Physical secondary battery

Abstract

A physical secondary battery (100) comprises: a first electrode (10); a second electrode (20); and a p-type semiconductor layer (30) disposed between the first electrode (10) and the second electrode (20).

Description

physical secondary battery

[0001] The present invention relates to a physical secondary battery.

[0002] Chemical batteries such as lithium-ion secondary batteries are now widely used. A typical lithium-ion secondary battery includes a positive electrode using a lithium-containing transition metal composite oxide as an active material, a negative electrode using a material capable of absorbing and releasing lithium ions as an active material, a non-aqueous electrolyte, and a separator (see, for example, JPH5-242911A).

[0003] In recent years, secondary batteries have come to be used in a wide range of applications, not only in portable electronic devices but also in applications that are closely connected to people, such as stationary batteries for electric vehicles, smart grids, humanoid robots, drones, and power load leveling systems. This has led to expectations for the development of lightweight, compact secondary batteries with high input / output performance, high capacity, long life, and high safety, which surpass conventional lithium-ion secondary batteries.

[0004] Conventional lithium-ion secondary batteries have limitations in output and capacity per unit weight. Furthermore, their complex structure, which includes a positive electrode, a negative electrode, an electrolyte, and a separator, limits their ability to be made smaller and lighter. Furthermore, because lithium-ion secondary batteries involve chemical reactions, they have inherent problems such as long charging times, electrolyte degradation, heat generation, short lifespan, and safety.

[0005] An object of the present invention is to provide a secondary battery that has high input / output performance, high capacity, high safety, and can be miniaturized.

[0006] According to one aspect of the present invention, a physical secondary battery includes a first electrode, a second electrode, and a p-type semiconductor layer provided between the first electrode and the second electrode.

[0007] Fig. 1 is a schematic diagram of a physical secondary battery according to an embodiment of the present invention, and Fig. 2 is a schematic diagram of a physical secondary battery according to a modified example of the embodiment of the present invention.

[0008] Hereinafter, a physical secondary battery according to an embodiment of the present invention will be described with reference to the drawings.

[0009] FIG. 1 is a schematic diagram showing a physical secondary battery of this embodiment.

[0010] The physical secondary battery 100 of this embodiment includes a first electrode 10, a second electrode 20, and a p-type semiconductor layer 30 that is provided between the first electrode 10 and the second electrode 20 and functions as a storage layer. One of the electrodes 10, 20 functions as a positive electrode and the other as a negative electrode, and by applying a large current in one direction between the electrodes, polarization is induced in the p-type semiconductor layer 30, allowing charging.

[0011] The p-type semiconductor layer 30 is made of, for example, an oxide-based semiconductor or a chalcogenide-based semiconductor. Examples of such semiconductors include zinc oxide (ZnO), cobalt oxide (CoO), nickel oxide (NiO), copper oxide (CuO), tin oxide (SnO), and molybdenum sulfide (MoS). ２ ), tungsten selenide (WSe ２ ), tin sulfide (SnS), and germanium selenide (GeSe). In other words, the p-type semiconductor layer 30 includes at least one of the above materials.

[0012] Furthermore, the p-type semiconductor layer 30 of this embodiment is composed of at least one nanosheet film 40. The nanosheet film 40 is a two-dimensional nanoscale material having a thickness on the order of nanometers, and the horizontal dimension can be several hundred times that thickness or more. The nanosheet film 40 is formed, for example, from a sheet-like material having a thickness of one or several atoms. In other words, the nanosheet film 40 is formed from one or several layers of atoms. Such a nanosheet film 40 can be obtained, for example, by exfoliation from an inorganic layered compound. Various inorganic layered compounds may be used, but for example, preferred are oxide-based semiconductors and chalcogenide-based semiconductors having the composition formula ZnO, ZnO 1-ｘ N ｘ , CoO, NiO, Ni 1-ｘ Mn ｘ O, Ni 1-ｘ Fe ｘ O, Ni 1-ｘ Co ｘ O, CuO, MoS ２ , Mo 1-ｘ W ｘ S ２ , WSe ２ , W 1-ｘ Mo ｘ Se ２, SnS, and GeSe, which may be used alone or in combination or as a compound. In other words, the p-type semiconductor layer 30 contains at least one of the above composition formulas.

