Multi-element liquid metal battery

1. An electrochemical cell configured to exchange energy with an external device, the electrochemical cell comprising:

a negative electrode comprising at least a first active metal and a second active metal, wherein the first active metal is calcium and the second active metal is an alkali metal;

a positive electrode comprising one or more elements selected from the group consisting of Al, Si, Zn, Ga, Ge, Cd, In, Sn, Sb, Hg, Tl, Pb, Bi, Te, and Mg; and

an electrolyte comprising a cation of calcium and a cation of the alkali metal, the electrolyte configured to allow the cations of the calcium and the alkali metal to be transferred from the negative electrode to the positive electrode during discharging and to be transferred from the positive electrode to the negative electrode during charging,

wherein the electrolyte exists as a liquid phase and one or both of the negative electrode and the positive electrode exists as liquid or partially liquid phases at operating temperatures of the electrochemical cell.

2. The electrochemical cell of claim 1 , wherein the alkali metal is lithium.

3. The electrochemical cell of claim 1 , wherein the negative electrode, the positive electrode or both further includes a diluent.

4. The electrochemical cell of claim 3 , wherein the diluent is an alkaline earth metal.

5. The electrochemical cell of claim 4 , wherein the alkaline earth metal is magnesium.

6. The electrochemical cell of claim 1 , wherein the electrolyte includes a halide salt of the alkali metal and a halide salt of calcium.

7. The electrochemical cell of claim 1 , wherein the electrolyte includes lithium chloride.

8. The electrochemical cell of claim 1 , wherein the electrolyte includes lithium chloride, potassium chloride, and calcium chloride.

9. The electrochemical cell of claim 1 , wherein the negative electrode includes a calcium-magnesium-lithium alloy and the electrolyte includes a lithium salt and a calcium salt.

10. The electrochemical cell of claim 9 , wherein the lithium salt and calcium salt are each independently selected from the group consisting of halides, oxides, chalcogenides, perchlorates, sulfates, sulfites, carbonates, nitrates, nitrites, hydroxides and combinations thereof.

11. The electrochemical cell of claim 1 , wherein the positive electrode comprises one or more elements selected from the group consisting of bismuth, lead, antimony, zinc, tin, and magnesium.

12. A method of exchanging electrical energy with an external circuit, the method comprising:

connecting the electrochemical cell of claim 1 to the external circuit; and

operating the external circuit so as to drive transfer of the calcium and the alkali metal between the positive electrode and the negative electrode.

13. The method of claim 12 , wherein the alkali metal is lithium.

14. The method of claim 12 , wherein the negative electrode, the positive electrode or both further includes a diluent.

15. The method of claim 14 , wherein the diluent is an alkaline earth metal.

16. The method of claim 15 , wherein the alkaline earth metal is magnesium.

17. The method of claim 12 , wherein the electrolyte includes a halide salt of the alkali metal and a halide salt of calcium.

18. The method of claim 17 , wherein the electrolyte includes lithium chloride, potassium chloride, and calcium chloride.

19. The method of claim 12 , further comprising forming a calcium-magnesium-lithium alloy in the negative electrode when the cell is in operation.