Electrode comprising mixed ionic-electronic conductor (MIEC) for lithium secondary battery, and production method therefor

Abstract

The present invention relates to an electrode comprising a mixed ionic-electronic conductor for a lithium secondary battery, and a production method therefor, and more specifically to an electrode comprising a mixed ionic-electronic conductor, and a production method, the electrode having both excellent ionic conductivity and electronic conductivity by complexing a mixed ionic-electronic conductor and an electrode material for a lithium secondary battery. According to the present invention, the ionic conductivity and electronic conductivity of the electrode may be simultaneously enhanced. In addition, according to the present invention, when fast charging / discharging, performance degradation may be prevented, and the capacity retention rate may be improved. In addition, according to the present invention, the electrochemical stability of the battery may be enhanced by reducing the interfacial resistance between the electrode and a solid electrolyte.

Description

Electrode comprising a mixed ion-electron conductor (MIEC) for a lithium secondary battery and method for manufacturing the same

[0001] The present invention relates to an electrode comprising a mixed ion-electron conductor for a lithium secondary battery and a method for manufacturing the same. More specifically, it relates to an electrode comprising a mixed ion-electron conductor having excellent ion conductivity and electron conductivity through the composite formation of an electrode material for a lithium secondary battery and a mixed ion-electron conductor, and a method for manufacturing the same.

[0002] This research was supported by the Ministry of Trade, Industry and Energy and the Korea Institute of Industrial Technology Planning and Evaluation (KEIT) in 2023 (RS-2023-00243593).

[0003] In addition, this research was conducted with funding from the Ministry of Trade, Industry and Energy and the Korea Institute for Industrial Technology Advancement (KIAT) in 2024 and supported by KIAT (RS-2024-00436216).

[0004]

[0005] Lithium-ion batteries are used as essential energy storage devices in various applications, such as electric vehicles, energy storage systems, and portable electronic devices, due to their high energy density and long cycle life. However, the performance of conventional lithium-ion batteries is limited by the electrochemical properties and structural stability of electrode materials, and in particular, the ionic and electronic conductivity characteristics of the electrodes have a significant impact on battery performance.

[0006] Currently, commercial lithium-ion batteries consist of a combination of carbon-based materials with excellent electronic conductivity and liquid electrolytes with ion conductivity. However, this structure leads to safety issues, such as restricted lithium ion migration pathways, leakage of the liquid electrolyte, and fire hazards. To address these issues, solid-electrolyte-based lithium-ion batteries are garnering attention, and effective bonding technology between the solid electrolyte and electrode materials is particularly necessary.

[0007] Mixed ion-electron conductors (MIECs) are materials capable of simultaneously conducting lithium ions and electrons, and are attracting attention as electrode materials for next-generation lithium secondary batteries. When MIECs are combined with electrode materials, the movement pathways of lithium ions and electrons are improved, increasing the utilization rate of the active material and enhancing the energy density and output performance of the battery.

[0008] Based on this background, the present invention proposes a technology that effectively combines MIEC with an electrode material to maximize the ion and electron conductivity of the electrode and thereby improve the performance of a lithium secondary battery. The manufacturing method of the present invention aims to increase the electrochemical reaction surface area and improve the conductivity of the entire electrode by fixing MIEC to the surface and internal pores of the electrode material.

[0009]

[0010] The present invention has been devised to solve the aforementioned problems, and the objective of the present invention is to provide an electrode comprising a mixed ion electronic conductor in which an electrode material and a mixed ion electronic conductor are combined.

[0011] In addition, a method for manufacturing an electrode comprising a mixed ion electron conductor that fixes the mixed ion electron conductor in the surface and internal pores of the electrode material is provided.

[0012] The technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the present invention belongs from the description below.

[0013]

[0014] As a technical means for achieving the aforementioned technical problem, one aspect of the present invention is,

[0015] The present invention provides a method for manufacturing an electrode comprising a mixed ion electron conductor, comprising the steps of: preparing a mixed ion electron conductor (MIEC) and an electrode material, respectively; and combining the mixed ion electron conductor (MIEC) and the electrode material; wherein, after the step of combining the mixed ion electron conductor (MIEC) and the electrode material, the mixed ion electron conductor (MIEC) is fixed to the surface and internal pores of the electrode material to form a transmission path for electrons or ions.

[0016] The step of compounding the above-mentioned mixed ion electron conductor and electrode material may include the step of mixing the mixed ion electron conductor and electrode material by ball milling; and the step of sintering the mixture.

[0017] The step of mixing the above-mentioned mixed ion electronic conductor and electrode material by ball milling can be performed for 6 to 24 hours at a speed of 100 to 1000 rpm.

[0018] The step of sintering the above mixture can be performed at a temperature of 900 to 1500 ℃ for 6 to 30 hours.

[0019] The step of compounding the above-mentioned mixed ion electronic conductor and electrode material may include: a step of preparing the mixed ion electronic conductor as a sputtering target; and a step of depositing the mixed ion electronic conductor through plasma discharge.

