KR20210105505A - All-Solid-State Lithium Secondary Batteries Having Solid Electrolyte-infiltrated Polymeric Support and Method for Fabricating the Same - Google Patents

Abstract

In the present disclosure, disclosed are an all-solid lithium secondary battery having a solid electrolyte layer, in which a sulfide-based solid electrolyte is impregnated in a porous polymer support, interposed between a cathode and an anode; and a method for manufacturing the same. According to the present invention, all-solid lithium secondary battery can be implemented in a simple manner.

Description

All-Solid-State Lithium Secondary Batteries Having Solid Electrolyte-infiltrated Polymeric Support and Method for Fabricating the Same

The present disclosure relates to an all-solid lithium secondary battery using a polymer support impregnated with a solid electrolyte and a manufacturing method thereof. More specifically, the present disclosure relates to an all-solid lithium secondary battery having a solid electrolyte layer impregnated with a porous polymer support in which a sulfide-based solid electrolyte is impregnated between a cathode and an anode, and a method for manufacturing the same.

As small electronic devices and electric vehicles are widely used, interest in secondary batteries having high energy density is increasing. Lithium ion secondary batteries using lithium ions as secondary batteries are expanding their application fields from small mobile device power sources to mid- to large-sized electric vehicles (e.g., EV, HEV, etc.) and energy storage device (ESS) power sources. is in trend In particular, interest in electric vehicles, which are eco-friendly vehicles, is very high, and major automakers around the world are accelerating the development of related technologies by recognizing electric vehicles as the next-generation growth technology under the motto of eco-friendliness.

In the case of such a medium and large-sized lithium ion secondary battery, unlike a small one, the operating environment (eg, temperature and impact) is harsh, and since it includes a large number of batteries, it is essential to secure safety. As the industrial field requiring lithium ion secondary batteries expands the application range to large batteries, interest in the safety issues of lithium ion secondary batteries is also greatly increased.

In the case of a conventional lithium ion secondary battery, since a non-aqueous electrolyte in which a lithium salt is dissolved in an organic solvent, that is, an organic liquid electrolyte, is used, there are phenomena such as low thermal stability, ignition, and leakage of liquid electrolyte, so strict packaging is required. Therefore, there is a technical limit in which it is difficult to increase the energy density above a certain level. In fact, as explosion accidents of products to which lithium-ion secondary batteries are applied are continuously reported, it is necessary to solve these safety-related problems.

In order to solve the problems caused by the liquid electrolyte described above, all-solid-state lithium ion secondary batteries using a solid electrolyte made of an inorganic material, which is a non-combustible material, are emerging as an alternative. It is known that a sulfide, an oxide, or the like can be used as a solid electrolyte for an all-solid-state lithium ion secondary battery.

Among these inorganic solid electrolytes, a sulfide-based solid electrolyte is considered as a potential material that can actually be commercialized because it can form a good interface through cold pressing due to its high ionic conductivity and deformable properties. In particular, compared to other solid electrolytes, it is possible to exhibit high lithium ion conductivity while having a small amount.

In this regard, sulfide-based solid electrolytes of various compositions have been developed. For example, in Korean Patent No. 1392689, lithium (Li), M (eg, Ge and P), and sulfur (S) containing A sulfide-based solid electrolyte material, and Korean Patent Publication No. 2016-0032664 includes at least sulfur and lithium, phosphorus (P), silicon (Si), boron (B), aluminum (Al), germanium (Ge), Disclosed is a sulfide-based solid electrolyte further comprising at least one selected from zinc (Zn), gallium (Ga), indium (In) and a halogen element. In addition, Korean Patent No. 1506109 discloses a sulfide-based solid electrolyte containing Li, A (A is at least one of P, Si, Ge, Al and B), X (X is a halogen) and S, and have.

In the case of a conventional all-solid-state battery using a sulfide-based solid electrolyte, in general, an electrode (cathode or anode) is prepared by dry mixing an electrode active material and a solid electrolyte, a solid electrolyte is disposed thereon, and then another electrode ( After arranging the anode or cathode), it is manufactured by a dry method of pressing and integrating. However, the dry method has limitations in terms of mass production, and the contact between the particles between the electrode active material and the solid electrolyte in the electrode is not smooth. In addition, when the dry method is applied, the solid electrolyte layer is formed to a thickness exceeding approximately 500 μm, which is undesirable in terms of energy density, and therefore it is required to make the solid electrolyte layer thin.

In order to solve the above problems, a wet method of forming an overcoat on the electrode layer by preparing a solid electrolyte slurry, or casting is also known (eg, Energy Environ. Sci., 2019, 12, 938-944). However, it is not easy to overcast uniformly over a large area during the commercialization process, and in particular, a phenomenon in which the solid electrolyte and the electrode layer are mixed with each other may be induced.

Accordingly, there is a need to solve the problems of the prior art described above.

According to one embodiment of the present disclosure, an all-solid-state lithium secondary battery having a thin-film solid electrolyte structure having good properties (eg, high crystallinity) is provided by solving the problems of the prior art. .

According to another embodiment of the present disclosure, an object of the present disclosure is to provide a method for manufacturing an all-solid-state lithium secondary battery that is easy to mass-produce and can exhibit smooth contact or interface characteristics between an electrode and a solid electrolyte.

According to the first aspect of the present disclosure,

preparing a solid electrolyte solution by dissolving a sulfide-based solid electrolyte capable of a solution process in a solvent;

Separately, forming a pre-laminate or assembly comprising a cathode, a porous polymer support and an anode;

impregnating the laminate with a solid electrolyte solution to fill the pores of the porous polymer support with a solid electrolyte; and

heat-treating the laminate filled with the solid electrolyte;

includes,

wherein the porous polymer support has a porosity of at least 60% and a thickness of 5 to 150 μm, and

The heat treatment step is performed at at least 200 ℃ to form a solid electrolyte having increased crystallinity is provided a method of manufacturing an all-solid-state lithium secondary battery.

According to an exemplary embodiment, in the step of impregnating the solid electrolyte solution, the solid electrolyte solution may be impregnated into at least one of the cathode and the anode as well as the pores of the porous polymer support in the laminate.

According to an exemplary embodiment, the porous polymer support is polyimide, polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyamide, polytetrafluoroethylene (PTFE), polysulfone (PSF), At least one material selected from the group consisting of polyether ketone (PEK) and polyether ether ketone (PEEK) may be provided.

According to an exemplary embodiment, the sulfide-based solid electrolyte may be represented by the following general formula 1:

[General formula 1]

Li _6-m PS _5-m X _1+m

In the above formula, X is at least one halogen element selected from the group consisting of Cl, Br and I,

m is 0 to 1.

According to an exemplary embodiment, the porous polymer support may be a polyimide material represented by the following Chemical Formula 1:

[Formula 1]

In the above formula, n is a polymerization degree of 500 to 10000.

According to an exemplary embodiment, the sulfide-based solid electrolyte may have a lithium argyrodite crystal structure.

According to a second aspect of the present disclosure,

An all-solid-state lithium secondary battery comprising a laminate in which a cathode, a solid electrolyte layer, and an anode are stacked,

The solid electrolyte layer includes (i) a porous polymer support and (ii) a sulfide-based solid electrolyte filled in pores of the porous polymer support,

wherein the porous polymer support has a porosity of at least 60% and a thickness of 5 to 150 μm, and

An all-solid-state lithium secondary battery having a crystallinity of at least 60% of the filled sulfide-based solid electrolyte is provided.

The all-solid-state lithium secondary battery according to an embodiment of the present disclosure has a problem of poor interfacial contact between the electrode and the solid electrolyte layer, which has been pointed out in the conventional dry method of forming a solid electrolyte, specifically, a sulfide-based solid electrolyte layer, or on the electrode as a wet method It is possible to effectively solve problems such as the difficulty of increasing the area pointed out in the coating or overcasting method, and to implement an all-solid-state lithium secondary battery in a simple manner.

Furthermore, since the solid electrolyte can be implemented with a thinner thickness compared to the conventional dry method, the battery performance per unit volume can be increased, which is suitable for commercialization. Since the solid electrolyte can be stably maintained without causing melting, defects such as internal short circuits can be suppressed. Therefore, a wide range of applications is expected in various fields such as batteries for electric vehicles and energy storage devices in the future.