[0013] Specifically, the p-type semiconductor layer 30 of this embodiment is configured by laminating composite nanosheet films 41 each formed by arranging a plurality of nanosheet films 40 in a planar manner. The composite nanosheet film 41 is intended to be a film formed by densely arranging nanosheet films 40 in which single layers of an inorganic layered material are exfoliated without overlapping. In other words, the composite nanosheet film 41 is formed by arranging a plurality of nanosheet films 40 without overlapping each other (specifically, without overlapping in the thickness direction) and without gaps. In FIG. 1, the boundaries of the nanosheet films 40 in the composite nanosheet film 41 are schematically indicated by dotted lines. The p-type semiconductor layer 30 may be formed from a single composite nanosheet film 41. The p-type semiconductor layer 30 may be a multilayer film formed by laminating composite nanosheet films 41 of the same type (in other words, having the same configuration), or a multilayer film formed by laminating a combination of two or more composite nanosheet films 41 of different types (in other words, having different configurations). The p-type semiconductor layer 30 may be configured by stacking nanosheet films 40 or may be configured by a single layer of nanosheet film 40 .

[0014] The p-type semiconductor layer 30 is not limited to being formed from the nanosheet film 40 or the composite nanosheet film 41 as described above. The p-type semiconductor layer 30 can be formed by various methods, and for example, a thin-film p-type semiconductor layer 30 can be formed by a physical vapor deposition method such as sputtering, resistance heating evaporation, electron beam evaporation, molecular beam epitaxy, or ion plating, or a chemical vapor deposition method such as thermal CVD, photo-CVD, plasma CVD, atomic layer deposition, or metalorganic vapor phase epitaxy.

[0015] The first electrode 10 is preferably selected from the group consisting of a transparent conductive oxide film and a metal film, which reduces contact resistance with the p-type semiconductor layer 30 and enables efficient charging and discharging.

[0016] The transparent conductive oxide film contains, for example, at least one selected from the group consisting of tin-doped indium oxide (ITO), aluminum-doped zinc oxide (AZO), antimony-doped tin oxide (ATO), boron-doped zinc oxide (BZO), and niobium-doped titanium oxide (TNO).

[0017] The metal film contains at least one selected from the group consisting of, for example, gold (Au), platinum (Pt), copper (Cu), and nickel (Ni). In addition, silver (Ag), iron (Fe), tin (Sn), zinc (Zn), aluminum (Al), indium (In), chromium (Cr), etc. may also be used.

[0018] The first electrode 10 preferably has a thickness of 10 nm or more and 10 μm or less, but the thickness is not limited to this. The first electrode 10 made of the above-mentioned material may be formed on a partial region of the p-type semiconductor layer 30. In this case, as long as the thickness of the first electrode 10 is within the above-mentioned range, an insulating substrate or insulating film on which the first electrode 10 and the p-type semiconductor layer 30 made of the above-mentioned material are patterned and partially disposed can be used. When the first electrode 10 is a thin film on an insulating substrate, it can be partially disposed on the insulating substrate by masking and physical vapor deposition such as sputtering, resistance heating evaporation, electron beam evaporation, molecular beam epitaxy, or ion plating.

[0019] The second electrode 20 may have the same configuration as the first electrode 10. The second electrode 20 is preferably formed of the same metal as the first electrode 10, and includes, for example, at least one selected from the group consisting of gold (Au), platinum (Pt), copper (Cu), and nickel (Ni). There are no particular limitations on the thickness of the second electrode 20. When the second electrode 20 is formed of the above metals, the thickness is preferably 5 nm or more and 1 μm or less, but the thickness is not limited to the above. As long as the thickness of the second electrode 20 is within the above range, the second electrode 20 can be formed by physical vapor deposition or the like, by masking so that a portion of the second electrode 20 is positioned on the p-type semiconductor layer 30, as with the first electrode 10.

[0020] The thickness of the p-type semiconductor layer 30 is preferably 100 nm or less. Within this range, a large current difference can be obtained between on and off, and a high capacitance density can be achieved. However, the thickness of the p-type semiconductor layer 30 is not limited to the above.

