Chairul Hudaya

Phenyl-rich silicone oil as a precursor for SiOC anode materials for long-cycle and high-rate lithium ion batteries

Silicon oxycarbide (SiOC) is gaining increasing attention as a promising anode material for lithium ion batteries due to its higher reversible capacity compared to incumbent graphite. The kinetic processes at a SiOC anode result in rapid capacity fading even at a relatively low current density, thereby hindering its commercialization. Herein, a distinctive, phenyl-rich silicone oil is used as a precursor for producing SiOC anode materials via simple pyrolysis. We find that only silicone oil with phenyl-rich rings can be converted into SiOC materials. The phenyl group was crucial for carbon incorporation to allow Si–O–C bonding and the formation of a free-carbon phase. The resulting SiOC anode exhibited stable cyclability up to 250 cycles, with a discharge capacity of 800 mA h g−1 at a current density of 200 mA g−1. The remarkable cycle performance of SiOC was correlated with its low dimensional expansion (7%) during lithiation, which maintains its structure over cycling. Rate capability tests showed a highly stable performance with a maximum discharge capacity of 852 mA h g−1 at a current density of 100 mA g−1. When the discharge current density was increased 64-fold, the reversible capacity of the SiOC anode was 90% of its maximum capacity, 772 mA h g−1. The excellent electrochemical performance of SiOC could be attributed to the rapid mobility of Li+ within the SiOC matrix, as indicated by a Li+ diffusion coefficient of 5.1 × 10−6 cm2 s−1.

High thermal performance of SnO2:F thin transparent heaters with scattered metal nanodots.

Facile production and novel transparent heaters consisting of fluorine-doped tin oxide (SnO2:F or FTO) thin films covered with three different scattered metal nanodots (Cr-nd, NiCr-nd and Ni-nd) prepared by plasma-enhanced sputtering system and electron cyclotron resonance-metal organic chemical vapor deposition are investigated. The heaters exhibit excellent optical transmittances of over 85% and superior saturated temperatures of more than 80 °C when a relatively low 12 V DC is supplied. The scattered metal nanodots FTO heaters successfully improve the specific power of bare FTO heater by 21, 15, and 12% for NiCr-nd FTO, Cr-nd FTO, and Ni-nd FTO, respectively. These results reveal that the FTO transparent heaters with scattered metal nanodots are the suitable heating materials that can be applied for various functional devices.

Effects of process parameters on sheet resistance uniformity of fluorine-doped tin oxide thin films

An alternative indium-free material for transparent conducting oxides of fluorine-doped tin oxide [FTO] thin films deposited on polyethylene terephthalate [PET] was prepared by electron cyclotron resonance - metal organic chemical vapor deposition [ECR-MOCVD]. One of the essential issues regarding metal oxide film deposition is the sheet resistance uniformity of the film. Variations in process parameters, in this case, working and bubbler pressures of ECR-MOCVD, can lead to a change in resistance uniformity. Both the optical transmittance and electrical resistance uniformity of FTO film-coated PET were investigated. The result shows that sheet resistance uniformity and the transmittance of the film are affected significantly by the changes in bubbler pressure but are less influenced by the working pressure of the ECR-MOCVD system.

Self-Relaxant Superelastic Matrix Derived from C60 Incorporated Sn Nanoparticles for Ultra-High-Performance Li-Ion Batteries

