Sahrul Hidayat

Synthesis of LiFePO4/Pani/C composite as a cathode material for lithium ion battery

In recent years, LiFePO4 studied intensively as a cathode material for Li-ion batteries because of high theoretical capacity, stability, and environmental friendly. However, its low intrinsic electronic conductivity. One way to improve its conductivity is addition of conductive material. Polyaniline (PANI) is one of the conductive polymer materials that widely studied because its unique physical and chemical properties which can be an insulator and conductor by doping-dedoping processes and has large potential application. The purpose of this research is to improve the conductivity of LiFePO4 with conductive polymer PANI. The method is performed by the addition of LiFePO4 during the polymerization process to form LiFePO4 polyaniline then added to the C-PANI with the addition of mass percent variation of 5%, 10%, 15%, 20% form-LiFePO4 composite PANI-C. In LiFePO4 added during polymerization PANI provide a smooth surface profile after composited with the carbon to LiFePO4-PANI-C compared to LiFePO4-C. LiFeP...

Synthesis and characterization of CMC from water hyacinth for lithium-ion battery applications

Recently, the most dominating power supply on the mobile electronics market are rechargeable Lithium-ion batteries. This is because of a higher energy density and longer lifetime compared to similar rechargeable battery systems. One of the components that determine the performance of a lithium ion battery is the binder material, whether at the anode or the cathode. In commercial batteries, the material used as the binder is Polyvinylidene Difluoride (PVDF), with n-methyl-2-phyrrolidone (NMP) as the solvent. Both are synthetic materials that are expensive, toxic and harmful to the environment. An alternative binder material for lithium-ion battery electrodes is CMC (carboxymethyl cellulose) in a water solvent. CMC is cheaper than PVDF, non-toxic and more environmental friendly. CMC can be synthesized from several types of plants, such as water hyacinth, which is a weed plant with high cellulose content. The synthesis of CMC consists of three main steps, namely 1) the isolation process from water hyacinth, 2) the alkalization and carboxymethylation process and 3) the purification process to obtain CMC in high purity. FTIR characterization of the CMC shows five region of absorption bands. The bands in the region 1330-1400 cm−1 are due to symmetrical deformations of CH2 and OH groups. The ether bonds in CMC occur in the fingerprint region of 1250-1060 cm−1. The presence of new and strong absorption band around 1600 cm−1 is confirmed to the stretching vibration of the carboxyl group (COO−), while the one around 1415 cm−1 is assigned to carboxyl groups as it salts. The broad absorption band above 3400 cm−1 is due to the stretching frequency of the hydroxyl group (-OH). Purity test on three samples (CMC mesh-100, CMC mesh-60 and CMC, mesh-40) gives purity values of 99.89%, 99.99% and 99.89%, respectively. This proves that CMC have actually been formed with high purity.Recently, the most dominating power supply on the mobile electronics market are rechargeable Lithium-ion batteries. This is because of a higher energy density and longer lifetime compared to similar rechargeable battery systems. One of the components that determine the performance of a lithium ion battery is the binder material, whether at the anode or the cathode. In commercial batteries, the material used as the binder is Polyvinylidene Difluoride (PVDF), with n-methyl-2-phyrrolidone (NMP) as the solvent. Both are synthetic materials that are expensive, toxic and harmful to the environment. An alternative binder material for lithium-ion battery electrodes is CMC (carboxymethyl cellulose) in a water solvent. CMC is cheaper than PVDF, non-toxic and more environmental friendly. CMC can be synthesized from several types of plants, such as water hyacinth, which is a weed plant with high cellulose content. The synthesis of CMC consists of three main steps, namely 1) the isolation process from water hyacinth, ...

