JP2014154505A - Thin film solid secondary battery element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film solid secondary battery element excellent also in productivity and improved in charge/discharge characteristics.SOLUTION: In a thin film solid secondary battery element, a first electrode 1, an electron transport layer 5, a charging layer 3, an electron block layer 4 and a second electrode 2 are stacked, in the order, on a substrate 10. The charging layer 3 contains an inorganic material, the electron transport layer 5 is formed of an inorganic oxide material, and the inorganic oxide material contains a niobium oxide or a tungsten oxide.

Description

  The present invention relates to a thin film solid secondary battery element.

  2. Description of the Related Art In recent years, research on reducing the thickness and weight of a secondary battery as a power source and increasing its capacity has been actively conducted in view of an increase in power consumption accompanying the improvement in performance of mobile terminals.

  Secondary batteries include secondary batteries that store energy as electrochemical energy using an oxidation-reduction reaction, electrochemical capacitors, and capacitors that can be stored as a change in capacity of an electric double layer. Secondary batteries include water-based secondary batteries such as acid / lead batteries, nickel / cadmium batteries, alkaline batteries, nickel metal hydride secondary batteries, and lithium ion secondary batteries that use active materials that are effective for ion insertion reactions. Non-aqueous secondary batteries are known.

Lithium ion secondary batteries are widely used mainly in electronic devices such as portable devices. This is because the lithium ion secondary battery has a higher voltage, a large charge / discharge capacity, and less harmful effects due to the memory effect than a nickel-cadmium secondary battery.
Incidentally, electronic devices are being further reduced in size and weight, and lithium ion secondary batteries that are further reduced in size and weight are required to be mounted on these electronic devices. A conventional lithium ion secondary battery has a structure in which a metal piece or a metal foil is used for both the positive electrode and the negative electrode, which is immersed in an electrolytic solution between both electrodes and covered with a container. Therefore, there is a limit to thinning and miniaturization.

  However, recently, in order to enable further reduction in thickness and size, a polymer battery using a gel electrolyte instead of an electrolytic solution and a thin film solid secondary battery using a solid electrolyte have been developed. The polymer batteries described in Patent Document 1 (Patent No. 3561580) and Patent Document 2 (Patent No. 2934450) are thinner and smaller than a general lithium ion secondary battery using an electrolytic solution. Although it is possible, a gel electrolyte, a sealing material, and the like are required, so the thickness is about 0.1 mm.

On the other hand, a thin-film solid secondary battery has a configuration in which a current collector thin film, a negative electrode active material thin film, a solid electrolyte thin film, a positive electrode active material thin film, and a current collector thin film are sequentially stacked on a substrate, or a structure by reverse stacking as described above. doing. Thereby, a thin film solid secondary battery can be made very thin compared with a lithium ion secondary battery.
Of these, graphite carbon, which is standardly used as a negative electrode active material, is extremely difficult to form a thin film. Even if a thin film can be formed, only a thin film with high resistance and poor adhesion can be obtained. Therefore, it is difficult to use as a negative electrode of a thin-film solid secondary battery.
In addition, as a negative electrode material that has recently been examined as an alternative material for graphite carbon, silicon, tin, or their alloy materials are accompanied by volume expansion / contraction during lithium ion insertion and removal, and charge and discharge in thin film solid state secondary batteries. By repeating the above, film peeling tends to occur. Although it is conceivable to use metallic lithium as the negative electrode material as it is, metallic lithium is difficult to handle because it is vulnerable to moisture and oxygen and is easily oxidized.

  Accordingly, metal oxides such as vanadium oxide and niobium oxide are often used as the negative electrode of the thin-film solid secondary battery, which has little volume expansion / contraction during insertion and withdrawal of lithium ions. Patent Document 3 (Japanese Patent No. 3116857) and Patent Document 4 (Japanese Patent No. 3531866) report thin-film solid secondary batteries using vanadium oxide or niobium oxide as a negative electrode. However, vanadium oxide is weak against moisture and oxygen, is not only easily oxidized, but also has toxicity, so that it is difficult to handle it during the manufacturing process or use.

