Iman Rahayu

LSO apatite-YSZ composite as a solid electrolyte for solid oxide fuel cells

LSO (Lanthanun Silicate Oxide) Apatite-YSZ (Yttria-stabilized zirconia) composite has been synthesized by combining the LSO apatite with commercial YSZ with different composition ratio (LSO Apatite:YSZ = 60:40wt.% and 50:50 wt. %). Structure, morphology, and conductivity of sintered pellets composite (sintered at 1330oC for 3 hours) were characterized by XRD, SEM, and impedance spectroscopy, respectively. The sintered density of the composite materials with 50:50 wt. % and 60:40 wt. % (apatite: YSZ) ratios were 3.785 g.cm−3 and 3.770 g.cm−3, respectively. The typical peak of LSO and YSZ were observed in the X-ray pattern of the composite materials. The conductivity of the LSO apatite : YSZ composite 50:50wt. % and 60:40 wt. % ratios showed high level of ionic conductivities with values of 1.26 × 10−3 S/cm and 1.60 × 10−4 S/cm, respectively,with very low level of activation energy (0.95–1.02 eV) at 700 °C. These results indicate that the LSO-YSZ composite materials are good conductors that can be used as s...

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, ...

Synthesis of gadolinium doped titanium(IV) oxide and their photocatalytic activity to decrease chemical oxygen demand (COD) value of water pollutants

Pesticides are widely used for the control of plant disease. Unfortunately they are highly toxic to terraneous and aquatic life; this is a particular problem in agricultural areas. TiO2 is widely used for pesticide control because of its photocatalytic activity, but it still has inadequacy in its wide band gap. Alternatively, the wide band gap of TiO2 could be narrowed by modification with rare earth element such as gadolinium, so the photocatalytic activity of TiO2could be significantly enhanced. The purpose of this experiment is to synthesize Gd/TiO2 and its application to reduce COD of water pollutants such as carbosulfan pesticide. This experiment is done by doping gadolinium oxide into titanium tetra isopropoxide by sol-gel method. The crystal structure is characterized by using XRD, shown anatase successfully obtained with the smallest crystallite size is 37.655 nm, indicated optimum calcination time is 4 hours. SEM-EDX result shown morphology of crystal is big aggregates. Photocatalytic activity is tested to carbosulfan pesticide, obtained the COD percent decreases up to 87.88%.Pesticides are widely used for the control of plant disease. Unfortunately they are highly toxic to terraneous and aquatic life; this is a particular problem in agricultural areas. TiO2 is widely used for pesticide control because of its photocatalytic activity, but it still has inadequacy in its wide band gap. Alternatively, the wide band gap of TiO2 could be narrowed by modification with rare earth element such as gadolinium, so the photocatalytic activity of TiO2could be significantly enhanced. The purpose of this experiment is to synthesize Gd/TiO2 and its application to reduce COD of water pollutants such as carbosulfan pesticide. This experiment is done by doping gadolinium oxide into titanium tetra isopropoxide by sol-gel method. The crystal structure is characterized by using XRD, shown anatase successfully obtained with the smallest crystallite size is 37.655 nm, indicated optimum calcination time is 4 hours. SEM-EDX result shown morphology of crystal is big aggregates. Photocatalytic activity is...

Synthesisofc-lifepo4 composite by solid state reaction method

In this research, the enhancement of LiFePO4 conductivity was conducted by doping method with carbon materials. Carbon-based materials were obtained from the mixture of sucrose, and the precursor of LiH2PO4 and α-Fe2O3 was synthesized by solid state reaction. Sintering temperature was varied at 700°C, 800°C, 900°C and 1,000°C. The result showed that C-LiFePO4 could be synthesized by using solid state reaction method. Based on the XRD and FTIR spectrums, C-LiFePO4 can be identified as the type of crystal, characterized by the appearance of sharp signal on (011), (211) and typical peak of LiFePO4 materials. The result of conductivity measurement from C-LiFePO4 at sintering temperature of 900°C and 1,000°C was 2×10-4 S/cm and 4×10-4S/cm, respectively. The conductivity value at sintering temperature of 700°C and 800°C was very small (<10-6 S/cm), which cannot be measured by the existing equipment.

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%.