1 is a view showing a process of impregnating (or permeating) the members constituting the laminate by pouring a solution of a sulfide-based solid electrolyte into a laminate of a cathode/porous polymer support/anode according to an exemplary embodiment;
2 is a diagram schematically illustrating a series of processes for preparing a porous support by an electrospinning method in Example, and permeating or impregnating it with a solid electrolyte solution to prepare a sulfide-based solid electrolyte membrane (sample);
3 is an FTIR spectrum of the electrospun PI membrane in the Example;
4 is _{a characterization result of Li 6} PS ₅ Cl _1-x Br _x by solution process (a) 30 for _{Li 6} PS ₅ Cl _1-x Br _x subjected to solution process and heat-treated at 180° C. and 400° C. Lithium ion (Li ⁺ ) conductivity at °C, and (b) powder XRD results _{of Li 6} PS ₅ Cl _1-x Br _x subjected to solution process and heat-treated at 400 °C;
Figure 5 is the result of characterization of the electrospun polyimide nonwoven fabric (PI NW) and _{the PI membrane impregnated with Li 6} PS ₅ Cl _1-x Br _x heat-treated at 400 ° C. (a, b) electrospun porous PI Photograph and SEM photograph of the nonwoven fabric (the sheet is 10 × 10 cm 2 in Fig. 5a), (c) TGA profile of the porous PI nonwoven fabric electrospun under Ar flow, (d, e) PI-Li ₆ PS ₅ Cl _0.5 Br _0.5 Photograph of the membrane, (f) _{SEM photograph of the PI-Li 6} PS ₅ Cl _0.5 Br _0.5 membrane, (g) PEI-Li ₆ PS ₅ Cl _0.5 Br _0.5 membrane and conventional Li ₆ PS ₅ Cl _{0.5 heat treated at 180° C.} Conductance and conductivity of lithium ions (Li ⁺ ) of PI-Li ₆ PS ₅ Cl _0.5 Br _0.5 membranes versus Br _0.5 pellets, and (h) PI-Li ₆ PS ₅ Cl _0.5 Br _0.5 membranes A cross-sectional SEM photograph of , and a diagram showing the corresponding EDXS mapping of sulfur and chlorine;
6 is a Nyquist plot (30° C.) of PI-LPSClBr and PEI-LPSClBr via impedance analysis;
7 is a photograph of each of (a) electrospun PEI membrane, and (b) Li ₆ PS ₅ Cl _0.5 Br _0.5 -permeated PEI membrane (PEI-LPSClBr) (heat treatment temperature of PEI-LPSClBr is 180° C.) );
8 is a graph showing the results of linear fitting of the DC polarization curve of PI-LPSC1Br;
9 is a test result of an NCM/LTO all-solid-state whole cell using a PI (or PEI)-Li ₆ PS ₅ Cl _0.5 Br _0.5 membrane, (a) NCM showing _{a PI-Li 6} PS ₅ Cl _0.5 Br _{0.5 layer;} /PI-Li ₆ PS ₅ Cl _0.5 Br _0.5 /LTO cross-sectional SEM photograph and corresponding elemental map of the all-solid cell, (b) NCM/PI-Li ₆ PS ₅ Cl _0.5 Br _0.5 /LTO all-solid full cell and NCM /PEI-Li ₆ PS ₅ Cl _0.5 Br _0.5 /LTO first cycle charge-discharge voltage profile at 30° C. of each of the all-solid-state all-cells, and (c) the corresponding rate capability;
10 is a PI-Li ₆ PS ₅ Cl _0.5 as a test result of the all-solid whole cells using a Br _{0.5 membranes, (a) PI-Li 6} PS 5 Cl 0.5 Br _0.5 membrane a NCM / graphite all-solid whole cell having a _{PI-Li 6} PS ₅ Cl _0.5 Br _0.5 membrane before and after the first 2 cycle charge-discharge voltage profile at 0.1 C and 30° C. and (b) corresponding cycling performance, (c) before and after exposure to 180° C. for 1 h. a NCM / graphite around the solid charge in 0.1 C and 30 ℃ the whole cell having a - full discharge voltage profile, (d) existing research and PI-Li ₆ PS ₅ Cl _0.5 by NCM / graphite former having a Br _0.5 membrane solid As a result of comparing the solid electrolyte (SE) membrane thickness and capacity for the battery, (e) the corresponding first cycle charge-discharge voltage profile at 0.05C and 70°C;
11 is a photograph showing the change with the heat treatment temperature of PEO-LiTFSI containing 10% by weight of alumina before and after high temperature (180°C and 400°C) exposure;
12 is a graph showing the results of analyzing the particle size according to the solvent of the liquefied sulfide-based solid electrolyte using Dynamic Light Scattering (DLS) equipment;
13 is a Raman spectroscopy analysis result of _{Li 6} PS ₅ Cl dissolved in ethanol;
14 is a Raman spectroscopy analysis result of _{Li 6} PS ₅ Cl before and after solution process; and
15 is a Raman spectroscopy analysis result of LCO/Li ₆ PS _{5 Cl-ethanol solution.}

The present invention can all be achieved by the following description. It is to be understood that the following description describes preferred embodiments of the present invention, but the present invention is not necessarily limited thereto. In addition, the accompanying drawings are provided to aid understanding, the present invention is not limited thereto, and details regarding individual configurations may be properly understood by the specific purpose of the related description to be described later.

"All-solid-state secondary battery" may mean a secondary battery in which a cathode, an anode, and an electrolyte are made of a solid together, and the electrolyte is largely an organic (polymer)-based battery based on a polymer (eg, polyethylene oxide, etc.) It can be divided into a solid secondary battery and an inorganic all-solid-state secondary battery based on Li-PS.

"Solid electrolyte" means a solid electrolyte capable of moving ions therein, and since it is a solid in a normal state, it is not usually dissociated or liberated into cations and anions. _{Therefore, it is also distinguished from electrolyte salts (LiPF 6} , LiBF ₄ , LiFSI, LiCl, etc.) in which cations and anions are dissociated or liberated in an electrolyte or polymer.

“Sulphide-based solid electrolyte” is a kind of inorganic solid electrolyte, and may mean that it contains sulfur (S) and has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table.

"Argyrodite" or "argyrodite crystal" may refer to a crystal structure or a crystal bonding arrangement, wherein the crystal structure or bonding arrangement is of the formula Ag ₈ Silver _{characterized by GeS 6} is a natural mineral that is a germanium sulfide mineral based on the crystal structure of azirodite.

"Cathode" and "anode" respectively refer to the electrode of the battery. In the charging cycle of a lithium secondary battery, Li ions are separated from the cathode and move to the anode through the electrolyte, while electrons are transferred from the cathode to the anode through an external circuit. move to On the other hand, in the discharge cycle, Li ions pass through the electrolyte and move from the anode to the cathode, while electrons leave the anode and move to the cathode via an external circuit.

"Nanofiber" may mean a fiber having a nanoscale micro-thickness or diameter in a narrow sense, but in a broad sense it can be understood as a concept including a fiber having a thickness of several μm or less, specifically 5 μm or less. .

"Polyimide" is broadly defined as a polymer formed by condensation reaction of a polymer containing an imide ring in its main chain, specifically an organic anhydride or dianhydride with diamine, in which case a thermal dehydration reaction (curing reaction) is followed by a subsequent thermal dehydration reaction (curing reaction). can be performed with In this case, the "imidization reaction" may involve the step of forming a cyclic polyimide through dehydrogenation of the polyamic acid.

"Electrospinning" may refer to a method of continuously manufacturing nanofibers or webs having a diameter of several micrometers to several tens of nanometers by applying a high voltage to a polymer solution or melt. The principle of the electrospinning process is that when an electric field is applied to the polymer solution, an electrostatic repulsive force is generated on the surface of the polymer solution. It forms a conical droplet shape called a Taylor cone. After that, when the strength of the electric field overcomes the surface tension of the polymer solution, the solution is emitted in the form of a fiber from the nozzle and collected or accumulated in a collector. can

"Heat treatment" refers to intentionally subjecting an entire object or a part thereof to a heat cycle (which may also include a temperature change over time), and, if necessary, a desired specific structure and physical properties (or changes) ) may involve chemical or additional physical treatment to achieve

It may be understood that the expressions “on” and “on” are used to refer to the concept of relative position. Accordingly, not only the case where other components are directly present in the mentioned layers, but also at least one other component or additional component may be interposed or present therebetween. Similarly, the expressions "under", "under" and "below" and the expressions "between" may also be understood as relative concepts with respect to the position.

When any component or member is described as being “connected” or “in communication with” another component or member, unless otherwise stated, as well as being directly connected or in communication with the other component or member. , it may be understood that the case where they are connected or communicated under the intervening of other components or members is also included.

When a component is "included", it means that other components and/or steps may be further included unless otherwise specified.

According to one embodiment of the present disclosure, a solid electrolyte solution is prepared by dissolving a solid electrolyte in a solvent instead of a method of separately preparing and stacking the cathode, the solid electrolyte and the anode constituting the all-solid lithium secondary battery, and then the porous A method of preparing a solid electrolyte by impregnating the pores of a polymer support is adopted. Specifically, all-solid lithium 2 using a sulfide-based solid electrolyte capable of a solution process (specifically, a sulfide-based solid electrolyte that can be liquefied or solutionable using a predetermined solvent) and impregnated with a porous polymer support with a solution of the solid electrolyte It can be used as a solid electrolyte in the structure of a secondary battery. In this way, by applying the solution process using the porous support, the performance per unit volume of the battery can be significantly improved by forming a solid electrolyte layer with a significantly thinner thickness than in the prior art, and also in the overcasting or overcoating method. It is possible to suppress the problem of mutual mixing between the solid electrolyte and the electrode layer.

1 is a process of impregnating (or permeating) a member constituting the preliminary laminate by pouring a solution of a sulfide-based solid electrolyte into a preliminary laminate or assembly including a cathode/porous polymer support/anode according to an exemplary embodiment; show

According to an exemplary embodiment, a preliminary laminate or assembly 100 including a cathode 101, a porous polymer support 103, and an anode 102 is manufactured, and then a sulfide-based solid electrolyte solution 104 is poured into the porous Wet (impregnate or impregnate) the polymeric support 103 . As a result, the solid electrolyte is impregnated or infiltrated into the pores formed in the porous polymer support 102 and filled. At the same time, the solid electrolyte solution penetrates into the interfacial region between the porous polymer support 103 and the electrode, that is, the cathode and the anode 101 and 102, so that a smooth contact between the solid electrolyte layer and the electrode can be made. That is, by penetrating the solid electrolyte solution into pores or voids existing at or near the interface formed on the cathode and/or the anode, it is possible to effectively suppress the phenomenon of poor contact between the solid electrolyte layer and the electrode.

Porous Polymer Support

According to the illustrated embodiment, the porous polymer support 103 has (i) good mechanical strength, (ii) high porosity, (iii) small pore size, and (iv) lithium ion (Li ⁺ ) conductivity in a subsequent step. It may be required to have high thermal stability so as to be able to withstand the high-temperature heat treatment performed to increase the temperature and to eliminate safety-related risks even under harsh environments.

