ABSTRACT
To achieve both high structural integrity and excellent ion transport, designing ion gel polymer electrolytes (IGPEs) composed of an ionic conducting phase and a mechanical supporting polymer matrix is one of the promising material strategies for the development of next-generation all-solid-state energy storage systems. Herein, we prepared an IGPE thin film, in which an ion-diffusing phase containing ionic liquids and lithium salts was bicontinuously intertwined with a cross-linked epoxy phase, using a silicon elastomer-based stamping method, thus producing a homogeneous IGPE-based thin film with low surface roughness (Rrms = 0.5 nm). Following the optimization of the IGPE thin film in terms of the concentrations of ionic constituents, the film thickness, and various process parameters, the IGPE itself showed a high ionic conductivity of 0.23 mS/cm with a low activation energy for lithium-ion transport, as well as the high capacitance of approximately 10 µF/cm2 based on the metal-insulator-metal configuration. Furthermore, an all-solid-state supercapacitor containing two IGPE coating-activated carbon electrodes produced using our poly(dimethylsiloxane) (PDMS) stamping method exhibited high energy and power densities (44 W h/kg at 875 W/kg and 28 kW/kg at 3 W h/kg). It was also found that this supercapacitor showed a dramatic reduction (more than 50%) of the current-resistance (IR) drop, which is an indicator of low interface resistance, while maintaining the initial electrochemical performance even after severe mechanical deformation such as bending or rolling. Therefore, all these results support the fact that our developed PDMS stamping method enables the rendering of a high-performance ion gel polymer thin-film-based electrolyte with acceptable stability and mechanical flexibility for all-solid-state wearable energy storage devices.
ABSTRACT
A series of dicationic imidazolium bis(tetrafluoroborate) salts were newly synthesized, and their phase transition behaviors were correlated with thermal, scattering, optical and conductivity results. The bis-imidazolium salts having side-chain lengths of C6-C10 showed plastic crystal mesophases, while a liquid crystal mesophase was formed in the bis-imidazolium salts with long side-chains (C11 and C12). Soft plastic and liquid crystalline phases were also confirmed by wide-angle X-ray diffraction. For the bis-imidazolium salts exhibiting a plastic crystal mesophase, the ionic conductivity suddenly increased at the melting temperature. However, the bis-imidazolium salts with long side-chains showed a slope increase during the liquid crystal-liquid crystal transition.
ABSTRACT
The effects of terpenes on the release and permeation of ofloxacin and lidocaine from moisture-activated composite patches were investigated. Ofloxacin without enhancers showed very low permeation rate (0.58 microg/cm(2)/hr), and the addition of cineole enhanced the permeation flux 14.1-times; /-menthol and d-limonene increased it 4.7- and 3.5-times, respectively. The highest permeation flux (77.7 +/- 25.3 microg/cm(2)/hr) of lidocaine from the composite patches was also achieved when cineole at the concentration of 0.33% in the gel base was added. /-Menthol also revealed enhancing effect on the permeation of lidocaine; however, d-limonene failed to increase the permeation rate of lidocaine. In conclusion, for effective moisture- activated patches containing lidocaine and ofloxacin, cineole could be used as an effective and safe enhancer.
