Mingyue Wang

Preparation and application of hollow ZnFe2O4@PANI hybrids as high performance anode materials for lithium-ion batteries

ZnFe2O4, a type of mixed transition metal oxide, is considered as one of the most attractive potential anode materials for LIBs due to its high reversible capacity and satisfactory structural stability. However, the low conductivity and the serious volume exchange during the electrochemical process are still two main issues for ZnFe2O4. In this study, we first designed conductive PANI layer coated hollow ZnFe2O4 nanospheres by micro emulsion polymerization. Two strategies of hollow structure and PANI coating were attempted to relieve expansion and increase conductivity. The results show that the as-designed hollow ZnFe2O4@PANI composites exhibited a large initial specific capacity of 1489.38 mA h g−1 with the first discharge that is maintained at over 607.3 mA h g−1 even after 50 charge–discharge cycles.

Laser additive manufacture of titanium alloys

Titanium alloys are highly adaptive to the manufacture of military, aircraft and medical devices due to their high tensile strength and toughness. However, the traditional processing path of titanium alloys are difficult and costly, which restricted the wide applications of titanium alloys. Additive manufacture has provided new processing routings for titanium alloys, with which high qualified components can be produced efficiently. Selective laser melting and laser metal deposition are two frequently used processing routings for additive manufacture of titanium alloys; while the former is powder bed based and can be used to produce fine components, the latter is powder feeding based and can be utilised to produce large components. With different forming mechanisms, the processing routings exhibit different characteristics in forming capacities, surface roughness, inner microstructures and mechanical properties, during their applications on titanium alloys. The development, characteristics and the applications of these two techniques in titanium alloys are reviewed, and the future developments of laser additive manufacture of titanium alloys are also discussed.

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.

Design and microwave absorption properties of thistle-like CoNi enveloped in dielectric Ag decorated graphene composites

A novel hierarchical composites for coupling thistle-like CoNi with dielectric Ag decorated graphene in paraffin wax as high performance microwave absorber has been synthesized by a facile two-step strategy. The components, particle size, microstructure and morphology of the resulting composites are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectra, scanning electron microscope, transmission electron microscopy and energy dispersive X-ray spectroscopy, etc. Due to the unique flower structure and good synergistic effect of dielectric loss and magnetic loss, thistle-like CoNi@dielectric Ag decorated graphene composites have showed glorious microwave absorption intensity and frequency width. The maximum reflection loss of -61.9 dB can be gained at 6.96 GHz, which has rarely been reported yet. In addition, the corresponding effective bandwidth with reflection loss less than -10 dB is 5.6 GHz ranging from 12.4 to 18 GHz at only 1.67 mm thickness. This highly efficient and broad band features endow thistle-like CoNi@dielectric Ag decorated graphene composites with promising applications in microwave absorption, electromagnetic shielding, information safety, direct broadcast satellite and military radar fields.

Synthesis of graphene/thorns-like polyaniline/α-Fe2O3@SiO2 nanocomposites for lightweight and highly efficient electromagnetic wave absorber

α-Fe2O3@SiO2 nanoparticles have been successfully enveloped in graphene nanosheets/thorns-like polyaniline matrix (RGO/thorns-like PANI/α-Fe2O3@SiO2 nanocomposites) by some facile strategies. The measured electromagnetic parameters indicate that the interfacial polarization, the charge transfer, the multiple reflections and scatterings, the Debye dipolar relaxation processes, the magnetic loss, the quarter-wavelength matching and the well-matched characteristic impedance all play significant roles in improving the electromagnetic wave absorption performance. The maximum reflection loss of RGO/thorns-like PANI/α-Fe2O3@SiO2 nanocomposites reaches -50.06 dB at 14.4 GHz with a matching thickness of only 2.3 mm, and the absorption bandwidth with reflection loss less than -10 dB is in the 4.0-18.0 GHz range for the absorber thickness of 1.5-5.5 mm. Moreover, the adding quantity of nanocomposites in the paraffin matrix is only 16.7 wt%. Consequently, it is believed that the nanocomposites could be used as an excellent electromagnetic wave absorber with lightweight, thin thickness, broad bandwidth and strong absorption.