Low temperature lithium production
A method and electrolysis cell for producing lithium metal at a low temperature. The method includes combining (i) acetonitrile and (ii) a cation bis(trihaloalkylsulfonyl)imide, cation bis(trihalosulfonyl)imidic acid, a cation bis(trihaloalkylsulfonyl)amide, or cation bis(trihaloalkylsulfonyl)amidic acid in a weight ratio of (i) to (ii) about 100:1 to about 5:1 to provide a non-aqueous electrolyte composition. A lithium compound selected from the group consisting of LiOH, Li 2 O and Li 2 CO 3 is dissolved in the electrolyte composition to provide a lithium doped electrolyte composition. Power is applied to the electrolyte composition to form lithium metal on a cathode of an electrolysis cell. The lithium metal separated from the cathode has a purity of at least about 95 wt. %.
1. A method of producing lithium metal in an electrolysis cell, the method comprising the steps of:
combining (i) acetonitrile and (ii) a cation bis(trihaloalkylsulfonyl)imide, a cation bis(trihalo-sulfonyl)imidic acid, a cation bis(trihaloalkylsulfonyl)amide, or a cation bis(trihaloalkylsulfonyl)amidic acid to provide a non-aqueous electrolyte composition,
dissolving a lithium compound selected from the group consisting of LiOH, Li 2 and Li 2 CO 3 in the non-aqueous electrolyte composition to provide a doped lithium electrolyte composition,
applying power to the electrolysis cell to form lithium metal on a cathode of an electrolysis cell, and
separating lithium metal from the cathode.
2. The method of claim 1 , wherein the doped lithium electrolyte composition further comprises a zwitterion or internal salt compound.
3. The method of claim 2 , wherein the zwitterion comprises a (carboxyalkyl)trialkyl ammonium compound.
4. The method of claim 1 , wherein the weight ratio of (i) to (ii) of the non-aqueous electrolyte composition is about 60:1 to 5:1.
5. The method of claim 4 , wherein a weight ratio of non-aqueous electrolyte composition to lithium compound ranges from about 5:1 to about 2:3.
6. The method of claim 5 , wherein a weight ratio of non-aqueous electrolyte composition to lithium compound ranges from about 3:1 to about 3:4.
7. The method of claim 1 , wherein the doped lithium electrolyte composition is at a temperature ranging from about 0° to less than about 180° C.
8. The method of claim 1 , wherein the doped lithium electrolyte composition is at a temperature ranging from about 0° to less than about 100° C.
9. The method of claim 1 , wherein the doped lithium electrolyte composition is at a temperature ranging from about 15° to less than about 81° C.
10. The method of claim 1 , wherein the electrolysis cell contains a cover gas above the doped lithium electrolyte composition.
11. The method of claim 1 , wherein the electrolysis cell comprises an anode compartment, a cathode compartment and a separator between the anode compartment and the cathode compartment.
12. The method of claim 11 , wherein the separator is selected from the group consisting of a fritted glass separator, a microporous membrane, and a salt bridge.
13. The method of claim 1 , wherein the cation is selected from the group consisting of a phosphonium ion, a sulfonium ion, an ammonium ion, an imidazolium ion, a piperidinium ion, a pyridinium ion and a pyrrolidinium ion.
14. The method of claim 1 , wherein the cation is selected from the group consisting of an alkali metal, an alkaline earth metal, a metalloid, a transition metal, and a lanthanide.
15. The method of claim 1 , wherein the halo ion is a fluoride ion.
16. The method of claim 1 , wherein the alkyl group is a methyl group.
17. The method of claim 1 , wherein power is applied to the anode and cathode at a current density ranging from about 0.1 mA/cm 2 to about 2.5 mA/cm 2 .
18. An electrolysis cell for producing lithium metal at a temperature comprising:
a cathode compartment comprising a cathode,
an anode compartment comprising an anode,
a separator between the anode compartment and the cathode compartment,
a non-aqueous electrolyte composition in the anode and cathode compartments comprising (i) acetonitrile and (ii) a cation bis(trihaloalkylsulfonyl)imide, a cation bis(trihalosulfonyl)imidic acid, a cation bis(trihaloalkylsulfonyl)amide, or a cation bis(trihaloalkylsulfonyl)amidic acid, wherein the electrolyte composition further comprises a lithium compound selected from the group consisting of LiOH, Li 2 O and Li 2 CO 3 dissolved in the electrolyte composition, and wherein the separator is selected from the group consisting of a fritted glass separator, a microporous membrane, and a salt bridge,
whereby power applied to the anode and cathode forms lithium metal on the cathode of the electrolysis cell with a lithium metal purity of greater than 95 wt. %.
19. The electrolysis cell of claim 18 , wherein a weight ratio of non-aqueous electrolyte composition to lithium compound ranges from about 5:1 to about 2:3.
20. The electrolysis cell of claim 18 , wherein the electrolyte composition further comprises a (carboxyalkyl)trialkyl ammonium compound.
21. The electrolysis cell of claim 18 , wherein the cation is selected from the group consisting of a phosphonium ion, a sulfonium ion, an ammonium ion, an imidazolium ion, a piperidinium ion, a pyridinium ion, and a pyrrolidinium ion.
22. The electrolysis cell of claim 18 , wherein the cation is selected from the group consisting of an alkali metal, an alkaline earth metal, a metalloid, a transition metal, and a lanthanide.
23. The electrolysis cell of claim 18 , wherein the halo ion is a fluoride ion.
24. The electrolysis cell of claim 18 , wherein the alkyl group is a methyl group.
25. The electrolysis cell of claim 18 , wherein the electrolysis cell temperature is below about 180° C.
26. The method of claim 1 , wherein the lithium metal on the cathode has a purity of at least about 97 wt. %.