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We report a synthetic scheme for preparing a SnO2-Sn-carbon triad inverse opal porous material using the controlled sintering of Sn precursor-infiltrated polystyrene (PS) nanobead films. Because the uniform PS nanobead film, which can be converted into carbon via a sintering step, uptakes the precursor solution, the carbon can be uniformly distributed throughout the Sn-based anode material. Moreover, the partial carbonization of the PS nanobeads under a controlled Ar/oxygen environment not only produces a composite material with an inverse opal-like porous nanostructure but also converts the Sn precursor/PS into a SnO2-Sn-C triad electrode. [ABSTRACT FROM AUTHOR]

Morphology-controlled MoS2 nanosheets were successfully synthe-sized with the aid of graphene/acid coexistence by a one-pot hydrothermal method. The ultrathin MoS2 nanosheets were self-assembled into a cockscomb-like structure with an exposed (100) facet on graphene sheets, which is in strong contrast to large aggregate MoS2 plates grown freely on graphene sheets without acetic acid. The ultrathin MoS2 nanosheets displayed excellent rate performance for Li storage (709 mAh-g-1 capacity at 8320 mA-g-1 discharging rate) and superior charge/discharge cydability. [ABSTRACT FROM AUTHOR]

Silicon is a promising candidate for electrodes in lithium ion batteries due to its large theoretical energy density. Poor capacity retention, caused by pulverization of Si during cycling, frustrates its practical application. We have developed a nanostructured form of silicon, consisting of arrays of sealed, tubular geometries that is capable of accommodating large volume changes associated with lithiation in battery applications. Such electrodes exhibit high initial Coulombic efficiencies (i.e., >85%) and stable capacity-retention (>80% after 50 cycles), due to an unusual, underlying mechanics that is dominated by free surfaces. This physics is manifested by a strongly anisotropic expansion in which 400% volumetric increases are accomplished with only relatively small (<35%) changes in the axial dimension. These experimental results and associated theoretical mechanics models demonstrate the extent to which nanoscale engineering of electrode geometry can be used to advantage in the design of rechargeable batteries with highly reversible capacity and long-term cycle stability. [ABSTRACT FROM AUTHOR]