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Indriana K.,Gadjah Mada University | Inna Y.K.,Gadjah Mada University | Chotimah,Gadjah Mada University | Salim M.,Center for Science and Technology of Advanced Materials | And 2 more authors.
Materials Science Forum | Year: 2017

The effect of alkaline solvent of NaOH and NH3 in the synthesis of nanostructured titania (TiO2) has been studied. Powder of anatase titania as the precursor was mixed with various volume ratios of 10 M of NaOH and 15 M of NH3. The mixture was heated in Teflon-lined autoclave at 150 °C for 24 h. The as-synthesized TiO2 powders were then washed with 0.1 M HCl and calcined at 300 °C. The calcined samples were characterized using TEM (transmission electron microscope), and XRD (X-Ray diffraction). Raman spectroscopy was further used to determine the contributing crystalline phases for the synthesized TiO2. It is shown that varying the solvent ratios of NOH to NH3 resulted in nanotubes, nanosheets, and nanoparticle morphology of TiO2. The TEM images showed the formation of nanotube structure in alkaline ratio NaOH:NH3 of 1:0 and 3:1, with diameter of about 10 nm. At volume ratio of 1:1, the nanosheets and nanotubes both were formed and at volume ratio of NaOH:NH3 of 1:3, nanosheets contributed as its main morphology. While, at fully NH3 solvent, the nanospheres with anatase domain were produced. Raman spectra confirmed that the major contributor for hydrothermal synthesis employing less NaOH for volume ratio of NaOH:NH3 of 3:1 was predominantly anatase with slight presence of titanate. For volume ratio at higher NH3 the presence of titanate is not prominent, but the morphology has already changed into more nanosheet and then nanospheres. The crystallinity of TiO2 anatase crystalline phase was enhanced as more NH3 utilized. © 2017 Trans Tech Publications, Switzerland.

Jodi H.,Center for Science and Technology of Advanced Materials | Jodi H.,University of Indonesia | Zulfia A.,University of Indonesia | Deswita,University of Indonesia | Kartini E.,Center for Science and Technology of Advanced Materials
International Journal of Technology | Year: 2016

Batteries on the market today still use liquid-type electrolytes, which can result in safety issues caused by electrolyte leakage. Therefore, studies that search for solid-state electrolytes are important for resolving these issues. In this research, a composite of lithium phosphate-montmorillonite-polyvinylidene fluoride (Li3PO4-MMT-PVDF) has been characterized with the aim of detecting the electrochemical performance of Li3PO4 with the addition of MMT. Li3PO4 samples were prepared through a solid-state reaction, which was then mixed with MMT, which had a composition ranging from 5 wt% to 20 wt%, and 1 wt% PVDF as a binder. This characterization was conducted with structural, morphological, and electrochemical aspects. The structural test showed that the X-ray diffraction (XRD) pattern was dominated by Li3PO4 peaks and MMT aluminosilicates. The electrochemical characterization indicated that the conductivity value of the composites was greater than that of Li3PO4. The highest conductivity was achieved with a 15 wt% MMT addition, with a dielectric-constant value of 74.9 at a frequency of 10 kHz. © IJTech 2016.

Gunanto Y.E.,Pelita Harapan University | Adi W.A.,Center for Science and Technology of Advanced Materials | Kurniawan B.,University of Indonesia | Poertadji S.,University of Indonesia | And 3 more authors.
International Journal of Technology | Year: 2017

We have performed resistivity measurements as a function of temperature, with and without an external magnetic field. Magnetization measurements are also done as a function of temperature M(T) as well as a function of an external magnetic field M(H) for La0.73Ca0.27Mn1-xCuxO3 compounds with 0≤x≤0.19. The samples with x = 0 and 0.06 are insulators. As for the samples with x = 0.10, 0.13, and 0.19, they undergo an insulator to metal transition as the temperature is lowered. The insulator-metal transition temperatures are 24 K, 74 K, and 69 K for x = 0.10, 0.13, and 0.19, respectively. The magnetoresistance decreases with increasing values of Cu, i.e. 75%, 72%, 64%, and 35% for x = 0, 0.06, 0.10, and 0.13 respectively. Samples in accordance with the model of crystalline metal Ln R vs. 1/T are compared to Mott insulator models Ln R vs. 1/T0.25. Based on the magnetization curve, a paramagnetic to ferromagnetic transition is observed at Curie temperature, TC, of ~ 196 K, 170 K, 140 K, 137 K, and 113 K for x = 0, 0.06, 0.10, 0.13, and 0.19 respectively. © IJTech 2017.

