TW201941486A - Secondary cell and method for manufacturing secondary cell - Google Patents

Abstract

The present invention provides a technique for improving the performance of a secondary battery. The secondary battery (100) of the present embodiment comprises: a first electrode (21); a second electrode (22); a first layer (11) that is placed between the first electrode (21) and the second electrode (22), and that contains a first n-type oxide semiconductor material; a second layer (12) taht is placed on the first layer (11), and that contains a second n-type oxide semiconductor material and a first insulation material; a third layer (13) that is placed on the second layer (12), and that contains an aluminum compound; and a fourth layer (14) that is placed on the third layer (13), and that contains a p-type oxide semiconductor material.

Description

Secondary battery and manufacturing method of secondary battery

The present invention relates to a technology for improving the performance of a secondary battery.

Patent Document 1 discloses a power storage element including a power storage layer between a first electrode and a second electrode. The power storage layer includes a mixture of an insulating material and n-type semiconductor particles. A p-type semiconductor layer is disposed between the power storage layer and the second electrode. Further, a leakage suppression layer is disposed between the p-type semiconductor layer and the power storage layer. The earth leakage suppression layer is composed of at least one selected from silicon dioxide, aluminum oxide, and magnesium oxide.

Patent Document 2 discloses a power storage element including a power storage layer between a first electrode and a second electrode. The power storage layer includes a mixture of an insulating material and n-type semiconductor particles. A p-type semiconductor layer is disposed between the power storage layer and the second electrode. Further, a diffusion suppression layer having a resistivity of 1000 μΩ · cm or less is disposed between the first electrode and the power storage layer. The diffusion suppression layer is formed of a nitride, a carbide, or a boride.
[Prior technical literature]
[Patent Literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 2016-82125.
Patent Document 2: Japanese Patent Application Laid-Open No. 2016-91931.

[Problems to be Solved by the Invention]

For such a secondary battery, further improvement in performance is expected.

An object of the present invention is to provide a technology for improving the performance of a secondary battery.
[Means to solve the problem]

A secondary battery system according to this embodiment includes: a first electrode; a second electrode; and a first layer, which is disposed between the first electrode and the second electrode, and includes a first n-type oxide. Semiconductor material; the second layer is disposed on the first layer and includes a second n-type oxide semiconductor material and a first insulating material; the third layer is disposed on the second layer and includes aluminum A compound; and a fourth layer, which is disposed on the third layer and includes a p-type oxide semiconductor material. Thereby, the performance of the secondary battery can be improved.

In the above-mentioned secondary battery, it is preferable that the fifth layer including the second insulating material is disposed between the second layer and the third layer or between the third layer and the fourth layer. .

In the above-mentioned secondary battery, it is preferable that the fifth layer including the second insulating material is disposed between the second layer and the third layer, and the sixth layer including the aluminum compound is disposed between the second layer and the second layer. Between the aforementioned fifth layer.

In the secondary battery described above, it is preferable that the aluminum compound system includes Al ₂ O ₃ (alumina), AlN (aluminum nitride), AlON (alumina oxynitride), Al (OH) ₃ (aluminum hydroxide), and At least one of SiAlON (silicon-alumina nitride).

In the above secondary battery, the thickness of the third layer is preferably 1 nm to 40 nm.

In the above secondary battery, the thickness of the sixth layer is preferably 1 nm to 40 nm.

In the secondary battery described above, it is preferable that the fifth layer is a layer in which SiO _x as the second insulating material is taken as a main component, and a metal oxide is added to the fifth layer.

In the above-mentioned secondary battery, it is preferable that the metal oxide is SnO _x .

In the above secondary battery, it is preferable that the third layer system contains Si.

In the above secondary battery, it is preferable that the sixth layer system contains Si.

In the secondary battery described above, it is preferable that the first insulating material is SiO _x and the second n-type oxide semiconductor material is TiO ₂ or TiO _x .

In the above secondary battery, it is preferable that the first n-type oxide semiconductor material is TiO ₂ or TiO _x .

A method for manufacturing a secondary battery according to this embodiment includes a step of forming a first layer on a first electrode, wherein the first layer includes a first n-type oxide semiconductor material; and on the first layer, A step of forming a second layer, wherein the second layer includes a second n-type oxide semiconductor material and a first insulating material; a step of forming a third layer on the second layer; the third layer includes an aluminum compound; A step of forming a fourth layer on the third layer, the fourth layer comprising a p-type oxide semiconductor material; and a step of forming a second electrode on the fourth layer.

In the above-mentioned method for manufacturing a secondary battery, it is preferable to include forming a fifth layer including a second insulating material between the second layer and the third layer, or between the third layer and the fourth layer Steps between formation.

In the above-mentioned method for manufacturing a secondary battery, it is preferable to include a step of forming a fifth layer including a second insulating material between the second layer and the third layer; A step of forming a layer between the aforementioned second layer and the aforementioned fifth layer.

