JP2715638B2 - Manufacturing method of silver ion conductive solid electrolyte thin film - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silver ion conductive solid electrolyte thin film, and more particularly to silver used for an element utilizing an electrochemical phenomenon such as a battery, a capacitor, an electrochromic display, and an ionic memory. The present invention relates to a method for producing an ion-conductive solid electrolyte thin film.

2. Description of the Related Art An element utilizing electrochemical phenomena is composed of an electrolyte and a pair of electrodes disposed via the electrolyte.

Examples of the electrolyte used in such an element include a liquid electrolyte and a solid electrolyte conventionally used in batteries.

However, when a liquid electrolyte is used, it is difficult to miniaturize the battery, and the problem of liquid leakage cannot be eliminated.

On the other hand, if the battery is made solid using a solid electrolyte, such problems can be solved, reliability can be improved, and the battery can be miniaturized and thinned. The miniaturization of the element aims at application as an ionic memory (a potential storage element in which a microminiature battery is integrated) and an image display element (a potential storage element in which a microelectrochromic element is integrated).

One of the electrolytes used for such a device is a silver ion conductive solid electrolyte. For example _{AgI-Ag 2 O-MO y} (M is
At least one element selected from W, Cr, Mo, P, V, Te, Se, As, B, Si, and Ge) solid electrolytes, which are AgI, Ag _x MO _y , A
g can be formed by sequentially depositing g on a silver electrode and then oxidizing it by heating in an oxidizing atmosphere.

However, when a solid electrolyte thin film is formed using the solid electrolyte, when a solid electrolyte thin film having a thickness of 3,000 mm or more is formed in a single step, the composition in the thin film becomes non-uniform, In addition, cracks occur in the film. Therefore, there is a problem that the ion conductivity decreases in the film thickness direction and a short circuit between the electrodes occurs due to cracks in the film.

An object of the present invention is to solve the above problems and provide a method for producing a good silver ion conductive solid electrolyte thin film.

Means for Solving the Problems In order to solve the problems, a method for producing a silver ion conductive solid electrolyte thin film of the present invention is based on AgI, Ag _x MO _y (x is 0 <x ≦ 1).
, Ag is sequentially deposited, and the deposited layer is heated and oxidized in an oxidizing atmosphere to obtain AgI-Ag ₂ O-MO _y (M is W,
At least one element selected from the group consisting of Cr, Mo, P, V, Te, Se, As, B, Si, and Ge, and y is an integer determined by the valency of M). By repeating the process a plurality of times, a solid electrolyte thin film having a desired thickness in which a plurality of the solid electrolyte layers are stacked is obtained.

In the multilayer films of action AgI-Ag _x MO _y -Ag, with silver diffuses into Ag _x MO _y layer, a silver Ag _x MO _y layer is oxidized during heating
It becomes oxygen silver of Ag ₂ O-MO _y, further forming a solid electrolyte thin film of AgI-Ag ₂ MO _y reacts with silver iodide. Further, the AgI, Ag _x MO _y, rather than each silver layer is laminated surface of Ag, when formed therein, hardly occurs thermal oxidation of the silver layer, it is impossible to obtain a good solid electrolyte thin film.

Although the solid electrolyte thin film can be easily prepared by the above method, the reaction between the layers becomes insufficient when the film thickness is large, and a large number of cracks are formed in the film due to a volume change accompanying the reaction. . For this reason, a thin film having a small thickness is formed which easily reacts and is hardly affected by a change in volume, and a solid electrolyte thin film having a large thickness is formed by laminating the films.

Hereinafter, the silver ion conductive solid electrolyte thin film of one embodiment of the present invention will be described in detail with reference to the drawings.
The present invention is not limited to these examples. Example 1 An Ag ₆ I ₄ WO ₄ silver ion conductive solid electrolyte thin film was produced by the following method.

FIG. 1 shows a process chart for producing the silver ion conductive solid electrolyte thin film of the present invention.

First, as shown in FIG. 1 (A), a predetermined amount of a material obtained by adding silver to silver iodide by 15% by weight is put into a heating boat of a resistance heating vapor deposition apparatus, and is heated and vapor-deposited to a thickness of 2500 mm on a glass substrate 9.
A silver iodide thin film 10 was produced.