[0020] The step of compounding the mixed ion electron conductor and the electrode material may include: a step of preparing a dispersion by dispersing the mixed ion electron conductor in a solvent; a step of immersing the electrode material in the dispersion; a step of drying the electrode material immersed in the dispersion; and a step of heat-treating the electrode material at a temperature of 200 to 500 ℃.

[0021] The step of compounding the mixed ion electron conductor and the electrode material may include: a step of preparing a dispersion by dispersing the mixed ion electron conductor in a solvent; a step of immersing the electrode material in the dispersion; a step of applying a voltage of 20 to 50 V to the electrode material immersed in the dispersion; and a step of heat-treating the electrode material at a temperature of 200 to 500 ℃.

[0022] The above mixed ionic electronic conductor is metal-doped LLZO(Li7La3Zr2O 12 ), LLZO, metal-doped LATP (Li 1+x Al x Ti 2-x (PO4)3) (0≤x≤0.5), LATP, metal-doped LLTO(Li 3y La 2 / 3-y TiO3) (0 <y≤0.16), LLTO, LLMnO (Li 0.34 La 0.55 MnO 3-z ) (0≤z≤1), Li a La b MeO3(Me = Ti, Cr, Mn, Fe, Co) (0 <a<2, 0<b<3), La 1-x Sr x MnO3(LSM) (0≤x≤0.5), SrCoO3, BaCoO3, La 0.6 Sr 0.4 It can be characterized by being composed of CoO3, TiO2, Li3Si, NiO, ZnO, and combinations thereof.

[0023] In one embodiment of the present invention, the doped metal may be Y, Ce, Ta, Al, Mg, Ti, Fe, Zn, Ga, Br, B, Mn, Sc, Nb, W, Zr, Cr, Cu, Ge, Sn, Sr, or a combination thereof.

[0024]

[0025] Another aspect of the present invention is,

[0026] It comprises an electrode material layer; and a mixed ion electron conductor (MIEC) contained in the surface and internal pores of the electrode material layer, wherein the mixed ion electron conductor is a metal-doped LLZO (Li7La3Zr2O 12 ), LLZO, metal-doped LATP (Li 1+x Al x Ti 2-x (PO4)3) (0≤x≤0.5), LATP, metal-doped LLTO(Li 3y La 2 / 3-y TiO3) (0 <y≤0.16), LLTO, 및 이들의 조합으로 이루어진 것을 특징으로 하는, 혼합 이온 전자 전도체를 포함하는 전극을 제공한다.

[0027] The doped metal may be Y, Ce, Ta, Al, Mg, Ti, Fe, Zn, Ga, Br, B, Mn, Sc, Nb, W, Zr, Cr, Cu, Ge, Sn, Sr, or a combination thereof.

[0028] The surface of the electrode material layer further includes a coating layer having a thickness of 100 nm to 10 μm, and the coating layer may be made of a mixed ion electron conductor.

[0029] The above mixed ionic electronic conductor is 1.0 x 10 -8 Up to 1.0 x 10 -4 It can have an electron conductivity of S / cm.

[0030] The above mixed ionic electronic conductor is 1.0 x 10 -6 Up to 1.0 x 10 -3 It can have an ionic conductivity of S / cm.

[0031]

[0032] According to the present invention, the ionic conductivity and electronic conductivity of the electrode can be improved simultaneously.

[0033] In addition, according to the present invention, performance degradation during high-speed charging / discharging can be prevented and the capacity retention rate can be improved.

[0034] In addition, according to the present invention, the electrochemical stability of the battery can be improved by reducing the interfacial resistance between the electrode and the solid electrolyte.

[0035] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the composition of the invention described in the description or claims of the present invention.

[0036]

[0037] Figure 1 is the SEM result of Example 1 and Comparative Example 1 according to one embodiment of the present invention.

[0038] Figure 2 is an SEM result of Example 1 according to one embodiment of the present invention.

[0039] Figure 3 shows the Galvanostatic Cycling results of Example 1 and Comparative Example 1 according to one embodiment of the present invention.

[0040]

[0041] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0042]

[0043] Example 1: Electrode comprising a mixed ion electron conductor (MIEC)

[0044] In Example 1, an electrode containing a mixed ion electron conductor was prepared using a sintering method.

[0045] First, ZnO as a mixed ionic electronic conductor x Si / SiO as a electrode plate material x and LLZO (Li7La3Zr2O 12Powder was prepared. To mix each material, it was fed into a high-speed ball mill (Planetary Ball Mill). At this time, the powder containing the mixed ion electron conductor and electrode material and the balls were fed in a ratio of 1:6. Mixing in the high-speed ball mill was carried out at a speed of 300 rpm for 6 to 24 hours to obtain a homogeneous mixture.

[0046] Afterward, the mixed powder was placed in an alumina crucible and sintered at 900 to 1200 °C for 6 to 30 hours. The sintering rate was set to 5 °C / min, and the cooling rate after sintering was controlled to 3 °C / min. Through this process, an electrode containing a mixed ionic electron conductor was manufactured.

