Synthesis and Raman micro-spectroscopy investigation of Li7La3Zr2O12 (original) (raw)

Towards cubic modification of Li7La3ZR2O12 compound by mechanical milling and annealing of powders

2019

The aim of these studies was to obtain single phase cubic modification of Li7La3Zr2O12 by mechanical milling and annealing of La(OH)3, Li2CO3 and ZrO2 powder mixture. Fritsch P5 planetary ball mill, Rigaku MiniFlex II X-ray diffractometer, Setaram TG-DSC 1500 analyser and FEI Titan 80-300 transmission electron microscope were used for sample preparation and investigations. The applied milling and annealing parameters allowed to obtain the significant contribution of c-Li7La3Zr2O12 in the sample structure, reaching 90%. Thermal measurements revealed more complex reactions requiring further studies.

A different zirconia precursor for Li7La3Zr2O12 synthesis

Journal of Materials Research and Technology, 2021

Li 7 La 3 Zr 2 O 12 (LLZO) is a promising solid electrolyte for all-solid-state lithium-ion batteries. Some studies on LLZO synthesis have been conducted without considering the crystal structure of ZrO 2 as the main precursor. In this research, different-precursors have been used for LLZO synthesis which was a monoclinic ZrO 2 powder (m-ZrO 2) and tetragonal ZrO 2 powder (t-ZrO 2). The reaction was conducted at 950 C 6 h and followed by sintering at 1000 C 6 h under Argon gas flow. The result shows that LLZO made from m-ZrO 2 (LLZO(A)) and t-ZrO 2 (LLZO(B)) contains t-LLZO and c-LLZO which is surprisingly having a similar c/t ratio of 0.124e0.125. The LLZO(A) and LLZO(B) provide a silver blocking ionic conductivity of 1.245 x 10 À6 Scm À1 and 1.647 x 10 À6 Scm À1 , respectively. In addition, LLZO(B) provides lower specific resistance than LLZO(A) in between LiCoO 2 and meso-carbon microbeads (mcmb) electrodes. CV analysis of the symmetrical Li-LLZO(B)eLi cell shows an electrochemical potential of 3.3 V (vs Li/Li þ) oxidation and 3.4 V reduction (vs Li/Li þ). A time-based Galvanostatic chargeedischarge to Li-LLZO(B)eLi shows a capacity drop after the 1st 40 cycles from 0.0383C/cm 2 into 0.0303C/cm 2 during the 2nd 40 cycles, and it remains stable up to 120 cycles. It confirms the long-term electrochemical stability of LLZO(B) which was produced from t-ZrO 2. The solid-state reaction method provides less expensive production and environmentally friendly by the absence of organic solvent.

Addition of Calcined Na2B4O7 on the Synthesis of Li7La3Zr2O12

Jurnal Kimia Sains dan Aplikasi

Li7La3Zr2O12 (LLZO) is a garnet-type electrolyte for all-solid-state lithium-ion batteries (ASSB). It has good chemical and electrochemical stability against lithium and a relatively high ionic conductivity. However, the ionic conductivity needs to be further increased to provide a high specific capacity of the ASSB. Element doping into LLZO is an effort to increase molecular defect, known to enhance the conductivity. This research studied the effect of the Na2B4O7 addition on the LLZO synthesis, producing LLZBO(A). The investigation aims to understand whether the sodium ions dope into the LLZO structure during synthesis, or it is only B ions to enter into the structure. Therefore, another synthesis with B2O3 of B precursor was conducted for comparison (LLZBO(B)). The precursors were mixed stoichiometrically by following the formula of Li7-xLa3-xZr2-xBxNaxO12 (LLZBO, x= 0.15; 0.20; 0.30). XRD analysis equipped with Le Bail refinement found that LLZBO(A) and LLZBO(B) mainly consist o...