# US 4,397,925 A · Alkaline battery with reducing agents in the electrolyte

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- Number: US 4,397,925 A
- Document ID: US4397925A
- Status: Granted
- Kind: A
- Application number: 06/311,537
- Filed: 1981-10-15
- Granted: 1983-08-09
- Earliest claimed: 1981-10-15
- Assignees: Ray-O-Vac Corporation
- Inventors: El-Sayed A. Magahed
- Web page: https://patentgrep.com/patent/US4397925A

## CPC

- H01M 10/26: Selection of materials as electrolytes
- H01M 4/36: Selection of substances as active materials, active masses, active liquids
- H01M 6/50: Methods or arrangements for servicing or maintenance, e.g. for maintaining operating temperature (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569)
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

An alkaline cell containing an effective amount of an electrolyte soluble reducing agent of alkali metal borohydrides, quaternary ammonium borohydrides, complex aluminum hydrides or hydrazine.

## Claims

### Claim 1

An electrochemical cell having a stable, desirable, open circuit voltage comprising an active metal anode, an aqueous alkaline electrolyte, a suitable separator and a cathode containing at least one reducible oxidic specie dischargeable over the useful life of said cathode against said active metal anode at both an undesirable high voltage and a desirable lower voltage, said cell being characterized by having an effective amount of an electrolyte-soluble reducing agent selected from the group consisting of alkali metal borohydrides, quaternary ammonium borohydrides, complex aluminum hydrides and hydrazine present in said cell and available to said electrolyte at the time of cell closure.

### Claim 2 (depends on 1)

An electrochemical cell as in claim 1 wherein said electrolyte-soluble reducing agent is in said electrolyte at the time of cell closure.

### Claim 3 (depends on 1)

An electrochemical cell as in claim 1 wherein said electrolyte-soluble reducing agent is associated with said separator at the time of cell closure.

### Claim 4 (depends on 3)

An electrochemical cell as in claim 3 wherein said electrolyte-soluble reducing agent is associated with said active metal anode at the time of cell closure.

### Claim 5 (depends on 1)

An electrochemical cell as in claim 1 wherein said reducing agent is present in said electrolyte in an amount sufficient to reduce about 0.1% to about 10% of said reducible oxidic specie.

### Claim 6 (depends on 1)

An electrochemical cell as in claim 1 wherein said reducing agent is an alkali metal borohydride.

### Claim 7 (depends on 1)

An electrochemical cell as in claim 1 wherein said active metal anode is zinc.

### Claim 8 (depends on 7)

An electrochemical cell as in claim 7 wherein the cathode associated with zinc contains divalent silver oxide.

### Claim 9 (depends on 8)

An electrochemical cell as in claim 8 wherein the cathode assembled into a cell with electrolyte and a zinc anode is essentially pure divalent silver oxide.

### Claim 10 (depends on 9)

An electrochemical cell as in claim 9 wherein the electrolyte at cell closure contains an alkali metal borohydride.

### Claim 11 (depends on 1)

An electrochemical cell as in claim 1 wherein the cathode contains mercuric oxide and, as said at least one reducible oxidic species, .beta. manganese dioxide.

### Claim 12 (depends on 11)

An electrochemical cell as in claim 11 wherein the electrolyte associated with said cathode contains an alkali metal borohydride at the time of cell closure.

### Claim 13 (depends on 1)

An electrochemical cell as in claim 1 wherein the cathode is a mixed material selected from the group consisting of AgO--Ag.sub.2 O blends containing about 5 to about 98.5, weight percent AgO, permanganate Ag.sub.2 O blends containing about 5 to about 95 weight percent Ag.sub.2 O and MnO.sub.2 --Ag.sub.2 O blends containing about 10 to about 95 percent by weight MnO.sub.2.

### Claim 14

A process for stabilizing the voltage of an electrochemical cell having an active metal anode, an aqueous alkaline electrolyte, a suitable separator and a cathode containing at least one reducible oxidic specie dischargeable over the useful life of said cathode against said active metal anode at both an undesirable high voltage and a desirable lower voltage, said process comprising assembling said cell components and including in said cell and available to said electrolyte at the time of cell closure an effective amount of an electrolyte-soluble reducing agent selected from the group consisting of alkali metal borohydrides, quaternary ammonium borohydrides, complex aluminum hydrides and hydrazine.

### Claim 15 (depends on 14)

A process as in claim 14 wherein an alkali metal borohydride is included in said electrolyte at the time of cell closure.