Zinc electrode improvements

Patent metadata

Field	Value
Publication number	US-11670759-B2
Application number	US-202117375381-A
Country	US
Kind code	B2
Filing date	Jul 14, 2021
Priority date	Jul 19, 2019
Publication date	Jun 6, 2023
Grant date	Jun 6, 2023

Abstract

Disclosed are methods of making porous zinc electrodes. Taken together, the steps are: forming a mixture of water, a soluble compound that increases the viscosity of the mixture, an insoluble porogen, and metallic zinc powder; placing the mixture in a mold to form a sponge; optionally drying the sponge; placing the sponge in a metal mesh positioned to allow air flow through substantially all the openings in the mesh; heating the sponge in an inert atmosphere at a peak temperature of 200 to 420° C. to fuse the zinc particles to each other to form a sintered sponge; and heating the sintered sponge in an oxygen-containing atmosphere at a peak temperature of 420 to 700° C. to form ZnO on the surfaces of the sintered sponge. The heating steps burn out the porogen.

First claim

What is claimed is:

1. A method comprising:
forming a mixture comprising:
water;
a water-soluble compound that increases the viscosity of the mixture;
water-insoluble porogen particles; and
metallic zinc powder;

placing the mixture in a mold to form a sponge;
optionally drying the sponge;
heating the sponge in an inert atmosphere at a temperature that fuses the zinc particles to each other to form a sintered sponge; and
heating the sintered sponge in an oxygen-containing atmosphere at a temperature that forms ZnO on the surfaces of the sintered sponge;
wherein the heating steps burn out the porogen.

2. The method of claim 1 , wherein the mixture further comprises an organic liquid.

3. The method of claim 1 , wherein the water-soluble compound is a water-soluble carboxymethyl cellulose resin.

4. The method of claim 1 , wherein the porogen is corn starch.

5. The method of claim 1 , wherein the heating steps are performed with the sponge in a metal mesh positioned to allow air flow through substantially all the openings in the mesh.

6. The method of claim 5 ;
wherein the mesh is cylindrical in shape; and
wherein the mesh is placed horizontally on a substrate that touches the mesh at most on two lines along the length of the mesh.

7. The method of claim 1 , wherein heating the sponge in an inert atmosphere is performed at a peak temperature of 200 to 420° C.

8. The method of claim 1 , wherein heating the sintered sponge in an oxygen-containing atmosphere is performed at a peak temperature of 420 to 700° C.

9. A zinc electrode made by the method of claim 1 .

10. The zinc electrode of claim 9 , wherein the zinc electrode has a density of at least 1.0 g cm −3 .

11. The zinc electrode of claim 9 , wherein the zinc electrode comprises no more than 99 wt. % ZnO.

12. An electrochemical cell comprising:
an anode current collector;
the zinc electrode of claim 9 in electrical contact with the anode current collector;
an electrolyte;
a cathode current collector;
a cathode in electrical contact with the cathode current collector; and
a separator between the zinc electrode and the cathode.

13. A method comprising:
providing a sponge comprising zinc particles and porogen particles;
placing the sponge in a metal mesh positioned to allow air flow through substantially all the openings in the mesh;
heating the sponge in an inert atmosphere at a temperature that fuses the zinc particles to each other to form a sintered sponge; and
heating the sintered sponge in an oxygen-containing atmosphere at a temperature that forms ZnO on the surfaces of the sintered sponge;
wherein the heating steps burn out the porogen.

14. The method of claim 13 , wherein heating the sponge in an inert atmosphere is performed at a peak temperature of 200 to 420° C.

15. The method of claim 13 , wherein heating the sintered sponge in an oxygen-containing atmosphere is performed at a peak temperature of 420 to 700° C.

16. The method of claim 15 , wherein heating the sintered sponge produces a zinc electrode comprising no more than 99 wt. % ZnO.

17. A method comprising:
providing a sponge comprising zinc particles and porogen particles;
heating the sponge in an inert atmosphere at a peak temperature of 200 to 420° C. to fuse the zinc particles to each other to form a sintered sponge; and
heating the sintered sponge in an oxygen-containing atmosphere at a peak temperature of 420 to 700° C. to form ZnO on the surfaces of the sintered sponge;
wherein the heating steps burn out the porogen.

18. The method of claim 17 , wherein heating the sintered sponge produces a zinc electrode comprising no more than 99 wt. % ZnO.

19. The zinc electrode of claim 9 , wherein the zinc electrode has a density of at least 2.5 g cm −3 .

Assignees

• Us Gov Sec Navy

Inventors

• Hopkins Brandon J
• Parker Joseph F
• Long Jeffrey W
• Rolison Debra R

Classifications

• H01M10/24

  Alkaline accumulators · CPC title

• H01M4/0433

  Molding · CPC title

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/244

  Zinc electrodes · CPC title

• B22F3/1143

  involving an oxidation, reduction or reaction step · CPC title