Results of theoretical calculations are reported, examining the effect of a coherent twin boundary on the electrical properties of LiCoO(2) . This study suggests that internal interfaces in LiCoO(2) strongly affect the battery voltage, battery capacity, and power density of this material, which is of particular concern if it is used in all-solid-state Li-ion batteries.

Co‐doped silica sol solutions with varying Co composition (Co/(Si+Co)=10–50 mol%) were prepared from tetraethoxysilane and Co(NO3)2·6H2O. Subsequently, these solutions were used in the preparation of hydrogen separation microporous membranes with enhanced hydrothermal stability at 500°C under a steam pressure of 300 kPa. At Co concentrations >33%, the XRD pattern and peak intensity of the Co‐doped silica preparations were similar and were not dependent on Co composition, suggesting that Co was incorporated into the silica network. The best H2 permeation performance in a steam atmosphere (500°C; steam pressure, 300 kPa) was obtained using silica doped with approximately 30 mol% Co. Co‐doped silica membranes (Co 33 mol%) fired at 600°C under a steam partial pressure of 90 kPa showed stable gaseous permeances and a H2 permeance of approximately 2.00–4.00 × 10−6 m3(STP)·(m·s·kPa)−1 with a selectivity of 250–730 (H2/N2), even after 60 h of exposure to steam (steam pressure, 300 kPa) at 500°C.

Atomic-resolution STEM and EELS analysis provide insights into microscopic mechanisms behind oxygen loss and capacity fade in spinel-structured lithium-ion battery cathode material LiMn2O4.

Despite the great progress that has been accomplished in supercapacitors, the imbalance of the development of positive and negative electrode materials still remains a critical issue to achieve high energy density; therefore, exploring high-performance negative electrode materials is highly desirable. In this article, three-dimensional cobalt phosphide (CoP) nanowire arrays were synthesized on a carbon cloth and were utilized as a binder-free supercapacitor negative electrode. The as-synthesized CoP nanowire arrays presented a high capacitance of 571.3 mF/cm at a current density of 1 mA/cm. By using CoP nanowire arrays as the negative electrode and MnO nanowire arrays as the positive electrode, a flexible solid-state asymmetric supercapacitor has been fabricated and has exhibited excellent electrochemical performance, such as a high energy density of 0.69 mWh/cm and a high power density of 114.2 mW/cm. In addition, the solid-state asymmetric supercapacitor shows high cycle stability with 82% capacitance retention after 5000 charge/discharge cycles. This work demonstrates that CoP is a promising negative electrode material for high-performance supercapacitor applications.

A facile synthesis of a new class of reactive porous materials is reported: hierarchically porous hydrogen silsesquioxane (HSiO1.5, HSQ) monoliths with well‐defined macropores and mesopores. The HSQ monoliths are prepared via sol‐gel accompanied by phase separation in a mild condition, and contain micrometer‐sized co‐continuous macropores and high specific surface area reaching up to 800 m2 g−1 because of the small mesopores. A total preservation of Si–H, which is always an issue of HSQ materials, is confirmed by 29Si solid‐state NMR. The HSQ monolith has then been subjected to reduction of noble metal ions to their corresponding metal nanoparticles in simple aqueous solutions under an ambient condition. The nanoparticles produced in this manner are immobilized on the HSQ monolith and are characterized by X‐ray diffraction (XRD) and high angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM). Both the bare HSQ and nanoparticles‐embedded HSQ are promising as heterogeneous catalysts, exhibiting reusability and recyclability.

A novel preceramic polymer suitable to form a SiBCN ceramic was synthesized by hydroboration reaction of 1,3,5-trivinyl-1,3,5-trimethyl-cyclotrisilazane with borane dimethylsulphide. The obtained polymer denoted as polyborosilazane was characterised by FT-IR and NMR spectroscopy and its thermal stability was studied by thermal gravimetric analysis in combination with in situ mass spectrometry TGMS. The polymer-to-ceramic transformation was achieved at 1050c C in inert argon atmosphere yielding black and X-ray amorphous SiBCN ceramics thermally stable up to 1800c C. Using the dip-coating technique, a SiBCN ceramic thin film was formed on a porous alumina substrate. N 2 sorption isotherm analysis revealed that the thin film contained a small amount of micropores of about 0.6 nm in diameter, as well as mesopores between 2.7 and 6 nm in size. The total pore volume was found to be about three orders of magnitude smaller than that of a hydrogen permselective amorphous silica membrane derived from polysilazane. These results indicated potential application of the SiBCN thin film as a molecular sieve membrane suitable for high-temperature separation of small gas molecules like hydrogen below 0.3 nm in size.

Note péÉÅá~ä fëëìÉ Äó dìÉëí bÇáíçêëW lêÖ~åáÅ-íç-fåçêÖ~åáÅ`çåîÉêëáçå mêçÅÉëë Ñçê mçäóãÉê-aÉêáîÉÇ`Éê~ãáÅë póåíÜÉëáë~åÇ`Ü~ê~ÅíÉêáò~íáçå çÑ kçîÉä kçålñáÇÉ pçä-dÉä aÉêáîÉÇ jÉëçéçêçìë^ãçêéÜçìë pá-`-k jÉãÄê~åÉë A novel sol-gel-derived preceramic polymer, namely polyorganosilylcarbodiimide, was synthesized for fabrication of thermally stable amorphous Si-C-N membranes. The gelation process as well as the viscosity of the polyorganosilylcarbodiimide was adjusted for spin coating by reacting a mixture of alkyl and dialkyl chlorosilane monomers with bistrimethylsilylcarbodiimide. The polymeric precursor film was successfully fabricated on a porous substrate by solvent-free spin coating, subsequently converted into a mesoporous amorphous Si-C-N thin film by pyrolysis at 1000c C in Ar. SEM observation as well as N 2 sorption isotherm analysis exhibited the formation of meso-pore channels within the amorphous thin layer. These results indicate that the novel polyorganosilylcarbodiimide developed in this study is suitable for fabricating meso-porous amorphous membranes in the ternary Si-C-N system and with high thermal and chemical stability.

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