Redox shuttles for lithium ion batteries

1. An electrolyte comprising:

an alkali metal salt;

a polar aprotic solvent; and

a redox shuttle comprising a compound of Formula IVA or IVB; and

wherein:

the electrolyte solution is substantially non-aqueous;

the compound of Formula IVA or IVB is:

R 8 , R 9 , R 10 , and R 11 are each independently H, F, Cl, Br, CN, NO 2 , alkyl, haloalkyl, or alkoxy groups;

at least two of R 8 , R 9 , R 10 , and R 11 are independently tertiary alkyl groups;

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(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 .

4. 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, Br, CN, NO 2 , alkyl, haloalkyl, or alkoxy groups;

X and Y are O; and

Z′ is CH 2 , CH 2 CH 2 , or CHCH.

5. 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.

6. 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.

7. The electrolyte of claim 1 , wherein the redox shuttle has a redox potential of from 3 V to 5 V in the electrolyte.

8. The electrolyte of claim 1 , wherein the redox shuttle is present in the electrolyte from 0.0005 wt % to 50 wt %.

9. The electrolyte of claim 1 , wherein the alkali metal salt is a lithium salt.

10. The electrolyte of claim 1 , 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 SO 3 ]; Li[N(CF 3 SO 2 ) 2 ]; Li[C(CF 3 SO 2 ) 3 ]; LiN(SO 2 C 2 F 5 ) 2 ; or a lithium alkyl fluorophosphate.

11. The electrolyte of claim 1 , wherein the polar aprotic solvent comprises ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dimethyl ether, or γ-butyrolactone.

12. An electrochemical device comprising

a cathode

an anode; and

an electrolyte comprising:

an alkali metal salt;

a polar aprotic solvent; and

a redox shuttle comprising a compound of Formula IVA or IVB;

wherein:

the electrolyte solution is substantially non-aqueous;

the compound of Formula IVA or IVB is:

R 8 , R 9 , R 10 , and R 11 are each independently H, F, Cl, Br, CN, NO 2 , alkyl, haloalkyl, or alkoxy groups;

at least two of R 8 , R 9 , R 10 , and R 11 are independently tertiary alkyl groups;

X and Y are each independently O, S, N, or P; and

Z′ is a linkage between X and Y.

13. The electrochemical device of claim 12 , wherein X and Y are O.

14. The electrochemical device of claim 12 , 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 .

15. The electrochemical device of claim 12 , wherein:

R 8 and R 10 are tert-butyl;

R 9 and R 11 are each independently H, F, Cl, Br, CN, NO 2 , alkyl, haloalkyl, or alkoxy groups;

X and Y are O; and

Z′ is CH 2 , CH 2 CH 2 , or CHCH.

16. The electrochemical device of claim 12 , 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.

17. An electrochemical device comprising

a spinel, olivine, or carbon-coated olivine cathode;

a graphite or amorphous carbon anode; and

a substantially non-aqueous electrolyte comprising:

an alkali metal salt comprising Li[BF 2 (C 2 O 4 )] or Li[B(C 2 O 4 ) 2 ];

a polar aprotic solvent comprising ethyl acetate; propyl acetate; ethylene carbonate; propylene carbonate; dimethyl carbonate; diethyl carbonate; ethyl methyl carbonate; dimethyl ether; or γ-butyrolactone;

a redox shuttle comprising a compound of Formula IVA or IVB; and

an electrode stabilizing additive;

wherein:

the compound of Formula IVA or IVB is:

R 8 , R 9 , R 10 , and R 11 are each independently H, F, Cl, Br, CN, NO 2 , alkyl, haloalkyl, or alkoxy groups;

at least two of R 8 , R 9 , R 10 , and R 11 are independently tertiary alkyl groups;

X and Y are each independently O, S, N, or P; and

Z′ is a linkage between X and Y; and

the electrode stabilizing compound comprises pyridazine; vinyl pyridazine; quinoline; vinyl quinoline; pyridine; vinyl pyridine; indole; vinyl indole; triethanolamine; 1,3-dimethyl butadiene; butadiene; vinyl ethylene carbonate; vinyl carbonate; imidazole; vinyl imidazole; piperidine; vinyl piperidine; pyrimidine; vinyl pyrimidine; pyrazine; vinyl pyrazine; isoquinoline; vinyl isoquinoline; quinoxaline; vinyl quinoxaline; biphenyl; 1,2-diphenyl ether; 1,2-diphenylethane; o-terphenyl; N-methylpyrrole; naphthalene; 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]undecane; 3,9-divinyl-2,4,8-trioxaspiro[5.5]undecane; 3,9-divinyl-2,4-dioxaspiro[5.5]undecane; 3,9-diethylidene-2,4,8,10-tetraoxaspiro[5.5]undecane; 3,9-diethylidene-2,4,8-trioxaspiro[5.5]undecane; 3,9-diethylidene-2,4-dioxaspiro[5.5]undecane; 3,9-dimethylene-2,4,8,10-tetraoxaspiro[5.5]undecane; 3,9-divinyl-1,5,7,11-tetraoxaspiro[5.5]undecane; 3,9-dimethylene-1,5,7,11-tetraoxaspiro[5.5]undecane; or 3,9-diethylidene-1,5,7,11-tetraoxaspiro[5.5]undecane.

18. The electrolyte of claim 17 , wherein the redox shuttle 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.