may have a melting point of 170°C or lower, for example, 169°C or lower, 168°C or lower, or 167°C or lower. In this range, the additive effectively acts at a temperature lower than 180°C, which is the melting point of lithium metal, which is an anode material, when heat is generated due to an abnormal reaction of the battery, thereby suppressing the desorption or penetration of liquid lithium melted at high temperatures by the anode metal.

[0041] The above solid electrolyte reactive compound includes a heteroatom-containing functional group. The heteroatom-containing functional group is a functional group that can react with a solid electrolyte (particularly, a sulfide-based solid electrolyte). Since the solid electrolyte reactive compound includes the heteroatom-containing functional group, the solid electrolyte reactive compound that is melted and escapes from the pores of the porous silica nanoparticles under high-temperature conditions due to an abnormal reaction of the battery can react with the solid electrolyte to lower ionic conductivity and perform a shutdown function for the battery.

[0042] For example, the heteroatom may include sulfur (S), oxygen (0), nitrogen (N), or a combination thereof. When the additive includes the aforementioned heteroatom, the solid electrolyte reactive compound melted under high-temperature conditions due to an abnormal reaction of the battery can effectively react with the solid electrolyte to reduce ionic conductivity. Alternatively, the heteroatom may include oxygen, nitrogen, or a combination thereof, in which case the solid electrolyte reactive compound melted under high-temperature conditions can effectively react with the sulfide-based solid electrolyte to perform a shutdown function.

[0043] In one embodiment, the solid electrolyte reactive compound may include one or more heteroatom-containing functional groups, or may include two or more heteroatom-containing functional groups. In terms of ensuring reactivity with a solid electrolyte, the greater the number of heteroatom-containing functional groups, the better the reactivity, and therefore, the upper limit thereof may not be specifically limited.

[0044] For example, the solid electrolyte reactive compound may contain two or more of the heteroatom-containing functional groups, for example, three or more, four or more, or five or more. In addition, the solid electrolyte reactive compound may contain no more than 15 of the heteroatom-containing functional groups, for example, twelve or less, ten or less, eight or less, or six or less. In this case, the additive may effectively react with the solid electrolyte under high-temperature conditions due to an abnormal reaction of the battery.

[0045] For example, the hetero atom-containing functional group may include a hydroxyl group (-OH), a salt of a hydroxyl group, a thiol group (-SH), a salt of a thiol group, an amino group (-NH2), an amine group (-NRH or -NRR', wherein R and R' are each independently a substituted or unsubstituted C1 to C20 alkyl group; or a substituted or unsubstituted C6 to C20 aryl group; or a combination thereof), an aldehyde group (-CHO), a carboxyl group (-COOH), a salt of a carboxyl group, or a combination thereof. At this time, the hetero atom-containing functional group may be one in which at least one hydrogen is substituted with an additional substituent. The description of the substituent in the above-mentioned “substitution” may be equally applied to the additional substituent, and for example, the additional substituent may be unsubstituted or substituted with a C1 to C20 alkyl group, a C6 to C20 aryl group, or a combination thereof. For example, when the heteroatom-containing functional group is a hydroxyl group, the heteroatom-containing functional group may be substituted with a C1 to C20 alkyl group instead of the hydrogen of the hydroxyl group. When the above-described exemplary functional group is used, the molten solid electrolyte reactive compound can effectively react with the solid electrolyte under high-temperature conditions due to the abnormal reaction of the battery, thereby reducing ionic conductivity and advantageously securing a shutdown function.

[0046] For example, the heteroatom-containing functional group may include a substituted or unsubstituted hydroxyl group, a salt of a substituted or unsubstituted hydroxyl group, a substituted or unsubstituted thiol group, a salt of a substituted or unsubstituted thiol group, a substituted or unsubstituted amino group, a substituted or unsubstituted amine group, a substituted or unsubstituted aldehyde group, a substituted or unsubstituted carboxyl group, a salt of a substituted or unsubstituted carboxyl group, or a combination thereof. Here, the above description is equally applicable to the “substitution”. For example, the “substitution” may mean that at least one hydrogen in the above-described functional group is replaced with a substituent of a C1 to C20 alkyl group, a C6 to C20 aryl group, or a combination thereof. In addition, the salt may include all those conventional in the art, and a representative example thereof may be a metal salt, and may include a metal such as Na, K, Li, or a combination thereof. When the functional group exemplified above is included, the molten solid electrolyte reactive compound can effectively react with the solid electrolyte under high-temperature conditions due to an abnormal reaction of the battery, thereby reducing ionic conductivity and advantageously securing a shutdown function. In one embodiment, the heteroatom-containing functional group may include at least one oxygen-containing functional group. Alternatively, the solid electrolyte reactive compound may include at least two heteroatom-containing functional groups, and the heteroatom-containing functional group may include at least one oxygen-containing functional group. In this case, the additive can effectively react with the solid electrolyte under high-temperature conditions due to an abnormal reaction of the battery.

[0047] For example, the solid electrolyte reactive compound may have a melting point of 100°C to 170°C and may include an amide, a saccharide, an aliphatic organic acid, an aromatic organic acid, or a combination thereof. Alternatively, the solid electrolyte reactive compound may have a melting point of 100°C to 170°C and may include a C1 to C10 amide, a C5 to C20 saccharide, a C1 to C20 aliphatic organic acid, a C6 to C20 aromatic organic acid, or a combination thereof. When this is satisfied, the shutdown function of the battery by the additive can be effectively secured.

[0048] The solid electrolyte reactive compound may include, for example, urea, thiourea, glucose, galactose, citric acid, salicylic acid, or a combination thereof. Here, the solid electrolyte reactive compound is one of the compounds described above, which may be unsubstituted or substituted with an additional substituent, and the description of “substitution” described above may be applied equally to the additional substituent, and may be unsubstituted or substituted with, for example, a C1 to C20 alkyl group or a C6 to C20 aryl group. The solid electrolyte reactive compound may be one or more selected from urea, thiourea, glucose, citric acid, salicylic acid, galactose, or a combination thereof, and may be a compound having a melting point of 100°C to 170°C. For example, when the solid electrolyte reactive compound is glucose, it may be D-glucose or L-glucose. When the solid electrolyte reactive compound is citric acid, it may be 2-hydroxypropane-1,2,3-tricarboxylic acid or isocitric acid, which is a structural isomer of citric acid. When the solid electrolyte reactive compound is salicylic acid, it may be o-salicylic acid, or when the solid electrolyte reactive compound is galactose, it may be D-galactose and / or L-galactose. Alternatively, when the solid electrolyte reactive compound is thiourea, it may be N,N'-diphenyl thiourea having a melting point of 152°C to 155°C. When the above-described solid electrolyte reactive compound is used, the solid electrolyte reactive compound can effectively react with the solid electrolyte under high-temperature conditions due to an abnormal reaction of the battery, which can be more advantageous in securing the shutdown function and high-temperature safety of the battery.

[0049] In one embodiment, the solid electrolyte reactive compound may have a molecular weight of 30 g / mol or more, for example, 40 g / mol or more, 50 g / mol or more, 55 g / mol or more, or 60 g / mol or more. In addition, the solid electrolyte reactive compound may have a molecular weight of 900 g / mol or less, for example, 800 g / mol or less, 600 g / mol or less, 500 g / mol or less, 400 g / mol or less, 350 g / mol or less, 300 g / mol or less, or 250 g / mol or less. In this range, the additive effectively acts at a temperature lower than 180°C, which is the melting point of lithium metal, which is an anode material, when heat is generated due to an abnormal reaction of the battery, thereby suppressing the desorption or penetration of liquid lithium melted at high temperatures by the anode metal.

