Physical secondary battery

Abstract

A physical secondary battery (100) comprises: a first electrode (10); a second electrode (20); a p-type semiconductor layer (30) provided between the first electrode (10) and the second electrode (20); an n-type semiconductor layer (80) that is provided between the p-type semiconductor layer (30) and the second electrode (20) and that has a thinner film thickness than that of the p-type semiconductor layer (30); and a dielectric layer (90) provided between the p-type semiconductor layer (30) and the n-type semiconductor layer (80), the p-type semiconductor layer (30) having a film thickness of 100 nm or less.

Description

Physical secondary battery

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

[0002] Currently, chemical batteries such as lithium-ion secondary batteries are widely popular. A general lithium-ion secondary battery includes a positive electrode with a lithium-containing transition metal composite oxide as an active material, a negative electrode with a material capable of occluding and releasing lithium ions as an active material, a non-aqueous electrolyte, and a separator (see, for example, JP H5-242911A).

[0003] In recent years, secondary batteries are not only widely used in portable electronic devices, but also closely related to people and widely used in stationary batteries such as electric vehicles, smart grids, humanoid robots, drones, and power load leveling systems. Therefore, the development of a lightweight and small secondary battery with high input / output performance, high capacity, long life, and high safety that exceeds the conventional lithium-ion secondary battery is expected.

[0004] Conventional lithium-ion secondary batteries have limitations in output and capacity per unit weight. In addition, due to their complex structure including a positive electrode, a negative electrode, an electrolyte, and a separator, there are limitations in miniaturization and weight reduction. Furthermore, since lithium-ion secondary batteries involve chemical reactions, they have essential problems such as long charging times, electrolyte degradation, heat generation, lifespan, and safety.

[0005] An object of the present invention is to provide a high-performance secondary battery.

[0006] According to an aspect of the present invention, there is provided a physical secondary battery including a first electrode, a second electrode, a p-type semiconductor layer provided between the first electrode and the second electrode, an n-type semiconductor layer provided between the p-type semiconductor layer and the second electrode and having a thickness thinner than that of the p-type semiconductor layer, and a dielectric layer provided between the p-type semiconductor layer and the n-type semiconductor layer, wherein the p-type semiconductor layer includes a nanosheet film.

[0007] Figure 1 is a schematic diagram of a physical secondary battery according to an embodiment of the present invention. Figure 2 is a schematic diagram of a physical secondary battery according to a modified example of the embodiment of the present invention. Figure 3 is a schematic diagram of a physical secondary battery according to modified example 1 of the embodiment of the present invention, part 1. Figure 4 is a schematic diagram of a physical secondary battery according to modified example 1 of the embodiment of the present invention, part 2. Figure 5A is a schematic plan view of a physical secondary battery according to modified example 2 of the embodiment of the present invention. Figure 5B is a schematic cross-sectional view of a physical secondary battery according to modified example 2 of the embodiment of the present invention.

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

[0009] Figure 1 is a schematic diagram showing the physical secondary battery 100 of this embodiment.

[0010] The physical secondary battery 100 comprises a first electrode 10, a second electrode 20, a p-type semiconductor layer 30 provided between the first electrode 10 and the second electrode 20, an n-type semiconductor layer 80 provided between the p-type semiconductor layer 30 and the second electrode 20 and having a thinner film thickness than the p-type semiconductor layer 30, and a dielectric layer 90 provided between the p-type semiconductor layer 30 and the n-type semiconductor layer 80. Each electrode 10 and 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 it to be charged.

[0011] The p-type semiconductor layer 30 is made of, for example, an oxide-based semiconductor or a chalcogenide-based semiconductor. Examples 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 The p-type semiconductor layer 30 is selected from the group consisting of ), tin sulfide (SnS), and germanium selenide (GeSe). In other words, the p-type semiconductor layer 30 contains at least one of the above substances.

[0012] The p-type semiconductor layer 30 is formed such that its capacity ratio in the physical secondary battery 100 is the largest. The p-type semiconductor layer 30 is constituted by, for example, at least one nanosheet film 40. In other words, the p-type semiconductor layer 30 includes the nanosheet film 40. The nanosheet film 40 is a two-dimensional nanoscale material with a thickness on the order of nanometers, and the horizontal dimension may be several hundred times or more of that. The nanosheet film 40 is formed from, for example, 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 exfoliating from an inorganic layer material. The inorganic layer material can be of various types, but for example, preferably, it is composed of an oxide-based semiconductor or a chalcogenide-based semiconductor, and the composition formulas are 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, GeSe, TiO ２ , ZrO ２ , HfO ２ , Nb ２ O ５ , Ta ２ O ５ are exemplified, and these are used alone or as a mixture or a compound. In other words, the p-type semiconductor layer 30 includes at least one selected from the group consisting of the above.

