TY  - THES
T1  - Preparation and characterization of lithium lanthanum titanate lithium-ion conducting solid electrolyte
A1  - Dono, Andrew C.
A2  - Cervera, Rinlee Butch M.
LA  - English
PP  - Quezon City
PB  - College of Engineering, University of the Philippines Diliman
YR  - 2017
UL  - https://tuklas.up.edu.ph/Record/UP-99796217612562385
AB  - There has been a continually growing imporlance in lithium ionic solid electrolytes in recent years due to their technological applications like in high-energy all solid state lithium ion batteries and properties of high power density and good safety. Lithium lanthamun titanate (LLTO) Li3xLa(2/3)-x D(1/3 )-2xTiO3 was stable at a wide range of composition (0 < x < 0.167). The x≈ 0.1 member exhibits the highest bulk ionic conductivity of 1 x 10-3 S/cm at room temperature. However, the total ionic conductivity is low due to the low grain boundary ionic conductivity in the order of 10-5 to 10-7 S/cm. In this study, the general objective is to synthesize and characterize LLTO with x = 0.167, 0.117, 0.097, 0 indicates vacancy and initially investigate its potential as a lithium-ion conducting solid electrolyte. The experimental procedures carry out in this study consist of three (3) main phases which are as follows: (I) Preparation of the precursor powders; (2) Sintering of LLTO samples through solid state method; and (3) Preparation of sintered samples for electrochemical impedance spectroscopy (ElS) measurement. Thermal behavior of the as-prepared LLTO powders were analyzed using TG-DTA and likewise functional groups of the as-prepared, as-calcined and as-sintered LLTO were examined using FTIR. Sintered LLTO samples were completely characterized for its microstructural properties. Results shows that a pure LLTO phase to all composition were obtained in the form cubic perovskite Pm3m space group as observed from the XRD patterns. Moreover, morphology and compositions of the sintered LLTO samples were examined using SEM-EDS confirmed that the samples achieved high density because few pores were observed. The observed relative densities are above 94% for all samples. Likewise, EDS elemental mapping revealed the presence of La, Ti and O. The ionic conductivity of the sintered LLTO samples were evaluated using electrochemical impedance spectroscopy (EIS) analysis. Temperature dependence were carried out for Li0.50 La0.50 TiO3 1150:36, Li0.35 La0.55 TiO3 1150:36 and Li0.29 La0.57 TiO3 1150:36 since this samples exhibit high  total ionic conductivity (crT) at room temperature. The total ionic conductivity are 1.21 x 10-03, 1.69 x 10-03 and 8.20 x 10-04 S/cm for Li0.50 La0.50 TiO3 1150:36. Li0.35 La0.55 TiO3 1150:36 and Li0.29 La0.57 TiO3 1150:36 respectively at room temperature. The Li0.35 La0.55 TiO3 1150:36 showed high total ionic conductivity compared to the previous reported literatures.
CN  - LG 995 2017 M37 D66
KW  - Lithium cells.
KW  - Electrolytes : Conductivity.
ER  -