PENGUJIAN PENGARUH LUAS ELEKTRODA TERHADAP KARAKTERISTIK BATERAI LiFePO4

Baterai lithium-ion telah digunakan sebagai media penyimpan energi listrik portabel karena memiliki densitas energi tinggi dan siklus hidup yang panjang. Bahan yang umum digunakan sebagai katoda pada baterai lithium-ion adalah lithium cobalt oxide (LiCoO 2 ), tetapi unsur kobalt merupakan logam berat yang berbahaya bagi lingkungan, memiliki harga yang mahal dan bersifat reaktif sehingga mudah terjadi ledakan pada temperatur tinggi. Saat ini telah dikembangkan baterai lithium-ion dari lithium iron phospate (LiFePO 4 ) sebagai bahan pada katoda yang lebih murah, aman serta ramah lingkungan. Secara teori, luas elektroda mempengaruhi kapasitas baterai. Semakin luas elektroda, semakin besar kapasitas baterai. Pada penelitian ini telah dibuat baterai lithium-ion dengan LiFePO 4 sebagai bahan pada katoda serta telah dilakukan pengujian baterai dengan melihat pengaruh luas elektroda terhadap karakteristik kinerja baterai dengan metode charge-discharge. Berdasarkan pengujian yang telah dilakukan, baterai dengan luas elektroda (22 x 2) cm 2 dan arus pembebanan 3 mA memiliki kapasitas dan efisiensi paling besar dibandingkan luas elektroda lainnya dengan kapasitas baterai sebesar 3,183 mAh dan efisiensi sebesar 46,6%. Hasil yang didapat menunjukkan luas elektroda dapat mempengaruhi kapasitas dan efisiensi baterai.

Self-Assembly of ZnO-Nanorods and Its Performance in Quasi Solid Dye Sensitized Solar Cells

Zinc oxide (ZnO) nanorods (NRs) were successfully prepared by self-assembly methods using zinc nitrate hexahydrate and hexamethylenetetramine as raw materials. ZnO-NRs were grown on FTO/ZnO seed layer and to enhance dye adsorption it was continued by deposition of titania (TiO2) paste by screen printing method. Deposition time of ZnO-NRs were varied, for 120, 150 and 180 minutes and subsequently stacked with one layer of TiO2 mesoporous. The resulting heterojunction layers of FTO/ZnO-Nrs/TiO2 was then applied as a photoanode in quasi-solid dye sensitized solar cell (QS- DSSC) with polymer gel electrolyte (PGE) as a hole conductor. UV-Vis spectrometer was used to investigate the changes of dye adsorption in photoanode with/without inserting titania mesoporous. Characterizations of scanning electron microscopy (SEM) and X-ray diffraction was carried out and the results shows that increasing the deposition time produces a smaller average grain size, diameter and denser layer of ZnO-nanorods. From current-voltage measurement, higher efficiency (η = 2.53%) was obtained for 120 min ZnO nanorods with short circuit current density (Jsc ) of 2.84 mA/cm2 and open circuit voltage (Voc) of 0.7 V. The combination of TiO2 and ZnO-NRs shows a better performance in solar cells characteristics due to increases of dye adsorption on photoanode and high photogenerated electron transport rate. This work emphasizes an optimum condition of ZnO-NRs in combination with TiO2 mesoporous as an alternative photoanode in QS-DSSC.

Modification of Blue LED using Organic-Inorganic Hybrid Polymer Doped with Nile Red for Artificial Lighting of Photosynthesis

The photosynthesis process of chlorophyll absorbs only the light with wavelength in the blue and red ranges. The absorption peak of the chlorophyll-A is at 428 nm and 660 nm, while absorption peak of chlorophyll-B is at 453 nm and 643 nm. We report the modification of blue LED using hybrid polymer doped with Nile Red. In order to match the total absorption spectra of chlorophyll-A and chlorophyll-B, the emission spectrum of the modified blue LED was taken out by using the wavelength conversion material. We modified the blue LED by covering the blue LED of 450 nm as excitation source with precursor of red wavelength conversion material. The red wavelength conversion material was prepared by doped precursor of TMSPMA hybrid polymer with organic phosphor of Nile Red. The precursor of hybrid polymer was synthesized using sol-gel process and then it was doped with 0.1% Nile Red. In order to freeze the precursor of these conversion material, we employed UV photopolymerization process. The modified blue LED has two emission peaks, which are at 448 nm (blue emission) and at 651 nm (red emission). The optimum spectrum profile of the modified blue LED has similar range as the total absorption spectra of chlorophyll-A and chlorophyll-B that obtain using Nile Red with the mass of 2.9 μg and the driven current of 60 mA. This result has a potential application for the artificial lighting in the photosynthesis process of horticultures at indoor plantation.