In the above-mentioned method for manufacturing a secondary battery, it is preferable that the third layer and the sixth layer are formed by a sputtering method, coating, or a CVD (chemical vapor deposition) method.
[Inventive effect]

According to the present invention, it is possible to provide a technology for improving the performance of a secondary battery.

An example of an embodiment of the present invention will be described below with reference to the drawings. The following descriptions show suitable embodiments of the present invention, and the technical scope of the present invention is not limited to the following embodiments.

> Embodiment 1 (Laminated Structure of Secondary Battery)>
Hereinafter, the basic configuration of the secondary battery of this embodiment will be described using FIG. 1. FIG. 1 is a cross-sectional view schematically showing a laminated structure of a secondary battery.

In FIG. 1, the secondary battery 100 has a laminated structure obtained by laminating in the following order: a substrate 20, a first electrode 21, a first layer 11, a second layer 12, a third layer 13, a fourth layer 14, And second electrode 22.

[Base material 20]
The base material 20 is an insulating sheet, a substrate, or the like. For example, a resin sheet, a glass substrate, or the like can be used as the base material 20. The substrate 20 may be a semiconductor wafer or the like. Alternatively, the base material 20 may be a conductive substrate or a metal foil. A SUS (Steel Use Stainless) sheet or an aluminum sheet may also be used as the base material 20. For example, the substrate 20 is a sheet having a thickness of 5 μm to 10 μm.
[First electrode 21]
A first electrode 21 is disposed on the substrate 20. The first electrode 21 serves as a negative electrode of the secondary battery 100. As the material of the first electrode 21, a metal material such as tungsten (W), chromium (Cr), or titanium (Ti) can be used. An alloy film containing aluminum (Al), silver (Ag), or the like may be used as the material of the first electrode 21. For example, the first electrode 21 is a film having a thickness of 300 nm.

As a method for forming the first electrode 21, a vapor-phase film formation method such as sputtering, ion plating, electron beam evaporation, vacuum evaporation, or chemical vapor deposition can be mentioned. In addition, a metal electrode can be formed by an electroplating method, an electroless plating method, or the like. Generally, copper, copper alloy, nickel, aluminum, silver, gold, zinc, or tin can be used as the metal used for plating.

When a conductive material is used as the base material 20, the base material 20 can be regarded as the first electrode 21. Thereby, the step of forming the first electrode 21 on the base material 20 can be omitted. When the base material 20 is used as the first electrode 21, a metal foil such as a SUS sheet or an aluminum sheet can be used as the base material 20.

[First floor 11]
A first layer 11 is disposed on the first electrode 21. The first layer 11 is disposed on the second electrode 22 side of the first electrode 21. The first layer 11 is formed in contact with the first electrode 21. The film thickness of the first layer 11 is, for example, about 50 nm to 300 nm.

The first layer 11 includes an n-type oxide semiconductor material (first n-type oxide semiconductor material). The first layer 11 is an n-type oxide semiconductor layer formed with a predetermined thickness. For example, titanium oxide (TiO ₂ ), tin oxide (SnO ₂ ), zinc oxide (ZnO), or the like can be used as the first layer 11. For example, the first layer 11 is an n-type oxide semiconductor layer formed on the first electrode 21 by sputtering or evaporation. As a material of the first layer 11, titanium dioxide (TiO ₂ ) is particularly preferably used.

[2nd floor 12]
A second layer 12 is disposed on the first layer 11, and the second layer 12 has a function as a first charging layer. The second layer 12 is disposed on the second electrode 22 side of the first layer 11. The second layer 12 is formed in contact with the first layer 11. The thickness of the second layer 12 is, for example, 200 nm to 1500 nm.

The second layer 12 contains an insulating material (first insulating material). As the first insulating material, silicone may be used. For example, a silicon compound (polysiloxane) having the following main skeleton is preferably used as the first insulating material: a main skeleton formed of a siloxane bond such as silicon oxide. Accordingly, the second layer 12 contains silicon oxide (SiO _x ) as the first insulating material.

The second layer 12 includes an n-type oxide semiconductor material (second n-type oxide semiconductor material) in addition to the insulating material (first insulating material). That is, the second layer 12 is formed of a mixture of a first insulating material and a second n-type oxide semiconductor material. For example, a fine n-type oxide semiconductor can be used as the second n-type oxide semiconductor material. The second n-type oxide semiconductor is a layer having a charging function by irradiation with ultraviolet rays.

In this case, for example, a second n-type oxide semiconductor material is used as titanium dioxide, and the second layer 12 is formed of silicon oxide and titanium dioxide. In addition, as the n-type oxide semiconductor material that can be used for the second layer 12, tin oxide (SnO ₂ ), zinc oxide (ZnO), and magnesium oxide (MgO) are suitable. A combination of two, three or all of titanium dioxide, tin oxide, zinc oxide, and magnesium oxide may be used.