[0047]

[0048] Example 2: Electrode comprising a mixed ion electron conductor (MIEC)

[0049] In Example 2, an electrode containing a mixed ion electron conductor was prepared using PVD (physical vapor deposition).

[0050] First, a mixed ion electron conductor was set as the sputtering target material, and the surface of the electrode material was cleaned to remove contaminants. Afterwards, the inside of the chamber of the sputtering device was cleaned to remove impurities, and the inside of the chamber was brought to a vacuum state (10 -5 ~10 -6 It is maintained at (Torr). Argon (Ar) gas was used as the sputtering gas, and the sputtering gas was supplied until the pressure inside the chamber reached 5 to 10 mTorr.

[0051] Afterwards, MIEC particles were uniformly coated on the surface of the electrode material through plasma discharge and introduced into the internal pores of the electrode material. Through this process, an electrode containing a mixed ion electron conductor was manufactured.

[0052]

[0053] Example 3: Electrode comprising a mixed ion electron conductor (MIEC)

[0054] In Example 3, an electrode containing a mixed ion electron conductor was prepared using dip coating.

[0055] First, a dispersion is prepared by sonicating a mixed ionic electron conductor in ethanol, isopropanol, or NMP solvent. After immersing the electrode material in the prepared dispersion, and after a certain period of time, the electrode material is slowly withdrawn at a speed of 1 to 5 mm / s.

[0056] The electrode material immersed in the dispersion was dried at a temperature of 80 to 120 ℃ and then heat-treated at a temperature of 200 to 500 ℃ to uniformly coat the surface of the electrode material with MIEC particles and introduce them into the internal pores of the electrode material. Through this process, an electrode containing a mixed ionic electron conductor was manufactured.

[0057]

[0058] Example 4: Electrode comprising a mixed ion electron conductor (MIEC)

[0059] In Example 4, an electrode containing a mixed ion electron conductor was prepared using electrophoretic deposition (EPD).

[0060] First, a dispersion is prepared by sonicating a mixed ionic electron conductor in a mixed solution of isopropanol and acetone. After immersing an electrode material in the prepared dispersion, a DC voltage (20 to 50 V) is applied to deposit MIEC particles on the surface or in the internal pores of the electrode material. Subsequently, heat treatment is performed at a temperature of 200 to 500 ℃ to uniformly coat the MIEC particles on the surface of the electrode material and introduce them into the internal pores of the electrode material. Through this process, an electrode containing a mixed ionic electron conductor is manufactured.

[0061]

[0062] Comparative Example 1: Electrode

[0063] The silicon electrode material used in Example 1 was designated as Comparative Example 1.

[0064]

[0065] Experimental Example 1: SEM (Scanning Electron Microscope)

[0066] To confirm the particles of Example 1 and Comparative Example 1, they were observed using a scanning electron microscope (SEM), and the results are shown in Figures 1 and 2.

[0067] First, FIG. 1 compares the particles of the electrode material with and without MIEC, where FIG. 1(a) is the result of Comparative Example 1 and FIG. 1(b) is the result of Example 1.

[0068] First, looking at Fig. 1(a), it can be seen that voids exist inside the electrode material and empty spaces are formed. On the other hand, looking at Fig. 1(b), it can be seen that after sintering, MIEC uniformly coats the surface of the electrode material and fills the internal voids between the electrode material.

[0069] Figure 2 is the result of Example 1. Looking at Figure 2, it can be seen that a coating layer is formed on the surface of the electrode material. It can also be seen that the internal voids of the electrode material are filled with MIEC.

[0070] In this way, as MIEC fills the internal voids of the electrode layer, it can be expected that the electrical resistance within the electrode will decrease and the reactivity will be improved.

[0071]

[0072] Experimental Example 2: Measurement of Electronic Conductivity and Ionic Conductivity

[0073] The ionic conductivity and electronic conductivity of Example 1 and Comparative Example 1 were measured and are shown in Table 1 below.

[0074]

[0075] Comparative Example 1 Example 1 Ion conductivity 10 -6 ~10-5 S / cm10 -5 ~10 -4 S / cm electron conductivity-10 -7 ~10 -6 S / cm

[0076]

[0077] The ionic conductivity of Example 1 is 10 -5 ~10 -4 Comparative example in S / cm (10 -6 ~10 -5 It can be confirmed that the ionic conductivity has improved compared to S / cm. In addition, the electronic conductivity of Example 1 is also 10 -7 ~10 -6 It was measured in S / cm, and it can be confirmed that it is improved compared to Comparative Example 1 (which was not measured because the value was too low).

[0078] Through this, it was confirmed that in the case of the embodiment of the present invention incorporating MIEC, both electronic conductivity and ionic conductivity were improved.

[0079]

[0080] Experimental Example 3: Galvanostatic Cycling Measurement

[0081] The voltage behavior according to the change in current steps under the Galvanostatic Cycling conditions of Example 1 and Comparative Example 1 was confirmed and is shown in FIG. 3. FIG. 3(a) is the result of Comparative Example 1, and FIG. 3(b) is the result of Example 1.