[0013] The p-type semiconductor layer 30 is constructed by stacking composite nanosheet films 41, for example, which are formed by arranging multiple nanosheet films 40 in a planar manner. In other words, the p-type semiconductor layer 30 includes composite nanosheet films 41. The composite nanosheet film 41 is intended to be a film formed by densely arranging nanosheet films 40, which are single layers of an inorganic layered material, without overlapping. In other words, the composite nanosheet film 41 is formed by arranging multiple nanosheet films 40 without overlapping (specifically, without overlapping in the thickness direction) and without gaps. In Figure 1, the boundaries of nanosheet films 40 arranged in a planar manner in the composite nanosheet film 41 are schematically shown by dotted lines. Note that the p-type semiconductor layer 30 may also be formed from a single layer of composite nanosheet film 41. The p-type semiconductor layer 30 may be a multilayer film formed by stacking composite nanosheet films 41 of the same type (in other words, having the same configuration), or it may be a multilayer film formed by stacking two or more composite nanosheet films 41 of different types (in other words, having different configurations). Furthermore, the p-type semiconductor layer 30 may be formed by stacking nanosheet films 40, or it may be formed by a single layer of nanosheet film 40.

[0014] The first electrode 10 is preferably selected from the group consisting of a transparent oxide conductive film and a metal film. This reduces the contact resistance with the p-type semiconductor layer 30, enabling efficient charging and discharging.

[0015] The transparent oxide conductive film includes, for example, at least one selected from the group consisting of tin-doped indium oxide (ITO), aluminum-doped zinc oxide (AZO), antimond-doped tin oxide (ATO), boron-doped zinc oxide (BZO), and niobium-doped titanium oxide (TNO).

[0016] The metal film includes at least one selected from the group consisting of, for example, gold (Au), platinum (Pt), copper (Cu), and nickel (Ni). Other metals such as silver (Ag), iron (Fe), tin (Sn), zinc (Zn), aluminum (Al), indium (In), and chromium (Cr) may also be used.

[0017] The first electrode 10 is preferably 10 nm or more and 10 μm or less in thickness, but the thickness is not limited to the above. Alternatively, the first electrode 10 made of the above material may be formed in a part of the p-type semiconductor layer 30. In this case, as long as the thickness of the first electrode 10 is within the above range, an insulating substrate or insulating film can be used on which the first electrode 10 and the p-type semiconductor layer 30 made of the above material are patterned and partially arranged. If the first electrode 10 is a thin film on an insulating substrate, it can be partially arranged and formed on the insulating substrate by masking and physical vapor deposition methods such as sputtering, resistance heating deposition, electron beam deposition, molecular beam epitaxy, and ion plating.

[0018] The second electrode 20 may have the same configuration as the first electrode 10. Preferably, the second electrode 20 is made of the same metal as the first electrode 10, and includes at least one selected from the group consisting of, for example, gold (Au), platinum (Pt), copper (Cu), and nickel (Ni). There are no particular restrictions on the thickness of the second electrode 20, but when made of the above metal, the thickness is preferably 5 nm or more and 1 μm or less, but the thickness is not limited to the above. If the thickness of the second electrode 20 is within the above range, the second electrode 20 can be formed by masking a portion of the second electrode 20 on the p-type semiconductor layer 30 in the same way as the first electrode 10, and then by physical vapor deposition or the like.

[0019] 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 during on / off states, and a high capacitance density can be achieved.

[0020] Furthermore, when the p-type semiconductor layer 30 is formed as a nanosheet film 40 (composite nanosheet film 41) as described above, it is more preferable that the film thickness be in the range of 50 nm or less. This allows for a larger current difference during on and off states, and enables the achievement of an even higher capacitance density. Here, it is preferable that the nanosheet film 40 of the p-type semiconductor layer 30 has a film thickness of 0.5 nm or more and 10 nm or less. Within this range, the effect of obtaining both high input / output performance due to high hole mobility and rapid charging performance is achieved. Note that the film thickness of the p-type semiconductor layer 30 and the nanosheet film 40 are not limited to those described above.

[0021] The n-type semiconductor layer 80 includes at least n-type silicon. Silicon is, for example, SiO ｘａ (xa < 2). The n-type semiconductor layer 80 may also contain graphene, various natural graphites, artificial graphite, silicon-based composite materials (silicide), silicon oxide-based materials, titanium alloy-based materials, and various alloy composition materials, either individually or in mixtures. The n-type semiconductor layer 80, like the p-type semiconductor layer 30, is composed of at least one nanosheet film (not shown). Specifically, it is composed of a composite nanosheet film (not shown) in which multiple nanosheet films are arranged in a planar manner, which is then laminated. The nanosheet film is obtained, for example, by exfoliation from an inorganic layered material. Various inorganic layered materials may be used, but preferably, for example, a material with the composition formula Al ２ O3, Si, SiO, SiO ２ , TiO ２ Ti 1-ｘ O ２ Ti3O ７ Ti ４ O ９ Ti ５ O １１ Ti ２ O3, V ２ O5, VO ２ MnO ２ Mn ３ O ７ Fe ２ O ３ Fe ３ O ４ CoO, CoO ２ CuO, ZnO 1-ｘ Ga ２ O3, GeO2, Y2O3, ZrO ２ , Nb ２ O5, Nb ３ O ８ , Nb ６ O １７ MoO ２ MoO3, RuO ２ , PbO, In ２ O3, SnO, HfO ２ , TaO, Ta ２ O5, Ta ３ O ８ Ta ６ O １７ WO３ , W ２ O ７ , IrO ２ , Bi ２ O3, TiNbO ５ , Ti ２ NbO ７ , Ti ５ NbO １４ , LaNb ２ O ７ , Ca ２ Nb ３ O １０ , TiTaO ５ , Ti ２ TaO ７ , Ti ５ TaO １４ , Cs ４-ｘ W １１ O ３６ , Rb ４-ｘ W １１ O ３６ Examples include those represented by these, and in these, a single substance, mixture, or compound is used. In other words, the n-type semiconductor layer 80 contains at least one selected from the group consisting of the above. Note that the n-type semiconductor layer 80 may be formed by laminating nanosheet films or may be composed of a single nanosheet film. The n-type semiconductor layer 80 has a nanosheet film single film thickness of 50 nanometers or less and an overall film thickness thinner than that of the p-type semiconductor layer 30.

