An electrolyte for an electrochromic display of the kind in which a persistent colored species of an electrochromic substance in solution is deposited onto a display electrode upon the passage of current therethrough is disclosed. The electrolyte comprises an aqueous solution of a di-alkyl bipyridinium...http://www.google.fr/patents/US4376569?utm_source=gb-gplus-shareBrevet US4376569 - Electrolyte for an electrochromic display