[0082] First, looking at Fig. 3(a), the current density is 0.65 mA / cm² 2 When it reached, a short circuit occurred. This is because the ionic conductivity of Comparative Example 1 is approximately 10 -6 ~10 -5 It is interpreted as a result of reduced electrochemical stability, as the low S / cm and poor electronic conductivity at an unmeasurable level.

[0083] In contrast, looking at Fig. 3(b), the current density is 2.0 mA / cm² 2It can be confirmed that the voltage remains stable even when increased to [amount]. This is because in Example 1 of the present invention, the ionic conductivity is approximately 10 -5 ~10 -⁴ It is improved to S / cm, and the electron conductivity is also 10 -7 ~ 10 -6 It is interpreted as an improved result in S / cm.

[0084] Accordingly, according to an embodiment of the present invention, ionic conductivity and electronic conductivity were simultaneously improved by introducing a mixed ion-electron conductor (MIEC), and as a result, electrochemical stability was significantly enhanced even under conditions where current density increased. These results indicate that the embodiment of the present invention improves charge transfer characteristics at the electrode-electrolyte interface, thereby enabling stable electrochemical behavior even at high current densities.

[0085]

[0086] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0087] The scope of the present invention is defined by the claims set forth below, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention.

[0088]

[0089] The present invention will be described in more detail below. However, the present invention may be implemented in various different forms and is not limited by the embodiments described herein, and is defined only by the claims set forth below.

[0090] Additionally, the terms used in this invention are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. Throughout the specification of this invention, the term 'comprising' any component means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0091] Throughout the specification, when it is stated that a part is "connected (connected, in contact, combined)" with another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly connected" with other members interposed between them. Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but rather allows for the inclusion of additional components.

[0092] The terms used in this specification are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise.

[0093]

[0094] The first aspect of the present invention is,

[0095] The present invention provides a method for manufacturing an electrode comprising a mixed ion electron conductor, comprising the steps of: preparing a mixed ion electron conductor (MIEC) and an electrode material, respectively; and combining the mixed ion electron conductor (MIEC) and the electrode material; wherein, after the step of combining the mixed ion electron conductor (MIEC) and the electrode material, the mixed ion electron conductor (MIEC) is fixed to the surface and internal pores of the electrode material to form a transmission path for electrons or ions.

[0096]

[0097] Hereinafter, a method for manufacturing an electrode comprising a mixed ion electron conductor according to the first aspect of the present invention will be described in detail.

[0098]

[0099] In one embodiment of the present invention, the mixed ion-electron conductor may be a material having both ion conductivity and electron conductivity.

[0100] In one embodiment of the present invention, the electrode material may be a positive electrode material and / or a negative electrode material, and may be a composite of a positive electrode material and a solid electrolyte and / or a composite of a negative electrode material and a solid electrolyte.

[0101] In one embodiment of the present invention, the method comprises the step of compounding the mixed ion electron conductor (MIEC) and the electrode material; subsequently, the mixed ion electron conductor (MIEC) may be fixed to the surface and internal pores of the electrode material. The mixed ion electron conductor may be incorporated into the surface and internal pores of the electrode material and act as a conductive material. By filling the internal pores of the electrode material with the mixed ion electron conductor, the electrical resistance within the electrode can be reduced and reactivity increased.

[0102] In one embodiment of the present invention, the step of compounding the mixed ion electron conductor and the electrode material may include: a step of mixing the mixed ion electron conductor and the electrode material by ball milling; and a step of sintering the mixture.

[0103] In one embodiment of the present invention, the step of mixing the mixed ion electron conductor and the electrode material by ball milling may be a step of mechanically mixing the mixed ion electron conductor and the electrode material. The ball milling step may uniformly disperse the MIEC so that the MIEC adheres evenly to the surface of the electrode material.

[0104] In one embodiment of the present invention, the step of mixing the mixed ion electronic conductor and the electrode material by ball milling may be performed for 6 to 24 hours at a speed of 100 to 1000 rpm. In another example of the present invention, the step of mixing the mixed ion electronic conductor and the electrode material by ball milling may preferably be performed for 6 to 20 hours. More preferably, it may be performed for 8 to 20 hours. If the mixing step by milling is below the above range, the mixed ion electronic conductor and the electrode material may not be sufficiently mixed, and the MIEC may not be contained in the surface and internal pores of the electrode material. If the mixing step by milling is above the above range, aggregation between the mixed ion electronic conductor and the electrode material may occur.

[0105] In another example of the present invention, the step of mixing the mixed ion electronic conductor and the electrode material by ball milling can preferably be mixed at a speed of 100 to 800 rpm, and more preferably at a speed of 200 to 700 rpm. If the speed of the mixing step by milling is below the above range, the mixed ion electronic conductor and the electrode material are not sufficiently mixed, and the MIEC may not be contained in the surface and internal pores of the electrode material. If the speed of the mixing step by milling is above the above range, aggregation between the mixed ion electronic conductor and the electrode material may occur.

