Electrolyte for a lithium battery and a lithium battery comprising the same

Abstract

The present invention relates to an electrolyte for a lithium battery and a lithium battery comprising the same. The electrolyte includes a non-aqueous organic solvent, a lithium salt, and a first additive capable of forming a chelating complex with a transition metal and which is stable at voltages ranging from about 2.5 to about 4.8 V.

1 . An electrolyte for a lithium battery comprising: 
 a non-aqueous organic solvent;    a lithium salt; and    a first additive capable of forming a chelating complex with a transition metal, the first additive being stable at voltages ranging from about 2.5 to about 4.8 V.    
     
     
         2 . The electrolyte of  claim 1 , wherein the first additive comprises a compound selected from the group consisting of compounds represented by Formulas 1 to 3 and mixtures thereof:  
       
         
           
           
               
               
           
         
         wherein n is an integer ranging from 0 to 10,  
         n1 is an integer ranging from 0 to 15, wherein when n1 is an odd number, a is 1 and when n1 is an even number, a is either ½ or 1; and  
         at least one of R 1  through R 3  and at least one of R 4  through R 6  is a compound represented by A x R′, wherein A is selected from the group consisting of N, O, P, or S, x is 0 or 1, and R′ is selected from the group consisting of CN, C 1  to C 15  linear alkyls, C 1 to C   15  linear carboxyls, C 1  to C 15  branch alkyls and C 1  to C 15  branch carboxyls, and wherein the remaining R1 through R6 groups each comprises a material selected from the group consisting of H, halogens, C 1  to C 15  alkyls and C 6  to C 15  aryls.  
       
     
     
         3 . The electrolyte of  claim 2 , wherein the first additive comprises a compound selected from the group consisting of compounds represented by Formulas 4 to 26:  
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
     
     
         4 . The electrolyte of  claim 1 , wherein the first additive is present in the electrolyte in an amount ranging from about 0.1 wt % to about 10 wt % based on the total weight of electrolyte.  
     
     
         5 . The electrolyte of  claim 4 , wherein the first additive is present in the electrolyte in an amount ranging from about 1 wt % to about 5 wt % based on the total weight of electrolyte.  
     
     
         6 . The electrolyte of  claim 4 , wherein the first additive is present in the electrolyte in an amount ranging from about 3 wt % to about 5 wt % based on the total weight of electrolyte.  
     
     
         7 . The electrolyte of  claim 1 , further comprising a second additive capable of releasing a transition metal from a positive electrode.  
     
     
         8 . The electrolyte of  claim 7 , wherein the second additive is an ester-based compound.  
     
     
         9 . The electrolyte of  claim 8 , wherein the second additive is selected from the group consisting of phenyl acetate, benzyl benzoate, ethyl acetate, 1-naphthyl acetate, 2-chromanone and ethyl propionate.  
     
     
         10 . The electrolyte of  claim 7 , wherein the second additive is present in the electrolyte in an amount ranging from about 1 to about 10 parts by weight based on 100 parts by weight of the electrolyte.  
     
     
         11 . The electrolyte of  claim 10 , wherein the second additive is present in the electrolyte in an amount ranging from about 1 to about 7 parts by weight based on 100 parts by weight of the electrolyte.  
     
     
         12 . The electrolyte of  claim 11 , wherein the second additive is present in the electrolyte in an amount ranging from about 3 to about 5 parts by weight based on 100 parts by weight of the electrolyte.  
     
     
         13 . The electrolyte  claim 1 , wherein the lithium salt is selected from the group consisting of LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiClO 4 , LiCF 3 SO 3 , Li(CF 3 SO 2 ) 2 N, LiC 4 F 9 SO 3 , LiAlO 4 , LiAlCl 4 , LiCl, Lil, LiN(C x F 2x+1 SO 2 )(C y F 2y+1 SO 2 ) wherein x and y are natural numbers and mixtures thereof.  
     
     
         14 . The electrolyte of  claim 1 , wherein the lithium salt has a concentration ranging from about 0.6 M to about 2.0 M.  
     
     
         15 . The electrolyte of  claim 1 , wherein the lithium salt has a concentration ranging from about 0.7 M to about 1.6 M.  
     
     
         16 . The electrolyte of  claim 1 , wherein the non-aqueous organic solvent is selected from the group consisting of carbonates, esters, ethers, ketones and mixtures thereof.  
     
     
         17 . The electrolyte of  claim 16 , wherein the carbonates are selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methylethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC) and mixtures thereof.  
     
     
         18 . The electrolyte of  claim 16 , wherein the esters are selected from the group consisting of n-methyl acetate, n-ethyl acetate, n-propyl acetate and mixtures thereof.  
     
