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"Sintesis Li4Ti5O12 telah banyak diteliti karena merupakan material yang menjanjikan sebagai anoda baterai ion lithium dibandingkan dengan anoda konvensional seperti carbon. Preparasi sampel TiO2 dilakukan melalui proses solgel Rw 3,5. Lithium titanat disintesiss dengan metode solid-state dengan variabel perbedaan kadar LiOH untuk mengetahui pengaruhnya terhadap struktur kristal, sifat elektrokimia lithium titanat yang dihasilkan. Sampel yang disinteis terdiri dari 3 jenis yaitu penambahan massa LiOH secara stokiometri, massa LiOH berlebih 50% dari stokiometri dan 100% berlebih dari stokiometri. Sampel dikarakterisasi menggunakan EDS, BET, XRD, SEM, dan UV-VIS. Hasil penelitian menunjukkan, lithium titanat yang dihasilkan dengan perbandingan kadar LiOH dengan TiO2 secara stokiometri memilki tingkat kecocokan tertinggi, ukuran partikel dan energi celah terkecil dan luas permukaan terbesar bila dibandingkan dengan sampel yang kadar LiOH dibuat berlebih. Pengaruh dari perbedaan kadar LiOH dapat membentuk pengotor TiO2 rutile dan Li2TiO3.

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Synthesis of Li4Ti5O12 has been widely studied as a promising material as an anode of lithium ion batteries compared to conventional anodes like carbon. Preparation sample of TiO2 is done through a process sol-gel Rw 3.5. Lithium titanate synthesized by solid-state method with variable of LiOH ratio to determine the their effects on the crystal structure, electrochemical properties of lithium titanate produced. Samples were synthesized consisting of three types, which are the addition of LiOH in stoichiometric, mass excess LiOH 50% and 100% of the stoichiometric. The samples were characterized using EDS, BET, XRD, SEM, and UV-VIS.

The results showed, lithium titanate synthesized by stoichiometric ratio of LiOH and TiO2 have the highest match rate, lowest particle size and energy gap and largest surface area, compared to samples synthesized excessive levels of LiOH. The effect of mass variation of LiOH can make impurities like TiO2 rutile and Li2TiO3."

"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)."

"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."

"Litium Titanat, Li4Ti5O12 (LTO) adalah kandidat yang menjanjikan sebagai bahan anoda baterai lithium ion. Dalam penelitian ini, Li4Ti5O12 akan disintesis dengan menggunakan metode solid-state dengan menggunakan komersial TiO2 dan komersial litium hidroksida (LiOH). Setelah itu, komersial bubuk nikel dipanaskan pada suhu 600oC selama 4 jam untuk mendapatkan NiO sebagai logam oksida transisi. Penambahan NiO ke LTO kepada semua sampel sebesar 3%. Tiga variasi penambahan lama waktu proses sintering sebesar 4 jam, 8 jam, 10 jam, diberi label sampel LTO/NiO 3% (4 jam), LTO/NiO 3% (8 jam) and LTO/NiO 3% (10 jam). Karakterisasi dilakukan menggunakan XRD dan SEM untuk mengamati efek penambahan NiO pada struktur dan morfologi sampel yang dibuat. Hasil karakterisasi sampel menunjukkan bahwa penambahan NiO 3% memiliki konduktivitas lebih baik. Hasil dari tes Electrochemical Impedance Spectroscopy juga menunjukkan LTO/NiO 3% (4 jam) memiliki konduktivitas terbaik dengan nilai resistansi terkecil

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Lithium titanate, Li4Ti5O12 (LTO) is a promising candidate as lithium ion battery anode material. In this investigation, Li4Ti5O12 was synthesized with solid-state method by using TiO2 with the help of lithium hydroxide (LiOH) and nickel powder as the precursor materials, resulting in LTO. Commercial nickel powder was heated at 600oC for 4 hours to obtain NiO as transition metal oxide. NiO addition to the LTO for all samples is 3% in weight%. Three variations of different sintering holding time for 4 hours, 8 hours and 10 hours labelled as LTO/NiO 3% (4 hours), LTO/NiO 3% (8 hours) and LTO/NiO 3% (10 hours), respectively. The characterizations were made using XRD and SEM testing. These were performed to observe the effect of NiO addition and different holding time on structure and morphology of the resulting samples. The result showed that the addition of NiO will make the samples have better conductivity. According to Electrochemical Impedance Spectroscopy, LTO/NiO 3% (4 hours) also has the best conductivity with the lowest resistivity."

