# US 11,444,335 B2 · High voltage rechargeable Zn—MnO2 battery

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- Number: US 11,444,335 B2
- Document ID: US11444335B2
- Status: Granted
- Kind: B2
- Application number: 16/627,284
- Filed: 2019-02-11
- Published: 2021-12-30
- Granted: 2022-09-13
- Earliest claimed: 2019-01-31
- Assignees: Tianjin University
- Applicants: Tianjin University
- Inventors: Wenbin Hu; Cheng Zhong; Bin Liu
- Web page: https://patentgrep.com/patent/US11444335B2

## CPC

- H01M 10/26: Selection of materials as electrolytes
- H01M 10/38: Construction or manufacture
- H01M 4/24: Electrodes for alkaline accumulators
- H01M 4/244: {Zinc electrodes}
- H01M 4/42: Alloys based on zinc
- H01M 4/50: of manganese
- H01M 50/409: Separators, membranes or diaphragms characterised by the material
- H01M 50/46: Separators, membranes or diaphragms characterised by their combination with electrodes
- H01M 10/0567: characterised by the additives
- H01M 2300/0005: Acid electrolytes
- H01M 2300/0014: Alkaline electrolytes
- H01M 2300/0088: Composites
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The invention discloses a high voltage rechargeable Zn—MnO2 battery. The structure of the Zn—MnO2 battery includes zinc electrode/alkaline electrolyte/ion exchange membrane/acid electrolyte/MnO2 electrode. The ion exchange membrane comprises a cation exchange membrane, an anion exchange membrane or a proton exchange membrane. According to the invention, by using a composite electrolyte system (alkaline electrolyte/ion exchange membrane/acid electrolyte), a high voltage rechargeable Zn—MnO2 battery is obtained. According to the invention, an open circuit voltage of up to 2.7V is obtained, greatly improving the discharge voltage, and at the same time increasing the discharge capacity and enabling cyclic charge and discharge. The invention is of great importance in science research, beneficial to society and economics.

## Claims

### Claim 1

A rechargeable Zn—MnO2 battery, wherein a structure of the Zn—MnO2 battery comprises
a zinc electrode;
an alkaline electrolyte comprising an alkaline liquid electrolyte, wherein the alkaline liquid electrolyte comprises a concentration of an alkali metal hydroxide from 200 g/L to 600 g/L;
an acid electrolyte comprising an acidic liquid electrolyte, wherein the acidic liquid electrolyte comprises an acid concentration of 50 g/L-300 g/L, and the acidic liquid electrolyte is an aqueous solution of 50 g/L-100 g/L sulfuric acid and 150 g/L-200 g/L manganese sulfate;
an ion exchange membrane, added between the acid electrolyte and the alkaline electrolyte to limit the contact between hydrogen ions and hydroxyl ions, thereby ensuring a normal operation of the rechargeable Zn—MnO2 battery; and
a MnO2 electrode in which MnO2 powder is mixed with a conductive agent and an additive, thus achieving an open circuit voltage greater than 2.45V.

### Claim 2 (depends on 1)

The rechargeable Zn—MnO2 battery according to claim 1, wherein the zinc electrode is prepared by using a zinc foil, a zinc paste or zinc powder.

### Claim 3 (depends on 1)

The rechargeable Zn—MnO2 battery according to claim 1, wherein the alkaline liquid electrolyte comprises a potassium hydroxide solution with an additive, and the additive comprises zinc oxide.

### Claim 4 (depends on 1)

The rechargeable Zn—MnO2 battery of claim 1, wherein said ion exchange membrane comprises a proton exchange membrane.

### Claim 5 (depends on 1)

The rechargeable Zn—MnO2 battery according to claim 1, wherein the acidic liquid electrolyte comprises a sulfuric acid solution with an additive, and the additive comprises manganese sulfate.

### Claim 6 (depends on 1)

The rechargeable Zn—MnO2 battery according to claim 1, wherein the MnO2 electrode comprises a MnO2 powder electrode or an electrodeposited MnO2 electrode.

### Claim 7 (depends on 1)

The rechargeable Zn—MnO2 battery according to claim 1, wherein the concentration of the alkali metal hydroxide in the alkali liquid electrolyte ranges from 300 g/L to 400 g/L and the acid concentration of the acidic liquid electrolyte ranges from 50 g/L to 100 g/L.

