Deep eutectic solvent‐based gel electrolytes for flexible electrochromic devices with excellent high/low temperature durability

Abstract

With the increasing interest in the application of electrochromism to flexible and wearable electronics in recent years, flexible electrochromic devices (ECDs) that can function at extreme temperatures are required. However, the functionalities of flexible ECDs are severely hampered by the inadequate choice of electrolytes, which might ultimately result in performance fading during low-and high-temperature operations. Here, we develop a deep eutectic solvent (DES)-based gel electrolyte that can maintain its optical, electrical, and mechanical properties over a wide range of temperatures (À40 to 150 C), exhibiting an extremely high visible-range transmittance over 90%, ion conductivity of 0.63 mS cm À1 , and fracture strain exceeding 2000%. Owing to the excellent processability of the DES-based electrolytes, provided by dynamic interactions such as the lithium and hydrogen bonding between the DES and polymer matrix, a directly written patterning in ECDs is realized for the first time. The fabricated ECDs exhibit an excellent electrochromic behavior superior to the behavior of the ECDs fabricated with traditional gel electrolytes.The introduction of such DES-based electrolytes is expected to pave the way for a widespread application of electrochromic products.

Colorful Electrochromic Displays with High Visual Quality Based on Porous Metamaterials

“…Finally, after curing for 30 s using a 20 W ultraviolet lamp, the electrolyte is solidified, which simultaneously binds the counter and working electrodes. [ 20 ] It should be noted that adding the liquid electrolyte changes the color of the device, but the initial color is restored upon UV curing (Figures S2, S3, Supporting Information).…”

A Scalable, Robust Polyvinyl‐Butyral‐Based Solid Polymer Electrolyte with Outstanding Ionic Conductivity for Laminated Large‐Area WO3–NiO Electrochromic Devices

“…The tensile stress–strain curve of BK10 (Figure S6, Supporting Information) indicated its tensile strength to be 0.47 MPa; this value is slightly higher than that (0.35 MPa) of a novel deep‐eutectic‐solvent‐based gel electrolyte using the similar tensile test. [ 50 ] Ionic conductivity (σ; S cm −1 ), which is a key parameter that dictates the application potential of ECD electrolytes, can be calculated as follows: $$\[ \begin{array}{*{20}{c}}{\sigma = \frac{l}{{S{R_{\rm{b}}}}}}\end{array} \]$$where l is the SPE foil thickness (cm), S is the area of the electrode (cm 2 ), and R b is the bulk resistance (Ω) measured via electrochemical impedance spectroscopy (EIS). The ionic conductivity of the cross‐linked KH560‐modified PVB‐SPE foils with different KH560 concentrations was determined at RT (Figure 3d).…”

“…The tensile stress-strain curve of BK10 (Figure S6, Supporting Information) indicated its tensile strength to be 0.47 MPa; this value is slightly higher than that (0.35 MPa) of a novel deep-eutectic-solvent-based gel electrolyte using the similar tensile test. [50] Ionic conductivity (σ; S cm −1 ), which is a key parameter that dictates the application potential of ECD electrolytes, can be calculated as follows:…”

Resonant‐Cavity‐Enhanced Electrochromic Materials and Devices

“…Therefore, future research should focus on the development of multicolor all-solid-state electrochromic devices, [12] the exploitation of new device structures, [17,111] and the development of improved electrolytes. [100] Finally, resonant-cavity-enhanced electrochromic materials and devices need to be further cross-integrated with other advanced technologies to broaden the application scenarios. 1) For integration with advanced display technologies, for example, LCDs, [228,291] more research and engineering work is needed before practical applications become possible.…”