"Litium titanat (Li4Ti5O12) merupakan senyawa yang digunakan sebagai anoda baterai ion litium. Senyawa litium titanat disintesis berdasarkan metode solid state dengan mereaksikan TiO2 xerogel yang dibuat dengan metode sol-gel dan litium oksida (Li2O). Dalam penelitian ini menggunakan tiga variasi penambahan kadar massa litium oksida (Li2O); massa Li2O sesuai stokiometri (0% melebihi stokiometri), 50% massa Li2O melebihi stokiometri dan 100% melebihi nilai stokiometri. Pengaruh dari penambahan kadar massa litium oksida (Li2O) pada struktur, morfologi, dan energi celah pita tersebut diamati. Sampel yang terbentuk diuji dengan menggunakan X-Ray diffraction, scanning electron microscope (SEM) dan UV-Vis spectroscopy. Hasil penelitian menunjukan bahwa dengan penambahan massa Li2O sesuai stokiometri membentuk senyawa Li4Ti5O12 dan pengotor seperti TiO2 rutile dan Li2TiO3 dengan ukuran kristalit 13,7 nm, ukuran diameter partikel 0,540 μm band gap energy 3,864 eV, penambahan massa Li2O 50% melebihi stokiometri membentuk senyawa Li2TiO3 dengan ukuran kristalit 7,2 nm, ukuran diameter partikel 1,062 μm dan band gap energy 3,838 eV dan penambahan 100% massa Li2O melebihi stokiometri membentuk Li2TiO3 dengan ukuran kristalit 12,4 nm, ukuran diameter partikel 1,916 μm dan band gap energy 3,778 eV. Senyawa Li4Ti5O12 terbentuk hanya dengan penambahan Li2O sesuai stokiometri. Untuk mensintesis senyawa Li4Ti5O12 bebas dari pengotor mengunakan metode solid state dapat mengacu pada diagram fasa Li2O-TiO2 (29% mol Li2O-71% mol TiO2).

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Lithium titanate (Li4Ti5O12) is anode material for application in lithium ion battery. Lithium titanate was synthesized by solid-state method using xerogel TiO2 was prepared by sol–gel process and commercial lithium oxide (Li2O) powder. This research uses 3 various content of lithium oxide (Li2O); 0% Li2O mass excess, 50% Li2O mass excess, and 100% Li2O mass excess. The effect of adding lithium oxide (Li2O) on structure, morphology of particle surface, and band gap energy was examined. Samples were obtained by X-ray diffraction, scanning electron microscope (SEM), ultraviolet visible (UV-Vis).

The results show with adding lithium oxide stoichiometry (0% Li2O excess) produces Li4Ti5O12 and impurities such as rutile TiO2 and Li2TiO3, it produces Li2TiO3 with 50% Li2O excess and it produces Li2TiO3 with 100% Li2O excess. In this research show with appropriate of stochiometry content (0% Li2O excess) produces Li4Ti5O12 with crystallite size is 13,7 nm and impurities namely Li2TiO3 with crystallite size is 22,8 nm and TiO2 with crystallite size 9,14 nm, diameter particle size is 0,540 μm and bandgap energy 3,864 eV. 50% Li2O excess produces Li2TiO3 with crystallite size 7,2 nm, diameter particle size is 1,062 μm and bandgap energy 3,838 eV and with 100% Li2O excess produces Li2TiO3 with crystallite size 12,4 nm, diameter particle size is 1,916 μm and band gap energy is 3,778 eV. The Li4Ti5O12 compound was formed only with appropriate of stoichiometry content. In order to make high purity of Li4Ti5O12 compound on solid state reaction, Li2O-TiO2 phase diagram (29% mol Li2O-71% mol TiO2) can be used as reference."

