Electrolyte recovery
The invention provides a method of recovering a lithium electrolyte salt from a used electrolyte, the method comprising: contacting a used electrolyte comprising a lithium electrolyte salt and electrolyte solvent with a polar aprotic solvent to produce a solution comprising the lithium electrolyte salt, the electrolyte solvent and the polar aprotic solvent, wherein at least one of the electrolyte solvent and the polar aprotic solvent comprises carbonate solvent, combining the solution with a precipitation solvent in which the lithium electrolyte salt is poorly soluble; precipitating a precipitated composition comprising the lithium electrolyte salt solvated by the carbonate solvent from a solvent mixture comprising the polar aprotic solvent, the precipitation solvent and the electrolyte solvent, wherein the precipitated composition precipitates as a solid or as a liquid; and separating the precipitated composition from the solvent mixture.
1 . A method of recovering a lithium electrolyte salt from a used electrolyte, the method comprising:
contacting a used electrolyte comprising a first lithium electrolyte salt and an electrolyte solvent with a polar aprotic solvent to produce a solution comprising the first lithium electrolyte salt, the electrolyte solvent, and the polar aprotic solvent, wherein at least one of the electrolyte solvent and the polar aprotic solvent comprises carbonate solvent;
combining the solution with a precipitation solvent in which the first lithium electrolyte salt is poorly soluble;
precipitating a precipitated composition comprising the first lithium electrolyte salt solvated by the carbonate solvent from a solvent mixture comprising the polar aprotic solvent, the precipitation solvent, and the electrolyte solvent, wherein the precipitated composition precipitates as a solid or as a liquid; and
separating the precipitated composition from the solvent mixture;
wherein the used electrolyte has been placed in an electrochemical energy storage device prior to contacting the used electrolyte with the polar aprotic solvent.
2 . The method according to claim 1 , wherein the precipitated composition precipitates as a solid.
3 . The method according to claim 1 , wherein the first lithium electrolyte salt is LiPF 6 .
4 . The method according to claim 1 , wherein both the electrolyte solvent and the polar aprotic solvent comprise carbonate solvent.
5 . The method according to claim 1 , wherein at least one of the electrolyte solvent and the polar aprotic solvent comprises ethylene carbonate.
6 . The method according to claim 5 , wherein the electrolyte solvent comprises ethylene carbonate, and wherein the polar aprotic solvent comprises at least one selected from dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate.
7 . The method according to claim 5 , wherein the precipitated composition comprises Li (ethylene carbonate) n PF 6 , wherein the average value of n is in the range of about 4 to 5.
8 . The method according to claim 1 , wherein the used electrolyte is present in the electrochemical energy storage device, or a component or derivative thereof, and wherein contacting the used electrolyte with the polar aprotic solvent comprises extracting the electrochemical energy storage device, or the component or derivative thereof, with the polar aprotic solvent.
9 . The method according to claim 1 , wherein the precipitation solvent comprises a hydrocarbon solvent or a chlorinated solvent.
10 . The method according to claim 1 , wherein the precipitation solvent has a normal boiling point of below 120° C.
11 . The method according to claim 1 , wherein the combining and the precipitating are conducted at temperatures below 50° C.
12 . The method according to claim 1 , wherein precipitating the precipitated composition comprises cooling the solvent mixture to a temperature below 10° C.
13 . The method according to claim 1 , further comprising concentrating the solution before combining the solution with the precipitation solvent.
14 . The method according to claim 1 , further comprising extracting the solution with an at least partially immiscible non-polar solvent and separating the solution from an extractant liquid phase comprising the non-polar solvent before combining the solution with the precipitation solvent.
15 . A method of recycling a lithium electrolyte salt from an electrochemical energy storage device, the method comprising:
providing an electrochemical energy storage device, or a component or derivative thereof, comprising an electrolyte comprising a first lithium electrolyte salt and an electrolyte solvent;
extracting the electrochemical energy storage device, or the component or derivative thereof, with a polar aprotic solvent to produce a solution comprising the first lithium electrolyte salt, the electrolyte solvent, and the polar aprotic solvent, wherein at least one of the electrolyte solvent and the polar aprotic solvent comprises a carbonate solvent;
combining the solution with a precipitation solvent in which the first lithium electrolyte salt is poorly soluble;
precipitating a precipitated composition comprising the first lithium electrolyte salt solvated by the carbonate solvent from a solvent mixture comprising the polar aprotic solvent, the precipitation solvent, and the electrolyte solvent, wherein the precipitated composition precipitates as a solid or as a liquid; and
separating the precipitated composition from the solvent mixture;
wherein the used electrolyte has been placed in an electrochemical energy storage device prior to contacting the used electrolyte with the polar aprotic solvent.
16 . The method according to claim 15 , wherein the precipitated composition precipitates a solid.
17 . The method according to claim 15 , further comprising dissolving the precipitated composition in an electrolyte solvent comprising carbonate to produce an electrolyte for an electrochemical energy storage device.
18 . A method of producing an electrolyte for an electrochemical energy storage device, the method comprising:
contacting used electrolyte comprising a first lithium electrolyte salt and a first electrolyte solvent with a polar aprotic solvent to produce a solution comprising the first lithium electrolyte salt, the first electrolyte solvent, and the polar aprotic solvent, wherein at least one of the first electrolyte solvent and the polar aprotic solvent comprises a first carbonate solvent;
combining the solution with a precipitation solvent in which the first lithium electrolyte salt is poorly soluble;
precipitating a precipitated composition comprising the first lithium electrolyte salt solvated by the first carbonate solvent from a solvent mixture comprising the polar aprotic solvent, the precipitation solvent, and the first electrolyte solvent, wherein the precipitated composition precipitates as a solid or as a liquid;
separating the precipitated composition from the solvent mixture; and
dissolving the precipitated composition in a second electrolyte solvent comprising a second carbonate solvent to produce an electrolyte for an electrochemical energy storage device;
wherein the used electrolyte has been placed in an electrochemical energy storage device prior to contacting the used electrolyte with the polar aprotic solvent.
19 . The method according to claim 18 , wherein the precipitated composition precipitates as a solid.
20 . The method according to claim 1 , wherein, prior to contacting the used electrolyte with the polar aprotic solvent, the electrochemical energy storage device, or a component or derivative thereof, is dismantled or physically broken up.
21 . The method according to claim 20 , wherein the electrochemical energy storage device, or the component or derivative thereof, is crushed, comminuted, or shredded.
22 . The method according to claim 1 , wherein the solution is subjected to one or more processing steps after contacting the used electrolyte with the polar aprotic solvent and before combining the solution with the precipitation solvent.
23 . The method according to claim 22 , wherein the one or more processing steps comprise removing impurities from the solution prior to precipitation of the first lithium electrolyte salt.
24 . The method of claim 15 , wherein the electrochemical energy storage device, or a component or derivative thereof comprises a crushed, comminuted, or shredded electrochemical energy storage device.
25 . The method according to claim 15 , further comprising removing impurities from the solution prior to precipitating the first lithium electrolyte salt.
26 . The method according to claim 18 , further comprising removing impurities from the solution prior to precipitating the first lithium electrolyte salt.