Patent Application
20200006763
The embodiments described herein relate to an electricity storage device.
As conventional electricity storage devices, there have been proposed secondary batteries, in which a first electrode/an insulating material/an n type oxide semiconductor layer/a p type oxide semiconductor layer/a second electrode are layered, since electrolytic solutions and rare elements are not used and thinning thereof can be realized.
Moreover, as a structure similar to such secondary batteries, there have been proposed secondary batteries including: a positive electrode including a positive-electrode active material layer containing a nickel oxide or the like as a positive-electrode active material; a solid electrolyte having an aqueous porous structure; and a negative electrode including a negative-electrode active material layer containing a titanium oxide or the like as a negative-electrode active material.
Moreover, there have also been proposed electricity storage devices having a structure in which an n type semiconductor layer, a charge layer, an insulation layer, and a p type semiconductor layer are layered, and electrodes are formed at upper and lower sides thereof.
The embodiments provide an electricity storage device capable of increasing an electricity storage capacity per unit volume (weight).
According to one aspect of the embodiments, there is provided an electricity storage device comprising: a first oxide semiconductor layer having a first conductivity-type first oxide semiconductor; a first charge layer disposed on the first oxide semiconductor layer, the first charge layer composed by comprising a first insulating material and a second oxide semiconductor, the second oxide semiconductor having the first conductivity-type; and a third oxide semiconductor layer disposed on the first charge layer, wherein the third oxide semiconductor layer has hydrogen and a second conductivity-type third oxide semiconductor, and a percentage of the hydrogen with respect to a metal constituting the third oxide semiconductor is equal to or greater than 40%.
According to the embodiments, there can be provided the electricity storage device capable of increasing the electricity storage capacity per unit volume (weight).
Next, the embodiments will be described with reference to drawings. In the description of the following drawings, the identical or similar reference sign is attached to the identical or similar part. However, it should be noted that the drawings are schematic and therefore the relation between thickness and the plane size and the ratio of the thickness differs from an actual thing. Therefore, detailed thickness and size should be determined in consideration of the following explanation. Of course, the part from which the relation and ratio of a mutual size differ also in mutually drawings is included.
Moreover, the embodiments shown hereinafter exemplify the apparatus and method for materializing the technical idea; and the embodiments do not specify the material, shape, structure, placement, etc. of each component part as the following. The embodiments may be changed without departing from the spirit or scope of claims.
In explanation of following embodiments, a first conductivity type means an n type and a second conductivity type means a p type opposite to the first conductivity type, for example. The first conductivity-type first oxide semiconductor 14 means an oxide semiconductor layer having a first conductivity-type first oxide semiconductor. The second conductivity-type third oxide semiconductor layer 24 means an oxide semiconductor layer having a second conductivity-type third oxide semiconductor. The same applies hereafter.
As shown in
Moreover, in the electricity storage device 30 according to the embodiments, the third oxide semiconductor layer 24 may include a nickel oxide (NiOyHx) containing hydrogen, a value of a hydrogen composition ratio x may be equal to or greater than 0.35, and a value of an oxygen composition ratio y may be selected value.
Moreover, the electricity storage device 30 may include a second charge layer 18 disposed between the first charge layer 16 and the third oxide semiconductor layer 24.
Moreover, the second charge layer 18 may include a second insulating material.
Moreover, the third oxide semiconductor may include NiO.
Alternatively, the second charge layer 18 may include the second insulating material and a conductivity adjusting material.
Moreover, the second oxide semiconductor may include at least one oxide selected from the group consist of an oxide of Ti, an oxide of Sn, an oxide of Zn, and an oxide of Mg.
Moreover, the conductivity adjusting material may include a first conductivity-type semiconductor or a metallic oxide.
Alternatively, the conductivity adjusting material may include at least one oxide selected from the group of consisting of an oxide of Sn, an oxide of Zn, an oxide of Ti, and an oxide of Nb.
Moreover, the second insulating material may include SiOx, and the conductivity adjusting material may include SnOx.
Alternatively, the second insulating material may include SiOx formed as a film from silicone oil.
Moreover, the first insulating material may include SiOx and the second oxide semiconductor may include TiOx.
