Influence of LiCl and AgNO3 Doping on the Electrical Conductivity of PVA Flexible Electrolyte Polymer Film

Recently, the electrical conductive electrolyte based on flexible polymeric films have been attracted much attentions, due to their applications in batteries, thermoelectrics, temperature sensors and others. In this regard, two polymeric electrolytes (PVA/LiCl) and (PVA/AgNO3) films have been engineered and the influence of the dopants and the annealing temperature on the structural, morphology and ac and dc conductivities is extensively studied. It was found that the films crystallinity has the order PVA/AgNO3 (49.44%) > PVA (38.64%) > PVA/LiCl (26.82%). Additionally, the dc conductivity of the films is increased with embedding the dopants into the PVA as the order PVA/AgNO3 (13.7 × 10−4 S/cm) > PVA/LiCl (1.63 × 10−5 S/cm) > PVA (1.71 × 10−6 S/cm) at 110 °C. It is also found that there is a sharp increase for σac as the frequency increases up to 107 Hz and also as the temperature increases to 110 °C. However, the order of increasing the σac is PVA/LiCl (155 × 10−3 S/cm) > PVA/AgNO3 (2.5 × 10−5 S/cm) > PVA (2 × 10−6 S/cm) at f = 107 Hz and 110 °C. The values of exponent are 0.870, 0.405 and 0.750 for PVA, PVA/AgNO3 and PVA/LiCl, respectively, and it is increased as the temperature increases for PVA and PVA/LiCl, but it is decreased for PVA/AgNO3. The activation energies Ea are 0.84, 0.51 and 0.62 eV for PVA, PVA/AgNO3 and PVA/LiCl, respectively. Moreover, the values of activation energy for charge carrier migration Em are 0.60, 0.34 and 0.4 eV for PVA, PVA/AgNO3 and PVA/LiCl, respectively. By using a simple approximation, the carrier concentration, carrier mobility and carrier diffusivity are calculated, and their values are increased as the temperature increases for all samples, but they are higher for PVA/LiCl than that of PVA/AgNO3. These results are discussed in terms of some obtained parameters such as hopping frequency, free volume and chain mobility. Interestingly, the conduction mechanism was found to be the electronic charge hopping for PVA and PVA/LiCl films, however it was found to be the ionic charge diffusion (n < 0.5) for PVA/AgNO3 film. It has been predicted that these electrolytic films have a prospective applications in batteries design, temperature sensors, electronic and wearable apparatuses at an affordable cost.

Thermally activated charge transport in carbon atom chains

The conductance of alkanedithiol molecular junctions increases under elevated temperatures due to the contributions of superexchange with inter-chain charge hopping.

Reduced Graphene Oxide Obtained by Hummers and Marcano-Tour Methods: Comparison of Electrical Properties

The aim of this paper is the comparison of structural, morphological and electrical properties of graphene oxide synthesized by Hummers and Marcano-Tour approaches and reduced graphene oxide obtained by hydrothermal hydrazine-assisted route. Obtained materials were characterized by XRD, scanning electron microscopy, low temperature nitrogen absorption and impedance spectroscopy. It was determined that reduced graphene oxide obtained by Hummers route is formed by plate-like agglomerates with respectively short distance between graphene layers that consist of plate-like particles with smaller average diameter and larger average thickness. Reduced graphene oxide that was synthesized by Marcano-Tour method is mesoporous solid material and consists of randomly aggregated linear fragments of carbon packages. It was suggested that dominant charge transport mechanism for both graphene oxide samples was proton conductivity. Both: charge migrating in graphene fragments and the morphologically sensitive charge hopping between them were observed for reduced graphene oxide.

Polynitroxide-grafted-graphene: a superior cathode for lithium ion batteries with enhanced charge hopping transportation

The emergence of organic nitrogen-oxide (NO) radical polymers has brought hope in the pursuit of high performance lithium-ion batteries (LIBs).

Excited state electron and energy relays in supramolecular dinuclear complexes revealed by ultrafast optical and X-ray transient absorption spectroscopy

Complementary ultrafast techniques provide clear observation of charge hopping between metals in dinuclear complexes.