JP2018029046A - All-solid lithium battery and method for manufacturing all-solid lithium battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an all-solid lithium battery and a method for manufacturing the all-solid lithium battery, capable of reducing interface resistance between an electrode layer and an electrolyte layer, and achieving faster charge/discharge.SOLUTION: An all-solid lithium battery is a thin film type and laminated with a solid electrolyte layer between a positive electrode layer including a positive electrode active material and a negative electrode layer including a negative electrode active material. When a voltage value between the positive electrode layer and the negative electrode layer is not less than 4.5 V and not more than 4.75 V, a resistance value in an interface between the positive electrode layer and the solid electrolyte layer is not less than 2 Ωcmand not more than 6 Ωcm.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a thin film type all solid lithium battery and a method for producing an all solid lithium battery.

  In recent years, portable electronic devices such as notebook PCs (Personal Computers), mobile phones, and smartphones have become widespread, and lithium-ion batteries having advantages such as high voltage, high energy density, and light weight as power sources. In addition, use of a large-sized lithium ion battery is expected as an in-vehicle application for an electric vehicle or a hybrid vehicle, or as a stationary storage battery for an electric power system. In recent years, all solid lithium batteries having high safety, in which all members including an electrolyte are made of nonflammable solids, are attracting attention.

  However, the all-solid-state lithium battery has a large interface resistance at the interface between the electrode layer and the electrolyte layer, which is a problem for practical use. As described above, since the interface resistance between the electrode layer and the electrolyte layer is large, it is difficult to speed up the charge / discharge of the all-solid lithium battery.

  The interface resistance between the electrode layer and the electrolyte layer is considered to originate from the space charge layer formed at the interface. Therefore, recently, it has been proposed to suppress the space charge layer by inserting a foreign substance at the interface and reduce the interface resistance between the electrode layer and the electrolyte layer (see, for example, Non-Patent Document 1). .

C. Yada, A. Ohmori, K. Ide, H. Yamasaki, T. Kato, T. Saito, F. Sagane, and Y. Iriyama, Adv. Energy Mater. 4, 1301416 (2014)

However, even when the method described in Non-Patent Document 1 is used, the interface resistance between the electrode layer and the electrolyte layer is at least about 2000 Ωcm ² at a voltage of 4.7 V, so that charging / discharging is speeded up. It was difficult.

  An object of the present invention has been made in view of the above problems, and is an all-solid lithium battery and all-solid lithium capable of reducing the interface resistance between the electrode layer and the electrolyte layer and speeding up charging and discharging. It aims at providing the manufacturing method of a battery.

An all solid lithium battery according to the present invention is a thin film type all solid lithium battery in which a solid electrolyte layer is laminated between a positive electrode layer containing a positive electrode active material and a negative electrode layer containing a negative electrode active material, the positive electrode layer When the voltage value between the positive electrode layer and the negative electrode layer is 4.5 V or more and 4.75 V or less, the resistance value at the interface between the positive electrode layer and the solid electrolyte layer is ² Ωcm ² or more and 6 Ωcm ² or less. Is.

  As described above, according to the present invention, charge / discharge can be speeded up by reducing the interface resistance between the electrode layer and the electrolyte layer.

It is a schematic sectional drawing which shows an example of a structure of the all-solid-state lithium battery which concerns on this Embodiment. It is the schematic which shows an example of a structure of the battery manufacture evaluation apparatus which produces the all-solid-state lithium battery of FIG. It is the schematic which shows the measurement result of the alternating current impedance in the all-solid-state lithium battery of Example 1 and Comparative Example 1. FIG. 3 is a schematic diagram showing the measurement results of the interface resistance between the positive electrode layer and the solid electrolyte layer in the all solid lithium battery of Example 1. It is the schematic which shows the profile of the X-ray CTR scattering in the comparative example 2 and the comparative example 3. 6 is a schematic view showing an arrangement state of each atomic layer constituting the positive electrode active material of Comparative Example 2 and Comparative Example 3. FIG. FIG. 3 is a schematic diagram showing the relationship between the charge / discharge cycle and the battery capacity in the all solid lithium battery of Example 1.

