An efficient multi-doping strategy to enhance Li-ion conductivity in the garnet-An efficient multi-doping strategy to enhance Li-ion conductivity in the garnettype solid electrolyte Li7La3Zr2O12 type solid electrolyte Li7La3Zr2O12 Abstract Abstract Lithium-ion (Li + ) batteries suffer from problems caused by the chemical instability of their organic electrolytes. Solid-state electrolytes that exhibit high ionic conductivities and are stable to lithium metal are potential replacements for flammable organic electrolytes. Garnet-type Li 7 La 3 Zr 2 O 12 is a promising solid-state electrolyte for next-generation solid-state Li batteries. In this study, we prepared mono-, dual-, and ternary-doped lithium (Li) garnets by doping tantalum (Ta), tantalum-barium (Ta-Ba), and tantalum-barium-gallium (Ta-Ba-Ga) ions, along with an undoped Li 7 La 3 Zr 2 O 12 (LLZO) cubic garnet electrolyte, using a conventional solid-state reaction method. The effect of multi-ion doping on the Li + dynamics in the garnet-type LLZO was studied by combining joint Rietveld refinement against X-ray diffraction and high-resolution neutron powder diffraction analyses with the results of Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and multinuclear magic angle spinning nuclear magnetic resonance. Our results revealed that Li + occupancy in the tetrahedrally coordinated site (24d) increased with increased multi-ion doping in LLZO, whereas Li + occupancy in the octahedrally coordinated site (96h) remained constant. Among the investigated compounds, the ternary-doped garnet structure Li 6.65 Ga 0.05 La 2.95 Ba 0.05 Zr 1.75 Ta 0.25 O 12 (LGLBZTO) exhibited the highest total ionic conductivity of 0.72 and 1.24 mS cm -1 at room temperature and 60 °C, respectively. Overall, our findings revealed that the dense microstructure and increased Li + occupancy in the tetrahedral-24d Li1 site played a key role in achieving the maximum room-temperature Li-ion conductivity in the ternary-doped LGLBZTO garnet, and that the prepared ternary-doped LGLBZTO was a potential solid electrolyte for Li-ion batteries without polymer adhesion. Disciplines DisciplinesEngineering | Physical Sciences and Mathematics ABSTRACT Lithium-ion (Li + ) batteries suffer from problems caused by the chemical instability of their organic electrolyte. Solid-state electrolytes that exhibit high ionic conductivities and stable to lithium metal are potential replacements for flammable organic electrolytes.Garnet-type Li7La3Zr2O12 is a promising solid-state electrolyte for next-generation solidstate Li batteries. In this study, we prepared mono-, dual-, and ternary-doped lithium (Li)

Li metal, which has a high theoretical capacity and negative electrochemical potential, is regarded as the "holy grail" in Li-ion batteries. However, the flammable nature of liquid electrolyte leads to safety issues. Hence, the cooperation of solid-state electrolyte and Li-metal anode is demanded. However, the short cycle life induced by interfacial issues is the main challenge faced by their cooperation. In this review, dendrite and interfacial side reactions are comprehensively analyzed as the main interfacial problems. Meanwhile, the "state-of-the-art" interphase materials are summarized. The challenges faced by each kind of material are underscored. Moreover, different processing routes to fabricate artificial interphase are also investigated from an engineering perspective. The processing routes suitable for mass production are also underscored.

Solid-state lithium-ion batteries are promising candidates for energy storage devices that meet the requirements to reduce CO2 emissions. NASICON-type solid-state electrolytes (SSE) are most promising materials as electrolytes for high-performance lithium ion batteries because of their good stability and high ionic conductivity. In this study, we successfully fabricate NASICON-based Li1.5Al0.5Ge1.5(PO4)3 lithium fast-ion conductors through melt-quenching with post-crystallization. The effect of crystallization temperature on the structure of LAGP and their ionic conductivity is systematically studied using Rietveld analysis of Synchrotron X-ray powder diffraction patterns, multinuclear magnetic resonance, and electrochemical analysis, revealing that the mobility of Li ion is dependent on crystallization temperature. The glass–ceramic LAGP annealed at 800 °C for 8 h exhibits the highest conductivity of 0.5 mS cm–1 at room temperature. Moreover, we report the viability of the prepared LAGP glass−ceramic as a solid electrolyte in Li-ion batteries without polymer adhesion. The cycling of Li/LAGP/LFP all-solid-state cell, provides a stable cycling lifetime of up to 50 cycles. This approach demonstrates that LAGP glass–ceramic can have good contact with the electrodes without interfacial layer and can deliver a reasonable discharge capacity after 50 cycles.