A nonaqueous charge-balancing electrolyte with a redox couple (I−/I3−) is investigated to improve the electrochromic (EC) performance of polyoxometalate (POM)-based electrochromic devices (ECDs). PW12O403− (PW12)-coated porous TiO2 nanoparticle films (PWTNF) with different thicknesses are used as the working electrode. The optical contrast (ΔT) of the optimized PW12-ECDs reached 59.4% with the electrolyte containing the I−/I3− redox couple. PW12-ECDs also show a fast response time for bleaching (tb,90% = 1.9 s) and coloration (tc,90% = 3.1 s). On the contrary, without the I−/I3− redox couple, PW12-ECDs show a poor ΔT of 4.0% and slow response times (>9.0 s). The role of the I−/I3− couple is identified as a charge-balancing redox mediator between PW12 and the counter electrode. Li+ is the effective intercalating/deintercalating cation required for the EC reaction of PW12. Thus, by simply introducing the I−/I3− redox couple into the electrolyte significantly boosts the EC performance of POMs.
Bibliographical noteFunding Information:
This research was supported by the National Natural Science Foundation of China (no. 21501084), the General Scientific Research Project of the Educational Department of Liaoning Province (LFW201904), and Global Research Laboratory (GRL) through the National Research Foundation of Korea (NRF) (No. 2016K1A1A2912753).
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Industrial and Manufacturing Engineering