Embodiment.
[All-solid lithium battery]
Hereinafter, an all-solid-state lithium battery according to an embodiment of the present invention will be described. As the all-solid-state lithium battery, a thin-film type in which the respective layers constituting the all-solid-state lithium battery are formed in a thin film and stacked, and a bulk type in which fine particles are stacked have been proposed. It is intended for all-solid-state lithium batteries.

[Configuration of all-solid lithium battery]
FIG. 1 is a schematic cross-sectional view showing an example of the configuration of an all-solid lithium battery 1 according to the present embodiment. As shown in FIG. 1, the all solid lithium battery 1 includes a substrate 2, a current collector layer 3, a positive electrode layer 4, a solid electrolyte layer 5, and a negative electrode layer 6.

(substrate)
The substrate 2 serves as a base for laminating the current collector layer 3, the positive electrode layer 4, the solid electrolyte layer 5, and the negative electrode layer 6. As the substrate 2, for example, a strontium titanate (SrTiO ₃ ) substrate doped with niobium (Nb) and made conductive, an Nb: SrTiO ₃ substrate (hereinafter referred to as “STO substrate” as appropriate) is used. Note that the substrate 2 is not limited to the above-described example, and for example, a metal plate, a glass substrate, a plastic substrate, or the like may be used.

(Current collector layer)
The current collector layer 3 is a layer formed by a current collector. As the current collector, a known metal that can be used as a current collector for an all-solid-state battery, or a layer in which a layer containing such a metal is laminated on a substrate such as ceramics can be used. The shape of the current collector is not particularly limited, and a foil shape, a plate shape, a mesh shape, or the like can be applied. In the present embodiment, LaNiO ₃ is used as a current collector.

(Positive electrode layer)
In the positive electrode layer 4, a positive electrode active material layer containing a positive electrode active material is formed on the current collector layer 3. The positive electrode active material layer includes, for example, a positive electrode active material and a binder. As the positive electrode active material, a lithium composite oxide that can be used in an all solid lithium battery or an intercalation compound containing lithium can be used as appropriate.

Specific examples of such a lithium composite oxide include LiCoO ₂ , LiNiO ₂ , LiNi _y Co _1-y O ₂ (where x and y vary depending on the charge / discharge state of the battery), LiFePO ₄ , LiMnPO ₄ , Examples include LiNiMnPO ₄ , LiMn ₂ O ₄ , LiNi _0.5 Mn _1.5 O ₄ (hereinafter, appropriately referred to as “LNMO”) in which a part of Mn of LiMn ₂ O ₄ is substituted with Ni.

  Such a lithium composite oxide is a particularly preferable material because it can generate a high voltage when used as a positive electrode active material and has an excellent energy density. In this embodiment, LNMO capable of generating a high voltage of about 5 V is used as the positive electrode active material.

(Negative electrode layer)
In the negative electrode layer 6, a negative electrode active material layer containing a negative electrode active material is formed on a current collector layer (not shown). The negative electrode active material layer includes, for example, a negative electrode active material and a binder. Examples of the negative electrode active material include carbon materials, silicon materials, crystalline and amorphous metal oxides that can be used in all-solid lithium batteries, metals that can form an alloy with lithium, or such metals. An alloy compound or the like can be used as appropriate. In this embodiment mode, Li is used as the negative electrode active material.

(Solid electrolyte layer)
The solid electrolyte layer 5 is a layer through which ions such as lithium ions moving between the positive electrode layer 4 and the negative electrode layer 6 are conducted. For the solid electrolyte layer 5, a known solid electrolyte that can be used in an all-solid lithium battery can be appropriately used. Examples of such a solid electrolyte include lithium phosphate oxynitride (LiPON). In addition, for example, Li ₃ PO ₄ , LiLaTiO ₃ (common name, LLTO), Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ), LiTaO ₃ , LiNbO ₃ , LiI, a sulfur-based Li ion conductor, or a Li polymer such as a solid polymer. ^{What made +} ion a conductive seed (movable ion) may be used as a solid electrolyte. In the present embodiment, Li ₃ PO ₄ is used as the solid electrolyte. Note that the thickness of the solid electrolyte layer 5 is, for example, 5 to 1000 nm, more specifically, about 300 nm.

