RESUMO
The copper oxide (CuO) nanowires/functionalized graphene (f-graphene) composite material was successfully composed by a one-pot synthesis method. The f-graphene synthesized through the Birch reduction chemistry method was modified with functional group "-(CH2)5COOH", and the CuO nanowires (NWs) were well dispersed in the f-graphene sheets. When used as anode materials in lithium-ion batteries, the composite exhibited good cyclic stability and decent specific capacity of 677 mA·h·g-1 after 50 cycles. CuO NWs can enhance the lithium-ion storage of the composites while the f-graphene effectively resists the volume expansion of the CuO NWs during the galvanostatic charge/discharge cyclic process, and provide a conductive paths for charge transportation. The good electrochemical performance of the synthesized CuO/f-graphene composite suggests great potential of the composite materials for lithium-ion batteries anodes.
RESUMO
A facile strategy was designed for the in situ synthesis of MoS2 nanospheres on functionalized graphene nanoplates (MoS2@f-graphene) for use as lithium-ion battery anode materials. A modified Birch reduction was used to exfoliate graphite into few-layer graphene followed by modification with functional groups. Compared to the most common approach of mixing MoS2 and reduced graphene oxide, our approach provides a way to circumvent the harsh oxidation and destruction of the carbon basal planes. In this process, alkylcarboxyl functional groups on the functionalized graphene (f-graphene) serve as sites where MoS2 nanospheres crystallize, and thus create bridges between the MoS2 nanospheres and the graphene layers to effectively facilitate electronic transport and to avoid both the aggregation of MoS2 and the restacking of graphene. As anode materials, this unique MoS2@f-graphene heterostructure has a high specific capacity of 1173 mAh g-1 at a current density of 100 mA g-1 and a good rate capacity (910 mAh g-1 at 1600 mA g-1).