The second n-type oxide semiconductor material included in the second layer 12 and the first n-type oxide semiconductor material included in the first layer 11 may be the same or different. For example, when the first n-type oxide semiconductor material included in the first layer 11 is titanium oxide, the second n-type oxide semiconductor material of the second layer 12 may be titanium oxide, or may be other than titanium oxide. n-type oxide semiconductor material.

[Third floor 13]
A third layer 13 is arranged on the second layer 12, and the third layer 13 has a function as an ion conductive film. The third layer 13 is disposed on the second electrode 22 side of the second layer 12. The third layer 13 is formed in contact with the second layer 12. The thickness of the third layer 13 is 1 nm to 40 nm.

The third layer 13 is formed of an aluminum compound. The aluminum compound here refers to Al ₂ O ₃ (alumina), AlN (aluminum nitride), AlON (aluminum oxynitride), Al (OH) ₃ (aluminum hydroxide), and SiAlON (silicon-alumina nitride). At least one of. The third layer 13 is formed by, for example, a sputtering method using the aluminum compound as a target.

For example, an aluminum oxide layer formed by a sputtering method or the like becomes the third layer 13. As a film formation method, reactive sputtering can be used: reactive sputtering using pure Al as a target or an Al alloy containing Al as a main component as a target. Alternatively, an Al-Si alloy in which Si is added to Al can be used as the Al alloy. In this case, the third layer 13 contains Si. That is, the third layer 13 is an alumina layer containing Si.

Alternatively, the aluminum oxide layer can be formed by an ALD (Atomic Layer Deposition) method, a CVD method, a coating method, or the like.

[Fourth floor 14]
A fourth layer 14 is disposed on the third layer 13. The fourth layer 14 is disposed on the second electrode 22 side of the third layer 13. The fourth layer 14 is formed in contact with the third layer 13. The fourth layer 14 can be formed in a thickness ranging from 200 nm to 1500 nm.

The fourth layer 14 includes a p-type oxide semiconductor material. The fourth layer 14 is a p-type oxide semiconductor layer formed in a predetermined thickness. As the p-type semiconductor material constituting the fourth layer 14, nickel oxide (NiO), copper aluminum oxide (CuAlO ₂ ), or the like can be used. The fourth layer 14 is a nickel oxide layer having a thickness of 400 nm. For example, a nickel oxide layer formed by a sputtering method or the like becomes the fourth layer 14.

[Second electrode 22]
A second electrode 22 is disposed on the fourth layer 14. The second electrode 22 is formed in contact with the fourth layer 14. The second electrode 22 may be formed by a conductive film. A metal material such as chromium (Cr) or copper (Cu) can be used as the material of the second electrode 22. Other metal materials include a silver (Ag) alloy containing aluminum (Al) and the like. Examples of the formation method include a vapor-phase film formation method such as sputtering, ion plating, electron beam evaporation, vacuum evaporation, and chemical vapor deposition. In addition, a metal electrode can be formed by an electrolytic plating method, an electroless plating method, or the like. Generally, copper, copper alloy, nickel, aluminum, silver, gold, zinc, or tin can be used as the metal used for plating. For example, the second electrode 22 is an Al film having a thickness of 300 nm.

As such, the third layer 13 including an aluminum compound layer such as alumina is located between the second layer 12 and the fourth layer 14. According to this configuration, the performance of the secondary battery 100 can be improved. By providing a third layer 13 containing an aluminum compound layer such as alumina, the interface between the second layer 12 and the fourth layer 14 (specifically, the interface between the second layer 12 and the third layer 13 and the first (The interface between the three layers 13 and the fourth layer 14) to reduce the leakage current and reduce the self-discharge level. Further, by setting the thickness of the third layer 13 to 1 nm to 40 nm, the leakage current can be further reduced.

The thickness of the aluminum compound layer (here, the aluminum oxide layer) is preferably set to 1 to 40 nm. This makes it possible to suppress an increase in internal resistance and to suppress self-discharge. For example, if the alumina layer is made too thick, the internal resistance becomes high, and the voltage drop becomes large when the discharge current is made large. If the alumina layer is made too thin, although the internal resistance can be reduced, the self-discharge tends to increase. Therefore, it is preferable to set the thickness of the alumina layer to 1 nm to 40 nm.

Figure 2 shows the charge and discharge characteristics of two samples I and II. In FIG. 2, the horizontal axis system represents time, and the vertical axis system represents voltage. The third layer 13 in Sample I is an aluminum oxide film with a thickness of about 20 nm, and the third layer 13 in Sample II is an aluminum oxide film with a thickness of about 40 nm. FIG. 2 shows the time variation of voltage when samples I and II are charged and discharged under the same charge and discharge conditions.