  Patent Document 5 (Japanese Patent Application Laid-Open No. 2004-179158) uses lithium titanate or the like as an oxide other than silicon or vanadium oxide in the negative electrode layer. This lithium titanate is known not to be distorted in insertion and release of Li ions, and is suitable as a negative electrode material for a thin film solid secondary battery. However, lithium titanate has a slightly smaller charge / discharge capacity compared to niobium oxide, vanadium oxide, etc., and lithium titanate is an insulator, so its electronic conductivity is low and its ionic conductivity is low. There is a problem that the internal resistance is increased and the high-speed charge / discharge characteristics are inferior. Furthermore, when a thin film is formed by a vacuum process such as sputtering, the lithium titanate sintered body has low electrical conductivity and poor thermal conductivity, so not only the sputtering rate is slow, but also the target is easy to break, so a strong power is applied. There is a drawback that the film formation rate becomes extremely slow.

  Secondary batteries that do not involve electrochemical reaction or ion conduction include electric double layer capacitors. However, although these capacitors are excellent in the ability to charge and discharge high-density power in a short time, the energy density is inferior to that of a lithium ion secondary battery.

  On the other hand, as a new secondary battery, an oxide semiconductor formed on a conductor is irradiated with light, and an electron trap is formed in the oxide semiconductor accompanying a photoexcitation structure change, to a semiconductor secondary battery (quantum battery). The technology to be applied is being developed by Hiroshima University Hiroshi Kashiyama, Guera Technology and others. ((Non-patent document 1 (Hiroshi Hiroyama, “Research and development of semiconductor secondary battery”, Hiroshima University new technology briefing 2010 material), Non-patent document 2 (Guela Technology website (http: //www.guala-tec. co.jp/technology/index.html)))

According to this technique, it can be expected to be applied as an electrochromic element that causes coloring of the charging layer with charging, and a manufacturing method thereof is disclosed in Patent Document 6 (WO2008 / 053561). The characteristics of the semiconductor secondary battery are that it is all solid and can be easily thinned, has high energy density, and has high safety and environmental resistance.
In the above, an oxide semiconductor layer is sandwiched between electrodes, and a secondary battery is formed by the function of the oxide semiconductor layer subjected to the photoexcitation structure change. At this time, nickel oxide is inserted as an electron blocking layer between the electrode and the oxide semiconductor layer, and this nickel oxide prevents unnecessary electron injection into the electrode and causes a reversible state change. Therefore, this nickel oxide plays a very important role.

  Nickel oxide is usually formed by sputtering. However, nickel oxide is a non-stoichiometric compound, and the reproducibility of film formation is never high, and there is a concern about film quality variation between batches. Furthermore, it is necessary to control the conditions severely in the sputter film formation, and even if controlled, there will be a considerable variation in film quality within the surface. In particular, in the case of large-area film formation, the influence appears remarkably. In addition, the quality of the nickel oxide can be improved by annealing, but the charge layer is also annealed during the annealing process, causing deterioration of the photoexcitation structure change of the charge layer, resulting in charge / discharge characteristics. It will decline.

  The present invention has been made in view of the above problems in the prior art, and an object of the present invention is to provide a thin-film solid secondary battery element having excellent productivity and improved charge / discharge characteristics.

  A thin-film solid secondary battery element according to the present invention for solving the above-mentioned problems is obtained by laminating a first electrode, an electron transport layer, a charge layer, an electron block layer, and a second electrode in this order on a substrate, The layer includes an inorganic material, and the electron transport layer includes an inorganic oxide material, and the inorganic material oxide includes niobium oxide or tungsten oxide.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in productivity and can provide the thin film solid secondary battery element which improved the charging / discharging characteristic.

(A) It is the schematic which shows the structure in 1st Embodiment of the thin film solid secondary battery element which concerns on this invention. (B) It is the schematic which shows the structure in 2nd Embodiment of the thin film solid secondary battery element which concerns on this invention. (C) It is the schematic which shows the structure in 3rd Embodiment of the thin film solid secondary battery element which concerns on this invention. It is an upper surface schematic diagram showing the composition of the thin film solid secondary battery element concerning the present invention. It is a graph which shows the relationship between the mixing ratio of tungsten and titanium and current capacity efficiency. It is a graph which shows the relationship between the mixing ratio of tungsten niobium and current capacity efficiency. It is a graph which shows the relationship between the mixing ratio of tungsten, niobium and titanium and current capacity efficiency.

