Transparent Metal–Organic Framework-Based Gel Electrolytes for Generalized Assembly of Quasi-Solid-State Electrochromic Devices

Abstract

Metal–organic framework (MOF)-based electrolytes under gel/solid states have been widely used for electrochemical devices recently due to their designable metal centers/ligands and diffusion channels in the porous structures. Therefore, it is always desired to apply the MOF-based electrolytes in electrochromic (EC) fields. Yet, challenges exist in realizing their high optical transparency to satisfy the unique optical requirements of EC devices. Herein, a transparent MOF-based gel electrolyte (MGE) is demonstrated through the incorporation of 2-methylimidazole among MOF nanocrystals to prevent the strong light scattering of MOF nanocrystals. As a result, the gel electrolyte showed an improved average transmittance of ca. 82.2% compared with the MOF electrolytes without 2-methylimidazole (ca. 59.2%). In addition, because of the designed large channels in the porous MOF structure, the gel electrolyte exhibited a high ionic conductivity of 2.66 × 10–3 S cm–1. At last, we used the transparent MGEs to assemble two types (rigid and flexible) of quasi-solid-state EC devices based on inorganic WO3 and organic poly­(3,4-ethylenedioxythiophene) (PEDOT), respectively. Both devices showed great EC performances, and the flexible devices exhibited high mechanical stability under the bending state or even after being cut and punched, advancing the general applications of our transparent MGEs in EC fields.

Synergistic Solvation and Interface Regulations of Eco‐Friendly Silk Peptide Additive Enabling Stable Aqueous Zinc‐Ion Batteries

“…Compared with the additives above, silk and its derivatives (fibroin and sericin), as eco‐friendly natural products, show a relatively low price and contain abundant polar groups as active sites for interactions with metal ions. [ 30–36 ] For example, silk fibroin was used to modify separators of Li metal batteries, facilitating the homogeneous deposition of Li + on the anode surface. [ 31 ] Silk sericin was employed as a protective layer on Li metal anode to suppress the dendrite growth of Li‐S batteries.…”

Electrochemical Actuators with Multicolor Changes and Multidirectional Actuation

“…The valence state change of the V element before and after the reaction is proved, which indicates that the dualresponsive composite film has good electrochromic properties. [29][30][31] In addition, a spectrophotometer and fiber-optic UVvis spectrometer were used to measure the color of the actuator at different redox states. As shown in Figure 1g, under a Small 2022, 18, 2107778 voltage of +1 V, the color of composite film was yellow, and then changed to yellow-green under 0 V and dark turquoise-blue under −1 V. [32][33][34] The oxidized and reduced dual-responsive composite films with Commission International de I' Eclairage (CIE) chromaticity are shown at the coordinates of (0.44, 0.485), (0.36, 0.465), and (0.33, 0.415) in Figure 1g.…”

An electrophoretic e‐paper device with stretchable, washable, and rewritable functions

“…As another critical component of the reflective display, the transparent and stretchable electrodes have been explored by numerous studies. [24][25][26] Recently, various transparent and conductive materials have been used for flexible and transparent electrodes of optoelectronic devices, such as carbon nanotubes, graphene, conductive polymer, ionic conductors, and metal-oxide. [27][28][29] From the manufacturing process to the conductive materials, our group has also investigated the self-cracking fabrication and assembled the conductive material into the channel using hydrophilic, hydrophobic treatment, improving the maximum strain tolerance of the transparent, stretchable electrode while maintaining the conductivity.…”

“…As another critical component of the reflective display, the transparent and stretchable electrodes have been explored by numerous studies 24–26 . Recently, various transparent and conductive materials have been used for flexible and transparent electrodes of optoelectronic devices, such as carbon nanotubes, graphene, conductive polymer, ionic conductors, and metal‐oxide 27–29 .…”