The sputtering film formation conditions of the third layer 13 in the sample I were DC power (Direct Current power) of 1 kW, film formation time of 30 minutes, argon flow rate of 10 SCCM, and oxygen flow rate of 3 SCCM. The sputtering film formation conditions of the third layer 13 in the sample II were 1 kW DC power, film formation time 30 minutes, argon flow rate 100 SCCM, and oxygen flow rate 5 SCCM.

Comparative Example of Sample I is compared to the following: The third layer 13 is set to a comparative example silicon oxide (SiO _x) of the insulating film. In the case of Sample I, although the discharge time was approximately the same as that of the comparative example, the leakage was increased. On the other hand, in the case of Sample II, compared with the comparative example, the leakage current is small but the internal resistance is large, and the output density is decreased but the energy density is increased.

(Production method)
Next, a method for manufacturing the secondary battery 100 according to this embodiment will be described using FIG. 3. FIG. 3 is a flowchart showing a method of manufacturing the secondary battery 100.

A first electrode 21 is formed on the substrate 20 (S10). The first electrode 21 is formed by, for example, a sputtering method. The first electrode 21 is, for example, a tungsten electrode or a titanium electrode.

A first layer 11 is formed on the first electrode 21 (S11). The first layer 11 includes the first n-type oxide semiconductor material as described above. For example, for the first layer 11, a TiO ₂ film can be formed as the first layer 11 by a sputtering method using Ti or TiO as a target. The first layer 11 may be provided as a TiO ₂ film having a thickness of 50 nm to 200 nm.

Next, a second layer 12 is formed on the first layer 11 (S12). The second layer 12 can be formed using a coating thermal decomposition method. First, a coating solution prepared by mixing a solvent with a mixture of a precursor of the following substance and silicone oil: titanium oxide, tin oxide, or zinc oxide is prepared. Here, with the second layer 12, an example in which silicon oxide as the first insulating material is made into titanium oxide as the second n-type oxide insulating material will be described. In this case, titanium fatty acid, which is a precursor of titanium oxide, can be used. The coating liquid was prepared by stirring the fatty acid titanium together with the silicone oil and the solvent.

The coating liquid is applied to the first layer 11 by a spin coating method, a slit coating method, or the like. Specifically, the coating liquid is applied by a spin coating device at a rotation speed of 500 rpm to 3000 rpm.

Next, the coating film is dried, calcined, and UV (ultraviolet; ultraviolet) irradiated, whereby the second layer 12 can be formed on the first layer 11. For example, after coating, it is dried on a hot plate. The drying temperature on the hot plate is about 30 ° C to 200 ° C, and the drying time is about 5 minutes to 30 minutes. After drying, it was calcined in the atmosphere using a calcining furnace. The calcination temperature is, for example, about 300 ° C to 600 ° C, and the calcination time is about 10 minutes to 60 minutes.

As a result, the fatty acid salt is decomposed to form a layer in which polysiloxane fine particles and titanium dioxide fine particles are mixed. The calcined coating film was irradiated with UV light by a low-pressure mercury lamp. UV irradiation time is 10 minutes to 60 minutes.

When the second n-type oxide semiconductor is titanium oxide, for example, titanium stearate can be used as another example of the precursor. Titanium oxide, tin oxide, and zinc oxide are formed by decomposition of an aliphatic acid salt that is a precursor of a metal oxide. Regarding titanium oxide, tin oxide, zinc oxide, and the like, fine particles of an oxide semiconductor may be used without using a precursor. Nanoparticles of titanium oxide or zinc oxide are mixed with silicone oil, thereby producing a mixed liquid. Further, a solvent is mixed with the mixed liquid to produce a coating liquid.

A third layer 13 is formed on the second layer 12 (S13). The third layer is an aluminum compound film such as an alumina film. An aluminum oxide film can be formed by reactive sputtering using pure Al or an Al alloy as a target. The third layer 13 is formed here by reactive sputtering using an Al-Si alloy as a target. Here, an Al-Si alloy with 1.0 at% Si added was used. DC power is 0.5 kW, film formation time is 10 minutes, argon flow rate is 100 SCCM, and oxygen flow rate is 5 SCCM.

Next, a fourth layer 14 is formed on the third layer 13 (S14). The fourth layer 14 is a nickel oxide (NiO) layer. The fourth layer 14 is formed on the third layer 13 by a sputtering method using Ni or NiO as a target.

A second electrode 22 is formed on the fourth layer 14 (S15). Examples of the method for forming the second electrode 22 include a vapor-phase film-forming method such as sputtering, ion plating, electron beam evaporation, vacuum evaporation, and chemical vapor deposition. Alternatively, a mask may be used to partially form the second electrode 22. The second electrode 22 can be formed by an electrolytic plating method, an electroless plating method, or the like. Generally, copper, copper alloy, nickel, aluminum, silver, gold, zinc, or tin can be used as the metal used for plating. For example, the second electrode 22 is an Al film having a thickness of 300 nm.