[Battery manufacturing evaluation system]
FIG. 2 is a schematic diagram illustrating an example of the configuration of the battery manufacturing evaluation apparatus 100 that produces the all solid lithium battery 1 of FIG. As shown in FIG. 2, the battery manufacturing evaluation apparatus 100 includes a film formation chamber 10, an evaluation chamber 20, and a sample preparation chamber 30. Each chamber of the battery manufacturing evaluation apparatus 100 is connected to an ultra-high vacuum transfer mechanism 40 having an atmospheric pressure of about 10 ⁻⁸ Pa. Thereby, in battery manufacturing evaluation apparatus 100, preparation, evaluation, and analysis of all solid lithium battery 1 can be performed, without touching air.

(Deposition room)
The film forming chamber 10 is a chamber for forming each layer of the all-solid-state lithium battery 1 using a pulsed laser deposition (PLD) method or a vacuum evaporation method. In the film formation chamber 10, a current collector preparation part 11 for forming the current collector layer 3 using the PLD method, a positive electrode preparation part 12 for forming the positive electrode layer 4 using the PLD method, and a PLD method are used. There are provided a solid electrolyte preparation section 13 for forming the solid electrolyte layer 5 and a negative electrode preparation section 14 for forming the negative electrode layer 6 using a vacuum deposition method.

(Evaluation room)
The evaluation chamber 20 is a chamber for evaluating the electrochemical characteristics of the all solid lithium battery 1 produced in the film formation chamber 10. In the present embodiment, as an evaluation of the electrochemical characteristics of the all solid lithium battery 1, for example, AC impedance in the all solid lithium battery 1 is measured.

(Sample preparation room)
The sample preparation chamber 30 is a chamber for preparing a sample required when each layer is formed in the film formation chamber 10.

  In the battery manufacturing evaluation apparatus 100 shown in FIG. 2, the substrate is transported from one direction, for example, from the left direction, and each layer is sequentially formed by each production unit. This order is related to the order shown in the figure. The order of film formation can be freely selected.

[Method for producing all-solid-state lithium battery]
Next, a method for producing the all solid lithium battery 1 according to the present embodiment will be described. First, the substrate 2 is mounted on the substrate holder, and a mask holder provided with a collector layer deposition mask is mounted on the substrate holder on which the substrate 2 is mounted. Then, the substrate 2 mounted on the substrate holder and the mask holder is transported to the current collector preparation unit 11 by the transport mechanism 40, and the current collector layer 3 is formed on the substrate 2 using the PLD method.

  Next, the current collector layer deposition mask mounted on the mask holder is switched to the positive electrode layer deposition mask. Then, the substrate 2 on which the current collector layer 3 is formed is transported to the positive electrode preparation unit 12 by the transport mechanism 40, and the positive electrode layer 4 is formed on the current collector layer 3 using the PLD method.

  Next, the positive electrode layer deposition mask mounted on the mask holder is switched to the solid electrolyte layer deposition mask. Then, the substrate 2 on which the positive electrode layer 4 is formed is transferred to the solid electrolyte preparation unit 13 by the transfer mechanism 40, and the solid electrolyte layer 5 is formed on the positive electrode layer 4 using the PLD method.

  Thus, when forming each layer, the interface state between the layers can be kept good by using the PLD method under vacuum. In particular, when the solid electrolyte layer 5 is formed on the positive electrode layer 4, the interface between the positive electrode layer 4 and the solid electrolyte layer 5 can be flattened, and mixing of foreign substances can be suppressed. it can.

  Finally, the solid electrolyte layer deposition mask mounted on the mask holder is switched to the negative electrode layer deposition mask. Then, the substrate 2 on which the solid electrolyte layer 5 is formed is transferred to the negative electrode preparation unit 14 by the transfer mechanism 40, and the negative electrode layer 6 is formed on the solid electrolyte layer 5 using a vacuum deposition method. Thereby, the all-solid-state lithium battery 1 in which the current collector layer 3, the positive electrode layer 4, the solid electrolyte layer 5, and the negative electrode layer 6 are laminated on the substrate 2 is manufactured.