"Litium Titanat (Li4Ti5O12) memiliki beberapa kelebihan : sifat zero strain, charge-discharge yang panjang, tidak menimbulkan SEI (Solid Electrolyte Interphase). Namun Litium Titanat (LTO) memiliki kapasitas yang rendah (10-9 S cmn-1), dimana diatasi melalui pembuatan komposit dengan material lain. Grafit memiliki kapasitas spesifik yang besar, 372 mAh/g. Penambahan ZnO dapat meningkatkan kapasitas dan konduktivitas. Penelitian ini berfokus mengetahui pengaruh penambahan ZnO variasi 3%, 5%, dan 7% dengan konsentrasi grafit tetap sebesar 5% sintesis solid state dengan sampel pembanding neat LTO dan LTO/Grafit disertai penambahan serbuk LiOH sebesar 6%. XRD menunjukkan adanya Li4Ti5O12 yang terbentuk, dengan ukuran kristalit terbesar pada LTO/Grafit-ZnO 3%. Hasil EIS menunjukkan LTO/Grafit-ZnO 5% memiliki konduktivitas terbaik. Hasil CV menunjukkan Eo terbesar pada 3%, dan uji CV menghasilkan kapasitas spesifik yang lebih besar dari pengujian CD akibat C rate yang lebih besar, dengan kapasitas spesifik tertinggi CV pada LTO/Grafit-ZnO 3%, dan kapasitas terbesar CD pada LTO/Grafit-ZnO 5%, tidak terlalu jauh dengan kapasitas LTO/Grafit-ZnO 3%. Perhitungan retensi menunjukkan LTO/Grafit-ZnO 3% memiliki rate capability baik sehingga tahan lama. Ketiga sampel memiliki efisiensi coulomb tinggi, sehingga tidak ada energi yang hilang selama charge-discharge. Meninjau hasil penelitian, dibutuhkan penelitian lebih lanjut untuk menghasilkan hasil yang optimal dalam meningkatkan konduktivitas serta kapasitas.

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Lithium Titanate (L4Ti5O12) has several advantages, zero strain, good charge-discharge stability, and does not form SEI (Solid Electrolyte Interphase). However, LTO has low specific capacity (10-9 S cmn-1), and to improve that is to make a composite with another materials. Graphite has high specific capacity, 372 mAh/g, and the addition of ZnO would enhanced the capacity and conductivity.

This research focused on examined the effect of ZnO by various concentration 3%, 5% and 7% with a fixed concentration of graphite 5% by using solid state method and make a comparison between the neat LTO along with LTO/Graphite with the addition of excess LiOH 6% for LTO. XRD shows the presence of Li4Ti5O12 on each samples with the biggest crystallite size found in LTO/Graphite-ZnO 3%.

EIS shows LTO/Graphite-ZnO 5% has the best conductivity, and CV shows that LTO/Graphite-ZnO 3% has the biggest specific capacity. CD shows LTO/Graphite-ZnO 5% has the biggest capacity, with a little deviation form LTO/Graphite-ZnO 3%.

Retention indicate the LTO/Graphite-ZnO 3% has good rate capability, and all the samples have good coulumbic efficiency, indicates no energy lost during charge-discharge. Reveiweing the results, further research is need to obtained the best results."

"Fabrikasi anoda lithium titanat (Li4Ti5O12) dengan doping ion Al3+, dan pelapisan karbon melalui metode sol-gel telah berhasil dilakukan. Doping ion Al3+, pelapisan karbon, dan modifikasi permukaan secara sinergik digunakan dalam penelitian ini untuk mengatasi kekurangan Li4Ti5O12. Metode sol-gel pada lingkungan asam merupakan teknik yang sederhana dan mampu menghasilkan material dengan ukuran kecil dan seragam dipandang sebagai cara terbaik untuk dilakukan secara sinergik. Parameter yang diamati dalam penelitian ini antara lain pengaruh pH, jumlah mol doping, pelapisan karbon, dan modifikasi permukaan terhadap struktur kristal, morfologi, dan performa elektrokimia (impedansi, difusi ionik, kapasitas spesifik dan laju kapabilitas). Hasil eksperimen menunjukkan bahwa peningkatan pH secara bertahap dapat meningkatkan fasa pengotor (rutil) dan memicu aglomerasi partikel dan menutup struktur berpori di permukaan. Peningkatan pH juga menurunkan koefisien difusi, nilai kapasitas spesifik dan laju kapabilitas. Doping tidak mempengaruhi fasa, struktur kristal dan morfologi. Doping ion Al3+ cenderung menurunkan kapasitas spesifik pada C-rate rendah (0,1C), namun penambahan ion Al3+ sebanyak 0,03 mol mampu meningkatkan kapabilitas pada laju-C tinggi (5C dan 10 C). Pelapisan karbon pada permukaan Li4Ti5O12 tidak mengubah fasa dan struktur kristal Li4Ti5O12 secara signifikan. Gambar FESEM menunjukkan bahwa karbon Super P melapisi Li4Ti5O12 secara merata sehingga memiliki kapasitas spesifik terbaik. Super P memiliki sifat ringan, berpori dan lebih murni sehingga sampel memiliki kapasitas 249 mAh/g. Sedangkan karbon gula memblokir pori-pori permukaan elektroda dan masih mengandung gugus -OH sehingga memberikan efek negatif pada performa elektrokimia dengan kapasitas spesifik 100 mAh/g. Modifikasi permukaan dengan karbon gula pada Li4Ti5O12 doping Al3+ dengan pirolisis mampu membuat permukaan menjadi kasar, namun modifikasi menurunkan nilai kapasitas spesifik.

