Sintering behavior of garnet‐type Li6.4La3Zr1.4Ta0.6O12 in Li2CO3 atmosphere and its electrochemical property

Chen

ACS Appl. Mater. Interfaces

et al. 2020

Self Cite

The application of Li-ion conducting garnet electrolytes is challenged by their large interfacial resistance with the metallic lithium anode and the relative small critical current density at which the lithium dendrites short-circuit the battery. Both of these challenges are closely related to the morphology and the structure of the garnet membranes. Here, we prepared four polycrystalline garnet Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) pellets with different particle sizes (nano/micro) and grain boundary additive (with/without Al 2 O 3 ) to investigate the influence of grain size, the composition of the grain boundary, and the mechanical strength of the pellet on the total Li-ion conduction of the pellet, Li/garnet interfacial transfer, and lithium dendrite growth in all-solid-state Limetal cells. The results showed that the garnet pellets prepared with nanoparticles and LiAlO 2 -related grain boundary phase had decreased total Li-ion conductivity because of the increased resistance of the grain boundary; however, these pellets showed higher mechanical strength and improved capability to suppress lithium dendrite growth at high current densities. By controlling the grain size and optimizing the grain boundary with Al 2 O 3 sintering additive, the hot-pressing sintered LLZTO solid electrolytes can reach up to 1.01 × 10 −3 S cm −1 in Li + conductivity and 0.29 eV in activation energy. LLZTO with nanosized grain and LiAlO 2 -modified grain boundary showed the highest critical current density, which is 0.6 mA cm −2 at room temperature and 1.7 mA cm −2 at 60 °C. This study offers a useful guideline for preparing a high-performance LLZTO solid electrolyte.

Section: Resultsmentioning

confidence: 99%

Enhanced Performance of Li_6.4La₃Zr_1.4Ta_0.6O₁₂ Solid Electrolyte by the Regulation of Grain and Grain Boundary Phases

Chen

ACS Appl. Mater. Interfaces

et al. 2020

Self Cite

“…The cubic garnet LLZO was discovered by Murugan et al [17] in 2007 and attracted world-wide attention for its advantages, e.g., the simple preparation process, high ionic conductivity (~10 −3 S•cm −1 ) at room temperature, high electrochemical window (0~6 V vs. Li/Li + ), and electrochemical stability of lithium metal. On the other hand, LLZO also has some defects, such as an unstable cubic phase and a low density of ceramics [20,21]. Moreover, a mass of LLZO mother powder is needed to compensate for lithium loss when sintering at high temperatures [21,22].…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, LLZO also has some defects, such as an unstable cubic phase and a low density of ceramics [20,21]. Moreover, a mass of LLZO mother powder is needed to compensate for lithium loss when sintering at high temperatures [21,22]. Many solutions have been adopted to solve the above issues.…”

Section: Introductionmentioning

confidence: 99%

Submicron-Sized Nb-Doped Lithium Garnet for High Ionic Conductivity Solid Electrolyte and Performance of Quasi-Solid-State Lithium Battery

et al. 2020

The garnet Li7La3Zr2O12 (LLZO) has been widely investigated because of its high conductivity, wide electrochemical window, and chemical stability with regards to lithium metal. However, the usual preparation process of LLZO requires high-temperature sintering for a long time and a lot of mother powder to compensate for lithium evaporation. In this study submicron Li6.6La3Zr1.6Nb0.4O12 (LLZNO) powder―which has a stable cubic phase and high sintering activity―was prepared using the conventional solid-state reaction and the attrition milling process, and Li stoichiometric LLZNO ceramics were obtained by sintering this powder―which is difficult to control under high sintering temperatures and when sintered for a long time―at a relatively low temperature or for a short amount of time. The particle-size distribution, phase structure, microstructure, distribution of elements, total ionic conductivity, relative density, and activation energy of the submicron LLZNO powder and the LLZNO ceramics were tested and analyzed using laser diffraction particle-size analyzer (LD), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Electrochemical Impedance Spectroscopy (EIS), and the Archimedean method. The total ionic conductivity of samples sintered at 1200 °C for 30 min was 5.09 × 10−4 S·cm−1, the activation energy was 0.311 eV, and the relative density was 87.3%. When the samples were sintered at 1150 °C for 60 min the total ionic conductivity was 3.49 × 10−4 S·cm−1, the activation energy was 0.316 eV, and the relative density was 90.4%. At the same time, quasi-solid-state batteries were assembled with LiMn2O4 as the positive electrode and submicron LLZNO powder as the solid-state electrolyte. After 50 cycles, the discharge specific capacity was 105.5 mAh/g and the columbic efficiency was above 95%.

“…Specifically, 47 raw images were collected and annotated into 3 three classes: low (12), median (16), and high (19) according to their measured ionic conductivities (Figure S11 and Table S1). Each raw image was partitioned into a set of image patches (24), each of which was then fed into the DCNN for classification (Figure 3a). By design, each image patch has a size of 340 × 340 pixels (Table S2), and two neighboring patches have an overlap of 170 pixels.…”

Section: Nano Letters Pubsacsorg/nanolettmentioning

confidence: 99%

Machine Learning on Microstructure–Property Relationship of Lithium-Ion Conducting Oxide Solid Electrolytes

Zhang,

Lin,

Zhai

et al. 2024

Nano Lett.

Understanding the structure−property relationship of lithium-ion conducting solid oxide electrolytes is essential to accelerate their development and commercialization. However, the structural complexity of nonideal materials increases the difficulty of study. Here, we develop an algorithmic framework to understand the effect of microstructure on the properties by linking the microscopic morphology images to their ionic conductivities. We adopt garnet and perovskite polycrystalline oxides as examples and quantify the microscopic morphologies via extracting determined physical parameters from the images. It directly visualizes the effect of physical parameters on their corresponding ionic conductivities. As a result, we can determine the microstructural features of a Li-ion conductor with high ionic conductivity, which can guide the synthesis of highly conductive solid electrolytes. Our work provides a novel approach to understanding the microstructure−property relationship for solid-state ionic materials, showing the potential to extend to other structural/functional ceramics with various physical properties in other fields.