Syahrial A.Z.,University of Indonesia | Priyono B.,University of Indonesia | Yuwono A.H.,University of Indonesia | Kartini E.,Center for Science and Technology of Advanced Materials | And 2 more authors.
International Journal of Technology | Year: 2016

Lithium titanate, Li4Ti5O12 (LTO) is a promising candidate as lithium ion battery anode material. In this investigation, LTO was synthesized by a solid state method using TiO2 xerogel prepared by the sol-gel method and lithium carbonate (Li2CO3). Three variations of Li2CO3 content addition in mol% or Li2CO3 molar excess were fabricated, i.e., 0, 50 and 100%, labelled as sample LTO-1, LTO-2 and LTO-3, respectively. The characterizations were made using XRD, FESEM, and BET testing. These were performed to observe the effect of lithium excess addition on structure, morphology, and surface area of the resulting samples. Results showed that the crystallite size and surface area of each sample was 50.80 nm, 17.86 m2/gr for LTO-1; 53.14 nm, 22.53 m2/gr for LTO-2; and 38.09 nm, 16.80 m2/gr for LTO-3. Furthermore, lithium excess caused the formation of impure compound Li2TiO3, while a very small amount of rutile TiO2 was found in LTO-1. A near-pure crystalline Li4Ti5O12 compound was successfully synthesized using the present method with stoichiometric composition with 0% excess, indicating very little Li+ loss during the sintering process. © IJTech 2016.

Priyono B.,University of Indonesia | Syahrial A.Z.,University of Indonesia | Yuwono A.H.,University of Indonesia | Kartini E.,Center for Science and Technology of Advanced Materials | And 2 more authors.
International Journal of Technology | Year: 2015

Lithium Titanate (Li4Ti5O12) or (LTO) has a potential as an anode material for a high performance lithium ion battery. In this work, LTO was synthesized by a hydrothermal method using Titanium Dioxide (TiO2) xerogel prepared by a sol-gel method and Lithium Hydroxide (LiOH). The sol-gel process was used to synthesize TiO2 xerogel from a titanium tetra-n-butoxide/Ti(OC4H9)4 precursor. An anatase polymorph was obtained by calcining the TiO2 xerogel at a low temperature, i.e.: 300°C and then the hydrothermal reaction was undertaken with 5M LiOH aqueous solution in a hydrothermal process at 135°C for 15 hours to form Li4Ti5O12. The sintering process was conducted at a temperature range varying from 550°C, 650°C, and 750°C, respectively to determine the optimum characteristics of Li4Ti5O12. The characterization was based on Scanning Thermal Analysis (STA), X-ray Powder Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) testing results. The highest intensity of XRD peaks and FTIR spectra of the LTO were found at the highest sintering temperature (750°C). As a trade-off, however, the obtained LTO/Li4Ti5O12 possesses the smallest BET surface area (< 0.001 m2/g) with the highest crystallite size (56.45 nm).

Jahja A.K.,Center for Science and Technology of Advanced Materials | Panitra M.,Center for Science and Technology of Advanced Materials | Honggowiranto W.,Center for Science and Technology of Advanced Materials | Mustofa S.,Center for Science and Technology of Advanced Materials | Yunasfi Y.,Center for Science and Technology of Advanced Materials
Ionics | Year: 2015

Spinel LiMn2O4 has been known to be a technologically important, environmental-friendly, and low-cost cathode material used in Li-based rechargeable batteries, and it is also widely available. Nanoparticle spinel LiMn2O4 has been synthesized by the top-down, high-energy milling, and hydrothermal methods. SEM images, X-ray diffraction patterns, and neutron high-resolution powder diffraction patterns have confirmed the nanocrystalline nature of the spinel LiMn2O4 samples. Raman and Fourier transform infrared (FTIR) measurements show typical absorption and vibration spectra typical for the spinel LiMn2O4 showing the formation of various metallic bonds in the sample. The strongest Raman and FTIR signals come from the higher frequency region, with weaker signals appearing in the lower frequency range. © 2015 Springer-Verlag Berlin Heidelberg

Erizal,Center for Application of Isotopes and Radiation | Abbas B.,Center for Application of Isotopes and Radiation | Sukaryo S.G.,Center for Science and Technology of Advanced Materials | Barleany D.R.,Sultan Ageng Tirtayasa University
Indonesian Journal of Chemistry | Year: 2015

A series of superabsorbent hydrogels were synthesized from partially neutralized acrylic acid with varying degree of neutralization (0-1) using gamma radiation. The effects of degree neutralization of acrylic acid on swelling ratio were studied. DSC measurement was performed to understand the type of end products resulting from irradiation. The morphologies of the hydrogels were examined using SEM. The chemical changes of the hydrogels were characterized using FTIR. At optimum conditions (10 kGy, 15 min), the hydrogels with neutralization degree 0.5 exhibited rapid swelling with the highest swelling ratio ~1000 g/g. The results of DSC studies confirmed the possible formation of the type hydrogels from irradiated partially neutralized acrylic acid, and the hydrogels showed large numbers of pores from SEM examination. © 2015, Gadjah Mada University. All rights reserved.

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