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CuO–Cu 2 O/graphene composite has been successfully prepared by the combination of a microwave-assisted process and subsequent annealing. X-ray diffraction and electron microscopy reveals that copper oxide nanospheres with a size of 120–200 nm are uniformly anchored on graphene nanosheets. The copper oxide nanospheres are composed of numerous CuO and Cu 2 O nanocrystals of ∼10 nm. These nanospheres are hollow and the thickness of the shells is around 50–70 nm. The CuO–Cu 2 O/graphene composite shows a highly reversible capacity and excellent rate performance as anode for Li-ion battery. The reversible capacity of the composite retains 487 mA h g −1 after 60 cycles at 200 mA g −1 . Even when cycled at various rate (200, 500, 1000, 2000, 5000 mA g −1 ) for 60 cycles, the capacity can recover to 520 mA h g −1 at the current of 200 mA g −1 . The enhanced electrochemical performances are ascribed to the hollow spherical architectures, excellent conductivity of graphene sheets, and possible synergistic effects between CuO, Cu 2 O and graphene that enhance the intrinsic properties of each component. [ABSTRACT FROM AUTHOR]

The uneven dispersion of MnO easily leads to local volume change, resulting in the crushing and pulverizing of electrode. Herein, a spongy three-dimensional (3D) porous MnO/C composite was fabricated by pyrolysis of the double-network (DN) aerogel composed of agar (AG) and Mn-crosslinked sodium alginate (SA). The spongy MnO/C composite has homogeneous distribution and uniform size ultrafine MnO nanoparticles embedded into 3D porous carbon network and shows high BET surface area of 363 m2 g−1, which can not only improve the electrical conductivity, but effectively confine the expulsion of MnO and restrain the crushing and pulverizing of electrode. As anode for LIBs, the spongy MnO/C composite exhibits superior rate capability (574 mAh g−1, 2 A g−1) and excellent cycling stability. The capacity gradually increases during the cycling process, reaching 1270 mAh g−1 after 500 cycles at 2 A g−1. The rising capacity can be attributed to the following reasons: 1) more Mn2+ was oxidated to higher valence, 2) The enhanced amorphism of MnO improves Li+ diffusion kinetics, 3) the reversible form and decomposition of SEI. • A spongy three-dimensional porous MnO/C composite was fabricated. • MnO/C composite has homogeneous ultrafine MnO nanoparticles and high BET surface area. • MnO/C composite exhibits excellent rate capability and cycling stability. • MnO/C composite is a potential anode material. [ABSTRACT FROM AUTHOR]

Abstract: Sn–C nanocomposite is a promising anode material for high performance lithium-ion battery, but suffers from a complex synthesis procedure which hider its practical applicability. We report a simple and cheap synthesis method for Sn–C nanocomposites. By combining wet-chemical and carbonthermal reduction approaches, we are able to produce Sn–C nanocomposite in a simple one-pot synthesis during a successive heating procedure. Gel-derived nanocrystalline SnO2 is introduced into the precursor to act as a transition-phase for in situ growth of metallic tin nanocrystals. Consequently, this method allows for the fine control of the formation of the tin nanocrystals posterior to the carbonization of carbon sources through carbonthermal reduction of a nanosized SnO2. The resulting Sn–C nanocomposites deliver a remarkable lithium-ion insertion/extraction performance, such as high capacities of 588 and 367mAhg−1 at 20mAg−1 and 200mAg−1, respectively. [Copyright &y& Elsevier]