[0021] Here, the p-type semiconductor layer 30 formed from the nanosheet film 40 (composite nanosheet film 41) can be formed by the following three steps. Step 1: A colloidal dispersion is prepared in which nanosheet film components are dispersed in a dispersion medium. Step 2: Using the colloidal dispersion, a stack (p-type semiconductor layer 30) of nanosheet films 40 (composite nanosheet film 41), which are nanosheet monolayer films, is formed on the first electrode 10. Step 3: The second electrode 20 is formed on the stack of nanosheet films 40 (composite nanosheet film 41). By the above method, the physical secondary battery 100 of this embodiment described above is obtained. The methods for forming the inorganic layered material, first electrode 10, and second electrode 20 are as described above, so further explanation is omitted.

[0022] Each step is described in detail below. In step 1, the powder of the inorganic layered compound described above is placed in an aprotic polar solvent, such as dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), or formamide, and subjected to ultrasonic treatment (treatment frequency: 20 kHz-1 MHz, treatment time: 20 minutes to 3 hours). This peels off the layers that make up the layered structure, resulting in a colloidal dispersion in which nanosheet membrane components are dispersed. The polar solvent is then evaporated, and the mixture is dispersed in pure water to obtain an aqueous colloidal dispersion.

[0023] In step 2, the nanosheet film 40 (composite nanosheet film 41) and its laminate are preferably formed by a method selected from the group consisting of the Langmuir-Blodgett (LB) method, the layer-by-layer (LBL) method, the spin coating method, the dropping method, the slit coating method, the bar coating method, and the dip coating method.

[0024] The LB method is a technique for forming a nanosheet film 40 (composite nanosheet film 41) using surface pressure. A colloidal dispersion is spread in a trough (water tank) in which a first electrode 10 is immersed, and the nanosheet film 40 is suspended at the gas-liquid interface. The surface of the colloidal dispersion is compressed to a certain surface pressure to form a gas-liquid interface, and then the first electrode 10 is pulled up vertically. This transfers the nanosheet film 40 onto the insulating substrate or insulating film on which the first electrode 10 is disposed. By repeating this process, a laminate of nanosheet films 40 is formed on the first electrode 10.

[0025] With the LB method, the nanosheet films 40 do not overlap each other on the surface of the developing solution, and a monolayer film accumulated in the planar direction is formed at the gas-liquid interface, so that an extremely uniform and high-quality nanosheet film 40 can be formed on the first electrode 10.

[0026] The LBL method, also known as layer-by-layer adsorption, is a technique for forming a nanosheet film 40 (composite nanosheet film 41) by utilizing electrostatic interactions. Counterions (e.g., cationic polymers) are applied to an insulating substrate or insulating film on which a first electrode 10 is disposed, and then a colloidal dispersion is applied. This causes electrostatic interactions with the counterions, resulting in strong bonding of the nanosheets to form the nanosheet film 40. This process is repeated until the desired thickness is achieved, and the counterions are removed by irradiation with light such as ultraviolet light. This forms a laminate of nanosheet films 40 on the first electrode 10.

[0027] The spin coating method uses a colloidal dispersion as the spin coating material. The colloidal dispersion is dropped onto an insulating substrate or insulating film on which a first electrode 10 rotating at high speed is provided, and a uniform nanosheet monolayer film, a nanosheet film 40 (composite nanosheet film 41), is obtained by centrifugal force. This process is repeated to obtain a laminate of nanosheet films 40. The use of the spin coating method makes it relatively easy to obtain a laminate of nanosheet films 40.

[0028] The dropping method involves dropping a colloidal dispersion onto an insulating substrate or an insulating film on which the first electrode 10 is provided using a pipette or the like, and then drying the resulting solution. This results in a nanosheet film 40 (composite nanosheet film 41). By repeating this process, a stack of nanosheet films 40 can be obtained.

[0029] In the dip coating method, the insulating film on which the first electrode 10 is provided or the insulating film on which the first electrode 10 is provided is immersed in a colloidal dispersion, and then the film is pulled up and dried. In this case, as in the drop method, a nanosheet film 40 (composite nanosheet film 41) is obtained, and by repeating this process, a laminate of nanosheet films 40 is obtained.

[0030] Bar coating and slit coating methods can also be employed using existing methods with colloidal dispersions.