[Measurement method of AC impedance]
Next, a method for measuring AC impedance in the all solid lithium battery 1 will be described. When measuring the alternating current impedance of the all-solid-state lithium battery 1, for example, in the evaluation chamber 20, the alternating current impedance in the set frequency range is measured, and based on the measurement result, between the positive electrode layer 4 and the solid electrolyte layer 5. Get the interface resistance. For example, a measuring instrument such as a potentio / galvanostat and a frequency response analyzer is used to measure the AC impedance of the all-solid-state lithium battery 1.

  Specifically, for example, using a potentio / galvanostat and a frequency response analyzer, the voltage between the positive electrode layer 4 and the negative electrode layer 6 is set at a set voltage such as 4.7 V under a set condition such as a frequency of 1 MHz to 1 Hz. The AC impedance Z of the all solid lithium battery 1 in a certain case is measured. The measurement results are plotted on a Nyquist diagram with the horizontal axis representing the real component Z ′ of the AC impedance Z and the vertical axis representing the imaginary component Z ″ of the AC impedance Z.

  Here, the impedance response to the frequency is usually different in the positive electrode layer 4, the interface between the positive electrode layer 4 and the solid electrolyte layer 5, and the solid electrolyte layer 5. For example, in a high frequency region of about 1 MHz to 10 kHz, the solid electrolyte The impedance due to the layer 5 mainly appears, and the impedance due to the positive electrode layer 4 mainly appears in a low frequency region of about 10 Hz. In the region between the high frequency region and the low frequency region of about 1 kHz to 100 Hz, impedance due to the interface between the positive electrode layer 4 and the solid electrolyte layer 5 appears.

  Therefore, the interface resistance between the positive electrode layer 4 and the solid electrolyte layer 5 can be acquired by detecting the real component of the impedance that appears in the region between the high frequency region and the low frequency region.

[Analysis method by X-ray CTR scattering]
Next, an analysis method of the all-solid-state lithium battery 1 by X-ray CTR (Crystal Truncation Rod) scattering will be described. When analyzing the all-solid-state lithium battery 1 using X-ray CTR scattering, for example, X-ray CTR scattering measurement is performed in a synchrotron radiation facility, and a scattering profile roughly corresponding to a part of the all-solid-state lithium battery 1 is acquired. . And based on the acquired scattering profile, element distribution in the specific layer of the all-solid-state lithium battery 1 is analyzed.

  Hereinafter, although the example demonstrates the all-solid-state lithium battery 1 by this Embodiment concretely, this Embodiment is not limited only to these Examples.

[Example 1]
(Preparation of current collector layer)
First, an SrTiO ₃ (STO) substrate doped with Nb and having a crystal orientation of (100) was prepared as the substrate 2. Next, a layer made of LaNiO ₃ having a thickness of 20 nm was formed on the STO substrate by using the PLD method, and the current collector layer 3 was produced. Each condition of the PLD method at this time is as follows.
Target composition: LaNiO ₃
・ Oxygen partial pressure: 100 mTorr
-Substrate temperature: 650 ° C
Laser condition: KrF excimer 5 Hz, 1 J / cm ²

(Preparation of positive electrode layer)
Next, a layer made of LNMO having a thickness of 60 nm was formed on the current collector layer 3 using the PLD method, and the positive electrode layer 4 was manufactured. Each condition of the PLD method at this time is as follows.
Target composition: Li _1.2 (Ni _0.5 Mn _1.5 ) O ₄
・ Oxygen partial pressure: 100 mTorr
-Substrate temperature: 600 ° C
Laser condition: KrF excimer 5 Hz, 1 J / cm ²

(Preparation of solid electrolyte layer)
Next, a layer made of Li ₃ PO ₄ having a thickness of 500 nm was formed on the positive electrode layer 4 using the PLD method, and the solid electrolyte layer 5 was produced. Each condition of the PLD method at this time is as follows.
Target composition: Li ₃ PO ₄
-Oxygen partial pressure: Vacuum-Substrate temperature: Room temperature-Laser conditions: ArF excimer 20 Hz, 1 J / cm ²

(Preparation of negative electrode layer)
Finally, Li is vapor-deposited on the solid electrolyte layer 5 using a resistance heating type vacuum vapor deposition method to produce a negative electrode layer 6 having a thickness of 500 nm, and an all solid lithium battery 1 having a theoretical capacity value of 147 mAh / g is obtained. Produced.