Furthermore, the third oxide semiconductor layer may include a metal different from the third oxide semiconductor. In this case, such a metal may include lithium or cobalt.
Moreover, in the electricity storage device 30 according to the embodiments, a thickness of the third oxide semiconductor layer 24 may be increased. An amount of hydrogen storage of the third oxide semiconductor layer 24 can be increased and an amount of hydrogen storage to the first charge layer 16 can be increased by increasing the thickness of the third oxide semiconductor layer 24.
Moreover, a thickness of the first charge layer 16 may be increased, in the electricity storage device 30 according to the embodiments. An amount of hydrogen storage to the first charge layer 16 can be increased by increasing the thickness of the first charge layer 16.
In the electricity storage device 30 according to the embodiments, a hydrogen concentration of the third oxide semiconductor layer 24 may be increased and the first charge layer 16 may also be thickly, in order to obtain enough electricity storage capacity formed.
Alternatively, the first charge layer 16 may include a structure of at least two-layer of which compositions are different from each other. The first charge layer 16 may be formed by including a silicon oxide (SiOx)/a titanium oxide (TiOx), for example. Specifically, the first charge layer 16 may be formed by including a layered structure of SiOx/TiOx, or may be formed by including a particulate bonding structure in which the periphery of particle-shaped TiOx is covered with SiOx. Alternatively, the first charge layer 16 may include a structure into which TiOx and SiOx are mixed, or a structure in which TiOx is wrapped in a silicon oxide. In the above description, the compositions of the titanium oxide and the silicon oxide are respectively not limited to TiOx and SiOx, but may include a structure in which the composition ratio x, of TiOx and/or SiOx is changed.
Moreover, the n type oxide semiconductor may be an oxide of titanium (Ti), tin (Sn), zinc (Zn), or magnesium (Mg). Accordingly, the first charge layer 16 may be a layered structure of SiOx and an oxide of Ti, Sn, Zn, or Mg, or may be formed of a particulate bonding structure in which the periphery of an oxide of particle-shaped Ti, Sn, Zn, or Mg is covered with SiOx. Alternatively, the first charge layer 16 may include a configuration in which a molecule or molecular group of SiOx and an oxide of Ti, Sn, Zn, or Mg is surrounded by SiOx (amorphous).
Alternatively, the first charge layer 16 may include a porous structure.
First Charge Layer
The first charge layer 16 is a layer for storing hydrogen which is generated at the time of charging. In the first charge layer 16, a reaction of M+H2O+e−→MH+OH− progresses at the time of charging, and a reaction of MH+OH−→M+H2O+e− progresses at the time of discharging. If the first charge layer 16 is made porous, efficiency of storing the hydrogen can be increased. Moreover, the hydrogen storage and electrical conductivity can be optimized if the first charge layer 16 is formed as a plurality of layers. It can be optimized by forming the second oxide semiconductor by using an oxide of Ti, Sn, Zn or Mg.
Second Charge Layer
The second charge layer 18 is a buffer layer for adjusting movement of H+ and electrons (e−).
P Type Oxide Semiconductor Layer
The oxide semiconductor layer 24 constitutes a pn junction with respect to the n type semiconductor of the first charge layer 16 (second oxide semiconductor), and can suppress an electric charge leak at the time of charging. It is possible to increase a supply amount of the hydrogen to the first charge layer 16 by forming the p type oxide semiconductor layer 24 as a nickel oxide (NiOyHx) containing hydrogen.
N Type Oxide Semiconductor Layer
As shown in
Manufacturing Method
A manufacturing method of the electricity storage device 30 according to the embodiments includes: forming a first conductivity-type first oxide semiconductor 14; forming a first charge layer 16 composed by including a first insulating material and a first conductivity-type second oxide semiconductor on the first oxide semiconductor layer 14; forming a second charge layer 18 on the first charge layer 16; and forming a third oxide semiconductor layer 24 on the second charge layer 18 by a sputtering deposition method.
In the embodiments, in the forming of the third oxide semiconductor layer 24, metallic nickel Ni may be used as a target material at the time of the sputtering, and vapor and water may be supplied in the chamber, and a flow rate of sputtering may be increased.
