Haiwei Wu

Graphene supported Li2SnO3 as anode material for lithium-ion batteries

The graphene supported Li2SnO3 composites were prepared via a deoxidation technique. The structure, morphology and electrochemical properties of the composites were detected by means of XRD, SEM, TEM, Raman, TGA and electrochemical measurements. The Li2SnO3 powders could be distributed on the graphene sheets (GNS). The Li2SnO3/GNS composites exhibit good electrochemical performance with high capacity and good cycling stability (582.2 mAh/g after 50 cycles at 60 mA/g). The performance is ascribed to the presence of graphene keeping the structure stable. The composites Li2SnO3/GNS exhibited a better electrochemical property than Li2SnO3 and graphene.

Flower-like α-Fe2O3/ordered mesoporous carbon nanocomposite and its enhanced microwave absorption property

Abstract Three-dimensional flower-like α-Fe2O3 structures were grown on the surface of ordered mesoporous carbon nanorods through a facile hydrothermal method, and their electromagnetic (EM) parameters were measured at 2–18 GHz. The special geometric morphology and proper magnetic loss of α-Fe2O3 nanoparticles and the strong dielectric polarisations and relaxations in the composites contribute to its excellent EM wave absorption. A reflection loss exceeding −10 dB was obtained at 9·9–16·1 GHz for an absorber of 50 wt-% loading with 2·50 mm thickness layer. The result provides a novel EM wave absorbing material to meet the practical applications.

Controlled synthesis of hollow Si–Ni–Sn nanoarchitectured electrode for advanced lithium-ion batteries

A Sn-based intermetallic compound (hollow Si–Ni–Sn nanospheres) with a porous and hollow microspheric structure was fabricated via a versatile template synthesis approach followed by an in situ chemical reaction, and directly used as an anode material for lithium-ion batteries (LIBs). The hollow Si–Ni–Sn nanosphere anode with a unique architecture exhibits high initial discharge capacity and excellent cycling stability. The reversible capacity of hollow Si–Ni–Sn nanospheres is 1065 mA h g−1 and is maintained at 402 mA h g−1 after 50 cycles, which is much higher than that of hollow SiO2@Ni@SnO2 nanospheres. The unique configuration of the Sn-based intermetallic compound presents a beneficial approach to create efficient and practical electrodes for energy storage applications.

Synergetic effect of hexagonal nitride nanopowder and graphene nanosheets on thermal and electrical conductivity of the hBN/GNs/CE resin nanocomposites

Abstract In the study, two kinds of nanomaterials [hexagonal nitride nanopowder (hBN) and graphene nanosheets (GNs)] were chosen as resin fillers due to their similar structures and excellent thermal properties. The hBN/CE, GNs/CE and hBN/GNs/CE resin nanocomposites with different hBN and/or GNs contents were prepared by a solution blended method. The structures of hBN and GNs, thermal and electrical conductivities, and thermal properties of the hBN/CE, GNs/CE and hBN/GNs/CE resin nanocomposites were observed with different test instruments. The results showed that the hBN had an analogous structure with GNs. The addition of hBN and GNs in the CE resin made the fractural surfaces of the resin nanocomposites rougher and more fold than that of the pure CE resin. For thermal conductivity, the synergistic effect of the hBN and GNs in the CE resin nanocomposites was better than the hBN or GNs filling the CE resin alone. The thermal diffusivity of GNs was good, meanwhile, the electrical conductivity of GNs was excellent as well. It indicated that the electrical conductivity of the GNs/CE resin nanocomposites was higher than that of the hBN/GNs/CE resin nanocomposites at a given volume contents. The data calculated from the TGA test was roughly corresponding to the experimental hBN and GNs volume content of the hBN/GNs/CE resin nanocomposites.

Electroless Cu/Ni Plating on Graphite Flake and the Effects to the Properties of Graphite Flake/Si/Al Hybrid Composites

Proper process and parameter were investigated to coat Cu or Ni on graphite flake (Gf) by electroless plating. Microstructural characterization indicated that the Cu/Ni was coated on the Gf uniformly and comprehensively. Then aluminum matrix composites reinforced with Si and graphite were fabricated by a unique vacuum gas pressure infiltration. The thermal conductivity and mechanical properties of the composites, both with and without Cu or Ni coating layers on the graphite surface, have been studied. The obtained results indicated that the mechanical property of the Cu or Ni coated Gf/Si/Al composites dramatically increased, as compared with the non-coated Gf/Si/Al composite. In the meantime, Cu or Ni coated Gf proved to have better wettability and interfacial bonding with the aluminum matrix, which were expected to be a highly sustainable and dispersible reinforcement for metal matrix composites.