JPS62126567A - Solid hydrogen battery - Google Patents

Abstract

PURPOSE:To obtain a positive electrode which makes high rate discharge possible, has high equilibrium voltage, and good cycle performance by forming a positive electrode with a material mainly comprising lead peroxide. CONSTITUTION:PbO2 is used as a material for a positive electrode 2, and an adequate amount of carbon powder such as acetylene black is added to it. Thereby, the positive electrode which makes high rate discharge possible, has high voltage, and good cycle performance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a solid-state hydrogen battery in which a negative electrode active material, an electrolyte, and a positive electrode material are all solid, and particularly relates to a positive electrode material thereof.

<Prior art> In recent years, with the development of semiconductor technology and its applied technologies,
The power consumption of electronic devices is gradually decreasing. In addition, batteries used in these electronic devices are desired to be smaller and thinner as power consumption decreases, and at the same time, they are also required to be highly reliable. Solid electrolyte batteries are generally known as batteries that meet these demands. Solid electrolyte batteries use a solid electrolyte with ionic conductivity, so there is no leakage from the battery, and highly automated semiconductor manufacturing technology can be applied to the manufacturing process, making it easy to mass produce. It has the following characteristics.

Already, such solid electrolyte batteries include silver, copper,
Lithium-based batteries are being developed. Among these, batteries using silver ion or copper ion conductors as solid electrolytes are characterized in that these solid electrolytes have relatively high ionic conductivities, and therefore can be discharged at large currents. On the other hand, lithium-based solid electrolyte batteries have high energy density and high output voltage, but the ionic conductivity of the solid electrolyte used here is not very high, so they cannot be discharged with a large current. In addition, since the lithium metal used in the negative electrode is extremely active, it requires oxidation and moisture resistance.
Therefore, the battery manufacturing process and sealing technology become complicated. Furthermore,
When considering the use of solid-state batteries in any of the above systems as secondary batteries, the major problem remains that the conductive species that are reduced at the negative electrode precipitate in a dendritic form during charging, resulting in poor cycle life and the inability to perform deep discharge. ing.

<Background of the Invention> The present inventors have proposed a method in which the negative electrode active material is a hydrogen storage material that stores hydrogen as a metal hydride, the solid electrolyte is a hydrogen ion conductor, and the positive electrode active material is a guest material that accepts hydrogen ions. I have already proposed that it can be used as a battery by doing this. In the case of this battery, it is possible to discharge with a large current, and since the active material used in the negative electrode is hydrogen, it is a diffusion type electrode in which only the diffusion of hydrogen participates in the reaction, so it is possible to discharge with a large current. Unlike precipitated electrodes using C as a conductive species, there are no dendritic precipitates produced by repeated charging and discharging, and this has the advantage of a long cycle life. Furthermore, since there are no tree branches, short circuits between the positive and negative electrodes do not occur.

Although it is possible to construct a battery using any material that accepts hydrogen ions as a guest substance for the positive electrode mentioned above, the voltage obtained depending on the material used, the current density that can be discharged, and the secondary The cycle characteristics of batteries are different.

<Objective of the Invention> An object of the present invention is to provide a solid hydrogen battery that can obtain a high voltage and a large discharge current, and has a positive electrode that has good repeated cycle characteristics during charging and discharging.

Description of structure and effects> Electromotive reaction of a hydrogen solid electrolyte battery using a hydrogen storage material for the negative electrode, a substance that can accept hydrogen ions as a guest substance for the positive electrode, and a hydrogen ion conductive solid electrolyte for the electrolyte. is considered to be as follows.

・・・・・・・・・(2) or 10XH2O・・・・・・・・・(4) Here, Metal is a hydrogen storage material, and AB.

is a substance that can accept hydrogen ions as a guest substance. As shown in the reaction formula above, it is not fully understood whether hydrogen ionic conduction is via water, but antimony pentoxide (Sb20.. Hydrogen ion conductive oxides such as nH2O, tin dioxide (S n 02 ・n H2O), solid polymer electrolytes represented by perfluorocarbon ion exchange membranes, etc. are used. Depending on the negative electrode material and positive electrode material used. The potential obtained varies.As a result of examining various electrode materials, we found that Pb was used as the positive electrode material.
By using O3 and adding an appropriate amount of carbon powder such as acetylene black as necessary, it has become possible to realize a positive electrode that has a high equilibrium voltage, is capable of large current discharge, and has good cycle characteristics.