[0022] The n-type semiconductor layer 80 is n-doped with, for example, phosphorus oxide, sulfur oxide, or arsenic. Doping with phosphorus oxide or sulfur oxide is performed, for example, by addition and dispersion using a high-shear force disperser. Thereby, the n-type semiconductor layer 80 functions as an n-type semiconductor and can occlude and release ions, holes, and electrons generated in the p-type semiconductor layer 30. Note that the n-type semiconductor layer 80 may be doped with other metal elements. For example, it may be doped with alkali metals such as lithium, sodium, and potassium, or transition metals such as copper, titanium, and zinc.

[0023] Because n-type silicon does not easily function as a heat-generating element, it is less likely to generate heat even if an internal short circuit occurs in the physical secondary battery 100, thereby improving the safety and lifespan of the physical secondary battery 100. In particular, by including silicon, the n-type semiconductor layer 80 can function as an energy storage layer (electron storage layer).

[0024] The dielectric layer 90 contains a ferroelectric material. In this embodiment, the dielectric layer 90 contains, for example, lithium niobate or silicon nitride. Experiments have confirmed that lithium niobate and silicon nitride can be used even at high potentials such as 10V. Furthermore, lithium niobate and silicon nitride are less expensive than other dielectrics. Therefore, by including lithium niobate or silicon nitride in the dielectric layer 90, the physical secondary battery 100 can be used at high potentials, and the cost of the physical secondary battery 100 is reduced. The dielectric layer 90 may also contain other dielectrics such as sodium potassium niobate, bismuth ferrite, sodium niobate, bismuth titanate, and sodium bismuth titanate. The effects of this embodiment can be effectively obtained when the film thickness is thinner than that of the p-type semiconductor layer 30 and the n-type semiconductor layer 80. The dielectric layer 90 may also contain, for example, a perovskite material as the ferroelectric material.

[0025] The dielectric layer 90, like the p-type semiconductor layer 30 and the n-type semiconductor layer 80, is composed of at least one nanosheet film (not shown). Specifically, it is composed of a composite nanosheet film (not shown) in which multiple nanosheet films are arranged in a planar configuration, which is then stacked. The dielectric layer 90 may be composed of stacked nanosheet films or of a single nanosheet film.

[0026] The methods for forming the inorganic layered material, the first electrode 10, and the second electrode 20 are as described above, so we will omit further explanation.

[0027] The p-type semiconductor layer 30 formed from the nanosheet film 40 (composite nanosheet film 41) can be formed in the following three steps: Step 1: Prepare a colloidal dispersion in which the nanosheet film components are dispersed in a dispersion medium. Step 2: Using the colloidal dispersion, form a laminate (p-type semiconductor layer 30) of the nanosheet film 40 (composite nanosheet film 41), which is a single layer of nanosheets, on the first electrode 10. Step 3: Form a second electrode 20 on the laminate of the nanosheet film 40 (composite nanosheet film 41).

[0028] Each step will be described in detail. In step 1, the inorganic layered material powder described above is placed in an aprotic polar solvent, such as methyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), or formamide, and subjected to sonication (treatment frequency: 20 kHz - 1 MHz, treatment time: 20 minutes - 3 hours). This causes the layers constituting the layered structure to be peeled off into individual layers, yielding a colloidal dispersion in which the nanosheet film components are dispersed. Subsequently, the polar solvent is evaporated and the dispersion is carried out in pure water to obtain a water-soluble colloidal dispersion.

[0029] In step 2, a method selected from the group consisting of the Langmuir-Blodgett method (LB), the layer-by-layer method (LBL), the spin coating method, the drop coating method, the slit coating method, the bar coating method, and the dip coating method is preferably employed to form the nanosheet film 40 (composite nanosheet film 41) and the laminate thereof.

[0030] The LB method is a technique for forming a nanosheet film 40 (composite nanosheet film 41) using surface pressure. A colloidal dispersion of nanosheet film components is spread into a trough (water tank) in which an insulating substrate or insulating film is immersed and a first electrode 10 is provided, 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 first electrode 10. By repeating this process, a laminate of nanosheet films 40 is formed on the first electrode 10.

[0031] With the LB method, a single layer of nanosheet film 40 is formed at the gas-liquid interface on the surface of the developing solution, with the nanosheet films 40 accumulating in the planar direction without overlapping each other. Therefore, an extremely homogeneous and high-quality nanosheet film 40 can be formed on the first electrode 10.

[0032] The LBL method, also known as the alternating adsorption method, is a technique for forming nanosheet films 40 (composite nanosheet films 41) using electrostatic interactions. Counterions (e.g., cationic polymers) are applied to an insulating substrate or insulating film on which a first electrode 10 is placed, and then a colloidal dispersion is applied. This causes electrostatic interactions between the counterions and the nanosheets, resulting in strong bonding and the formation of a nanosheet film 40. These steps are repeated until the desired thickness is reached, 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.