[0031] The physical secondary battery 100 of this embodiment, as described above, is an all-solid-state secondary battery whose principles and structure are completely different from those of conventional chemical batteries such as lithium-ion secondary batteries. The p-type semiconductor layer 30 functions as a storage layer. For example, the basic configuration utilizes a storage layer in which a p-type semiconductor is thinned to a thickness of 100 nm or less. By applying a large current to the electrodes 10 and 20, a polarization phenomenon (charge accumulation) is induced in the p-type semiconductor layer 30, enabling storage of electricity. Specifically, during charging, a high-potential terminal of an external power supply is electrically connected to one side of the p-type semiconductor layer 30, and a low-potential terminal is electrically connected to the opposite side of the p-type semiconductor layer 30, thereby generating polarization of positive charge carriers (holes) on one side of the p-type semiconductor layer 30. During discharging, holes migrate to the opposite side, and further, charge is released to an external circuit, resulting in the flow of electricity. By utilizing this polarization phenomenon (hole transfer) and charging at a large current, preferably from 100 C to 1000 C, it is possible to achieve both high input / output performance and high capacity exceeding those of lithium secondary batteries, while also achieving a shorter charging time and higher cycle stability.

[0032] Furthermore, the physical secondary battery 100 of this embodiment utilizes hole migration, which has higher mobility, rather than the ion migration used in conventional lithium-ion secondary batteries. This provides the effect of achieving both high input / output performance and rapid charging performance due to higher hole mobility than conventional lithium-ion secondary batteries. Furthermore, the use of the nanosheet film 40 can achieve higher hole mobility, thereby further improving high input / output performance and rapid charging performance.

[0033] Furthermore, the physical secondary battery 100 of this embodiment does not involve chemical reactions during charging and discharging, and therefore has the effect of achieving high speed, long life, and high safety.

[0034] As described above, the physical secondary battery 100 of this embodiment operates on the principle of the movement of positive charge carriers (holes), and therefore can be said to be a battery based on the principle of a semiconductor battery. In fact, the physical secondary battery 100 of this embodiment has a simple structure made only of a solid material, a p-type semiconductor, and is therefore advantageous in terms of manufacturing, cost, and lifespan, and can also be easily made lightweight and compact.

[0035] Furthermore, in conventional lithium-ion secondary batteries, the positive and negative electrodes are formed by kneading and coating materials, which limits the size and thickness of the first electrode 10 and the second electrode 20, and therefore limits the size of the battery. In contrast, the physical secondary battery 100 of this embodiment only requires the formation of a p-type semiconductor layer 30 with a film thickness of, for example, 100 nm or less, and even a small p-type semiconductor layer 30 measuring 2 mm square can be easily manufactured, making the physical secondary battery 100 smaller than conventional lithium-ion secondary batteries. Therefore, the physical secondary battery 100 of this embodiment can be formed into a small chip shape and mounted on an electronic substrate of an electronic device or safely installed in a small space such as a cardiac pacemaker.

[0036] The physical secondary battery 100 of this embodiment can also be mounted on an electronic circuit board of an electronic device and function as a power source or auxiliary power source for the electronic device. For example, by mounting the physical secondary battery 100 on the electronic circuit board of a personal computer (as an electronic device) and functioning as an auxiliary power source, it is possible to retain the contents of volatile memory and mitigate shock to electronic components when power supply from the main power source is interrupted due to a power outage or the like. Furthermore, even when the main power source is turned off, the physical secondary battery 100 can supply power to the volatile memory and retain the contents. Alternatively, the physical secondary battery 100 can be mounted on the electronic circuit board of a pacemaker (as an electronic device) and function as the main power source. The physical secondary battery 100 is highly safe because it does not involve chemical reactions during operation. Furthermore, the physical secondary battery 100 is a rechargeable secondary battery, unlike the non-rechargeable primary batteries used in conventional pacemakers, and is therefore suitable as the main power source for a pacemaker.