The thin-film solid secondary battery element according to the present invention includes a substrate on which a first electrode, an electron transport layer, a charge layer, an electron block layer, and a second electrode are laminated in this order, and the charge layer includes an inorganic material. The electron transport layer is made of an inorganic oxide material, and the inorganic material oxide contains niobium oxide or tungsten oxide.
The thin-film solid secondary battery element according to the present invention is characterized in that a first electrode, an electron block layer, a charge layer, an electron transport layer, and a second electrode are laminated in this order on a substrate.
Furthermore, in the thin film solid secondary battery element according to the present invention, a first electrode, a charging layer, an electron block layer, and a second electrode are laminated in this order on a substrate, and the charging layer includes an inorganic material, The electron blocking layer contains an organic material and has at least one organic-inorganic interface.
Next, the thin film solid secondary battery element according to the present invention will be described in more detail.

FIG. 1A to FIG. 1C are schematic views showing configurations in the first to third embodiments of the thin-film solid secondary battery element according to the present invention.
(First embodiment)
As shown in FIG. 1A, the configuration of the thin film solid secondary battery element according to the present invention in the first embodiment includes a first electrode 1, an electron transport layer 5, a charge layer 3, an electron on a substrate 10. The block layer 4 and the second electrode 2 are formed in this order, and the charging layer 3 is sandwiched between the electrodes via the electron block layer 4 and the electron transport layer 5.
(Second Embodiment)
In the second embodiment of the thin-film solid secondary battery element according to the present invention, as shown in FIG. 1 (b), a first electrode 1, an electronic block layer 4, a charging layer 3 and an electron are formed on a substrate 10. The transport layer 5 and the second electrode 2 are formed in this order, and the charge layer 3 is sandwiched between the electrodes via the electron block layer 4 and the electron transport layer 5.
(Third embodiment)
As shown in FIG. 1 (c), the configuration of the thin film solid secondary battery element according to the present invention in the third embodiment includes a first electrode 1, a charge layer 3, an electronic block layer 4, The two electrodes 2 are formed in this order, and the charging layer 3 is sandwiched between the electrodes.

Hereinafter, each constituent material and formation process of the element in the first to third embodiments will be described.
Although the embodiments described below are preferred embodiments of the present invention, various technically preferable limitations are attached thereto, but the scope of the present invention is intended to limit the present invention in the following description. Unless otherwise described, the present invention is not limited to these embodiments.

<Substrate 1>
The substrate 10 used in the present invention is made of a material such as glass, thin film metal, or plastic, and for example, alkali-free glass, borosilicate glass, float glass, soda lime glass, polymer resin, or the like can be used. However, when using a substrate having low heat resistance, it is necessary to set the process temperature below that temperature. When using a metal substrate, it is necessary to form an insulating layer. In addition, by using a flexible substrate, a thin film solid secondary battery having flexibility can be manufactured.

<First electrode 1>
The first electrode 1 used in the present invention is not particularly limited as long as it is a conductive substance, and known metals, metal oxides, and organic conductive materials can be used.
For example, indium tin oxide (referred to as ITO), fluorine doped tin oxide (referred to as FTO), antimony doped tin oxide (referred to as ATO), indium / zinc oxide, niobium / titanium oxide, carbon nanotube, graphene, etc. , Al, Ag, Au, Pt, Ti, Cr, and the like, and these may be used alone or in combination.

  Although there is no restriction | limiting in the thickness of the 1st electrode 1, the thing with a low specific resistance is preferable from the point of energy density. The film thickness is preferably 5 nm to 1 μm, more preferably 50 nm to 500 nm.

As a method for forming the first electrode 1, there are known vacuum film formation such as sputtering and vapor deposition, and film formation methods by various printing methods. In these processes, patterning using a shadow mask or the like is possible. Further, fine patterning by photolithography is also possible.
In the film-forming method by the printing method, it is possible to form various metal nano-particle inks or organometallic salt complex inks by coating pyrolysis or by sol-gel method. Specifically, various methods such as an inkjet method, a dispenser method, a relief printing method, an offset printing method, a gravure printing method, an intaglio printing method, and a screen printing method can be used. The first electrode is obtained by applying these methods and baking the coating film.

<Second electrode 2>
As the second electrode 2 used in the present invention, the same material and forming method as the first electrode 1 can be applied. Further, by using different materials for the first electrode 1 and the second electrode 2, a reversible state change can be formed, and a thin film solid secondary battery element with high performance can be manufactured.