ALAT PENDETEKSI dan PENGUKUR KADAR RHODAMIN B SEBAGAI PEWARNA BERBAHAYA PADA MAKANAN dengan BASIS LED RGB

Abstrak Rhodamin B adalah salah satu zat pewarna sintetis yang biasa digunakan pada industri tekstil dan kertas. Zat tersebut ditetapkan sebagai zat yang dilarang penggunaannya pada makanan melalui Menteri Kesehatan (Permenkes) No.239/Menkes/Per/V/85. Namun penggunaan Rhodamin B dalam makanan masih banyak dilakukan oleh masyarakat. Rhodamin B memiliki senyawa pengalkilasi (CH 3 -CH 3 ) yang bersifat radikal sehingga dapat berikatan dengan protein, lemak, dan DNA dalam tubuh. Konsumsi Rhodamin B dalam jangka panjang dapat terakumulasi di dalam tubuh dan dapat menyebabkan gejala pembesaran hati dan ginjal, gangguan fungsi hati, kerusakan hati, gangguan fisiologis tubuh, dan dapat memicu timbulnya kanker hati. Pada penelitian ini telah dilakukan pembuatan alat pendeteksi Rhodamin B yang fleksibel dan mudah dioperasikan dengan basis LED RGB. Berdasarkan hasil eksperimen, senyawa Rhodamin B sangat sensintif terhadap berkas cahaya hijau. Berkas cahaya pada panjang gelombang tersebut mengalami serapan yang cukup tinggi dan berbanding lurus terhadap besarnya kadar Rhodamin B. Alat yang dirancang telah dapat menunjukkan kemampuan untuk membedakan senyawa yang mengandung pewarna Rhodamin B atau tidak. Selain itu alat tersebut juga mampu menghitung perkiraan kadar Rhodamin B dalam satuan mol/liter. Persamaan konversi perubahan tegangan sensor dengan konsentrasi Rhodamin B adalah: konsentrasi (mg/mL) = (tegangan sensor (mV) – 120,98) / (-1,967). Kata-kata kunci: Rhodamin B, LED RGB, pewarna sintetik. Abstract Rhodamine B is a synthetic dye used in the textile and paper industries. These substances are defined as prohibited substances in food through the Minister of Health 239/Menkes/Per/V/85. However, the Rhodamine B is commonly used in the foods by some people. Rhodamine B has an alkylating compounds (CH 3 -CH 3 ) that are radially with binding proteins, fats and DNA in the body. Consumption of Rhodamine B in the long term can accumulate in the body and cause symptoms of an enlarged liver or kidney, impaired liver function, liver damage, physiological disorders of the body, and lead to liver cancer. In this research has been carried out the manufacture of the detector Rhodamine B which flexible and easy to operate on the basis of the RGB LEDs. Based on our experimental results, the Rhodamine B is very sensintif with the green light beam. Beam of light at these wavelengths is absorp by Rhodamin B which proportional to its concentration. Our equipment is designed to demonstrate the ability of distinguish between containing dye Rhodamine B or not. In addition, the equipment is able to calculate the concentration of Rhodamine B in mol / liter. The conversion equation of voltage to concentration of Rhodamine B is: concentration (mg/mL) = (voltage-sensor (mV) – 120,98) / (- 1,967). Keywords : Rhodamin B, RGB LED, synthetic dye .

