Fig. 2: EC performance of meso- and compact-WO3 ECSs.

a ECS structure employed in this work. b Transmittance spectra of the meso-WO3 ECS as a function of applied voltages (inset: photographs of the colored and bleached states). c In situ optical responses of the compact-WO3 ECS (red line) and the meso-WO3 ECS (blue line). d Nitrogen adsorption-desorption isotherm curves of the mesoporous and compact WO3. e Pore size distribution of mesoporous WO3. f Optical density variation as a function of injected charge density. g Coloration/bleaching cycling stability of the two ECSs for 1000 cycles.