Anne Zulfia Syahrial

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 Aging on Characterization of Sr-Modified Stir Cast A356/Al2O3 Composite

A356/Al2O3 composites with Sr modifier were produced by stir casting process. The composites were further heat treated to obtain light material with superior characteristics through precipitation hardening of Mg2Si precipitate. The A356 alloy is reinforced with 10 %Vf Al2O3 micro particles. Small amount of Sr is added to modify eutectic silicon morphology from plate-like into fibrous. The composites were prepared by stir casting method in order to obtain dispersed reinforcement particulates within the matrix. T6 heat treatment is employed to the fabricated composites for 2, 4, 6, 8, and 10 hours of aging time to improve the properties. The result reveals that an optimum values of tensile strength, impact strength, hardness and wear rate are achieved by conducting 6 hours of aging. Longer than that, the properties will decline as a result of incoherent phase domination. Small amount of Sr is shown to be able to change the morphology of eutectic silicon from plate-like into fibrous. However, Fe-intermetallics formation, porosity, and negative effect from solution treatment due to improper technical condition during heat treatment are found to contribute on deterioration of mechanical properties of the material.

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.

Effect of Sr addition on the microstructure and mechanical properties of ADC12/nano Al2O3 composites produced by stir casting method

The effects of Sr addition on microstructure and mechanical properties of ADC12/nano Al2O3 composite has been studied. In this research ADC12 as a matrix was added by 0.3 vf% nano Al2O3 as a reinforcement and Al-5Sr varied from 0.00 wt% to 0.05 wt% to modify the eutectic structure of the matrix. The composites were further characterized both microstructural analysis and mechanical properties. The results showed that the intermetallic phases including β-Al5FeSi and Al2Cu were detected using scanning electron microscope and α-Al(Mn,Fe)Si or α-cubic phases was possible to form due to high content of Mn in the composites. The Mg2Si primary, binary, and ternary phases were detected in this composites by metallographic examination. Then, MgAl2O4 (spinnel) were found by XRD analysis. The higher of Sr content from 0,00 to 0.02 the lower SDAS formation from 15 µm to 14 µm as well as porosity content reduced from 4% to 3%. The ultimate tensile strength increased from 115 MPa to 137 MPa as well as in impact toughness from 0.016 J/mm2 to 0.025 J/mm2. The highest hardness and the lowest wear rate were obtained with the addition of 0.05 wt% Sr with 46 HRB and 1.04 10−5 mm3/m respectively due to the changed of chinese script became refined fibrous type.The effects of Sr addition on microstructure and mechanical properties of ADC12/nano Al2O3 composite has been studied. In this research ADC12 as a matrix was added by 0.3 vf% nano Al2O3 as a reinforcement and Al-5Sr varied from 0.00 wt% to 0.05 wt% to modify the eutectic structure of the matrix. The composites were further characterized both microstructural analysis and mechanical properties. The results showed that the intermetallic phases including β-Al5FeSi and Al2Cu were detected using scanning electron microscope and α-Al(Mn,Fe)Si or α-cubic phases was possible to form due to high content of Mn in the composites. The Mg2Si primary, binary, and ternary phases were detected in this composites by metallographic examination. Then, MgAl2O4 (spinnel) were found by XRD analysis. The higher of Sr content from 0,00 to 0.02 the lower SDAS formation from 15 µm to 14 µm as well as porosity content reduced from 4% to 3%. The ultimate tensile strength increased from 115 MPa to 137 MPa as well as in impact toughnes...