Next, silver tungsten monoxide is deposited on the silver iodide thin film 10.
An Ag _0.2 WO ₃ thin film was prepared by the following method. A material powder in which silver and tungsten oxide were mixed at a molar ratio of 1: 5 was press-molded at 1 t / cm ² , and then sealed in a quartz glass tube.
After firing for a time, silver tungsten monoxide Ag _0.2 WO ₃ was synthesized. A predetermined amount of this silver tungsten monoxide, Ag _0.2 WO ₃ , was placed in a heating boat of a resistance heating vapor deposition apparatus, heated and vapor-deposited, and a 700-mm-thick silver monoxide was deposited on the silver iodide thin film as shown in FIG. A tungsten Ag _0.2 WO ₃ thin film 11 was produced. further,
As shown in FIG. 1 (C), a predetermined amount of silver was put in a heating boat of a resistance heating evaporation apparatus, and a silver thin film 12 having a thickness of 200 ° was finally formed.

This laminated film was placed in the air for 300 minutes as shown in FIG.
By heat oxidation treatment at 6 ° C. for 6 hours, an Ag ₆ I ₄ WO ₄ silver ion conductive solid electrolyte thin film 13 having a thickness of 2800 ° was prepared.

Then, the solid electrolyte layer is laminated on the solid electrolyte thin film 13 by repeating the thin film forming steps (A) to (D) shown in FIG. 1 again (FIGS. 1 (E) to (H)). An Ag ₆ I ₄ WO ₄ silver ion conductive solid electrolyte thin film 17 having a thickness of 55005 was produced.

On the silver ion conductive solid electrolyte thin film 17 formed on the glass substrate 18 thus obtained, a metal silver thin film (width 1 mm, distance between electrodes 1 mm) 1 as a reversible electrode as shown in FIG.
9,20 mm is formed and its total electric conductivity is measured by the AC complex impedance measuring method. The platinum thin film 2,000 mm (width 1 mm) 21 is used as a blocking electrode with the electronic conductivity being 1 mm between the metallic silver thin film 20 and the electrode. It was formed by electron beam heating evaporation and resistance heating evaporation and measured by Wagner measurement.

As a result, the total conductivity of the obtained silver ion conductive solid electrolyte was 9 × 10 ⁻³ S / cm, and its electronic conductivity was 2 × 10 ³ S / cm.
It was 10 ^-10 S / cm.

Further, as shown in FIG. 3, a thin film 24 of a silver ion conductive solid electrolyte Ag ₆ I ₄ WO ₄ is formed on a glass substrate 22 having a platinum thin film 2000Å23 formed thereon in the same manner as described above, and a metal is formed thereon. A silver thin film 25 was formed by 2000 mm, and the total electric conductivity and the electronic electric conductivity in the thickness direction were measured.

As a result, the total conductivity was 4 × 10 ⁻³ S / cm and the electronic conductivity was 9
× 10 ⁻¹¹ S / cm.

As a result, the silver ion conductive solid electrolyte Ag ₆ I ₄ WO ₄ thin film produced by the production method of this example has excellent silver ion conductivity in the plane direction and the film thickness direction, and has an electronic insulating property. Was found to be excellent.

EXAMPLE _{2 4AgI-Ag 2 O-B} 2 O 3 silver-ion-conducting solid electrolyte film was prepared in the following manner.

First, a thin film of silver iodide having a thickness of 2500 ° was formed on a glass substrate in the same manner as in FIG. 1 shown in Example 1.

Next, on this silver iodide thin film, silver boron monoxide Ag _0.2 B ₂ O
The thin film of No. ₃ was produced by the following method.

A material powder obtained by mixing silver and boron oxide B ₂ O ₃ at a molar ratio of 1: 5 is press-molded at 1 t / cm ² , sealed in a quartz glass tube, and calcined at 600 ° C. for 6 hours for silver monoxide. Tungsten Ag _0.2
B ₂ O ₃ was synthesized.

A predetermined amount of this silver boron monoxide Ag _0.2 B ₂ O ₃ is placed in a heating boat of a resistance heating vapor deposition apparatus, and is heated and vapor-deposited to form a 700-mm-thick silver boron monoxide Ag _0.2 B ₂ O on a silver iodide thin film. _Three thin films were prepared.

