No abstract

Mo 6 S 8 Chevrel-phase (CP) cathode materials, for Mg secondary batteries, have been reported to be better suited and superior to other cathode materials. We synthesized Cu x Mo 6 S 8 (Cu-CP) by varying the temperature and time and found different crystalline structures of Cu-CP, depending on the time and temperature of the growth process. Using these structures as precursors for preparing cathodes was shown to influence the performance of the electrochemical cell. After etching Cu from Cu-CP, the structure was stabilized as the rhombohedral phase of Mo 6 S 8 (CP). The morphologies of Cu-CP and CP were examined by scanning electron microscopy, and the structures were confirmed using X-ray diffraction. The coin-cell structure was fabricated, and the electrochemical properties of CP were evaluated and compared for different crystalline structures of Cu-CP. The discharge capacities were improved from 84.2 to 122.9 mAh•g −1 as the structure of Cu-CP changed from rhombohedral to triclinic.

This study demonstrated that hydrophobic pore surfaces and hydrophilic membrane surfaces are more favorable in enhancing water flux, providing an important insight into the development of high performance membranes.

The Chevrel phase (CP) (Mo6S8), which is used as an electrode material in Mg rechargeable batteries, has a capacity limit owing to ion insertion and trapping. To address this problem, we modify the wire structure of the CP. Mo6S3I6 nanowires, in which iodiene is substituted for Mo6S9 nanowires as infinite CP structures, can be synthesized in various ways. When synthesizing stoichiometrically, an unwanted secondary phase may appear. We solved these problems by reducing the synthesis time. Electrochemical analysis was performed using these nanowires as an active material in Mg batteries.

TiN has beneficial physicochemical properties, such as high hardness, good chemical inertness, and good corrosion resistance. TiN has been used for optical filters and protective coatings to exploit these properties. We deposited TiN using atomic layer deposition as a capping layer for a pellicle. We investigated the hydrogen plasma resistance using Raman spectroscopy, transmission electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. As the hydrogen plasma exposure time increased, bonds formed between the TiN film and nitrogen compounds. With long-term exposure, the thickness of the TiN film decreased owing to etching.

The mechanical properties of nanometer-thick graphite film (NGF) and graphene were characterized using a bulge test. Young’s modulus, fracture stress, residual strain and stress of the NGF were measured. The NGF was synthesized on a Ni/SiO2/Si substrate using a chemical vapor deposition system. Large-area freestanding NGF was prepared via camphor transfer. Young’s modulus, fracture stress and fracture strain of the NGF were 106[Formula: see text]GPa, 462[Formula: see text]MPa, and 0.3%, respectively, confirming that the bulge test is a very useful technique for evaluating the mechanical properties of NGF. A bulge test was performed to evaluate the mechanical properties of graphene with a free-standing poly (bisphenol A carbonate) (PC)/graphene layer. Large-area freestanding PC/2D material layers were prepared by peeling-off and stamping. The PC layer was used as the supporting layer in this study. Young’s modulus of graphene was calculated from Young’s modulus of the PC/2D material layers and PC layers using the rule of mixtures. Young’s modulus of the graphene was 260[Formula: see text]GPa. The results of this study confirm the efficacy of the bulge test for determining the mechanical properties of nanometer-thick films and 2D materials, including graphene.