First, it is necessary to have a relatively high level of porosity in order to provide a space capable of holding a sufficient amount of a sulfide-based solid electrolyte. Illustratively, the porosity of the porous polymer support 103 may be, for example, at least about 60%, specifically at least about 65%, and more specifically about 70 to 90%. In this regard, if the porosity is too low, it is impossible to support a sufficient amount of the solid electrolyte, whereas if the porosity is too high, the mechanical strength, etc. may be weakened, so it may be advantageous to adjust it within the above-mentioned range. . However, the numerical range may be changed depending on the material of the polymer support and the like.

In addition, the porous polymer support 103 may be made of a material having good thermal stability, for example, the melting point of the polymer support 103 is, for example, at least about 200 ° C., specifically at least about 250 ° C., more specifically may represent about 300 to 500 °C. In this regard, when the melting point of the polymer is less than a certain level, it may be contracted, deformed, or melted under heat treatment conditions for improving the crystallinity of the solid electrolyte performed in a subsequent step due to deterioration in thermal stability, thereby causing an internal short circuit. Accordingly, it may be advantageous to use a species having the aforementioned melting point range.

In addition, as the porous polymer support 103 serves as a scaffold capable of holding the sulfide-based solid electrolyte, it may be advantageous to have a pore size suitable for effectively penetrating the solid electrolyte solution and supporting the solid electrolyte. Illustratively, the average pore size may range, for example, from about 0.01 to 10 μm, specifically from about 0.05 to 5 μm, and more specifically from about 0.1 to 2 μm. When the pore size is less than or exceeding a certain level, it may be advantageous to adjust the pore size within the above-described range as it may be difficult to uniformly penetrate or support the solid electrolyte throughout the porous polymer support.

According to an exemplary embodiment, the porous polymer support 103 may have a thickness of, for example, about 5 to 150 μm, specifically about 10 to 100 μm, and more specifically about 20 to 80 μm. In this regard, it should be noted that the thickness of the solid electrolyte layer in the conventional all-solid-state battery exceeds about 500 μm, but as in this embodiment, a thin and flexible porous support is used, and the sulfide-based solid electrolyte permeates or If the supporting method is adopted, it is possible to implement a thin solid electrolyte layer. As a result, the performance of the all-solid-state battery can be improved by shortening the diffusion path of lithium ions and reducing the volume of the solid electrolyte.

In addition, when a polar solvent is used as a solvent used in a sulfide-based solid electrolyte solution, the porous polymer support may have an affinity for a polar solvent that can be easily wetted by the polar solvent. Accordingly, in a specific embodiment, the porous support may be made of a polymer material having a polar functional group. In this case, the polar functional group is alcohol, amine. It may be at least one selected from ketones, ethers, and the like.

According to an exemplary embodiment, when the porous polymer support 103 is in the form of a nonwoven fabric or a web, individual fibers constituting the same may be nanofibers, and the diameter thereof is, for example, about 100 to 1000 nm, specifically about 200 to 700 nm, more specifically, may be in the range of about 300 to 600 nm. The above-described diameter range may be understood as an example, and may be changed in consideration of mechanical strength, porosity, and the like.

Further, in an exemplary embodiment, the density of the porous polymer support 103 is, for example, about 0.7 to 2 g/cm 3 , specifically about 0.9 to 1.8 g/cm 3 , and more specifically about 1.1 to 1.5 g/cm 3 can be a range.

In addition, the porous polymer support 103 may advantageously exhibit insulation, that is, low electrical conductivity, in order to minimize the effect of leakage current or self-discharge, illustratively its conductivity is about 10 ^-8 S/cm or less, Specifically, it may be in the range of about 10 ^-9 S/cm or less, more specifically about 10 ^-12 to 10 ^{-9 S/cm.}

In consideration of the above points, the material of the porous polymer support 102 is, for example, polyimide, polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyamide, polytetrafluoroethylene (PTFE). ), polysulfone (PSF), polyether ketone (PEK) and polyether ether ketone (PEEK) may be at least one selected from the group consisting of. According to a specific embodiment, the polymer support may be a polyimide (PI) material, in particular, may be in the form of a non-woven fiber or a web. Hereinafter, polyimide will be mainly described.

According to an exemplary embodiment, the porous polymer support may be a polyimide material represented by the following Chemical Formula 1:

[Formula 1]

In the above formula, n may range from about 500 to 10000 (specifically, about 1000 to 5000, more specifically about 2000 to 4000) as the degree of polymerization.

This polyimide exhibits excellent thermal stability, making it possible for the sulfide-based solid electrolyte to undergo solution processing to perform high temperature (for example, up to about 400° C.) heat treatment required to achieve good conductivity, which is PEO (melting point). : about 65°C), in contrast to conventional polymers with limited thermal stability.

As an example, the above-described polyimide may be synthesized according to Scheme 1 below.

[Scheme 1]

According to an exemplary embodiment, the porous support 102 made of polyimide may be prepared by methods known in the art, for example, melt-blown spinning, conjugate spinning, electrospinning, wet spinning, etc. (wet-spinning), etc. may be applied. According to a specific embodiment, the porous support can be manufactured by an electrospinning method, which is advantageous because when the electrospinning method is adopted, the porosity can be increased and thin fibers having a diameter of several hundred nanometers can be manufactured. can

The above-mentioned porous polymer support may use a commercially available product, or alternatively, a polyimide nonwoven fabric or a web structure may be manufactured using an electrospinning method. The manufacturing method of such an electrospinning method may be described as follows.

The electrospinning process can be largely divided into a jet forming step, a stretching step, and a solidification step from the jet to nanofibers. At this time, between two electrodes having opposite polarities, one pole of the electrode is located on the spinning nozzle and the other pole on the collector, the charged spinning material is discharged into the air through the spinneret (or spinning nozzle) (spinning) And, it is possible to manufacture a microfine fiber by drawing a charged filament in the air or by branching the filament. More specifically, after the solution is charged by directly applying a voltage of (+) or (-) to the spinnerette or the spinning nozzle, the charged solution is discharged to the air layer through the spinnerette, and then the charged filaments in the air layer Nanofibers can be produced by stretching and another filament branching. The ejection filaments charged to (+) through the application of a (+) voltage, or the ejection filaments charged to (-) through the application of a (-) voltage, are generated between adjacent filaments in the electric field formed between the radiating part and the collector. It may be made microscopic due to electrical influences such as repulsion. The microfine filaments formed as described above may be accumulated on a grounded collector or a collector charged with a polarity opposite to that of the charged filaments to be manufactured in the form of a nonwoven fabric or a web.

In this regard, in the electrospinning process, the (+) voltage and the (-) voltage may be appropriately selected according to the polymer material and the solvent. In addition, in the electrospinning process, the thickness of the fiber can be determined by the applied voltage per distance, the solution discharge amount, and the size of the spinneret, and the applied voltage can be adjusted according to the distance between the collector and the spinneret, for example, about It is adjustable in the range of 5 to 30 kV, specifically about 10 to 20 kV, more specifically about 13 to 17 kV. In addition, the distance between the collector and the spinneret may be adjusted, for example, in the range of about 10 to 30 cm, specifically, about 12 to 25 cm, and more specifically, about 15 to 20 cm. The above-described electrospinning conditions may be understood as illustrative.

In addition, the spinning solution can be prepared in the form of dissolving a polyimide precursor in an organic solvent, and as in Scheme 1, a fiber assembly is prepared by electrospinning using a polyimide precursor having solubility in an organic solvent. And it can be imidized. According to an exemplary embodiment, the polyimide precursor may typically be a polyamic acid, and the polyamic acid may be prepared from an aliphatic or aromatic tetracarboxylic dianhydride and an aliphatic or aromatic diamine. In this regard, aliphatic or aromatic tetracarboxylic dianhydride is, for example, cyclobutane tetracarboxylic dianhydride, pyromellitic dianhydride, 1,2,3,4-benzene tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride , bis(dicarboxyphenyl ether) dianhydride, bis(dicarboxyphenylsulfone) dianhydride, bis(dicarboxyphenylsulfide) dianhydride, bis(dicarboxyphenyl)propane dianhydride, bis(dicarboxyphenyl)hexafluoropropane It may be at least one selected from dianhydride, biphenyl tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, and the like. In addition, diamines are, for example, aromatic and aliphatic diamines, in particular p-phenylene diamine, m-phenylene diamine, diamino diphenyl ether, diamino diphenyl sulfone, diamino diphenyl sulfide, diamino benzophenone, It may be at least one selected from bis(aminophenyl)propane, bis(aminophenyl)hexafluoropropane, diaminobiphenyl, diaminopyridine, diaminonaphthalene, and the like.

As solvents in spinning solution: m-cresol, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), acetone, diethyl acetate, tetra At least one selected from hydrofuran (THF), chloroform, gamma-butyrolactone, and the like may be used. In this case, the concentration of the polyamic acid in the spinning solution may be, for example, about 1 to 30% by weight, specifically about 2 to 25% by weight, more specifically about 5 to 20% by weight, but this is an exemplary It can be understood to the purpose, and can be adjusted in consideration of the degree of formation of an appropriate fiber structure, the degree of increase in the discharge pressure, and the like.

Thereafter, an imidation reaction may be subsequently performed, and the imidization reaction may be performed in a manner such as alone or in combination with heat treatment, chemical treatment, and the like.

According to an exemplary embodiment, a process of forming a porous polyimide support by imidizing the nonwoven fabric or web of precursor fibers through heat treatment may be performed. In this case, it is possible to have an imidization rate as high as possible, for example, at least about 80%, specifically about 85 to 99%, more specifically about 90 to 99%. If the imidization rate is less than a certain level, it may be difficult to ensure good thermal stability, or it may be dissolved by a solvent when in contact with a solid electrolyte solution, so it may be advantageous to adjust it to have the above-mentioned range. However, the numerical range may be understood as an example. The heat treatment temperature for the above-described imidization reaction may be, for example, about 200 to 500 °C, specifically about 250 to 450 °C, more specifically about 300 to 420 °C. silver, for example, can be adjusted in a range of about 1 to 10 hours, specifically about 2 to 8 hours, and more specifically about 3 to 6 hours.