[0106] In one embodiment of the present invention, in the step of mixing the mixed ion electronic conductor and the electrode material by ball milling, the ratio of the powder containing the mixed ion electronic conductor and the electrode material to the balls may be 1:1 to 1:10. In another example of the present invention, the ratio of the powder containing the mixed ion electronic conductor and the electrode material to the balls may preferably be 1:1 to 1:8, and more preferably 1:2 to 1:8. If the ratio of the powder containing the mixed ion electronic conductor and the electrode material to the balls falls outside the above range, sufficient mixing of the powder does not occur, and the MIEC may not be contained in the surface and internal pores of the electrode material. Additionally, if it falls outside the above range, unnecessary aggregation between the mixed ion electronic conductor and the electrode material may occur.

[0107] In one embodiment of the present invention, the step of mixing the mixed ion electron conductor and the electrode material by ball milling may involve introducing a precursor of the mixed ion electron conductor instead of introducing the mixed ion electron conductor.

[0108] In one embodiment of the present invention, the step of sintering the mixture may be performed at a temperature of 400 to 1500 °C for 6 to 30 hours. In another example of the present invention, the step of sintering the mixture may preferably be performed at a temperature of 500 to 1300 °C, and more preferably at a temperature of 500 to 1200 °C. If the temperature of the step of sintering the mixture is below the above range, sufficient heat treatment is not provided, and the MIEC may not be included in the surface and internal pores of the electrode material. If the temperature of the step of sintering the mixture is above the above range, the MIEC may be sintered or impurities may be generated.

[0109] In another example of the present invention, the step of sintering the mixture may preferably be performed for 6 to 25 hours, and more preferably for 10 to 25 hours. If the time of the step of sintering the mixture is less than the above range, sufficient heat treatment is not involved, and the MIEC may not be included in the surface and internal pores of the electrode material. If the time of the step of sintering the mixture is greater than the above range, the MIEC may be sintered or impurities may be generated.

[0110] In one embodiment of the present invention, the step of sintering the mixture may be performed after adding an excess amount of lithium to the mixture. Since the step of sintering the mixture is performed at a high temperature, lithium may evaporate, and if lithium evaporates, the performance of the electrode may deteriorate. To prevent this, an excess amount of lithium may be added to the surface of the mixture.

[0111] In one embodiment of the present invention, the step of sintering the mixture can be performed by covering the crucible with a lid. If the crucible is not covered, lithium may evaporate and the performance of the electrode may be degraded.

[0112] In one embodiment of the present invention, the step of sintering the mixture may further include the addition of a sintering aid. The sintering aid is not limited to any specific type as long as it is a material capable of assisting in the sintering of the composite of the mixed ion electron conductor and the electrode material.

[0113] In one embodiment of the present invention, the step of sintering the mixture may be heated at a rate of 3 to 10 ℃ / min. Preferably, the heating may be heated at a rate of 5 ℃ / min. In one embodiment of the present invention, the step of sintering the mixture may be cooled at a rate of 2 to 5 ℃ / min after sintering is completed. Preferably, the cooling may be performed at a rate of 3 ℃ / min.

[0114] In one embodiment of the present invention, the step of compounding the mixed ion electron conductor and the electrode material may include: the step of preparing the mixed ion electron conductor as a sputtering target; and the step of depositing the mixed ion electron conductor through plasma discharge.

[0115] In one embodiment of the present invention, the method may further include the step of preparing the mixed ion electron conductor as a sputtering target; and the step of cleaning the electrode material prior to that. The step of cleaning the electrode material may remove contaminants by polishing the surface of the electrode material. The step of cleaning the electrode material may remove surface contaminants by ultrasonic cleaning.

[0116] In one embodiment of the present invention, the method may further include the step of preparing a mixed ion electron conductor as a sputtering target; and subsequently, the step of lowering the pressure inside the sputtering device. In one embodiment of the present invention, the interior of the sputtering device may be in a vacuum state. Preferably, the interior of the sputtering device is 10 -2 to 10 -7 It could be Torr.

[0117] In one embodiment of the present invention, the step of preparing a mixed ion electronic conductor as a sputtering target may involve mounting the mixed ion electronic conductor as a sputtering target material in a sputtering device. In another example of the present invention, the step of preparing a mixed ion electronic conductor as a sputtering target may involve introducing a precursor of the mixed ion electronic conductor as a sputtering target material. That is, the mixed ion electronic conductor may be added according to the process conditions of the sputtering step.

[0118] In one embodiment of the present invention, the method may further include the step of preparing a mixed ion electron conductor as a sputtering target; and subsequently, the step of supplying a sputtering gas into a sputtering chamber. The sputtering gas may be argon (Ar) or a mixed gas of argon / oxygen (Ar / O2). In another example of the present invention, when the mixed ion electron conductor is an oxide, the sputtering gas may be a mixed gas of argon and oxygen, and the ratio may be 9:1 or 8:2.

[0119] In one embodiment of the present invention, the step of supplying the sputtering gas into the sputtering chamber may supply the sputtering gas until the pressure inside the sputtering chamber reaches 5 to 10 mTorr. If the pressure falls outside this range, discharge may not occur, and sufficient deposition may not occur.

