K+-doped poly(ε-caprolactone)/siloxane biohybrid electrolytes for electrochromic devices

Abstract

Sol-gel derived KCF 3 SO 3 -doped di-urethane cross-linked poly(-caprolactone) (PCL(530))/siloxane ormolytes with  > n  0.5 (n indicates the number of (C(=O)(CH 2 ) 5 O) repeat units per K + ion) have been studied. Xerogel samples with n ≥ 1 are thermally stable up to 235 ºC. A minor proportion of PCL crystallites occur in some dilute-to-concentrated samples. At n ≤ 4 a crystalline PCL(530)/siloxane-KCF 3 SO 3 complex with unknown stoichiometry emerges. At n ≤ 2 this complex coexists with pure salt. At temperatures higher than 40 ºC the composition which exhibits the highest ionic conductivity is n = 21. "Free" anions, weakly coordinated CF 3 SO 3 ions, contact ion pairs and several higher ionic aggregates emerge in all the * Solid State Ionics samples. The K + ions bond to the oxygen atoms of the carbonyl groups of the urethane and ester groups, of the PCL (530) ether chain and of the triflate ions at all salt concentrations. The ormolytes were successfully used in the production of prototype electrochromic devices (ECDs) that exhibit low switching time and good open circuit memory.. The ECD incorporating the ormolyte with n = 21 displays an average transmittance in the visible region of ca. 55 % in the colored state and 76 % in the bleached state.

Hybrid Materials and Polymer Electrolytes for Electrochromic Device Applications

“…Polymer electrolytes are an important component of ECDs and the science of polymer electrolytes is interdisciplinary 101–106. The exact formulation of the electrolyte is very important for the cycle life of the device 104–108. The interfaces between the electrolyte and both the electrodes in the ECDs dictate the overall performance of the device 109–111.…”

“…Along with this, electrochemical stability is also one of the most significant requirements that an electrolyte should meet for the long life of the device in electrochromic applications 112–114. For the successful applications of polymer electrolytes in ECDs, the following requirements should be met101–111: High ionic conductivity: Polymer electrolytes should be a good ionic conductor and electronic insulator (σ e <10 −12 S/cm), so that ion transport can be facilitated and self‐discharge can be minimized. It should exhibit electrical conductivity in the range of 10 −3 ‐10 −7 S/cm (depending on applications) in order to achieve the performance level of liquid electrolyte‐based systems.…”

Ion conducting and paramagnetic d-PCL(530)/siloxane-based biohybrids doped with Mn2+ ions

“…5a). This peak, which is associated with ordering of the siliceous domains [47] reveals that the incorporation of the manganese salt did not affect the amorphous character of the non-doped d-PCL(530)/siloxane matrix [7,9]. The POM images of the biohybrids (Fig.…”

“…1) have been tested in the last few years. Doping of this organic-inorganic hybrid matrix with lithium [5][6][7][8], potassium [9], magnesium [10], europium [8], and erbium [6] salts, europium complexes [11] and ionic liquids [5] resulted in materials with attractive features, in particular high ionic conductivity and in the case of the lanthanidecontaining systems also high luminescence, and foreseen applications in eco-friendly ECDs. Prior to these works, applications of PCL and PCL-based hybrids had been proposed almost exclusively for the biomedical field, as biodegradable suture, artificial skin, resorbable prostheses, containers for sustained drug delivery, or bioactive coatings [12][13][14][15][16][17][18][19][20].…”

Zirconium dioxide nanofilled poly(vinylidene fluoride-hexafluoropropylene) complexed with lithium trifluoromethanesulfonate as composite polymer electrolyte for electrochromic devices

“…Thus, a well-tuned formulation is very essential for high efficiency and for longer cycle life of the device [17][18][19][20][21]. For a polymer electrolyte to be suitable for electrochromic applications, it has to be highly ion conductive, has a good electron donating ability, has low bond rotation energy, thermally and electrochemically stable, has high optical transparency, able to cover a wide range of potential, able to be confined into specific areas, and it has to be cheap but environmentally friendly [14][15][16][17][18][19][20][21][22][23][24].…”