Lithium-ion batteries with intrinsic pulse overcharge protection

1. An electrochemical device comprising:

a cathode comprising at least one primary positive material and at least one secondary positive material;

an anode; and

a non-aqueous electrolyte comprising a redox shuttle additive;

wherein

the redox potential of the redox shuttle additive is greater than the redox potential of the primary positive material;

the redox potential of the redox shuttle additive is lower than the redox potential of the secondary positive material; and

the redox shuttle additive is stable at least up to the redox potential of the secondary positive material.

2. The electrochemical device of claim 1 , wherein the primary positive material is a lithium metal oxide or a mixture of two or more lithium metal oxides, and the secondary positive material is a lithium metal oxide or a mixture of two or more lithium metal oxides.

3. The electrochemical device of claim 1 , wherein the primary positive material is selected from the group consisting of: Li 2 S, spinet, olivine, carbon-coated olivine, LiFePO 4 , LiCoO 2 , LiNiO 2 , LiNi 1−x Co y Met z O 2 , LiMn 0.5 Ni 0.5 O 2 , LiMn 0.3 Co 0.3 Ni 0.3 O 2 , LiMn 2 O 4 , LiFeO 2 , LiMet 0.5 Mn 1.5 O 4 , Li 1+x Mn 2−x O 4 , Li 1+x′ Ni α Mn β Co γ Met′ δ O 2-z′ Y′ z′ , A n′ B′ 2 (XO 4 ) 3 , and mixtures of any two or more thereof, wherein Met is Al, Mg, Ti, B, Ga, Si, Mn, or Co; Met′ is Mg, Zn, Al, Ga, B, Zr, or Ti; A is Li, Ag, Cu, Na, Mn, Fe, Co, Ni, Cu, or Zn; B′ is Ti, V, Cr, Fe, or Zr; X is P, S, Si, W, or Mo; Y′ is F or S; and further wherein 0≦x≦0.3, 0≦y≦0.5, 0≦z≦0.5; 0≦x′≦0.5; 0≦x′≦0.4, 0≦α≦1, 0≦β≦1, 0≦γ≦1, 0≦δ≦0.4, and 0≦z′≦0.4; and 0≦n′≦3.

4. The electrochemical device of claim 1 , wherein the primary positive is selected from the group consisting of: spinel, olivine, carbon-coated olivine, Li 1+x Mn 2−x Met y O 4-m X n , LiFe 1-z Met″ y PO 4-m X n , and mixtures of any two or more thereof, wherein Met is Al, Mg, Ti, B, Ga, Si, Ni, or Co; Met″ is Al, Mg, Ti, B, Ga, Si, Ni, Mn or Co; X is S or F; 0≦x≦0.3, 0≦y≦0.5, 0≦z≦0.5, 0≦m≦0.5, and 0≦n≦0.5.

5. The electrochemical device of claim 1 , wherein the primary positive electrode material may be further stabilized by surface coating the particles of the spinel or olivine with a metal oxide selected from the group consisting of: ZrO 2 , TiO 2 , ZnO 2 , WO 3 , Al 2 O 3 , MgO, SiO 2 , SnO 2 , AlPO 4 , Al(OH) 3 , and mixtures of any two or more thereof.

6. The electrochemical device of claim 1 , wherein the secondary positive material is selected from the group consisting of: spinel, olivine, carbon-coated olivine, LiFePO 4 , LiCoO 2 , LiNiO 2 , LiNi 1−x Co y Met z O 2 , LiMn 0.5 Ni 0.5 O 2 , LiMn 0.3 Co 0.3 Ni 0.3 O 2 , LiMn 2 O 4 , LiFeO 2 , LiMet 0.5 Mn 1.5 O 4 , Li 1+x′ Ni α Mn β Co γ Met′ δ O 2-z′ Y′ z′ , A n′ B′ 2 (XO 4 ) 3 , Li 1+x Mn 2−x O 4 , LiMn 1−x″-y″ Ni x″ Co y″ O 2 , and mixtures of any two or more thereof, wherein Met is Al, Mg, Ti, B, Ga, Si, Mn, or Co; Met′ is Mg, Zn, Al, Ga, B, Zr, or Ti; A is Li, Ag, Cu, Na, Mn, Fe, Co, Ni, Cu, are Zn; B′ is Ti, V, Cr, Fe, or Zr; X is P, S, Si, W, or Mo; Y′ is F or S; and further wherein 0≦x≦0.3, 0≦y≦0.5, 0≦z≦0.5; 0≦x′≦0.4, 0≦α≦1, 0≦β≦1, 0≦γ≦1, 0≦δ≦0.4, and 0≦z′≦0.4; 0≦n′≦3; and 0≦x″≦1, 0≦y″≦1, and 0≦x″+y″≦1.

