Nonaqueous electrolytic solutions and nonaqueous-electrolyte batteries

Abstract

Nonaqueous electrolytes capable of providing a battery having a high capacity and excellent in storability and cycle characteristics are provided. Also provided are nonaqueous-electrolyte batteries produced with the electrolytes. The nonaqueous electrolytes include ones which (1) contains a cyclic carbonate having an unsaturated bond and further contains a fluorinated cyclic carbonate having two or more fluorine atoms, (2) contains an aromatic compound having 7-18 carbon atoms in total and further contains a fluorinated cyclic carbonate having two or more fluorine atoms, (3) contains diethyl carbonate and further contains a fluorinated cyclic carbonate having two or more fluorine atoms, or (4) contains at least one compound selected from the group consisting of cyclic sulfonic acid ester compounds, di-sulfonic acid ester compounds, nitrile compounds, and compounds represented by general formula (1) and further contains a fluorinated cyclic carbonate having two or more fluorine atoms. The electrolytes further include (5) a nonaqueous electrolyte characterized by being an electrolytic solution for use in a high-voltage battery having a final charge voltage of 4.3 V or higher and containing a fluorinated cyclic carbonate having two or more fluorine atoms.

1 . A nonaqueous electrolyte comprising an electrolyte and a nonaqueous solvent for dissolving the electrolyte, wherein the nonaqueous electrolyte comprises a cyclic carbonate having an unsaturated bond and a fluorinated cyclic carbonate having two or more fluorine atoms. 
   
   
       2 . A nonaqueous electrolyte comprising an electrolyte and a nonaqueous solvent for dissolving the electrolyte, wherein the nonaqueous electrolyte comprises an aromatic compound having 7-18 carbon atoms in total and a fluorinated cyclic carbonate having two or more fluorine atoms. 
   
   
       3 . A nonaqueous electrolyte comprising an electrolyte and a nonaqueous solvent for dissolving the electrolyte, wherein the nonaqueous solvent comprises diethyl carbonate and a fluorinated cyclic carbonate having two or more fluorine atoms. 
   
   
       4 . A nonaqueous electrolyte comprising an electrolyte and a nonaqueous solvent for dissolving the electrolyte, wherein the nonaqueous electrolyte comprises: at least one compound selected from the group consisting of cyclic sulfonic acid ester compounds, di-sulfonic acid ester compounds, nitrile compounds, and compounds represented by formula (1); and a fluorinated cyclic carbonate having two or more fluorine atoms: 
     
       
         
         
             
             
         
       
     
     wherein R 1  to R 3  each independently represent an alkyl group which has 1-12 carbon atoms and may be substituted with a fluorine atom; and n represents an integer of 0-6. 
   
   
       5 . The nonaqueous electrolyte according to  claim 1 , wherein the cyclic carbonate having an unsaturated bond is at least one compound selected from the group consisting of vinylene carbonate compounds, vinylethylene carbonate compounds, and methylene-ethylene carbonate compounds. 
   
   
       6 . The nonaqueous electrolyte according to  claim 1 , wherein the cyclic carbonate having an unsaturated bond is at least one of vinylene carbonate and vinylethylene carbonate. 
   
   
       7 . The nonaqueous electrolyte according to  claim 1 , wherein the proportion of the cyclic carbonate having an unsaturated bond in the nonaqueous electrolyte is from 0.001% by weight to 8% by weight. 
   
   
       8 . The nonaqueous electrolyte according to  claim 2 , wherein the aromatic compound has 10-18 carbon atoms in total. 
   
   
       9 . The nonaqueous electrolyte according to  claim 2 , wherein the aromatic compound having 7-18 carbon atoms in total is at least one compound selected from the group consisting of biphenyl, alkylbiphenyl, terphenyl, partly hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, and dibenzofuran. 
   
   
       10 . The nonaqueous electrolyte according to  claim 2 , wherein the proportion of the aromatic compound having 7-18 carbon atoms in total in the nonaqueous electrolyte is from 0.001% by weight to 5% by weight. 
   
   
       11 . The nonaqueous electrolyte according to  claim 3 , wherein the proportion of the diethyl carbonate in the whole nonaqueous solvent is from 10% by volume to 90% by volume. 
   
   
       12 . The nonaqueous electrolyte according to  claim 4 , wherein the cyclic sulfonic acid ester compounds are at least one compound selected from the group consisting of 1,3-propanesultone, 1,4-butanesultone, 1,3-propenesultone, and 1,4-butenesultone. 
   
