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Abstract Inorganic fillers play an important role in improving the ionic conductivity of solid composite electrolytes (SCEs) for Li‐ion batteries. Among inorganic fillers, perovskite‐type lithium lanthanum titanate (LLTO) stands out for its high bulk Li+ conductivity on the order of 10−3 S cm−1 at room temperature. According to a literature survey, the optimal LLTO filler should possess the following characteristics: i) a single‐crystal structure to minimize grain boundaries; ii) a small particle size to increase the filler/polymer interface area; iii) a 1D morphology for efficient interface channels; and iv) cubic symmetry to facilitate rapid bulk Li+ diffusion within the filler. However, the synthesis of single crystal, 1D LLTO nanomaterials with cubic symmetry is challenging. Herein, a flux strategy is developed to synthesize La0.5M0.5TiO3 (LMTO, M═Li, Na, and K) single‐crystal nanorods with an A‐site‐disordered, cubic perovskite phase. The flux media promotes the oriented growth of nanorods, prevents nanorods from sintering, and provides multiple alkali metal ion doping at M sites to stabilize the cubic phase. SCEs compositing the Li+‐conducting LMTO nanorods as fillers and poly[vinylene carbonate‐co‐lithium sulfonyl(trifluoromethane sulfonyl)imide methacrylate] matrix exhibit more than twice the conductivity of the neat polymer electrolyte (30.6 vs 14.0 µS cm−1 at 303 K).

Abstract Materials keeping thickness in atomic scale but extending primarily in lateral dimensions offer properties attractive for many emerging applications. However, compared to crystalline counterparts, synthesis of atomically thin films in the highly disordered amorphous form, which avoids nonuniformity and defects associated with grain boundaries, is challenging due to their metastable nature. Here we present a scalable and solution-based strategy to prepare large-area, freestanding quasi-2D amorphous carbon nanomembranes with predominant sp2 bonding and thickness down to 1–2 atomic layers, from coal-derived carbon dots as precursors. These atomically thin amorphous carbon films are mechanically strong with modulus of 400 ± 100 GPa and demonstrate robust dielectric properties with high dielectric strength above 20 MV cm−1 and low leakage current density below 10−4 A cm−2 through a scaled thickness of three-atomic layers. They can be implemented as solution-deposited ultrathin gate dielectrics in transistors or ion-transport media in memristors, enabling exceptional device performance and spatiotemporal uniformity.

Molecular dynamics simulations were used to study deformation-induced face-centered cubic (fcc) to body-centered cubic (bcc) transformation during uniaxial compression of an 80Fe-20Ni (at%) alloy with and without precipitates. Our purpose was to better understand recent experimental results in an Fe-Ni-based medium-entropy alloy where certain precipitates were found to constrain the fcc to bcc transformation. We find that larger precipitates and smaller spacings between precipitates hinder the phase transformation by impeding relaxation of internal elastic strains. These results deconvolute the individual effects of precipitate size and spacing and help interpret the experimental results where only their combined effects could be measured.

Single and few-layers MoS2 were uniformly grown on the surface of chemically reduced graphene oxide (r-GO), via a facile liquid phase approach. The method is based on a simple functionalization of r-GO with oleyl amine which seems to affect significantly the MoS2 way of growth. Scanning-transmission-electron microscopy (STEM) analysis revealed the presence of single-layer MoS2 on the surface of a few-layers r-GO. This result was also confirmed by atomic-force microscopy (AFM) images. X-ray photoemission spectroscopy (XPS) and Raman spectroscopy were used for in-depth structural characterization. Furthermore, we have successfully applied the method to synthesize MoS2 nanocomposites with multi wall carbon nanotubes (CN) and carbon nanofibers (CNF). The results demonstrate clearly the selective MoS2 growth on both carbon-based supports.

High-resolution aberration-corrected electron microscopy was performed on a series of catalysts derived from a parent material, 2 at.% Au/Fe2O3 (WGC ref. no. 60C), prepared by co-precipitation and calcined in air at 400°C, and a catalyst prepared by leaching surface gold from the parent catalyst and exposed to various treatments, including use in the water–gas shift reaction at 250°C. Aberration-corrected JEOL 2200FS (JEOL USA, Peabody, MA) and Vacuum Generators HB-603U STEM instruments were used to image fresh, reduced, leached, used and re-oxidized catalyst samples. A new in situ heating technology (Protochips Inc., Raleigh, NC, USA), which permits full sub-Ångström imaging resolution in the JEOL 2200FS was used to study the effects of temperature on the behavior of gold species. A remarkable stability of gold to redox treatments up to 400°C, with atomic gold decorating step surfaces of iron oxide was identified. On heating the samples in vacuum to 700°C, it was found that monodispersed gold began to sinter to form nanoparticles above 500°C. Gold species internal to the iron oxide support material was shown to diffuse to the surface at elevated temperature, coalescing into discrete nanocrystals. The results demonstrate the value of in situ heating for understanding morphological changes in the catalyst with elevated temperature treatments. [ABSTRACT FROM AUTHOR]