Heteroaromatic-based electrolytes for lithium and lithium-ion batteries

Abstract

The present invention provides an electrolyte for lithium and/or lithium-ion batteries comprising a lithium salt in a liquid carrier comprising heteroaromatic compound including a five-membered or six-membered heteroaromatic ring moiety comprising carbon atoms and at least one heteroatom forming a neutral aromatic ring, the at least one heteroatom being selected from a Group V element (preferably N) and a Group VI element (preferably O or S), the heteroaromatic ring moiety bearing least one carboxylic ester or carboxylic anhydride substituent bound to at least one carbon atom of the heteroaromatic ring. Preferred heteroaromatic ring moieties include pyridine compounds, pyrazine compounds, pyrrole compounds, furan compounds, and thiophene compounds.

1 . An electrolyte composition suitable for use in a lithium battery, a lithium-ion battery, or both; the electrolyte composition comprising a lithium salt in a liquid carrier comprising a heteroaromatic compound including a five-membered or six-membered heteroaromatic ring moiety comprising carbon atoms and at least one heteroatom forming a neutral aromatic ring, the at least one heteroatom being selected from a Group V element and a Group VI element, the heteroaromatic ring moiety bearing least one carboxylic ester or carboxylic anhydride substituent bound to at least one carbon atom of the heteroaromatic ring. 
     
     
         2 . The electrolyte composition of  claim 1  wherein the lithium salt comprises LiPF 6 , LiBF 4 , LiF 2 BC 2 O 4 , LiB(C 2 O 4 ) 2 , LiClO 4 , LiAsF 6 , LiN(SO 2 CF 3 ) 2 , LiC(SO 2 CF 3 ) 3 , LiSO 3 CF 3 , LiPF 3 (CF 2 CF 3 ) 3 , or any combination of two or more thereof. 
     
     
         3 . The electrolyte composition of  claim 1  wherein the lithium salt is present at a concentration in the range of about 0.1 to about 5 M. 
     
     
         4 . The electrolyte composition of  claim 1  wherein the lithium salt is present at a concentration in the range of about 1 to about 1.5 M. 
     
     
         5 . The electrolyte composition of  claim 1  wherein the liquid carrier also comprises at least one additional organic solvent. 
     
     
         6 . The electrolyte composition of  claim 1  wherein the liquid carrier also comprises at least one organic carbonate solvent selected from the group consisting of ethylene carbonate, propylene carbonate, dimethylcarbonate, and ethylmethylcarbonate. 
     
     
         7 . The electrolyte composition of  claim 1  wherein the heteroaromatic compound is a material represented by the general Formula (I): 
       
         
           
           
               
               
           
         
         wherein: 
         each of the X atoms, X 1 , X 2 , X 3 , X 4 , X 5 , and X 6 , independently is C or a heteroatom selected from a Group V element and a Group VI element, at least two of the X atoms are C atoms, and at least one of the X atoms is a heteroatom, with the provisos that: (a) the R substituent, R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 , on a C atom independently is selected from the group consisting of H, alkyl, alkenyl, alkynyl, aryl, arylalkyl, fluoroalkyl, fluoroalkenyl, fluoroalkynyl, fluoroaryl, fluoroarylalkyl, a carboxylic anhydride, and a carboxylic ester selected from the group consisting of an alkyl ester, an alkenyl ester, an alkynyl ester, an aryl ester, an arylalkyl ester, a fluoroalkyl ester, a fluoroalkenyl ester, a fluoroalkynyl ester, a fluoroaryl ester, and a fluoroarylalkyl ester; (b) any R substituent on a heteroatom independently is absent or is selected from the group consisting H, alkyl, alkenyl, alkynyl, aryl, arylalkyl, fluoroalkyl, fluoroalkenyl, fluoroalkynyl, fluoroaryl, and fluoroarylalkyl; (c) the combination of X atoms and R substituents forms a neutral aromatic ring; and (d) optionally, R substituents on two adjacent C atoms together form a cyclic carboxylic anhydride group; 
         at least one R substituent on a C atom is selected from a carboxylic ester and a carboxylic anhydride; and 
         n is 0 or 1; with the provisos that (i) when n is 1, then the heteroatom is a Group V element, and (ii) when n is 0, then X 1  and X 5  are joined by a covalent bond. 
       