[0120] In one embodiment of the present invention, the step of depositing a mixed ion electron conductor through the plasma discharge may supply RF (radio frequency) at 50 to 200 W. If the range is exceeded, sufficient plasma discharge may not occur, and the deposition on the electrode material may not be sufficient.

[0121] In one embodiment of the present invention, the step of depositing a mixed ion electron conductor through the plasma discharge may be performed for a time of 10 minutes to 1440 minutes. Preferably, it may be performed for 30 minutes to 720 minutes. The deposition step may help to control the thickness of the coating layer.

[0122] In one embodiment of the present invention, the step of depositing a mixed ion electron conductor through the plasma discharge may be performed while rotating a sample stage. The sample stage may rotate for a uniform coating. The rotation may be performed at a speed of 5 to 10 rpm.

[0123] In one embodiment of the present invention, the mixed ion electron conductor may be included in the surface and internal pores of the electrode material through the plasma discharge.

[0124] In one embodiment of the present invention, the step of compounding the mixed ion electron conductor and the electrode material may include: a step of preparing a dispersion by dispersing the mixed ion electron conductor in a solvent; a step of immersing the electrode material in the dispersion; a step of drying the electrode material immersed in the dispersion; and a step of heat-treating the electrode material at a temperature of 200 to 500 ℃.

[0125] In one embodiment of the present invention, the step of preparing a dispersion by dispersing the mixed ionic electron conductor in a solvent; wherein the solvent may be ethanol, isopropanol, or NMP (N-methyl-2-pryrrolidone).

[0126] In one embodiment of the present invention, the step of preparing a dispersion by dispersing the mixed ion electron conductor in a solvent can be performed by ultrasonic treatment.

[0127] In one embodiment of the present invention, the step of immersing an electrode material in the dispersion solution; thereafter, the electrode material immersed in the dispersion solution can be withdrawn at a speed of 1 to 5 mm / s.

[0128] In one embodiment of the present invention, the step of drying the electrode material immersed in the dispersion may be performed at a temperature of 80 to 120°C. The drying step may be a step of drying the solvent.

[0129] In one embodiment of the present invention, the step of heat-treating the electrode material at a temperature of 200 to 500 ℃ may be a step of fixing MIEC in the surface and internal pores of the electrode material. If the range is exceeded, MIEC may not be included in the surface and internal pores of the electrode material, or impurities may be generated.

[0130] In one embodiment of the present invention, the step of compounding the mixed ion electron conductor and the electrode material may include: a step of preparing a dispersion by dispersing the mixed ion electron conductor in a solvent; a step of immersing the electrode material in the dispersion; a step of applying a voltage of 20 to 50 V to the electrode material immersed in the dispersion; and a step of heat-treating the electrode material at a temperature of 200 to 500 ℃.

[0131] In one embodiment of the present invention, in the step of preparing a dispersion by dispersing the mixed ion electron conductor in a solvent, the solvent may be a mixed solution of isopropanol and acetone.

[0132] In one embodiment of the present invention, the step of preparing a dispersion by dispersing the mixed ion electron conductor in a solvent can be performed by ultrasonic treatment.

[0133] In one embodiment of the present invention, the step of applying a voltage of 20 to 50 V to an electrode material immersed in the dispersion liquid may be a step of fixing MIEC to the surface and internal pores of the electrode material.

[0134] In one embodiment of the present invention, the step of heat-treating the electrode material at a temperature of 200 to 500 ℃ may be a step of stabilizing the MIEC fixed to the surface and internal pores of the electrode material.

[0135] In one embodiment of the present invention, the mixed ion electronic conductor is metal-doped LLZO(Li7La3Zr2O 12 ), LLZO, metal-doped LATP (Li 1+x Al x Ti 2-x (PO4)3) (0≤x≤0.5), LATP, metal-doped LLTO(Li 3y La 2 / 3-y TiO3) (0 <y≤0.16), LLTO, LLMnO (Li 0.34 La 0.55 MnO 3-z ) (0≤z≤1), Li a Lab MeO3(Me = Ti, Cr, Mn, Fe, Co) (0 <a<2, 0<b<3), La 1-x Sr x MnO3(LSM) (0≤x≤0.5), SrCoO3, BaCoO3, La 0.6 Sr 0.4 It may be characterized by being composed of CoO3, TiO2, Li3Si, NiO, ZnO, and combinations thereof. In another example of the present invention, the mixed ionic electron conductor may preferably be metal-doped LLZO, metal-doped LATP, or metal-doped LLTO.

[0136] When LLTO (Lithium Lanthanum Titanium Oxide) is used as a mixed-ionic electronic conductor, electronic conductivity is determined by the change in the electronic state of Ti ions. In LLTO, Ti exists in two oxidation states: Ti 4+ and Ti 3+ It can exist in the form of Ti 4+ Since it contains as a main component, its electronic conductivity is low in the initial state. However, if metal ions are doped or a high-temperature heat treatment process is performed, Ti 4+ Part of the ion is Ti 3+ It can be reduced to ions. The electron transition phenomenon occurring at this time significantly enhances the electron conductivity of LLTO. In particular, metal doping provides an electron source, promoting the reaction in which Ti⁴ is converted to Ti³. This reduction process enables the movement of electrons within LLTO, thereby increasing electron conductivity and allowing it to be utilized as a mixed ionic electron conductor with high ionic and electron conductivity.

