The use of electrochromic windows to control heating and cooling loads in buildings and automobiles have attracted a lot of attention as a new and emerging strategy towards energy saving and energy storage to combat global warming and the energy crisis. The types of electrolyte salts employed in an electrochromic device is of great significance to the charge transfer which are in the form of ions between the electrodes. Thus, the electrolyte salt must be viewed as inert component of the electrochromic cell and it should be stable towards the cathode and anode. Hence, we conducted a comprehensive studies based on experiments on the effects of different salts in gel polymer electrolytes on the performance of electrochromic cells consisting of WO₃/ITO as the working electrode and NiO/ITO as the counter electrode. Three different salts, 1M LiClO₄, 1M LiFSI and 1M LiTFSI in propylene carbonate(PC)/polyethylene glycol diacrylate (PEGDA, Mn: 575) (7/3, v/v) were used in this study. Their ionic conductivities as well as the color changing behavior in the electrochromic cell were investigated.

Acknowledgements

This work was supported by the *Energy Technology Program  of the Korea Institute of Energy Technology Evaluation and Planning(KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20142010102980)