JPS5935170B2 - electric double layer capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an inexpensive, long-life, large-capacity electric double layer that prevents the precipitation and dissolution of Cu+ ions at the interface between a copper ion conductive solid electrolyte and activated carbon or CuS. The purpose is to provide capacitors.

Conventionally, in a capacitor that utilizes the electric double layer capacitance formed at the interface between a polarizable electrode and a solid electrolyte, RbAg4l
A silver ion conductive solid electrolyte such as 5t Ag3SI e Ag6I4WO4 was used, a carbon electrode or Ag2 S e Ag3 PO4 electrode was used as the polarizable electrode, and a non-polarizable copper electrode was always used as the counter electrode. .

Since the capacitor is constructed of Ag and silver salt in this way, it is inevitable that the capacitor will be expensive.

In addition, the decomposition voltage of silver salt is extremely low, and the linear relationship between the amount of electricity and the voltage at the carbon electrode is from 0 to 0.
5 V p Ag2 S e -Ag3 PO is 0 to 0.12 V at the 4 poles.

On the other hand, the inventors found that a capacitor using a mixture of a copper ion conductive solid electrolyte and carbon as a polarizable electrode and a mixture of copper powder as a counter electrode also has a large capacity, and the operating voltage is 0 to 0.6. ■I discovered that it can be made bigger.

However, unlike silver, redox of the counter electrode is not reversible over a wide temperature and current density range.

It is clear that at a current density of 0.6 mA 10r/IJJ at a low temperature below 0°C, the amount of copper deposited increases as the cycle is repeated, eventually leading to a short circuit, resulting in a short life. Ta.

The present invention relates to improvements thereto.

Cuprous sulfide is C continuously from Cub, 68 to Cu2S.
The u+ ion defect changes, and the potential change during that time is 13.5 m.
It is V.

Taking this as a counter electrode, during this composition Cu metal precipitation =
This method takes advantage of the fact that since no dissolution occurs, short circuits due to Cu accumulation do not occur.

An embodiment of the present invention will be described with reference to FIG.

In Fig. 1, 1 is a carbon electrode in which activated carbon and electrolyte are mixed at a ratio of 10 wt% activated carbon, and 8
After heating for hours, it was press-fitted into a stainless steel cup 2, which is a current collector plate.

3 is cuprous bromide and methyl bromide triethylenediamine,
Alternatively, mix methyl bromide and hexamethylene-))lamin at a molecular ratio of 7:1 and hold each at 230°C.
Alternatively, the reaction may be caused by heating at 160°C.

4 is a polarizable electrode in which Cu x S and electrolyte were mixed at a ratio of 90 wt CuS and heated at 230° C. for 8 hours.

5 is a stainless steel mesh current collector.

6 is a Cu2S reference electrode, and 7 is a current collector made of copper mesh.

8, 9, and 10 are lead wires connected to the carbon electrode-CuxS counter electrode and the Cu2S reference electrode, respectively.

11 is an aluminum container for packaging, 12 is a rubber backing 13 is a phenol resin plate.

Reference numeral 14 is an epoxy resin body for completely sealing the opening.

Mixed powder 1 of activated carbon and electrolyte is temporarily pressed into a stainless steel cup 2, then electrolyte powder 3 is added and temporarily pressed, further mixed powder 4.6 of CuxS and electrolyte is placed and temporarily pressed, and finally, stainless steel Place net 5 and copper net 7, 4t/
A molded body was made by pressing at a pressure of 7.

Next, after cutting the counter electrode and the reference electrode with gold ore, the tender rubber plate 12 is placed on the aluminum container 11, and the leads 9 and 10 are connected to the current collectors 5 and 7, respectively, using silver paint. The upper edge of the container 11 is curled and sealed.

The example in Figure 1 is of a three-pole configuration using a reference pole,
As shown in Figure 2, carbon electrodes do not exhibit polarization due to resistance when energized, and also exhibit a highly reproducible potential change that is proportional to the amount of electricity applied, so it is possible to provide a highly reproducible potential indication without polarization due to resistance. , exhibits excellent characteristics as an integration/timing element.

However, when storing energy or simply using a large capacity, there is no need to use a reference electrode.

A stainless steel mesh is used as the current collector of the CuxS electrode, and no separation is performed.

Carbon electrode mixture weight 32, electrolyte 1.51, Cu
x S pole weight 2.01, make a capacitor with a diameter of 20 wl1, first use the carbon electrode as the cathode and apply current at 1 mA for 2 hours, then apply the same current and time to the anode.
Figure 2 shows the potential changes at both poles when electricity is applied to the dick.

The potential of the counter electrode shows a change due to ohmic resistance and a slight attenuation due to discharge, but with the force of the carbon electrode, the potential change is linear with respect to the amount of energized electricity, there is no change due to leaving it, and the direction of the current force is Even when reversed, it is recognized that the potential changes reversibly.

FIG. 3 shows the change in DC capacity due to repetition of the above cycle when the counter electrode of the present invention is used in comparison with that for a conventional copper electrode.

The DC capacity was determined from the equation shown in FIG. 2, which is the potential change Δ■ volts during energization.

In FIG. 3, 1 is the one of the present invention, and 2 is the conventional copper electrode.

While the DC capacity of the conventional device rapidly increased after about 250 cycles, the device of the present invention shows no change even after 5,000 cycles, and is recognized to have an extremely long life.

As described above, the present invention uses polarizable electrodes CuxS (x: 1.8 to 2.0) instead of conventional non-polarizable copper electrodes.
), it is possible to create an element that has the same performance as before and has a significantly longer cycle life.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of an electric double layer capacitor that is an embodiment of the present invention, Fig. 2 is a characteristic diagram showing changes in the potential of both electrodes due to energization of the capacitor, and Fig. 3 is a diagram showing the same capacitor and a conventional electric double layer capacitor. FIG. 3 is a characteristic diagram showing a change in DC capacitance due to repeated cycles of a capacitor. 1... Carbon electrode, 2... Stainless steel cup, 3... Mixture, 4... Polarizable electrode, 5, 7... Collection Electrical body, 6...Reference electrode, 8...Carbon electrode, 9...Counter electrode, 10...Carbon electrode, 11...Package Aluminum electrode, 12...Rubber backing, 13...Phenol resin plate, 14...
・Resin body.

Claims (1)

[Claims] A molded mixture of activated carbon and electrolyte as a polarizable electrode of 1-force, Cu x S (x: 1) as the other polarizable electrode.
．． 8 to 2.0) and an electrolyte, a layer of a molded product of Cu + ion conductive solid electrolyte of the same quality as the electrolyte is interposed between these electrode molded products, and Cu is used as the current collector of each electrode. An electric double layer capacitor characterized by using graphite, stainless steel, or tungsten, which is unlikely to cause precipitation. 2. Claims characterized in that the voltage between the bipolarizable electrodes is operated below the decomposition voltage of the Cu+ ion conductive electrolyte, and control is performed using the voltage between the two electrodes or the voltage of the activated carbon electrode relative to the reference electrode. The electric double layer capacitor according to item 1.