Sulfide-based solid electrolyte

According to one embodiment, the sulfide-based solid electrolyte may advantageously have a composition capable of a solution process, and may be of a type capable of penetrating or supporting the pores or pores of the porous polymer support because it is miscible with a solvent. To this end, it may be advantageous for the sulfide-based solid electrolyte to be maintained below a predetermined particle size in a liquid medium. Illustratively, the sulfide-based solid electrolyte may be a type having a particle size of about 1 μm or less, specifically about 0.1 μm or less, and more specifically about 0.01 μm or less in a liquid medium.

According to an exemplary embodiment, the sulfide-based solid electrolyte may have an azirodite crystal structure and may be represented by the following general formula (1).

[General formula 1]

Li _6-m PS _5-m X _1+m

In the above formula, X is at least one halogen element selected from the group consisting of Cl, Br and I,

m is 0 to 1 (specifically 0 to 0.8, more specifically 0 to 0.5).

Such a sulfide-based solid electrolyte has solubility in a solvent (a specific solvent), and thus has the advantage that it can be applied in the form of a solution.

According to a specific embodiment, the sulfide-based solid electrolyte may be represented by the following general formula (2).

[General Formula 2]

Li ₆ PS ₅ Cl _1-x Br _x (0<x<1, specifically 0.2<x<0.8, more specifically 0.4<x<0.6)

As described above, better ionic conductivity can be provided by introducing a plurality of halogen elements.

According to an exemplary embodiment, the sulfide-based solid electrolyte may have various shapes, for example, particle shapes such as spherical and elliptical spherical shapes may be exemplified. In addition, the average particle diameter of the sulfide-based solid electrolyte may be, for example, about 0.1 to 50 μm, specifically about 1 to 30 μm, and more specifically about 5 to 20 μm.

Also, illustratively, the lithium ion conductivity (30° C.) of the sulfide-based solid electrolyte is, for example, at least about 0.5 mS/cm, specifically at least about 1 mS/cm, more specifically about 1.5 to 3 mS/cm cm range.

In addition, the sulfide-based solid electrolyte may have a cubic crystal structure having main peaks at 2θ values of 25 to 26° and 29.5 to 30.5° in XRD analysis.

According to one embodiment of the present disclosure, the sulfide-based solid electrolyte according to Chemical Formula 1 may be prepared by the procedure exemplified below.

In general, a raw material containing lithium, phosphorus (P), elemental sulfur and element X (element halogen) is first prepared as follows.

- lithium element

Elemental lithium may be provided from lithium sources known in the art, typically sulfides thereof (Li ₂ S, Li ₂ S ₈ , Li ₂ S ₆ , Li ₂ S ₄ , Li ₂ S ₂ , Li ₂ S or a combination thereof), specifically Li ₂ S, and more specifically, it may be advantageous to use _{high purity Li 2} S that does not contain impurities as much as possible. In addition to the above-described lithium sulfide-based source, the use of a form combined with other elements constituting the sulfide-based solid electrolyte compound, for example, LiCl, LiBr, LiI, etc., is not excluded, but a source in which lithium and sulfur are combined (specifically As Li ₂ S) does not contain oxygen, it may be preferable as a source of elemental lithium.

- Phosphorus (P)

In one embodiment, as a source of phosphorus (P), a phosphorus-containing compound known in the art may be used. According to an exemplary embodiment, as the phosphorus-containing compound, for example _{, a sulfide form such as phosphorus sulfide (P 2} S ₅ ) may be used, and in addition, a halogen-phosphorus compound (eg, PI ₅ , PCl ₅ , PBr) _5, etc.) can be used.

- sulfur

According to exemplary embodiments, elemental sulfur may be provided alone (ie, in the _{form of elemental sulfur (S 8} )) or in combination with other elements (eg, lithium and/or phosphorus). Specific examples of such a sulfur source, as described above, will be omitted. However, a desired elemental sulfur content may be achieved by selectively adding a sulfur source comprising elemental sulfur alone (ie elemental sulfur).

- X element

In this embodiment, halogen (ie, at least one of Cl, Br and I) may be used alone as the halogen source, and alternatively, other elements in the sulfide-based solid electrolyte (eg, lithium and/or phosphorus) and may be provided in a combined form. Examples of the halogen source of this type, as described above, will be omitted.

According to one embodiment, each of the above-mentioned raw materials may be prepared in an amount corresponding to the stoichiometric ratio of the sulfide-based compound represented by Formula 1.

Then, as described above, the source of the element corresponding to the general formula 1 is added in an appropriate amount in consideration of the desired ratio (that is, the ratio between the elements specified in the general formula 1), and the reaction between the raw materials is carried out while grinding and mixing it. By induction, a reaction product in powder form (including element lithium, elemental phosphorus, elemental sulfur and element X) is formed.

At this time, the grinding/mixing process may be typically performed under an inert atmosphere. In this case, in order to form an inert atmosphere, for example, helium, neon, argon, or a mixed gas thereof may be used, and more typically argon gas can be used. The reason for performing the grinding/mixing step under an inert atmosphere as described above is that, when grinding and mixing in the atmosphere, oxygen may be mixed and oxides may be partially generated in the final product.

According to an exemplary embodiment, in the grinding/mixing process, a mechanical milling (specifically, high-energy mechanical milling) method may be used, and all of the above-mentioned raw material sources may be put into a grinding device at once for milling, and either A plurality of raw material sources may be first added and pulverized, and then the remaining raw material sources may be added sequentially or additionally to be milled. At this time, the temperature in the milling process is not particularly limited, but may be, for example, about 10 to 50° C., specifically about 15 to 45° C., and more specifically about 20 to 40° C. In the case of the aforementioned mechanical milling method, since it can be performed under relatively mild temperature conditions such as room temperature, there is an advantage in that thermal decomposition of the raw material does not occur.

As such, a reaction product in powder form is formed by reacting the prepared raw material while pulverizing and mixing, and this reaction product is a compound containing lithium element, phosphorus element, sulfur element and X element, and can exhibit both glassy and crystallinity. have.

According to an exemplary embodiment, since the heating (heat treatment) step may also be performed under an inert atmosphere, a crystalline sulfide-based solid electrolyte may be finally obtained through heat treatment. In this case, the first heat treatment temperature may be, for example, exceeding about 150°C and up to 800°C, specifically about 400 to 700°C, and more specifically about 50 to 600°C. In addition, the heating (heat treatment) time, for example, may be selected within the range of about 1 to 20 hours, specifically, about 3 to 15 hours, and more specifically, about 5 to 10 hours.

The above-described heat treatment conditions can be suitably adjusted so that the sulfide-based compound formed has a single crystal, for example, first about 200 to 400° C./h (specifically about 250 to 350° C./h, more specifically about 290 to about 290° C./h). The temperature is maintained after raising the temperature to the heat treatment temperature at a heating rate of 310°C/h), and then a constant cooling rate (eg, about 200 to 400°C/h, specifically about 250 to 350°C/h, more specifically to about 290 to 310 °C / h) can be carried out in a manner that is cooled to room temperature.

According to one embodiment, as much as the above-described sulfide-based solid electrolyte compound can exhibit relatively good solubility in a solvent (specifically, a specific solvent), it can be dissolved in a solvent to prepare it in a solution form.

According to an exemplary embodiment, a solid electrolyte solution is prepared by combining a sulfide-based solid electrolyte compound with a solvent. At this time, the solution may be prepared under stirring or in the absence of stirring, but it may be advantageous to perform stirring to prepare a uniform solution. In addition, the mixing time may be, for example, about 0.5 to 15 hours, specifically about 1 to 10 hours, more specifically about 2 to 5 hours, but this may be understood as an exemplary meaning.

In an exemplary embodiment, the solvent usable for preparing the solid electrolyte solution may be a polar solvent, and the polarity index is, for example, about 4 to 6, specifically about 4.2 to 5.7, more specifically It can be selected from the kind having a requirement of about 4.8 to 5.5, and can be used alone or in combination.

According to an exemplary embodiment, as such a solvent, for example, an alcohol (specifically, an aliphatic alcohol having 1 to 4 carbon atoms), an amine solvent. A ketone-based solvent, an ether-based solvent, etc. may be used, and may be used alone or in the form of a mixture. According to a specific embodiment, as the solvent, for example, ethanol may be used, and more specifically, absolute ethanol may be used.

Meanwhile, according to an exemplary embodiment, the concentration of the solid electrolyte in the solid electrolyte solution may be, for example, about 0.1 to 1 M, specifically about 0.2 to 0.5 M, more specifically about 0.3 to 0.4 M.

The concentration of the solid electrolyte can be adjusted depending on the type of solvent, etc. At an excessively high concentration, it may be difficult to easily penetrate into the pores of the porous polymer support due to insufficient dissolution or excessive viscosity, whereas at an excessively low concentration, subsequent drying To the extent that solvent loss or excessive energy input may be required, or adhesion or support of the solid electrolyte may be insufficient, it may be advantageous to appropriately adjust within the above-described range. However, the above-described concentration range may be understood as an example.

Fabrication of all-solid-state lithium-ion secondary battery

According to one embodiment, as shown in FIG. 1 , a preliminary laminate or assembly 100 including a cathode 101 , a porous polymer support 103 and an anode 102 may be formed, and based on this Thus, an all-solid-state lithium ion secondary battery can be manufactured. The configuration of such an all-solid-state lithium ion secondary battery is known in the art, and components other than the solid electrolyte can be briefly described as follows.

First, the cathode 101 to which the cathode active material layer is attached, the anode 102 to which the anode active material layer is attached, and the above-described porous polymer support 103 is interposed between the cathode active material layer and the anode active material layer. A pre-laminate or assembly may be formed with this method.

