Redox shuttle additives for lithium-ion batteries
An electro lye includes a compound of Formula I or IA: where each instance of R 1 is independently H, alkyl, alkoxy, alkenyl, aryl, heteroaryl, or cycloalkyl; each instance of R 2 is independently H, alkyl, alkoxy, alkenyl, aryl, heteroaryl, or cycloalkyl; each instance of R 3 is independently H, alkyl, alkenyl, aryl, or cycloalkyl; each instance of R 4 is independently H, halogen, CN, NO 2 , phosphate, alkyl, alkenyl, aryl, heteroaryl, or cycloalkyl; x is 1, 2, 3, 4, or 5; y is 1 or 2; and z is 0, 1, 2, 3, or 4.
1. An electrolyte comprising:
an alkali metal salt;
a polar aprotic solvent; and
a redox shuttle;
wherein:
the redox shuttle comprises a compound represented by Formula IB:
wherein:
each instance of R 1 is independently H, alkyl, alkoxy, alkenyl, heteroaryl, or cycloalkyl;
each instance of R 2 is independently H, alkyl, alkoxy, alkenyl, heteroaryl, or cycloalkyl; and
each instance of R 3 is independently H, alkyl, alkenyl, awl, or cycloalkyl;
or
a combination of any two or more thereof.
2. The electrolyte of claim 1 , wherein the redox shuttle has a redox potential of from 4 V to 5 V in the electrolyte.
3. The electrolyte of claim 1 , wherein a concentration of the redox shuttle in the electrolyte is from 0.0005 wt % to 50 wt %.
4. The electrolyte of claim 1 , wherein the alkali metal salt is a lithium salt.
5. An electrochemical device comprising a cathode, an anode, and the electrolyte of claim 1 .
6. A method of preparing an electrolyte comprising:
combining an alkali metal salt and redox shuttle in a polar aprotic solvent;
wherein:
the redox shuttle comprises a compound represented by Formula IB:
wherein:
each instance of R 1 is independently H, alkyl, alkoxy, alkenyl, heteroaryl, or cycloalkyl;
each instance of R 2 is independently H, alkyl, alkoxy, alkenyl, heteroaryl, or cycloalkyl; and
each instance of R 3 is independently H, alkyl, alkenyl, awl, or cycloalkyl;
or
a combination of any two or more thereof.
7. An electrolyte comprising:
an alkali metal salt;
a polar aprotic solvent; and
a redox shuttle;
wherein:
the redox shuttle comprises a compound represented by Formula IIB:
wherein:
each instance of R 1 is independently H, alkyl, alkoxy, alkenyl, aryl, heteroaryl, or cycloalkyl;
each instance of R 2 is independently H, alkyl, alkoxy, alkenyl, aryl, heteroaryl, or cycloalkyl; and
each instance of R 3 is independently H, alkyl, alkenyl, aryl, or cycloalkyl.
8. The electrolyte of claim 7 , wherein the redox shuttle has a redox potential of from 4 V to 5 V in the electrolyte.
9. The electrolyte of claim 7 , wherein the redox shuttle is represented by Formula II-1, II-2, II-3, II-4, II-5, or II-6:
10. The electrolyte of claim 7 , wherein a concentration of the redox shuttle in the electrolyte is from 0.0005 wt % to 50 wt %.
11. The electrolyte of claim 7 , wherein the alkali metal salt is a lithium salt.
12. An electrochemical device comprising a cathode, an anode, and an electrolyte, the electrolyte comprising:
an alkali metal salt;
a polar aprotic solvent; and
a redox shuttle;
wherein:
the redox shuttle comprises a compound represented by Formula IIB:
wherein:
each instance of R 1 is independently H, alkyl, alkoxy, alkenyl, aryl, heteroaryl, or cycloalkyl;
each instance of R 2 is independently H, alkyl, alkoxy, alkenyl, aryl, heteroaryl, or cycloalkyl; and
each instance of R 3 is independently H, alkyl, alkenyl, aryl, or cycloalkyl.