Achmad Subhan

Effect of nano silicon content in half-cell Li-ion batteries performance with Li4Ti5O12 xerogel TiO2 solid-state anode materials

Lithium titanate (Li4Ti5O12)/LTO is a promising anode to produce Lithium Ion Battery with high power. In addition, silicon has a theoretical capacity of 3590 mAh g−1 to phase Li15Si4 at room temperature. But lacked by the large volume expansion during cycling and shorten the cycle life of the battery, SEI layer instability due to a material change Si, and low electrical conductivity. However, nano particles of Si has higher specific capacity and storage capacity are better when compared with Si particles that has a micro size. In this research Li4Ti5O12 and nano silicon has a good synergy in the capacity of battery as a composite. This research was synthesized by using solid state methods. XRD and TEM was performed to identify the phase, morphology of LTO powder. Effect of solid-state route and ball mill at Li4T5O12 powder produced has an average particle size of 225.95 nm and the degree of crystallinity of 67%. Cyclic voltammetry (CV), Electro-impedance spectroscopy (EIS), and charge discharge (CD) test ...

Effect of Acetylene Black Content to Half Cells Li-ion Battery Performance Based on Li4Ti5O12 using Li2CO3 as Lithium Ion Source with Hydrothermal Mechanochemical Process

Lithium titanate (Li4Ti5O12)/LTO is a promising candidate to be used as anode electrode in Li-ion battery, to replace graphite in Li-ion battery application. Crystal structure of lithium titanate/LTO is more stable or undergoes less strain than graphite during intercalation and de-intercalation process Li+ ions. However, although lithium titanate has good stability, the material has low electrical conductivity and lithium ion diffusion. The purpose of this research is to synthesis the spinel LTO using combinated hydrothermal and mechanochemical processes from xerogel TiO2. Then, to increase the conductivity, in the half-cell battery assembly process it was added acetylene black conductive (AB) additive with various from 10%, to 15% in wt. The LTO obtained were characterized using scanning electron microscope (SEM), X-Ray Diffraction (XRD) and Brunauer–Emmett–Teller (BET). The XRD showed a rutile as minor phase, while SEM showed homogeneous distribution of particle with an average particle size of 0.35 μm. The BET showed that the surface area of LTO formed is 2.26 m2/g. The assembled coin half cells used this Li4Ti5O12 as a cathode and lithium metal foil as the anode were tested using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and charge discharge (CD). The conductivity value obtained from EIS corresponds to the contents of AB. Meanwhile, the CV and CD testing showed that higher percentage of AB causing the decrease of battery specific capacity. The highest specific capacity at the rate of 10C is obtained at the mixture of 10wt% AB with the value of 40.91 mAh/g.

AC-MnO2-CNT Composites for Electrodes of Electrochemical Supercapacitors

Electrodes for electrochemical supercapacitors were fabricated by doctor blade method of composite of activated carbon (AC), MnO2 and carbon nanotubes (CNTs). The AC-MnO2-CNTs composites were synthesized by solution processing method with pH variation of 3, 7 and 11. The composites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and impedance spectroscopy. The XRD pattern shown the crystalline structure and the SEM image observed that the distribution of CNTs was homogeneous between carbon particles. The electrodes were fabricated for supercapacitor cells with 316L stainless steel as current collector and 1 M Na2SO4 as electrolyte. An electrochemical characterization was performed by using an electrochemical impedance spectroscopy (EIS) method using a LCR Hi-Tester HIOKI 3522 instrument and the results showed an increase in the value of specific capacitance at the AC-MnO2-CNT on the acid reaction condition.