[0050] The solid electrolyte reactive compound may be included in an amount of 10 wt% or more, for example, 15 wt% or more, 20 wt% or more, 25 wt% or more, 30 wt% or more, or 40 wt% or more, based on 100 wt% of the additive. In addition, the solid electrolyte reactive compound may be included in an amount of 90 wt% or less, for example, 85 wt% or less, 80 wt% or less, 75 wt% or less, 70 wt% or less, or 60 wt% or less, based on 100 wt% of the additive. Within this range, the solid electrolyte reactive compound can effectively react with the solid electrolyte under high-temperature conditions due to an abnormal reaction of the battery, and thus, it may be more advantageous in securing the shutdown function and high-temperature safety of the battery.

[0051] Method for manufacturing additives for all-solid-state secondary batteries

[0052] In one embodiment, a method for producing an additive for an all-solid-state secondary battery is provided, comprising obtaining a mixture of a solid electrolyte reactive compound and porous silica nanoparticles, heating the mixture to a temperature higher than the melting point of the solid electrolyte reactive compound, cooling to solidify, separating the solidified product, and drying the solidified product, wherein the solid electrolyte reactive compound has a melting point of 100°C to 170°C and includes a heteroatom-containing functional group.

[0053] The above description relates to a method for manufacturing an additive for an all-solid-state secondary battery, which is an example of an embodiment. Hereinafter, descriptions overlapping with the above description of the additive for an all-solid-state secondary battery will be omitted, and processes for manufacturing an additive for an all-solid-state secondary battery, which is an example of an embodiment, will be described in detail.

[0054] First, a mixture is obtained by mixing a solid electrolyte reactive compound with porous silica nanoparticles. Here, the solid electrolyte reactive compound has a melting point of 100°C to 170°C and includes a heteroatom-containing functional group. For example, in the mixture, the mixing ratio of the porous silica nanoparticles and the solid electrolyte reactive compound may be 10:90 to 90:10 by weight. Within this range, an additive that performs a high-temperature selective shutdown function can be effectively produced.

[0055] Next, the mixture is heated to a temperature higher than the melting point of the solid electrolyte reactive compound, and then cooled to solidify. For example, the temperature of the heating is sufficient if it is higher than the melting point of the solid electrolyte reactive compound, and the upper limit of the temperature may not be particularly limited, and for example, it may be +50 ℃ or lower than the melting point of the solid electrolyte reactive compound. The heating may be performed for 1 hour to 10 hours, for example, 2 hours to 8 hours, 3 hours to 7 hours, or 5 hours to 6 hours, and for example, may be performed under a vacuum atmosphere. In this case, the heating time includes the time for heating to a temperature higher than the melting point and maintaining it, and stirring may be performed during the heating. When this is satisfied, an additive in which the solid electrolyte reactive compound is located inside the pores of porous silica nanoparticles can be effectively manufactured.

[0056] For example, after the heating, cooling can be performed to room temperature of 25°C to 27°C, and within this range, the solid electrolyte reactive compound can be effectively positioned within the pores of the porous silica nanoparticles.

[0057] Thereafter, the solidified product is separated and dried. The separation may be a solid-liquid separation, and for example, the solidified product may be separated by centrifugation. The drying may be performed at a temperature of 50°C to 100°C, for example, 55°C to 90°C, or 60°C to 80°C. In addition, the drying may be performed for 1 hour to 50 hours, for example, 5 hours to 40 hours, 10 hours to 30 hours, or 20 hours to 28 hours, and may be performed under a vacuum atmosphere. When this is satisfied, an additive in which the solid electrolyte reactive compound is located within the pores of porous silica nanoparticles can be effectively manufactured.

[0058] solid electrolyte membrane

[0059] In one embodiment, a solid electrolyte membrane is provided, comprising a solid electrolyte; and an additive for an all-solid-state secondary battery as described above.

[0060] Since the above solid electrolyte membrane includes an additive for an all-solid-state secondary battery according to one embodiment, when the temperature rises due to an abnormal reaction of the battery, it is possible to induce a shutdown of the battery by blocking ion current at a high temperature, thereby securing an all-solid-state secondary battery with excellent safety and reliability.

[0061] For example, the additive for the all-solid-state secondary battery may be included in an amount of 1 wt% to 15 wt%, for example, 1 wt% to 13 wt%, or 2 wt% to 10 wt%, based on 100 wt% of the solid electrolyte. Within this range, the additive may effectively block ionic current under high-temperature conditions, thereby inducing shutdown of the battery, without impairing the performance of the solid electrolyte membrane.

[0062] solid electrolyte

[0063] The above solid electrolyte membrane includes a solid electrolyte, and the solid electrolyte may include a solid electrolyte selected from, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof. The types of the above-mentioned solid electrolytes are described in detail below.

[0064] Sulfide-based solid electrolyte

[0065] The above solid electrolyte membrane may particularly include a sulfide-based solid electrolyte, and the sulfide-based solid electrolyte is, for example, Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element, for example, I or Cl), 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 (m, n are integers, Z is Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are integers, and M is P, Si, Ge, B, Al, Ga or In), or a combination thereof.

[0066] Such sulfide-based solid electrolytes can be obtained, for example, by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or 50:50 to 80:20, and optionally heat-treating them. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be produced. Here, the ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3.

[0067] Methods for mixing sulfur-containing raw materials for producing sulfide-based solid electrolytes include mechanical milling or the solution method. Mechanical milling involves placing raw materials in a ball mill reactor and vigorously stirring them to finely atomize and mix them. Using the solution method, the raw materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. Furthermore, heat treatment after mixing can solidify the crystals of the solid electrolyte and improve ionic conductivity. For example, a sulfide-based solid electrolyte can be produced by mixing sulfur-containing raw materials and heat-treating them twice or more, resulting in a sulfide-based solid electrolyte with high ionic conductivity and robustness.

[0068] According to one embodiment, a sulfide-based solid electrolyte can be manufactured through, for example, a first heat treatment in which sulfur-containing raw materials are mixed and calcined at 120°C to 350°C, and a second heat treatment in which the first heat treatment result is mixed and calcined at 350°C to 800°C. The first heat treatment and the second heat treatment can each be performed in an inert gas or nitrogen atmosphere. The first heat treatment can be performed for 1 to 10 hours, and the second heat treatment can be performed for 5 to 20 hours. The first heat treatment can have the effect of milling small raw materials, and the second heat treatment can synthesize the final solid electrolyte. Through two or more such heat treatments, a high-performance sulfide-based solid electrolyte with high ionic conductivity and robustness can be obtained, and such a solid electrolyte can be said to be suitable for mass production. The temperature of the first heat treatment may be, for example, 150°C to 330°C, or 200°C to 300°C, and the temperature of the second heat treatment may be, for example, 380°C to 700°C, or 400°C to 600°C.