<Example 1> Commercially available titanium (Ti) (purity 99.5%) and nickel (
Ni) (purity 99.95%) and Missini Metal (Mm)
are weighed and mixed so that the atomic ratio is 7 i N f Mmo,01. This is melted in an arc melting furnace. This alloy is placed in a stainless steel reaction vessel, and high-pressure hydrogen gas is introduced and heated to hydrogenate it. The hydrogenated alloy is taken out and pulverized to a particle size of 44 grains or less in an argon gas atmosphere. 0.01f of acetylene black was mixed with 0.2f of this powder, and 0.01f of antimony pentoxide, which is a solid electrolyte to be described later, was mixed.
．． Add 11, mix, and form into pellets using a tablet machine. This is used as the negative electrode. Next, commercially available antimony pentoxide (
SbC1,) is dropped into pure water, and the resulting precipitate is separated, washed, and dried to obtain antimony pentoxide. This antimony pentoxide 0.12 is molded into pellets using a tablet molding machine. This is used as a solid electrolyte. Next, using commercially available lead peroxide (Pb03) (purity 97%) 0.22, acetylene black 0.02F and antimony pentoxide 0.05F mentioned above are mixed with this, and the mixture is molded into pellets using a tablet molding machine. . This is used as the positive electrode. Using these, a battery having a structure as shown in FIG. 1 is constructed. That is, a solid electrolyte 3 is inserted between a positive electrode 1 and a negative electrode 2, a current collector plate 4 is arranged on both the positive and negative electrode surfaces, a lead wire 5 is connected, and these are integrally connected with a holding plate 6 and a screw 7. A solid electrolyte battery is produced by sandwiching the two. The initial open potential at 25°C is 1430mV
Met. Thereafter, discharge was performed at a current density of 100 μA/i per electrode area. The results are shown in FIG. The horizontal axis is time and the vertical axis is volts. Also, per electrode area! 00
A charge/discharge test was performed every hour at 25° C. at a current density of μA/i.

The results are shown in FIG. Similarly, the horizontal axis is time and the vertical axis is volts. As a result of 100 charge/discharge tests, almost no deterioration was observed.

<Example 2> A negative electrode and a positive electrode are produced in the same manner as in Example 1. Next, the perfluorocarbon ion exchange membrane was cut into a size matching the diameters of the negative and positive electrodes, immersed in 2N hydrochloric acid, washed with water, and dried. This is used as a solid electrolyte. Using these materials, a positive electrode and a negative electrode were manufactured in the same manner as in Example 1, and a solid electrolyte battery was manufactured. In this case, the initial open-circuit potential at 25°C was 1340 mV. Thereafter, a charge/discharge test was performed every hour at 25° C. at a current density of 50 μA/d per electrode area. The results are shown in FIG. The horizontal axis is time and the vertical axis is volts. As a result of 100 charge/discharge tests, almost no deterioration was observed.

As mentioned above, in hydrogen solid electrolyte batteries, lead peroxide is used as the positive electrode, and by mixing carbon powder with it, it can be used as both a primary battery and a secondary battery.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a solid electrolyte battery provided for detailed explanation of the present invention. FIG. 2 is a discharge characteristic diagram of the solid hydrogen battery according to Example 1 of the present invention. FIG. 3 and FIG. 4 are charge/discharge characteristic diagrams of solid hydrogen batteries according to each embodiment of the present invention. I... Negative electrode, 2... Positive electrode, 3... Solid electrolyte, 4
... Current collector plate, 5 ... Lead wire, 6 ... Holding plate, 7
···Screw. Agent Patent attorney Aihiko Fuku (2 others) @/Figure νp Figure 2 t/h Figure 3 Ol 2 1/h Figure 4

Claims (1)

[Claims] 1. In a solid hydrogen battery, the negative electrode material is a hydrogen storage material that stores hydrogen as a metal hydride, the solid electrolyte is a hydrogen ion conductor, and the positive electrode material is a material that accepts hydrogen ions as a guest material. A solid hydrogen battery characterized by being made of a material mainly consisting of lead peroxide.