Electrolyte system for metal-air batteries and methods of use thereof

1. A metal-air cell comprising:

an electrolyte chamber comprising circulating alkaline electrolyte, wherein said alkaline electrolyte comprises submicron particles;

an inlet for introducing said electrolyte into said electrolyte chamber;

an outlet for removing said electrolyte from said electrolyte chamber; and

optionally an ultrasonic source;

wherein ultrasonic vibration is optionally applied to said electrolyte; and

wherein said submicron particles, said ultrasonic vibration or a combination thereof avoid the formation of or remove or reduce the size of or reduce the concentration of metal-hydroxide precipitate formed in said alkaline electrolyte solution of said metal-air electrochemical cell during an electrochemical reaction and wherein said submicron particles are not seed particles, and wherein said submicron particles comprise Al 2 O 3 , TiO 2 , ZrO 2 or a combination thereof and wherein the average diameter of said submicron particles is between 5 nm to 1000 nm.

2. The metal-air cell of claim 1 , wherein said metal-air cell is an Al-air cell.

3. The metal-air cell of claim 1 , wherein said alkaline electrolyte comprises sodium hydroxide or potassium hydroxide.

4. The metal-air cell of claim 1 , wherein said particles are added in an amount of between 0.1-1.5 wt % from the total amount of said electrolyte used.

5. The metal-air cell of claim 1 , wherein said ultrasonic source generates ultrasonic energy in said alkaline electrolyte.

6. The metal-air cell of claim 1 , wherein a portion of said ultrasonic source is located within said electrolyte chamber, or surrounds said electrolyte chamber or a combination thereof.

7. A metal-air cell comprising:

an electrolyte chamber comprising circulating alkaline electrolyte, wherein said alkaline electrolyte comprises submicron particles;

an inlet for introducing said electrolyte into said electrolyte chamber;

an outlet for removing said electrolyte from said electrolyte chamber; and

optionally an ultrasonic source;

wherein ultrasonic vibration is optionally applied to said electrolyte; and wherein said submicron particles, said ultrasonic vibration or a combination thereof avoid the formation of or remove or reduce the size of or reduce the concentration of metal-hydroxide precipitate formed in said alkaline electrolyte solution of said metal-air electrochemical cell during an electrochemical reaction and wherein said submicron particles are not seed particles, and wherein said submicron particles comprise Al 2 O 3 , TiO 2 , ZrO 2 or a combination thereof and, wherein the average diameter of said submicron particles is between 1 nm to 100 nm.

8. The metal-air cell of claim 1 , wherein the D50 for said submicron particles is in a range between 10 nm to 100 nm.

9. The metal-air cell of claim 1 , said submicron particles are added to said electrolyte prior to battery discharge.

10. The metal-air cell of claim 1 , wherein said submicron particles are added to said electrolyte during battery discharge.

11. The metal-air cell of claim 1 , wherein said cell comprises one cathode and one anode.

12. The metal-air cell of claim 1 , wherein said cell comprises two cathodes and one anode.

13. The metal-air cell of claim 1 , wherein said cell is used in electric vehicles, in unmanned aerial vehicles (UAV), in reserve and in emergency power supplies.

14. A method of avoiding the formation of or of removing or of reducing the concentration of metal-hydroxide precipitate formed in an alkaline electrolyte solution of a metal-air electrochemical cell according to claim 1 during an electrochemical reaction, said method comprising adding submicron particles to said solution or applying ultrasonic vibration to said solution or a combination thereof.

15. The method of claim 14 , wherein said metal-air electrochemical cell is an Al-air cell.

16. The method of claim 15 , wherein said metal hydroxide precipitate comprises Al(OH) 3 .

17. The method of claim 14 , wherein said alkaline electrolyte solution comprises sodium hydroxide or potassium hydroxide.

18. The method of claim 14 , wherein said electrolyte solution is subjected to circulation.

19. The method of claim 14 , wherein said submicron particles comprises Al 2 O 3 , TiO 2 , ZrO 2 or a combination thereof.

20. The method of claim 14 , wherein said particles are added in an amount of between 0.1-1.5 wt % from the total amount of said electrolyte used.

21. A method of increasing the electrolyte utilization coefficient of an alkaline electrolyte in a metal-air electrochemical cell according to claim 1 , comprising adding submicron particles to said electrolyte or applying ultrasonic vibration to said electrolyte or a combination thereof.

22. The method of claim 21 , wherein said metal-air cell is an Al-air cell.

23. The method of claim 22 , wherein said increasing the utilization coefficient of said electrolyte is achieved by reducing the concentration of Al(OH) 3 precipitate in said electrolyte.

24. The method of claim 21 , wherein said alkaline electrolyte comprises sodium hydroxide or potassium hydroxide.

25. The method of claim 21 , wherein said electrolyte is subjected to circulation.

26. The method of claim 21 , wherein said submicron particles comprises Al 2 O 3 , TiO 2 , ZrO 2 or combination thereof.

27. The method of claim 21 , wherein said particles are added in an amount of between 0.4-0.6 wt % from the total amount of said electrolyte used.

28. The method of claim 21 , wherein said method increases the electrolyte utilization coefficient up to a value ranging between 0.6 and 0.7Ah/ml.