SINTESIS LITHIUM TITANAT DENGAN METODE HIDROTERMAL DAN EFEK SUHU SINTERING PADA KARAKTERISTIK NANO STRUKTURNYA

SINTESIS LITHIUM TITANAT DENGAN METODE HIDROTERMAL DAN EFEK SUHU SINTERING PADA KARAKTERISTIK NANO STRUKTURNYA. Lithium titanat merupakan salah satu senyawa yang digunakan sebagai material anoda pada baterai lithium ion. Senyawa ini disintesis dengan mencampurkan TiO 2 anatase dan lithium karbonat (Li 2 CO 3 ) dan diproses menggunakan metode hidrotermal pada suhu 120 o C selama 15 jam, selanjutnya disinter pada tiga variasi suhu sintering yaitu 550 o C, 650 o C dan 750 o C untuk menghasilkan LTO fasa spinel kristalin. TiO 2 anatase yang dipakai dibuat dengan metode sol-gel dengan suhu kalsinasi 300 o C selama 2 jam. Senyawa yang dihasilkan diamati dengan menggunakan X-Ray Diffraction (XRD), Brunauer Emmet Teller (BET), Spektroskopi Infra Merah (FT-IR) dan Field Emission Scanning Electron Microscope (FE-SEM). Hasil foto mikrograf FE-SEM memperlihatkan padatan senyawa lithium titanat (Li 4 Ti 5 O 12 ), Li2TiO3, dan sisa TiO 2 rutile dengan struktur morfologi tidak beraturan sebagai aglomerat. Hasil XRD dan BET menunjukkan bahwa pada suhu sintering 550 o C dihasilkan ukuran kristalit ratarata 23,45 nm, luas permukaan 6,65 m2/g, dan didominasi oleh TiO 2 rutile, sementara suhu sintering 650 o C dihasilkan ukuran kristalit rata-rata 27,70 nm, luas permukaan 1,91m2/g, dan masih didominasi oleh TiO 2 rutile dan pada suhu 750 o C dihasilkan ukuran kristalit rata-rata 52,06 nm, luas permukaan sangat kecil, dan didominasi oleh litihum titanat (Li 4 Ti 5 O 12 ). Hasil FT-IR mengkonfirmasikan keberadaan LTO spinel pada padatan hasil sintering. Ukuran kristalit yang diperoleh dalam kisaran di bawah 100 nm, sesuai dengan tujuan penelitian ini.

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.

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...

Effect of Acetylene Black Content in Li4Ti5O12 Xerogel Solid-State Anode Materials on Half-Cell Li-ion Batteries Performance

The effect of Acetylene Black (AB) additive contents in lithium titanate/Li4Ti5O12 (LTO) anode on Li-ion Batteries performance is studied in this work. The LTO active material for Li-ion batteries anode was successfully synthesized using sol-gel method to form TiO2 xerogel continued by mixing process with LiOH in ball-mill and then sintered to obtain spinel LTO. The LTO powder is characterized by X-Ray Diffraction (XRD), scanning electron microscopy-Energy Dispersive Spectroscopy (SEM-EDS), and Brunauer–Emmett–Teller (BET). The spinel LTO and TiO2 rutile were detected by XRD diffractogram. The LTO powder is in the form of agglomerates structure. This powder then was mixed with PVDF binder (10%wt) and AB additives with various amount from 10%wt (LTO2 Ac-1), 12%wt (LTO2 Ac-2), and 15%wt (LTO2 Ac-3) of total weight solid content to form electrode sheet. Half-cell coin battery was made with lithium metal foil as a counter electrode. Cyclic voltammetry (CV), Electrochemical-impedance spectroscopy (EIS), and charge discharge (CD) test used to examine the battery performance. The highest resistance value is obtained in LTO2 Ac-3 sample with 15%wt of AB. It might be caused by the formation of side reaction product on electrode surface at initial cycle due to high reactivity of LTO2 Ac-3 electrode. The highest initial capacity at CV test and CD test was obtained in LTO2 Ac-1 (10%wt AB) sample, due to the best proportion of active material content in the compound. While, in the charge-discharge test at high current rate, the best sample rate-capability performance belongs to LTO2 Ac-3 sample (15%wt AB), which still have 24.12 mAh/g of discharge capacity at 10 C with 71.34% capacity loss.