Hasil Pencarian  ::  Simpan CSV :: Kembali

Abstrak :
Dengan kemajuan teknologi, peningkatan penggunaan penyimpanan energi yang begerak juga semakin bertambah. Salah satu bahan aktif yang digunakan dalam katoda baterai ion litium adalah LiFePO4. Dalam penelitian ini, telah dilakukan sintesis dan proses pemberian doping Na pada material katoda LiFePO4/C menjadi material komposit Li1-xNaxFePO4/C dengan (x = 0, 0,01, 0,02, 0,03, 0,04 dan 0,05) dilakukan dengan kombinasi proses reaksi kimia basah (wet chemical) dan padatan (solid state) pada temperatur kalsinasi 350oC selama 1 jam proses sintering 750oC selama 4 jam. Karakterisasi morfologi, struktur mikro dan komposisi dilakukan dengan menggunakan difraksi sinar-X (XRD) dan mikroskop elektron yang dilengkapi dengan pemindai komposisi (SEM/EDX), sedangkan karakterisasi elektrokimia dalam bentuk sel koin R2032 dilakukan dengan menggunakan voltametri siklik (CV), spektroskopi impedansi elektrokimia (EIS) dan pengisian dan pengosongan (Charge-Discharge). Hasil XRD menunjukkan bahwa semua sampel sesuai dengan LiFePO4/C standar dengan struktur olivine pada kondisi x = 0, sedangkan hasil SEM menunjukan bahwa ukuran partikel semua sampel adalah berkisar antara sekitar 1 sampai dengan 3 µm. Hasil uji CV menunjukkan bahwa doping Na jelas meningkatkan reversibilitas dan perilaku dinamis interkalasi dan deinterkalasi ion lithium. Hasil EIS menunjukkan bahwa doping Na mengurangi resistensi transfer pada material katoda LiFePO4/C dengan meningkatkan koefisien difusi ion lithium. Dapat disimpulkan dari semua karakteriasi material sampel dan sel koin bahwa doping Na dapat meningkatkan kinerja elektrokimia material katoda dengan hasil yang optimal pada x = 0,02 sampai 0,03. ......With the advancement of technology, there is an increase use of mobile energy storage. One of the active materials used in lithium ion battery cathode is LiFePO4. In this work, synthesis and characterization of Li1-xNaxFePO4/C (x = 0, 0.01, 0.02, 0.03, 0.04 dan 0.05) composite has been carried out. The synthesis was performed via combination of wet chemical reaction processes to obtain FePO4 and continued with the process of mixing through solid state reaction method to form Li1-xNaxFePO4/C. In this work, nominal x ratio of sodium to lithium was varied from 0 to 5 wt.%. The calcination was carried out for 1 hour at 350 °C and continued with sintering at 750 °C for 4 hours under nitrogen environment. Morphological characterization and microstructure observation were performed using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD), respectively. The XRD results showed that the obtained active material has uniformity in comparison to the LiFePO4 standard with olivine structure for x = 0. With the addition of sodium, there is an indication that the peak shifted to the lower at the optimum angle. Observation on the morphology showed that the particle size of the obtained active material ranges from about 1 to 3 µm, whereas analysis on the composition showed consistent results. This is as an indication that the synthesis of Li1-xNaxFePO4/C composite has been carried out successfully. The CV test results show that Na doping increases the reversibility and dynamic behavior of lithium ion intercalation and deintercalation. The EIS results show that Na doping reduces transfer resistance in the LiFePO4/C cathode material by increasing the diffusion coefficient of lithium ions. It can be concluded from all the characteristics of the sample material and coin cell that Na doping can improve the electrochemical performance of the cathode material with optimal results at x = 0.02 to 0.03.

Abstrak :
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 ......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.

Abstrak :
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).

---

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.