[0069] For example, the sulfide-based solid electrolyte may be in the form of particles and may include argyrodite-type sulfides. These argyrodite-type sulfide-based solid electrolyte particles have an ionic conductivity of 10, which is the ionic conductivity of a typical liquid electrolyte at room temperature. -4 10 inland -2 It possesses high ionic conductivity approaching the S / cm range. Furthermore, it can form a close bond between the positive electrode active material and the solid electrolyte without causing a decrease in ionic conductivity, and can form a close interface between the electrode and the solid electrolyte membrane. An all-solid-state secondary battery including this can exhibit improved battery performance, such as rate characteristics, Coulombic efficiency, and cycle life characteristics.

[0070] The above argyrodite-type sulfide-based solid electrolyte may include, for example, a compound represented by the chemical formula 1 below.

[0071] [Chemical Formula 1]

[0072] (Li a M 1 b M 2 c )(P d M 3 e )(S f M 4 g )X h

[0073] In the above chemical formula 1, 4≤a≤8, and M 1 is Mg, Cu, Ag, or a combination thereof, and 0≤b<0.5, and M 2 is Na, K, or a combination thereof, 0≤c<0.5, and M 3 is Sn, Zn, Si, Sb, Ge, or a combination thereof, and 0 <d<4, 0≤e<1 이고, M 4 is O, SO n , or a combination thereof, and 1.5≤n≤5, 3≤f≤12, 0≤g<2, and X is F, Cl, Br, I, or a combination thereof, and 0≤h≤2.

[0074] For example, in chemical formula 1, a halide element (X) may be included as an essential element, in which case 0 <h≤2로 표시될 수 있다. 일 예로 화학식 1에 M 1 Elements may be required, in which case 0 <b<0.5로 표시될 수 있다. 화학식 1에서 M 3 can be understood as an element substituted in the P position, and 0 <e<1일 수 있다. 화학식 1에서 M 4 is substituted in the S position, for example, 0 <g<2일 수 있으며, S의 비율인 f는 예를 들어 3≤f≤7일 수 있다. M 4 Go SO n If SO n It can be, for example, S4O6, S3O6, S2O3, S2O4, S2O5, S2O6, S2O7, S2O8, SO4, or SO5, and can be, for example, SO4.

[0075] For example, in chemical formula 1, a+b+c+h=7, d+e=1, and f+g+h=6.

[0076] As a specific example, argyrodite-type sulfide-based solid electrolyte particles include Li3PS4 and Li7P3S. 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 , Li 5.75 PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )PS 4.75 Cl 1.25 , (Li 5.72 Cu 0.03 )PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )P(S 4.70 (SO4) 0.05 )Cl 1.25 , (Li 5.69Cu 0.06 )P(S 4.60 (SO4) 0.15 )Cl 1.25 , (Li 5.72 Cu 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , (Li 5.72 Na 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , Li 5.75 P(S 4.725 (SO4) 0.025 )Cl 1.25 , or combinations thereof, but are not limited thereto.

[0077] An argyrodite-type sulfide-based solid electrolyte can be manufactured, for example, by mixing lithium sulfide and phosphorus sulfide, optionally a lithium halide. After mixing these, a heat treatment may be performed. The heat treatment may include, for example, two or more heat treatment steps. Here, manufacturing an argyrodite-type sulfide-based solid electrolyte may include, for example, a first heat treatment of mixing raw materials and calcining at 120°C to 350°C, and a second heat treatment of mixing the resultant of the first heat treatment again and calcining at 350°C to 800°C.

[0078] The average particle size (D50) of the sulfide-based solid electrolyte particles may be, for example, 0.1 ㎛ to 5.0 ㎛ or 0.1 ㎛ to 3.0 ㎛, and may be small particles of 0.1 ㎛ to 1.9 ㎛ or large particles of 2.0 ㎛ to 5.0 ㎛. The sulfide-based solid electrolyte particles may be a mixture of small particles having an average particle size of 0.1 ㎛ to 1.9 ㎛ and large particles having an average particle size of 2.0 ㎛ to 5.0 ㎛. The average particle size of the sulfide-based solid electrolyte particles may be measured from an electron microscope image, and for example, a particle size distribution may be obtained by measuring the size (diameter or major axis length) of about 20 particles in a scanning electron microscope image, and the D50 may be calculated from this.

[0079] Oxide-based solid electrolyte

[0080] The solid electrolyte membrane may include an oxide-based solid electrolyte. The oxide-based solid electrolyte may be, for example, Li 1+x Ti 2-x Al(PO4)3(LTAP)(0≤x≤4), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(0≤x<1, 0≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 <x<2, 0<y<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-xSi y P 3-y O 12 (0≤x≤1, 0≤y≤1), lithium lanthanum titanate (Li x La y TiO3, 0 <x<2, 0<y<3), Li2O, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 가넷(Garnet)계 세라믹스 Li 3+x La3M2O 12 (M= Te, Nb, or Zr; x is an integer from 1 to 10), or mixtures thereof.

[0081] Halide-based solid electrolyte

[0082] The solid electrolyte membrane may include, for example, a halide-based solid electrolyte. The halide-based solid electrolyte contains a halogen element as a main component, and may mean that the ratio of the halide element to all elements constituting the solid electrolyte is 50 mol% or more, 70 mol% or more, 90 mol% or more, or 100 mol%. For example, the halide-based solid electrolyte may not contain a sulfur element.

[0083] The halide-based solid electrolyte may contain lithium element, a metal element other than lithium, and a halogen element. The metal element other than lithium may be Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof. The halogen element may be F, Cl, Br, I, or a combination thereof, and may be Cl, Br, or a combination thereof. The halide-based solid electrolyte may contain, for example, Li aM1X6 (M is Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof, X is F, Cl, Br, I, or a combination thereof, and 2≤a≤3) can be represented. The halide-based solid electrolyte may be, for example, Li2ZrCl6, Li 2.7 Y 0.7 Zr 0.3 Cl6, Li 2.5 Y 0.5 Zr 0.5 Cl6, Li 2.5 In 0.5 Zr 0.5 Cl6, Li2In 0.5 Zr 0.5 Cl6, Li3YBr6, Li3YCl6, Li3YBr2Cl4, Li3YbCl6, Li 2.6 Hf 0.4 Yb 0.6 Cl6, or combinations thereof, but is not limited thereto.

[0084] bookbinder

[0085] A solid electrolyte membrane according to one embodiment may further include a binder. Binders include, for example, nitrile-butadiene rubber, hydrogenated nitrile-butadiene rubber, styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluoroelastomer, natural rubber, polydimethylsiloxane, polyethylene oxide, polyvinylpyrrolidone, polyvinylpyridine, chlorosulfonated polyethylene, polyvinyl alcohol, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, polyamideimide, polyimide, poly(meth)acrylate, polyacrylonitrile, polystyrene, polyurethane, and the like. copolymers, or combinations thereof.

[0086] The binder may be included in an amount of 0.1 wt% to 3 wt% based on 100 wt% of the solid electrolyte membrane, for example, 0.5 wt% to 2 wt%, or 0.5 wt% to 1.5 wt%. When the binder is included in the above range, the components within the solid electrolyte membrane can be well bound without lowering the ionic conductivity of the solid electrolyte, thereby improving the durability and reliability of the battery.

[0087] Other ingredients

[0088] The solid electrolyte membrane may optionally further include other components such as alkali metal salts, and / or ionic liquids, and / or conductive polymers.

[0089] The alkali metal salt may be, for example, a lithium salt. The content of the lithium salt in the solid electrolyte membrane may be 1 M or more, for example, 1 M to 4 M. In this case, the lithium salt may improve ion conductivity by enhancing the lithium ion mobility of the solid electrolyte membrane.