[0033] 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 equipped with a first electrode 10 that rotates at high speed, and a uniform nanosheet single-layer film, the nanosheet film 40 (composite nanosheet film 41), is obtained by centrifugal force. This process is repeated to obtain a laminate of nanosheet films 40. Using the spin coating method, a laminate of nanosheet films 40 can be obtained relatively easily.

[0034] The drop method involves dropping a colloidal dispersion onto an insulating substrate or insulating film on which the first electrode 10 is placed, using a pipette or the like, and then drying it. This yields a nanosheet film 40 (composite nanosheet film 41). By repeating this process, a laminate of nanosheet films 40 can be obtained.

[0035] The dip-coating method involves immersing the first electrode 10 on an insulating film or on an insulating film in a colloidal dispersion, then removing and drying it. In this case as well, a nanosheet film 40 (composite nanosheet film 41) can be obtained, and by repeating this process, a laminate of nanosheet films 40 can be obtained.

[0036] In bar coating and slit coating methods, colloidal dispersions can be used in existing methods.

[0037] The method for forming the n-type semiconductor layer 80 and dielectric layer 90 from a nanosheet film (composite nanosheet film) is the same as for the p-type semiconductor layer 30, so a detailed explanation will be omitted. Furthermore, the n-type semiconductor layer 80 and dielectric layer 90 are not limited to those formed from nanosheet films or composite nanosheet films. The n-type semiconductor layer 80 and dielectric layer 90 can be formed by various methods, for example, thin film n-type semiconductor layers 80 and dielectric layers 90 can be formed by physical vapor deposition methods such as sputtering, resistance heating deposition, electron beam deposition, molecular beam epitaxy, and ion plating, or by chemical vapor deposition methods such as thermal CVD, photo-CVD, plasma CVD, atomic layer deposition, and metal-organic vapor deposition.

[0038] By the method described above, the physical secondary battery 100 of this embodiment can be obtained.

[0039] The physical secondary battery 100 of this embodiment is an all-solid-state secondary battery that differs completely in principle and structure from conventional chemical batteries such as lithium-ion secondary batteries. It has a structure consisting of three layers: a p-type semiconductor layer 30 containing a nanosheet film 40, an n-type semiconductor layer 80, and a dielectric layer 90, which functions as an energy storage mechanism. By inserting a large current with one of the first electrode 10 (current collector) and the second electrode 20 (current collector) as positive and the other as negative, a polarization phenomenon (charge accumulation) is induced in the n-type semiconductor layer 80, allowing for energy storage. Specifically, during charging, the high-potential terminal of the external power supply is electrically connected to one side of the p-type semiconductor layer 30, and the low-potential terminal is electrically connected to the opposite side of the p-type semiconductor layer 30. This causes holes to polarize in the p-type semiconductor layer 30 and charges to polarize in the n-type semiconductor layer 80 around the dielectric layer 90, thereby storing energy. During discharge, holes move to the opposite side, and further, electricity flows as charges are released into the external circuit. By utilizing this polarization phenomenon (Hall migration) and charging with a large current, preferably between 100C and 1000C, it is possible to achieve both high input / output performance and high capacity that surpass lithium secondary batteries, while also achieving shorter charging times and high cycle stability. Furthermore, in this embodiment, the physical secondary battery 100 can minimize the ineffective storage area due to the nanosheet-like p-type semiconductor layer 30 and n-type semiconductor layer 80, thereby realizing highly efficient energy storage. Moreover, the charge storage area due to polarization can be expanded, and the energy storage layer can be reliably secured compared to when the physical secondary battery 100 does not have an n-type semiconductor layer 80 and a dielectric layer 90, thus further improving capacity performance and input / output performance.

[0040] Furthermore, the physical secondary battery 100 of this embodiment utilizes hole movement, which has higher mobility, rather than ion movement, which is used in conventional lithium-ion secondary batteries. This results in the combined effect of high input / output performance and rapid charging performance due to higher hole mobility than conventional lithium-ion secondary batteries. Moreover, by utilizing the nanosheet film 40, internal resistance is reduced and even higher hole mobility can be achieved, thus enabling further improvements in high output performance, high capacity, and rapid charging performance.

[0041] Furthermore, since the physical secondary battery 100 of this embodiment does not involve chemical reactions during charging and discharging, it offers the advantages of rapid charging, high output, high capacity, and long lifespan, along with high safety.

[0042] As described above, the physical secondary battery 100 of this embodiment operates on the principle of movement of positive charge carriers (holes), and can therefore be said to be a battery based on the principle of a semiconductor battery. In fact, the physical secondary battery 100 has a simple structure consisting only of solid materials, a p-type semiconductor layer 30, an n-type semiconductor layer 80, and a dielectric layer 90, and is therefore advantageous in terms of manufacturing, cost, and lifespan, and is also easy to make lighter and smaller.

[0043] Furthermore, in conventional lithium-ion secondary batteries, the positive and negative electrodes are formed by mixing and coating materials, which limits the miniaturization and thinning of the first electrode 10 and the second electrode 20, thus limiting the overall miniaturization of the battery. In contrast, the physical secondary battery 100 of this embodiment is formed from a p-type semiconductor layer 30 with a thickness of 100 nm or less, an n-type semiconductor layer 80 thinner than the p-type semiconductor layer 30, and a dielectric layer 90. Therefore, even a small p-type semiconductor layer 30, for example, measuring 2 mm square, can be easily manufactured, allowing the physical secondary battery 100 to be smaller than conventional lithium-ion secondary batteries. As a result, the physical secondary battery 100 of this embodiment can be formed into a small chip shape and installed on the electronic circuit board of electronic equipment or safely placed in small spaces such as cardiac pacemakers.