[0137] In one embodiment of the present invention, the doped metal may be Y, Ce, Ta, Al, Mg, Ti, Fe, Zn, Ga, Br, B, Mn, Sc, Nb, W, Zr, Cr, Cu, Ge, Sn, Sr, or a combination thereof. In another example of the present invention, the mixed ionic electronic conductor may preferably be Ta, Al, Zn, Ga, or a combination thereof.

[0138]

[0139] The second aspect of the present invention is,

[0140] It comprises an electrode material layer; and a mixed ion electron conductor (MIEC) contained in the surface and internal pores of the electrode material layer, wherein the mixed ion electron conductor is a metal-doped LLZO (Li7La3Zr2O 12 ), LLZO, metal-doped LATP (Li 1+x Al x Ti 2-x (PO4)3) (0≤x≤0.5), LATP, metal-doped LLTO(Li 3y La 2 / 3-y TiO3) (0 <y≤0.16), LLTO, 및 이들의 조합으로 이루어진 것을 특징으로 하는, 혼합 이온 전자 전도체를 포함하는 전극을 제공한다.

[0141]

[0142] Detailed explanations have been omitted for parts that overlap with the first aspect of the present invention; however, the content described in the first aspect of the present invention may be applied equally even if such explanations are omitted in the second aspect.

[0143]

[0144] Hereinafter, an electrode comprising a mixed ion electron conductor according to the second aspect of the present invention will be described in detail.

[0145]

[0146] In one embodiment of the present invention, the doped metal may be Y, Ce, Ta, Al, Mg, Ti, Fe, Zn, Ga, Br, B, Mn, Sc, Nb, W, Zr, Cr, Cu, Ge, Sn, Sr, or a combination thereof. In another example of the present invention, the mixed ionic electronic conductor may preferably be Ta, Al, Zn, Ga, or a combination thereof.

[0147] In one embodiment of the present invention, the surface of the electrode material layer further comprises a coating layer having a thickness of 100 nm to 10 μm, and the coating layer may be composed of a mixed ion electron conductor. In another example of the present invention, the coating layer may have a thickness of 500 nm to 5 μm. The coating layer may simultaneously have an electron transport path for moving electrons and an ion transport path for moving lithium ions.

[0148] In one embodiment of the present invention, the mixed ion electronic conductor is 1.0 x 10 -8 Up to 1.0 x 10 -4 It can have an electronic conductivity of S / cm. In another example of the present invention, the electronic conductivity of the mixed ion electronic conductor is 1.0 x 10⁻⁶ -7 Up to 1.0 x 10 -5 It can be S / cm, and more preferably 1.0 x 10 -7 Up to 1.0 x 10 -6 It can be S / cm.

[0149] In one embodiment of the present invention, the mixed ion electronic conductor is 1.0 x 10 -6 Up to 1.0 x 10 -3 It can have an ionic conductivity of S / cm. In another example of the present invention, the ionic conductivity of the mixed ionic electron conductor is 1.0 x 10⁻⁶ -5 Up to 1.0 x 10 -4 It can be S / cm.

[0150] In one embodiment of the present invention, the mixed ion electron conductor has 1.0 mA / cm 2 A short circuit may not occur even at a current density above this level. In another example of the present invention, the mixed ion electronic conductor is preferably 1.5 mA / cm² 2 A short circuit may not occur even at current densities above this level, and more preferably at 2.0 mA / cm² 2 A short circuit may not occur even at the above current density. This is because the mixed ionic electronic conductor of the present invention has improved electrochemical stability as both ionic conductivity and electronic conductivity are simultaneously enhanced.

[0151] In one embodiment of the present invention, the void in the mixed ion electron conductor may be reduced. In another example of the present invention, 125 μm of the mixed ion electron conductor 3 In a volume (5㎛ x 5㎛ x 5㎛), it may be characterized by a reduction in gap volume of 5 to 50%. In another example of the present invention, preferably 125㎛ of the mixed ion electron conductor 3 It may be characterized by a reduction in gap volume of 10 to 40% in volume (5㎛ x 5㎛ x 5㎛). The gap may be filled with MIEC to reduce the gap volume. By filling the gap with MIEC, point contact between electrode materials is reduced, and electrochemical properties may be improved. By filling the gap with MIEC, an electron path for electrons or ions may be formed.

[0152]

[0153] The present invention can simultaneously improve the ionic conductivity and electronic conductivity of an electrode, prevent performance degradation during high-speed charging and discharging, improve capacity retention, and reduce interfacial resistance between the electrode and the solid electrolyte to improve the electrochemical stability of the battery, and thus can be considered to have industrial applicability.

Claims

1. A step of preparing a mixed ion electron conductor (MIEC) and an electrode material, respectively; and A step of combining a mixed ion electron conductor (MIEC) and an electrode material; Includes, A step of combining the above mixed ion electron conductor (MIEC) and electrode material; thereafter, A method for manufacturing an electrode comprising a mixed ion electron conductor, characterized in that the mixed ion electron conductor (MIEC) is fixed to the surface and internal pores of the electrode material to form a transmission path for electrons or ions.