[0037] 2 , the physical secondary battery 100 of this embodiment may have the p-type semiconductor layer 30 formed in a case 60 and provided on an electronic substrate 51. The case 60 may be formed of a conductive material such as copper, or may be formed by disposing a conductor inside a ceramic container. The case 60 has a concave main body 61 mounted on the electronic substrate 51 and a lid 62 that closes the opening of the main body 61. An O-ring 65 formed of an insulator such as insulating rubber is provided between the main body 61 and the lid 62 as a sealing member to prevent electrical connection between the main body 61 and the lid 62.

[0038] The first electrode 10 is electrically connected to the lid portion 62 of the case 60 via a current-carrying portion 70 such as a lead wire, wire, or conductive paste. The second electrode 20 is provided on the body portion 61 of the case 60. As a result, the second electrode 20 is electrically connected to the body portion 61, and the first electrode 10 is electrically connected to the lid portion 62. The body portion 61 and the lid portion 62 of the case 60 are electrically connected to the circuit of the electronic board 51, and the physical secondary battery 100 functions as a power source or auxiliary power source for an electronic device.

[0039] As described above, the physical secondary battery 100 can be easily made small and lightweight, and can be installed on the electronic board 51 of an electronic device and used as a power source or auxiliary power source. Furthermore, since the p-type semiconductor layer 30 of the physical secondary battery 100 does not undergo chemical changes during charging and discharging, the battery does not expand or contract as in conventional lithium-ion secondary batteries, and the physical secondary battery 100 can maintain its small chip shape. Furthermore, since the p-type semiconductor layer 30 of the physical secondary battery 100 is housed within the case 60, secondary safety effects are achieved, such as preventing deterioration of the physical secondary battery 100 due to heat from the electronic device and preventing leakage when the electronic device is submerged in water.

[0040] In the configuration shown in FIG. 2 , the p-type semiconductor layer 30 of the physical secondary battery 100 may be electrically connected to the side wall 61b of the main body 61 of the case 60 via the current-carrying portion 70. In this case, for example, an O-ring made of an insulator may be provided between the bottom plate 61a and the side wall 61b of the main body 61 to prevent electrical connection between the bottom plate 61a and the side wall 61b. The case 60 may also be formed of an insulating material such as silica. For example, this configuration corresponds to the configuration shown in FIG. 1 being placed in a cylindrical can. In this case, for example, a through-hole may be formed in the case 60 and the current-carrying portion 70 may be provided in the through-hole to electrically connect the p-type semiconductor layer 30 to the outside of the case 60.

[0041] 2 , one surface (the upper surface shown in FIG. 2 ) of the p-type semiconductor layer 30 may be electrically connected to the lid portion 62 of the case 60 via the current-carrying portion 70, and the other surface (the upper surface shown in FIG. 2 ) of the p-type semiconductor layer 30 may be provided on the main body portion 61 of the case 60. In this case, the lid portion 62 directly and electrically connected to one surface of the p-type semiconductor layer 30 corresponds to the first electrode 10, and the main body portion 61 directly and electrically connected to the other surface of the p-type semiconductor layer 30 corresponds to the second electrode 20. In this configuration, only the p-type semiconductor layer 30 is provided in the case 60, eliminating the need for a complex configuration.

[0042] Alternatively, the p-type semiconductor layer 30 of the physical secondary battery 100 may be formed on an insulating member such as a resin film or silica having dot-like conductive material on the front and back surfaces thereof, to form a unit, which may then be housed in the case 60. Specifically, the physical secondary battery 100 is housed in the case 60 with the insulating member mounted on the bottom plate 61a of the main body 61 of the case 60. The negative electrode terminal may be electrically connected to the main body 61 via a conductive part provided in a through-hole of the insulating member. Note that the part where the conductive material is formed may be linear rather than dot-like. In this case, the linear conductive material may be formed so as to penetrate the insulating member in the thickness direction, thereby eliminating the need for a through-hole and a conductive part.

[0043] Furthermore, the physical secondary battery 100 may be provided on the electronic board 51 of the electronic device without the case 60. In other words, the physical secondary battery 100 may be provided on the electronic board 51 of the electronic device via a member, or may be provided directly on the electronic board 51 of the electronic device.