DESAIN LVDT SEBAGAI TRANSDUCER PENGUKUR TEBAL FILM TIPIS

Linier Variable Deference Transformer (LVDT) adalah salah satu transducer yang dapat digunakan untuk pengukuran tebal profil film tipis menggunakan metode Stylus-Elektromekanis. Untuk menerapkan metoda tersebut diperlukan suatu instrumentasi yang terdiri dari perangkat keras dan perangkat lunak. Perangkat keras akan mengolah fluktuasi sinyal analog akibat gerak stylus diatas sampel film tipis yang dikopel pada ferit sebagai inti transducer LVDT, kemudian mengubahnya menjadi sinyal digital. Selanjutnya sinyal digital ini direkam ke dalam komputer melalui fasilitas akusisi data. Perangkat keras dirancang berdasarkan domain waktu. Perangkat lunak dirancang untuk melakukan akusisi data, mengolahnya, berikut intepretasi kuantitatifnya. Oleh karenanya sistem instrumentasi pengukur tebal profil film tipis ini dibuat dilengkapi pula dengan berbagai submenu yang diperlukan, sehingga seluruh proses mulai dari akusisi data sampai dengan intepretasinya dapat dilakukan secara bersamaan. Sensitivitas dari pengukuran bergantung dari parameter geometri tarnsducer LVDT yaitu, panjang dan luas penampang kumparan, jumlah lilitan, karakteristik osilator eksitasi dan stylus. Dalam riset ini, didesain untuk sensitifitas optimalnya 2,5mV/1,5 m m. Alternatif untuk meningkatkan sensitivitas yaitu merubah panjang kumparan menjadi 1-mm, dengan ini akan didapat sensitivitas optimal 2,5 mV/0,5 m m. Cara ini masih terus diuji coba .

Effect of polyaniline to enhance lithium iron phosphate conductivity

Lithium cobalt oxide is commonly used as secondary battery. One of the disadvantages of lithium cobalt oxide is highly toxicity waste. One of the promising cathode is lithium iron phosphate (LiFePO4). But it has poor conductivity (10-9 S/cm), so conductive material must be added to improve its conductivity. The present paper aims to study the effect of Polyaniline (PANI) and PVDF to enhance lithium iron phosphate conductivity. PANI was prepared through interfacial polymerization. Hydrochloric acid, ammonium persulfate, and toluene were used as dopant, oxidant, and organic solvent respectively. Their morphology was confirmed by scanning electron microscopy (SEM), molecular structure was investigated by Infrared Spectroscopy, and conductivity was confirmed by four point probes method. The composite products have conductivities in the range 9.14 × 10-3 – 6.2×10-1 S/cm. This result is expected to provide an alternative conductive material that can improve the conductivity of lithium iron phosphate, as well as...

Conduction Properties of PTMSPMA-PEO and its Application as Polymer Electrolyte in LiFePO4 Batteries

The conduction properties of polymer composite PTMSPMA-PEO as electrolyte in lithium-ion batteries has been investigated. The gel polymer of PTMSPMA was synthesized by sol-gel method using 3-(Trimethoxysilyl)-propyl-methacrylate as monomer. The Composite of PTMSPMA-PEO with various composition (50:50, 60:40, 80:20; wt%) was made by solution method. The polymer electrolyte was composed of LiClO4 salt dissolved in propylene carbonate and mixed with PTMSPMA-PEO. The ionic conduction of polymer electrolyte was characterized by electrochemical impedance spectroscopy. The battery performance of polymer electrolyte was estimated with coin cell, where LiFePO4 was used as cathode and graphite was use as anode. The high ionic conductivity of 6.67 x10-3 S/cm has been observed for the composition of PTMSPMA : PEO 60:40 (wt%) in room temperature. The performance of cell battery was investigated by charge-discharge using constant current 0,1 mA/cm2. The operational voltage of cell battery is around 1 V until 2.2 Volt with Columbic efficiency around 60%.

Fabrication of Photonic Crystal Based on Polystyrene Particles

Photonic crystals are dielectric materials with different refractive index or permittivity periodically. Photonic crystals have widely application for future technology such as waveguide, optical transistor, cavity of laser and biosensor. Photonic crystals can be fabricated in three types i.e 1D, 2D and 3D structure. In this paper, we report the successful fabrication of 3D photonic crystal from polystyrene particles. The fabrication process began with the synthesis of polystyrene particles followed by deposition on glass and flexible substrate using self-assembly method. We obtained polystyrene monodispered particles which have a uniform shaped with diameter 320 nm. Self-assembly method resulted to the arrangement of polystyrene particles on glass and flexible substrate. Stop band which is related to its optical property are at wavelength of 721 nm and 631 nm for photonic crystal on glass and flexible substrate, respectively. We found that filling fraction of photonic crystal on flexible substrate is lower than that of glass substrate due to some defects.