P‐7.11: Assistance of Iron (II) Chloride and Dimethyl Sulfoxide to Liquid Electrochromic Device Based on Ammonium Metatungstate

Inspired by some previous surveys, we obtained significant electrochromic properties by hydrothermal synthesis using a solution of Iron (II) Chloride, Ammonium Metatungstate, Sodium Hydroxide and Hydrochloric Acid. The respond time of the electrochromic device was accelerated by iron (II) chloride that the coloring time was 6.5s while the bleaching time was 11.5s at the molar concentration ratio of 1:3.5 between ammonium metatungstate and iron (II) chloride, PH=2.5. Meanwhile the device had a significant optical modulation of 65% with air serving as a blank. Influenced by the acidic environment, the aqueous solution will occur hydrogen evolution reaction (HER) which dramatically deteriorated the stable of active layer over a long period of cycling. Here we innovatively apply a hydrogen bond acceptor, dimethyl sulfoxide (DMSO) to the formulation, the open circuit voltage of HER can be increased as well as the overpotential through restricting all hydrogen atoms of the water molecules in the DMSO‐H2O H‐bond network which can achieve the effect of maintaining a steady cycle of over 800 cycles.