According to the manufacturing method described above, a high-performance secondary battery 100 can be manufactured. In particular, the secondary battery 100 having a small leakage current can be manufactured. By setting the thickness of the third layer 13 to 1 nm to 40 nm, the leakage current can be further reduced.

> Implementation Mode 2>
A secondary battery 100A according to the second embodiment will be described with reference to FIG. 4. FIG. 4 is a cross-sectional view showing a laminated structure of a secondary battery 100A. In FIG. 4, the secondary battery 100A has a laminated structure in which the substrate 20, the first electrode 21, the first layer 11, the second layer 12, the third layer 13, the fifth layer 15, The fourth layer 14 and the second electrode 22.

A fifth layer 15 is disposed on the second electrode 22 side of the third layer 13. A fourth layer 14 is disposed on the second electrode side of the fifth layer 15. That is, the fifth layer 15 is disposed between the third layer 13 and the fourth layer 14. The fifth layer 15 is formed in contact with the third layer 13. The fourth layer 14 is formed in contact with the fifth layer 15.

The thickness of the fifth layer 15 is 100 nm to 150 nm. The fifth layer 15 can be formed in a thickness ranging from 50 nm to 250 nm. More preferably, the fifth layer 15 can also be formed in a thickness ranging from 150 nm to 200 nm.

The fifth layer 15 has at least one of water (H ₂ O) and a hydroxyl group (-OH), and has a function as a solid electrolyte layer that moves H ⁺ . The fifth layer 15 is a layer containing an insulating material (second insulating material). The fifth layer 15 contains silicon oxide (SiO _x ) as a second insulating material.

The fifth layer 15 may include, for example, silicon oxide (second insulating material) to which the following hydratable metal oxides are added: water oxide ions such as tantalum oxide, tungsten oxide, tin oxide, phosphorus oxide, and aluminum oxide ( OH ^-) and Xiang hydrated metal oxide in (hydronium) ion (H ₃ O ⁺⁾ at least one movable. As the hydrated oxide, any one of tin (II) oxide, tantalum oxide, zirconia, and alumina may be used. Further, the fifth layer 15 may have phosphorus or phosphorus oxide.

In the fifth layer 15, a conductivity adjusting material may be added to the second insulating material. The conductivity adjusting material may include an n-type oxide semiconductor material (third n-type oxide semiconductor material) or an oxide of a metal. For example, as the conductivity adjusting material, the fifth layer 15 may include at least one selected from the group consisting of oxides of Ti, Sn, Zn, Nb, or Mg. By setting the conductivity-adjusting material to an oxide of Sn, Zn, Ti, Nb, or Mg, the fifth layer 15 can be formed thickly and electrically withstand voltage.

Specifically, tin oxide (SnO _x ) can be used as the third n-type oxide semiconductor material included in the fifth layer 15. In this case, the fifth layer 15 contains a mixture of silicon oxide and tin oxide. In the fifth layer 15, a third n-type oxide semiconductor material is added to silicon oxide, silicon nitride or polysiloxane. The n-type oxide semiconductor is dispersed in silicon dioxide as a second insulating material.

The third n-type oxide semiconductor material system in the fifth layer 15 may include more than one selected from tin oxide (SnO _x ), zinc oxide (ZnO), titanium oxide (TiO _x ), and niobium oxide (NbO _x ). Oxide.

The second n-type oxide semiconductor material included in the second layer 12 and the third n-type oxide semiconductor material included in the fifth layer 15 may be the same material or different materials. For example, when the third n-type oxide semiconductor material in the fifth layer 15 is tin oxide, the second n-type oxide semiconductor material in the second layer 12 may be tin oxide or an n-type other than tin oxide. Oxide semiconductor material.

Next, a manufacturing method is demonstrated. Since the method of forming the layers other than the fifth layer 15 is the same as that of the first embodiment, the description is omitted. That is, the step of forming the fifth layer 15 shown below is performed between S13 and S14 of FIG. 3.

The fifth layer 15 can be manufactured by the same method as the third layer 13. Specifically, a fatty acid tin is stirred with a polysiloxane and a solvent to prepare a chemical solution. This chemical solution is applied onto the second layer 12 using a spin coating device. The rotation speed is, for example, about 500 rpm to 3000 rpm. After coating, it was dried on a hot plate. The drying temperature on the hot plate is, for example, about 30 ° C to 200 ° C, and the drying time is, for example, about 5 minutes to 30 minutes.

Furthermore, post-drying calcination is performed. In the post-drying calcination, the calcination is performed in the atmosphere using a calcining furnace. The calcination temperature is, for example, about 300 ° C to 600 ° C, and the calcination time is, for example, about 10 minutes to 60 minutes. After the calcination, UV irradiation by a low-pressure mercury lamp was performed. The UV irradiation time is, for example, about 10 minutes to 100 minutes. The film thickness of the fifth layer 15 after UV irradiation is, for example, about 100 nm to 300 nm.