     
     
         8 . The electrolyte composition of  claim 7  wherein the at least one heteroatom is selected from the group consisting of N, O, and S. 
     
     
         9 . The electrolyte of  claim 7  wherein one or two R substituents on a C atom of the compound of Formula (I) is selected from a carboxylic ester and a carboxylic anhydride, or two adjacent R substituents on C atoms together form a cyclic anhydride; the remainder of the R substituents on carbon atoms are H, and each R substituent on a heteroatom is either absent, or selected from H and C 1  to C 4  alkyl. 
     
     
         10 . The electrolyte of  claim 9  wherein the carboxylic ester is a C 1  to C 4  alkyl carboxylic ester. 
     
     
         11 . The electrolyte of  claim 1  wherein the heteroaromatic compound comprises a pyridine moiety, and is represented by general Formula (II): 
       
         
           
           
               
               
           
         
         wherein: 
         m is 1, 2, 3, 4, or 5; each R 7  is attached to a carbon atom of the pyridine moiety and independently is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, arylalkyl, fluoroalkyl, fluoroalkenyl, fluoroalkynyl, fluoroaryl, fluoroarylalkyl, a carboxylic anhydride, and a carboxylic ester selected from the group consisting of an alkyl ester, an alkenyl ester, an alkynyl ester, an aryl ester, an arylalkyl ester, a fluoroalkyl ester, a fluoroalkenyl ester, a fluoroalkynyl ester, a fluoroaryl ester, and a fluoroarylalkyl ester; 
         optionally R 7  substituents on two adjacent C atoms together form a cyclic carboxylic anhydride group; and 
         the compound bears at least one R 7  substituent selected from a carboxylic anhydride and a carboxylic ester. 
       
     
     
         12 . The electrolyte of  claim 11  wherein m is 1 or 2 and each R 7  substituent is selected from a carboxylic ester and a carboxylic anhydride, or two adjacent R 7  substituents together form a cyclic anhydride. 
     
     
         13 . The electrolyte of  claim 12  wherein the carboxylic ester is a C 1  to C 4  alkyl carboxylic ester. 
     
     
         14 . The electrolyte of  claim 1  wherein the heteroaromatic compound comprises a pyrazine moiety, and is represented by general Formula (III): 
       
         
           
           
               
               
           
         
         wherein p is 1, 2, 3, or 4; each R 8  is attached to a carbon atom of the pyrazine moiety and independently is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, arylalkyl, fluoroalkyl, fluoroalkenyl, fluoroalkynyl, fluoroaryl, fluoroarylalkyl, a carboxylic anhydride, and a carboxylic ester selected from the group consisting of an alkyl ester, an alkenyl ester, an alkynyl ester, an aryl ester, an arylalkyl ester, a fluoroalkyl ester, a fluoroalkenyl ester, a fluoroalkynyl ester, a fluoroaryl ester, and a fluoroarylalkyl ester; 
         optionally R 8  substituents on two adjacent C atoms together form a cyclic carboxylic anhydride group; and 
         the compound bears at least one R 8  substituent selected from a carboxylic anhydride and a carboxylic ester. 
       
     
     
         15 . The electrolyte of  claim 14  wherein p is 1 or 2 and each R 8  substituent is selected from a carboxylic ester and a carboxylic anhydride, or two adjacent R 8  substituents together form a cyclic anhydride. 
     
     
         16 . The electrolyte of  claim 15  wherein the carboxylic ester is a C 1  to C 4  alkyl carboxylic ester. 
     
     
         17 . The electrolyte of  claim 1  wherein the heteroaromatic compound comprises a pyrrole moiety, and is represented by general Formula (IV): 
       
         
           
           
               
               
           
         
         wherein x is 1, 2, 3, or 4; each R 9  is attached to a carbon atom of the pyrrole moiety and independently is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, arylalkyl, fluoroalkyl, fluoroalkenyl, fluoroalkynyl, fluoroaryl, fluoroarylalkyl, a carboxylic anhydride, and a carboxylic ester selected from the group consisting of an alkyl ester, an alkenyl ester, an alkynyl ester, an aryl ester, an arylalkyl ester, a fluoroalkyl ester, a fluoroalkenyl ester, a fluoroalkynyl ester, a fluoroaryl ester, and a fluoroarylalkyl ester; 
         optionally R 9  substituents on two adjacent C atoms together form a cyclic carboxylic anhydride group; 
         R 10  is selected from the group consisting of H, alkyl, alkenyl, alkynyl, aryl, arylalkyl, fluoroalkyl, fluoroalkenyl, fluoroalkynyl, fluoroaryl, and fluoroarylalkyl; 
         and the compound bears at least one R 9  substituent selected from a carboxylic anhydride and a carboxylic ester. 
       
