A different zirconia precursor for Li7La3Zr2O12 synthesis

Li7La3Zr2O12 (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 ZrO2 as the main precursor. In this research, different-precursors have been used for LLZO synthesis which was a monoclinic ZrO2 powder (m-ZrO2) and tetragonal ZrO2 powder (t-ZrO2). The reaction was conducted at 950 degrees C 6 h and followed by sintering at 1000 degrees C 6 h under Argon gas flow. The result shows that LLZO made from m-ZrO2 (LLZO(A)) and t-ZrO2 (LLZO(B)) contains t-LLZO and c-LLZO which is surprisingly having a similar c/t ratio of 0.124-0.125. The LLZO(A) and LLZO(B) provide a silver blocking ionic conductivity of 1.245 x 10(-6) Scm(-1) and 1.647 x 10(-6) Scm(-1), respectively. In addition, LLZO(B) provides lower specific resistance than LLZO(A) in between LiCoO2 and meso-carbon microbeads (mcmb) electrodes. CV analysis of the symmetrical Li-LLZO(B)-Li cell shows an electrochemical potential of 3.3 V (vs Li/Li+) oxidation and 3.4 V reduction (vs Li/Li+). A time-based Galva-nostatic charge-discharge to Li-LLZO(B)-Li 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 pro-duced from t-ZrO2. The solid-state reaction method provides less expensive production and environmentally friendly by the absence of organic solvent. (C) 2021 The Authors. Published by Elsevier B.V.

Automated summary

The study examines the synthesis of LLZO solid electrolytes using different precursors and finds that LLZO made from m-ZrO2 and t-ZrO2 show similar characteristics and ionic conductivity, with LLZO(B) exhibiting lower resistance and long-term stability. This research highlights the potential for cost-effective and environmentally friendly production of LLZO through the solid-state reaction method.