JPS6340324B2 - - Google Patents

Description

[Detailed description of the invention] The present invention has high ionic conductivity near room temperature,
Furthermore, the present invention provides a stable copper ion conductor with a small electron transport number and a method for producing the same.

Conventionally, there are silver ion conductors in which AgI is partially substituted with anions, cations, or mixed anions and cations as substances that exhibit high ionic conductivity at room temperature. Batteries using this material, electric double layer capacitors, and display elements using WO ₃ have also been developed, but since they are mainly composed of silver and silver salts, they are expensive and have not become very popular. Ta.

In response, attempts have been made to use copper ion conductors, but the materials that have been obtained so far that exhibit high ionic conductivity have low heat resistance or high temperature because they use organic materials. However, it had the disadvantage of having a narrow practical temperature range due to its high electronic conductivity.

In contrast, the inventors found that 1/5 of the Cu ⁺ ions in CuCl are Rb ⁺ , K ⁺ , NH ₄ ⁺ , and NR ₄ ⁺ , and 1/3 to 1/4 of the Cl ^- ions are I ^- ions. We have already found that the mixed-substituted materials exhibit relatively high Cu ⁺ ion conductivity at room temperature and have a relatively wide practical temperature range.

The present invention replaces Cu ⁺ ions with Rb ⁺ , K ⁺ ,
Rb ⁺ and K ⁺ than NH ₄ ⁺ , NR ₄ ⁺ ions alone
This was based on the discovery that replacing cations with two types of cations has higher ionic conductivity, lowers internal resistance when used in devices such as batteries, and allows even larger currents to flow. It is.

Embodiments of the present invention will be described below with reference to the drawings. KCl, pre-heated at 140 °C for 2 hr in air
RbCl, CuCl, and CuI were mixed in a mortar at a ratio of MeCu ₄ I _1.5 Cl _3.5 . As Me, only Rb (conventional) and a mixture of K and Rb (invention) were used.
These mixtures were press-molded into pellets, placed in a sealed glass container, the inside of which was evacuated, and then heated at 250° C. for 17 hours to cause a reaction. When the product was subjected to X-ray diffraction, a substance completely different from the raw material was formed as shown in Figure 1, and it was confirmed that this crystal had the same structure as the conventional RbCu ₄ I _1.5 Cl _3.5 . Further, the relationship between the composition, lattice constant, and room temperature conductivity is as shown in FIG. 2, and the addition of K reduces the lattice constant and the conductivity decreases by about 50% in the composition range of the present invention. Since the electron transport number is extremely low as in the conventional case, it is clear that the increase in electrical conductivity is due to the increase in ionic conductivity.

Next, the effects when the electrolyte according to the present invention is used in an electric double layer capacitance applied element as an electrochemical device will be described. The third configuration of the electric double layer capacitance applied element
As shown in the figure. In the figure, 1 is a polarizable electrode, and the material is carbon, which has electronic conductivity like Cu ₂ S.
An electrode made of a molded mixture of an electrochemically inert substance and an electrolyte. The differences depending on the electrode material are as follows. Carbon, platinum, palladium, etc. do not cause an electrochemical reaction at the electrode when energized within the voltage range of the electrolyte decomposition voltage (approximately 0.6V).
The decomposition voltage of the electrolyte can be a withstand voltage, but the adsorbed gas will undergo an electrochemical reaction even below the withstand voltage.
If care is not taken to remove it, it will appear as a leakage current. Although Cu ₂ S has low leakage current, it has the disadvantage that the voltage range in which electrochemical reactions do not occur is narrow at 0.07V. Reference numeral 2 denotes a current collector for the polarizable electrode 1, which is formed of graphite, platinum, palladium, or gold by vapor deposition or sputtering. 3 is an electrolyte. 4 is the opposite
₂ :3 mixture of Cu2S and Cu, 3:3 of _TiS2 and Cu
7 mixture, or a mixture of Cu ₂ S alone and an electrolyte. These are called non-polarizable electrodes, and the precipitation and dissolution reactions of Cu ⁺ ions are carried out by applying electricity. The mixture electrode has an open circuit voltage close to that of Cu and has better reversibility than the Cu electrode.
The difference is that Cu ₂ S alone exhibits an open circuit voltage of 310 mV higher than that. Reference numeral 5 denotes a current collector for the counter electrode 4, and the copper is either press-fitted into the counter electrode 4 as a net or deposited on the counter electrode 4 by vapor deposition. 6 is an electrolyte, and 7 is a reference electrode, in which a mixture of Cu ₂ S and an electrolyte is used. 8 is a current collector of the reference electrode 7, which is made of copper. Note that the electrolyte 6, the reference electrode 7, and the current collector 8 are provided to accurately measure potential changes of each electrode, and are not necessary for a capacitor for obtaining an output.