[0044] Furthermore, the physical secondary battery 100 may further include a coil (not shown) for wireless power supply electrically connected to the first electrode 10 and the second electrode 20, and may be able to charge power via the coil. This allows the physical secondary battery 100 to be charged contactlessly even when it is installed on the electronic board 51 of an electronic device. In particular, when the physical secondary battery 100 is used as the main power source for a pacemaker, the physical secondary battery 100 can be charged by wireless power supply before it runs out of power. As a result, the physical secondary battery 100 as the main power source for a pacemaker is rechargeable because it is a secondary battery and can be charged externally by wireless power supply, eliminating the need for battery replacement through surgery, as was previously required, and allowing for semi-permanent use.

[0045] Examples of the physical secondary battery 100 according to this embodiment of the present invention will be described below, but the present invention is not limited to the following examples.

[0046] Example 1 In Example 1, a physical secondary battery 100 was manufactured in which the p-type semiconductor layer 30 was a nickel oxide thin film. The nickel oxide thin film (film thickness: 100 nm) was formed by sputtering under the following conditions: Target: nickel oxide, Discharge gas: argon gas, Gas flow rate: 30 sccm, Gas pressure: 1.2×10 -５ Pa DC power: 100 W Distance between target and substrate (TS distance): 40 mm Processing time: 140 minutes

[0047] The physical secondary battery 100, in which the p-type semiconductor layer 30 is formed from a nickel oxide thin film, was charged at a current value of 100 C to 1000 C to evaluate its battery characteristics. Furthermore, as a comparative example of the physical secondary battery 100, a stacked lithium ion secondary battery was fabricated from nickel manganese cobalt oxide lithium BC-618 manufactured by Sumitomo 3M Limited, and evaluated by the method described below.

[0048] (Evaluation of Battery Initial Capacity) The 1C discharge capacity in the specified potential range of 2V-4.3V of the comparative example was set to 100, and a comparative capacity performance evaluation of the secondary battery was performed. Furthermore, a rectangular battery can was used as the battery shape this time, and a laminated battery was formed. Furthermore, the 100C / 1C discharge capacity ratio was measured to evaluate high-output performance. Similarly, the 100C / 1C charge capacity ratio was measured to evaluate input performance and rapid chargeability.

[0049] (Nail penetration test) A 2.7 mm diameter iron round nail was penetrated into a fully charged secondary battery at a speed of 5 mm / sec in a room temperature environment, and the heat generation state and appearance were observed. The results are shown in Table 1 below. In Table 1, secondary batteries that did not undergo any change in temperature or appearance are indicated as "OK," and secondary batteries that did undergo any change in temperature or appearance are indicated as "NG."

[0050] (Overcharge test) A current of 200% charge rate was maintained, and it was determined whether or not any change occurred in the appearance for 15 minutes or more. The results are shown in Table 1 below. In Table 1, secondary batteries that did not exhibit any abnormalities are indicated as "OK," and secondary batteries that exhibited changes (such as swelling or explosion) are indicated as "NG."

[0051] (Life Test) The secondary batteries of Example 1 and Comparative Example, each having a specified potential range of 1 V to 5 V, were charged at 1 C / 5 V at 25° C., and then discharged at 1 C / 1 V for 3,000 cycles and 10,000 cycles, and the capacity loss was compared with the initial capacity.

[0052] Table 1 shows the evaluation results of the physical secondary battery 100 of Example 1.

[0053] As shown in Table 1, it was confirmed that the physical secondary battery 100 of Example 1 exhibited excellent charging characteristics even at high rates, realizing rapid charging. Furthermore, unlike stacked lithium-ion secondary batteries, it exhibited excellent discharge characteristics even at high rates, and was confirmed to have both high output and high capacity characteristics. Furthermore, it was confirmed that the physical secondary battery 100 of Example 1 is an all-solid-state secondary battery whose principle and structure are completely different from chemical batteries such as conventional lithium-ion secondary batteries, and that it also has the high safety characteristic of all-solid-state batteries. As described above, Example 1 demonstrates that the physical secondary battery 100 of this embodiment is an excellent power storage device that surpasses conventional lithium secondary batteries.

[0054] Example 2 In Example 2, a physical secondary battery 100 was manufactured in which the p-type semiconductor layer 30 (0.08 μm) was formed from a nickel oxide nanosheet.