2. In Paragraph 1, The step of compounding the above-mentioned mixed ion electronic conductor and electrode material; A step of mixing the mixed ion-electron conductor and electrode material by ball milling; and A step of sintering the above mixture; including, Method for manufacturing an electrode containing a mixed ion electron conductor.

3. In Paragraph 2, The step of mixing the above-mentioned mixed ion electron conductor and electrode material by ball milling; A method for manufacturing an electrode comprising a mixed ion electron conductor, characterized by mixing at a speed of 100 to 1000 rpm for 6 to 24 hours.

4. In Paragraph 2, The step of sintering the above mixture is, A method for manufacturing an electrode comprising a mixed ion electron conductor, performed at a temperature of 900 to 1500 ℃ for 6 to 30 hours.

5. In Paragraph 1, The step of compounding the above-mentioned mixed ion electronic conductor and electrode material; A step of preparing a mixed ionic electronic conductor as a sputtering target; and Step of depositing a mixed ion electron conductor through plasma discharge; including, Method for manufacturing an electrode containing a mixed ion electron conductor.

6. In Paragraph 1, The step of compounding the above-mentioned mixed ion electronic conductor and electrode material; A step of preparing a dispersion by dispersing a mixed ionic electronic conductor in a solvent; A step of immersing the electrode material in the above dispersion; A step of drying the electrode material immersed in the above dispersion; and A step of heat-treating the above electrode material at a temperature of 200 to 500 ℃; including, Method for manufacturing an electrode containing a mixed ion electron conductor.

7. In Paragraph 1, The step of compounding the above-mentioned mixed ion electronic conductor and electrode material; A step of preparing a dispersion by dispersing a mixed ionic electronic conductor in a solvent; A step of immersing the electrode material in the above dispersion; A step of applying a voltage of 20 to 50V to an electrode material immersed in the dispersion solution; and A step of heat-treating the above electrode material at a temperature of 200 to 500 ℃; including, Method for manufacturing an electrode containing a mixed ion electron conductor.

8. In Paragraph 1, The above mixed ionic electronic conductor is metal-doped LLZO(Li7La3Zr2O 12 ), LLZO, metal-doped LATP (Li 1+x Al x Ti 2-x (PO4)3) (0≤x≤0.5), LATP, metal-doped LLTO(Li 3y La 2 / 3-y TiO3) (0 <y≤0.16), LLTO, LLMnO (Li 0.34 La 0.55 MnO 3-z ) (0≤z≤1), Li a La b MeO3(Me = Ti, Cr, Mn, Fe, Co) (0 <a<2, 0<b<3), La 1-x Sr x MnO3(LSM) (0≤x≤0.5), SrCoO3, BaCoO3, La 0.6 Sr 0.4 A method for manufacturing an electrode comprising a mixed ion electron conductor characterized by being composed of CoO3, TiO2, Li3Si, NiO, ZnO, and combinations thereof.

9. In Paragraph 8, A method for manufacturing an electrode comprising a mixed ion electron conductor, characterized in that the doped metal is Y, Ce, Ta, Al, Mg, Ti, Fe, Zn, Ga, Br, B, Mn, Sc, Nb, W, Zr, Cr, Cu, Ge, Sn, Sr, or a combination thereof.

10. Electrode layer; and Mixed ion electron conductors (MIEC) contained in the surface and internal pores of the electrode material layer; Includes, The above mixed ionic electronic conductor is metal-doped LLZO(Li7La3Zr2O 12 ), LLZO, metal-doped LATP (Li 1+x Al x Ti 2-x (PO4)3) (0≤x≤0.5), LATP, metal-doped LLTO(Li 3y La 2 / 3-y TiO3) (0 <y≤0.16), LLTO, 및 이들의 조합으로 이루어진 것을 특징으로 하는, 혼합 이온 전자 전도체를 포함하는 전극.

11. In Paragraph 10, A method for manufacturing an electrode comprising a mixed ion electron conductor, characterized in that the doped metal is Y, Ce, Ta, Al, Mg, Ti, Fe, Zn, Ga, Br, B, Mn, Sc, Nb, W, Zr, Cr, Cu, Ge, Sn, Sr, or a combination thereof.

12. In Paragraph 10, The surface of the electrode material layer further comprises a coating layer having a thickness of 100 nm to 10 μm, and The electrode comprising a mixed ion electron conductor, wherein the coating layer is composed of a mixed ion electron conductor.

13. In Paragraph 10, The above mixed ionic electronic conductor is 1.0 x 10 -8 Up to 1.0 x 10 -4 An electrode comprising a mixed ionic electron conductor having an electron conductivity of S / cm.

14. In Paragraph 10, The above mixed ionic electronic conductor is 1.0 x 10 -6 Up to 1.0 x 10 -3 An electrode comprising a mixed ion-electron conductor having an ion conductivity of S / cm.

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