<Charging layer 3>
The charging layer 3 used in the present invention can be a thin film in which a metal oxide semiconductor and an insulating material are mixed. As the oxide semiconductor, tin dioxide, titanium dioxide, or zinc oxide can be used. As the insulating material, various thermoplastic resins such as polyimide, various silicon, magnesium oxide, silicon dioxide, alumina and the like can be used.

  The charging layer 3 can be formed by applying thermal decomposition of a nanoparticle ink or organometallic complex ink of a semiconductor and an insulating material, or by a sol-gel method. In the case of using various types of silicon or thermoplastic resin as the insulating material, it can be formed by being dissolved in a solvent and mixed with a metal material.

  The charging layer 3 can use the same technique as the first electrode 1. In addition, from the viewpoint that patterning is not necessary, printing methods such as dipping, spraying, wire bar coating, spin coating, roller coating, blade coating, etc. can also be applied. Is possible.

  After the charge layer 3 is formed in contact with the first electrode 1 or in contact with the electron block layer 4 or the electron transport layer 5, the structure of the charge layer 3 is changed by ultraviolet irradiation. Thereby, the mixed thin film of the semiconductor and the insulator is changed to the charge layer 3 that accumulates charges.

<Electronic block layer 4>
The electron blocking layer 4 used in the present invention is not particularly limited as long as it can block electrons. Specifically, various p-type organic semiconductor materials and inorganic semiconductor materials are suitable, and more desirably, the inorganic semiconductor material is a material based on an oxide material such as NiO or Cu ₂ O. A material shallower (closer to the vacuum level) than the LUMO level of the charge layer material is suitable.

  Among them, polyethylenedioxythiophene: polystyrene sulfonic acid (PEDOT: PSS) is the optimum material. This is dispersed in an aqueous solvent, and a printing method such as a spin coating method that is excellent in film formation stability and film formation reproducibility can be applied. Thereby, large-area film formation can also be realized. Furthermore, since the material is suitable for energy matching with the charge layer and the energy level and specific resistance can be controlled, the charge / discharge characteristics can be improved and improved.

<Electron transport layer 5>
The electron transport layer is a material having a property of transporting electrons, and an inorganic oxide material is suitable in consideration of the compatibility with the charge layer material and the resistance to the charge layer manufacturing process. An oxide containing either or both of tungsten oxide is desirable. More desirable is a composite oxide material in which the oxide contains an oxide other than niobium oxide and tungsten oxide.

  Further, by forming all of the first and second electrodes 1 and 2, the charging layer 3, and the electronic block layer 4 by a printing method, process consistency can be ensured, and productivity improvement and cost reduction can be expected.

  Examples and comparative examples are shown below. However, these Examples and Comparative Examples do not limit the present invention.

<Examples A1 to A2 and Comparative Examples A1 to A7>

  An ITO film having a thickness of 200 nm was formed on a 40 mm square glass substrate that had been subjected to ultrasonic cleaning and UV ozone cleaning by a sputtering method through a shadow mask to form a first electrode. Next, the materials shown in Table 1 below were formed as electron transport layer materials by sputtering. The film thickness was all 40 nm.

Next, a mixed liquid of 0.24 g tin 2-ethylhexanoate, 1.28 ml toluene, 1.2 g silicon oil (TSF433) was prepared, and the prepared liquid was spin-coated on ITO, dried, By baking at 500 ° C. for 1 hour, a mixed film of tin oxide and silicon oil was obtained. Next, the mixed film was irradiated with ultraviolet rays. The irradiation intensity was 40 mW / cm ² (254 nm), and the irradiation time was 5 h. This formed the charge layer. Next, a nickel oxide film having a thickness of 150 nm was formed on the charging layer by sputtering using NiO as a target to form an electron blocking layer. Next, a 200-nm thick ITO film was formed on the electron blocking layer by a sputtering method through a shadow mask to form a second electrode, whereby a thin film solid secondary battery element was produced. A total of 4 sheets were produced by the same method.

The size of the active area that contributes to charging / discharging is 3 mm × 3 mm. As shown in FIG. 2, the active area is arranged at a total of five locations, in-plane center, upper right, lower right, upper left, lower left, and each charge / discharge characteristic was evaluated. (5 locations x 4). The charge capacity was 1 μAh / cm ² .

