Redox shuttles for lithium ion batteries
An electrolyte may include compounds of general Formula IVA or IVB. where, R 8 , R 9 , R 10 , and R 11 are each independently selected from H, F, Cl, Br, CN, NO 2 , alkyl, haloalkyl, and alkoxy groups; X and Y are each independently O, S, N, or P; and Z′ is a linkage between X and Y, and at least one of R 8 , R 9 , R 10 , and R 11 is other than H.
1. An electrolyte comprising:
a redox shuttle comprising a compound of Formula IVA or IVB:
R 9 and R 11 are each independently H, F, Cl, Br, CN, NO 2 , alkyl, haloalkyl, or alkoxy groups;
R 8 and R 10 are each independently alkyl;
X and Y are each independently O, S, N, or P; and
Z′ is a linkage between X and Y.
2. The electrolyte of claim 1 , wherein X and Y are O.
3. The electrolyte of claim 1 , wherein: Z′ is CH 2 , CH 2 CH 2 , CH 2 CH 2 CH 2 , CH 2 CH 2 CH 2 CH 2 , CH 2 CH 2 CH 2 CH 2 CH 2 , CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 , CH(CH 3 )CH 2 , CH(C 3 )(CH 2 )CH 2 , CH(CH 3 )CH(CH 3 ), CHCH, CCl 2 , C 2 , CF 2 , CH(Cl)CH(Cl), CH(Br)CH(Br), CH(F)CH(F), CH 2 (CF 2 )CH 2 , CH 2 N(Me)CH 2 , CH 2 OCH 2 CH 2 OCH 2 , CH 2 CH 2 OCH 2 OCH 2 CH 2 ; CH 2 CH 2 OCH 2 CH 2 OCH 2 , or CH 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 .
4. The electrolyte of claim 1 , wherein at least two of R 8 , R 9 , R 10 , and R 11 are independently tertiary alkyl groups.
5. The electrolyte of claim 1 , wherein
X and Y are O; and
Z′ is CH 2 , CH 2 CH 2 , or CHCH.
6. The electrolyte of claim 1 , wherein:
R 8 and R 10 are tert-butyl;
R 9 and R 11 are each independently H, F, Cl, or Br;
X and Y are O; and
Z′ is CH 2 or CHCH.
7. The electrolyte of claim 1 , wherein the compound comprises 5,7-di-tert-butyl-2,3-dibromo-1,4-benzodioxin; 5,7-di-tert-butyl-1,4-benzodioxin; or 4,6-di-tert-butyl-1,3-benzodioxole.
8. The electrolyte of claim 1 , wherein the redox shuttle has a redox potential of from 3 V to 5 V in the electrolyte.
9. The electrolyte of claim 1 , wherein the redox shuttle is present in the electrolyte from 0.0005 wt % to 50 wt %.
10. The electrolyte of claim 1 , further comprising an alkali metal salt.
11. The electrolyte of claim 10 , wherein the alkali metal salt comprises Li[B(C 2 O 4 ) 2 ]; Li[BF 2 (C 2 O 4 )]; LiClO 4 ; LiBF 4 ; LiAsF 6 ; LiPF 6 ; Li[CF 3 S 0 3 ]; Li[N(CF 3 S 0 2 ) 2 ]; Li[C(CF 3 SO 2 ) 3 ]; LiN(SO 2 C 2 F 5 ) 2 ; or a lithium alkyl fluorophosphate.
12. The electrolyte of claim 1 , wherein further comprising a polar aprotic solvent.
13. The electrolyte of claim 12 , wherein the polar aprotic solvent comprises ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dimethyl ether, or γ-butyrolactone.
14. The electrolyte of claim 1 which is substantially non-aqueous.
15. An electrochemical device comprising
a cathode
an anode; and
an electrolyte comprising a compound of Formula IVA or IVB;
the compound of Formula IVA or IVB is:
R 9 and R 11 are each independently H, F, Cl, Br, CN, NO 2 , alkyl, haloalkyl, or alkoxy groups;
R 8 and R 10 are each independently alkyl;
X and Y are each independently O, S, N, or P; and
Z′ is a linkage between X and Y.
16. The electrochemical device of claim 15 , wherein X and Y are O.
17. The electrochemical device of claim 15 , wherein at least two of R 8 , R 9 , R 11 , and R 11 are independently tertiary alkyl groups.
18. The electrochemical device of claim 15 , wherein: Z′ is CH 2 , CH 2 CH 2 , CH 2 CH 2 CH 2 , CH 2 CH 2 CH 2 CH 2 , CH 2 CH 2 CH 2 CH 2 CH 2 , CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 , CH(CH 3 )CH 2 , CH(CH 3 )(CH 2 )CH 2 , CH(CH 3 )CH(CH 3 ), CHCH, CCl 2 , CBr 2 , CF 2 , CH(Cl)CH(Cl), CH(Br)CH(Br), CH(F)CH(F), CH 2 (CF 2 )CH 2 , CH 2 N(Me)CH 2 , CH 2 OCH 2 CH 2 OCH 2 , CH 2 CH 2 OCH 2 OCH 2 CH 2 ; CH 2 CH 2 OCH 2 CH 2 OCH 2 , or CH 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 .