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

Preparation and Characterization of Biomass-Derived Advanced Carbon Materials for Lithium-Ion Battery Applications

In this study, carbon-based advanced materials for lithium-ion battery applications were prepared by using soybean waste-based biomass material, through a straightforward process of heat treatment followed by chemical modification processes. Various types of carbon-based advanced materials were developed. Physicochemical characteristics and electrochemical performance of the resultant materials were characterized systematically. Scanning electron microscopy observation revealed that the activated carbon and graphene exhibits wrinkles structures and porous morphology. Electrochemical impedance spectroscopy (EIS) revealed that both activated carbon and graphene-based material exhibited a good conductivity. For instance, the graphene-based material exhibited equivalent series resistance value of 25.9 Ω as measured by EIS. The graphene-based material also exhibited good reversibility and cyclic performance. Eventually, it would be anticipated that the utilization of soybean waste-based biomass material, which is conforming to the principles of green materials, could revolutionize the development of advanced material for high-performance energy storage applications, especially for lithium-ion batteries application.

Optimizing the performance of Li4Ti5O12/LTO by addition of silicon microparticle in half cell litium-ion battery anode

The demand of lithium-ion battery (LIB) has been increased for high power application in transportation system. Thus, the current use of graphite as anode material needs to be replaced, due to formation of unwanted solid-electrolyte interphase (SEI) layer consuming intercalated Li+ that reduces the LIB performance and may cause ignition of the battery in high load usage. One of the candidates for anode material to replace graphite is lithium titanate (LTO), since the LTO does not form SEI and exhibits high-power with outstanding safety properties. This LTO compound was synthesized by mixing the TiO2 xerogel of anatase phase and lithium carbonate (Li2CO3) as a source of lithium-ion followed by sintering at temperatures of 750°C to obtain the LTO with spinel crystalline phase. However, the LTO has the low theoretical capacity, i.e: 175 mAh/g, with real specific capacity obtained is at 114 mAh/g. To increase the LTO specific capacity, the addition of 10, 20 and 30 wt.% silicon microparticle which has theoretical capacity of 4200 mAh/g was conducted during preparation of the slurry anode mixture to minimize the formation of SiO2. Anode sheet was made with Si/LTO and assembled into half-cell coin battery with lithium metal sheet as the counter electrode. Electro-impedance spectroscopy (EIS), Cyclic voltammetry (CV), and charge discharge (CD) testing were conducted to examine the battery performance. From EIS testing, the lowest impedance was obtained for the sample of 20 wt.% Si, while the highest impedance value obtained in 30 wt.% Si. The CV testing shows that the highest capacity at 141.1 mAh/g is achieved at the composition of 10 wt.% Si. Finally, from the CD testing, this Si/LTO anode could withstand the charge-discharge until 12 C and shows good stability until 100 cycles. From EIS and CV testing known that the optimum composition having the best performance is ranging from 10 wt.% to 20 wt.% Si. It is predicted that at higher composition, the pulverization of Si particle is occurred declining the performance of Si/LTO anode.

Use of carbon pyrolyzed from rice husk in LiFePO4/V/C composite and its performance for lithium ion battery cathode

The characteristics of activated carbon pyrolyzed from rice husk used in the synthesis of LiFePO4/V/C for the development of lithium ion battery cathode has been examined. The synthesis was begun by synthesizing LiFePO4 (LFP) via hydrothermal route using the precursors in stoichiometric amounts of LiOH, NH4H2PO4, and FeSO4.7H2O. The assynthesized LFP was then added with variation of vanadium concentrations and a fix concentration of the carbon pyrolyzed from rice husk to form a composite of LiFePO4/V/C. The composites were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), and electrochemical impedance spectroscopy (EIS). The XRD results showed that the LiFePO4/V/C has been successfully formed whereas SEM results showed a difference in morphology of vanadium and activated carbon addition. The EIS results showed that the conductivity of LiFePO4/C-0 wt.% V is 1.0196×10-2 S/cm, LiFePO4/C-3 wt.% V is 1.0302×10-2 S/cm, LiFePO4/C-5 wt.% V is 6.1282×10-3 S/cm, and LiFePO4/C-7 wt.% V is 8.3843×10-3 S/cm. The best performance for lithium ion battery cathode was given by LiFePO4/V/C at 3 wt.% vanadium. This result indicated that rice husk can be used as a cheap resource for activated carbon in the development of lithium ion battery cathode.