7. The electrochemical device of claim 1 , wherein the secondary positive material is selected from the group consisting of: spinel, olivine, carbon-coated olivine, Li 1+x Mn 2-z Met y O 4-m X n , LiFe 1-z Met′ y PO 4-m X n , and mixtures of any two or more thereof, wherein Met is Al, Mg, Ti, B, Ga, Si, Ni, or Co; Met″ is Al, Mg, Ti, B, Ga, Si, Ni, Mn or Co; X is S or F; 0≦x≦0.3, 0≦y≦0.5, 0≦z≦0.5, 0≦m≦0.5, and 0≦n≦0.5.

8. The electrochemical device of claim 1 , wherein the secondary positive electrode material may be further stabilized by surface coating the particles of the spinel or olivine with a metal oxide selected from the group consisting of: ZrO 2 , TiO 2 , ZnO 2 , WO 3 , Al 2 O 3 , MgO, SiO 2 , SnO 2 , AlPO 4 , Al(OH) 3 , and mixtures of any two or more thereof.

9. The electrochemical device of claim 1 , wherein the redox shuttle additive is substituted or unsubstituted ferrocene, or a mixture of two or more thereof.

10. The electrochemical device of claim 1 , wherein the redox shuttle additive is a substituted or unsubstituted aromatic compound.

11. The electrochemical device of claim 10 , wherein the substituted aromatic compound is a compound of formula I:

wherein

R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently selected from the group consisting of H, —F, —Cl, —Br, —I, haloalkyl, cycloalkyl, alkyl, aryl, heteroaryl, —CN, —NO 2 , —O-alkyl, —O-aryl, —O-heteroaryl, —S-alkyl, —S-aryl, —S-heteroaryl, and a moiety selected from the group consisting of:

provided that at least one of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 is not H; or any two adjacent groups of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 together form a fused aryl or heteroaryl ring;

each R 7 , R 8 and R 9 is independently a hydrogen, halogen, an alkyl group, an aryl group, a haloalkyl group, or a haloaryl group;

each R 10 , R 11 and R 12 is independently a halogen atom, an alkyl group, an aryl group, a haloalkyl group, or a haloaryl group;

M + is a cation; and

A − is an anion.

12. The electrochemical device of claim 11 , wherein two or more of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently an —O-alkyl, —O-aryl, or —O-heteroaryl group.

13. The electrochemical device of claim 1 , wherein the redox shuttle additive is 2,5-di-(tert-butyl)-1,4-dimethoxybenzene, or a mixture of 2,5-di-(tert-butyl)-1,4-dimethoxybenzene and (tetrafluorobenzo-1,2-dioxyl)-pentafluorophenyl-borane.

14. The electrochemical device of claim 1 , wherein the redox shuttle additive is Li 2 B 10 X 10 or Li 2 B 12 X 12 ; wherein each X is independently selected from the group consisting of H, F, Cl, Br, I, OCH 3 , and OH.

15. The electrochemical device of claim 1 , wherein the redox shuttle additive has a redox potential vs. Li 0 from about 3.0V to about 5.0V.

16. The electrochemical device of claim 15 , wherein the redox shuttle additive is Li 2 B 10 X 10 or Li 2 B 12 X 12 ; wherein each X is independently selected from the group consisting of H, F, Cl, Br, I, OCH 3 , and OH.

17. The electrochemical device of claim 1 , wherein the redox shuttle additive is a mixture of two or more compounds selected from the group consisting of

substituted or unsubstituted ferrocene;

2,5-di-(tert-butyl)-1,4-dimethoxybenzene;

(tetrafluorobenzo-1,2-dioxyl)-pentafluorophenyl-borane;

Li 2 B 10 X 10 or Li 2 B 12 X 12 , wherein each X is independently selected from the group consisting of H, F, Cl, Br, I, OCH 3 , and OH; and

a compound of formula I:

wherein:

R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently selected from the group consisting of H, —F, —Cl, —Br, —I, haloalkyl, cycloalkyl, alkyl, aryl, heteroaryl, —CN, —NO 2 , —O-alkyl, —O-aryl, —O-heteroaryl, —S-alkyl, —S-aryl, —S-heteroaryl, and a moiety selected from the group consisting of:

provided that at least one of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 is not H; or any two adjacent groups of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 together form a fused aryl or heteroaryl ring;

each R 7 , R 8 and R 9 is independently a hydrogen, halogen, an alkyl group, an aryl group, a haloalkyl group, or a haloaryl group;

each R 10 , R 11 and R 12 is independently a halogen atom, an alkyl group, an aryl group, a haloalkyl group, or a haloaryl group;

M + is a cation; and

A − is an anion.

