Rechargeable Zn^2+/Al³⁺ dual-ion electrochromic device with long life time utilizing dimethyl sulfoxide (DMSO)-nanocluster modified hydrogel electrolytes

Abstract

Despite recent advances in hydrogel electrolytes for flexible electrochemical energy storage, ion conductors still exhibit some major shortcomings including low ionic conductivity and short lifetimes. As such, for applications in electrochromic batteries, a transparent, highly conductive electrolyte based on a dimethyl-sulfoxide (DMSO) modified polyacrylamide (PAM) hydrogel is being developed and implemented in a dual-ion Zn 2+ /Al 3+ electrochromic device consisting of a Zn anode and WO 3 cathode.Gelation in a DMSO : H 2 O mixed solvent leads to highly increased electrolyte retention in the hydrogel and prolonged life time for ionic conduction. The hydrogel-based electrochromic device offers a specific charge capacity of 16.9 mAh cm À2 at a high current density of 200 mA cm À2 while retaining 100% coulombic efficiency over 200 charge-discharge cycles. While the DMSO-modified electrolyte shows ionic conductivities up to 27 mS cm À1 at room temperature, the formation of DMSO : H 2 O nanoclusters enables ionic conduction even at temperatures as low as À15 C and retention of ionic conduction over more than 4 weeks. Furthermore, the electrochromic WO 3 cathode gives the device a controllable absorption with up to 80% change in transparency. Based on low-cost, earth abundant materials like W (tungsten), Zn (zinc) and Al (aluminum) and a scalable fabrication process, the introduced hydrogel-based electrochromic device shows great potential for next-generation flexible and wearable energy storage systems.

A fast self-charging and temperature adaptive electrochromic energy storage device

“…Therefore, a novel integrated device structure of the PANI thin lm with a porous structure is expected to achieve excellent electrochemical properties. However, different from the existing work, 23,29,[47][48][49][50][51][52][53][54][55] a water-in-salt type hydrogel electrolyte lled with ZnCl 2 was developed to concurrently improve the energy storage capacity and expand the operating temperature of the device. Fig.…”

Development of xanthan gum‐based solid polymer electrolytes with addition of expanded graphite nanosheets

“…The transparency of a polymeric electrolyte is a requirement for application in some electrochemical devices. 65,66 The UV-Vis spectra for the XG-based electrolytes containing of 0%, 0.1%, 0.3%, 0.5%, and 0.7 wt % of GNs are shown in Figure 4. The samples were approximately 1.03 mm thick and they were measured with a digital caliper.…”

Electrochromic Materials Based on Ions Insertion and Extraction

“…Elezzabi et al proposed a novel Zn‐PB electrochromic battery system which has good compatibility between the dynamic transparent control and the electric energy storage. [ 140 ] To find an optimum dual‐ion electrolyte, they investigated Zn 2+ electrolyte, Al 3+ /Zn 2+ , and K + /Zn 2+ dual‐ion electrolytes for comparison. They found that PB cathode in 1 m ZnSO 4 ‐KCl exhibited a fast‐self bleaching behavior, with the self‐bleaching time of 2.8 s, which was the fastest switching time reported in ZnECMs to date.…”