Further, a predetermined amount of silver was put into a heating boat of a resistance heating evaporation apparatus, and a silver thin film having a thickness of 200 mm was finally formed.

This laminated film was heated and oxidized in air at 300 ° C. for 6 hours to produce a solid electrolyte thin film.

Then, a solid electrolyte layer is laminated on the solid electrolyte thin film by repeating the above-mentioned thin film forming process again,
The _{4AgI-Ag 2 O-B 2} O 3 silver-ion-conducting solid electrolyte thin film having a thickness of 5500Å was prepared.

On the silver ion conductive solid electrolyte thin film thus obtained, a metal silver thin film (width: 1 mm, distance between electrodes: 1 mm) was formed as a reversible electrode as shown in FIG. Measured by the complex impedance measurement method, and used a platinum thin film 2000
{(Width 1 mm) and metallic silver thin film (width 1 mm) 2000} were formed by electron beam heating evaporation and resistance heating evaporation at an electrode spacing of 1 mm, and measured by Wagner measurement.

As a result, the total conductivity of the obtained silver ion conductive solid electrolyte was 3 × 10 ⁻³ S / cm, and its electronic conductivity was 4 × 10 ⁻³ S / cm.
It was 10 ^-10 S / cm.

Furthermore, on a glass substrate on which 2000 mm of platinum thin film was formed,
A thin film of silver ion conductive solid electrolyte _{4AgI-Ag 2 O-B 2} O 3 is formed in a manner similar to that shown in FIG. 3, was measured total Conductivity and electron conductivity of the film thickness direction.

As a result, the total conductivity was 1 × 10 ⁻³ S / cm, and the electronic conductivity was 1
× 10 ⁻¹⁰ S / cm.

As a result, the silver ion conductive solid electrolyte 4AgI-Ag ₂ O-B ₂ O ₃ thin film produced by the production method of the present invention has excellent silver ion conductivity in the plane direction and the film thickness direction, and
It turned out that it was excellent in electronic insulation.

Above, an example using WO ₃ , B ₂ O ₃ as a silver ion conductive solid electrolyte was shown, but other oxides CrO ₃ , MoO ₃ , P ₂ O ₅ , V
Similar effects can be obtained by using ₂ O ₅ , TeO, SeO ₂ , As ₂ O ₃ , SiO ₂ , and GeO ₂ .

Advantages of the Invention As is clear from the description of the above embodiments, according to the method for producing a silver ion conductive solid electrolyte thin film of the present invention, an element is integrated and an ionic memory (a potential storage element in which a microminiature battery is integrated) or A silver ion conductive solid electrolyte thin film which can be applied to an image display element (a display element in which a micro electrochromic element is integrated) or the like can be easily obtained.

[Brief description of the drawings]

1 (A) to 1 (H) are process charts of the solid electrolyte thin film shown in Examples 1 and 2 in the method for producing a silver ion conductive solid electrolyte thin film according to one embodiment of the present invention, FIG. Is a cross-sectional view showing a configuration of a cell for measuring total and electronic conductivity in the same plane direction, and FIG. 3 is a cross-sectional view showing a configuration of a cell for measuring total and electronic conductivity in the same film thickness direction. FIG. 9: Glass substrate, 10, 14: AgI layer, 11, 15: Ag _0.2 WO
₃ layers, 12,16 ... Ag layer, 13,17 ... Solid electrolyte thin film.

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-54-102526 (JP, A) JP-A-50-16836 (JP, A) JP-A-50-10453 (JP, A)

Claims (1)

(57) [Claims] 1. After sequentially depositing AgI, Ag _x MO _y (x is any number in the range of 0 <x ≦ 1) and Ag, the deposited layer is heated and oxidized in an oxidizing atmosphere to obtain AgI-Ag ₂ O−MO _y (M is W, Cr, Mo, P, V,
At least one element selected from the group consisting of Te, Se, As, B, Si, and Ge, and y is an integer determined by the valency of M) The solid electrolyte layer is repeatedly formed a plurality of times to obtain the solid electrolyte. A method for producing a silver ion conductive solid electrolyte thin film, comprising obtaining a solid electrolyte thin film having a plurality of layers laminated.