In the case of tin oxide, fine particles of an oxide semiconductor may be used without using a precursor. The mixed liquid is produced by mixing nano particles of tin oxide with silicone oil. Furthermore, a coating liquid is produced by mixing a mixed liquid and a solvent.

Another example of the formation steps of the fifth layer 15 will be described. Here, as the fifth layer 15, a layer composed of only a second insulating material is used. That is, a method of forming the fifth layer 15 not containing the third n-type oxide semiconductor material is described below.

The silicone fluid is stirred with a solvent to prepare a chemical solution. A spin coating device is used to apply the chemical solution to the second layer 12. A spin coater is used here. The rotation speed of the spin coating device is, for example, about 500 rpm to 3000 rpm. After coating, it was dried on a hot plate. The drying temperature on the hot plate is, for example, about 50 ° C to 200 ° C, and the drying time is, for example, about 5 minutes to 30 minutes.

Furthermore, post-drying calcination is performed. In the post-drying calcination, the calcination is performed in the atmosphere using a calcining furnace. The calcination temperature is, for example, about 300 ° C to 600 ° C, and the calcination time is, for example, about 10 minutes to 60 minutes. After the calcination, UV irradiation by a low-pressure mercury lamp was performed. The UV irradiation time is, for example, about 10 minutes to 60 minutes. The film thickness of the fifth layer 15 after UV irradiation is, for example, about 10 to 100 nm.

In this configuration, a third layer 13 as an alumina layer, a fifth layer 15 as a solid electrolyte layer, and a fourth layer 14 are disposed on the second layer 12. According to this configuration, the performance of the secondary battery 100A can be improved. By setting the third layer 13 as an alumina layer, the interface between the second layer 12 and the fifth layer 15 (specifically, the interface between the second layer 12 and the third layer 13 and the third layer 13) Interface with the fifth layer 15) to reduce leakage current and reduce self-discharge potential.

As in the first embodiment, it is more preferable to set the film thickness of the third layer 13 to 1 nm to 40 nm. Thereby, a more favorable charge-discharge characteristic can be obtained. In the second embodiment, the sputtering film forming conditions for the third layer 13 are DC power of 0.5 kW, film forming time of 10 minutes, argon flow rate of 100 SCCM, and oxygen flow rate of 5 SCCM. The film thickness of the third layer 13 under the film formation conditions was 5 nm.

> Modification 1>
The secondary battery 100B according to the first modification will be described using FIG. 5. FIG. 5 is a cross-sectional view showing a laminated structure of the secondary battery 100B. The secondary battery 100B has a laminated structure in which the substrate 20, the first electrode 21, the first layer 11, the second layer 12, the fifth layer 15, the third layer 13, the fourth layer 14 and Second electrode 22.

Therefore, the fifth layer 15 is disposed on the second electrode 22 side of the second layer 12. A third layer 13 is disposed on the second electrode 22 side of the fifth layer 15. That is, the fifth layer 15 is disposed between the third layer 13 and the second layer 12. The fifth layer 15 is formed in contact with the third layer 13. The fifth layer 15 is formed in contact with the second layer 12.
Therefore, the configuration of the fifth layer 15 and the third layer 13 is interchanged with respect to the configuration of FIG. 4. In other words, compared to the case where the fifth layer 15 is disposed between the third layer 13 and the fourth layer 14 in the configuration of FIG. 4, in the first modification, the fifth layer 15 is disposed between the third layer 13 and the first layer 15. The situation between the two floors 12. In addition, since the order of lamination of the fifth layer 15 is the same as that of the first embodiment, description thereof is appropriately omitted.

The fifth layer 15 is a layer containing silicon oxide (SiO _x ) similarly to the fifth layer 15 of the second embodiment. Specifically, the fifth layer 15 is a layer containing silicon oxide (SiO _x ) as a third insulating material as a main component. For example, the fifth layer 15 can be formed by applying a silicone oil on the second layer 12. That is, the step of forming the fifth layer 15 may be performed between S12 and S13 in FIG. 3. Since the formation steps of the fifth layer 15 are the same as those of the fifth layer 15 of the second embodiment, detailed description is omitted.

In this configuration, a fifth layer 15 as a solid electrolyte layer, a third layer 13 as an aluminum compound layer, and the like, and a fourth layer 14 are disposed on the second layer 12. According to this configuration, the performance of the secondary battery 100B can be improved. By providing the third layer 13 as an aluminum compound layer such as an alumina layer, the interface between the fifth layer 15 and the fourth layer (specifically, the interface between the fifth layer 15 and the third layer 13 and the first layer) can be controlled. Interface between the three layers 13 and the fourth layer 14) to reduce leakage current and reduce self-discharge potential.

