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Abstrak :
ABSTRAK
Litium titanat (Li4Ti5O12)/LTO merupakan senyawa yang digunakan sebagai anoda baterai litium ion. Untuk meningkatkan performa baterai litium ion maka dilakukan material komposit pada LTO yaitu LTO nanorod/Sn-grafit. Penelitian ini membahas pengaruh variasi temperatur hidrotermal pada Li4Ti5O12 nanorod dan variasi persen berat timah (Sn) pada Li4Ti5O12 nanorod/Sn -grafit sebagai anoda baterai litium. Variasi temperatur hidrotermal pada sintesis LTO nanorod adalah 2000 C, 2200 C, dan 2400 C. Variasi komposisi persen berat Sn adalah 5%, 7,5%,dan 10%. Sementara persen berat grafit adalah konstan sebesar 10%. Karakterisasi material dilakukan dengan XRD dan SEM. Analisis performa baterai dilakukan dengan pengujian EIS, CV, dan CD. Hasil pengujian XRD menunjukkkan terdapat senyawa LTO nanorod, TiO2 rutile, Li2TiO3, Sn dan grafit. Hasil pengujian SEM menunjukkan tidak ada aglomerasi yang terbentuk dan semakin tinggi temperatur hidrotermal maka bentuk LTO nanorod semakin jelas. Hasil pengujian EIS menunjukkan penambahan persen berat Sn menurunkan nilai konduktivitas. Nilai konduktivitas berbanding terbalik dengan nilai resistivitas (Rct). Nilai konduktivitas tertinggi pada sampel L240Sn5 dengan nilai Rct 58,04 Ω . Hasil pengujian CD menunjukkan bahwa material Sn pada komposit meningkatkan nilai kapasitas baterai. Tetapi penambahan persen berat Sn akan menurunkan nilai kapasitas baterai secara drastis seperti terlihat di nilai C-rates sampel. Hasil pengujian CV menunjukkan nilai kapasitas yang paling tinggi adalah 179,38 Mah/g yaitu pada sampel L220Sn7,5. Nilai sampel paling rendah adalah 130,02 Mah/g pada sampel L200Sn7,5. Tegangan kerja yang paling baik adalah 1,5585 V pada sampel L240Sn5. Tegangan kerja pada sampel ini mendekati tegangan kerja nominal LTO yaitu 1,55V. Variasi Sn pada komposit LTO nanorod/Sn-grafit yang paling baik adalah 5 % (L240Sn5-G10).

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ABSTRACT
Lithium titanate (Li4Ti5O12) / LTO is a compound used as an anode for lithium ion batteries. To improve the performance of lithium ion batteries, composite materials are carried out on LTO, namely LTO nanorod / Sn-graphite. This study discusses the effect of hydrothermal temperature variations on Li4Ti5O12 nanorods and variations in the weight percent of Sn on Li4Ti5O12 nanorod / Sn-graphite as an lithium battery anode. Hydrothermal temperature variations in the synthesis of LTO nanorods are 2000 C, 2200 C, and 2400 C. The variation of the composition of weight percent Sn is 5%, 7.5%, and 10%. While graphite weight percent is constant at 10%. Material characterization is done by using XRD and SEM. The performance analysis of the battery is done by testing the EIS, CV, and CD. The XRD test results showed that there are compounds of LTO nanorod, rutile TiO2, Li2TiO3, Sn and graphite. SEM test results show that no agglomerates are formed and the higher the hydrothermal temperature, the more clear the shape of the LTO nanorod. The EIS test results show that the addition of weight percent Sn decreases the conductivity value. The conductivity value is inversely proportional to the resistivity value (Rct). The highest conductivity value in the L240Sn5 sample with an Rct value of 58.04 Ω. The CD test results show that the Sn material on the composite increases the value of the battery capacity. But the addition of weight percent Sn will reduce the value of battery capacity drastically as seen in the sample C-rates. The CV test results show the highest capacity value is 179.38 Mah / g, ie in the L220Sn7.5 sample. The lowest sample value is 130.02 Mah / g in the L200Sn7.5 sample. The best working voltage is 1.5585 V in the L240Sn5 sample. The working voltage in this sample approaches the nominal working voltage of LTO which is 1.55V. The best variation of Sn in LTO nanorod / Sn-graphite composites is 5% (L240Sn5-G10).

