Gel polymer electrolyte for reversible metal electrodeposition dynamic windows enables dual-working electrodes for faster switching and reflectivity control

Abstract

Dynamic windows based on reversible metal electrodeposition are an attractive way to enhance the energy efficiency of buildings and show great commercial potential. Dynamic windows that rely on liquid electrolytes are at risk of short circuiting when two electrodes contact, especially at larger-scale. Here we developed a poly (vinyl alcohol) (PVA) gel polymer electrolyte (GPE) with 85% transmittance, that is, sufficiently stiff to act as a separator. The GPE is implemented into windows that exhibit comparable electrochemical and optical properties to windows using a liquid electrolyte. Furthermore, the GPE enables the fabrication of windows with dual-working electrodes (WE) and a metal mesh counter electrode in the center without short-circuiting. Our dual-WE PVA GPE window reaches the 0.1% transmittance state in 101 s, more than twice the speed of liquid windows with one working electrode (207 s). Additionally, each side of the dual-WE GPE window can be tinted individually to demonstrate varied optical effects (i.e., more reflective, or more absorptive), providing users and intelligent building systems with greater control over the appearance and performance of the windows in a single device architecture.

New Anodic Discoloration Materials Applying Energy-Storage Electrochromic Device

“…Following the freeze-thaw process, the PVA gels were immersed in three separate fresh DI water baths for 1 h and were subsequently soaked in DI water for an additional 24 h to remove excess DMSO and form PVA hydrogels. These hydrogels were then immersed in baths containing BiCuClO 4 with a 0.1 wt% PVA additive electrolyte for 24 h, allowing the water in the hydrogel to be replaced with sufficient liquid electrolyte, resulting in the formation of the PVA gel polymer electrolyte (GPE) [44].…”

New Anodic Discoloration Materials Applying Energy-Storage Electrochromic Device

“…Following the freeze-thaw process, the PVA gels were immersed in three separate fresh DI water baths for 1 hour and subsequently soaked in DI water for an additional 24 hours to remove excess DMSO and form PVA hydrogels. These hydrogels were then immersed in baths containing BiCu ClO4 with a 0.1 wt% PVA additive electrolyte for 24 hours, allowing the water in the hydrogel to be replaced with sufficient liquid electrolyte, resulting in the formation of PVA gel polymer electrolyte (GPE) [35].…”

“…The Rct value for Sample 2 is the lowest compared to Mo: WO3/ ITO /glass, which may be due to Sample 2 having a larger enclosed area of the CV curves. This leads to faster charge transfer at the electrode-electrolyte interface [35], which can significantly contribute to larger diffusion coefficients of electrons and Li + ions around the surface of Mo: WO3/ ITO /glass, thus enhancing the electrochemical response [29,42].…”