[0090] The lithium salt may be applied without limitation on type, and may include, for example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiSCN, LiN(CN)2, lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), lithium difluorobis(oxalato)phosphate (LiDFBP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, or a combination thereof.

[0091] For example, the lithium salt may be an imide-based lithium salt such as LiTFSI, LiFSI, LiBETI, or a combination thereof. The imide-based lithium salt can maintain or improve ionic conductivity by appropriately maintaining chemical reactivity with the ionic liquid.

[0092] Ionic liquids are salts or molten salts that are composed only of ions and are liquid at room temperature, with a melting point below room temperature.

[0093] The ionic liquid comprises a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium, and mixtures thereof, and b) BF4. - , PF6 - , AsF6 - , SbF6 - , AlCl4 - , HSO4 - , ClO4 - , CH3SO3 - , CF3CO2 - , Cl - , Br - , I -, BF4 - , SO4 - , CF3SO3 - , (FSO2)2N - , (C2F5SO2)2N - , (C2F5SO2)(CF3SO2)N - , and (CF3SO2)2N - It may be a compound containing one or more anions selected from among.

[0094] The ionic liquid may include, for example, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, or a combination thereof.

[0095] In the above solid electrolyte membrane, the weight ratio of the solid electrolyte and the ionic liquid may be 0.1:99.9 to 90:10, for example, 10:90 to 90:10, 20:80 to 90:10, 30:70 to 90:10, 40:60 to 90:10, or 50:50 to 90:10. A solid electrolyte membrane satisfying the above range can maintain or improve ionic conductivity by improving the electrochemical contact area with the electrode. Accordingly, the energy density, discharge capacity, rate characteristics, etc. of the all-solid-state secondary battery can be improved.

[0096] All-solid-state secondary battery

[0097] In one embodiment, an all-solid-state secondary battery is provided, comprising: a positive electrode; a negative electrode; and the aforementioned solid electrolyte membrane positioned between the positive electrode and the negative electrode.

[0098] FIG. 1 is a cross-sectional view of an all-solid-state secondary battery according to an embodiment. Referring to FIG. 1, the all-solid-state secondary battery (100) may have a structure in which an electrode assembly in which a negative electrode (400) including a negative electrode current collector (401) and a negative electrode active material layer (403), a solid electrolyte membrane (300), and a positive electrode (200) including a positive electrode active material layer (203) and a positive electrode current collector (201) are laminated is housed in a battery case. The all-solid-state secondary battery (100) may further include an elastic layer (500) on the outer side of at least one of the positive electrode (200) and the negative electrode (400). Although FIG. 1 illustrates one electrode assembly including the negative electrode (400), the solid electrolyte membrane (300), and the positive electrode (200), an all-solid-state secondary battery may be manufactured by laminating two or more electrode assemblies.

[0099] anode

[0100] In one embodiment, a positive electrode current collector is provided, and a positive electrode active material layer formed on the positive electrode current collector. The positive electrode active material layer includes a positive electrode active material, and may further include a binder and / or a conductive material. Alternatively, the positive electrode active material layer may optionally further include a solid electrolyte, and the above-described description is equally applicable to the solid electrolyte included in the positive electrode active material layer.

[0101] positive electrode active material

[0102] The above-mentioned positive electrode active material may be applied without limitation as long as it is generally used in all-solid-state secondary batteries. For example, the above-mentioned positive electrode active material may use a compound capable of reversible intercalation and deintercalation of lithium, may include a lithium transition metal composite oxide, and may include a compound represented by any one of the following chemical formulas.

[0103] Li a A 1-b X b D2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5);

[0104] Li a A1-b X b O 2-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0105] Li a HAVE BEEN 1-b X b O 2-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0106] Li a HAVE BEEN 2-b X b O 4-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0107] Li a Ni 1-b-c Co b X c D α (0.90 ≤ a ≤1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.5, 0 <α ≤ 2);

[0108] Li a Ni 1-b-c Co b X c O 2-α T α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0109]

[0110] *103 Li a Ni 1-b-c Co b X c O 2-α T2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0111] Li a Ni 1-b-c Mr b X c D α(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2);

[0112] Li a Ni 1-b-c Mr b X c O 2-α T α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0113] Li a Ni 1-b-c Mr b X c O 2-α T2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0114] Li a Ni b HAVE BEEN c G d O2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1);

[0115] Li a Ni b Co c Mr d G e O2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤0.5, 0.001 ≤ e ≤ 0.1);

[0116] Li a NiG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0117] Li a CoG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0118] Li a Mr 1-b G b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0119] Li a Mn2G b O4(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0120] Li a Mn 1-g G g PO4(0.90 ≤ a ≤ 1.8, 0 ≤ g ≤ 0.5);

[0121] QO2; QS2; LiQS2;

[0122] V2O5; LiV2O5;

[0123] LiZO2;

[0124] LiNiVO4;

[0125] Li (3-f) J2(PO4)3(0 ≤ f ≤ 2);

[0126] Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2);

[0127] Li a FePO4(0.90 ≤ a ≤ 1.8).

[0128] In the above chemical formulas, A is selected from Ni, Co, Mn, or a combination thereof; X is selected from Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is selected from O, F, S, P, or a combination thereof; E is selected from Co, Mn, or a combination thereof; T is selected from F, S, P, or a combination thereof; G is selected from Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is selected from Ti, Mo, Mn, or a combination thereof; Z is selected from Cr, V, Fe, Sc, Y, or a combination thereof; J is selected from V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0129] The positive electrode active material may include, for example, lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium nickel cobalt oxide (NC), lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium nickel manganese oxide (NM), lithium manganese oxide (LMO), lithium iron phosphate oxide (LFP), or a combination thereof.

[0130] The positive electrode active material may include, for example, a lithium nickel-based oxide represented by the following chemical formula 2A, a lithium cobalt-based oxide represented by the following chemical formula 2B, a lithium iron phosphate-based compound represented by the following chemical formula 2C, a cobalt-free lithium nickel-manganese-based oxide represented by the following chemical formula 2D, or a combination thereof.

[0131] [Chemical Formula 2A]

[0132] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1

[0133] In the above chemical formula 2A, 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, 0≤z1≤0.7, 0.9≤x1+y1+z1≤1.1, and 0≤b1≤0.1, and M 1 and M 2 are each independently one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0134] In the above chemical formula 2A, 0.6≤x1≤1, 0≤y1≤0.4, and 0≤z1≤0.4, or 0.8≤x1≤1, 0≤y1≤0.2, and 0≤z1≤0.2.

[0135] [Chemical Formula 2B]

[0136] Lia2 Co x2 M 3 y2 O 2-b2 X b2

[0137] In the above chemical formula 2B, 0.9≤a2≤1.8, 0.7≤x2≤1, 0≤y2≤0.3, 0.9≤x2+y2≤1.1, and 0≤b2≤0.1, and M 3 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn and Zr, and X is one or more elements selected from the group consisting of F, P and S.

[0138] [Chemical Formula 2C]

[0139] Li a3 Fe x3 M 4 y3 PO 4-b3 X b3

[0140] In the above chemical formula 2C, 0.9≤a3≤1.8, 0.6≤x3≤1, 0≤y3≤0.4, and 0≤b3≤0.1, and M 4 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn and Zr, and X is one or more elements selected from the group consisting of F, P and S.