     
     
         18 . The electrolyte of  claim 17  wherein x is 1 or 2 and each R 9  substituent is selected from a carboxylic ester and a carboxylic anhydride, or two adjacent R 9  substituents together form a cyclic anhydride; and R 10  is selected from H and C 1  to C 4  alkyl. 
     
     
         19 . The electrolyte of  claim 18  wherein the carboxylic ester is a C 1  to C 4  alkyl carboxylic ester. 
     
     
         20 . The electrolyte of  claim 1  wherein the heteroaromatic compound comprises a furan moiety, and is represented by general Formula (V): 
       
         
           
           
               
               
           
         
         wherein y is 1, 2, 3, or 4; each R 11  is attached to a carbon atom of the furan moiety and independently is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, arylalkyl, fluoroalkyl, fluoroalkenyl, fluoroalkynyl, fluoroaryl, fluoroarylalkyl, a carboxylic anhydride, and a carboxylic ester selected from the group consisting of an alkyl ester, an alkenyl ester, an alkynyl ester, an aryl ester, an arylalkyl ester, a fluoroalkyl ester, a fluoroalkenyl ester, a fluoroalkynyl ester, a fluoroaryl ester, and a fluoroarylalkyl ester; 
         optionally R 11  substituents on two adjacent C atoms together form a cyclic carboxylic anhydride group; and 
         the compound bears at least one R 11  substituent selected from a carboxylic anhydride and a carboxylic ester. 
       
     
     
         21 . The electrolyte of  claim 20  wherein y is 1 or 2 and each R 11  substituent is selected from a carboxylic ester and a carboxylic anhydride, or two adjacent R 11  substituents together form a cyclic anhydride. 
     
     
         22 . The electrolyte of  claim 21  wherein the carboxylic ester is a C 1  to C 4  alkyl carboxylic ester. 
     
     
         23 . The electrolyte of  claim 1  wherein the heteroaromatic compound comprises a thiophene moiety, and is represented by general Formula (VI): 
       
         
           
           
               
               
           
         
         wherein z is 1, 2, 3, or 4; each R 12  is attached to a carbon atom of the thiophene moiety and independently is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, arylalkyl, fluoroalkyl, fluoroalkenyl, fluoroalkynyl, fluoroaryl, fluoroarylalkyl, a carboxylic anhydride, and a carboxylic ester selected from the group consisting of an alkyl ester, an alkenyl ester, an alkynyl ester, an aryl ester, an arylalkyl ester, a fluoroalkyl ester, a fluoroalkenyl ester, a fluoroalkynyl ester, a fluoroaryl ester, and a fluoroarylalkyl ester; 
         optionally R 12  substituents on two adjacent C atoms together form a cyclic carboxylic anhydride group; and 
         the compound bears at least one R 12  substituent selected from a carboxylic anhydride and a carboxylic ester. 
       
     
     
         24 . The electrolyte of  claim 23  wherein z is 1 or 2 and each R 12  substituent is selected from a carboxylic ester and a carboxylic anhydride, or two adjacent R 12  substituents together form a cyclic anhydride. 
     
     
         25 . The electrolyte of  claim 24  wherein the carboxylic ester is a C 1  to C 4  alkyl carboxylic ester. 
     
     
         26 . An electrochemical cell comprising an anode, a cathode, and an electrolyte of  claim 1  in contact with the anode and the cathode. 
     
     
         27 . A battery comprising a plurality of electrochemical cells of  claim 26  arranged in series, in parallel, or both. 
     
     
         28 . An electrochemical cell comprising an anode, a cathode, and an electrolyte of  claim 7  in contact with the anode and the cathode. 
     
     
         29 . A battery comprising a plurality of electrochemical cells of  claim 28  arranged in series, in parallel, or both.