Gellan‐Gum and LiTFSI‐Based Solid Polymer Electrolytes for Electrochromic Devices. Issue 20 (26th May 2021)

• Record Type: Journal Article
• Authors: Isfahani, Vahideh Bayzi; Pereira, Rui F. P.; Fernandes, Mariana; Sabadini, Rodrigo C.; Pereira, Sónia; Dizaji, Hamid Rezagholipour; Arab, Ali; Fortunato, Elvira; Pawlicka, Agnieszka; Rego, Rosa; de Zea Bermudez, Verónica; Silva, Maria M.
• Is Part Of: ChemistrySelect. Volume 6:Issue 20(2021)
• Page Start: 5110
• Page End: 5119
• Publication Date: 2021-05-26
• Subjects: Electrochromic devices -- Gellan gum -- LiTFSI-based SPE -- Prussian blue.; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.202004614
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: It has been long recognized that solid polymer electrolytes (SPEs) are potentially interesting for solid‐state electrochemical devices. Gellan gum (Ge)‐based SPEs, plasticized with glycerol (Gly) and doped with lithium bis(trifluoromethanesulfone)imide (LiTFSI) were prepared by the solvent casting technique, and their properties were evaluated. LiTFSI‐based SPE systems exhibit, on the average, higher conductivities than similar systems with other lithium salts. The structure, morphology, complex impedance spectroscopy, cyclic voltammetry and thermal stability of the new electrolyte system were characterized. Electrochromic devices (ECDs) were built with optimized electrolyte samples and their performance was analyzed. The samples were applied in small ECDs with glass/ITO/CeO2 ‐TiO2 /SPE/Prussian blue/ITO/glass configuration. The devices presented a two‐modulation operation: a semi‐bright mode (−2.5 V) and a dark mode (+0.5 V). The best results were obtained with the ECD containing the GeGly1 Li2.4 electrolyte, for which the transmittance (T) values in the bleached and colored states were ca. 33.4/43.0 % and 5.4/8.8 % at 555/1000 nm, respectively. These results correspond to ΔT and ΔOD values of 28.0/34.2 % and 0.79/0.69, respectively, which give quite high CEin and CEout values of −4925 cm 2 C −1 for bleaching (Qin =−272.1 μC cm −2 ), and 2062 cm 2 C −1 for coloring (Qout =650.0 μC cm −2 ), at 630 nm. This electro‐optical performance suggests that the proposed SPE systems are promising materials to be further investigated and applied in ECDs. Abstract : Solid polymer electrolytes (SPEs) are of great technological relevance for solid‐state electrochemistry, in particular for smart windows. Their synthesis involves the dissolution of an ionic guest species (an ionic salt and/or an ionic liquid) in a host polymer (natural host polymers instead of synthetic ones). Promising SPEs, Gellan‐Gum and LiTFSI‐based, for electrochromic devices have foreseen application in the windows of future buildings of smart cities.