Improved Electrochromic Display Electrolytes
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
This article describes an electrochromic display device of the kind in which a visually observable persistent deposit of bipyridinium ions, present in solution, is formed on a display electrode upon passage of electric current through the solution between a counter electrode and the display electrode, the solution comprising the following species: bipyridinium cations, supporting electrolyte, cadmium II ions, and sulphamate cations. The cadmium II ions act as catalytic metal ions which undergo electrolytic reduction at a display electrode having a potential more negative than the reduction potential of the bipyridinium cations; cadmium II ions are preferred to the more commonly used thallium I ion.