[0141] [Chemical Formula 2D]

[0142] Li a4 Ni x4 Mn y4 M 5 z4 O 2-b4 X b4

[0143] In the above chemical formula 2D, 0.9≤a2≤1.8, 0.8≤x4<1, 0 <y4≤0.2, 0≤z4≤0.2, 0.9≤x4+y4+z4≤1.1, 및 0≤b4≤0.1이고 M 5 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0144] The positive electrode active material may be in the form of particles, and the average particle diameter (D50) of the positive electrode active material may be from 1 μm to 25 μm, for example, from 3 μm to 25 μm, from 1 μm to 20 μm, from 1 μm to 18 μm, from 3 μm to 15 μm, or from 5 μm to 15 μm. For example, the positive electrode active material may include small particles having an average particle diameter (D50) of from 1 μm to 9 μm and large particles having an average particle diameter (D50) of from 10 μm to 25 μm. The positive electrode active material having such a particle diameter range can be harmoniously mixed with other components within the positive electrode active material layer and can realize high capacity and high energy density. Here, the average particle diameter may be obtained by selecting 20 or so random particles from a scanning electron microscope image of the positive electrode active material, measuring their particle diameters (diameter, major axis, or major axis length), obtaining a particle size distribution, and then taking the diameter (D50) of particles having a cumulative volume of 50% by volume from the particle size distribution as the average particle diameter.

[0145] The above-mentioned positive electrode active material may be in the form of a secondary particle formed by agglomeration of a plurality of primary particles, or may be in the form of a single particle. In addition, the above-mentioned positive electrode active material may be spherical or nearly spherical in shape, or may be polyhedral or irregular in shape.

[0146] Meanwhile, the positive electrode active material may include a buffer layer on the particle surface. The buffer layer may be expressed as a coating layer, a protective layer, etc., and may play a role in lowering the interfacial resistance between the positive electrode active material and the sulfide-based solid electrolyte particles. For example, the buffer layer may include a lithium-metal-oxide, wherein the metal may be one or more elements selected from the group consisting of Al, B, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ta, V, W, and Zr. The lithium-metal-oxide is excellent in lowering the interfacial resistance between the positive electrode active material and the solid electrolyte particles while improving the performance of the positive electrode active material by facilitating the movement of lithium ions and electron conduction.

[0147] The positive electrode active material may be included in an amount of 55 wt% to 99 wt% based on 100 wt% of the positive electrode active material layer, for example, 65 wt% to 95 wt%, or 75 wt% to 91 wt%.

[0148] bookbinder

[0149] The above binder serves to adhere positive electrode active material particles well to each other and also to adhere positive electrode active material well to a current collector, and representative examples thereof include, but are not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc.

[0150] The content of the binder in the positive electrode active material layer may be approximately 0.1 wt% to 5 wt% with respect to 100 wt% of the positive electrode active material layer.

[0151] Challenge

[0152] The above-described positive electrode active material layer may further include a conductive material. The conductive material is used to provide conductivity to the electrode, and any material that does not cause a chemical change and is electronically conductive in the battery to be formed may be used. Examples of conductive materials that may be used include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.; metal-based materials containing copper, nickel, aluminum, silver, etc. in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or conductive materials including mixtures thereof.

[0153] The content of the conductive material in the positive electrode active material layer may be 0 wt% to 3 wt%, 0.01 wt% to 2 wt%, or 0.1 wt% to 1 wt% with respect to 100 wt% of the positive electrode active material layer.

[0154] With respect to 100 wt% of the above positive electrode active material layer, the solid electrolyte may be included in an amount of 0.1 wt% to 35 wt%, for example, 1 wt% to 35 wt%, 5 wt% to 30 wt%, 8 wt% to 25 wt%, or 10 wt% to 20 wt%.

[0155] In addition, in the positive electrode active material layer, 65 wt% to 99 wt% of the positive electrode active material and 1 wt% to 35 wt% of the solid electrolyte may be included based on the total weight of the positive electrode active material and the solid electrolyte, for example, 80 wt% to 90 wt% of the positive electrode active material and 10 wt% to 20 wt% of the solid electrolyte may be included. When the solid electrolyte is included in the positive electrode in such an amount, the efficiency and life characteristics of the all-solid-state battery can be improved without reducing the capacity.

[0156] Aluminum foil may be used as the positive electrode collector, but is not limited thereto.

[0157] cathode

[0158] According to one embodiment, an anode for an all-solid-state secondary battery includes: an anode current collector; and an anode active material layer positioned on the anode current collector. The anode active material layer includes an anode active material and may further include a binder and / or a conductive material. Alternatively, the anode active material layer may optionally further include the solid electrolyte described above.

[0159] The above negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0160] The material capable of reversibly intercalating / deintercalating the lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0161] As the above lithium metal alloy, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, Sn or a combination thereof can be used.

[0162] As the material capable of doping and dedoping the lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used, and the Si-based negative electrode active material may be silicon, a silicon-carbon composite, or SiO. x(0 < x < 2), Si-Q alloy (wherein Q is an element selected from an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a Group 15 element, a Group 16 element, a transition metal, a rare earth element, or a combination thereof, and is not Si), Sn-based negative electrode active materials include Sn, SnO2, Sn-R alloy (wherein R is an element selected from an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a Group 15 element, a Group 16 element, a transition metal, a rare earth element, or a combination thereof, and is not Sn), and at least one of these may be mixed with SiO2 for use. The above elements Q and R may be selected from 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, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof.

[0163] For example, the negative active material may include silicon-carbon composite particles. The average particle diameter (D50) of the silicon-carbon composite particles may be, for example, 0.5 μm to 20 μm. The average particle diameter (D50) is measured by a particle size analyzer and refers to the diameter of particles having a cumulative volume of 50% by volume in a particle size distribution. With respect to 100 wt% of the silicon-carbon composite particles, silicon may be included in an amount of 10 wt% to 60 wt% and carbon may be included in an amount of 40 wt% to 90 wt%. The silicon-carbon composite particles may include, for example, a core including silicon particles and a carbon coating layer positioned on a surface of the core. The average particle diameter (D50) of the silicon particles in the core may be, for example, 10 nm to 1 μm, or 10 nm to 200 nm. The silicon particles may exist as silicon alone, in the form of a silicon alloy, or in an oxidized form. The oxidized form of silicon is SiO x (0 <x<2)로 표시될 수 있다. 또한, 상기 탄소 코팅층의 두께는 약 5 nm 내지 100 nm일 수 있다.

[0164] For example, the silicon-carbon composite particle may include a core including silicon particles and crystalline carbon, and a carbon coating layer located on the surface of the core and including amorphous carbon. For example, in the silicon-carbon composite particle, the amorphous carbon may not be present in the core but may be present only in the carbon coating layer. The crystalline carbon may be artificial graphite, natural graphite, or a combination thereof, and the amorphous carbon may be formed from coal pitch, mesophase pitch, petroleum pitch, coal oil, petroleum heavy oil, or a polymer resin (phenol resin, furan resin, polyimide resin, etc.). At this time, the content of the crystalline carbon may be 10 wt% to 70 wt%, and the content of the amorphous carbon may be 20 wt% to 40 wt% with respect to 100 wt% of the silicon-carbon composite particle.

