This paper explores the design of hybrid films consisting of WO3·H2O nanoparticle (WHNP)-embedded chitosan thin films on amorphous WO3 (a-WO3) films for multifunctional electrochromic (EC) energy storage devices. The chemical cross-linking between chitosan and WHNPs resulted in faster switching speeds (4.0 s coloration, 0.8 s bleaching), higher coloration efficiency (62.4 cm²/C), and improved long-cycling retention (91.5% after 1000 cycles) compared to bare a-WO3 films. The hybrid films also demonstrated high specific capacitance (154.0 F/g at 2 A/g) and stable rate capability for energy storage, leading to brighter illumination of a white-light-emitting diode.

Bon-Ryul Koo, Myeong-Hun Jo, Kue-Ho Kim, Hyo-Jin Ahn