Then, the process of impregnating the above-described sulfide-based solid electrolyte solution may be performed. In this process, the solid electrolyte solution may penetrate the porous polymer support 103 in the laminate as a whole and fill the pores in the support. At the same time, it can also penetrate into each of the positive active material layer of the cathode 101 and the negative active material layer of the anode 102, as a result of which an empty space or gap is formed at the interface between the porous support-based solid electrolyte layer and the cathode and the anode. Formation can be suppressed as much as possible, and the sulfide-based solid electrolyte can form a smooth contact with each of the positive electrode active material and the negative electrode active material. Through this solution process, an all-solid-state lithium secondary battery can be easily manufactured, which is advantageous in terms of compatibility.

According to an exemplary embodiment, it is preferable that the positive active material be capable of reversibly intercalating and releasing lithium ions. The material of such a positive electrode active material is not particularly limited, and may be a transition metal oxide or an element capable of complexing with Li such as sulfur. Among them, a transition metal oxide can be used, and one or more elements selected from Co, Ni, Fe, Mn, Cu and V can be exemplified as such a transition metal element.

Examples of the transition metal oxide include a transition metal oxide having a layered rock salt structure, a spinel-type transition metal oxide, a lithium-containing transition metal phosphate compound, a lithium-containing transition metal halide phosphate compound, and a lithium-containing transition metal silicon compound. can

In this regard, as a transition metal oxide having a layered rock salt structure, LiCoO ₂ (LCO), LiNi ₂ O ₂ , LiNi _0.85 Co _0.10 Al _0.05 O ₂ (NCA), LiNi _0.33 Co _0.33 Mn _0.33 O ₂ (NMC), LiNi _0.5 Mn _0.5 O can be exemplified. Examples of the spinel-type transition metal oxide include LiCoMnO ₄ , Li ₂ FeMn ₃ O ₈ , Li ₂ CuMn ₃ O ₈ , Li ₂ CrMn ₃ O ₈ , and Li ₂ NiMn ₃ O ₈ . Further, examples of the lithium-containing transition metal phosphate compound may include LiFePO ₄ , Li ₃ Fe ₂ (PO ₄ ) ₃ , LiFeP ₂ O ₇ , LiCoPO ₄ , and Li ₃ V ₂ (PO ₄ ) ₃ , and lithium As the -containing transition metal halide phosphoric acid compound, for example, Li ₂ FePO ₄ F, Li ₂ MnPO ₄ F, Li ₂ CoPO ₄ F, and the like can be exemplified. In addition, as the lithium-containing transition metal silicon compound, for example, Li ₂ FeSiO ₄ , Li ₂ MnSiO ₄ , Li ₂ CoSiO ₄ and the like can be exemplified. Each of the above-described positive active materials may be used alone or in combination of two or more.

According to an exemplary embodiment, the positive electrode active material may be in the form of particles, wherein the particle size is, for example, about 1 to 10 μm, specifically about 2 to 5 μm, more specifically about 3 to 7 μm. have.

In the case of the anode active material, it is preferable that lithium ions can be inserted and released reversibly. The material of the negative electrode active material is not particularly limited, and examples thereof include a carbonaceous material, a metal oxide such as tin oxide or silicon oxide, a metal composite oxide, lithium or a lithium alloy. More specifically, a carbonaceous material or lithium composite oxide (eg, LTO (Li ₄ Ti ₅ O ₁₂ ), TiO ₂ , SiO _x , SnO _x , CuO _x VO _x , In ₂ O _{3 ,} etc.) may be used. .

In this regard, the carbonaceous material is a material substantially composed of carbon, for example, petroleum pitch, carbon black such as acetylene black (AB), natural graphite (or graphite), artificial graphite such as vapor-grown graphite, and PAN ( A carbonaceous material obtained by calcining various synthetic resins such as polyacrylonitrile)-based resin and furfuryl alcohol resin can be exemplified. In addition, various carbon fibers such as PAN-based carbon fibers, cellulosic carbon fibers, pitch-based carbon fibers, vapor-grown carbon fibers, lignin carbon fibers, glassy carbon fibers, activated carbon fibers, and flat graphite can be exemplified.

In addition, as the metal oxide and the metal composite oxide, an amorphous oxide may be used, and a chalcogenide, which is a reaction product of a metal element and an element of Group 16 of the periodic table, may also be used. In the compound consisting of such an amorphous oxide and a chalcogenide, an amorphous oxide of a semimetal element or a chalcogenide may be used, and more specifically, one of Al, Ga, Si, Sn, Ge, Pb, Sb, and Bi. Oxides and chalcogenides consisting of single or a combination thereof may be used, for example, Ga ₂ O ₃ , SiO, GeO, SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₂ O ₄ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , Bi ₂ O ₃ , Bi ₂ O ₄ , SnSiO ₃ , GeS, SnS, SnS ₂ , PbS, PbS ₂ , Sb ₂ S ₃ , Sb ₂ S ₅ , SnSiS ₃ , or the like can be used.

In an exemplary embodiment, the negative active material may be in the form of particles, wherein the particle size may range, for example, from about 0.5 to 20 μm, specifically from about 1 to 15 μm, and more specifically from about 3 to 12 μm. have.

According to an exemplary embodiment, after impregnating the solid electrolyte solution, the cathode active material layer (eg LiCoO ₂ ) and the negative electrode active material layer of the anode (eg Li ₄ Ti ₅ O ₁₂ ) in each of the solid electrolyte The content of may be, for example, about 5 to 30% by weight, specifically about 8 to 27% by weight, more specifically about 10 to 25% by weight.

Meanwhile, since the all-solid-state lithium ion secondary battery may include a current collector, an electron conductor may be used as a material of the current collector. In the case of the current collector of the positive electrode, aluminum, stainless steel, nickel, titanium, etc. may be used, and in addition, carbon, nickel, titanium, or silver treated with carbon, nickel, titanium or silver may be used on the surface of aluminum or stainless steel. On the other hand, as the current collector of the negative electrode, aluminum, copper, stainless steel, nickel, titanium, or the like can be used. The shape of the current collector may be typically a film shape, but a mesh structure, a punching structure, a porous body, a foam, and the like may be applied. Illustratively, the thickness of the current collector may be in the range of, for example, about 1 to 300 μm, specifically about 10 to 250 μm, and more specifically about 50 to 200 μm, but this may be understood as an exemplary meaning.

As described above, after impregnating the solid electrolyte solution in the preliminary laminate or assembly, a heat treatment or heating step may be performed.

After the impregnation process is performed as described above, the solvent contained in the laminate or assembly may be removed (eg, vaporized) to form a dried structure. Illustratively, in the drying step, a drying method known in the art (eg, vacuum drying, heat drying, etc.) may be applied. In this case, the drying conditions may be, for example, about 80 to 200° C. (specifically, about 100 to 150° C.), and a vacuum or an inert atmosphere (eg, argon).

On the other hand, as a subsequent step, a step of subsequently heat-treating or heating the dried laminate or assembly may be performed. This heating step removes the residual solvent in the structure as completely as possible and at the same time the crystallinity of the sulfide-based solid electrolyte in the structure. It is performed to further increase the ionic conductivity by increasing the

According to an exemplary embodiment, the heat treatment temperature may be selected, for example, in the range of at least about 200 °C, specifically about 250 to 500 °C, more specifically about 300 to 400 °C, and the heating time is, for example, It may range from about 1 to 10 hours, specifically from about 3 to 6 hours. Other conditions may be appropriately adjusted within the conditions of the heat treatment step mentioned in relation to the preparation of the sulfide-based solid electrolyte. In addition, the atmosphere gas during heating may be, for example, an inert gas such as argon (Ar), and may alternatively be performed under vacuum.

According to an exemplary embodiment, after performing the heat treatment or heating step, the content of the sulfide-based solid electrolyte in the solid electrolyte layer (ie, the membrane in which the sulfide-based solid electrolyte is supported on the porous polymer support) is, for example, about 60 to 95 weight. %, specifically about 65 to 90% by weight, more specifically about 70 to 80% by weight.

According to an exemplary embodiment, the crystallinity of the sulfide-based solid electrolyte in the structure (laminate or assembly) after performing the heat treatment or heating step is, for example, at least about 60%, specifically at least about 70%, more specifically at least about 80%. %, which is increased compared to the point where the crystallinity of the sulfide-based solid electrolyte in the laminate or assembly before heat treatment or heating is in the range of about 20 to 60%, specifically about 30 to 50%. However, the crystallinity range may be understood as an example.

According to an exemplary embodiment, as described above, the conductivity (30° C.) of the solid electrolyte layer (that is, a form in which a sulfide-based solid electrolyte is permeated or supported on a porous polymer support) is, for example, at least about 0.001 mS/cm, specifically about 0.005 to 0.5 mS/cm, more specifically about 0.01 to 0.3 mS/cm, particularly specifically about 0.05 to 0.25 mS/cm.

In addition, the areal mass of the solid electrolyte layer may be, for example, in the range of about 2 to 15 mg/cm 2 , specifically about 3 to 10 mg/cm 2 , and more specifically about 5 to 8 mg/cm 2 . .

According to an exemplary embodiment, in the all-solid lithium secondary battery, as described above, the solid electrolyte layer in which the sulfide-based solid electrolyte is impregnated or permeated into the pores or pores of the porous support is interposed between the cathode and the anode, and furthermore, the solid On the opposite side to the electrolyte layer, components of a conventional all-solid-state lithium secondary battery known in the art, such as a current collector, may be included. In this regard, in the case of an all-solid-state battery having a solid electrolyte layer according to this embodiment, the energy density is, for example, about 50 to 200 Wh kg _cell ^-1 , specifically about 80 to 150 Wh kg _cell ^-1 , More specifically, it may be in the range of about 100 to 120 Wh kg _cell ⁻¹ , which may be understood as an example, and may be changed according to other factors such as a cathode and an anode constituting the battery.

