MXene-BN-Introduced Artificial SEI to Inhibit Dendrite Growth of Lithium Metal Batteries.

Lithiophilic substrates have been shown to improve the electrochemical performance of lithium metal anodes. The MXene-BN/Cu 3D current collector was prepared by a filtration method. The artificial solid electrolyte interface (SEI) layer composed of Li3N and LiF was formed on the surface of MXene-BN/Cu during the Li deposition process. Volume changes can be effectively relieved by this special 3D structure. The artificial SEI film reduced the critical dendrite growth length, inhibited Li dendrite growth, and stabilized the electrochemical cycle. MXene-BN/Cu exhibited highly reversible cycling properties during lithium metal deposition with a high Coulombic efficiency of ∼ 98.0% over 500 cycles. Furthermore, LiBH4 was produced during the Li deposition process. This study presents a promising strategy for developing dendrite-free Li anodes for use in lithium metal batteries.

Preparation, Application and Enhancement Dyeing Properties of ZnO Nanoparticles in Silk Fabrics Dyed with Natural Dyes.

In this study, ZnO nanoparticles were prepared by a hydrothermal method with varying the reaction times, material ratios and reaction temperatures. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray Diffraction (XRD) and Fourier infrared spectroscopy (FTIR). It was shown that the material ratio significantly affected the structure and morphology of the synthesized ZnO nanoparticles, and then the uneven nano-octahedral structure, uniform nano-octahedral structure, nano-tubular structure, and nano-sheet structure could be obtained successively. The synthesized ZnO nanoparticles as mordant were used for the dyeing of silk fabrics with different natural dyes (tea polyphenols and hematoxylin). Moreover, they could improve the dyeing properties and fastness (wash and light) on silk fabrics to a certain extent.

Strategic Structure Tuning of Yolk-Shell Microcages for Efficient Nitrogen Fixation.

The electrocatalytic nitrogen reduction reaction (ENRR) under ambient conditions is considered as a promising process to produce ammonia. Towards highly efficient catalysts, here an optimized one-step pyrolysis strategy was tailored to design yolk-shell microcages (YS Co@C/BLCNTs), consisting of Co nanocrystals encapsulated in N-doped carbon framework and bridged by bamboo-like carbon nanotubes (BLCNTs). The cavity created between yolk and shell not only served as a "micro-bag" to store the reactant N2 and enhance its dissolution, but also induced a "cage effect" to confine the diffusion of reaction intermediate, hence making the reaction proceed in the direction of producing NH3 . This catalyst displayed excellent catalytic activities for ENRR: a high NH3 yield of 12.87 µg mgcat -1 h-1 at a high faradaic efficiency of 20.7 % at -0.45 V (vs. reversible hydrogen electrode, RHE). After 5 cycles of consecutive ENRR process, the NH3 yield rate was 11.29 µg mgcat -1 h-1 , indicating the excellent electrocatalytic stability. These results provide a structural engineering for ENRR catalyst with doped N, cooperating with non-precious metal to activate the inert triple bond of N2 and achieve NH3 fixation.

In-Situ Fabrication of Bone-Like CoSe2 Nano-Thorn Loaded on Porous Carbon Cloth as a Flexible Electrode for Na-Ion Storage.

Sodium-ion batteries (SIBs) based on flexible electrode materials are being investigated recently for improving sluggish kinetics and developing energy density. Transition metal selenides present excellent conductivity and high capacity; nevertheless, their low conductivity and serious volume expansion raise challenging issues of inferior lifespan and capacity fading. Herein, an in-situ construction method through carbonization and selenide synergistic effect is skillfully designed to synthesize a flexible electrode of bone-like CoSe2 nano-thorn coated on porous carbon cloth. The designed flexible CoSe2 electrode with stable structural feature displays enhanced Na-ion storage capabilities with good rate performance and outstanding cycling stability. As expected, the designed SIBs with flexible BL-CoSe2 /PCC electrode display excellent reversible capacity with 360.7 mAh g-1 after 180 cycles at a current density of 0.1 A g-1 .