Table 1 shows the results when the constant current discharge was measured at 10 μA / cm ² and the element in which the discharge capacity was obtained was indicated as “◯” and the element that was not obtained was indicated as “x”. Furthermore, regarding the element from which the discharge capacity was obtained, the ratio of the discharge capacity to the charge capacity (discharge capacity / charge capacity) was expressed as a percentage of current capacity efficiency. As can be seen from these results, it can be seen that the use of the configuration of the present invention increases the current capacity efficiency and provides excellent battery characteristics.

<Examples (A1, A3-A6) and Comparative Example A1>
Except for using a mixed oxide of tungsten oxide and titanium oxide as the electron transport layer, Example A3 using the same material / layer configuration and production conditions as in Examples A1 to A2 and Comparative Examples A1 to A7 A6 was produced.
As a method for manufacturing the mixed oxide, a co-sputtering method in which a titanium oxide target and a tungsten oxide target were simultaneously sputtered was used. Here, each power was adjusted independently, the mixing ratio of tungsten oxide and titanium oxide was adjusted, and the relationship between the mixing ratio and the current capacity efficiency was examined.

  Table 2 shows the results of the sputtering power W (p) of tungsten oxide and the sputtering power Ti (p) of titanium oxide and the mixing ratio W / (W + Ti). The mixing ratio was obtained from the result of measuring the atomic weight of tungsten (W) and titanium (Ti) using EDS (energy dispersive X-ray spectroscopy) of the composition of the formed film. It can be seen that the mixing ratio can be controlled by adjusting each sputtering power. The relationship between the mixing ratio and current capacity efficiency is shown in FIG. It can be seen that by using the configuration of the present invention, the current capacity efficiency is further improved and excellent battery characteristics can be obtained.

<Examples A1, A2, A7 to A10>
The same material / layer configuration and production conditions as those in <Examples A1 to A2 and Comparative Examples A1 to A7> were used except that a mixed oxide of tungsten oxide and niobium oxide was used as the electron transport layer.
As in the case of <Examples A1, A3 to A6 and Comparative Example A1>, the mixed oxide is produced using a co-sputtering method in which a niobium oxide target and a tungsten oxide target are sputtered simultaneously, and each power is independently set. Adjustment was made to adjust the mixing ratio of tungsten oxide and niobium oxide, and the relationship between the mixing ratio and current capacity efficiency was examined. The mixing ratio was determined using EDS (energy dispersive X-ray spectroscopy) in the same manner as in Examples A1, A3-A6, and Comparative Example A1.

  FIG. 4 shows the relationship between the mixing ratio and current capacity efficiency. It can be seen that by using the configuration of the present invention, the current capacity efficiency is further improved and excellent battery characteristics can be obtained.

<Examples A2, A9, A11 to A14>
As the electron transport layer, the same material / layer configuration and production conditions as in <Examples A1 and A2 and Comparative Examples A1 and A7> were used except that a composite oxide of tungsten oxide, niobium oxide, and titanium oxide was used. .
As a method for producing the composite oxide, a co-sputtering method in which each of a niobium oxide target, a tungsten oxide target, and a titanium oxide target was simultaneously sputtered was used, as in <Examples A1, A3-A6, and Comparative Example A1>.
As a method for producing the composite oxide, the sputtering power of the tungsten oxide target and the niobium oxide target is fixed using the conditions of <Example A9>, and the sputtering power of the titanium oxide target is adjusted accordingly. The composite ratio was adjusted. The composite ratio was determined using EDS (energy dispersive X-ray spectroscopy) in the same manner as in Examples A1, A3 to A6 and Comparative Example A1.

  The relationship between this composite ratio and current capacity efficiency is shown in FIG. It can be seen that by using the configuration of the present invention, the current capacity efficiency is further improved and excellent battery characteristics can be obtained.

<Comparative Example B1>
An ITO film having a thickness of 200 nm was formed on a 40 mm square glass substrate that had been subjected to ultrasonic cleaning and UV ozone cleaning by a sputtering method through a shadow mask to form a first electrode. Next, by sputtering, a titanium oxide was used as a target to form a 40 nm niobium oxide film to form an electron transport layer.