In addition, according to an exemplary embodiment, the above-described all-solid-state lithium secondary battery exhibits stable cycling performance, so that even when charge-discharge is performed over a long period of time, the deterioration of the battery performance is at a low level. For example, at least about 80%, specifically, at least about 85% of the initial battery capacity may be maintained even after 100 cycles are performed.

Hereinafter, preferred examples are presented to help the understanding of the present invention, but the following examples are only provided for easier understanding of the present invention, and the present invention is not limited thereto.

Example

- _{Preparation of Li 6} PS ₅ Cl _1-x Br _x (0 ≤ x ≤ 1)

_{Li 2} S (99.9%, Alfa Aesar) through a zirconia vial (80 mL) and a ball (10 mm in diameter) using a Planetary Ball Mill (Pulverisette 7PL; Fritsch GmbH) at 600 rpm for 10 hours _{, Li 6} PS ₅ Cl _1-x Br _x by ball milling a stoichiometric mixture of , P ₂ S ₅ (99%, Sigma-Aldrich), LiCl (99.9%, Alfa Aesar) and LiBr (99.9%, Alfa Aesar) (0 ≤ x ≤ 1) was prepared. Ball milled Li ₆ PS ₅ Cl _1-x Br _x powder was dissolved in absolute ethanol (99.5%, Sigma-Aldrich) at a concentration of 150 mg/mL to form a uniform solid electrolyte solution useful for the permeation process. After evaporating ethanol under room temperature and vacuum conditions, heat treatment was performed at 180° C. or 400° C. for 6 hours to obtain solution processable Li ₆ PS ₅ Cl _1-x Br _x powder.

For the slurry process, ball milled Li ₆ PS ₅ Cl _1-x Br _x (LPSClBr) powder was annealed at 550° C. for 6 hours. As a scaffold for a solid electrolyte membrane, polyamic acid (PAA) synthesized using pyromellite dianhydride (PMDA, 97% Sigma Aldrich) and 4,4'-oxydianiline (ODA, 97% Sigma Aldrich) monomers was used. A polyimide nonwoven fabric (PI NW) was produced by imidization reaction.

The PAA precursor was synthesized by polymerization of PMDA and ODA monomers (equimolar ratio) with dehydrated dimethylacetamide (DMAc) at 0°C. After 4 hours of reaction, a clear PAA solution was obtained and used for electrospinning.

To prepare polyetherimide (PEI), PEI (Ultem 1000) was dissolved in a mixed solvent of DMAc/NMP at 70° C. for 12 hours to prepare a 23 wt% PEI solution. PAA and PEI membranes were prepared by electrospinning using the respective solutions. The detailed experimental conditions of the electrospinning process were as follows: a feed rate of 3.5 μL/min and an applied voltage of 13 kV (for PAA), a feed rate of 4.5 μL/min and an applied voltage of 15 kV (for PEI), and the distance from the nozzle: 15 cm. The thus-prepared PAA was imidized with PI through the following step-by-step thermal curing process under a nitrogen gas atmosphere: (i) 60 °C for 30 minutes, (ii) 120 °C for 30 minutes, (iii) for 1 hour 200° C., (v) 300° C. for 1 hour, and (iv) 400° C. for 10 minutes.

- Preparation of electrodes and solid electrolyte membranes

A series of processes for preparing a sulfide-based solid electrolyte sample by an impregnation method using the nonwoven fabric prepared by the electrospinning method in this example is shown in FIG. 2 .

Impregnation with LPSClBr was performed by dropping the solid electrolyte solution onto the electrospun PI or PEI membrane. After evaporating the solvent in an Ar-filled glove box, heat treatment was performed at 400° C. under Ar atmosphere for PI and at 180° C. under vacuum conditions for PEI. The resulting solid electrolyte membrane is denoted as "PI-LPSClBr" and "PEI-LPSClBr", respectively.

To prepare oxide-polymer electrolytes (OPCs), all precursors were dried under vacuum (60 °C for PEO and 100 °C for lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and alumina). ). LiTFSI (99.95%, Sigma-Aldrich), PEO (M _w : about 600,000, Sigma-Aldrich) and Al ₂ O ₃ (< 50 nm, Sigma-Aldrich) were added to acetonitrile (99.8%, Sigma-Aldrich). Then, mechanical stirring was performed at 50° C. for 10 hours. The [EO]/[Li] ratio was 16:1, and the weight fraction of alumina in the total amount of PEO and LiTFSI was 10% by weight. The mixture was cast on a polytetrafluoroethylene plate using a doctor blade method, and then dried at 50°C. In order to completely remove the solvent, an additional heat treatment was performed at 60° C. for 5 hours under vacuum. Active material (LiNi _0.6 Co _0.2 Mn _0.2 O ₂ (NCM)) or graphite (Gr) or Li ₄ Ti ₅ O ₁₂ (LTO)), Li ₆ PS ₅ Cl _0.5 Br _0.5 , nitrile-butadiene rubber (NBR), and A slurry was prepared by mixing the carbon additive (NCM622 and LTO only) in anhydrous xylene (or dibromomethane for LTO). For LTO electrodes, a small amount of solvent ionic liquid (Li(G3)TFSI (equimolar mixture of triethyleneglycol dimethyl ether (G3) and LiTFSI) was added. For NCM, Gr and LTO electrodes, the electrode composition was each 70:27.5:1.0:1.5, 58.6:39.1:1.5:0.0, and 49.1:45.1:1.0:1.5:3.5 (Li(G3)TFSI) The slurry mixture was transferred to a current collector (Al and Ni by a doctor blade method). Foil (only for Gr)), then heat treated at 120° C. (or 60° C. for LTO electrode) For mass loading of active material, 8.5 mg/for each of NCM, graphite and LTO cm 2 , 6.0 mg/cm 2 , and 12.6 mg/cm 2 .

A conventional LIB electrode used in the solid electrolyte permeation process was also prepared by the slurry process. For the slurry, the active material (LiCoO ₂ (LCO) or LTO), polyvinylidene fluoride (PVDF) and carbon additive are mixed in weight fractions of 97:1:2 and 80:10:10 for LCO and LTO respectively. prepared. The electrode thus prepared was combined with the electrospun porous PI NW to form an LCO/PI/LTO assembly, which was then used in the solid electrolyte permeation process.

Characterization

- Characterization of substances

For XRD measurement, the solid electrolyte was sealed with a beryllium window and mounted on a MiniFlex 600 diffractometer (Rigaku Corp.) (Cu Ka radiation: 1.5406 ㅕ) at 40 kV and 15 mA. Fourier transform infrared spectroscopy (FTIR) spectra of PI were obtained using a Bruker Alpha FTIR spectrometer with attenuated total reflection modes between ^{4000 cm -1} and 500 cm ^{-1 .} In order to evaluate the thermal stability of PEI and PI, TGA was performed under an Ar atmosphere and in a temperature range of 40 to 800 °C. A cross-section of a solid electrolyte membrane non-solid-state full cell was prepared by polishing using an Ar ion beam (JEOL, IB19510CP) at 5 kV for 6 hours. SEM images and corresponding EDXS element mapping were obtained using JSM-7610FPlus (JEOL).

- Analysis of electrochemical properties

The conductivity of the lithium ions was measured by the AC impedance method using a Ti/(SE pellet or SE membrane)/Ti symmetric cell with Li-ion blocking properties. The solid electrolyte powder and the solid electrolyte membrane were cold-pressed at 550 MPa. The electronic conductivity of the solid electrolyte membrane was measured by DC polarization using a Ti/SE membrane/Ti symmetric cell. The all-solid-state cell was pressurized to 550 MPa at room temperature after placing NCM and Gr (or LTO) electrodes on each side of the solid electrolyte membrane.

The galvanostatic charge-discharge test was performed at 30° C. with a voltage range of 2.0-4.2 V and 1.3-2.7 V for the NCM/Gr full cell and the NCM/LTO full cell, respectively. The LCO/LTO full cell prepared by the solid electrolyte permeation process was cycled at 30°C with a voltage range of 1.3-2.7 V. An external pressure of 70 MPa was applied during operation.

Results and discussion

3 shows the results of confirming the functional group of polyimide (PI) by FTIR. Referring to the figure ^{, asymmetric C = O stretching at 1775 cm -1} , symmetric C = O stretching at 1720 cm ^-1 , and An absorption band for CN stretching was identified at 1375 cm ^{−1 .} Moreover, ^{no absorption band was observed for NH stretching in the range of 3300-3500 cm -1} , indicating that the polyamic acid was completely converted to PI by the thermal imidization reaction.

_{On the other hand, it was suitable for absorbing a sufficient amount of liquid Li 6} PS ₅ [Cl,Br] as a high porosity and interconnected fiber structure was formed through the electrospinning process. Due to the high affinity between ethanol and the polar imide group in PI, a uniform Li ₆ PS ₅ [Cl,Br]-EtOH solution could penetrate into the electrospun porous polymer nonwoven fabric by simple dropping. Subsequent evaporation of the solvent under vacuum _{induced crystallization of the initial Li 6} PS ₅ [Cl,Br] and increased the crystallinity through further heat treatment at a temperature higher than about 180°C. Then densified by cold pressed under 550 MPa, the final _{Li 6 PS 5 [Cl, Br} ] - the resulting bar, hayeotneun obtain a penetration PI membrane _{PI-Li 6 PS 5 [Cl} , Br] The membrane of the non-woven fabric of polymeric material Its thickness could be controlled by adjusting the thickness and/or the amount of the solid electrolyte solution. Polyetherimide (PEI), which exhibits lower thermal stability compared to PI, was also selected as an electrospun nonwoven fabric (NW) as a control.

