Synthesis of alkali metal-based phosphorous compounds using a lower pressure

1. A method for synthesizing an alkali metal-based phosphorous compound, the method comprising:

contacting an elemental alkali metal with elemental phosphorous to create a mixture; and

applying a total pressure of less than 20 gigapascals to the mixture for forming the alkali metal-based phosphorous compound

wherein the pressure is applied to the mixture at about room temperature.

2. The method as recited in claim 1 , wherein the pressure is applied without applying heat to the mixture.

3. The method as recited in claim 1 , comprising selecting the pressure in order to form an alkali metal-based phosphorous compound having a predefined crystal structure.

4. The method as recited in claim 1 , wherein the formed alkali metal-based phosphorous compound has a face-centered cubic crystal structure.

5. The method as recited in claim 1 , wherein the pressure is less than about 10 gigapascals.

6. The method as recited in claim 1 , wherein the pressure is less than about 5 gigapascals.

7. The method as recited in claim 6 , wherein the formed alkali metal-based phosphorous compound has a first crystal structure; and

further comprising applying a second pressure greater than 5 gigapascals to the formed alkali metal-based phosphorous compound for causing a phase transition to a second crystal structure that is different than the first crystal structure.

8. The method as recited in claim 6 , wherein the formed alkali metal-based phosphorous compound has a hexagonal crystal structure.

9. The method of claim 8 , further comprising applying a second pressure greater than 5 gigapascals to the formed alkali metal-based phosphorous compound for causing a phase transition to a face-centered cubic crystal structure.

10. The method of claim 9 , wherein the formed alkali metal-based phosphorous compound maintains the face-centered cubic crystal structure after release of the applied second pressure.

11. The method as recited in claim 1 , wherein the pressure is less than about 2 gigapascals and greater than atmospheric pressure.

12. The method as recited in claim 1 , wherein the elemental alkali metal is selected from the group consisting of: lithium, potassium, and sodium.

13. The method as recited in claim 1 , wherein the elemental alkali metal and the elemental phosphorous are each in powder form.

14. A method for synthesizing an alkali metal-based phosphorous compound, the method comprising,

contacting an elemental alkali metal with elemental phosphorous to create a mixture; and

applying a pressure of less than 20 gigapascals to the mixture for forming the alkali metal-based phosphorous compound,

wherein the formed alkali metal-based phosphorous compound comprises a ratio of elemental alkali metal (A) to elemental phosphorous (P), wherein the ratio of A to P increases with increasing applied pressure during the contacting.

15. The method as recited in claim 1 , wherein the formed alkali metal-based phosphorous compound is Li 3 P.

16. The method as recited in claim 1 , wherein the formed alkali metal-based phosphorous compound is Na 3 P.

17. A system comprising:

a mixture of an elemental alkali metal and an elemental phosphorous; and

a device for applying pressure to the mixture at about room temperature, wherein the device is configured to apply a pressure less than 20 gigapascals to the mixture,

wherein the device includes a diamond anvil cell.

18. A system as recited in claim 17 , wherein the pressure is less than about 5 gigapascals and greater than atmospheric pressure.

19. A system as recited in claim 17 , wherein the pressure is less than about 2 gigapascals and greater than atmospheric pressure.

20. A system as recited in claim 17 , wherein the system does not include added heat.