Homogeneously dispersed Sn nanoparticles approximately ⩽10 nm in a polymerized C60 (PC60) matrix, employed as the anode of a Li-ion battery, are prepared using plasma-assisted thermal evaporation coupled by chemical vapor deposition. The self-relaxant superelastic characteristics of the PC60 possess the ability to absorb the stress-strain generated by the Sn nanoparticles and can thus alleviate the problem of their extreme volume changes. Meanwhile, well-dispersed dot-like Sn nanoparticles, which are surrounded by a thin SnO2 layer, have suitable interparticle spacing and multilayer structures for alleviating the aggregation of Sn nanoparticles during repeated cycles. The Ohmic characteristic and the built-in electric field formed in the interparticle junction play important roles in enhancing the diffusion and transport rate of Li ions. SPC-50, a Sn-PC60 anode consisting of 50 wt % Sn and 50 wt % PC60, as confirmed by energy-dispersive X-ray spectroscopy analysis, exhibited the highest electrochemical performance. The resulting SPC-50 anode, in a half-cell configuration, exhibited an excellent capacity retention of 97.18%, even after 5000 cycles at a current density of 1000 mA g-1 with a discharge capacity of 834.25 mAh g-1. In addition, the rate-capability performance of this SPC-50 half-cell exhibited a discharge capacity of 544.33 mAh g-1 at a high current density of 10 000 mA g-1, even after the current density was increased 100-fold. Moreover, a very high discharge capacity of 1040.09 mAh g-1 was achieved with a capacity retention of 98.67% after 50 cycles at a current density of 100 mA g-1. Futhermore, a SPC-50 full-cell containing the LiCoO2 cathode exhibited a discharge capacity of 801.04 mAh g-1 and an areal capacity of 1.57 mAh cm-2 with a capacity retention of 95.27% after 350 cycles at a current density of 1000 mA g-1.

Pilot-scale electron cyclotron resonance-metal organic chemical vapor deposition system for the preparation of large-area fluorine-doped SnO2 thin films

The authors report the surface morphology, optical, electrical, thermal and humidity impacts, and electromagnetic interference properties of fluorine-doped tin oxide (SnO2:F or “FTO”) thin films on a flexible polyethylene terephthalate (PET) substrate fabricated by a pilot-scale electron cyclotron resonance–metal organic chemical vapor deposition (PS ECR-MOCVD). The characteristics of large area FTO thin films were compared with a commercially available transparent conductive electrode made of tin-doped indium oxide (ITO), prepared with an identical film and PET thickness of 125 nm and 188 μm, respectively. The results revealed that the as-prepared FTO thin films exhibited comparable performances with the incumbent ITO films, including a high optical transmittance of 97% (substrate-subtracted), low electrical resistivity of about 5 × 10−3 Ω cm, improved electrical and optical performances due to the external thermal and humidity impact, and an excellent shielding effectiveness of electromagnetic interference of nearly 2.3 dB. These excellent performances of the FTO thin films were strongly attributed to the design of the PS ECR-MOCVD, which enabled a uniform plasma environment resulting from a proper mixture of electromagnetic profiles and microwave power.

The Influence Of Deposition Time And Substrate Temperature Upon Spray Pyrolysis Process On The Resistivity And Optical Trasmittance Of 2 Persenwt Fluorine Doped Tin Oxide (Fto) Glass

Transparent conducting oxide (TCO) glasses play important role in many recent modern technologies including its application for dye sensitized solar cell. One of the most commonly used is indium tin oxide (ITO), however its price is rather expensive. Therefore, the main purpose of the current research is aimed at replacing ITO with fluorine-doped tin oxide (FTO) which is easier and more economic for fabrication. For this purpose, tin chloride dehydrate (SnCl2.2H2O) precursor doped with ammonium fluoride (NH4F) source by using sol-gel method and spray pyrolisis technique can be considered as a new breakthrough in the making of conductive glass. In this work, the ammonium floride was doped at a ratio of 2 wt persen to tin chloride precursor with variations of deposition time (10,20 and 30 minutes) and substrate temperature (250, 300 and 350 °C) upon spray pyrolysis technique. The results showed that the longer deposition time the thicker glass layer is, providing smaller resistivity. In this study, the highest transmittance of 75.5 persen and the lowest resistivity of 3,32 x 10-5 Ω.cm resitivitas were obtained from the glass subjected to 20 minutes deposition time and 300 oC substrate heating during the process. International Journal of Technology (2016) 8: 1335-1343

Concept development for quantification of integrated energy security

Energy security is one of the important factors for energy policy of the country. However, there are many concepts offered by the researchers on energy security, leading to such a diverse and complicated interpretation. Here we develop a novel concept which elaborates the global perspectives. It is realized through a deep evaluation on energy security evolution, followed by a philosophical study of the subject matter and sight of view of energy security, resulting in an integrated energy security theory. The concept is applied to quantify energy security of Indonesia. The operational concept is a set of measurement instruments consisting of 7 dimensions, 31 indicators and 97 sub-components using dynamic programming algorithm. The result of this study provides an approximated number reflecting the aggregate index of energy security.