Patent ID: 8462419

Claim:
A composition for electrochromic devices, which comprises (A) a quaternary ammonium salt represented by the following formula (1) or a quaternary phosphonium salt represented by the following formula (2), (B) a supporting electrolyte containing bromide ions, and (C) a solvent containing water as an essential component, wherein (A) is soluble in (C), wherein and wherein, in the formula (1) or (2), R 1 , R 2 , R 3 and R 4 independently represent an unsubstituted or substituted alkyl group having four or more carbon atoms, or an unsubstituted or substituted phenyl group, when the alkyl group or the phenyl group has a substituent, the substituent is halogen or hydroxyl group, and X n− represents an anion selected from halogen ions, hydroxide ion, nitrate ion, sulfate ion, perchlorate ion, tetrafluoroborate ion, phosphate ion, hexafluorophosphate ion, carbonate ion, acetate ion, hydrogencarbonate ion, dihydrogenphosphate ion, hydrogensulfate ion, cyanide ion, thiocyanate ion, sulfite ion, nitrite ion, chlorite ion, hexacyanoferrate(II) ion, and hexacyanoferrate(III) ion.