Next, a mixed liquid of 0.24 g of tin 2-ethylhexanoate, 1.28 ml of toluene and 1.2 g of silicon oil (TSF433) was prepared, and the prepared liquid was spin-coated on niobium oxide and dried. By baking for 1 hour at 500 ° C., a mixed film of tin oxide and silicon oil was obtained. Next, the mixed film was irradiated with ultraviolet rays. The irradiation intensity was 40 mW / cm ² (254 nm), and the irradiation time was 5 h. This formed the charge layer. Next, a nickel oxide film having a thickness of 150 nm was formed on the charging layer by sputtering, using nickel oxide as a target, thereby forming an electron blocking layer. Next, a 200-nm thick ITO film was formed on the electron blocking layer by a sputtering method through a shadow mask to form a second electrode, whereby a thin film solid secondary battery element was produced.

The size of the active area that contributes to charging / discharging is 3 mm × 3 mm, and it is arranged in a total of five locations, in-plane center, upper right, lower right, upper left, lower left, and evaluated each charging / discharging characteristic (5 × 4 sheets). ). The charge capacity was 1 μAh / cm ² and constant current discharge was measured at 10 μA / cm ² .
The output potential was (average) −1.67V and (maximum−minimum) 0.20V.
The discharge capacities were (average) 0.595 μAh / cm ² and (maximum-minimum) 0.124 μAh / cm ² .

<Comparative Example B2>
A thin film solid secondary battery element was fabricated in the same manner as in Comparative Example B1, except that nickel oxide was deposited to a thickness of 150 nm and an electron blocking layer was formed, followed by annealing at 500 ° C. for 1 hour.
When similar evaluation was performed, charge / discharge characteristics could not be obtained.

<Example B1>
An ITO film having a thickness of 200 nm was formed on a 40 mm square glass substrate that had been subjected to ultrasonic cleaning and UV ozone cleaning by a sputtering method through a shadow mask to form a first electrode. Next, nickel oxide was deposited to a thickness of 150 nm by sputtering to form an electron blocking layer. Next, a mixed solution of 0.24 g of tin 2-ethylhexanoate, 1.28 ml of toluene and 1.2 g of silicon oil (TSF433) was prepared, and the prepared solution was spin-coated on nickel oxide and dried. By baking for 1 hour at 500 ° C., a mixed film of tin oxide and silicon oil was obtained. Next, the mixed film was irradiated with ultraviolet rays. The irradiation intensity was 40 mW / cm ² (254 nm), and the irradiation time was 5 h. This formed the charge layer. Next, by sputtering, a titanium oxide was used as a target to form a 40 nm niobium oxide film to form an electron transport layer. Next, a 200-nm thick ITO film was formed on the electron transport layer by a sputtering method through a shadow mask to form a second electrode, thereby producing a thin-film solid secondary battery element.

The size of the active area that contributes to charging / discharging is 3 mm × 3 mm, and it is arranged in a total of five locations, in-plane center, upper right, lower right, upper left, lower left, and evaluated each charging / discharging characteristic (5 × 4 sheets). ). The charge capacity was 1 μAh / cm ² and constant current discharge was measured at 10 μAh / cm ² .
The output potential was (average) -2.15V, (maximum-minimum) 0.08V.
The discharge capacities were (average) 0.690 μAh / cm ² and (maximum-minimum) 0.047 μAh / cm ² .
It was confirmed that both the output potential and the discharge capacity were improved. In particular, a great improvement in output potential was obtained.
Moreover, it was confirmed that the variation was greatly suppressed.

<Example B2>
A thin film solid secondary battery element was fabricated in the same manner as in Example B1, except that a nickel oxide film having a thickness of 150 nm was formed and an electron blocking layer was formed, followed by annealing at 500 ° C. for 1 hour.
When the same evaluation was performed, the output potential was (average) -2.21V.
The discharge capacity was (average) 0.724 μAh / cm ² .
Further improvement in output potential and discharge capacity was confirmed.

<Example B3>
A thin film solid secondary battery element was produced in the same manner as in Example B1, except that a 100 mm □ glass substrate was used.
When the same evaluation was performed, the output potential was (average) -2.15 V and (maximum-minimum) 0.07 V.
The discharge capacities were (average) 0.682 μAh / cm ² and (maximum-minimum) 0.049 μAh / cm ² .
It was confirmed that the charge / discharge variation did not change even when the substrate size was increased.