[Comparative Example 1]
Except for inserting MgO, which is a foreign substance, at the interface between the positive electrode layer 4 and the solid electrolyte layer 5, everything was the same as in Example 1.

[Comparative Example 2]
A substrate in which only the positive electrode layer 4 and the solid electrolyte layer 5 were formed by using the same PLD method as in Example 1 was produced on the substrate 2.

[Comparative Example 3]
A substrate in which only the positive electrode layer 4 was formed on the substrate 2 by using the same PLD method as in Example 1 was produced.

[Measurement of AC impedance]
FIG. 3 is a schematic diagram showing the measurement result of the AC impedance Z in the all solid lithium battery 1 of Example 1 and Comparative Example 1. FIG. 3A shows the measurement result of the AC impedance Z in the all-solid-state lithium battery 1 of Example 1. FIG. 3B shows the real component Z ′ of the impedance Z in FIG. This is an enlarged portion of 80 kΩ. FIG. 3C shows the measurement result of the portion where the real component Z ′ of the impedance Z is 40 kΩ to 80 kΩ among the measurement results of the AC impedance Z in the all solid lithium battery 1 of Comparative Example 1.

In FIG. 3, the impedance component indicated by symbol A is derived from Li ₃ PO ₄ of the solid electrolyte layer 5, and the impedance component indicated by symbol B is present at the interface between the positive electrode layer 4 and the solid electrolyte layer 5. This is the derived impedance component. The impedance component indicated by symbol C is derived from the LNMO of the positive electrode layer 4.

  From the results shown in FIGS. 3A and 3B, in Example 1, the interface resistance was about 3.9 kΩ. On the other hand, from the results shown in FIG. 3C, in Comparative Example 1, the interface resistance was about 20 kΩ. From these results, it can be understood that the interfacial resistance between the positive electrode layer 4 and the solid electrolyte layer 5 is increased by mixing different substances between the positive electrode layer 4 and the solid electrolyte layer 5.

[Change in interface resistance against voltage]
FIG. 4 is a schematic diagram showing the measurement results of the interface resistance between the positive electrode layer 4 and the solid electrolyte layer 5 in the all solid lithium battery 1 of Example 1. Here, a plurality of all solid lithium batteries 1 of Example 1 were produced under the same conditions, and all solid lithium batteries 1 of Sample A and Sample B were obtained. 4A shows the measurement result of the interface resistance in the all-solid lithium battery 1 of sample A, and FIG. 4B shows the measurement result of the interface resistance in the all-solid lithium battery 1 of sample B.

As shown in FIGS. 4A and 4B, the interfacial resistance between the positive electrode layer 4 and the solid electrolyte layer 5 is between 4.5 V and 4.75 V, which is near the operating voltage of LNMO. 2Ωcm was greater than or equal to ² 6Ωcm ² below. Since the operating voltage of LNMO is usually about 4.7 V, the voltage range is set to “4.5 V or more and 4.75 V or less” in consideration of the actual operating voltage.

Here, the interface resistance of the conventional all-solid-state lithium battery is about 200 to 2000 Ωcm ² , and the interface resistance when an electrolytic solution is used for the electrolyte layer is about 30 to 90 Ωcm ² . Therefore, in the all-solid-state lithium battery 1 according to the present embodiment, the interface resistance between the positive electrode layer 4 and the solid electrolyte layer 5 is reduced to the interface between the conventional all-solid-state lithium battery and the lithium battery using the electrolyte in the electrolyte layer. It can be reduced more than the resistance.

[Analysis by X-ray CTR scattering]
FIG. 5 is a schematic diagram showing profiles of X-ray CTR scattering in Comparative Example 2 and Comparative Example 3. As shown in FIG. 5, Comparative Example 2 and Comparative Example 3 produced using the PLD method show similar profiles, respectively. From this, it can be seen that the LNMO film formation state of the positive electrode layer 4 is not affected by the solid electrolyte layer 5. That is, it can be seen that the interface between the positive electrode layer 4 and the solid electrolyte layer 5 manufactured using the PLD method is in a good state.