     
         19 . The electrolyte of  claim 16 , wherein the non-aqueous organic solvent comprises a carbonate comprising a mixture of chain carbonates and cyclic carbonates, the volume ratio of the chain carbonates to the cyclic carbonates ranging from about 1:1 to about 1:9.  
     
     
         20 . The electrolyte of  claim 1 , wherein the non-aqueous solvent comprises a mixture of a carbonate solvent and an aromatic hydrocarbon solvent.  
     
     
         21 . The electrolyte of  claim 20 , wherein the volume ratio of the carbonate solvent to the aromatic hydrocarbon solvent ranges from about 1:1 to about 30:1.  
     
     
         22 . The electrolyte of  claim 20 , wherein the aromatic hydrocarbon solvent is selected from the group consisting of solvents represented by Formula 27:  
       
         
           
           
               
               
           
         
         wherein q is an integer ranging from 0 to 6 and R10 is selected from the group consisting of halogens and C 1  to C 10  alkyls.  
       
     
     
         23 . The electrolyte of  claim 22 , wherein the aromatic hydrocarbon solvent is selected from the group consisting of benzene, fluorobenzene, toluene, trifluorotoluene, chlorobenzene, xylene and mixtures thereof.  
     
     
         24 . The electrolyte of  claim 1 , further comprising a third additive selected from the group consisting of carbonates having halogen substituents, carbonates having cyano (CN) substituents, carbonates having nitro (NO 2 ) substituents, vinylene carbonate, divinylsulfone, ethylene sulfite and mixtures thereof.  
     
     
         25 . The electrolyte of  claim 24 , wherein the third additive is selected from the group consisting of carbonates having halogen substituents, carbonates having cyano (CN) substituents and carbonates having nitro (NO 2 ) substituents.  
     
     
         26 . The electrolyte of  claim 24 , wherein the third additive is selected from the group consisting of compounds represented by Formula 28:  
       
         
           
           
               
               
           
         
         wherein X1 is selected from the group consisting of halogens, cyano (CN) groups, and nitro (NO 2 ) groups.  
       
     
     
         27 . The electrolyte of  claim 24 , wherein the third additive is fluoroethylene carbonate.  
     
     
         28 . An electrolyte for a lithium battery comprising: 
 a non-aqueous organic solvent;    a lithium salt;    a first additive capable of forming a chelating complex with a transition metal, the first additive being stable at a voltage ranging from about 2.5 to about 4.8 V;    a second additive capable of releasing a transition metal from a positive electrode.    
     
     
         29 . The electrolyte of  claim 28 , further comprising a third additive selected from the group consisting of carbonates having halogen substituents, carbonates having cyano (CN) substituents, carbonates having nitro (NO 2 ) substituents, vinylene carbonate, divinylsulfone, ethylene sulfite and mixtures thereof.  
     
     
         30 . A lithium battery comprising: 
 an electrolyte comprising: 
 a non-aqueous organic solvent,  
 a lithium salt, and  
 a first additive capable of forming a chelating complex with a transition metal, the first additive being stable at voltages ranging from about 2.5 to about 4.8 V;  
   a positive electrode comprising a positive active material capable of intercalating and deintercalating lithium ions; and    a negative electrode comprising an active material selected from the group consisting of materials capable of intercalating/deintercalating lithium ions, lithium metals, lithium-containing alloys, and materials capable of forming lithium-containing compounds by reversibly reacting lithium.    
     
     
         31 . The lithium battery of  claim 30 , wherein the first additive comprises a compound selected from the group consisting of compounds represented by Formulas (1) to (3) and mixtures thereof:  
       
         
           
           
               
               
           
         
         wherein n is an integer ranging from 0 to 10,  
         n1 is an integer ranging from 0 to 15, wherein when n1 is an odd number, a is 1 and when n1 is an even number, a is either ½ or 1; and  
         at least one of R 1  through R 3  and at least one of R 4  through R 6  is a compound represented by A x R′, wherein A is selected from the group consisting of N, O, P, or S, x is 0 or 1, and R′ is selected from the group consisting of CN, C 1  to C 15  linear alkyls, C 1  to C 15  linear carboxyls, C 1  to C 15  branch alkyls and C 1  to C 15  branch carboxyls, and wherein the remaining R1 through R6 groups each comprises a material selected from the group consisting of H, halogens, C 1  to C 15  alkyls and C 6  to C 15  aryls.  
       
     
     
         32 . The lithium battery of  claim 31 , wherein the first additive comprises a compound selected from the group consisting of compounds represented by Formulas 4 to 26 and mixtures thereof:  
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
     
     
         33 . The lithium battery of  claim 30 , wherein the first additive is present in the electrolyte in an amount ranging from about 0.1 wt % to about 10 wt % based on the total weight of electrolyte.  
     