### Claim 8 (depends on 1)

The rechargeable Zn—MnO2 battery according to claim 1, wherein, in a discharge reaction of the rechargeable Zn—MnO2 battery, MnO2 molecules of the MnO2 electrode are converted from +4 valence to +2 valence, thus each of the MnO2 molecules releases two electrons, increasing an energy density of the MnO2 electrode.

### Claim 9 (depends on 7)

The rechargeable Zn—MnO2 battery according to claim 7, wherein an electrode reaction of the MnO2 electrode in the acidic electrolyte is: positive electrode reaction: MnO2+4H++2e—=Mn2+2H2O, and a standard electrode potential for the positive electrode reaction is 1.224 V; in the alkaline electrolyte, the negative electrode reaction: Zn+2OH—=ZnO+H2O+2e—, and a standard electrode potential of the Zn electrode is −1.215V.

### Claim 10 (depends on 1)

The rechargeable Zn—MnO2 battery according to claim 1, wherein the ion exchange membrane comprises a sulfonic acid-based cation exchange membrane.

### Claim 11 (depends on 1)

The rechargeable Zn—MnO2 battery according to claim 1, wherein the MnO2 electrode is prepared by uniformly mixing 8 g of MnO2 powder with 1 g of graphite powder and 1 g of polyvinylidene fluoride to produce a first mixture, adding the first mixture to 0.4 g of a 100 g/L sulfuric acid solution to produce a second mixture, stirring the second mixture, and drying the second mixture to produce the MnO2 electrode, thus the rechargeable Zn—MnO2 battery has an open circuit voltage above 2.6V, has a working platform voltage above 2.4V, and with a charging voltage under 3V, is configured to be cycled stably for more than 50 cycles.

### Claim 12 (depends on 1)

The rechargeable Zn—MnO2 battery according to claim 1, wherein the zinc electrode is prepared by adding 10 g of zinc powder into 4 g of lithium hydroxide solution with a mass fraction of 20 wt %, together with 0.04 g of sodium polyacrylate adhesive to produce a first mixture, evenly stirring the first mixture and letting the first mixture stand at room temperature for 12 hours to obtain the zinc electrode, thus the rechargeable Zn—MnO2 battery has an open circuit voltage above 2.6V, has a working platform voltage above 2.4V, and with a charging voltage under 3V, is configured to be cycled stably for more than 100 cycles.

### Claim 13 (depends on 1)

The rechargeable Zn—MnO2 battery according to claim 1, wherein the MnO2 electrode is prepared by dissolving 20 g of manganese sulfate monohydrate and 20 g of sulfuric acid in 100 mL of water, using a graphite sheet as a working electrode and a counter electrode, depositing, via a DC power source, at 1.8V for 3600 seconds thus producing an anode piece, and removing, rinsing, and drying the anode piece to produce the MnO2 electrode, thus the rechargeable Zn—MnO2 battery has an open circuit voltage above 2.6V, has a working platform voltage above 2.4V, and with a charging voltage under 3V, is configured to be cycled stably for more than 100 cycles.

### Claim 14 (depends on 1)

The rechargeable Zn—MnO2 battery according to claim 1, wherein the acidic liquid electrolyte is prepared by dissolving 10 g of sulfuric acid and 15 g of manganese sulfate monohydrate in 100 mL of water to obtain the acidic liquid electrolyte, thus the rechargeable Zn—MnO2 battery has an open circuit voltage above 2.6V, has a working platform voltage above 2.4V, and with a charging voltage under 3V, is configured to be cycled stably for more than 100 cycles.

### Claim 15 (depends on 1)

The rechargeable Zn—MnO2 battery according to claim 1, wherein the ion exchange membrane comprises a sulfonic acid based proton exchange membrane.

### Claim 16 (depends on 1)

The rechargeable Zn—MnO2 battery according to claim 1, wherein the zinc electrode is prepared by uniformly mixing 80 g of zinc powder, 10 g of graphite, 10 g of polyvinylidene fluoride, 4 mL of N-methylpyrrolidone to obtain a first mixture, and drying the first mixture to obtain a zinc powder electrode, thus the rechargeable Zn—MnO2 battery has an open circuit voltage above 2.7V, has a working platform voltage above 2.6V, and with a charging voltage under 3V, is configured to be cycled stably for more than 100 cycles.