[0044] Furthermore, the physical secondary battery 100 of this embodiment can be installed on the electronic circuit board of an electronic device and function as a power source or auxiliary power source for the electronic device. For example, by installing the physical secondary battery 100 on the electronic circuit board of a personal computer as an electronic device and allowing it to function as an auxiliary power source, it is possible to retain the contents of volatile memory and mitigate shocks to electronic components when the power supply from the main power source is interrupted due to a power outage or the like. Also, even when the main power source is off, power can be supplied from the physical secondary battery 100 to the volatile memory and its contents can be retained. In addition, the physical secondary battery 100 can be installed on the electronic circuit board of a pacemaker as an electronic device and function as a main power source. The physical secondary battery 100 does not involve chemical reactions during operation and therefore has high safety. Furthermore, since the physical secondary battery 100 is a rechargeable secondary battery, rather than the non-rechargeable primary battery used in conventional pacemakers, it is also suitable as a main power source for pacemakers.

[0045] Furthermore, as shown in Figure 2, the physical secondary battery 100 of this embodiment may have a p-type semiconductor layer 30, an n-type semiconductor layer 80, and a dielectric layer 90 formed inside a case 60 and provided on an electronic substrate 51. Note that the nanosheet film 40 and the composite nanosheet film 41 are not shown in Figure 2. The case 60 may be formed from a conductive material such as copper, or it may be formed by arranging conductors inside a ceramic container. The case 60 has a concave main body portion 61 mounted on the electronic substrate 51 and a lid portion 62 that closes the opening of the main body portion 61. An O-ring 65, which serves as a sealing member and is made of an insulator such as insulating rubber, is provided between the main body portion 61 and the lid portion 62 to prevent electrical connection between the main body portion 61 and the lid portion 62.

[0046] The first electrode 10 is electrically connected to the lid 62 of the case 60 via a current-carrying part 70 such as a lead wire, wire, or conductive paste. The second electrode 20 is provided on the main body 61 of the case 60. As a result, the second electrode 20 is electrically connected to the main body 61, and the first electrode 10 is electrically connected to the lid 62. With the main body 61 and lid 62 of the case 60 electrically connected to the circuit of the electronic circuit board 51, the physical secondary battery 100 functions as a power source or auxiliary power source for electronic equipment.

[0047] Thus, the physical secondary battery 100 is easily miniaturized and lightweight, and can be installed on the electronic circuit board 51 of an electronic device and used as a power source or auxiliary power source. Furthermore, since the p-type semiconductor layer 30, n-type semiconductor layer 80, and dielectric layer 90 of the physical secondary battery 100 do not undergo chemical changes during charging and discharging, it does not expand or contract like conventional lithium-ion secondary batteries, and can maintain a small chip-like shape. In addition, since the p-type semiconductor layer 30, n-type semiconductor layer 80, and dielectric layer 90 of the physical secondary battery 100 are housed in the case 60, secondary safety effects such as preventing deterioration of the physical secondary battery 100 due to heat from the electronic device and preventing leakage current when the electronic device is submerged in water are achieved.

[0048] In the configuration shown in Figure 2, the p-type semiconductor layer 30 of the physical secondary battery 100 may be electrically connected to the side wall portion 61b of the main body portion 61 of the case 60 via the current-carrying portion 70. In this case, for example, an O-ring made of an insulator can be provided between the bottom plate 61a and the side wall portion 61b of the main body portion 61 to prevent electrical connection between the bottom plate 61a and the side wall portion 61b. The case 60 may also be made of an insulating material such as silica. For example, this configuration corresponds to the configuration shown in Figure 1 when placed in a cylindrical can. In this case, for example, the p-type semiconductor layer 30 can be electrically connected to the outside of the case 60 by forming a through hole in the case 60 and providing the current-carrying portion 70 in the through hole.

[0049] Furthermore, in the configuration shown in Figure 2, the p-type semiconductor layer 30 may be electrically connected to the lid portion 62 of the case 60 via the energizing portion 70, and the n-type semiconductor layer 80 may be provided on the main body portion 61 of the case 60. In this case, the lid portion 62, which is directly electrically connected to the p-type semiconductor layer 30, corresponds to the first electrode 10, and the main body portion 61, which is directly electrically connected to the n-type semiconductor layer 80, corresponds to the second electrode 20. In this configuration, since only the p-type semiconductor layer 30, the n-type semiconductor layer 80, and the dielectric layer 90 are provided on the case 60, a complex configuration is unnecessary.

[0050] Alternatively, the p-type semiconductor layer 30, n-type semiconductor layer 80, and dielectric layer 90 of the physical secondary battery 100 may be formed on an insulating material such as a resin film or silica, on which some conductive material is provided in a dot-like manner on the front and back surfaces, and then unitized and housed in the case 60. Specifically, the physical secondary battery 100 is housed in the case 60 with the insulating material mounted on the bottom plate 61a of the main body portion 61 of the case 60. The negative electrode terminal may be electrically connected to the main body portion 61 via an energizing portion provided in a through-hole in the insulating material. Note that the portion on which some conductive material is formed may be linear rather than dot-like; in this case, the through-hole and energizing portion become unnecessary by forming the linear conductive material so as to penetrate the insulating material in the thickness direction.

