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A simple preparation method of the anode is designed for sodium ion battery. The bimetallic selenide (CoSe 2 /ZnSe) and nitrogen-doped carbon composite materials are obtained by selenization and carbonization of the metal organic framework precursors, and applied to high-performance sodium ion storage. The ingenious nanostructure is shown in that CoSe 2 and ZnSe nanoparticles are evenly distributed on the fusiform flake carbon skeleton. This synergy can improve the capacity and conductivity, and inhibit the volume expansion during the cycle. For electrochemical performance analysis, the prepared 1:1-CoSe 2 /ZnSe@NCC electrode shows a high discharge specific capacity of 621.5 mA h g-1 at 0.1 A g-1 after 100 cycles (coulomb efficiency close to 100%, capacity retention reaches ~ 90%), and has advantages over other electrodes in terms of rate performance and reaction kinetics. The excellent electrochemical performance confirms the successful development of a high performance electrode for sodium ion storage by this strategy. [ABSTRACT FROM AUTHOR]

Hollow and porous three-dimensional Co(Ni)Se 2 /N-doped carbon composite particles prepared by a simple process using metal organic framework (MOF) precursors as the template are used as a high-efficiency anode material for sodium ion batteries. The composite material having a regular rhombohedral dodecahedral structure contains the N-doped porous carbon shell and the nano-metal selenide (CoSe 2 and NiSe 2) embedded in the carbon shell. Moreover, the metal selenide has a high capacity density, and the N-doped porous carbon structure can enhance the electrical conductivity and structural stability of the material to suppress volume expansion. Their effective synergistic combination shows excellent electrochemical performance. As the anode of the sodium ion battery, Co(Ni)Se 2 @NCC exhibits a very high specific capacity of up to 735.2 mA h g−1 after 100 cycles and superior rate performance. In addition to these, excellent kinetic performance and cycle stability and coulombic efficiency are sufficient to prove that this material has broad prospects in sodium-ion battery anodes. [ABSTRACT FROM AUTHOR]

Abstract In this work, an eco-friendly and convenient microwave-assisted synthesis technique was applied in the entire experiment course. The first obtained graphene-Ni composite possess an unsatisfactory microwave absorption capacity due to unbalanced matching nature. Then a sulfurization process was tried at different temperatures to convert Ni into NiS/Ni 3 S 2 , and an innovative graphene-NiS/Ni 3 S 2 composite with a hierarchical architecture was fabricated under the condition of microwave irradiation. The investigation into microwave absorbing performances manifests that the absorption property of graphene-Ni can be obviously improved by sulfurization method. The results show, compared with graphene-Ni, the hierarchical-architecture graphene-NiS/Ni 3 S 2 composites generated at 150 ℃ (S-150) possess excellent absorbing ability with a maximum RL as strong as − 55.1 dB at 6.0 GHz with a thickness of 2.7 mm, and the effective bandwidth covers 8.6 GHz from 2.8 to 11.4 GHz with thickness varies in 1.5–4.5 mm range. The enhanced performances for S-150 mainly derive from the synergy of superior impedance matching character, high attenuation, dielectric loss and plenteous interface polarizations. [ABSTRACT FROM AUTHOR]

Abstract: Flower-like Zn2SnO4 composites had been prepared through a green hydrothermal synthesis. The structural, morphological and electrochemical properties were investigated by means of XRD, BET, SEM, TEM, and electrochemical measurement. The results show that the as-prepared sample is in high purity phase and of good crystallinity; meanwhile it has a particular 3-D structure and large surface area. Electrochemical measurement suggests that flower-like Zn2SnO4 composites exhibit better cycling properties and lower initial irreversible capacities than the solid Zn2SnO4 cubes. The first discharge and charge capacities of the material are 1750mAhg−1 and 880mAhg−1 respectively. A higher reversible capacity of 501mAhg−1 was obtained after 50 cycles at a current density of 300mAg−1. The higher reversible capacity and good stability can be related to the special nanostructural features of the material. Such Zn2SnO4 structures synthesized by the simple and cheap method are expected to have potential application in energy storage. [Copyright &y& Elsevier]