<Example B4>
A thin film solid secondary battery element was fabricated by the same method as in Example B1, except that a tungsten oxide film was formed to a thickness of 40 nm by sputtering and an electron transport layer was formed.
When the same evaluation was performed, the output potential was (average) -2.13V.
The discharge capacity was (average) 0.665 μAh / cm ² .
It was confirmed that an output potential and a discharge capacity equivalent to those of niobium oxide can be obtained.

<Comparative Example C1>
An ITO film having a thickness of 200 nm was formed on a 40 mm square glass substrate that had been subjected to ultrasonic cleaning and UV ozone cleaning by a sputtering method through a shadow mask to form a first electrode. Next, a mixed liquid of 0.24 g tin 2-ethylhexanoate, 1.28 ml toluene, 1.2 g silicon oil (TSF433) was prepared, and the prepared liquid was spin-coated on ITO, dried, By baking at 500 ° C. for 1 hour, a mixed film of tin oxide and silicon oil was obtained. Next, the mixed film was irradiated with ultraviolet rays. The irradiation intensity was 40 mW / cm ² (254 nm), and the irradiation time was 5 h. This formed the charge layer. Next, a nickel oxide film having a thickness of 150 nm was formed on the charging layer by sputtering using NiO as a target to form an electron blocking layer. Next, a 200-nm thick ITO film was formed on the electron blocking layer by a sputtering method through a shadow mask to form a second electrode, whereby a thin film solid secondary battery element was produced. A total of 4 sheets were produced by the same method.

The size of the active area that contributes to charging / discharging is 3 mm × 3 mm. As shown in FIG. 2, the active area is arranged at a total of five locations, in-plane center, upper right, lower right, upper left, lower left, and each charge / discharge characteristic was evaluated. (5 locations x 4). The charge capacity was 1 μAh / cm ² .
After charging, the output potential was (average) -1.73 V and (maximum-minimum) 0.24 V.
When the constant current discharge was measured at 10 μAh / cm ² , the discharge capacity was (average) 0.552 μAh / cm ² and (maximum−minimum) 0.099 μAh / cm ² .

<Comparative Example C2>
A thin film solid secondary battery element was produced in the same manner as in Comparative Example C1, except that a 100 mm □ glass substrate was used. When the same evaluation was performed, the output potential was (average) -1.71 V and (maximum-minimum) 0.39 V.
When the constant current discharge was measured at 10 μAh / cm ² , the discharge capacity was (average) 0.540 μAh / cm ² and (maximum−minimum) 0.136 μAh / cm ² .

<Example C1>
An ITO film having a thickness of 200 nm was formed on a 40 mm square glass substrate that had been subjected to ultrasonic cleaning and UV ozone cleaning by a sputtering method through a shadow mask to form a first electrode. Next, a mixed liquid of 0.24 g tin 2-ethylhexanoate, 1.28 ml toluene, 1.2 g silicon oil (TSF433) was prepared, and the prepared liquid was spin-coated on ITO, dried, By baking at 500 ° C. for 1 hour, a mixed film of tin oxide and silicon oil was obtained. Next, the mixed film was irradiated with ultraviolet rays. The irradiation intensity was 40 mW / cm ² (254 nm), and the irradiation time was 5 h. This formed the charge layer. Next, a PEDOT: PSS solution diluted with IPA was applied onto the charge layer by spin coating and dried at 150 ° C. for 10 minutes to form an electron blocking layer having a thickness of 100 nm. Next, a 100 nm thick Au film was formed on the electron blocking layer by a vacuum vapor deposition method through a shadow mask, and a second electrode was formed to produce a thin film solid secondary battery element. A total of 4 sheets were produced by the same method.

The size of the active area that contributes to charging / discharging is 3 mm × 3 mm. As shown in FIG. 2, the active area is arranged at a total of five locations, in-plane center, upper right, lower right, upper left, lower left, and each charge / discharge characteristic was evaluated. (5 locations x 4). The charge capacity was 1 μAh / cm ² .
After charging, the output potential was (average)-1.30V, (maximum-minimum) 0.03V.
When the constant current discharge was measured at 10 μAh / cm ² , the discharge capacity was (average) 0.532 μAh / cm ² (maximum−minimum) 0.017 μAh / cm ² ,
It was confirmed that variation in charge / discharge characteristics was greatly suppressed.