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The fabrication of lithium titanate (Li4Ti5O12) with aluminum ion (Al3+) doping and carbon coating using the sol-gel method has been successfully carried out. Al3+ ion doping, carbon coating, and surface modification were used synergistically in this study to overcome the deficiency of Li4Ti5O12. The sol-gel method in an acidic environment is a simple technique and it is capable of producing materials with small size and uniformity which is seen as the best way to perform synergistically. Parameters observed in this study included the effect of pH, number of moles of doping, carbon coating, and surface modification on the crystal structure, morphology, and electrochemical performance (impedance, ionic diffusion, specific capacity, and capability rate). The experimental results show that a gradual increase in pH can increase the impurity phase (rutile) and trigger agglomeration of particles and close the porous structure on the surface. Increasing the pH value also decreases diffusion, specific capacity values and capability. Doping does not affect the phase, crystal structure and morphology. Al3+ ion doping tends to decrease the specific capacity at low C-rate (0.1C), but the addition of 0.03 mol of Al3+ ion can increase the capability at high C-rate (5C and 10C). The carbon layer on the surface of Li4Ti5O12 did not significantly change the facade and crystal structure of Li4Ti5O12. FESEM image shows that Super P carbon coats Li4Ti5O12 evenly so that it has the best specific capacity. Super P is light, porous, and purer so the sample has a capacity of 249 mAh/g. Meanwhile, the sugar carbon blocked the pores of the electrode surface and still contained -OH group so that it had a negative effect on the electrochemical performance with a specific capacity of 100 mAh/g. Surface modification with sugar carbon on Al3+ doped Li4Ti5O12 by pyrolysis make the surface rough, but the modification reduces the value of specific capacity."

"ABSTRAKLitium 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 L240Sn5dengan 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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ABSTRACTLithium 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)."

"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 solidstatedengan bantuan sonikasi menggunakan sumber prekursor TiO2 dan Fe2O3, baikkomersial maupun hasil sintesis. Hasil SEM menunjukkan sampel dengan co-doping Mgdan Fe pada LTO komersial memiliki morfologi yang relatif sama dan seragam dan terjadipengurangan ukuran partikel co-doping LTO dengan x = 0.05. Namun, co-doping LTOhasil sintesis tidak ditemukan adanya reduksi pada ukuran partikel yang mengindikasikanbahwa co-doping Mg dan Fe tidak berpengaruh pada ukuran partikel. Hasil EDSmenunjukkan kehadiran unsur Mg, Fe, Ti, dan O yang menunjukkan bahwa unsur yangdiinginkan pada sampel co-doping dan persebarannya relatif merata. Karakterisasi XRDmenunjukkan bahwa fasa Mg(OH)2 dan Fe2O3 tidak ditemukan di dalam struktur codopingLTO yang mengindikasikan bahwa atom Mg dan Fe telah bergabung denganstruktur LTO. Sampel dengan prekursor TiO2 dan Fe2O3 komersial dan TiO2 sintesisdengan Fe2O3 hasil purifikasi pada komposisi x = 0,1 memiliki fasa pengotor terendahdibandingkan LTO komersial dan LTO sintesis murni yaitu 12,7% dan 9,9%. Nilai Rctsemua sampel co-doping menunjukkan nilai Rct lebih kecil dibandingkan nilai Rct LTOmurni (Rct co-doping < Rct LTO murni). Hal ini menunjukkan bahwa co-doping Mg danFe mengurangi hambatan difusi LTO, sehingga meningkatkan transfer muatan dankonduktivitas listrik. Dengan demikian, menunjukkan bahwa pergerakan ion Li+ lebihmudah pada sampel LTO yang didoping. Sampel LTO sintesis dengan menggunakanprekursor Fe2O3 hasil purifikasi (x = 0,1) memiliki nilai Rct paling rendah dibandingkansemua sampel yaitu 85,41 Ω dan memiliki nilai koefisien difusi ion litium dankonduktivitas 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 danreversibilitas yang paling baik. Pada C-rate tinggi (15C), sampel LTO sintesis denganpenambahan Fe2O3 hasil purifikasi (x=0,1) memiliki kapasitas tertinggi dibandingkansampel co-doping LTO sintesis lainnya yaitu 21,716 mAh/g. Sedangkan pada co-dopingLTO komersial, LTO komersial dengan prekursor Fe2O3 komersial (x=0,1) memilikikapasitas tertinggi yaitu 47,70 mAh/g

