Electrochemical Impedance Spectroscopic Analysis on the Electrochemical Deposition of Lead Dioxide in Acidic Medium

Electrochemical deposition of pure lead dioxides and modified lead dioxides incorporated with As(V) on a gold electrode was investigated by cyclic voltammetric, in-situ electrochemical impedance spectroscopic, and reflective UV-vis spectroelectrochemical techniques. The focus was given to analyze electrochemical impedance spectroscopic data obtained under various deposition conditions, i.e.,different deposition potentials.     

Electrochemical properties of polyaniline-modified sodium vanadate nanomaterials

Sodium vanadate nanomaterials were synthesized at different pH-values of a sodium hydroxide solution of vanadium pentoxide. Polyaniline-modified sodium vanadate nanomaterials were prepared at room temperature and at 3°C by a chemical polymerization method. The crystal structure and phase purity of the samples have been examined by powder XRD. The samples were identified as HNaV₆O₁₆⋅4H₂O and Na_1.1V₃O_7.9. The electrochemical measurements show that polyaniline-modified sodium vanadate hydrated nanomaterials provide higher current density than the sodium vanadate nanomaterials.     

Self-assembly of LiFePO4 nanodendrites in a novel system of ethylene glycol–water

In this work, a novel system of ethylene glycol/water (EG/W) was employed to synthesize LiFePO₄, in which dodecyl benzene sulphonic acid sodium (SDBS) was used as soft template to control particle morphology. The samples were characterized by X-ray diffractometer (XRD), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDX). The LiFePO₄ sample obtained by the reported method displays interesting hierarchical nanostructure (i.e. nanodendrites), which was constructed by nanorods of 3–5 μm in length and ∼50 nm in diameter. The EG/W ratio, amount of SDBS added, hydrothermal temperature and duration played important roles in the assembly of the hierarchical nanostructures. A formation mechanism was proposed and experimentally verified. It is concluded that the nanodendrites were formed due to the end-to-end self-assembly of nanorods. Compared to previously reported methods, the reported approach shows obvious advantages of one-step synthesis, environmental friendliness and low cost, to name a few. The nanodendrites as a cathode material have a higher capacity, compared with the other samples.