Electrochemical performance of Fe3O4 micro flower as anode for lithium ion batteries

Graphite is generally employed in commercial lithium ion batteries which has a specific capacity of 372 mAh/g. In this study, graphite is replaced with carbon-coated magnetite (Fe3O4/C) which has large theoretical specific capacity of 926 mAh/g, environmental friendly, and low cost production. The synthesis of Fe3O4/C is carried out by hydrothermal method with reacting FeCl3 and hexamethylenetetramine (HMT) at temperature variation of 160, 170 and 180°C. The following process is heated by calcination at temperature variations 450, 500 and 550°C. XRD and SEM results show that the as-prepared Fe3O4/C powder has a single phase of Fe3O4 and morphology micro-flowers like with size between 700 nm – 3 µm. CV test results show redox reaction occurs in the voltage range between 0.21-0.85 V and 1.68-1.81 V. The highest specific discharge capacity is obtained 644 mAh/g for specimen with temperature hydrothermal of 170°C and temperature calcination of 550°C. This result shows that Fe3O4/C has a high potential as anode material for lithium ion battery.Graphite is generally employed in commercial lithium ion batteries which has a specific capacity of 372 mAh/g. In this study, graphite is replaced with carbon-coated magnetite (Fe3O4/C) which has large theoretical specific capacity of 926 mAh/g, environmental friendly, and low cost production. The synthesis of Fe3O4/C is carried out by hydrothermal method with reacting FeCl3 and hexamethylenetetramine (HMT) at temperature variation of 160, 170 and 180°C. The following process is heated by calcination at temperature variations 450, 500 and 550°C. XRD and SEM results show that the as-prepared Fe3O4/C powder has a single phase of Fe3O4 and morphology micro-flowers like with size between 700 nm – 3 µm. CV test results show redox reaction occurs in the voltage range between 0.21-0.85 V and 1.68-1.81 V. The highest specific discharge capacity is obtained 644 mAh/g for specimen with temperature hydrothermal of 170°C and temperature calcination of 550°C. This result shows that Fe3O4/C has a high potential as anod...

STUDI SIFAT ELEKTROKIMIA SEL BATERAI SEKUNDER POUCHCELL LITHIUM ION LIFEPO4/GRAPHITE APLIKASI DAYA TINGGI

In this work, have been fabricated cathode electrode from LiFePO4 powder and anode from commercial Graphite powder. Full cell batteries fabricated in Pouchcell shaped test samples. Lithium ion cell configuration are LiFePO4 // LiPF6 // graphite, 1 M LiPF6 in EC/DEC is used as the liquid electrolyte. Cell batteries Perfomance characterized by some tests conducted on the cyclic voltrametry, charge-discharge and EIS (electrochemical impedance spectroscopy. The result value are the capacity reached approximately 80 mAh / g, with the voltage Voc perfectly stable at 3.28 V. The discharged capacity can be taken up to 5C almost over 40% , with after 50 cycles for life cycle test the capacity loss is retain still 95% at 0.33C.

Optimizing the performance of Li4Ti5O12 anode synthesized from TiO2 xerogel and LiOH with hydrothermal-ball mill method by using acetylene black

Optimizing the Li-ion Batteries performance using Li4Ti5O12 (LTO) as anode material by addition of using Acetylene Black was studied in this research. The LTO was successfully synthesized using sol-gel method to form TiO2 xerogel continued by calcination, hydrothermal, ball milling and sintering process. XRD (X-Ray Diffraction), scanning electron microscopy-Energy Dispersive Spectroscopy (SEM-EDS) and Brunauer–Emmett–Teller (BET) was performed to identify the characteristic of Li4Ti5O12 powder likes phase, morphology, chemical composition and surface area. Spinel Li4Ti5O12 and rutile TiO2 were detected in XRD patterns. The morphology of Li4Ti5O12 shows presence of agglomerates structure. The surface area of Li4Ti5O12 powder is 6.404 m2/g. Electrode sheet then be prepared with LTO and mixed with PVDF binder (5 wt%) and AB 5 wt% (LTO-1), 10 wt% PVDF binder and 10wt% AB (LTO-2), 15 wt% PVDF binder and 15 wt% AB (LTO-3) of total weight solid content. Half-cell coin battery was made with lithium counter electr...