[0051] Furthermore, the physical secondary battery 100 may be provided on the electronic circuit board 51 of the electronic device without going through the case 60. In other words, the physical secondary battery 100 may be provided on the electronic circuit board 51 of the electronic device via a component, or it may be provided directly on the electronic circuit board 51 of the electronic device.

[0052] Furthermore, the physical secondary battery 100 may also include a coil (not shown) for wireless power supply that is electrically connected to the first electrode 10 and the second electrode 20, and power may be charged via the coil. This allows the physical secondary battery 100 to be charged non-contact even when it is installed on the electronic circuit board 51 of an electronic device. In particular, when the physical secondary battery 100 is used as the main power source for a pacemaker, it can be charged by wireless power supply before it runs out of power. As a result, the physical secondary battery 100 used as the main power source for a pacemaker is rechargeable because it is a secondary battery and can be charged from outside the body by wireless power supply, eliminating the need for battery replacement by surgery as was previously performed, and allowing it to be used semi-permanently.

[0053] The following describes an embodiment of the physical secondary battery 100 according to this embodiment. However, the present invention is not limited to the following embodiment.

[0054] <Example> In this example, a physical secondary battery 100 was manufactured using a nickel oxide nanosheet (0.01 μm) as the p-type semiconductor layer 30, a lithium niobate nanosheet (0.003 μm), which is a ferroelectric, as the dielectric layer 90, and an n-type silicon nanosheet (0.005 μm), which is an n-type semiconductor, as the n-type semiconductor layer 80.

[0055] Specifically, after exfoliating nickel hydroxide, a green sol solution (colloidal dispersion) containing rectangular nickel oxide nanosheets with a thickness of approximately 1 nm and a width of approximately 1 μm was prepared by heating and dehydration. Using this colloidal dispersion, a laminate (p-type semiconductor layer 30) of composite nanosheet films (thickness 0.002 μm) formed by multiple nanosheet monolayer films was created on an ITO substrate, which served as the first electrode 10, by the LB method. The ITO substrate was surface-cleaned by ultraviolet irradiation in an ozone atmosphere.

[0056] After thoroughly cleaning the LB trough with acetone, a colloidal dispersion containing nickel oxide nanosheet film material was spread onto the trough, and the surface was allowed to stabilize and the temperature of the lower layer liquid to become constant for 30 minutes. Then, the ITO substrate was set in the LB film deposition apparatus, and the following series of operations constituted one cycle, which was repeated 10 times to form a laminate (p-type semiconductor layer 30) consisting of multiple nanosheet monolayer films. (1) By moving the barrier at a compression speed of 0.5 mm / min and compressing the surface, the nanosheet films dispersed on the gas-liquid interface were gathered together, and after reaching a constant pressure, it was left to stand for 30 minutes. (2) By vertically pulling up the ITO substrate at a pulling speed of 0.8 mm / min and attaching the nanosheet films gathered on the gas-liquid interface to the substrate, a composite nanosheet film (thickness 0.002 μm) was formed in which the nanosheet films were densely arranged without overlapping. (3) Using the above method, a lithium niobate nanosheet film (dielectric layer 90) was formed on the nickel oxide nanosheet film (p-type semiconductor layer 30) by similarly forming a lithium niobate film material-containing colloidal dispersion, and further, an n-type silicon nanosheet film (n-type semiconductor layer 80) was formed on the dielectric layer 90.

[0057] The resulting laminate is exposed to ultraviolet light (wavelength: 200-300 nm, intensity: 1 mW / cm²) using a xenon light source. ２The material was irradiated with 24 hours of light to decompose and remove organic matter. Next, a gold electrode was deposited onto the laminate as the second electrode 20 using a vacuum deposition apparatus (SVC-700, manufactured by Sanyu Electronics Co., Ltd.) to produce the physical secondary battery 100 of this embodiment. The p-type semiconductor layer 30 side was used as the positive electrode and the n-type semiconductor layer 80 side as the negative electrode, and it was charged at 1000C.

[0058] <Comparative Example 1> In Comparative Example 1, a stacked lithium-ion secondary battery was prepared using lithium nickel-manganese-cobalt oxide BC-618 manufactured by Sumitomo 3M Limited as a conventional lithium-ion secondary battery.

[0059] <Comparative Example 2> In Comparative Example 2, a physical secondary battery was manufactured that did not include an n-type semiconductor layer 80 and a dielectric layer 90, and in which the p-type semiconductor layer 30 (0.01 μm) was formed from nickel oxide nanosheets.

[0060] After exfoliating nickel hydroxide, a green sol solution (colloidal dispersion) containing rectangular nickel oxide nanosheets with a thickness of approximately 1 nm and a width of approximately 1 μm was prepared by heating and dehydration. Using this colloidal dispersion, a laminate of composite nanosheet films 41 (thickness 0.002 μm) formed by multiple nanosheet monolayer films (nanosheet films 40) was formed on an ITO substrate as the first electrode 10 by the LB method. The ITO substrate was surface-cleaned by ultraviolet irradiation in an ozone atmosphere.