<Example C2>
A thin film solid secondary battery element was produced in the same manner as in Example C1, except that a 100 mm □ glass substrate was used. When a similar evaluation was conducted,
The output potentials were (average) -1.29V and (maximum-minimum) 0.05V.
When the constant current discharge was measured at 10 μAh / cm ² , the discharge capacity was (average) 0.535 μAh / cm ² and (maximum-minimum) 0.023 μAh / cm ² , and even if the substrate size was increased, the variation was It was confirmed that it did not change.

<Example C3>
A thin-film solid secondary battery element was produced in the same manner as in Example C2, except that the PEDOT: PSS film thickness was 30 nm. When the same evaluation was performed, the output potential was (average) −0.44V, and (maximum−minimum) 0.11V.
When the constant current discharge was measured at 10 μAh / cm ² , the discharge capacity was (average) 0.025 μAh / cm ² , (maximum-minimum) 0.013 μAh / cm ² ,
It was confirmed that sufficient charge / discharge characteristics could not be obtained at least with a film thickness of 30 nm.

<Example C4>
A thin film solid secondary battery element was produced in the same manner as in Example C2, except that a stainless steel foil substrate with a SiO ₂ thin film (100 μm thickness) was used as the substrate. When the same evaluation was performed, the output potential was (average) −1.29 V and (maximum−minimum) 0.08V.
When the constant current discharge was measured at 10 μAh / cm ² , the discharge capacity was (average) 0.523 μAh / cm ² (maximum−minimum) 0.041 μAh / cm ² ,
A flexible thin-film solid secondary battery element could be produced.

  According to each of the above Examples and Comparative Examples, it was found that a thin film solid secondary battery element having excellent productivity and improved charge / discharge characteristics can be provided.

DESCRIPTION OF SYMBOLS 1 1st electrode 2 2nd electrode 3 Charging layer 4 Electron block layer 5 Electron transport layer 10 Board | substrate

Japanese Patent No. 3561580 Japanese Patent No. 2934450 Japanese Patent No. 3116857 Japanese Patent No. 3531866 JP 2004-179158 A WO2008 / 053561

Hiroshi Hatakeyama, “Research and Development of Semiconductor Secondary Batteries”, Hiroshima University New Technology Briefing 2010, November 25, 2010, Internet <URL: http://www.hiroshima-u.ac.jp/upload/ 83 / riezon / 2010 / hp / a-2kajiyama.pdf> Guella Technology website, Internet <URL: http: //www.guala-tec.co.jp/technology/index.html>

Claims (10)

A first electrode, an electron transport layer, a charge layer, an electron block layer, and a second electrode are laminated in this order on the substrate,
The charging layer includes an inorganic material,
The electron transport layer is made of an inorganic oxide material, and the inorganic material oxide contains niobium oxide or tungsten oxide.   A thin-film solid secondary battery element, wherein a first electrode, an electron block layer, a charge layer, an electron transport layer, and a second electrode are laminated on a substrate in this order. A first electrode, a charging layer, an electron block layer, and a second electrode are laminated in this order on the substrate,
The charging layer includes an inorganic material,
The electron blocking layer includes an organic material,
A thin-film solid secondary battery element having at least one organic-inorganic interface.   The thin-film solid secondary battery element according to claim 1, wherein the inorganic oxide material is a composite oxide containing an inorganic oxide other than niobium oxide and tungsten oxide.   The thin film solid secondary battery element according to claim 1, wherein the electron transport layer is formed by a sputtering method.   3. The thin film solid secondary battery element according to claim 2, wherein the electron blocking layer is made of an insulating inorganic oxide.   3. The thin film solid secondary battery element according to claim 2, wherein the electron block layer is made of nickel oxide.   8. The thin film solid state secondary battery element according to claim 2, wherein the electron transport layer is made of an inorganic oxide material, and the inorganic material oxide contains niobium oxide or tungsten oxide.   The thin film solid state secondary battery element according to claim 3, wherein the organic material is a material dispersed or soluble in a solvent.   The thin film solid secondary battery element according to claim 3 or 9, wherein the organic material is made of polyethylene dioxythiophene: polystyrene sulfonic acid.