Moreover, in the forming of the third oxide semiconductor layer 24, Ni atoms are excited from the target due to an ion bombardment with argon ions Ar+, and the excited Ni atoms react with the hydrogen and oxygen in the chamber and undergo a sputter deposition reaction, and thereby the third oxide semiconductor layer 24 containing hydrogen may be deposited thereon.
n Type Oxide Semiconductor Layer 14
A TiOx layer is formed as a film on the first electrode 12 which constitutes a lower electrode, for example by a sputtering deposition method. In this case, Ti or TiOx can be used as a target. The layer thickness of the n type oxide semiconductor layer 14 is approximately 50 nm to 200 nm, for example. In addition, a tungsten (W) electrode or the like can be applied to the first electrode 12, for example.
First Charge Layer 16
A chemical solution is formed by stirring titanium fatty acid and silicone oil with a solvent. The aforementioned chemical solution is coated on the n type oxide semiconductor layer 14 by means of a spin coater. The rotational frequency thereof is approximately 500 to approximately 3000 rpm. It is dried on a hot plate after the coating. The drying temperature on the hot plate is approximately 30° C. to approximately 200° C., for example, and the drying time thereon is approximately 5 minutes to approximately 30 minutes, for example. It is fired after the drying. In the firing performed after the drying, it is fired in the atmosphere using a baking furnace. The firing temperature is approximately 300° C. to approximately 600° C., and the firing time is approximately 10 minutes to approximately 60 minutes.
Consequently, aliphatic acid salt is decomposed and then a fine particle layer of a titanium dioxide covered with a silicone insulating film is formed. The above-mentioned manufacturing (preparation) method of forming the titanium dioxide layer covered with the silicone insulating film is a coating and thermodecomposition method. More specifically, the aforementioned layer has a structure where a metallic salt of the titanium dioxide coated with silicone is embedded in the silicone layer. After the firing, UV irradiation by means of a low pressure mercury lamp is implemented. The UV irradiation time is approximately 10 minutes to approximately 100 minutes. The layer thickness of the first charge layer 16 is approximately 200 nm to approximately 2000 nm, for example.
Second Charge Layer (Buffer Layer) 18
A chemical solution is formed by stirring silicone oil with a solvent. The aforementioned chemical solution is coated on the first charge layer 16 by means of the spin coater. The rotational frequency thereof is approximately 500 to approximately 3000 rpm. It is dried on a hot plate after the coating. The drying temperature on the hot plate is approximately 50° C. to approximately 200° C., for example, and the drying time thereon is approximately 5 minutes to approximately 30 minutes, for example. Furthermore, it is fired after the drying. In the firing performed after the drying, it is fired in the atmosphere using a baking furnace. The firing temperature is approximately 300° C. to approximately 600° C., and the firing time is approximately 10 minutes to approximately 60 minutes. After the firing, UV irradiation by means of a low pressure mercury lamp is implemented. The UV irradiation time is approximately 10 minutes to approximately 60 minutes. The layer thickness of the second charge layer (buffer layer) 18 after the UV irradiation is approximately 10 nm to approximately 100 nm, for example.
p Type Third Oxide Semiconductor Layer 24
The second charge layer 18 is formed by forming a nickel oxide (NiOyHx) film containing hydrogen through the sputtering deposition method. In this case, Ni or NiO can be used as a target. Water is extracted from vapor or moisture in the chamber of the sputter deposition apparatus. A film thickness of the p type oxide semiconductor layer (nickel oxide containing hydrogen (NiOyHx)) 24 is approximately 200 nm to approximately 1000 nm, for example.
Second Electrode 26
The second electrode 26 as an upper electrode is formed by forming Al as a film by means of a sputtering deposition method or a vacuum evaporation method, for example. The second electrode 26 can be formed on the p type oxide semiconductor layer (nickel oxide containing hydrogen (NiOyHx)) 24 using an Al target. The second electrode 26 may be formed only on a specified region using a stainless steel mask, for example.