[0061] After thoroughly cleaning the LB trough with acetone, a colloidal dispersion containing nickel oxide nanosheet film material was spread onto the trough, and the surface was allowed to stabilize and the temperature of the lower layer liquid to become constant for 30 minutes. Then, the ITO substrate was set in the LB film deposition apparatus, and the following series of operations constituted one cycle, which was repeated 10 times to form a laminate (composite nanosheet film) consisting of multiple nanosheet films. (1) By moving the barrier at a compression speed of 0.5 mm / min and compressing the surface, the nanosheet films 40 dispersed on the gas-liquid interface were gathered together, and after reaching a constant pressure, they were left to stand for 30 minutes. (2) By vertically pulling up the ITO substrate at a pulling speed of 0.8 mm / min and attaching the nanosheet films 40 gathered on the gas-liquid interface to the substrate, a composite nanosheet film 41 (thickness 0.002 μm) was formed in which the nanosheet films 40 were densely arranged without overlapping.

[0062] The resulting laminate is exposed to ultraviolet light (wavelength: 200-300 nm, intensity: 1 mW / cm²) using a xenon light source. ２ The material was irradiated with ) for 24 hours to decompose and remove organic matter. Next, a gold electrode was deposited on the laminate as the second electrode 20 using a vacuum deposition apparatus (SVC-700, manufactured by Sanyu Electronics Co., Ltd.) to produce the physical secondary battery of Comparative Example 2. This was then charged at 1000C with one side as the positive electrode and the opposite side as the negative electrode.

[0063] The physical secondary battery 100 of the example manufactured as described above, and the secondary batteries of Comparative Examples 1 and 2 were evaluated using the method shown below.

[0064] (Initial Battery Capacity Evaluation) The capacity performance of secondary batteries was evaluated in the potential ranges of 2V-4.3V and 2-6V. For this study, a rectangular battery case was used, and the batteries were stacked. Furthermore, the 100C / 1C discharge capacity ratio was measured to evaluate high-power performance. Similarly, the 100C / 1C charge capacity ratio was measured to evaluate input performance and rapid charging capability.

[0065] (Nail Penetration Test) A fully charged secondary battery was penetrated by a 2.7 mm diameter iron nail at a speed of 5 mm / second under normal temperature conditions. The heat generation and appearance were observed. The results are shown in Table 1 below. In Table 1, secondary batteries that did not show any change in temperature or appearance are indicated as "OK," and secondary batteries that showed a change in temperature or appearance are indicated as "NG."

[0066] (Overcharge Test) The batteries were kept at a charge level of 200% and the current was maintained for 15 minutes or more to determine if any changes in appearance occurred. The results are shown in Table 1 below. In Table 1, batteries that did not show any abnormalities are indicated as "OK," and batteries that showed changes (such as swelling or rupture) are indicated as "NG."

[0067] (Life Test) For the secondary batteries of the examples and comparative examples, with a specified potential range of 1V-5V, charging was performed at 1C / 5V at 25°C, followed by 3000 cycles and 10,000 cycles of 1C / 1V discharge, and the capacity degradation was compared to the initial capacity.

[0068] Table 1 shows the evaluation results of the physical secondary battery 100 of this embodiment and the secondary batteries of Comparative Examples 1 and 2.

[0069] As shown in Table 1, the physical secondary battery 100 of the embodiment exhibited excellent charging characteristics even at high charging rates, confirming that rapid charging was achieved. Furthermore, unlike the conventional stacked lithium-ion secondary battery of Comparative Example 1, it exhibited excellent discharge characteristics even at high rates, confirming that it possessed both high output and high capacity characteristics. Moreover, it is an all-solid-state secondary battery with a completely different principle and structure from chemical batteries such as conventional lithium-ion secondary batteries, and it was confirmed that it also possesses the high safety characteristic of all-solid-state batteries. In summary, the embodiment demonstrates that the physical secondary battery 100 of this embodiment is a superior energy storage device that surpasses conventional lithium-ion secondary batteries.

[0070] Furthermore, as shown in Table 1, it was confirmed that the physical secondary battery 100 of the example performed better in initial battery capacity evaluation and life test results than the physical secondary battery of Comparative Example 2, which does not have an n-type semiconductor layer 80 and a dielectric layer 90. In addition, it was confirmed that the physical secondary battery 100 of the example performed without problems in nail puncture tests and overcharge tests.

[0071] Next, modifications of this embodiment will be described. The following modifications are also within the scope of the present invention, and it is possible to combine the configurations shown in the modifications with the configurations described in the above embodiments, or to combine the configurations described in the following different modifications.

[0072] <Modification 1> In the above embodiment, the physical secondary battery 100 comprises one p-type semiconductor layer 30, one n-type semiconductor layer 80, and one dielectric layer 90. However, it is not limited to this, and as shown in Figure 3, the physical secondary battery 200 may be configured such that multiple units 95, each formed by three layers of a p-type semiconductor layer 30, a dielectric layer 90, and an n-type semiconductor layer 80, are stacked, and at least a portion of the p-type semiconductor layer 30 and n-type semiconductor layer 80 of adjacent units 95 are in contact. Note that in Figure 3, the nanosheet film 40 and the composite nanosheet film 41 are not shown. In the physical secondary battery 200, electrons and holes exist polarized in the p-type semiconductor layer 30 and n-type semiconductor layer 80 with the dielectric layer 90 as the center. Therefore, if the p-type semiconductor layer 30 is thicker than the n-type semiconductor layer 80, it is possible to prevent holes from existing at the n-type semiconductor layer 80 side of adjacent units 95 in the p-type semiconductor layer 30, so that multiple units 95 can be stacked without short circuits. This configuration allows for further improvement in the performance of the physical secondary battery 200.

