Sharif Digital Repository

Charge-discharge rate capability is one of the most important properties of cathode materials for lithium batteries, in particular when envisaging high power density applications such as automotive applications. Efforts to modify rate have been carried out by carbon coating and decreasing particle size in order to modify electronic and ionic conductivity. However, this approach cannot justify all experimental data reported in the literature. Here, we investigated the rate capability of cathode materials by considering their density of states (DOS) calculated by several density functional theory (DFT) methods, in both the lithiated and the delithiated case. We suggested that these structures... 

A new poly (acrylonitrile) (PAN)-based gel polymer electrolyte (GPE) is fabricated to study the effect of carbon nanotube (CNT) on dye-sensitized solar cell (DSSC) efficiency. The GPEs are examined using electrochemical impedance spectroscopy (EIS) to analyze ionic conductivity. A maximum of 4.45 mS cm−1 ionic conductivity is achieved at room temperature with incorporation of 11 wt.% CNT. Performance of DSSC is examined with a solar simulator, and the highest energy conversion efficiency of 8.87% is achieved with the addition of 11 wt.% CNT. All GPE samples are found to follow Arrhenius model with temperature-dependent ionic conductivity testing. Structural properties are also characterized... 

A new poly (acrylonitrile) (PAN)-based gel polymer electrolyte (GPE) is fabricated to study the effect of carbon nanotube (CNT) on dye-sensitized solar cell (DSSC) efficiency. The GPEs are examined using electrochemical impedance spectroscopy (EIS) to analyze ionic conductivity. A maximum of 4.45 mS cm −1 ionic conductivity is achieved at room temperature with incorporation of 11 wt.% CNT. Performance of DSSC is examined with a solar simulator, and the highest energy conversion efficiency of 8.87% is achieved with the addition of 11 wt.% CNT. All GPE samples are found to follow Arrhenius model with temperature-dependent ionic conductivity testing. Structural properties are also characterized... 

Molecular dynamics simulations of four ionic liquids (ILs) based on the [Tf2N] bis(trifluoromethanesulfonyl)imide anion, and imidazolium cations with different alkyl side chains have been performed. These simulations investigate the influence of butyl side chain elimination, tail amine functional addition, and C2 methylation on the dynamics and transport properties of this family of ionic liquids at 400 K. In our earlier work (J. Chem. Eng. Data, 2014, 59, 2834-2849), a suite of thermodynamic quantities and microscopic structures of these ILs were studied by classical molecular dynamics simulations and ab initio calculations. In this work, the dynamics of the ILs are studied by calculating... 

Na3MnCO3PO4 (NMCP) particles were synthesized via ball milling of Mn(NO3)2.4H2O, Na2HPO4.2H2O and Na2CO3.H2O powders. The particles were anchored onto reduced graphene oxide (rGO) sheets during hydrothermal reduction process under stirring. Materials produced were characterized by x-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric (TG) measurement and galvanostatic charge/discharge tests. Results showed that dissolution of ball milling products in DI water is an effective method for separation of NMCP from byproducts. Best milling time for production of pure NMCP of minimum particle... 

In this study, Li2O-TiO2-P2O5-x(Fe2O3) (x = 0, 2.5, 5 and 7.5 weight part) glass and glass-ceramics were synthesized through conventional melt-quenching method and subsequently heat treatment. Glass samples were studied by UV–visible spectroscopy and crystallized samples were characterized by differential thermal analysis, X-ray diffractometry and field emission scanning electron microscopy. Besides, electrical properties were examined according to the electrochemical impedance spectroscopy techniques. Experimental optical spectra of the Fe2O3-doped glasses revealed strong UV absorption band in the range of 330–370 nm, which were attributed to the presence of Fe3+ ions. The major crystalline... 

Naphthalimide derivatives provide highly versatile self-assembled systems and aggregated forms with fascinating emission properties that make them potential candidates for many applications such as bioimaging and sensing. Although various aggregated species of naphthalimide derivatives have been well documented, little is known about the correlation between their structure and photophysical properties. Here the preparation of a series of tetrameric naphthalimide molecules in which naphthalimide units are linked by bis-N-heterocyclic carbene complexes of coinage metals is described. An in-depth structural investigation into these tetramers has been carried out in solution and the solid state...