In the case of solid electrolyte coating and LIB electrode penetration technology by the conventional wet method, heat treatment is limited to 200° C. or less, because of the risk of reaction between the solid electrolyte and the electrode active material, and thermal decomposition of the PVDF binder. However, since the heat treatment temperature of 200 DEG C is insufficient to obtain a high degree of crystallinity, it is difficult to achieve a high lithium ion conductivity exceeding ^{10 -3 S/cm.} As a result of the analysis, the reactivity between the solid electrolyte and the PI polymer was not serious under elevated temperature conditions, and PI could extend the applicable heat treatment temperature to 400°C. This makes it possible to increase the lithium ion conductivity of the solution-processable solid electrolyte. Moreover, _{based on the effect of halide in Li 6} PS ₅ X (X=Cl, Br, I) on the migration of lithium ions, heat treated at 400° C., solution-processable lithium azirodite, i.e. Li ₆ PS ₅ Cl _1-x Br _x (0 ≤ x ≤ 1) can be optimized.

_{The lithium ion conductivity of solution-processable Li 6} PS ₅ Cl _1-x Br _x heat-treated at 180° C. or 400° C. according to x was measured by AC method using a Ti/SE/Ti symmetrical cell at 30° C. was measured, and the results are shown in FIG. 4A. Specifically, FIG. 4A shows the change in ionic conductivity according to the heat treatment temperature and x.

According to the figure, upon heat treatment at 180° C., Li ₆ PS ₅ X (Li ₆ PS ₅ Cl (x=0) or Li ₆ PS ₅ Br (x=1.0)) containing a single halogen element is 0.1-0.2 The lithium ion conductivity was shown in the mS/cm range. When a plurality of halogen elements were used (eg, Li ₆ PS ₅ Cl _0.5 Br _0.5 ), the lithium ion conductivity was increased to 0.4 mS/cm. ^{However, the lithium ion conductivity of 10 −4} S/cm of the sulfide-based solid electrolyte for penetration is too low to be applied to the polymer-solid electrolyte composite, which means that the insulating polymer component is approximately single-digit with respect to the final film structure. This is because it lowers the lithium ion conductivity (ie, ≤10 ^-5 S/cm). It should be noted that when the heat treatment temperature was raised to 400° C., the lithium ion conductivity was significantly increased. This can be attributed to the increase in crystallinity and the removal of organic impurities. In particular, the highest lithium conductivity (2.0 mS/cm) was obtained in a composition containing a plurality of halogen elements. The achievement of optimal lithium ion conductivity in Li ₆ PS ₅ Cl _0.5 Br _0.5 can be explained by the interaction between the polarizability of the anion backbone and the X ⁻ /S ^{2-site disorder, which} change the pre-factor and the activation barrier, respectively.

_{4b shows a powder XRD pattern of solution-processed Li 6} PS ₅ Cl _1-x Br _x (0 ≤ x ≤ 1) heat treated at 400 ° C. Specifically, Cl is replaced with Br having a larger ion size. It shows the result of shifting 2θ to the left in XRD.

According to the figure, all samples showed a main peak corresponding to the cubic azirodite phase, and fine impurity peaks for _{LiX and Li 2 S.} As Cl was replaced with Br, the main peak shifted to a lower angle, indicating that the ion size of ^{Br − (1.82 Å for CN=6) is 1.67 Å for Cl −} (coordination number (CN)=6). ), indicating that the lattice is expanded because it is larger than the ion size of .

Optical photographs and SEM photographs of the electrospun PI membrane are shown in FIGS. 5A and 5B, respectively. The SEM picture shows that the PI membrane is composed of randomly arranged nanofibers (diameter: about 500 nm) and contains many void spaces. The measured porosity values were at the level of 80-90%, which was high enough to absorb a sufficient amount of solid electrolyte. As a result of TGA analysis under Ar flow, as shown in FIG. 5c , the thermal decomposition onset temperature was as high as approximately 500°C.

_{The Li 6} PS ₅ Cl _0.5 Br _0.5 -permeated PI membrane (hereinafter, “PI-LPSClBr”) prepared at 400° C. exhibited ductility as shown in FIGS. 5D and 5E . In addition, its surface SEM photograph (Fig. 5f) shows a compacted state containing no detectable cracks. These characteristics are due to the resilience of PI NWs and the deformability of _{Li 6} PS ₅ Cl _0.5 Br _{0.5 .} Due to the excellent mechanical properties of the membrane thus prepared, it can be seen that it is suitable for production on a commercial scale, such as a roll-to-roll process used for commercial LIB production.

The lithium ion conductivity (30°C) and conductivity (30°C) of the solid electrolyte membrane according to the thickness are shown in FIG. 5G and Table 1 below.

A Nyquist plot for the solid electrolyte membrane is shown in FIG. 6 , respectively. _{In addition, the results were compared with the results of the Li 6} PS ₅ Cl _0.5 Br _0.5 -permeated PEI membrane (hereinafter, “PEI-LPSClBr”), which was heat treated at 180°C.

According to Figure 7, PEI-LPSCl showed flexibility. PI-LPSClBr exhibited lithium ion conductivity (30° C.) from 0.058 mS/cm to 0.20 mS/cm (refer to the triangle mark in FIG. 5g). This high conductivity of lithium ions is because PI maintains an undamaged state even at a high temperature heat treatment temperature of 400° C. (a temperature at which Li ₆ PS ₅ Cl _0.5 Br _0.5 can exhibit a conductivity of 2.0 mS/cm) (Fig. 4a). Reference). On the other hand, PEI-LPSClBr heat-treated at 180° C. exhibited a significantly lower lithium ion conductivity (0.0013 mS/cm, indicated by a square in FIG. 5G ). In this regard, it is worth noting that lithium ion conductivity is an important factor compared to lithium ion conductivity in the electrochemical performance of an all-solid-state battery.

The thin (40-70 μm) PI-LPSClBr has similar values (15-29 mS) to the ionic conductivity (29 mS, indicated by diamonds in Fig. 5g _{) of conventional 700 μm-thick Li 6} PS ₅ Cl _0.5 Br _{0.5 pellets.} indicated. This suggests that the use of PI-LPSClBr does not offset the electrochemical performance of all-solid-state lithium secondary batteries (ASLBs). Moreover, the low mass loading of PI-LPSClBr (5.0-9.5 mg/cm 2 vs. about 110 mg/cm 2 in conventional thick-film solid electrolyte pellets) is important for the battery-based energy density of all-solid-state lithium secondary batteries. suggest an advantage.

The electronic conductivity of PI-LPSClBr was also measured by DC polarization using a Ti/PI-LPSClBr/Ti symmetrical cell. PI-LPSClBr ^{exhibited an electron conductivity of about 10 -9} S/cm (see FIG. 8). This value is five orders of magnitude lower than the ionic conductivity (lithium ion transport number: about 0.99999). Figure 5h shows a cross-sectional SEM photograph of PI-LPSClBr and a corresponding EDXS element map (S and Cl). Li ₆ PS ₅ Cl _0.5 Br _0.5 was uniformly present throughout the inner part of the membrane, which effectively penetrated the liquefied solid electrolyte into the porous PI NW during the impregnation process, and Li ₆ PS ₅ Cl _0.5 Br during the low-temperature compression process _Because of the good mechanical sintering of 0.5.

For the electrochemical characterization, an NCM/Li4Ti5O12 (LTO) all-solid-state cell using a 40 μm-thick Li ₆ PS ₅ Cl _0.5 Br _{0.5 -penetrated PI or PEI membrane was fabricated.} Sheet-type NCM and LTO electrodes prepared by the slurry process were used. 9a is a cross-sectional SEM photograph of a NCM/PI-Li ₆ PS ₅ Cl _0.5 Br _0.5 /LTO all-solid-state whole cell and a corresponding element map. It was confirmed that it was in a good contact state.

9b and 9c, the first cycle charge-discharge voltage profile (30° C.) and the corresponding rate rate at 0.22 mA/cm 2 (about 0.1 C) of the NCM/LTO all-solid-state battery using PI-LPSClBr and PEI-LPSClBr The rate capability was compared. The all-solid-state battery using PI-LPSClBr exhibited a significantly higher discharge capacity (126 mA hg _NCM ^-1 ) than that of the all-solid-state battery using PEI-LPSClBr (86 mA g _NCM ^{-1 ).} The trend of rate characteristics was also consistent with this. This large difference is because PI-LPSClBr exhibits superior ionic conductivity compared to PEI-LPSClBr.

Meanwhile, an all-solid NCM/Gr full cell using 40 μm-thick PI-LPSClBr was assembled. The first two-cycle charge/discharge voltage profile at 0.22 mA/cm 2 (about 0.1 C) and 30° C. is shown in FIG. 10A . In spite of the lithium ion conductivity of 0.058 mS/cm for 40 μm-thick PI-LPSClBr, the NCM/Gr all- _{solid-state battery exhibited a high reversible capacity of 146 mA hg NCM-} ¹ , which is the conventional thick-film solid electrolyte ( >1.0 mS/cm, indicating a high lithium ion conductivity). These results indicate that ionic conductivity is more important than ionic conductivity in testing and evaluating the electrochemical performance of all-solid-state batteries. The energy density of the NCM/PI-LPSClBr/Gr all-solid-state battery is 110 Wh kg _cell ^{-1 based on the weight of the cathode, anode, solid electrolyte membrane and current collector (156 Wh kg -1} excluding the weight of the current collector) ). This value is significantly higher than that in the case of using a conventional thick film solid electrolyte. The NCM/PI-LPSClBr/Gr all-solid-state battery exhibited stable cycling performance, and as shown in FIG. 10b , retained 86% of its initial capacity even after 100 cycles.

