Azilah Abd Rahman

Li2CO3 – Al2O3 Composite Solid Electrolytes Prepared by Sol Gel Method

Composite solid electrolytes in the system (1-x)Li2CO3-xAl2O3, where x = 0.1–0.7 were prepared by sol gel method using lithium carbonate and aluminum oxide precursors in ethanol. The gels obtained due to the addition of citric acid were calcined at 80 and 100 oC. Their structural, thermodynamic and electrical properties were investigated by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and impedance spectroscopy. The results indicated that interface phases of crystalline and amorphous exist in this composite system of (1-x)Li2CO3-xAl2O3. The presence of the interface phases are due to the chemical and physical interactions between both crystalline Li2CO3 and Al2O3. The Arrhenius plot of the composite system showed non-linear curves and reached maximum values of ∼10−4 - 10−5 S cm-1 at 150 -180 °C. Based on the results of this study, it can be concluded that the sol gel method used in the preparation of the composite system, has an important role to crystal morphology changes that results in high ionic conductivity.

Effect of Detergent on the ZnO Nanorods Structures Synthesized via the Sol-Gel Method

ZnO is known as an inorganic material that has a variety of morphologies. The morphologies of the ZnO are much influenced by the synthesis route. In this work, two ZnO nanomaterials were prepared by the sol-gel route and the effect of detergent on the morphology and optical band gap of ZnO materials were investigated. The synthesized ZnO materials were characterized using Simultaneous Thermogravimetric Analyzer (STA), X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM). The UV-Vis spectrophotometer is used to determine the optical band gap. The results show that the presence of detergent affected the morphology of the ZnO from nanorods to nano-flakes. The band gap energy of the ZnO were also reduced from 3.14 ev to 2.98 eV from the nanorod to the nanoflakes.

Electron Diffusion in ZnO Nanomaterial: An Ac Impedance Investigation

ZnO is a wide band gap semiconductor with many applications such as in solar cells, varistors, and other electrical components. The ZnO material was synthesized using a sol-gel method. The material was characterized using X-Ray diffraction (XRD) and scanning electron microscopy (SEM). The material is pure and single phase. Electron conduction in ZnO nanomaterials was done using alternating current (ac) impedance. The frequency ranges of the measurements used were 1x 10-3 Hz to 1x 106 Hz and the ac impedance measurements were done within a temperature range of 60oC to 100oC. Nyquist plots were drawn and bulk resistances were obtained. Subsequently, conductivity values were calculated and the diffusion characteristics were obtained. From further analysis of the conductivities with temperature, the diffusion of electrons in the material was studied. It was found that the conductivity increased with the increase of temperature which meant that the rate of diffusion of the electrons through the materials also increased. An Arrhenius relation was concluded for the electron diffusion in the ZnO nanomaterials.