Materials Science Forum Vol. 1000

Abstract: Lithium Titanate (LTO) is one of the anode materials that has good performance because of its unique properties, which is zero-strain. In this study, LTO was synthesized using the sol-gel method and mechanochemical hydrothermal with LiOH as the source of lithium-ion. Silicone oxycarbide (SiOC) is a ceramic material synthesized through a simple pyrolysis process of silicone oil precursors. Carbon used in this study is a carbon activated process so that activated carbon is obtained with a large pore size. The addition of activated carbon to the LTO is done during the sol-gel process, while the addition of SiOC to LTO-C is performed during the slurry making process. SEM-EDS shows the extent of the elements in the sample where Ti, F, Si, O, and C are present. Also, SEM-EDS characterization shows an increase in the amount of carbon in each sample. XRD shows the presence of the LTO spinel phase and impurity phases such as TiO₂ rutile and anatase, and Li₂TiO₃. In EIS performance testing, low resistivity expresses high conductivity. In this research, high conductivity is owned by LTO-1% C/SiOC. In addition, CV and CD performance tests were performed where the highest specific capacity was obtained in the LTO-5%/SiOC samples.

Abstract: Dye-sensitized solar cells (DSSCs) is a part of the third-generation family which have been developed under substantial research for almost three decades due to their low-cost fabrication, low toxicity, and can be manufactured on the flexible substrate. However, the challenge for the improvement of current DSSC is still opened, especially in the scope of efficiency, stability, and platinum (Pt)-free counter electrode. In this work, the incorporation of solution-processed rGO as a replacement for the Pt counter electrode DSSC is demonstrated. The rGO solutions with three different concentrations (1, 3, and 5 wt%) are utilized. The highest power conversion efficiency (PCE) of about 0.1 % is displayed by 5 wt% rGO solution based devices. The results reported in this work exhibited the high potential of solution-processed rGO as an efficient alternative material in the counter electrode of DSSC.

Abstract: Li₄Ti₅O₁₂/Sn was successfully synthesized by a solid-state method using the High Energy Ball Mill Machine as anode for Lithium-Ion batteries. The addition of various (10%, 20%, 30%) Sn-micro particle is aimed to enhance LTO's conductivity and capacity. Characterization of the sample's structure was performed using X-ray diffraction (XRD), which expose the presence of TiO2 rutile and Sn in each sample. The surface area of samples observed using Brunner-Emmet-Teller (BET), which indicates the different surface area of each Sn addition. Scanning electron microscopy (SEM) suggested agglomeration and poor distribution appear in every sample. Cyclic voltammetry (CV) was performed to measure the battery's performance. Two peaks occur as a sign of reversible reaction. The impedance of Li₄Ti₅O₁₂/Sn measured using electrochemical impedance spectroscopy (EIS), the test performed before and after Cyclic voltammetry (CV), each test showed the different result for each sample. Other than EIS and CV, Charge-Discharge (CD) also performed, examinations in different C-rate were performed, and higher Sn concentration leads to lower stability in high C. The result reveals that the addition of 20% Sn optimizes Li₄Ti₅O₁₂ in enhancing capacity and conductivity.

Abstract: To obtain the high specific capacity anode for Lithium-ion battery with stable performance is conducted by synthesizing a composite anode of ZnO-nanorods (ZnO-NR) and as a matrix is the activated carbon (AC). In this study, ZnO-NR synthesized a process that uses basic materials hexamethylenetetramine (HMTA) and zinc oxide. Activated carbon has been activated because it has high porosity and good electrical conductivity properties. Variable used is the percentage of ZnO-NR, which is 30wt%, 40wt%, and 50wt%. Characterization of the samples was examined using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Brunauer–Emmett–Teller (BET). The battery performance of the samples was obtained by Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV), and Charge-Discharge (CD) testing after being assembled into coin cell batteries. This study discusses the effect of adding activated carbon to ZnO NR composites. The results showed that the ZnO-NR30/AC has the highest specific capacity of 270.9 mAh g^-1. According to Brunner-Emmet-Teller (BET) test, the largest surface area was 631.685 m2 g^-1. Electrochemical performance is the best obtained by ZnO-NR30/AC.