Configuration of p Type Oxide Semiconductor Layer Containing Hydrogen
In the electricity storage device 30 according to the embodiments, the p type oxide semiconductor layer 24 is shown as a mixture layer of a nickel oxide NiO and a nickel hydroxide Ni(OH)2, for example, as shown in
Alternatively, in the electricity storage device 30 according to the embodiments, the p type oxide semiconductor layer 24 is shown as a mixture layer of a nickel oxide NiO, a nickel hydroxide Ni(OH)2, and a nickel oxyhydroxide NiOOH, for example, as shown in
Relationship Between Amount of Discharged Charge QD and Amount of Hydrogen CH
A relationship between total amount of hydrogen CH in the p type oxide semiconductor layer 24 and the amount of discharged charge QD proportional to the discharging time TD of the electricity storage device 30 are measured on the basis of an analysis result of Secondary Ion Mass Spectrometry (SIMS).
A charging voltage is applied to the electricity storage device 30 according to the embodiments for a predetermined time, and then a state between the first electrode E1 and the second electrode E2 is shifted to a opened state to measure the discharging time TD.
The discharging time TD of the electricity storage device 30 is changed by changing film formation conditions (including a film thickness) of the p type oxide semiconductor layer 24. It is proved that the discharging time TD can be increased by changing a sputtering flow rate condition and the film thickness.
The discharging time TD of the electricity storage device 30 can be increased by increasing the film thickness of the p type oxide semiconductor layer 24.
The discharging time TD can be increased by increasing the flow rate (pressure) of sputtering. Specifically, for example, it is proved that the discharging time TD can be increased by increasing the flow rate of Ar/O2 in the chamber in the sputtering.
It is also proved that the discharging time TD can be increased by increasing the film thickness tch of the first charge layer 16, in the electricity storage device 30 according to the embodiments.
Relationship Between Amount of Discharged Charge QD and Thickness tp of p Type Oxide Semiconductor Layer
The additive amount of the hydrogen H in the p type oxide semiconductor layer (nickel oxide containing hydrogen (NiOyHx)) 24 is substantially constant in a depth direction of the film, from the analysis result of the SIMS. Accordingly, the total amount of hydrogen in the p type oxide semiconductor layer 24 is increased in proportion to the thickness tp of the p type oxide semiconductor layer 24. Therefore, a relationship between the film thickness and the discharging time when the thickness tp of the p type oxide semiconductor layer 24 is changed under the same film formation conditions is measured to obtain a relationship between the amount of discharged charge QD and the thickness tp of the p type oxide semiconductor layer 24.
More specifically,
As shown in
Result of X-Ray Diffraction Measurement
Relationship Between Amount of Hydrogen CH and Pressure ΔP
As shown in
Relationship between Discharging Time TD and Thickness tp of p type Oxide Semiconductor Layer
In the electricity storage device 30 according to the embodiments, as shown in
Relationship Between Discharging Time TD and Thickness tch of First Charge Layer
In the electricity storage device 30 according to the embodiments, as shown in
Sputter Deposition Apparatus
As shown in
A heater 60 and a sample substrate 50 which can be heated with the heater 60 are disposed on the upper electrode 80.
Moreover, a magnet 90 is connected to the target 400, and thereby magnetic force lines 70 can be generated on the target 400 as shown in
Argon (Ar) gas and oxygen (O2) gas can be supplied into the chamber 500 at a predetermined flow rate from the gas introduction port 100.
Exhaust gas after the sputter deposition reaction is discharged from the gas exhaust port 200. The gas exhaust port 200 is connected to a cryopump or a turbo molecular pump, for example, disposed outside the chamber 500.
As the target 400, metal Ni or NiO can be applied.
As the sample substrate 50, a substrate sample of which a exposed surface is the first charge layer 16 can be applied, wherein the substrate sample has a layered structure composed by including the first charge layer 16/the first oxide semiconductor layer 14 or a layered structure composed by including the first charge layer 16/the first oxide semiconductor layer 14/the first electrode (E1), in the electricity storage device 30 according to the embodiments.