[0165] In the above silicon-carbon composite particle, the core may include a void in the central portion. The radius of the void may be 30% to 50% of the radius of the silicon-carbon composite particle.

[0166] The silicon-carbon composite particles described above can effectively suppress problems such as volume expansion, structural collapse, or particle crushing due to charge and discharge, thereby preventing the phenomenon of conductive path disconnection, realizing high capacity and high efficiency, and are advantageous for use under high voltage or fast charging conditions.

[0167] The above Si-based negative electrode active material or Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material. When the Si-based negative electrode active material or Sn-based negative electrode active material and the carbon-based negative electrode active material are used in combination, the mixing ratio can be 1:99 to 90:10 by weight.

[0168] The content of the negative active material in the above negative active material layer may be 95 wt% to 99 wt% with respect to the total weight of the negative active material layer.

[0169] In one embodiment, the negative electrode active material layer further includes a binder and may optionally further include a conductive material. The content of the binder in the negative electrode active material layer may be 1 wt% to 5 wt% based on the total weight of the negative electrode active material layer. In addition, when the negative electrode active material layer further includes a conductive material, the negative electrode active material layer may include 90 wt% to 98 wt% of the negative electrode active material, 1 wt% to 5 wt% of the binder, and 1 wt% to 5 wt% of the conductive material.

[0170] The above binder serves to adhere the negative electrode active material particles well to each other and also to adhere the negative electrode active material well to the current collector. The binder may be a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof.

[0171] Examples of the non-aqueous binder include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or combinations thereof.

[0172] The above-mentioned aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0173] When using an aqueous binder as the above-mentioned negative electrode binder, a cellulose-based compound capable of imparting viscosity may be further included. The cellulose-based compound may be a mixture of one or more of carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may be Na, K, or Li.

[0174] The conductive material is used to provide conductivity to the electrode, and any material that does not cause chemical changes and is electronically conductive can be used in the battery. Examples of the conductive material include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials including copper, nickel, aluminum, and silver in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or conductive materials including mixtures thereof.

[0175] The negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, or a combination thereof.

[0176] precipitation cathode

[0177] As another example, the negative electrode for an all-solid-state secondary battery may be a precipitation-type negative electrode. The precipitation-type negative electrode may refer to a negative electrode that does not contain a negative electrode active material when the battery is assembled, but in which lithium metal or the like is precipitated or deposited on the negative electrode when the battery is charged, thereby acting as a negative electrode active material.

[0178] Fig. 2 is a schematic cross-sectional view of an all-solid-state secondary battery including a precipitation-type negative electrode. Referring to Fig. 2, the precipitation-type negative electrode (400') may include a negative electrode current collector (401) and a negative electrode coating layer (405) positioned on the negative electrode current collector. The all-solid-state secondary battery including the precipitation-type negative electrode (400') starts initial charging in a state in which no negative electrode active material is present. Subsequently, during charging, high-density lithium metal is precipitated or deposited between the negative electrode current collector (401) and the negative electrode coating layer (405), or on the negative electrode coating layer (405), to form a lithium metal layer (404), which may function as a negative electrode active material. Accordingly, in an all-solid-state secondary battery that has been charged more than once, a precipitation-type negative electrode (400') may include, for example, a negative electrode current collector (401), a lithium metal layer (404) positioned on the negative electrode current collector, and a negative electrode coating layer (405) positioned on the lithium metal layer. The lithium metal layer (404) refers to a layer in which lithium metal or the like is precipitated during the charging process of the battery, and may be referred to as a metal layer, a lithium layer, a lithium deposition layer, or a negative electrode active material layer.

[0179] The above cathode coating layer (405) may be referred to as a lithium electrodeposition induction layer or a cathode catalyst layer, and may include a lithium-philic metal, carbon material, or a combination thereof that acts as a catalyst.

[0180] The above-mentioned lithium-philic metal may include, for example, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, zinc, or a combination thereof, and may be composed of one type thereof or may be composed of several types of alloys. When the metal is present in the form of particles, the average particle diameter (D50) thereof may be about 4 μm or less, for example, 10 nm to 4 μm.

[0181] The carbon material may be, for example, crystalline carbon, amorphous carbon, or a combination thereof. The crystalline carbon may be, for example, natural graphite, artificial graphite, mesophase carbon microbeads, or a combination thereof. The amorphous carbon may be, for example, carbon black, activated carbon, acetylene black, Denka black, Ketjen black, or a combination thereof.

[0182] When the above-described negative electrode coating layer (405) includes both the metal and the carbon material, the mixing ratio of the metal and the carbon material may be, for example, a weight ratio of 1:10 to 2:1. In this case, the precipitation of lithium metal can be effectively promoted and the characteristics of the all-solid-state secondary battery can be improved. The negative electrode coating layer (405) may include, for example, a carbon material supported with a catalytic metal, or may include a mixture of metal particles and carbon material particles.

[0183] The above-described cathode coating layer (405) may include, for example, the above-described lithium-philic metal and amorphous carbon, in which case the precipitation of the lithium metal may be effectively promoted. As a specific example, the cathode coating layer (405) may include a composite in which a lithium-philic metal is supported on amorphous carbon.

[0184] The above cathode coating layer (405) may further include a binder, and the binder may be, for example, a conductive binder. In addition, the above cathode coating layer (405) may further include general additives such as fillers, dispersants, and ionic conductive agents.

[0185] The thickness of the cathode coating layer (405) may be, for example, 100 nm to 20 ㎛, or 500 nm to 10 ㎛, or 1 ㎛ to 5 ㎛.

[0186] The above-described precipitated negative electrode (400') may further include, for example, a thin film on the surface of the negative electrode current collector, that is, between the negative electrode current collector and the negative electrode coating layer. The thin film may include an element capable of forming an alloy with lithium. The element capable of forming an alloy with lithium may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, etc., and may be composed of one type thereof or may be composed of multiple types of alloys. The thin film may further planarize the precipitated form of the lithium metal layer (404) and further improve the characteristics of the all-solid-state secondary battery. The thin film may be formed by, for example, a vacuum deposition method, a sputtering method, a plating method, etc. The thickness of the thin film may be, for example, 1 nm to 500 nm.

[0187] The lithium metal layer (404) may include lithium metal or a lithium alloy. The lithium alloy may be, for example, 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, or a Li-Si alloy.

[0188] The thickness of the lithium metal layer (404) may be 1 µm to 500 µm, 1 µm to 200 µm, 1 µm to 100 µm, or 1 µm to 50 µm. Within the above range, the lithium storage layer can sufficiently perform its role and prevent performance degradation due to an increase in battery volume.

[0189] When such a precipitation-type cathode is applied, the cathode coating layer (405) can play a role in protecting the lithium metal layer (404) and suppressing the precipitation growth of lithium deadlight. Accordingly, short-circuiting and capacity reduction of the all-solid-state battery can be suppressed, and the life characteristics can be improved.

[0190] The above-mentioned all-solid-state secondary battery may be a unit cell having a structure of positive electrode / solid electrolyte membrane / negative electrode, a bi-cell having a structure of negative electrode / solid electrolyte membrane / positive electrode / solid electrolyte membrane / negative electrode, or a laminated battery in which the structure of the unit cell is repeated.