18. The electrochemical device of claim 1 , wherein the electrolyte further comprises a lithium salt.

19. The electrochemical device of claim 18 , wherein the lithium salt is Li[B(C 2 O 4 ) 2 ], Li[BF 2 (C 2 O 4 )], Li[PF 2 (C 2 O 4 ) 2 ], LiClO 4 , LiBF 4 , LiAsF 6 , LiPF 6 , LiCF 3 SO 3 , Li[N(CF 3 SO 2 ) 2 ], Li[C(CF 3 SO 2 ) 3 ], Li[N(SO 2 C 2 F 5 ) 2 ], lithium alkyl fluorophosphates, or a mixture of any two or more thereof.

20. The electrochemical device of claim 18 , wherein the lithium salt is Li 2 B 10 X 10 or Li 2 B 12 X 12 ; wherein each X is independently selected from the group consisting of H, F, Cl, Br, I, OCH 3 , and OH.

21. The electrochemical device of claim 18 , wherein the lithium salt is a mixture of two or more of: Li[B(C 2 O 4 ) 2 ], Li[BF 2 (C 2 O 4 )], Li[PF 2 (C 2 O 4 ) 2 ], LiClO 4 , LiBF 4 , LiAsF 6 , LiPF 6 , LiCF 3 SO 3 , Li[N(CF 3 SO 2 ) 2 ], Li[C(CF 3 SO 2 ) 3 ], Li[N(SO 2 C 2 F 5 ) 2 ], Li 2 B 10 X 10 , and Li 2 B 12 X 12 ; wherein each X is independently selected from the group consisting of H, F, Cl, Br, I, OCH 3 , and OH.

22. The electrochemical device of claim 1 , wherein

the electrochemical device is a lithium secondary battery;

the primary positive material is a lithium metal oxide or a mixture of two or more lithium metal oxides;

the secondary positive material is a lithium metal oxide or a mixture of two or more lithium metal oxides different from the primary positive material;

the anode is graphite, amorphous carbon, Li 4 Ti 5 O 12 , tin alloys, silicon alloys, intermetallic compounds, lithium metal, or mixtures of any two or more thereof; and

the anode and cathode are separated from each other by a porous separator.

23. The electrochemical device of claim 22 , wherein the redox shuttle additive is a mixture of two or more compounds selected from the group consisting of:

substituted or unsubstituted ferrocene;

2,5-di-(tert-butyl)-1,4-dimethoxybenzene;

(tetrafluorobenzo-1,2-dioxyl)-pentafluorophenyl-borane;

Li 2 B 10 X 10 or Li 2 B 12 X 12 , wherein each X is independently selected from the group consisting of H, F, Cl, Br, I, OCH 3 , and OH; and

a compound of formula I:

wherein:

R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently selected from the group consisting of H, —F, —Cl, —Br, —I, haloalkyl, cycloalkyl, alkyl, aryl, heteroaryl, —CN, —NO 2 , —O-alkyl, —O-aryl, —O-heteroaryl, —S-alkyl, —S-aryl, —S-heteroaryl, and a moiety selected from the group consisting of:

provided that at least one of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 is not H; or any two adjacent groups of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 together form a fused aryl or heteroaryl ring;

each R 7 , R 8 and R 9 is independently a hydrogen, halogen, an alkyl group, an aryl group, a haloalkyl group, or a haloaryl group;

each R 10 , R 11 and R 12 is independently a halogen atom, an alkyl group, an aryl group, a haloalkyl group, or a haloaryl group;

M + is a cation; and

A − is an anion.

24. A electrochemical device comprising:

a cathode comprising at least one primary positive material and at least one secondary positive material;

an anode; and

a non-aqueous electrolyte comprising;

Li 2 B 10 X 10 , Li 2 B 12 X 12 , or a mixture thereof; wherein each X is independently selected from the group consisting of H, F, Cl, Br, I, OCH 3 , and OH;

a polar aprotic solvent; and

a redox shuttle additive;

wherein,

the primary positive material is LiFePO 4 ;

the secondary positive material is spinel, LiMn 2 O 4 , LiCoO 2 , LiCo 1−α′ Al α′ O 2 , or Li 1+x′ Ni α Mn β Co γ Met′ δ O 2-z′ Y′ z′ , wherein Met′ is Mg, Zn, Al, Ga, B, Zr, or Ti; A is Li, Ag, Cu, Na, Mn, Fe, Co, Ni, Cu, and Zn; Y′ is F or S; 0≦α′≦0.2, 0≦x′≦0.4, 0≦α≦1, 0≦β≦1, 0≦γ≦1, 0≦δ≦0.4, and 0≦z′≦0.4; and

the redox shuttle is 2,5-di-(tert-butyl)-1,4-dimethoxybenzene.