A high frequency power supply 300 which can be excited at a predetermined frequency is connected between the upper electrode 80 electrically connected to the chamber 500 and the target 400 electrically insulated to the chamber 500. Consequently, a given amount of plasma composed by including argon ions Ar+ and electrons e− is generated between the upper electrode 80 and the target 400 in the chamber 500, and thereby Ni atoms are excited from the target 400 due to an ion bombardment with the argon ions Ar+. The excited Ni atoms react with the hydrogen and the oxygen in the chamber, and undergo a sputter deposition reaction on a front side surface of the sample substrate 50, and thereby the p type oxide semiconductor layer 24 containing hydrogen is deposited thereon. As a result, the p type oxide semiconductor layer 24 is shown as a nickel oxide (NiOyHx) containing hydrogen.
Even if conversion is performed per unit film thickness (volume) of the p type oxide semiconductor layer 24, the discharging time can be increased by increasing the hydrogen (H) concentration. Accordingly, vapor and H2O may be supplied into the chamber at the time of the sputtering, for example.
RBS
Although SIMS can perform a mutual comparison but cannot measure an absolute amount, it was also quantified by Rutherford Backscattering Spectroscopy (RBS). In the RBS, when high-speed ions (He+, H+, and the like) are emitted to the sample, a part of the incident ions receives elastic (Rutherford) scattering by the atomic nucleus in the sample. Energy of the scattered ions varies depending on the masses and positions (depth) of the object atoms. An elemental composition of the sample in the depth direction can be obtained from the energy and the amount of the scattered ions. Consequently, as an example, a result of 35.20% of Ni content, 35.60% of O content, and 29.00% of H content is obtained, and thereby it is proved that approximately 30% of hydrogen (H) is contained in the atomic weight ratio.
In the electricity storage device 30 according to the embodiments, it is estimated that nickel oxide (NiOyHx) containing 15% or more of hydrogen (H) in the atomic weight ratio is required for discharging. Alternatively, it is preferable that it may be y=optional value and x=0.35 or more for the amount of the hydrogen for the nickel oxide (NiOyHx) which contains hydrogen (H), in the chemical formula.
When H is purely contained in the nickel oxide (NiO), x of NiOHx may be approximately 0.35. However, since NiOOH or Ni(OH)2 may be contained in the nickel oxide (NiO), it is preferable that it may be y=optional value and x=0.35 or more for the nickel oxide (NiOyHx) containing hydrogen.
Although only NiO is detected by the XRD, this is because a case where oxygen exceeding 1 with respect to Ni by measurement of the RBS is confirmed, and the amount of the hydrogen contributes to the charging and discharging if defining the amount of the hydrogen on the basis of Ni. As a result of the RBS measurement, NiOyHx (where y=1 and x=0.8) is obtained in a certain sample, and NiOyHx (where y=1.5 and x=0.4) is obtained in another sample, for example.
According to the embodiments, there can be provided the electricity storage device capable of increasing the electricity storage capacity per unit volume (weight), and the manufacturing method for such an electricity storage device.
As explained above, the embodiments have been described, as a disclosure including associated description and drawings to be construed as illustrative, not restrictive. This disclosure makes clear a variety of alternative embodiments, working examples, and operational techniques for those skilled in the art.
For example, a structure of the electricity storage device 30 according to the embodiments is made in a sheet shape by using stainless steel foil as a substrate. Subsequently, this sheet may be laminated to produce the electricity storage device 30 with a required capacity.
For example, an electricity storage device with a required capacity can be manufactured by opposing two sheets of the second electrodes (upper electrodes), inserting an electrode (thin metal foil) therebetween, and laminating the two sheets in multiple layers. It may be sealed with a laminate or the like after the laminating.
Such being the case, the embodiments cover a variety of embodiments, whether described or not.
The electricity storage device of the embodiments can be utilized for various consumer equipment and industrial equipment, and can be applied to wide applicable fields, such as electricity storage devices for system applications capable of transmitting various kinds of sensor information with low power consumption, e.g. communication terminals and electricity storage devices for wireless sensor networks.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-049544 | Mar 2017 | JP | national |
This application is a continuation of international patent application number PCT/JP2018/007770, having an international filing date of Mar. 1, 2018, which claims priority to Japan patent application number P2017-049544, filed on Mar. 15, 2017. The content of the referenced applications is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2018/007770 | Mar 2018 | US |
| Child | 16569322 | US |
