A new type of electrochemical noise analysis technique with First Fourier Transformation, FFT, was applied to galvanic corrosion of barrier and porous type anodic oxide films formed on aluminum in 0.5 kmol/m3 H3BO4/0.05 kmol/m3 Na2B4O7 solutions with 0.01 kmol/m3 NaCl. During localized corrosion, the current and potential were changed, with fluctuations and the potential and the current fluctuations show good correlation. The slope of the PSD spectra of both types of anodized specimens are about minus one (−1), just after localized corrosion started. This technique allows observation of electrochemical impedance changes during localized corrosion. The impedance spectra are independent of signal frequency and the impedance of porous types anodic oxide film specimens decrease with immersion time and increases with anodizing time.
To increase the first discharge (lithium extraction) efficiency of tin monoxide anode for lithium secondary battery, elemental lithium was added to SnO by mechanical alloying (MA) in advance. The resulting lithiated SnO (LixSnO) electrode was found to exhibit almost 100% of the first discharge efficiency at x=3.2. X-ray and electrochemical analyses revealed that the mechanically lithiated LixSnO appears to contain three phases of Li2O, β-Sn, and Li3.5Sn. Good cycle life performance of the electrode was obtained on the LixSnO/Cu composite.
Perfluorosulfonated ionomer (PFSI) membranes have large applications in industrial electrochemical devices and, for that, several papers can be found in the literature dealing with their work performance and characterization. A vast majority of these follow some pretreatment steps with the membranes in which the main one involves H2O2 treatments at high temperatures, but there is very little study about this pretreatment effect and also if it changes or not the material properties. This work shows by IR and Raman spectroscopic techniques, TG, DSC and DMA measurements, that this treatment indeed changes slightly the PFSI polymer structures and also affects a little its thermal and mechanical properties. PAS-IR measurements show that H2O2 can promote oxidation reactions inside ionomer clusters while ATR-IR shows that, these reactions can cause a little change in its polymeric structure. TG, DMA and DSC analyses show that treated PFSI polymer is slightly more resistant to thermal effects but also becomes slightly more rigid and less plastic. The work also evaluates these effects in three perfluorinated ionomer samples with different equivalent weight (EW) values, showing that the lower the EW, the more pronounced are the treatment effects.
The fabrication of the codeposited film electrode of LiCoO2 and acetylene black (AB) as a binder-free electrode was attempted using the electrophoretic deposition method in order to make a high energy density battery. Based on the ζ-potential measurement, it was found that LiCoO2 and AB particles in an acetone with I2 bath showed positive charge. The binder-free codeposited film consisting of LiCoO2 and AB particles was cathodically electrodeposited on an Al substrate in the acetone with I2 bath including their particles. The LiCoO2 content in the codeposited film was controlled from 68 to 94 wt%. In the cyclic voltammogram of the codeposited film, the oxidation and reduction waves corresponding to the electrochemical intercalation/deintercalation reaction of Li ion were observed. Namely, it was determined that the intercalation/deintercalation reaction of Li ion occurred in the codeposited film. The charge capacity was about 135 mAh g−1 and the discharge capacity was about 125 mAh g−1 when the codeposited film was evaluated as a positive electrode.
The purpose of this investigation was to study electroless Au plating from a sulfite/thiosulfate complex bath (0.015M Na3[Au(SO3)2]+0.1M Na2S2O3+0.4M Na2SO3+0.05M C6H7O6Na+0.18M KOOCCH(OH)CH(OH)COONa) using erythorbic acid as the reducing agent. Deposition rates by autocatalytic reaction and displacement reaction were increased with increasing the concentration of erythorbic acid. The deposition rate by autocatalytic reaction was increased with increasing bath temperature. The deposition rate by displacement reaction was suppressed by the addition of benzotriazole (BTA), di-sodium ethylenediaminetetraacetate (EDTA) and ethylenediamine (en). Electroless Au film which shows a good characteristics in the solder joint strength was obtained from a bath containing BTA, EDTA and en.
We investigated the carrier leakage blocking effect of the magnetron sputtered TiO2 film insertion between transparent anodic electrode and porous TiO2 film in the dye-sensitized solar cell (DSC), as a consequence of preventing the ionic short-circuiting of the electrolyte to the anodic electrode through porous TiO2 film. The optimization of the deposition condition of the high temperature TiO2 sputtering for the carrier leakage blocking is reported.
The effect of water impurity and manganese dioxide coating on reformation of niobium anodic oxide film have been investigated to increase the break down voltage of the solid electrolytic capacitor. We applied the organic electrolyte system of 1 mol·dm−3 LiClO4/EC+DEC (50:50 in volumes) to control the water content, and the steady-state potential was measured by using the chronoamperometry at 1 mA·cm−2. It was concluded that the water was playing an important role to increase the break down voltage of the solid electrolytic capacitor than the manganese dioxide coating.