Using Cu ₂ S for polarizable electrode 1 and a mixture of Cu ₂ S and Cu for counter electrode 4, 0.1 g of polarizable electrode 1 and 0.2 g of other electrodes and electrolyte were collected to form a 10 mmφ cylindrical element. . Figures 4 and 5 show the respective characteristics when the electrolyte according to the present invention is used as the electrolyte (shown in area A in the figure) and when an electrolyte for comparison is used (shown in area B in the figure). shows. FIG. 4 shows the potential change due to current flow of the polarizable electrode and the potential change after the current supply is stopped. When a conventional electrolyte is used, when a current of 20 mA is applied, a potential change occurs, which is thought to be due to a delay in the movement of ions in the electrolyte, and there is a delay in potential rise (a), and a large overshoot (b) and decrease (c) in the potential after the current is stopped. When Natsuta used the electrolyte according to the present invention, such a problem did not occur, but only after 30 mA of current was applied.

The potential change of the counter electrode was as shown in FIG. 5, and the polarization was significantly reduced by using the electrolyte according to the present invention. If the polarization of the opposite electrode can be ignored, even a device with a two-pole configuration can show the potential behavior of the polarizable electrode depending on the terminal voltage without using a reference electrode, and the linearity of the potential with respect to the current flow rate of the polarizable electrode It is possible to simplify the configuration of a potential storage element that uses potential retention when power is stopped, or to store electrical energy.
When used as a discharge capacitor, it also has the advantage of reducing energy loss.

In the above example, the case where the electrolyte according to the present invention is used in an electric double layer capacitor is shown, but the difference is that the electrolyte according to the present invention is used in an electric _double layer capacitor. Since both use only non-polarizable electrodes, they have exactly the same effect of reducing loss due to current flow.

[Brief explanation of the drawing]

Figure 1 shows a conventional copper ion conductor (RbCu ₄ I _1.5
An X-ray diffraction diagram of the copper ion conductor according to the present invention shown in comparison with Cl _3.5 ), FIG. 2 is a diagram showing the lattice constant and conductivity of the copper ion conductor according to the present invention,
Figure 3 is a cross-sectional view showing the configuration of an electric double layer capacitance applied element using a copper ion conductor as an electrolyte;
The figure shows the potential change of the polarizable electrode of an electric double layer capacitance application device using the copper ion conductor according to the present invention and the conventional copper ion conductor as electrolytes, and Fig. 5 shows the same electric double layer capacitance application device. It is a figure which shows the potential change of the counter electrode of. 1... Polarizable electrode, 3, 6... Electrolyte, 4...
Opposite pole, 7...Reference pole.

Claims (1)

[Claims] 1. In the compound represented by the chemical formula MeCu ₄ I _2-x Cl _3+x (0.25x0.5), the above Me is 1:9 to 1:
A copper ion conductor characterized by using a compound consisting of K and Rb in No. 3. 2 In the compound represented by the chemical formula MeCu ₄ I _2-x Cl _3+x (0.25x0.5), the above Me is 1:9 to 1:
In the method for producing a copper ion conductor using a compound consisting of K and Rb in No. 3, KCl, RbCl, CuCl,
After mixing CuI at a predetermined ratio and press-molding the pellets into a sealed container and evacuating the inside,
A method for producing a copper ion conductor, characterized in that the above compound is obtained by a heating reaction. 3. The method for producing a copper ion conductor according to claim 2, characterized in that the pellets are heated at a temperature of 200 to 300°C.