Solid Polymer Electrolytes Based on Gellan Gum and Ionic Liquid for Sustainable Electrochromic Devices

Abstract

Materials sustainability is becoming increasingly relevant in every developed technology and, consequently, environmentally friendly solid polymer electrolytes (SPEs) based on gellan gum and different quantities of ionic liquid (IL) 1-ethyl-3-methyl-imidazolium-thiocyanate [Emim]­[SCN] have been prepared and applied in electrochromic devices (ECDs). The addition of the IL does not affect the crystalline phase of gellan gum, and the samples show a compact morphology, surface uniformity, no phase separation, and good distribution of the IL within the carrageenan matrix. The developed SPE are thermally stable up to ∼100 °C and show suitable mechanical properties. The most concentrated sample (39 wt % IL content) reaches a maximum ionic conductivity value of 6.0 × 10–3 S cm–1 and 1.8 × 10–2 S cm–1 at 30 and 90 °C, respectively. The electrochromic device (ECD) was fabricated with poly­(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) as working electrode and the developed SPE was compared with an aqueous 0.1 M KNO3 solution. The electrochromic performance of the electrolyte was assessed in terms of spectroelectrochemistry, demonstrating a fully flexible ECD operating at voltages below 1.0 V. This novel electrolyte opens the door to the preparation of high performance sustainable ECD.

Bio‐Based Solid Electrolytes Bearing Cyclic Carbonates for Solid‐State Lithium Metal Batteries

“…These polymers include poly(lactic acid) [45,46] and polyurethanes due to their high degree of tuneability in mechanical properties and conductivity as highlighted in recent Reviews and articles [13,47–50] . In this context, polymers based on vegetable oils with long fatty acids, [51–53] cellulose, [54] gums, [55] and others similar bio‐derivatives [56,57] are of high interest as potential ion conductors owing to their ether and carbonyl functional groups.…”

An energy-saving, bending sensitive, and self-healing PVA-borax-IL ternary hydrogel electrolyte for visual flexible electrochromic strain sensors

“…[20][21][22] In addition, related studies have shown that gel electrolytes also promote the improvement of electrochromic properties. [23][24][25][26] Hydrogels in gel electrolytes promise brand new applications in exible electronic elds such as stretchable ECDs, 27 ionic skin, [28][29][30][31] so robotics, 32,33 personal healthcare monitoring, 34 drug delivery, 35 articial organs, 36 and wearable electronics [37][38][39] due to their inherent excellent exibility, high optical transparency, high ionic conductivity, and good biocompatibility. PVA hydrogels have been widely studied due to their nontoxicity, biocompatibility, degradability, water retention, and low cost.…”

“…Ionic Liquids (ILs) are ideal electrolytes due to their high electrical conductivity, negligible vapor pressure, non-flammability, wide electrochemical window, and excellent thermal stability. 52 Previous studies found that the addition of ILs enhanced the conductivity of various polymers, such as gellan gum, 25 poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate)/PVA, 53 and poly(vinylidene fluoride- co -hexafluoropropylene). 54 However, the reports of IL-modified PVA-borax dynamically cross-linked polymer matrixes and the mechanism of enhancing their electrical conductivity in previous studies are scarce.…”

“…DT% is dened as the difference between the transmittances of the colored and bleached states of ECDs at a specic wavelength. 21,25 Electrochromic switching response of the ECDs based on PVA-borax-IL 0.3 -AVCOOEt was studied under ambient conditions by alternately applying voltages between −0.6 and 0.0 V at 406 nm with a residence time of 30 s. As shown in Fig. 4e, the ECD exhibited high transmittance (67.2%) in bleached state and low transmittance (1.9%) in colored state with a satisfactory optical contrast as high as 65.3%.…”

Water-Controlled Structural Transition and Charge Transfer of Interfacial Ionic Liquids

“…Ionic liquids (ILs) have been fascinating the scientific community for decades due to their rich spectrum of physical and chemical properties, , which enable a wide range of practical applications from catalysis − to electrochemistry. − They serve as ideal platforms for realizing the green transformation and development of the chemical industry, particularly for the electrocatalytic conversion of CO 2 , in which ILs act as cocatalysts with metal electrodes to reduce the redox potential of CO 2 . , Actually, not only in CO 2 conversion but also in many other chemical reactions, supported IL catalysts (SILCA) and supported catalysts with ILs layer (SCILL) are widely used, where the ILs work by loading on the solid surface and undergo electron transfer with the reactants . Therefore, the interface plays an essential and ubiquitous role in the catalytic process. , It is well-known that contact electrification is a universal electron transfer phenomenon that can occur between any contact materials, , and hence there must be electron transfer between ILs and solid surfaces, which may largely affect the performance of ILs.…”