Bambang Prijamboedi

SOFC composite electrolyte based on LSGM-8282 and zirconia or doped zirconia from zircon concentrate

The aim of this research is to study zirconia-based electrolyte materials to increase the commercial value of zircon concentrate as a side product of tin mining industries. Synthesis of CaO-Y2O3-ZrO2 (CYZ) and 8mol% Y2O3-ZrO2 (8YSZ) was carried out by solid state reaction. The result shows that ZrO2 presents in tetragonal phase. Doping of Y2O3 into ZrO2 allows a phase transformation from tetragonal into cubic structure with small percentage of monoclinic phase. Meanwhile, doping of CaO-Y2O3 allows a phase transformation into a single cubic phase. These phase transformations enhance the ionic conductivity of the material. Introduction of 10wt% of LSGM-8282 into CYZ (CYZ-L90:10) allows further improvement of inter-grain contact shown by SEM morphological analysis and leads to the enhancement of ionic conductivity.

Revealing the limiting factors that are responsible for the working performance of quasi-solid state DSSCs using an ionic liquid and organosiloxane-based polymer gel electrolyte

We report a study on quasi-solid-state–dye-sensitized solar cells (QSS–DSSCs) with polymer gel electrolytes (PGEs) that are composed of an organosiloxane hybrid polymer gel and imidazolium ionic liquid. The ionic diffusion coefficients of these PGEs are smaller than those of the pure ionic liquid, which may explain the observation of decreased cell performances in the DSSCs using these PGEs. However, from more detailed electrochemical impedance spectroscopy (EIS) studies, there is a strong evidence that the cell performance is also limited by inefficient charge transfer and charge transport inside the mesoporous TiO2 layer. This is indicated by the absence of transmission line characteristics in the observed Nyquist plots. The present experimental results then indicate that the lack of electrolyte penetration into the mesoporous TiO2 layer, due to the PGE rheology behavior caused by the siloxane-based polymer gel used here, is another crucial limiting factor for the photovoltaic performance of DSSCs using this kind of PGE. We consider that this kind of gel phase effect may be also observed in DSSCs using other types of gel electrolytes, including polyionic liquids.

Conductivity and solid state 29 Si NMR studies of apatite-type lanthanum silicate prepared by hydrothermal method

Apatite-type lanthanum silicates are of great interest because of their high ionic conductivity in which it is potential to be used as electrolyte for the solid oxide fuel cell (SOFC) application. In the present work, we report ²⁹Si solid state NMR studies of several doped lanthanum apatite silicates prepared by hydrothermal method. For the undoped apatite La<inf>9.33</inf>Si<inf>6</inf>O<inf>26</inf> three peaks are observed at chemical shifts of ∼−77.8, −80.5 and −82.5 ppm, and doped apatite two peaks are observed at chemical shifts of ∼−77 and 78–80.5 ppm, apatite with the more high conductivity show more complex Si NMR spectra. That is indicating a correlation between the silicon environment and the observed conductivity.

Modeling ionic conduction in γ-Bi 2 VO 5.5

?-Bi2VO5.5 family oxides has potential to play important role in solid oxide fuel cell, especially as the electrolyte due to their high ionic conductivity. In this work, oxide conduction in γ-Bi2VO5.5 is modeled based on bond valence sum (BVS) method. In γ-Bi2VO5.5, there are oxide vacancies at the equatorial position in the perovskite-like layers. These vacancies can facilitate oxide movement. The γ-Bi2VO5.5 model was built in a primitive structure with the entire V coordination in one layer are tetrahedron and entire V coordination in the next layer are octahedron. Oxygen movement, based on BVS result, mainly occurs in equatorial site i.e. on [140] direction. The minimum achieved BVS value was 1.320, which is considered as a site that has large cavity and facilitates oxygen hopping.

Some Considerations On Photocurrent Characteristics Of Poly(alkylthiophene) And Photovoltaic Characteristics Of Poly(alkylthiophene)/ZnO Based Hybrid Solar Cells

Photocurrent characteristics of poly(alkylthiophene) has been investigated in ITO/poly(alkylthiophene)/Au structure by performing the V‐I measurement at various light illumination intensity. The dependence of photocurrent on light intensity was clearly observed in reverse bias condition. The photocurrent characteristics obey a power law dependence on light intensity, which may be related with the electric field dependent charge carrier generation and transport. Photovoltaic characteristics has been investigated in ITO/Al‐doped ZnO/poly(alkylthiophene)/Ag structure. The observed photovoltaic characteristics show the function of this ZnO layer as the acceptor layer. However, the V‐I curve indicates unusual behavior indicating Ohmic‐like characteristic, which is discussed by considering the nano‐morphology and the conductivity properties of the ZnO layer.