Electrochromic salts, solutions, and devices
View Patent ↗Electrochromic salts. Electrochromic salts of dicationic viologens such as methyl viologen and benzyl viologen associated with anions selected from bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide are produced by metathesis with the corresponding viologen dihalide. They are highly soluble in molten quarternary ammonium salts and together with a suitable reductant provide electrolyte solutions that are used in electrochromic windows.
1. An electrochemical device comprising:
(a) a chamber for receiving an electrolyte solution;
(b) at least one anode in contact with said electrolyte solution in said chamber;
(c) at least one cathode in contact with said electrolyte solution in said chamber; and
(d) an electrolyte solution comprising a molten salt solvent comprising at least one anion selected from the group consisting of bis bis(perfluoroethylsulfonyl)imide and tris(trifluoromethylsulfonyl)methide; at least one reductant soluble in said molten salt solvent, said reductant comprising at least one phenazine; and at least one oxidant soluble in said molten salt solvent, said oxidant having the chemical formula [A][B] 2 wherein B is selected from the group consisting of bis(perfluoroethylsulfonyl)imide and tris(trifluoromethylsulfonyl)methide and wherein A is a dication having the structural formula
wherein R 1 and R 1′ are independently selected from alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;
wherein R 2 , R 2′ , R 3 and R 3′ are independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;
or wherein A is a dication having the structural formula
wherein R 4 and R 4′ are independently selected from alkyl having 1-20 carbons; wherein R 5 , R 5′ , R 6 , R 6′ , R 7 , R 7′ , R 8 , and R 8′ are independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, tnfluoromethyl-substituted aryl having 7-20 carbons.
2. The electrochemical device of claim 1 , wherein A is a dication having the structural formula
wherein R 1 ′ is alkyl having 1 to 9 carbons or trimethylphenyl or methoxyphenyl and R 1 is alkyl having 1 to 9 carbons and R 2 =R 2 ′=R 3 =R 3 ′=hydrogen; wherein R 1 =R 1 ′=m-xylyl and R 2 =R 2 ′=R 3 =R 3 ′=hydrogen; wherein R 1 is phenyl and R 1 ′ is alkyl substituted aryl having 18 carbons and R 2 =R 2 ′=R 3 =R 3 ′=hydrogen; wherein R 1 =R 1 ′=methyl and R 2 is alkyl substituted aryl having 8 or 9 carbons or alkyl having 6 carbons and R 2 ′, R 3 , and R 3 ′ independently selected from the group consisting of hydrogen, alkyl having from 1 to 9 carbons, and alkyl substituted aryl having from 7-20 carbons.
3. The electrochemical device of claim 1 , wherein R 2 =R 2 ′=R 3 =R 3 ′=hydrogen and wherein R 1 and R 1′ are independently selected from alkyl having 1-9 carbons, aryl, and alkyl-substituted aryl having 7-20 carbons.
4. The electrochemical device of claim 1 , wherein R 2 =R 2 ′=R 3 =R 3 ′=hydrogen and wherein R 1 =R 1′ and are selected from the group consisting of alkyl having 1-9 carbons, aryl, and alkyl-substituted aryl having 7-20 carbons.
5. The electrochemical device of claim 1 , wherein R 2 =R 2 ′=R 3 =R 3 ′=hydrogen and wherein R 1 =R 1′ and are selected from methyl and benzyl.
6. The electrochemical device of claim 1 , wherein said phenazine is selected from the group consisting of N,N,N,N′-tetramethyl-p-phenylenediamine, 2,5,10-trimethyl-3-phenyl-5,10-dihydrophenazine, 5-ethyl-10-methyl-5,10-dihydrophenazine, 5,10-dimethyl-5,10-dihydrobenzo(A)phenazine, 2,7-diphenoxy-5,10-dimethyl-5,10dihydrophenazine, 2-phenoxy-5,10-dimethyl-5,10-dihydrophenazine, 2,7-bis(o-tolyl)-5,10-dimethyl-5,10-dihydrophenazine, 2,3-dimethyl-7-trifluoromethyl-5,10-diethyl-5,10-dihydrophenazine, 5,10-dimethyl-5,10-dihydrophenazine, 2,3-diphenyl-5,10-dimethyl-5,10-dihydrophenazine, 2,7-diphenyl-5,10-dimethyl-5,10-dihydrophenazine, 2-vinyl-5,10-dimethyl-5,10-dihydrophenazine, 2-phenyl-5,10-dimethyl-5,10-dihydrophenazine, 5,10-diisopropyl-5,10-dihydrophenazine, 5,10-dimethyl-5,10-dihydrodibenzo(A,C)phenazine, 1,5,10-trimethyl-2-phenyl-5,10-dihydrophenazin, 2,3,5,10-tetramethyl-7-trifluoromethyl-5,10-dihydrophenazine, and 2,3,5,10-tetramethyl-5,10-dihydrobenzo(B)phenazine.
7. The electrochemical device of claim 1 , wherein said electrolyte solution does not include chloride anion, bromide anion, iodide anion, perchlorate anion, tetrafluoroborate anion, tetraphenylborate, carboxylate anion, carbonate anion, hexafluorophosphate anion, or hexafluoroantimonate anion.
8. The electrochemical device of claim 1 , wherein said molten salt comprises cations selected from the group consisting of ammonium cations.
9. The electrochemical device of claim 8 , wherein said quaternary ammonium cations comprise pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, triazolium, tetraalkylammonium cations, or N-methyl morpholinium cations, or mixtures thereof.
10. The electrochemical device of claim 9 , wherein said quaternary ammonium cations have the formula (CH 3 CH 2 ) 3 N(R 24 ), wherein R 24 is alkyl having 2-10 carbons; or having the formula (CH 3 ) 2 (CH 3 CHCH 3 )N(R 25 ), wherein R 25 is alkyl having 2-10 carbons: or having the structural formula
wherein R 26 is alkyl having 2-10 carbons; or having the structural formula
wherein R 27 is alkyl having 2-10 carbons.