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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]

Graphene supported porous Si@C ternary composites had been synthesized by various routes and their structural, morphological and electrochemical properties were investigated. Porous Si spheres coated with carbon layer and supported by graphene have been designed to form a 3D carbon conductive network. Used as anode materials for lithium ion batteries, graphene supported porous Si@C ternary composites demonstrate excellent electrochemical performance and cycling stability. The first discharge capacity is 2184.7 mA h/g at a high current density of 300 mA/g. After 50 cycles, the reversible capacity is 652.4 mA h/g at a current density of 300 mA/g and the coulomb efficiency reaches at 98.7%. Due to their excellent electrochemical properties, graphene supported porous Si@C ternary composites can be a kind of promising anode materials for lithium ion batteries. [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]

Abstract: Polypyrrole-coated hollow Zn2SnO4 boxes (hollow Zn2SnO4@PPY nanocomposites) had been prepared by a microemulsion polymerization. The structural, morphological and electrochemical properties were methodically investigated by means of XRD, TGA, BJH (pore size distribution analysis), SEM, TEM, and electrochemical measurements. Results show that the hollow Zn2SnO4 boxes with the uniform and cube like structure are coated by PPY. Electrochemical measurement suggests that hollow Zn2SnO4@PPY composites exhibit better cycling properties and lower initial irreversible capacities as anode materials for lithium-ion batteries. At a current density of 60mA/g in the voltage about 0.01–3.0V, the first discharge–charge capacities of hollow Zn2SnO4@PPY composites are 1105.2mAh/g and 556mAh/g. After 50 cycles, a specific charge capacity of 478.4mAh/g remained and the coulombic efficiency reaches 98.2%, revealing better capacity retention compared with hollow Zn2SnO4 boxes. [Copyright &y& Elsevier]

Abstract: The GNS/Li2SnO3/PPY ternary composites were synthesized by a deoxidation technique. The soft polymer matrix and flexible graphene provide a dual buffering structure for Li2SnO3 which synergistic leads to improved stability, enhanced electric conductivity and better electrochemical performance. The GNS/Li2SnO3/PPY composites tested as anode materials for lithium ion batteries exhibit a high reversible capacity of 699.4mAh/g over 30 cycles, which is much better than that of pure Li2SnO3, PPY/Li2SnO3 and GNS/Li2SnO3 composites. [Copyright &y& Elsevier]

Abstract: The carbon-doped Li2SnO3/graphene composites for lithium-ion batteries were synthesized by the hydrothermal route. The structure, morphology and electrochemical properties of the composites were detected by means of XRD, SEM, TEM, Raman, TGA and electrochemical measurements. The Li2SnO3 nanoparticles are surrounded by graphene sheets (GNS) and amorphous carbon layers. The carbon-doped Li2SnO3/graphene materials exhibit good electrochemical performance with high capacity and good cycling stability (736.3mAh/g after 50 cycles at 60mA/g).The presence of graphene sheets and carbon layer can alleviate the effects of volume changes, keep the structure stable and increase the conductivity. Conclusively, The C/Li2SnO3/GNS composites exhibit better electrochemical properties than GNS/Li2SnO3 and Li2SnO3. [Copyright &y& Elsevier]