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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."

"Litium titanat (Li4Ti5O12) merupakan kandidat yang menjanjikan sebagai anoda baterai Lithium-ion. Litium titanat disintesis menggunakan metode solid state dengan mencampurkan TiO2 xerogel yang dibuat dengan metode sol gel dan litium karbonat (Li2CO3) komersil. Dalam penelitian ini digunakan tiga variasi penambahan kadar massa Li2CO3, yaitu 0% (sampel LTO 1), 50% (sampel LTO 2), dan 100% (sampel LTO 3) melebihi stoikiometri. Karakterisasi menggunakan pengujian XRD, FESEM, UV-vis spectroscopy, dan BET telah dilakukan untuk mengetahui pengaruh kadar litium berlebih terhadap struktur, morfologi, dan energi celah pita sampel. Hasil penelitian menunjukkan bahwa ukuran kristalit, ukuran diameter partikel, energi celah pita, dan luas permukaan masing-masing sampel berturut-turut adalah 8,27 nm, 8,44 μm, 3,88 eV untuk sampel LTO 1; 8,22 nm, 8,56 μm, 4,02 eV, 22,529 m2/gr untuk sampel LTO 2; 4,76 nm, 2,07 μm, 4,12 eV, 16,804 m2/gr untuk sampel LTO 3. Selain itu, litium berlebih yang digunakan dalam sintesis Li4Ti5O12 menyebabkan terbentuknya pengotor TiO2 rutile dan Li2TiO3. Senyawa Li4Ti5O12 hanya terbentuk pada sampel LTO 1 dan LTO 2. Untuk mensintesis senyawa Li4Ti5O12 menggunakan metode solid state tanpa menghasilkan pengotor dapat mengacu pada diagram fasa Li2O-TiO2 (28,64% mol Li2O-71,36% mol TiO2).

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Lithium titanate (Li4Ti5O12) is a promising candidate for lithium ion battery anode. Lithium titanate was synthesized by solid state method using xerogel TiO2 was prepared by sol gel method and commercial lithium carbonate (Li2CO3). This research varies the content of Li2CO3 addition, 0% (sample LTO 1), 50% (sample LTO 2), and 100% (sample LTO 3) Li2CO3 mass excess. Characterization using XRD, FESEM, UV-vis spectroscopy, and BET testing was performed to observe the effect of adding lithium excess in structure, morphology, and band gap energy.

The results show that crystallite size, particle diameter, band gap energy, and surface area of each sample is 8,27 nm, 8,44 μm, 3,88 eV for sample LTO 1; 8,22 nm, 8,56 μm, 4,02 eV, 22,529 m2/gr for sample LTO 2; 4,76 nm, 2,07 μm, 4,12 eV, 16,804 m2/gr for sample LTO 3. Furthermore, the excess of lithium used for Li4Ti5O12 synthesis cause the formation of impurity compound such as rutile TiO2 and Li2TiO3. Li4Ti5O12 compound was successfully syntesized in sample LTO 1 and LTO 2. In order to synthesis pure Li4Ti5O12 without any impurities using solid state method, Li2O-TiO2 phase diagram (28,64% mol Li2O-71,36% mol TiO2) can be used as a reference."