  FIG. 6 is a schematic diagram illustrating an arrangement state of each atomic layer constituting the positive electrode active materials of Comparative Example 2 and Comparative Example 3. The graph shown in FIG. 6 can be obtained based on the X-ray CTR scattering profile of FIG. 6A shows the electron density distribution of each atomic layer of the positive electrode active material in Comparative Example 2, and FIG. 6B shows the electron density distribution of each atomic layer of the positive electrode active material in Comparative Example 3. In FIG. 6A and FIG. 6B, the horizontal axis indicates the position in the direction perpendicular to the interface between the substrate 2 and the positive electrode layer 4, the left side is toward the substrate 2 and the right side is toward the solid electrolyte layer 5. Direction. Moreover, the vertical axis | shaft in FIG.6 (b) shows the electron density in a certain position. FIG. 6C shows a model of the crystal structure of each atomic layer based on the electron density distribution shown in FIG.

  As shown in FIG. 6A, in Comparative Example 2, LNMO, which is the positive electrode active material of the positive electrode layer 4, has an atomic layer of “Mn”, “MnLi”, and “O” constituting the LNMO. From the side, it can be seen that “O”, “Mn”, “O”, and “MnLi” are periodically arranged in this order. Moreover, the average distance between each atomic layer of LNMO in Comparative Example 2 is 1.10 ± 0.03 mm between Mn—O, 2.36 ± 0.04 mm between Mn—MnLi, and 4 between Mn—Mn. .72 ± 0.02 cm. Further, as shown in FIG. 6C, it can be seen that the LNMO of the positive electrode layer 4 is formed by growing in a state where the crystal orientations are aligned.

  On the other hand, as shown in FIG. 6B, in Comparative Example 3, as in Comparative Example 2, the atomic layers constituting the LNMO of the positive electrode layer 4 are periodically arranged, and It can be seen that the peak indicating the electron density appears in the same size as in Comparative Example 2. In addition, the average distance between each atomic layer of LNMO in Comparative Example 3 is 1.13 ± 0.05 mm between Mn—O, 2.42 ± 0.06 mm between Mn—MnLi, and 4 between Mn—Mn. .76 ± 0.03 cm.

  As described above, in Comparative Example 2 and Comparative Example 3, the arrangement of the atomic layers constituting the LNMO and the average distance between the atomic layers show substantially the same results. Therefore, the structure of the LNMO of the positive electrode layer 4 is It can be seen that the solid electrolyte layer 5 is not affected.

[Capacity change with charge / discharge cycle]
FIG. 7 is a schematic diagram showing the relationship between the charge / discharge cycle and the battery capacity in the all-solid-state lithium battery 1 of Example 1. Here, charging and discharging were performed by supplying a current that can be charged at 3600 C, that is, a current that can be fully charged in 1 second, to the all-solid-state lithium battery 1 having a theoretical capacity value of 147 mAh / g. As shown in FIG. 7, in the all solid lithium battery 1 of Example 1, charging and discharging were performed at an ultrafast rate of 3600 C for 1 to 100 cycles. A capacity of 73 mAh / g, which is about 50% of the capacity, was obtained. Further, even when such charge / discharge is repeated 100 cycles, no decrease in capacity is observed. From this result, it can be seen that the all-solid-state lithium battery 1 according to the present embodiment can repeat the ultra-high speed charge / discharge cycle with almost no deterioration.

  Here, the conventional all solid lithium battery can be charged and discharged only at a rate of about 10 C at the maximum. Therefore, from the above-described results, the all-solid lithium battery 1 according to the present embodiment is charged so that at least a capacity of about 50% of the theoretical capacity is obtained at a rate of 3600 C, which is significantly faster than the conventional all-solid lithium battery. And discharging can be performed.