[0191] The shape of the above-mentioned all-solid-state secondary battery is not particularly limited, and may be, for example, coin-shaped, button-shaped, sheet-shaped, stacked, cylindrical, flat, etc. In addition, the above-mentioned all-solid-state secondary battery can be applied to large-sized batteries used in electric vehicles, etc. For example, the above-mentioned all-solid-state secondary battery can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). In addition, it can be used in fields requiring a large amount of power storage, and for example, it can be used in electric bicycles or power tools, etc. In addition, the above-mentioned all-solid-state secondary battery can be used in various fields such as portable electronic devices.

[0192] Hereinafter, examples and comparative examples of the present invention are described. The following examples are merely examples of the present invention, and the present invention is not limited to the following examples.

[0193] Example 1

[0194] 1. Preparation of porous silica nanoparticles

[0195] The average particle size (D50) is 200 nm, the average pore diameter is 4 nm, and the pore volume per unit mass is 0.1 cm 3 / g to 0.2 cm 3 Silica nanoparticles (748161 from Sigma Aldrich) of / g were prepared. At this time, the average particle diameter of the porous silica nanoparticles was measured by transmission electron microscope (TEM) images, and the average diameter of the pores and the volume per unit mass of the pores were measured by a BET (Brunauer-Emmett-Teller) device using a gas adsorption method.

[0196] 2. Manufacturing of additives for all-solid-state secondary batteries

[0197] 10 g of the aforementioned silica particles and 10 g of D-glucose were mixed, heated under vacuum to the melting point of D-glucose, and stirred for 5 hours. The mixture obtained as a result of the stirring was cooled to room temperature to solidify, and then a small amount of water and ethanol were added and centrifuged to wash away excess D-glucose. Subsequently, the product obtained by centrifugation was dried under vacuum at 60°C for 24 hours, thereby producing an all-solid-state secondary battery additive in which D-glucose is located within the pores of porous silica nanoparticles.

[0198] 3. Manufacturing of solid electrolyte membranes

[0199] Into an IBIB solvent, 3 wt% of the above-described additive, 2 wt% of an acrylic copolymer binder (SX-A334, Zeon), and 95 wt% of a solid electrolyte (Li6PS5Cl, D50=3.5㎛) were added and mixed to prepare a composition for a solid electrolyte membrane. The composition was applied onto a release PET film using a blade coater, pre-dried at about 50°C, and then dried at about 70°C under vacuum conditions to prepare a solid electrolyte membrane having a thickness of about 200㎛.

[0200] 4. Manufacturing of all-solid-state secondary batteries

[0201] An Ag / C composite was prepared by mixing carbon black having a primary particle size (D50) of approximately 30 nm and silver (Ag) having an average particle size (D50) of approximately 60 nm in a weight ratio of 3:1, and 0.25 g of the composite was added to 2 g of an NMP solution containing 7 wt% PVDF binder (Kureha #9300) and mixed to prepare a mixed solution. NMP was added little by little to the mixed solution and the mixed solution was stirred to prepare a slurry for a negative electrode coating layer. The prepared slurry was applied to a nickel foil current collector using a bar coater and vacuum-dried to prepare a deposition-type negative electrode in which a negative electrode coating layer was formed on the current collector.

[0202] LiNi coated with Li2O-ZrO2 0.8 Co 0.15 Mn 0.05 A cathode slurry was prepared by mixing 85 wt% of O2 cathode active material, 13.5 wt% of solid electrolyte Li6PS5Cl, 1.0 wt% of PVDF binder (Kureha #9300), and 0.5 wt% of carbon nanotube conductive material. The prepared cathode slurry was coated on an aluminum foil cathode current collector using a bar coater, and dried and rolled to prepare a cathode.

[0203] A solid electrolyte membrane was laminated on a cathode, and an anode was laminated thereon to manufacture a unit cell, which was then placed in a laminate film and subjected to warm isostatic pressing (WIP) at 80°C and 500 MPa for 30 minutes to manufacture an all-solid-state secondary battery.

[0204] Comparative Example 1

[0205] A solid electrolyte membrane and an all-solid-state secondary battery were manufactured in substantially the same manner as in Example 1, except that only the porous silica nanoparticles were used instead of the additive for an all-solid-state secondary battery when manufacturing the solid electrolyte membrane.

[0206] Evaluation Example 1: TEM Analysis

[0207] In order to confirm whether D-glucose is located inside the porous silica nanoparticles in the additive for an all-solid-state secondary battery, the additive manufactured in Example 1 and the porous silica nanoparticles manufactured in Comparative Example 1 were photographed and analyzed using a transmission electron microscope (TEM). FIGS. 4 and 6 show TEM photographs of the porous silica nanoparticles manufactured in Comparative Example 1, and FIGS. 5 and 7 show TEM photographs of the additive manufactured in Example 1.

[0208] By comparing FIG. 4 and FIG. 5, it can be seen that a partially dark area exists in FIG. 5, as indicated by an arrow, indicating that a solid electrolyte reactive compound is adsorbed and positioned within the pores of the porous silica nanoparticles.

[0209] In addition, through a comparison of FIGS. 6 and 7, it was obtained that the additive of FIG. 7 exhibited a darker color on average than the porous silica nanoparticles of FIG. 6, even though FIGS. 6 and 7 are average TEM images. Through this, it can be seen that, compared to the porous silica nanoparticles of Comparative Example 1, the additive of Example 1 has D-glucose, a solid electrolyte reactive compound, adsorbed and present within the porous silicon nanoparticles.

[0210] Evaluation Example 2: FT-NMR Analysis

[0211] In order to evaluate whether the shutdown function due to melting of the solid electrolyte reactive compound located within the pores under high-temperature conditions due to the temperature increase of the additive for an all-solid-state secondary battery is effective, an experiment was conducted in which 0.05 g of the additive prepared in Example 1 was dissolved in a DMSO-d6 solvent and heated to 150°C for 5 minutes. FT-NMR analysis was performed at initial (0 minutes), 3 minutes, and 5 minutes, and the results are shown in Fig. 8.

[0212] As shown in the results of Fig. 8, no peak was observed at the beginning of heating (0 minutes), indicating that the solid electrolyte reactive compound did not exist. However, as time passed, peaks indicating the existence of the solid electrolyte reactive compound, D-glucose, were observed after 3 and 5 minutes. In conclusion, in the case of the additive manufactured in Example 1, it was confirmed that the solid electrolyte reactive compound (D-glucose) located inside the pores of the porous silica nanoparticles at room temperature melted when heated to a high temperature of 100°C or higher, causing the solid electrolyte reactive compound, which is the internal substance, to melt out.

[0213] Evaluation Example 3: Evaluation of ionic conductivity before and after heating

[0214] An experiment was conducted in which the solid electrolyte membranes manufactured in Comparative Example 1 and Example 1 were heated at 180°C for 15 minutes, and the change in ionic conductivity before and after heating was measured, and the results are shown in Table 1 below. The ionic conductivity was measured through electrochemical impedance spectroscopy (EIS), and EIS was performed at an amplitude of approximately 10 mV, a frequency of 0.1 Hz to 106 Hz, in an air atmosphere, and at 25°C. At this time, the retention rate in Table 1 below was calculated using the following mathematical equation 1.

