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For high-performance silicon–carbon (Si–C)-based anode materials used in high-energy-density lithium-ion batteries (LIBs), there is an urgent need to rationally construct a stable solid electrolyte interface (SEI) film and load a high proportion of silicon content, which is closely related to the capacity and cycling stability of the electrode. Herein, composites of Fe/Fe3C-modified carbon nanofiber–coated Si nanoparticles (Fe/Fe3C–Si@CNFs) were synthesized via a simple electrospinning method. These composites effectively overcome the volume change effect, poor interfacial compatibility and low conductivity, delivering excellent LIB performance. Tested at 2.0 A g−1, Fe/Fe3C–Si@CNFs provides a high reversible capacity of 956.5 mA h g−1 with a coulombic efficiency of more than 99.5% even after 4000 ultra-long stable cycles. The high conductivity of the Fe/Fe3C embedded in the CNF framework can promote e− transfer and boost the Li+ diffusion kinetics in the electrode. The catalytic activity of Fe/Fe3C helps to enhance the interfacial compatibility, grow a balanced stable SEI film and promote the long-cycle stability of the electrode at room temperature. [ABSTRACT FROM AUTHOR]

3D scaffolds and heterogeneous seeds are two effective ways to guide Li deposition and suppress Li dendrite growth. Herein, 3D TiO2 nanotube (TNT) arrays decorated using ultrafine silver nanocrystals (7–10 nm) through cathodic reduction deposition are first demonstrated as a confined space host for lithium metal deposition. First, TiO2 possesses intrinsic lithium affinity with large Li absorption energy, which facilitates Li capture. Then, ultrafine silver nanocrystals decoration allows the uniform and selective nucleation in nanoscale without a nucleation barrier, leading to the extraordinary formation of lithium metal importing into 3D nanotube arrays. As a result, Li metal anode deposited on such a binary architecture (TNT‐Ag‐Li) delivers a high Coulomb efficiency at around 99.4% even after 300 cycles with a capacity of 2 mA h cm−2. Remarkably, TNT‐Ag‐Li exhibits ultralow overpotential of 4 mV and long‐term cycling life over 2500 h with a capacity of 2 mAh cm–2 in Li symmetric cells. Moreover, the full battery with 3D spaced Li nanotubes anode and LiFeO4 cathode exhibits a stable and high capacity of 115 mA h g–1 at 5 C and an excellent Coulombic efficiency of ≈100% over 500 cycles. [ABSTRACT FROM AUTHOR]

Inorganic compounds with different crystalline and amorphous states may show distinct properties in catalytic applications. In this work, we control the crystallization level by fine thermal treatment and synthesize a semicrystalline IrO x material with the formation of abundant boundaries. Theoretical calculation reveals that the interfacial iridium with a high degree of unsaturation is highly active for the hydrogen evolution reaction compared to individual counterparts based on the optimal binding energy with hydrogen (H*). At the heat treatment temperature of 500 °C, the obtained IrO x -500 catalyst has dramatically promoted hydrogen evolution kinetics, endowing the iridium catalyst with a bifunctional activity for acidic overall water splitting with a total voltage of only 1.554 V at a current density of 10 mA cm -2 . In light of the remarkable boundary-enhanced catalysis effects, the semicrystalline material should be further developed for other applications.

The development of advanced luminescent materials is highly desirable for addressing the rising threat of forgery. However, it is challenging to achieve stable full-color upconversion (UC) tuning in the same matrix upon a single-beam light excitation so as to ensure that authentic items are irreproducible. Herein, hexagonal Er/Tm:CsYb 2 F 7 nanocrystals (NCs) embedded inorganic glass via an in situ crystallization strategy is fabricated, which can emit blue, cyan, green, yellow, orange, red and near-infrared (NIR) UC emissions by simply modifying an incident 980 nm laser power. This UC tuning is attributed to the combination roles of the highly efficient laser-induced photothermal effect of the CsYb 2 F 7 host and simultaneous emissions of Er and Tm activators. Importantly, the robust inorganic glass matrix endows Er/Tm:CsYb 2 F 7 NCs with excellent water resistance and the ability to withstand high-power laser irradiation. Based on these unique characteristics, a proof-of-concept anti-counterfeiting experiment is designed. The results indicate that dynamic full-color UC luminescence patterns can be easily tuned by simply changing the power of the incident 980 nm laser. The present work not only confirms that the designed photothermal material can increase information security, but also provides a new idea for practical applications in the field of anti-counterfeiting.

Single-site Au anchored on mpg-C 3 N 4 (519 ppm Au loading) is developed as a highly active, selective, and stable catalyst for the oxidation of silanes with water with a turnover frequency as high as 50 200 h -1 , far exceeding most known catalysts based on total gold content. Other hydrosilanes bearing unsaturated functional groups also lead to corresponding silanols under mild reaction conditions without formation of any side products in good or excellent yields. The spherical aberration correction electron microscopy and extended X-ray absorption fine structure measurements both confirm the atomic dispersion of Au atoms stabilized by mpg-C 3 N 4 . The coordination of the catalytically active Au I by three nitrogen or carbon atoms in the tri-s-triazine repeating units not only prevents the Au atoms from aggregation, but also renders the surface Au I highly active, which is completely different than homogeneous Au I species., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Despite the great importance in fundamental and industrial fields, understanding structural changes for pressure-induced polyamorphism in network-forming glasses remains a formidable challenge. Here, we revisited the local structural transformations in GeO 2 glass up to 54 GPa using x-ray absorption fine structure (XAFS) spectroscopy via a combination diamond anvil cell and polycapillary half-lens. Three polyamorphic transitions can be clearly identified by XAFS structure refinement. First, a progressive increase of the nearest Ge-O distance and bond disorder to a maximum at ~5-16 GPa, in the same pressure region of previously observed tetrahedral-octahedral transformation. Second, a marked decrease of the nearest Ge-O distance at ~16-22.6 GPa but a slight increase at ~22.6-32.7 GPa, with a concomitant decrease of bond disorder. This stage can be related to a second-order-like transition from less dense to dense octahedral glass. Third, another decrease in the nearest Ge-O distance at ~32.7-41.4 GPa but a slight increase up to 54 GPa, synchronized with a gradual increase of bond disorder. This stage provides strong evidence for ultrahigh-pressure polyamorphism with coordination number  >6. Furthermore, cooperative modification is observed in more distant shells. Those results provide a unified local structural picture for elucidating the polyamorphic transitions and densification process in GeO 2 glass.