Abstract: Synthesis and characterization of LiMn_0.7Fe_0.3PO₄/CNT/C composite used as lithium ion battery cathode has been carried out. The active materials of LiMn_0.7Fe_0.3PO₄ was synthesized via hydrothermal method from the precursors of LiOH, NH₄H₂PO₄, FeSO₄.7H₂O and MnSO₄.7H₂O. The activated carbon was pyrolyzed from coconut shell whereas the carbon nanotube (CNT) was commercially available in the market. The composite was prepared using a ball-mill to mix the components homogeneously. Simultaneous thermal analysis STA was used to determine the formation temperature of LiMn_0.7Fe_0.3PO₄ to which the sintering process was conducted at 700 °C. After sintering, the materials in powder forms were characterized using scanning electron microscope (SEM) to examine the morphology, whereas X-ray diffraction (XRD) was used to identify the phases formed. The performance of the composite as lithium ion battery cathode was characterized using electrochemical impedance spectroscopy (EIS) and battery analyzer. Secondary electron image from SEM showed that the samples have homogeneous particle distribution. Examination result from X-ray diffraction indicated that LiMn_0.7Fe_0.3PO₄ phase has been successfully synthesized with small impurities from a secondary phase. Performance analysis showed that the presence of activated carbon and CNTs in LiMn_0.7Fe_0.3PO₄ to form LiMn_0.7Fe_0.3PO₄/CNTs/C gives significant improvement in the conductivity; however, some more improvement is still needed for the capacity.

Abstract: Lithium-Ion Capacitor (LIC) has shown promising performance to meet the needs of high energy and power-density-energy storage system in the era of electric vehicles nowadays. The development of electrode materials and electrolytes in recent years has improvised LIC performance significantly. One of the active materials of LIC electrodes, activated carbon (AC), can be synthesized from various biomass, one of which is the water hyacinth. Its abundant availability and low utilization make the water hyacinth as a promising activated carbon source. To observe the most optimal physical properties of AC, this study also compares various activation temperatures. In this study, full cell LIC was fabricated using LTO based anode, and water hyacinth derived AC as the cathode. The LIC full cell was further characterized to see the material properties and electrochemical performance. Water hyacinth derived LIC can achieve a specific capacitance of 32.11 F/g, the specific energy of 17.83 Wh/kg, and a specific power of 160.53 W/kg.

Abstract: Lithium-ion capacitors (LIC) is believed to be an ideal option in certain application as energy storage device due to its properties either possessing high energy density (four times higher than electrical double-layer capacitor) or having as much power density as a supercapacitor. In this study, a biomass-based activated carbon (WHAC) was prepared by using the water hyacinth plant through the activation process utilizing a chemical activating agent, KOH. The water hyacinth was carbonized at 500 °C for a 1 h holding time with a ramping temperature of 10 °C/min. Then, the LICs electrode is constructed by two different types of electrode, WHAC as the main active material of cathode and lithium titanate oxide (LTO) for the anode. The biomass-derived activated carbon exhibits a high specific surface area of 791.8 m²/g and a high pore volume of 1.13 m^3/g. The assembled LiCs shows a reasonable electrochemical performance with a maximum specific capacitance of 1.12 F/g with the highest specific energy of 4.48 Wh/kg and specific power of 34.14 W/kg. This LIC cell is one of the promising candidates for future applications due to its low-cost materials and owns more advantages than typical Lithium-ion Batteries (LIBs).

Abstract: Hydroxyapatite (HA) is potentially used as a coating material for titanium alloys to improve their bioactivity and then enhancing the osseointegration characteristic of metal implants for orthopedic application. Electrophoretic Deposition (EPD), one of the coating methods that is widely applied for coating metal because of its simplicity and relatively low cost, is chosen for coating metal implants. HA coating layer quality can be controlled by adjusting applied voltages and coating time of the EPD process. However, the optimum voltage and exposing time has not yet been known for new type titanium implant such as Ti-12Cr and TNTZ. This work is, therefore, focusing on the effect of applied voltage and coating time on the mass growth, HA coating thickness, and surface coverage that can be produced on the surfaces of both alloys, and also on the conventional titanium alloy, Ti6Al4V, for comparison. The result of this work showed that there is a significant influence of the titanium alloy type on the HA layer performances. However, it is necessary to choose a suitable voltage and to expose time for producing a sufficient coating layer that meets the standard of orthopedic implants.

Abstract: Osteosarcoma, as the most frequent bone tumor cases, can be found in the pelvis bone. Within the pelvis, the ilium is the most common location for osteosarcoma, followed by the acetabulum and then the ischium. Surgery of pelvis is difficult and the reconstruction is complicated mainly due to the geometry complexity and also the weight support function of the pelvis. Endoprosthesis of the ilium is therefore designed to increase the quality of life of the patient. In this study, the iliac implant is designed based on the natural geometry of the ilium, and the size is modified to fit the morphometry of the Eastern Asian. A finite element method (FEM) is proposed as a basic study in material selection. Titanium and its alloy (Ti-6Al-4V) are studied as the potential candidate for the proposed implant while the finite analysis of the bone was also included. As a preliminary study, in this FEM, only the static load is given, each material is assumed to be isotropic and the contacts were considered bonded. FEM in this study is expected to give a better understanding of the stress distribution, and to optimize the selection of materials.