   
       13 . The nonaqueous electrolyte according to  claim 4 , wherein the di-sulfonic acid ester compounds are at least one compound selected from the group consisting of ethanediol disulfonate, 1,2-propanediol disulfonate, 1,3-propanediol disulfonate, 1,2-butanediol disulfonate, 1,3-butanediol disulfonate and 1,4-butanediol disulfonate. 
   
   
       14 . The nonaqueous electrolyte according to  claim 4 , wherein the nitrile compounds are at least one compound selected from the group consisting of acetonitrile, propinonitrile, butyronitrile, valeronitrile, crotononitrile, 3-methylcrotononitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, and fumaronitrile. 
   
   
       15 . The nonaqueous electrolyte according to  claim 4 , wherein R 1  to R 3  in formula (1) have 2-8 carbon atoms. 
   
   
       16 . The nonaqueous electrolyte according to  claim 4 , wherein n in formula (1) is 0, 1, or 2. 
   
   
       17 . The nonaqueous electrolyte according to  claim 4 , wherein the total content of the at least one compound selected from the group consisting of cyclic sulfonic acid ester compounds, di-sulfonic acid ester compounds, nitrile compounds, and compounds represented by formula (1) in the nonaqueous electrolyte is from 0.001% by weight to 5% by weight. 
   
   
       18 . The nonaqueous electrolyte according to  claim 1 , wherein the fluorinated cyclic carbonate having two or more fluorine atoms is a fluorinated ethylene carbonate having two or more fluorine atoms. 
   
   
       19 . The nonaqueous electrolyte according to  claim 1 , wherein the fluorinated cyclic carbonate having two or more fluorine atoms is at least one compound selected from the group consisting of cis-4,5-difluoro-1,3-dioxolan-2-one, trans-4,5-difluoro-1,3-dioxolan-2-one, and 4,4-difluoro-1,3-dioxolan-2-one. 
   
   
       20 . The nonaqueous electrolyte according to  claim 1 , wherein the proportion of the fluorinated cyclic carbonate having two or more fluorine atoms in the nonaqueous electrolyte is 0.001-10% by weight. 
   
   
       21 . The nonaqueous electrolyte according to  claim 1 , wherein the proportion of the fluorinated cyclic carbonate having two or more fluorine atoms in the nonaqueous electrolyte is 0.01-4% by weight. 
   
   
       22 . A nonaqueous electrolyte comprising an electrolyte and a nonaqueous solvent for dissolving the electrolyte, wherein the nonaqueous electrolyte is an electrolyte for use in a high-voltage battery having a final charge voltage of 4.3 V or higher, and comprises a fluorinated cyclic carbonate having two or more fluorine atoms. 
   
   
       23 . The nonaqueous electrolyte according to  claim 22 , which comprises a cyclic carbonate having an unsaturated bond. 
   
   
       24 . The nonaqueous electrolyte according to  claim 22 , which comprises an aromatic compound having 7-18 carbon atoms in total. 
   
   
       25 . The nonaqueous electrolyte according to  claim 22 , which comprises diethyl carbonate. 
   
   
       26 . The nonaqueous electrolyte according to  claim 22 , which comprises at least one compound selected from the group consisting of cyclic sulfonic acid ester compounds, di-sulfonic acid ester compounds, nitrile compounds, and compounds represented by formula (1): 
     
       
         
         
             
             
         
       
     
     wherein R 1  to R 3  each independently represent an alkyl group which has 1-12 carbon atoms and may be substituted with a fluorine atom; and n represents an integer of 0-6. 
   
   
       27 . A nonaqueous-electrolyte battery comprising: a negative electrode and a positive electrode which are capable of occluding/releasing lithium ions; and a nonaqueous electrolyte, wherein the nonaqueous electrolyte is the nonaqueous electrolyte according to  claim 1 . 
   
   
       28 . The nonaqueous-electrolyte secondary battery according to  claim 27 , wherein the negative electrode comprises at least one of carbonaceous materials and metal compounds capable of occluding and releasing lithium. 
   
   
       29 . The nonaqueous-electrolyte secondary battery according to  claim 27 , wherein the positive electrode comprises a lithium-transition metal composite oxide material. 
   
   
       30 . The nonaqueous electrolyte according to  claim 5 , wherein the cyclic carbonate having an unsaturated bond is at least one of vinylene carbonate and vinylethylene carbonate. 
   
   
       31 . The nonaqueous electrolyte according to  claim 8 , wherein the aromatic compound having 7-18 carbon atoms in total is at least one compound selected from the group consisting of biphenyl, alkylbiphenyl, terphenyl, partly hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, and dibenzofuran. 
   
   
       32 . The nonaqueous electrolyte according to  claim 15 , wherein n in formula (1) is 0, 1, or 2.