In addition, the NCM/PI-LPSClBr/Gr all-solid-state battery was exposed to a high temperature condition of 180° C. for 1 hour. Under these harsh conditions, the conventional polymer electrolyte was melted, and the all-solid-state battery could not exhibit an appropriate function and had a problem with regard to safety. For comparison, PEO-Li bis(trifluoromethanesulfonyl)imide (LiTFSI) containing 10% by weight of alumina nanoparticles as a model for a conventional polyelectrolyte or OPC solid electrolyte was prepared. The PEO-LiTFSI-Al ₂ O ₃ film exhibited significant thermal shrinkage when exposed to a temperature of 180° C. and completely lost its initial morphology when exposed to a temperature of 400° C. (see FIG. 11 ). On the other hand, the charge/discharge voltage profile of the NCM/PI-LPSClBr/Gr all-solid-state battery after exposure to a temperature of 180° C. still almost overlapped with the value before exposure ( FIG. 10c ), supporting excellent thermal stability and safety. do.

The electrochemical performance of the NCM/PI-LPSClBr/Gr all-solid-state battery in terms of membrane thickness and areal capacity was compared with that of a conventional free-standing solid electrolyte membrane (see FIG. 10d ). An all-solid-state battery using a polymer electrolyte or OPC solid electrolyte membrane was tested at a high temperature (55-80°C). The thickness of PI-LPSClBr (40 μm) was the lowest. Moreover, the all-solid-state battery using PI-LPSClBr outperformed the case in which conventional polymer electrolytes or OPC solid electrolyte membranes are used, despite similar lithium ion conductivity. This fact can be attributed to the single ion conductivity.

In this example, an all-solid-state battery was prepared by permeating the solid electrolyte solution into the pre-assembled cathode/polymer NW membrane/anode. _{Conventional LiCoO 2} (LCO) and LTO electrodes (used in conventional LIBs) prepared using a slurry were used. Liquefied Li ₆ PS ₅ Cl _0.5 Br _0.5 penetrated into the porous structure of the LCO/PI/LTO assembly. After solvent removal and subsequent heat treatment, cold pressing is performed to make Li ₆ PS ₅ Cl _0.5 Br _0.5 crystals densely fill the pores, thereby forming an effective lithium ion conduction path throughout the entire cell. Due to the limited thermal stability of the PVDF binder in the electrode, the heat treatment temperature was set at 180°C. The first cycle charge-discharge voltage profile (0.1 C and 70° C.) for the Li ₆ PS ₅ Cl _0.5 Br _0.5 -permeated LCO/PI/LTO all-solid-state battery is shown in FIG. 10E , and the initial discharge capacity was 101 mA hg _LCO ^-1 .

Effect of solvent in the preparation of solid electrolyte solution

_{When a sulfide-based solid electrolyte (Li 6} PS ₅ Cl) was dissolved in two solvents (ethanol and xylene) using dynamic light scattering (DLS) equipment, the particle size in the solution (concentration: 5 wt%) was analyzed. , the results are shown in FIG. 12 .

According to the figure, as the sulfide-based solid electrolyte showed high solubility in ethanol, the particle size was measured to be 0 (measureable to about 0.1 nm according to the equipment specification). As such, when ethanol was used as a solvent for preparing a solid electrolyte solution, a uniform solution having a particle size of the solid electrolyte of 0.1 nm or less could be prepared. On the other hand, when xylene, which is a non-polar solvent, was used, the sulfide-based solid electrolyte was not dissolved and was dispersed in a size of about 2 to 4 μm. Considering that the polyimide (PI) nonwoven fabric has a pore size of 1 μm or less, when xylene is used as a solvent, it indicates that it is not suitable for use as an impregnation solution.

_{In addition, when Li 6} PS ₅ Cl as a sulfide-based solid electrolyte and ethanol as its solvent are used, Raman spectroscopy analysis was performed _{on Li 6} PS ₅ Cl dissolved in ethanol to determine whether a side reaction occurs, The results are shown in FIG. 13 . Referring to the drawings, ethanol and PS ₄ ^3- were confirmed in the solid electrolyte solution. The main unit constituting _{Li 6} PS _{5 Cl was PS 4} ^3- bar, and when it was dissolved in ethanol, _{PS 4} ^3- of PS ₅ Cl was clearly observed. Therefore, it was confirmed that the solid electrolyte was effectively dissolved in ethanol without a side reaction.

It was evaluated whether the sulfide-based solid electrolyte (Li ₆ PS ₅ Cl) maintains its initial properties before and after impregnation in the porous polymer support (heat treatment or heating is performed), and the results are shown in FIG. 14 . According to the figure, no special change was observed even after the solution process. Therefore, as a _{result of Raman spectroscopy analysis of Li 6} PS ₅ Cl before and after the solution process, it was confirmed that _{Li 6} PS ₅ Cl was maintained even before and after the solution process.

While penetrating the sulfide-based solid electrolyte solution into the porous polymer support, it was evaluated whether the positive electrode active material (LCO) of the cathode causes denaturation of the positive electrode active material when contacted, and the results are shown in FIG. 15 . _{According to the figure, a similar Raman peak was exhibited even when LiCoO 2} , which is a cathode active material, _{was in contact with or exposed to a Li 6} PS ₅ Cl-ethanol solution during the impregnation process, suggesting that the original crystal structure was maintained without side reactions.

Simple modifications or changes of the present invention can be easily used by those of ordinary skill in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (19)

preparing a solid electrolyte solution by dissolving a sulfide-based solid electrolyte capable of a solution process in a solvent;
Separately, forming a pre-laminate or assembly comprising a cathode, a porous polymer support and an anode;
impregnating the laminate with a solid electrolyte solution to fill the pores of the porous polymer support with a solid electrolyte; and
heat-treating the laminate filled with the solid electrolyte;
includes,
wherein the porous polymer support has a porosity of at least 60% and a thickness of 5 to 150 μm, and
The heat treatment step is performed at at least 200 ℃ method of manufacturing an all-solid-state lithium secondary battery to form a solid electrolyte having increased crystallinity. According to claim 1, wherein the porous polymer support is polyimide, polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyamide, polytetrafluoroethylene (PTFE), polysulfone (PSF), poly A method of manufacturing an all-solid-state lithium secondary battery, characterized in that at least one material selected from the group consisting of ether ketone (PEK) and polyether ether ketone (PEEK). The method of claim 2, wherein the porous polymer support is made of a polyimide material represented by the following formula (1):
[Formula 1]

In the above formula, n is a polymerization degree of 500 to 10000. The method of claim 1, wherein the melting point of the porous polymer support is at least 200°C. The method of claim 1, wherein the average pore size of the porous polymer support is in the range of 0.01 to 10 μm. The method according to claim 1, wherein the porous polymer support is in the form of a nonwoven fabric or a web, and the diameter of individual fibers constituting it is in the range of 100 to 1000 nm. The method of claim 1, wherein the porous polymer support has a conductivity of 10 ^-8 S/cm or less. The method according to claim 3, wherein the porous support made of polyimide is manufactured by an electrospinning method,
At this time, the method of manufacturing an all-solid-state lithium secondary battery, characterized in that the applied voltage is controlled within the range of 5 to 30 kV, and the distance between the collector and the spinneret is in the range of .10 to 30 cm. The method of claim 3, wherein the imidization rate of the polyimide is at least 80%. The method according to claim 1, wherein the sulfide-based solid electrolyte is represented by the following general formula (1):
[General formula 1]
Li _6-m PS _5-m X _1+m
In the above formula, X is at least one halogen element selected from the group consisting of Cl, Br and I,
m is 0 to 1. 11. The method of claim 10, wherein the sulfide-based solid electrolyte is represented by the following general formula (2):
[General Formula 2]
Li ₆ PS ₅ Cl _1-x Br _x (0<x<1). The method of claim 1, wherein the sulfide-based solid electrolyte has a lithium argyrodite crystal structure. The method of claim 1 , wherein the lithium ion conductivity (30° C.) of the sulfide-based solid electrolyte is at least 0.5 mS/cm. The method of claim 1, wherein the solvent in the solid electrolyte solution is an alcohol or an amine solvent. At least one selected from the group consisting of a ketone-based solvent and an ether-based solvent, wherein the concentration of the solid electrolyte in the solid electrolyte solution is 0.1 to 1 M. A method of manufacturing an all-solid lithium secondary battery. The all-solid-state lithium secondary battery according to claim 1, wherein, in the step of impregnating the solid electrolyte solution, the solid electrolyte solution is impregnated into at least one of the cathode and the anode as well as the pores of the porous polymer support in the laminate. manufacturing method. An all-solid-state lithium secondary battery comprising a laminate in which a cathode, a solid electrolyte layer, and an anode are stacked,
The solid electrolyte layer includes (i) a porous polymer support and (ii) a sulfide-based solid electrolyte filled in pores of the porous polymer support,
wherein the porous polymer support has a porosity of at least 60% and a thickness of 5 to 150 μm, and
The all-solid-state lithium secondary battery, wherein the crystallinity of the filled sulfide-based solid electrolyte is at least 60%. The method of claim 16, wherein the content of the sulfide-based solid electrolyte in the solid electrolyte layer is in the range of 60 to 95% by weight, and
An all-solid-state lithium secondary battery, characterized in that the mass per area of the solid electrolyte layer is in the range of 2 to 15 mg/cm 2 . The all-solid-state lithium secondary battery according to claim 16, wherein the conductivity (30° C.) of the solid electrolyte layer is in the range of at least 0.001 mS/cm. The method of claim 16, wherein the positive electrode active material is attached to said cathode has _{LiCoO 2 (LCO), LiNi 2} O 2, LiNi 0 .85 Co 0 .10 Al 0 .05 O 2 (NCA), LiNi 0 .33 Co 0. and _{33 Mn 0 .33 O 2 (NMC} ), LiNi 0 .5 Mn 0 .5 O , or a combination thereof, and
The negative active material attached to the anode is a carbonaceous material, or LTO (Li ₄ Ti ₅ O ₁₂ ), TiO ₂ , SiO _x , SnO _x , CuO _x , VO _x , In ₂ O ₃ Or an all-solid-state lithium secondary battery, characterized in that the lithium composite oxide is a combination thereof.

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