[0055] After peeling off the nickel hydroxide, the solution was heated and dehydrated to produce a green sol solution (colloidal dispersion) in which rectangular nickel oxide nanosheets with a thickness of approximately 1 nm and a lateral size of approximately 1 μm were dispersed. Using this colloidal dispersion, a laminate of a composite nanosheet film 41 (thickness 0.08 μm) formed of multiple nanosheet monolayer films (nanosheet films 40) was formed on an ITO substrate by the LB method as the first electrode 10. The ITO substrate was irradiated with ultraviolet light in an ozone atmosphere and surface-cleaned.

[0056] After spreading a colloidal dispersion containing nickel oxide nanosheet film material in an LB trough thoroughly washed with acetone, we waited 30 minutes for the water surface to stabilize and the temperature of the lower layer liquid to become constant. The ITO substrate was then placed in the LB film-forming apparatus. The following series of operations constituted one cycle, and 10 cycles were repeated to form a laminate consisting of multiple nanosheet monolayer films. (1) The surface was compressed by moving the barrier at a compression rate of 0.5 mm / min, gathering the nanosheet films 40 dispersed at the air-liquid interface. After a constant pressure was reached, the system was left to stand for 30 minutes. (2) The ITO substrate was pulled vertically at a pulling rate of 0.8 mm / min, and the nanosheet films 40 gathered at the air-liquid interface were attached to the substrate, forming a composite nanosheet film 41 (thickness 0.08 μm) in which the nanosheet films 40 were densely arranged without overlapping.

[0057] The resulting laminate was irradiated with ultraviolet light (wavelength: 200 to 300 nm, intensity: 1 mW / cm) using a xenon light source. ２ ) for 24 hours to decompose and remove organic matter. Next, a gold electrode was deposited as a second electrode 20 on the laminate using a vacuum deposition apparatus (SVC-700, manufactured by Sanyu Electronics Co., Ltd.), producing a physical secondary battery 100 of Example 2. This was charged at 1000 C with one side as the positive electrode and the other side as the negative electrode.

[0058] Table 2 shows the evaluation results of the physical secondary battery 100 of Example 2.

[0059] As shown in Table 2, the physical secondary battery 100 of Example 2 exhibited excellent charging characteristics even at high-rate charging, confirming that rapid charging was achieved. In particular, the high hole mobility of the nanosheet film 40 provided the effect of achieving both higher input / output performance and faster charging performance than the thin film of Example 1. As described above, Example 2 demonstrated that the physical secondary battery 100 of this embodiment is an excellent power storage device that surpasses conventional lithium secondary batteries, and further demonstrated the usefulness of the nanosheet film 40.

[0060] Example 3 In Example 3, similarly to Example 2, a physical secondary battery 100 was manufactured in which the p-type semiconductor layer 30 (0.08 μm) was formed from a nickel oxide nanosheet film and the layered structure was further changed.

[0061] A conductive metal paste, such as a copper powder-containing paint, is applied to the front and back of an insulating film, such as a PET film, at desired intervals in a regular dot pattern. Furthermore, by applying tape or masking at regular intervals, or by intermittent coating, inkjet patterning, or 3D printer patterning when forming the p-type semiconductor layer 30, areas where the nanosheet film 40 will not be formed are provided at regular intervals. A nickel oxide nanosheet monolayer film (nanosheet film 40) is formed as the p-type semiconductor layer 30 on this insulating film as in Example 2, and then cut to the desired size and stacked. When stacking, if tape is applied at regular intervals, the tape is removed before stacking. A conductive metal paste is applied to each end group on the side where the conductive metal paste formation points are located in the stacked group, so as not to contact the p-type semiconductor portion, and then dried. Alternatively, a metal needle, such as a stapler, is inserted (pierced) into the conductive metal film formation portion from the metal film formation side, and a secondary battery is obtained by connecting each of these as a positive electrode and a negative electrode to an external circuit. At this time, the positive electrode side is connected to an external circuit by bringing the metal needle or the end conductive paint forming portion into contact with the upper end of the uppermost p-type semiconductor on the side opposite the insulating film.

[0062] The physical secondary battery 100 thus obtained was subjected to a performance evaluation in the same manner as in Example 2, and the results are shown in Table 3.

