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Solid-state electrolyte as a crucial component in all-solid-state batteries should have high Li-ion conductivity and good stability in air. Recently, a new solid Li-ion conductor LiTa2PO8 (LTPO) with theoretical and experimental Li-ion conductivities of 35.3 and 0.25 mS/cm has been reported. Herein, we systematically investigate the ionic conductivity and chemical stability of the LTPO electrolytes sintered by conventional sintering (CS) and hot-pressing sintering (HP) methods. The effects of Li sources, sintering temperature, and the dwelling time are concerned. LTPO pellets using CH3COOLi·2H2O as the Li source sintered by CS method have a room-temperature Li-ion conductivity of 1.86 × 10–4 S/cm with an activation energy of 0.36 eV. A conductivity of 3.12 × 10–4 S/cm with an activation energy of 0.32 eV is achieved by further HP sintering. Moreover, LTPO shows excellent chemical stabilities in air, aqueous solution, and organic solvent and shows a stable cycling performance in the symmetric Li/Li cells and the all-solid-state Li/LiFePO4 batteries with the separation of a thin PEO membrane. [ABSTRACT FROM AUTHOR]

A garnet-type solid-state electrolyte Li6.4La3Zr1.4Ta0.6O12 (LLZTO) was modified using dopamine to improve the wettability of LLZTO with PEO, allowing 80 wt% LLZTO to be uniformly dispersed in 20 wt% PEO/LiTFSI polymer electrolyte. Transmission electron microscopy and Fourier transform infrared spectroscopy confirmed a 4–5 nm thick polydopamine (PDA) layer coating on LLZTO nanoparticles. The composite LLZTO@PDA/PEO electrolyte was synthesized using a solvent casting method. The composite electrolyte has good compatibility and adhesion with both positive and negative electrodes of Li-ion batteries owing to the superior wetting capability of dopamine. This property allows for improved interfacial contact at the electrode/solid electrolyte interface which can decrease the overall resistance of the battery. With dopamine modification, the conductivity of the composite electrolyte at 30 °C increased from 6.3 × 10−5 S cm−1 to 1.1 × 10−4 S cm−1, and the interfacial resistance between the composite electrolyte and a metallic lithium anode decreased from 308 Ω cm2 to 65 Ω cm2 at 50 °C. The composite electrolyte also demonstrated improved thermal stability. [ABSTRACT FROM AUTHOR]

Magnetoplumbite-type LaMgAl11O19 ceramic has been proposed as one of promising candidates for the next generation thermal barrier coatings ( TBCs) due to its low thermal conductivity. However, LaMgAl11O19 shows poor water-resistance with significant weight loss at elevated temperatures in water-containing atmosphere. In this work, we revealed that the essential reason for the poor water-resistance of magnetoplumbite-type LaMgAl11O19 ceramic is Mg2+ migration from the intrinsic site under moisture environment. And then an effective approach was proposed to improve its anti-deliquescent property by completely substituting divalent alkaline earth ions Mg2+ with Zn2+. Finally, a panoscopic strategy was proposed to further lower thermal conductivity through co-substituting La and Zn sites in LaZnAl11O19 with trivalent and divalent transition metal ions. The mechanism for the lowered thermal conductivity is due to the panoscopic approach, which providing all-scale hierarchical architectures of phonon scattering mechanisms. The excellent anti-moisture performance and ultralow thermal conductivity endow the LaZnAl11O19 based ceramics as a kind of promising candidates for advanced thermal barrier coatings. [ABSTRACT FROM AUTHOR]

The garnet-type solid Li-ion conductor, Li6.4La3Zr1.4Ta0.6O12, is viewed as a promising solid-state electrolyte for the next-generation high-performance Li-ion battery because of its high ionic conductivity and stability. The previous researches, in order to avoid Li volatilization loss during solid-state reaction of sintering, mother powder with the same composition as green bodies was usually used to cover the samples, it would waste the expensive raw materials and increase the fabrication cost. In this study, a new method was proposed to prepare the Li6.4La3Zr1.4Ta0.6O12 ceramic solid-state electrolyte where the Li loss is compensated by the outside Li2CO3. Samples prepared by this method have pure garnet phase and compact micromorphology with few pores. These samples have a high Li-ion conductivity of 2.9×10−4 S/cm and a low activation energy of 0.37 eV at room temperature. The electronic conductivity is 1.08×10−8 S/cm, which can be neglected for solid-state electrolyte. [ABSTRACT FROM AUTHOR]

The interface instability between inorganic ceramic electrolytes and lithium metal anodes seriously affects the cycling behavior of high‐performance lithium‐metal batteries. Herein, an in situ interfacial modification strategy is proposed to build the precise hybrid organic/inorganic lithium‐ion conducting layer where the Li1.3Al0.3Ti1.7(PO4)3 (LATP) particle surface is anchored by ion‐conducting covalent organic frameworks (COF) with affluent poly(ethylene glycol) (PEG) moieties. This interlayer features ion transport regulation to avoid high interfacial resistance and enhances interfacial stability by building a functional COF‐based shield against electrons. These as‐prepared particles are employed to fabricate flexible quasi‐solid electrolyte membranes interconnected by polytetrafluoroethylene binder based on the dry process. The obtained membranes perform two‐fold increase in ion conductivity at 30 °C of 2.55 × 10−3 S cm−1 and the prolonged lithium deposition up to 1000 h compared to the pristine, which are attributed to synergistic effects in the inorganic/organic phase. Moreover, an integrated cathode/electrolytes design is proposed and exhibits excellent cycling performance with capacity retention of 98.8% after 200 cycles at 1 C. The corresponding pouch cells can light up LED after bending and recovery. This research provides new insights into the great potential of fabricating soft ceramic‐based membranes in a low‐cost and green way for highly‐stable lithium‐metal batteries. [ABSTRACT FROM AUTHOR]

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 Li-metal 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.