P
USH2097HExpiredUtilityPatentIndex 63

Electrolyte additive to stabilize lithium organic electrolytes for lithium ion cells

Assignee: US ARMYPriority: Feb 4, 1998Filed: Feb 4, 1998Granted: Feb 3, 2004
Est. expiryFeb 4, 2018(expired)· nominal 20-yr term from priority
Inventors:PLICHTA EDWARD J
H01M 10/0568H01M 2300/0037Y02E60/10
63
PatentIndex Score
3
Cited by
4
References
16
Claims

Abstract

A salt additive to lithium conducting organic electrolytes which thermally stabilizes the solution and more particular to provide improved cell operation and storage of lithium ion cells at elevated temperatures is LiBF 4 and is employed in a salt molar ratio of at least about 1:1.

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
       1. An electrolyte electrochemical cells comprising an organic solvent solution having an organic solvent and at least two different lithium salts in which a first one of the lithium salts is LiBF 4  in an amount that is at least an about one to one mole ratio to a second one of the lithium salts present. 
     
     
       2. An electrolyte for electrochemical cells according to  claim 1  wherein the second lithium salt present is selected from the group consisting of LiPF 6 , LiAsF 6 , LiClO 4 , LiAlCl 4 , LiN(CF 3 SO 2 ) 2  and LiC(CF 3 SO 2 ) 3 . 
     
     
       3. An electrolyte for electrochemical cells according to  claim 2  wherein the organic solvent is at least one member selected from the group consisting of propylene carbonate, ethylene carbonate, gamma butyrolactone, methyl formate, dimethyl carbonate and diethyl carbonate. 
     
     
       4. An electrolyte for electrochemical cells according to  claim 1  wherein the organic solvent is at least one member selected from the group consisting of propylene carbonate, ethylene carbonate, gamma butyrolactone, methyl formate, dimethyl carbonate and diethyl carbonate. 
     
     
       5. An electrolyte for electrochemical cells according to  claim 4  wherein the organic solvent is a mixture of ethylene carbonate, propylene carbonate, dimethyl carbonate and methyl formate. 
     
     
       6. An electrolyte for electrochemical cells according to  claim 5  wherein the second lithium salt comprises LiPF 6 . 
     
     
       7. An electrolyte for electrochemical cells according to  claim 4  wherein the organic solvent is a mixture of ethylene carbonate, propylene carbonate, dimethyl carbonate and methyl formate in a volume ratio of 1:1:3:15, respectively. 
     
     
       8. An electrolyte for electrochemical cells according to  claim 7  wherein the second lithium salt comprises LiPF 6 . 
     
     
       9. An electrochemical cell comprising an anode, a cathode and an electrolyte, wherein said electrolyte comprises an organic solvent solution having an organic solvent and at least two different lithium salts in which a first one of the lithium salts is LiBF 4  in an amount that is at least an about one to one mole ratio to a second one of the lithium salts present; 
     
     
       10. An electrochemical cell according to  claim 9  wherein the second lithium salt present is selected from the group consisting of LiPF 6 , LiAsF 6 , LiClO 4 , LiAlCl 4 , LiN(CF 3 SO 2 ) 2  and LiC(CF 3 SO 2 ) 3 . 
     
     
       11. An electrochemical cell according to  claim 10  wherein the organic solvent is at least one member selected from the group consisting of propylene carbonate, ethylene carbonate, gamma butyrolactone, methyl formate, dimethyl carbonate and diethyl carbonate. 
     
     
       12. An electrochemical cell according to  claim 9  wherein the organic solvent is at least one member selected from the group consisting of propylene carbonate, ethylene carbonate, gamma butyrolactone, methyl formate, dimethyl carbonate and diethyl carbonate. 
     
     
       13. An electrochemical cell according to  claim 12  wherein the organic solvent is a mixture of ethylene carbonate, propylene carbonate, dimethyl carbonate and methyl formate. 
     
     
       14. An electrochemical cell according to  claim 13  wherein the second lithium salt comprises LiPF 6 . 
     
     
       15. An electrochemical cell according to  claim 12  wherein the organic solvent is a mixture of ethylene carbonate, propylene carbonate, dimethyl carbonate and methyl formate in a volume ratio of 1:1 :3:15, respectively. 
     
     
       16. An electrochemical cell according to  claim 15  wherein the second lithium salt comprises LiPF 6 .

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