[0063] As shown in Table 3, the physical secondary battery of Example 3 exhibited the effect of achieving both higher input / output performance and faster charging performance than the thin film of Example 1 due to the high hole mobility of the nanosheet film 40. In particular, it was confirmed that the laminated structure improved the high input / output performance, the fast charging performance, and the life characteristics. As described above, Example 3 demonstrated that the physical secondary battery of the present invention is an excellent power storage device that surpasses conventional lithium secondary batteries, and further demonstrated the usefulness of the laminated structure.

[0064] Example 4 In Example 4, zinc oxide (ZnO), cobalt oxide (CoO), nickel oxide (NiO), tin oxide (SnO), molybdenum sulfide (MoS ２ ), tungsten selenide (WSe２ Nanosheet films 40 of ZnSe, ZnSe, and germanium selenide (GeSe) were synthesized in the same manner as in Example 2, and a physical secondary battery 100 in which the p-type semiconductor layer 30 was formed from each nanosheet film 40 was manufactured.

[0065] Specifically, the colloidal dispersion of the nanosheet film 40 was dropped onto a Pt substrate, which would serve as the first electrode 10, using a pipette or the like, and then dried to produce a nanosheet monolayer film (nanosheet film 40). This process was repeated to produce a stack of nanosheet monolayer films. Next, a Pt electrode was vapor-deposited onto the nanosheet monolayer film as the second electrode 20 using a vacuum vapor deposition apparatus (SVC-700, manufactured by Sanyu Electronics Co., Ltd.), thereby producing the physical secondary battery 100 of Example 4. Battery characteristics were evaluated by bringing a microprober into contact with the electrodes 10 and 20 and using a Keithley Semiconductor Parameter Analyzer (4200-SC).

[0066] Table 4 shows the evaluation results of the physical secondary battery of Example 4.

[0067] As shown in Table 4, it was confirmed that the physical secondary battery 100 of Example 4 achieved a high energy density exceeding that of conventional lithium secondary batteries due to the high hole mobility of the nanosheet film 40, regardless of the material system. As described above, Example 4 demonstrated that the physical secondary battery 100 of this embodiment is an excellent energy storage device that exceeds that of conventional lithium secondary batteries, and is highly versatile, being applicable to a wide range of material systems. It was also confirmed that similar results could be obtained with TiO2, ZrO2, HfO2, Nb2O5, and Ta2O5 in addition to these materials.

[0068] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0069] This application claims priority based on Japanese Patent Application No. 2023-209679, filed with the Japan Patent Office on December 12, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A physical secondary battery comprising: a first electrode; a second electrode; and a p-type semiconductor layer provided between the first electrode and the second electrode.

2. A physical secondary battery according to claim 1, wherein the p-type semiconductor layer is a thin film having a thickness of 100 nm or less.

3. A physical secondary battery according to claim 1, wherein the p-type semiconductor layer is composed of at least one layer of nanosheet film.

4. A physical secondary battery as described in claim 3, wherein the p-type semiconductor layer is composed of a composite nanosheet film formed by arranging a plurality of the nanosheet films without overlapping each other and without gaps.

5. A physical secondary battery according to claim 1, wherein the p-type semiconductor layer is made of zinc oxide (ZnO), cobalt oxide (CoO), nickel oxide (NiO), copper oxide (CuO), tin oxide (SnO), molybdenum sulfide (MoS ２ ), tungsten selenide (WSe ２ ), tin sulfide (SnS), germanium selenide (GeSe), titanium oxide (TiO2), zirconium oxide (ZrO2), hafnium oxide (HfO2), niobium oxide (Nb2O5), and tantalum pentoxide (Ta2O5).

6. A physical secondary battery according to claim 1, wherein the p-type semiconductor layer has a composition formula of ZnO, ZnO 1-ｘ N ｘ , CoO, NiO, Ni 1-ｘ Mn ｘ O, Ni 1-ｘ Fe ｘ O, Ni 1-ｘ Co ｘ O, CuO, MoS ２ , Mo 1-ｘ W ｘ S ２ , WSe ２ , W 1-ｘ M.O. ｘ S e ２ , SnS, TiO ２ , ZrO ２ , HfO ２ , Nb ２ O ５ , Ta ２ O ５ A physical secondary battery that is any one of the above or a mixture or compound of the above.

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