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Abstract: The surface of graphene is modified by nickel nanoparticles which are in-situ reduced from NiO nanoparticles by graphene. The nickel nanoparticles obtained are up to 10nm in size and are strongly anchored on the surface of graphene sheets. As an anode material for lithium ion batteries, the graphene–Ni hybrid material delivers a reversible capacity of 675mAhg−1 after 35 discharge/charge cycles at a current density of 100mAg−1, corresponding to 85% retention of the initial charge capacity. In addition, the graphene–Ni hybrid electrode exhibits much better rate capability compared to its pure counterpart operated at various rates between 200 and 800mAg−1. Such enhanced lithium storage performance of the graphene–Ni hybrid electrode can be ascribed to the enhanced electronic transport and Li+ migration through the solid electrolyte interphase (SEI) film as a consequence of that the anchored nickel nanoparticles increase the electronic conductivity and modify the structure of SEI film covering the surface of graphene. [Copyright &y& Elsevier]

Scrupulous design and fabrication of advanced anode materials are of great importance for developing high-performance lithium ion batteries. Herein, we report a facile strategy for construction of free-standing and free-binder 3D porous carbon coated MoS 2 /nitrogen-doped graphene (C-MoS 2 /N-G) integrated electrode via a hydrothermal-induced self-assembly process. The preformed carbon coated MoS 2 is strongly anchored on the porous nitrogen-doped graphene aerogel architecture. As an anode for lithium ion batteries, the C-MoS 2 /N-G electrode delivers a high first discharge capacity of 1600 mAh g −1 and maintains 900 mAh g −1 after 500 cycles at a current density of 200 mA g −1 . Impressively, superior high-rate capability is achieved for the C-MoS 2 /N-G with a reversible capacity of 500 mAh g −1 at a high current density of 4000 mA g −1 . Furthermore, the lithium storage mechanism of the obtained integrated electrode is investigated by ex-situ X-ray photoelectron spectroscopy and transmission electron microscopy in detail. [ABSTRACT FROM AUTHOR]

Abstract: Relatively small hysteresis in voltage, appropriate electromotive force and low average delithiation voltage make MnO, among many transition metal oxides. MnO/reduced graphene oxide sheet (MnO/RGOS) hybrid is synthesized by a two-step electrode design consisting of liquid phase deposition of MnCO3 nanoparticles on the surface of graphene oxide sheets followed by heat treatment in flowing nitrogen. As an anode for Li-ion batteries, the MnO/RGOS hybrid electrode shows a reversible capacity of 665.5 mA h g−1 after 50 cycles at a current density of 100 mA g−1 and delivers 454.2 mA h g−1 at a rate of 400 mA g−1, which is obviously better than that of bare MnO electrode. Those reasons for such enhanced electrochemical properties are investigated by galvanostatic intermittent titration technique (GITT) as well as electrochemical impedance spectroscopy (EIS). The probable origins, in the term of thermodynamic and kinetic factors, for the marked hysteresis in voltage observed between charge and discharge are also discussed. [Copyright &y& Elsevier]

Abstract: A NiO–graphene hybrid is synthesized by a liquid phase deposition method. As an anode material for lithium ion batteries, the cyclic stability and rate capability of NiO is significantly improved after the incorporation of graphene sheets. The NiO–graphene hybrid electrode delivers a capacity of 646.1mAhg−1 after 35cycles at a current density of 100mAg−1, corresponding to 86.3% capacity retention. When the current density is increased to 400 and 800mAg−1, it still maintains a capacity of 509 and 368.5mAhg−1, respectively. The thermodynamic and kinetic properties of NiO electrodes with and without graphene are investigated by galvanostatic intermittent titration technique. The relationship between the rate and voltage hysteresis is also discussed. The polarization of both the electrodes in all cases obeys ohmic rule in the present rate range. The incorporation of graphene sheets can partly reduce the voltage polarization thereby the voltage hysteresis with increasing the current density. However, the extrapolation to zero current ends up in an approximate residual voltage for both the NiO electrodes. [Copyright &y& Elsevier]