Chongyun Wang

Novel phase change behavior of n-eicosane in nanoporous silica: emulsion template preparation and structure characterization using small angle X-ray scattering

Silica microcapsules with hierarchical pore structure are prepared using a one step emulsion templated hydrolysis method. Silica particles of around 100 nm with percolated nanosized pores are self-assembled into micrometer scale spherical shells. The porous structure serves as an ideal host for shape stabilization of melted organic compounds. Small angle X-ray scattering (SAXS) results show that the n-eicosane encapsulated in nanoporous silica consists of mass fractal structure with a fractal dimension of 2.1. n-Eicosane encapsulated in the nanosized pores exhibits novel phase change behavior. A large melting point drop from 37.0 to 28.8 °C is observed, which is attributed to the strong interaction between the n-eicosane molecules and the silica skeleton.

Porous Mg thin films for Mg–air batteries

An alkaline primary Mg-air battery made from a porous Mg thin film displayed superior discharge performances, including a flat discharge plateau, a high open-circuit voltage of 1.41 V and a large discharge capacity of 821 mAh g(-1), suggesting that the electrochemical performances of Mg-air batteries can be improved by controlling the Mg anode morphology.

Improved electrochemical hydrogen storage properties of Mg-Y thin films as a function of substrate temperature

Abstract Pd-capped Mg78Y22 thin films have been prepared by direct current magnetron co-sputtering system at different substrate temperatures and their electrochemical hydrogen storage properties have been investigated. It is found that rising substrate temperature to 60 °C can coarsen the surface of thin film, thus facilitating the diffusion of hydrogen atoms and then enhancing its discharge capacity to ~1725 mAh·g−1. Simultaneously, the cyclic stability is effectively improved due to the increased adhesion force between film and substrate as a function of temperature. In addition, the specimen exhibits a very long and flat discharge plateau at about −0.67 V, at which nearly 60% of capacity is maintained. The property is favorable for the application in metal hydride/nickel secondary batteries. The results indicate that rising optimal substrate temperature has a beneficial effect on the electrochemical hydrogen storage of Mg-Y thin films.