     
         34 . The lithium battery of  claim 33 , wherein the first additive is present in the electrolyte in an amount ranging from about 1 wt % to about 5 wt % based on the total weight of electrolyte.  
     
     
         35 . The lithium battery of  claim 34 , wherein the first additive is present in the electrolyte in an amount ranging from about 3 wt % to about 5 wt % based on the total weight of electrolyte.  
     
     
         36 . The lithium battery of  claim 30 , wherein the electrolyte further comprises a second additive capable of releasing a transition metal from the positive electrode.  
     
     
         37 . The lithium battery of  claim 36 , wherein the second additive is an ester-based compound.  
     
     
         38 . The lithium battery of  claim 37 , wherein the second additive is selected from the group consisting of phenyl acetate, benzyl benzoate, ethyl acetate, 1-naphthyl acetate, 2-chromanone, and ethyl propionate.  
     
     
         39 . The lithium battery of  claim 36 , wherein the second additive is present in the electrolyte in an amount ranging from about 1 to about 10 parts by weight based on 100 parts by weight of the electrolyte.  
     
     
         40 . The lithium battery of  claim 39 , wherein the second additive is present in the electrolyte in an amount ranging from about 1 to about 7 parts by weight based on 100 parts by weight of the electrolyte.  
     
     
         41 . The lithium battery of  claim 40 , wherein the second additive is present in the electrolyte in an amount ranging from about 3 to about 5 parts by weight based on 100 parts by weight of the electrolyte.  
     
     
         42 . The lithium battery of  claim 30 , wherein the non-aqueous organic solvent is selected from the group consisting of carbonate, esters, ethers, ketones and mixtures thereof.  
     
     
         43 . The lithium battery of  claim 42 , wherein the carbonates are selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methylethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC) and mixtures thereof.  
     
     
         44 . The lithium battery of  claim 30 , wherein the non-aqueous solvent comprises a mixture of a carbonate solvent and an aromatic hydrocarbon solvent.  
     
     
         45 . The lithium battery of  claim 44 , wherein the aromatic hydrocarbon solvent comprises a solvent represented by Formula 27:  
       
         
           
           
               
               
           
         
         wherein q is an integer ranging from 0 to 6 and R10 is selected from the group consisting of halogens and C 1  to C 10  alkyls.  
       
     
     
         46 . The lithium battery of  claim 45 , wherein the aromatic hydrocarbon solvent is selected from the group consisting of benzene, fluorobenzene, toluene, trifluorotoluene, chlorobenzene, xylene and mixtures thereof.  
     
     
         47 . The lithium battery of  claim 30 , wherein the electrolyte further comprises a third additive selected from the group consisting of carbonates having halogen substituents, carbonates having cyano (CN) substituents, carbonates having nitro (NO 2 ) substituents, vinylene carbonate, divinylsulfone, ethylene sulfite and mixtures thereof.  
     
     
         48 . The lithium battery of  claim 47 , wherein the third additive is selected from the group consisting of carbonates having halogen substituents, carbonates having cyano (CN) substituents and carbonates having nitro (NO 2 ) substituents.  
     
     
         49 . The lithium battery of  claim 48 , wherein the third additive is selected from the group consisting of compounds represented by Formula 28:  
       
         
           
           
               
               
           
         
         wherein X1 is selected from the group consisting of halogens, cyano (CN) groups, and nitro (NO 2 ) groups.  
       
     
     
         50 . The lithium battery of  claim 48 , wherein the negative active material comprises a carbonaceous material capable of intercalating/deintercalating lithium ions.  
     
     
         51 . A lithium battery comprising: 
 a positive electrode comprising a positive active material capable of intercalating and deintercalating lithium ions;    a negative electrode comprising an active material selected from the group consisting of materials capable of intercalating/deintercalating lithium ions, lithium metals, lithium-containing alloys, and materials capable of forming lithium-containing compounds by reversibly reacting lithium; and    an electrolyte comprising: 
 a non-aqueous organic solvent,  
 a lithium salt,  
 a first additive capable of forming a chelating complex with a transition metal, the first additive being stable at voltages ranging from about 2.5 to about 4.8 V, and  
 a second additive capable of releasing a transition metal from the positive electrode.  
   
     
     
         52 . The lithium battery of  claim 51 , wherein the electrolyte further comprises a third additive selected from the group consisting of carbonates having halogen substituents, carbonates having cyano (CN) substituents, carbonates having nitro (NO 2 ) substituents, vinylene carbonate, divinylsulfone, ethylene sulfite and mixtures thereof.