As described above, the all solid lithium battery 1 according to the present embodiment is a thin film type in which the solid electrolyte layer 5 is laminated between the positive electrode layer 4 including the positive electrode active material and the negative electrode layer 6 including the negative electrode active material. The resistance at the interface between the positive electrode layer 4 and the solid electrolyte layer 5 when the voltage value between the positive electrode layer 4 and the negative electrode layer 6 is 4.5 V or more and 4.75 V or less in the all solid lithium battery 1. The value is ² Ωcm ² or more and 6 Ωcm ² or less. Thereby, in this Embodiment, the interface resistance between the positive electrode layer 4 and the solid electrolyte layer 5 can be reduced rather than the lithium battery using the conventional all-solid-state lithium battery and electrolyte solution. In addition, since the interface resistance between the positive electrode layer 4 and the solid electrolyte layer 5 in the all-solid-state lithium battery 1 can be reduced, at least at a theoretical capacity, for example, at a rate that is significantly faster than conventional, such as charge / discharge at 3600C. Charging and discharging to obtain a capacity of about 50% can be performed.

  Moreover, the all solid lithium battery 1 according to the present embodiment is a thin film type all solid lithium in which a solid electrolyte layer 5 is laminated between a positive electrode layer 4 containing a positive electrode active material and a negative electrode layer 6 containing a negative electrode active material. In the battery 1, each atomic layer constituting the positive electrode active material is periodically formed in a direction perpendicular to the interface between the positive electrode layer 4, the substrate 2 on which the positive electrode layer 4, the solid electrolyte layer 5 and the negative electrode layer 6 are laminated. Has been placed. Thereby, the interface between the positive electrode layer 4 and the solid electrolyte layer 5 can be formed flat to maintain a good state, thereby reducing the interface resistance between the positive electrode layer 4 and the solid electrolyte layer 5. be able to. Further, since the interface resistance between the positive electrode layer 4 and the solid electrolyte layer 5 in the all-solid-state lithium battery 1 can be reduced, charging that obtains at least a capacity of about 50% of the theoretical capacity at a rate significantly faster than the conventional capacity. And discharging can be performed.

  Furthermore, the all solid lithium battery 1 according to the present embodiment is a thin film type all solid lithium in which a solid electrolyte layer 5 is laminated between a positive electrode layer 4 containing a positive electrode active material and a negative electrode layer 6 containing a negative electrode active material. A positive electrode layer 4, a solid electrolyte layer 5, and a negative electrode layer 6 are stacked on a substrate 2 that is a battery 1 and has a crystal orientation of (100) or (111). Thereby, the interface between the positive electrode layer 4 and the solid electrolyte layer 5 can be formed flat to maintain a good state, thereby reducing the interface resistance between the positive electrode layer 4 and the solid electrolyte layer 5. be able to. Further, since the interface resistance between the positive electrode layer 4 and the solid electrolyte layer 5 in the all-solid-state lithium battery 1 can be reduced, charging that obtains at least a capacity of about 50% of the theoretical capacity at a rate significantly faster than the conventional capacity. And discharging can be performed.

  Furthermore, the manufacturing method of the all-solid-state lithium battery 1 according to the present embodiment is a thin film type in which a solid electrolyte layer 5 is laminated between a positive electrode layer 4 containing a positive electrode active material and a negative electrode layer 6 containing a negative electrode active material. And a step of forming a current collector layer 3 on a substrate 2 using a pulse laser deposition method, and a pulse laser deposition method on the current collector layer 3. The step of forming the positive electrode layer 4, the step of forming the solid electrolyte layer 5 on the positive electrode layer 4 using a pulse laser deposition method, and the negative electrode layer 6 on the solid electrolyte layer 5 using a vacuum deposition method All steps are performed under vacuum. Thereby, the interface between the positive electrode layer 4 and the solid electrolyte layer 5 can be formed flat, and mixing of foreign substances can be suppressed and a good state can be maintained, whereby the positive electrode layer 4 and the solid electrolyte layer 5 Interfacial resistance can be reduced.

  According to the present invention, as described above, the interfacial resistance between the positive electrode layer 4 and the solid electrolyte layer 5 in the all-solid lithium battery 1 is reduced, so that the charge / discharge time of the conventional all-solid lithium battery is significantly increased. Thus, charging and discharging can be performed at a rate of 3600 C, which is a high speed, that is, at a rate of about 50% of the theoretical capacity at 1 second.

  Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and various modifications and applications can be made without departing from the gist of the present invention. For example, in the present embodiment, the case where the substrate 2 with the crystal orientation (100) is used has been described. However, the present invention is not limited to this, and the above description is given even when the substrate 2 with the crystal orientation (111) is used. Characteristics similar to the characteristics can be obtained. Further, for example, a substrate 2 having a crystal orientation (010) or (001) equivalent to the orientation (100) may be used.

In this embodiment, the case where LNMO is applied as the positive electrode active material has been described as an example. However, the present invention is not limited to this, and for example, LiCoO ₂ may be applied as the positive electrode active material.

  DESCRIPTION OF SYMBOLS 1 All-solid-state lithium battery, 2 board | substrate, 3 Current collector layer, 4 Positive electrode layer, 5 Solid electrolyte layer, 6 Negative electrode layer, 10 Film-forming chamber, 11 Current collector preparation part, 12 Positive electrode preparation part, 13 Solid electrolyte preparation part , 14 Negative electrode preparation part, 20 evaluation room, 30 sample preparation room, 40 conveyance mechanism, 100 battery manufacturing evaluation apparatus.

Claims (10)

A thin film type all solid lithium battery in which a solid electrolyte layer is laminated between a positive electrode layer containing a positive electrode active material and a negative electrode layer containing a negative electrode active material,
When the voltage value between the positive electrode layer and the negative electrode layer is 4.5 V or more and 4.75 V or less, the resistance value at the interface between the positive electrode layer and the solid electrolyte layer is ² Ωcm ² or more and 6 Ωcm ² or less. An all-solid-state lithium battery. A thin film type all solid lithium battery in which a solid electrolyte layer is laminated between a positive electrode layer containing a positive electrode active material and a negative electrode layer containing a negative electrode active material,
Each atomic layer constituting the positive electrode active material is periodically arranged in a direction perpendicular to the interface between the positive electrode layer, the solid electrolyte layer, and the negative electrode layer, and the positive electrode layer. An all-solid lithium battery. A thin film type all solid lithium battery in which a solid electrolyte layer is laminated between a positive electrode layer containing a positive electrode active material and a negative electrode layer containing a negative electrode active material,
An all solid lithium battery, wherein the positive electrode layer, the solid electrolyte layer, and the negative electrode layer are laminated on a substrate having a crystal orientation of (100) or (111). The positive electrode layer is
The all-solid-state lithium battery according to any one of claims 1 to 3, comprising LNMO, which is a lithium composite oxide, as the positive electrode active material. The all-solid-state lithium battery according to claim 1 or 2, wherein a crystal orientation of a substrate on which the positive electrode layer, the solid electrolyte layer, and the negative electrode layer are stacked is (100) or (111). Each atomic layer constituting the positive electrode active material is periodically arranged in a direction perpendicular to the interface between the positive electrode layer, the substrate on which the solid electrolyte layer and the negative electrode layer are laminated, and the positive electrode layer. The all-solid-state lithium battery according to claim 1 or 3, characterized in that When the voltage value between the positive electrode layer and the negative electrode layer is 4.5 V or more and 4.75 V or less, the resistance value at the interface between the positive electrode layer and the solid electrolyte layer is ² Ωcm ² or more and 6 Ωcm ² or less. The all-solid-state lithium battery according to claim 2, wherein: A method for producing a thin-film type all-solid lithium battery in which a solid electrolyte layer is laminated between a positive electrode layer containing a positive electrode active material and a negative electrode layer containing a negative electrode active material,
Forming a current collector layer on a substrate using a pulsed laser deposition method;
Forming the positive electrode layer on the current collector layer using a pulse laser deposition method;
Forming the solid electrolyte layer on the positive electrode layer using a pulse laser deposition method;
Forming the negative electrode layer on the solid electrolyte layer using a vacuum deposition method,
All the processes are performed under vacuum, The manufacturing method of the all-solid-state lithium battery characterized by the above-mentioned. The substrate is
The method for producing an all-solid-state lithium battery according to claim 8, wherein the crystal orientation is (100). The substrate is
The method for producing an all-solid-state lithium battery according to claim 8, wherein the crystal orientation is (111).

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