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All-solid-state Li-ion batteries, have become increasingly important because of their highly reliable solid electrolyte materials. Flexible solid polyethylene oxide (PEO) based electrolytes have been widely studied. Nevertheless, this material exhibits low lithium-ion conductivity. Herein, we report the optimisation of the composition of PEO/polyvinylidene fluoride (PVDF)-based electrolytes to enhance ionic conductivity. When the weight ratio of lithium bis(trifluoromethane sulphonyl)imide and PEO/PVDF is 1:5 (LiTFSI:PEO/PVDF = 1:5), maximum conductivities are 2.98 × 10−5 S cm−1 at 30°C and 5.56 × 10−4 S cm−1 at 60°C. Furthermore, the all-solid-state battery using this solid electrolyte film, a Li metal anode, and a LiFePO4 cathode delivers initial discharge capacities of 149.6 mAhg−1 (0.1 C, 60°C) and 130.2 mAh g−1 (0.5 C, 60°C). Meanwhile, the solid-state lithium battery also presents good cycling performance and excellent rate capability at 60°C. [ABSTRACT FROM AUTHOR]

Solution casting technique has been used to prepared chitosan-based polymer electrolyte films. The polymer electrolyte (PE) film containing 55 wt.% of biopolymer chitosan, 45 wt.% of NH4I salt and 80 wt.% of 1-butyl-3-methylimidazolium iodide (BMII) displayed the highest room temperature ionic conductivity of 3.02 × 10−4 S cm−1. The interaction between components in the biopolymer electrolyte has been optically investigated. The configuration of indium tin-oxide (ITO)/TiO2/Ru-complex (N3) dye/biopolymer electrolyte/Pt/ITO dye-sensitized solar cells (DSSCs) were fabricated. DSSC with chitosan-based PE consist of 80 wt.% BMII exhibited the highest efficiency of 1.2%. [ABSTRACT FROM AUTHOR]

The doping of polymer electrolytes (PEs) with liquid crystal (LC) materials has been shown to improve the performance of dye-sensitised solar cells (DSSCs). This is achieved by promoting ionic conduction and increasing optical path length through multiple-light scattering within the photovoltaic devices. In LCs, it is well known that the length of the alkyl chain plays an important role since the LC morphology and mesophase stabilisation depend strongly on the alkyl group. In this work, liquid crystal-polymer composite electrolytes (LC-PEs) are prepared using nematic LCs with different alkyl chain lengths. The morphology of the LC-PEs is investigated and correlated with their electrical properties. Subsequently, DSSCs are prepared using the LC-PEs as a direct example of its application. It is shown that increasing the alkyl chain length of the LCs reduces the efficiency of the solar devices. The longer alkyl chains are speculated to intertwine, thus trapping the mobile ions and reducing the bulk ionic conductivity. For the same reason, longer alkyl chain LCs are thought to be unable to passivate the TiO2 surface through the adsorption of cyanobiphenyl groups and hence the higher probability of back recombination reaction between the electrons in TiO2 and PE. [ABSTRACT FROM AUTHOR]

New polymer electrolytes (PEs), potentially interesting for solid-state electrochemical devices applications, were synthesized by a solvent casting method using pectin and ionic liquid (IL)N,N,N-trimethyl-N-(2-hydroxyethyl)ammonium bis(trifluoromethylsulfonyl)imide ([N1 1 1 2(OH)] [NTf2]. The resulting electrolytes besides being moderately homogenous and thermally stable below 155°C, they also exhibited good mechanical properties. The SPE membranes were analyzed by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and complex impedance spectroscopy. [ABSTRACT FROM PUBLISHER]

A solid polymer electrolyte based on lithium hydroxide (LiOH) added with polyethylene glycol and polyvinyl alcohol polymers was synthesized by solution casting. The structural variation with respect to loading wt% of LiOH reveals the semicrystalline property of polymer electrolyte. The differential scanning calorimetry data shows the onset of crystalline to amorphous transition, which occurs nearly to the melting peak, for higher salt content. The structural properties and cross-linking between polymer and salt were demonstrated by polarized optical microscopy. The polymer electrolytes were subjected to AC impedance analysis spectra for obtaining the ionic conductivity at different temperature. The charge carriers relax much faster for higher lithium salt concentration based polymer electrolyte and produces higher conductivity. The highest room temperature conductivity 2.63 × 10−5S/cm is obtained for 8 wt% loading of lithium salt based polymer electrolyte, confirming their use in preparation of ion conducting devices. [ABSTRACT FROM AUTHOR]

Polymer electrolyte membranes (PEMs) play a crucial role for use in major polymer-based fuel cell applications. Key PEM properties such as ion conductivity, reactant permeability, and chemical/physical stability are strongly influenced by the chemical structure and processing conditions of PEMs. This paper presents the property measurement techniques of PEMs using stand-alone membranes and membrane electrode assembly (MEA) configurations. PEM properties such as ion exchange capacity, water uptake, ion conductivity, gas/liquid permeability, and chemical/physical stability are discussed with emphasis on measurement techniques. In addition, the measurement techniques for polymer electrolyte in the catalyst layer are briefly discussed. This review may give some insight to polymer scientists when novel PEM materials are designed, prepared, screened, or fine-tuned for advanced fuel cell systems. [ABSTRACT FROM AUTHOR]