Effect of counter electrode reaction on coloration properties of phthalate-based electrochromic cell

We investigated the effect of counter electrode reaction on the coloration properties of phthalate-based electrochromic (EC) cells using various counter materials. Although the coloration characteristics of dimethyl terephthalate (DMT) cells were improved using a counter material of ferrocene, an organic-based counter material could not endure the overload because of the high reduction potential of DMT. On the other hand, a DMT cell using an inorganic counter material showed good long-term switching stability. As a result, we achieved good switching stability over 5000 cycles for the phthalate-based EC cell with NiO as the counter material.