As in the first embodiment, it is more preferable to set the film thickness of the third layer 13 to 1 nm to 40 nm. Thereby, a more favorable charge-discharge characteristic can be obtained.

> Modification 2
The secondary battery 100C according to the second modification will be described using FIG. 6. FIG. 5 is a cross-sectional view showing a laminated structure of a secondary battery 100C. The secondary battery 100C has a laminated structure which is laminated in the following order: the substrate 20, the first electrode 21, the first layer 11, the second layer 12, the third layer 13, the fifth layer 15, the sixth layer 16, The fourth layer 14 and the second electrode 22.

Therefore, compared with the multilayer structure shown in FIG. 4, a multilayer structure in which a sixth layer 16 is added is obtained. A sixth layer 16 is disposed on the second electrode 22 side of the fifth layer 15. A fourth layer 14 is disposed on the second electrode 22 side of the sixth layer 16. That is, the sixth layer 16 is disposed between the fifth layer 15 and the fourth layer 14. The sixth layer 16 is formed in contact with the fifth layer 15. The fourth layer 14 is formed in contact with the sixth layer 16.

The sixth layer 16 is formed of an aluminum compound similarly to the third layer 13. The so-called aluminum compound means Al ₂ O ₃ (alumina), AlN (aluminum nitride), AlON (aluminum oxynitride), Al (OH) ₃ (aluminum hydroxide), and SiAlON (silicon-alumina nitride) ) At least one of them. The sixth layer 16 is formed by, for example, a sputtering method using these aluminum compounds as targets. Therefore, two aluminum compound layers are formed between the second layer 12 and the fourth layer 14. A fifth layer 15 is arranged between the two aluminum compound layers. The film thickness and formation method of the sixth layer 16 can be set to be the same as those of the third layer 13. In this embodiment, the sixth layer 16 and the third layer 13 are aluminum oxide layers.

In this configuration, a third layer 13 (alumina layer), a fifth layer 15 as a solid electrolyte layer, a sixth layer 16 (alumina layer), and a fourth layer 14 are disposed on the second layer 12. According to this configuration, the performance of the secondary battery 100C can be improved. By providing the third layer 13 as an aluminum compound layer such as an alumina layer, it is possible to control the interface between the second layer 12 and the fifth layer 15 (specifically, the interface between the second layer 12 and the third layer 13, And the third layer 13 and the fifth layer 15) to reduce leakage current. Furthermore, by providing the sixth layer 16 as an aluminum compound layer such as an aluminum layer, the interface between the fifth layer 15 and the fourth layer 14 (specifically, the interface between the fifth layer 15 and the sixth layer 16 can be controlled. And the sixth layer 16 and the fourth layer 14) to reduce leakage current. By reducing these leakage currents, the self-discharge potential can be reduced.

As in the first embodiment, it is more preferable to set the film thickness of the third layer 13 to 1 nm to 40 nm. Further, the total film thickness of the third layer 13 and the sixth layer 16 may be set to 1 nm to 40 nm. Thereby, a more favorable charge-discharge characteristic can be obtained. The third layer 13 may be thicker than the sixth layer 16. Alternatively, the third layer 13 may be thinner than the sixth layer 16. The third layer 13 may be the same thickness as the sixth layer 16.

(Charge and discharge test)
Hereinafter, the measurement results after self-discharge of the samples of the laminated structure shown in FIGS. 4 to 6 will be described. The sample of the multilayer structure shown in FIG. 4 is taken as sample A, the sample of the multilayer structure shown in FIG. 5 is taken as sample B, and the sample of the multilayer structure shown in FIG. Further, the sample composed of the layers shown in FIG. 7 is regarded as the sample D. The third layer 13 and the sixth layer 16 are not formed in the sample D. That is, in the sample D, a stacked layer structure in which only the fifth layer 15 is arranged between the second layer 12 and the fourth layer 14.

In samples A to C, the sputtering film formation conditions of the alumina layer were DC power of 0.5 kW, film formation time of 10 minutes, argon flow rate of 100 SCCM, and oxygen flow rate of 5 SCCM. The film thickness of the third layer 13 under the film formation conditions is 5 nm.

Here, after the samples A to D are charged under the same charging conditions, the remaining power and the sustaining voltage when the samples are left for a predetermined time are measured. The measurement results are shown in Table 1. In addition, the remaining power is expressed as a ratio of the power to the charged power after self-discharge. Here, the remaining power and the sustaining voltage are normalized so that the value of the sample D becomes 1.
[Table 1]

When the remaining power of the sample D after self-discharge is set to 1, the remaining power of the sample A is 0.76, the remaining power of the sample B is 1.2, and the remaining power of the sample C is 1.32. Therefore, compared with sample D, the self-discharge ratio is increased by 22% in sample B, and the self-discharge ratio is increased by 32% in sample C.

