The electrochromic performance testing is conducted via the VMP3 (BioLogic Inc.). For the constant potential electrodeposition process, the deposit potential is -0.6 V (versus Ag/AgCl) for 3-electrode system and -0.7 V (versus Cu foil) for 2-electrode device. For the constant potential stripping process, the potential is +0.3 V for 3-electrodes (versus Ag/AgCl) and +1 V for 2-electrodes (versus Cu foil) systems. The cyclic voltammetry test is scanned with a rate of 20 mV/s.