[0215] [Mathematical Formula 1]

[0216] Retention rate = [Ionic conductivity after heating / Ionic conductivity before heating] × 100

[0217] Preheating and post-heating retention rate comparison example 10.65 mS / cm 0.64 mS / cm 98.5 % Example 10.55 mS / cm 0.01 mS / cm 1.8 %

[0218] Referring to Table 1, in the case of Example 1, when heated to 180°C, the additive in the solid electrolyte membrane and the sulfide-based solid electrolyte reacted, inducing a shutdown, and thus successfully reducing the ionic conductivity. On the other hand, in the case of Comparative Example 1, even when the solid electrolyte membrane was heated to 180°C, the change in ionic conductivity was minimal, and thus a shutdown was not induced.

[0219] Although the preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts defined in the following claims also fall within the scope of the present invention.

[0220] Description of the symbol

[0221] 1: Porous silica nanoparticles 11: Pores

[0222] 2: Solid electrolyte reactive compound

[0223] 100: All-solid-state battery 200: Cathode

[0224] 201: Cathode current collector 203: Cathode active material layer

[0225] 300: solid electrolyte membrane 400: cathode

[0226] 401: Negative current collector 403: Negative active material layer

[0227] 400': Precipitation type cathode 404: Lithium metal layer

[0228] 405: Cathode coating layer 500: Elastic layer

Claims

1. Porous silica nanoparticles; and A solid electrolyte reactive compound positioned inside the pores of the porous silica nanoparticles; The above solid electrolyte reactive compound is an additive for an all-solid-state secondary battery having a melting point of 100°C to 170°C and including a heteroatom-containing functional group.

2. In paragraph 1, An additive for an all-solid-state secondary battery, wherein the heteroatom comprises sulfur, oxygen, nitrogen, or a combination thereof.

3. In paragraph 1, The above solid electrolyte reactive compound is an additive for an all-solid-state secondary battery, comprising 2 to 15 heteroatom-containing functional groups.

4. In paragraph 1, An additive for an all-solid-state secondary battery, wherein the hetero atom-containing functional group comprises a hydroxyl group, a salt of a hydroxyl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, a thiol group, a salt of a thiol group, an amino group, an amine group, a carbonyl group, a thiocarbonyl group, an ether group, a thioether group, an ester group, a thioester group, an aldehyde group, a carboxyl group, a salt of a carboxyl group, or a combination thereof.

5. In paragraph 1, An additive for an all-solid-state secondary battery, wherein the above heteroatom-containing functional group includes at least one oxygen-containing functional group.

6. In paragraph 1, An additive for an all-solid-state secondary battery, wherein the melting point of the solid electrolyte reactive compound is 133°C to 167°C.

7. In paragraph 1, An additive for an all-solid-state secondary battery, wherein the solid electrolyte reactive compound comprises an amide, a saccharide, an aliphatic organic acid, an aromatic organic acid, or a combination thereof, and has a melting point of 100°C to 170°C.

8. In paragraph 1, The above solid electrolyte reactive compound is an additive for an all-solid-state secondary battery including urea, thiourea, glucose, galactose, citric acid, salicylic acid, or a combination thereof.

9. In paragraph 1, The above solid electrolyte reactive compound is an additive for an all-solid-state secondary battery, which is D-glucose.

10. In paragraph 1, An additive for an all-solid-state secondary battery, wherein the average particle size of the above porous silica nanoparticles is 100 nm to 400 nm.

11. In paragraph 1, An additive for an all-solid-state secondary battery, wherein the average diameter of the pores is 1 nm to 20 nm.

12. In paragraph 1, The above solid electrolyte reactive compound is an additive for an all-solid-state secondary battery having a molecular weight of 30 g / mol to 900 g / mol.

13. In paragraph 1, An additive for an all-solid-state secondary battery, wherein the solid electrolyte reactive compound is contained in an amount of 10 to 90 wt% based on 100 wt% of the additive.

14. In paragraph 1, An additive for an all-solid-state secondary battery, wherein the porous silica nanoparticles are contained in an amount of 10 to 90 wt% based on 100 wt% of the additive.

15. In paragraph 1, The volume of pores per unit mass of the above porous silica nanoparticles is 0.01 cm 3 / g to 1 cm 3 / g additive for all-solid-state secondary batteries.

16. A mixture is obtained by mixing a solid electrolyte reactive compound into porous silica nanoparticles, The mixture is heated to a temperature higher than the melting point of the solid electrolyte reactive compound, and then cooled to solidify, Including separating and drying the solidified result, A method for producing an additive for an all-solid-state secondary battery, wherein the solid electrolyte reactive compound has a melting point of 100° C. to 170° C. and includes a heteroatom-containing functional group.

17. In paragraph 16, A method for producing an additive for an all-solid-state secondary battery, wherein the mixing ratio of the porous silica nanoparticles and the solid electrolyte reactive compound is 10:90 to 90:10 by weight.

18. In paragraph 16, A method for producing an additive for an all-solid-state secondary battery, wherein the heating is performed at a temperature higher than the melting point of the solid electrolyte reactive compound and +50° C. or lower relative to the melting point of the solid electrolyte reactive compound.

19. In paragraph 16, A method for producing an additive for an all-solid-state secondary battery, wherein the above heating is performed for 1 to 10 hours.

20. In paragraph 16, A method for producing an additive for an all-solid-state secondary battery, wherein the above heating is performed under a vacuum atmosphere.

21. In paragraph 16, A method for producing an additive for an all-solid-state secondary battery, wherein the above drying is performed at a temperature of 50°C to 100°C.

22. In paragraph 16, A method for producing an additive for an all-solid-state secondary battery, wherein the above drying is performed for 1 to 50 hours.

23. A solid electrolyte membrane comprising a solid electrolyte; and an additive for an all-solid-state secondary battery according to any one of claims 1 to 15.

24. In paragraph 23, The above solid electrolyte is a solid electrolyte membrane which is a sulfide-based solid electrolyte.

25. In paragraph 24, The above sulfide-based solid electrolyte is a solid electrolyte membrane including an argyrodite-type sulfide represented by the following chemical formula 1. [Chemical Formula 1] (Li a M 1 b M 2 c )(P d M 3 e )(S f M 4 g )X h In the above chemical formula 1, 4≤a≤8, M 1 is Mg, Cu, Ag, or a combination thereof, and 0≤b<0.5, M 2 is Na, K, or a combination thereof, and 0≤c<0.5, M 3 is Sn, Zn, Si, Sb, Ge, or a combination of these, and 0 <d<4, 0≤e<1 이고, M 4 is O, SO n , or a combination thereof, and 1.5≤n≤5, 3≤f≤12, 0≤g<2, X is F, Cl, Br, I, or a combination thereof, and 0≤h≤2.

26. In paragraph 23, A solid electrolyte membrane in which the above-mentioned all-solid-state secondary battery additive is contained in an amount of 1 to 15 wt% based on 100 wt% of the solid electrolyte.

27. In paragraph 24, A solid electrolyte membrane wherein the above sulfide-based solid electrolyte is in the form of particles and the average particle diameter of the particles is 0.1 ㎛ to 5.0 ㎛.

28. Bipolar; cathode; and An all-solid-state secondary battery comprising a solid electrolyte membrane according to claim 23 positioned between the positive electrode and the negative electrode.

29. In paragraph 28, The above cathode is Negative current collector; and An all-solid-state secondary battery comprising: a negative electrode coating layer positioned on the negative electrode current collector and including a lithium-philic metal, a carbon material, or a combination thereof.

30. In paragraph 29, An all-solid-state secondary battery further comprising a lithium metal layer formed by charging between the negative electrode current collector and the negative electrode coating layer.

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