Synthesis and characterization of substituted garnet and perovskite-based lithium-ion conducting solid electrolytes
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Titanium, tantalum-substituted Li7La3Zr2-xAxO12 (LLZO, A = Ta, Ti) garnets, and chromium-substituted La(2/3)-xLi3xTi1-yCryO3 (LLTO) perovskites were prepared by a conventional solid-state reaction and the Pechini processes. The desired crystal phases were obtained by varying the calcination temperature and time, as well as the substitution concentration. All samples indicated decomposition of the precursors when heated above 750 °C and formation of the desired phase after heat treatment at higher temperatures. Neutron diffraction data shows the formation of a predominant cubic phase in the case of Ta-LLZO, and monoclinic phase with minor impurity phases for Cr-LLTO. Ionic conductivity for Ti-LLZO (Li7La3Zr1.4Ti0.6O12), Ta-LLZO (Li6.03La3Zr1.533Ta0.46O12), and Cr-LLTO (La(2/3)-xLi3xTi0.9Cr0.1O3) at room temperature were found to be 5.21 × 10−6, 1.01 × 10−6, and 1.2 × 10−4 S cm−1, respectively. The activation energies of the compounds were determined from the Arrhenius plot and were 0.44 eV (Ti0.6-LLZO), 0.54 eV (Ta0.5-LLZO), and 0.20 eV (Cr0.1-LLTO).
KeywordsSolid electrolytes Garnet Perovskite Lithium-ion conduction Solid-state lithium-ion battery
This work was supported by the Vehicle Technology Program (EERE), Oak Ridge Institute for Science and Education (ORISE), and Mickey Leland Energy Fellowship (MLEF) programs. A portion of this research at ORNL’s Spallation Neutron Source was sponsored by the US Department of Energy, Office of Basic Energy Sciences, Scientific User Facilities Division. Support (MPP and YL) for Neutron characterizations and impedance measurements was provided by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences, and Engineering Division.