Abstrak :
Anoda Li4Ti5O12 (LTO) yang didoping dengan Mg dan Fe dalam bentuk Li4- xMgxTi5-xFexO12 (x = 0, 0.05, 0.1) telah berhasil disintesis menggunakan metode solidstate dengan bantuan sonikasi menggunakan sumber prekursor TiO2 dan Fe2O3, baik komersial maupun hasil sintesis. Hasil SEM menunjukkan sampel dengan co-doping Mg dan Fe pada LTO komersial memiliki morfologi yang relatif sama dan seragam dan terjadi pengurangan ukuran partikel co-doping LTO dengan x = 0.05. Namun, co-doping LTO hasil sintesis tidak ditemukan adanya reduksi pada ukuran partikel yang mengindikasikan bahwa co-doping Mg dan Fe tidak berpengaruh pada ukuran partikel. Hasil EDS menunjukkan kehadiran unsur Mg, Fe, Ti, dan O yang menunjukkan bahwa unsur yang diinginkan pada sampel co-doping dan persebarannya relatif merata. Karakterisasi XRD menunjukkan bahwa fasa Mg(OH)2 dan Fe2O3 tidak ditemukan di dalam struktur codoping LTO yang mengindikasikan bahwa atom Mg dan Fe telah bergabung dengan struktur LTO. Sampel dengan prekursor TiO2 dan Fe2O3 komersial dan TiO2 sintesis dengan Fe2O3 hasil purifikasi pada komposisi x = 0,1 memiliki fasa pengotor terendah dibandingkan LTO komersial dan LTO sintesis murni yaitu 12,7% dan 9,9%. Nilai Rct semua sampel co-doping menunjukkan nilai Rct lebih kecil dibandingkan nilai Rct LTO murni (Rct co-doping < Rct LTO murni). Hal ini menunjukkan bahwa co-doping Mg dan Fe mengurangi hambatan difusi LTO, sehingga meningkatkan transfer muatan dan konduktivitas listrik. Dengan demikian, menunjukkan bahwa pergerakan ion Li+ lebih mudah pada sampel LTO yang didoping. Sampel LTO sintesis dengan menggunakan prekursor Fe2O3 hasil purifikasi (x = 0,1) memiliki nilai Rct paling rendah dibandingkan semua sampel yaitu 85,41 Ω dan memiliki nilai koefisien difusi ion litium dan konduktivitas paling besar yaitu 2,081 x 10-11 cm2.s-1 dan 2,913 S.cm-1. Selain itu, memiliki nilai ΔE yang paling rendah, sehingga memiliki derajat polarisasi terendah dan reversibilitas yang paling baik. Pada C-rate tinggi (15C), sampel LTO sintesis dengan penambahan Fe2O3 hasil purifikasi (x=0,1) memiliki kapasitas tertinggi dibandingkan sampel co-doping LTO sintesis lainnya yaitu 21,716 mAh/g. Sedangkan pada co-doping LTO komersial, LTO komersial dengan prekursor Fe2O3 komersial (x=0,1) memiliki kapasitas tertinggi yaitu 47,70 mAh/g ......Li4Ti5O12 (LTO) anode doped with Mg and Fe in the form of Li4-xMgxTi5-xFexO12 (x = 0, 0.05, 0.1) was successfully synthesized using the solid-state method with sonication using TiO2 and Fe2O3 precursor sources, both comercial and synthetic. SEM results showed that the co-doped samples of Mg and Fe on commersial LTO had relatively the same and uniform morphology and particle size reduced of the LTO codoped particles with x = 0.05. However, co-doping of synthesized LTO was not found in any reduction in particle size, indicating that Mg and Fe co-doping had no effect on particle size. The EDS results showed the presence of Mg, Fe, Ti, and O elements which indicated that the desired element in the co-doping sample and its distribution was relatively even. XRD characterization showed that Mg(OH)2 and Fe2O3 phases were not found in the LTO co-doping structure indicating that Mg and Fe atoms had joined the LTO structure. Samples with commercial TiO2 dan Fe2O3 precursor and synthesized TiO2 with purified Fe2O3 at the composition x = 0.1 had the lowest impurity phase compared to commersial LTO and synthetic LTO, namely 