When the sustain voltage of the sample D after self-discharge is set to 1, the sustain voltage of the sample A is 0.94, the sustain voltage of the sample B is 0.99, and the sustain voltage of the sample C is 0.99. Therefore, the cases where the voltage decreases in samples B and C become smaller.

In this manner, by disposing the third layer 13 between the second layer 12 and the fourth layer 14, the performance of the secondary battery can be improved.

Although an example of the embodiment of the present invention has been described above, the present invention includes appropriate modifications that do not impair the object and advantages of the present invention, and is not limited to the above-mentioned embodiment.

This application claims priority based on Japanese application Japanese Patent Application No. 2018-52028, which has been filed on March 20, 2018, and the entire disclosure thereof is incorporated herein.

11‧‧‧First layer (n-type oxide semiconductor layer)

12‧‧‧Second layer (SiOx + TiOx)

13‧‧‧ third layer (aluminum compound layer)

14‧‧‧ fourth layer (p-type oxide semiconductor layer)

15‧‧‧ fifth floor

16‧‧‧ sixth layer (aluminum compound layer)

20‧‧‧ substrate

21‧‧‧first electrode

22‧‧‧Second electrode

100, 100A, 100B, 100C, 100D‧‧‧ secondary batteries

FIG. 1 is a view schematically showing a laminated structure of a secondary battery according to the first embodiment.

FIG. 2 is a graph showing the discharge characteristics of the secondary battery according to the first embodiment.

Fig. 3 is a flow chart showing a method for manufacturing a secondary battery according to the first embodiment.

FIG. 4 is a view schematically showing a laminated structure of a secondary battery according to a second embodiment.

FIG. 5 is a view schematically showing a laminated structure of a secondary battery according to a first modification.

FIG. 6 is a view schematically showing a laminated structure of a secondary battery according to a second modification.

FIG. 7 is a view schematically showing a laminated structure of a secondary battery of a comparative example.

Claims (16)

A secondary battery comprising: First electrode Second electrode The first layer is disposed between the first electrode and the second electrode, and includes a first n-type oxide semiconductor material; The second layer is disposed on the first layer and includes a second n-type oxide semiconductor material and a first insulating material; The third layer is disposed on the second layer and contains an aluminum compound; and The fourth layer is disposed on the third layer and includes a p-type oxide semiconductor material. The secondary battery according to claim 1, wherein the fifth layer including the second insulating material is disposed between the second layer and the third layer, or is disposed between the third layer and the fourth layer between. The secondary battery according to claim 1, wherein the fifth layer including the second insulating material is disposed between the second layer and the third layer; The sixth layer including the aluminum compound is disposed between the second layer and the fifth layer. The secondary battery according to claim 1 or 2, wherein the aluminum compound contains at least one of Al ₂ O ₃ , AlN, AlON, Al (OH) _3, and SiAlON. The secondary battery according to claim 1 or 2, wherein the thickness of the third layer is 1 nm to 40 nm. The secondary battery according to claim 3, wherein the thickness of the sixth layer is 1 nm to 40 nm. The requested item 2 or 3, according to the secondary battery, wherein the fifth layer is based as the second insulating material layer is SiO _x as the main component; a fifth layer based on the metal oxide is added. The secondary battery according to claim 7, wherein the metal oxide is SnO _x . The secondary battery according to claim 1 or 2, wherein the third layer contains Si. The secondary battery according to claim 3 or 6, wherein the sixth layer contains Si. The requested item described in the secondary battery 1 or 2, wherein the first insulating material is SiO _x; the second n-type oxide semiconductor material is TiO ₂ or TiO _x. The secondary battery according to claim 1 or 2, wherein the first n-type oxide semiconductor material is TiO ₂ or TiO _x . A method for manufacturing a secondary battery, comprising: A step of forming a first layer on the first electrode, the aforementioned first layer system comprises a first n-type oxide semiconductor material; A step of forming a second layer on the aforementioned first layer, the aforementioned second layer system comprises a second n-type oxide semiconductor material and a first insulating material; A step of forming a third layer on the aforementioned second layer, the aforementioned third layer comprises an aluminum compound; A step of forming a fourth layer on the third layer, the fourth layer including a p-type oxide semiconductor material; and A step of forming a second electrode on the aforementioned fourth layer. The method for manufacturing a secondary battery according to claim 13, further comprising forming a fifth layer including a second insulating material between the second layer and the third layer, or between the third layer and the fourth layer Steps between layers. The method for manufacturing a secondary battery according to claim 13, comprising: A step of forming a fifth layer including a second insulating material between the aforementioned second layer and the aforementioned third layer; and A step of forming a sixth layer containing an aluminum compound between the aforementioned second layer and the aforementioned fifth layer. The method for manufacturing a secondary battery according to claim 15, wherein the third layer and the sixth layer are formed by a sputtering method, a coating method, or a chemical vapor deposition method.