Power storage device, lithium-ion secondary battery, electric double layer capacitor and lithium-ion capacitor

Abstract

One object is to provide a power storage device including an electrolyte using a room-temperature ionic liquid which includes a univalent anion and a cyclic quaternary ammonium cation having excellent reduction resistance. Another object is to provide a high-performance power storage device. A room-temperature ionic liquid which includes a cyclic quaternary ammonium cation represented by a general formula (G1) below is used for an electrolyte of a power storage device. In the general formula (G1), one or two of R 1 to R 5 are any of an alkyl group having 1 to 20 carbon atoms, a methoxy group, a methoxymethyl group, and a methoxyethyl group. The other three or four of R 1 to R 5 are hydrogen atoms. A − is a univalent imide anion, a univalent methide anion, a perfluoroalkyl sulfonic acid anion, tetrafluoroborate (BF 4 − ), or hexafluorophosphate (PF 6 − ).

1 . (canceled) 
     
     
         2 . A power storage device comprising:
 a first positive electrode;   a first negative electrode;   a first electrolyte salt comprising a lithium ion; and   an ionic liquid represented by a general formula (G2)   
       
         
           
           
               
               
           
         
       
       and
 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; 
 wherein R 2  represents an alkyl group having 1 to 4 carbon atoms, 
 wherein R 1  represents a hydrogen atom, and 
 wherein A −  represents a univalent imide anion selected from (C n F 2n+1 SO 2 ) 2 N −  (n=0 to 4), (C m F 2m+1 SO 3 ) −  (m=0 to 4), and CF 2 (CF 2 SO 2 ) 2 N − . 
 
     
     
         3 . The power storage device according to  claim 2 , wherein the power storage device is a lithium-ion secondary battery. 
     
     
         4 . The power storage device according to  claim 2 , the power storage device further comprising:
 a first solvent,   wherein the first solvent is a room-temperature ionic liquid other than the ionic liquid represented by the general formula (G2).   
     
     
         5 . The power storage device according to  claim 2 , further comprising:
 a second positive electrode; and   a second negative electrode,   wherein the second positive electrode is not electrically connected to the first positive electrode.   
     
     
         6 . The power storage device according to  claim 2 , further comprising a reference electrode, the reference electrode comprising:
 the 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; and   a second electrolyte salt.   
     
     
         7 . The power storage device according to  claim 6 , wherein the second electrolyte salt is different from the first electrolyte salt. 
     
     
         8 . The power storage device according to  claim 7 , wherein the second electrolyte salt comprises a silver ion. 
     
     
         9 . The power storage device according to  claim 2 , wherein the A −  is (FSO 2 ) 2 N −  or (CF 3 SO 2 ) 2 N − . 
     
     
         10 . An electronic appliance comprising the power storage device according to  claim 2 . 
     
     
         11 . A power storage device comprising:
 a first positive electrode;   a first negative electrode;   a first electrolyte salt comprising a lithium ion; and   an ionic liquid represented by a general formula (G2)   
       
         
           
           
               
               
           
         
       
       and
 a reference electrode comprising:
 a second positive electrode; 
 a second negative electrode; 
 a second electrolyte salt; and 
 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 
 
 wherein R 2  represents an alkyl group having 1 to 4 carbon atoms, 
 wherein R 1  represents a hydrogen atom, and 
 wherein A −  represents a univalent imide anion selected from (C n F 2n+1 SO 2 ) 2 N −  (n=0 to 4), (C m F 2m+1 SO 3 ) −  (m=0 to 4), and CF 2 (CF 2 SO 2 ) 2 N − . 
 
     
     
         12 . The power storage device according to  claim 11 , wherein the power storage device is a lithium-ion secondary battery. 
     
     
         13 . The power storage device according to  claim 11 , the power storage device further comprising:
 a first solvent,   wherein the first solvent is a room-temperature ionic liquid other than the ionic liquid represented by the general formula (G2).   
     
     
         14 . The power storage device according to  claim 11 , wherein the second electrolyte salt is different from the first electrolyte salt. 
     
     
         15 . The power storage device according to  claim 11 , wherein the second electrolyte salt comprises a silver ion. 
     
     
         16 . The power storage device according to  claim 11 , wherein the A −  is (FSO 2 ) 2 N −  or (CF 3 SO 2 ) 2 N − . 
     
     
         17 . The power storage device according to  claim 11 ,
 wherein the ionic liquid is represented by a general formula (G4)   
       
         
           
           
               
               
           
         
       
     
     
         18 . An electronic appliance comprising the power storage device according to  claim 11 .