12.7% and 9.9%. The Rct value of all codoping samples shows that the Rct value is smaller than the Rct value for pure LTO (codoping Rct < pure LTO Rct). This suggests that the co-doping Mg and Fe reduces the diffusion resistance of LTO, thereby increasing charge transfer and electrical conductivity. Thus, it shows that the movement of Li+ ions is easier in the co-doped LTO samples. Synthesized LTO samples using the purified Fe2O3 precursor (x = 0.1) has the lowest Rct value compared to all samples, namely 85.41 Ω and has the greatest value of lithium ion diffusion coefficient and conductivity values of 2.081 x 10-11 cm2.s-1 and 2.913 S.cm-1. In addition, it has the lowest ΔE value, so it has the lowest degree of polarization and the best reversibility. At a high C-rate (15C), the synthetic LTO sampel with the addition of purified Fe2O3 (x = 0.1) has the highest capacity compared to other synthetic LTO co-doping samples, namely, 21.716 mAh/g. While in commersial LTO co-doping, sampel commercial Fe2O3 precurcor (x = 0.1) has the highest capacity of 47.70 mAh/g.

Abstrak :
Lithium titanate, Li4Ti5O12 (LTO) is a promising candidate as lithium ion battery anode material. In this investigation, LTO was synthesized by a solid state method using TiO2 xerogel prepared by the sol-gel method and lithium carbonate (Li2CO3). Three variations of Li2CO3 content addition in mol% or Li2CO3 molar excess were fabricated, i.e., 0, 50 and 100%, labelled as sample LTO-1, LTO-2 and LTO-3, respectively. The characterizations were made using XRD, FESEM, and BET testing. These were performed to observe the effect of lithium excess addition on structure, morphology, and surface area of the resulting samples. Results showed that the crystallite size and surface area of each sample was 50.80 nm, 17.86 m2/gr for LTO-1; 53.14 nm, 22.53 m2/gr for LTO-2; and 38.09 nm, 16.80 m2/gr for LTO-3. Furthermore, lithium excess caused the formation of impure compound Li2TiO3, while a very small amount of rutile TiO2 was found in LTO-1. A near-pure crystalline Li4Ti5O12 compound was successfully synthesized using the present method with stoichiometric composition with 0% excess, indicating very little Li+ loss during the sintering process.

Abstrak :
Lithium Titanate (Li4Ti5O12) or (LTO) has a potential as an anode material for a high performance lithium ion battery. In this work, LTO was synthesized by a hydrothermal method using Titanium Dioxide (TiO2) xerogel prepared by a sol-gel method and Lithium Hydroxide (LiOH). The sol-gel process was used to synthesize TiO2 xerogel from a titanium tetra-n-butoxide/Ti(OC4H9)4 precursor. An anatase polymorph was obtained by calcining the TiO2 xerogel at a low temperature, i.e.: 300oC and then the hydrothermal reaction was undertaken with 5M LiOH aqueous solution in a hydrothermal process at 135oC for 15 hours to form Li4Ti5O12. The sintering process was conducted at a temperature range varying from 550oC, 650oC, and 750oC, respectively to determine the optimum characteristics of Li4Ti5O12. The characterization was based on Scanning Thermal Analysis (STA), X-ray Powder Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) testing results. The highest intensity of XRD peaks and FTIR spectra of the LTO were found at the highest sintering temperature (750oC). As a trade-off, however, the obtained LTO/Li4Ti5O12 possesses the smallest BET surface area (< 0.001 m2/g) with the highest crystallite size (56.45 nm).