[0073] Furthermore, as shown in Figure 4, the dielectric layers 90 of multiple units 95 may be formed connected to each other. The n-type semiconductor layer 80 and the dielectric layer 90 are formed over a larger area than the p-type semiconductor layer 30, and connecting members 92 are provided at the ends of the dielectric layer 90, extending in the stacking direction and contacting the dielectric layers 90 of each of the multiple units 95. The connecting members 92 are made of a conductive material, and the dielectric layers 90 of the multiple units 95 are electrically connected by the connecting members 92. The n-type semiconductor layer 80 does not contact the connecting members 92, and an insulating member 91, for example made of resin, is provided between the p-type semiconductor layer 30 and the connecting members 92, so that the physical secondary battery 200 does not short circuit. In this configuration, the charge storage layers become a parallel circuit, and the impedance (resistance) within the physical secondary battery 200 decreases as the number of stacked units 95 increases. Therefore, because the IR drop is reduced, the performance of the physical secondary battery 200 improves more than the sum of the capacities gained by stacking multiple units 95.

[0074] <Modification 2> The physical secondary battery 100 of the above embodiment comprises one p-type semiconductor layer 30, one n-type semiconductor layer 80, and one dielectric layer 90. However, it is not limited to this, and as shown in Figure 5, the physical secondary battery 300 may have a plurality of units 95 similar to the physical secondary battery 200 and be formed in a cell shape. Figure 5(a) is a plan view showing a plurality of cells (units 95) of the physical secondary battery 300, and Figure 5(b) is a cross-sectional view of one cell of the physical secondary battery 300. Two units 95 are stacked in one cell, and an insulating film 93 is provided between the two units 95. The first electrode 210 and the second electrode 220 are formed in a conductive paste form. In the physical secondary battery 300, the first electrode 210 and the second electrode 220 of the upper unit 95 of adjacent cells are electrically connected by a conductive member 94 such as a cable or terminal, and the first electrode 210 and the second electrode 220 of the lower unit 95 of adjacent cells are electrically connected by another conductive member 94. Even with this configuration, the performance of the physical secondary battery 300 is improved, similar to the modification 1 described above. The physical secondary battery 100 in the above embodiment may also be formed in a cell shape, similar to the physical secondary battery 300.

[0075] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0076] This application claims priority under Japanese Patent Application No. 2024-173287, filed with the Japan Patent Office on 2 October 2024, and all contents of that application are incorporated herein by reference.

Claims

1. A physical secondary battery comprising: a first electrode; a second electrode; a p-type semiconductor layer provided between the first electrode and the second electrode; an n-type semiconductor layer provided between the p-type semiconductor layer and the second electrode and having a thickness thinner than the p-type semiconductor layer; and a dielectric layer provided between the p-type semiconductor layer and the n-type semiconductor layer, wherein the p-type semiconductor layer includes a nanosheet film.

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

3. A physical secondary battery according to claim 1, wherein a plurality of units formed by the three layers of the p-type semiconductor layer, the dielectric layer, and the n-type semiconductor layer are stacked, and at least a portion of the p-type semiconductor layer and the n-type semiconductor layer of adjacent units are in contact.

4. A physical secondary battery according to claim 1, wherein the dielectric layers of a plurality of the units are electrically connected to each other.

5. The physical secondary battery according to claim 1, wherein the p-type semiconductor layer is 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, GeSe, TiO ２ , ZrO ２ , HfO ２ , Nb ２ O ５ , and Ta ２ O ５ and includes at least one selected from the group consisting of.

6. A physical secondary battery according to claim 1, wherein the n-type semiconductor layer is Al ２ O3, Si, SiO, SiO ２ , TiO ２ Ti 1-ｘ O ２ Ti3O ７ Ti ４ O ９ Ti ５ O １１ Ti ２ O3, V ２ O5, VO ２ MnO ２ Mn ３ O ７ Fe ２ O ３ Fe ３ O ４ CoO, CoO ２ CuO, ZnO 1-ｘ Ga ２ O3, GeO2, Y2O3, ZrO ２ , Nb ２ O5, Nb ３ O ８ , Nb ６ O １７ MoO ２ MoO3, RuO ２ , PbO, In ２ O3, SnO, HfO ２ , TaO, Ta ２ O5, Ta ３ O ８ Ta ６ O １７ WO ３ , W ２ O ７ IrO ２ , Bi ２ O3, TiNbO ５ Ti ２ NboO ７ Ti ５ NboO １４ LaNb ２ O ７ Ca ２ Nb ３ O １０ , TiTaO ５ Ti ２ TaO ７ Ti ５ TaO １４ , Cs ４-ｘ W １１ O ３６ and Rb ４-ｘ W １１ O ３６ A physical secondary battery comprising at least one selected from the group consisting of the following.

7. A physical secondary battery according to claim 1, wherein the dielectric layer includes a ferroelectric material and is thinner than the p-type semiconductor layer and the n-type semiconductor layer.

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