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Graphene supported transition metal oxides (TMOs) nanocomposites have been recognized as an advisable strategy to develop the advanced electrodes for lithium-ion batteries (LIB) recently, yet the long-term cyclic stability could not be well maintained mainly due to the severe structural collapse and continuous exfoliation of active TMOs from graphene support. Herein, we successfully designed a novel sandwich-type hybrid nanostructure of reduced graphene oxide (rGO) enwrapped MnO nanooctahedra like a blanket (MnO@rGO NO) via a facile solution reflux and a post-annealing. The XRD patterns and FESEM images confirm that octahedral Mn 3 O 4 precursor embedded among GO interlayers could be easily reduced into conformal MnO nanocrystal whilst the full reduction of GO into rGO during the subsequent calcination at 700 °C in N 2 . When used as a promising anode for LIBs, the sandwiched MnO@rGO NO manifests excellent lithium storage capability with high reversible discharge capacity, long-term cyclic stability and superb rate performance, mainly benefiting from the robust structure and good conductivity enhanced by rGO matrix. Even undergoing 600 cycles at the current densities of 400 and 800 mA g −1 , the hybrid sandwiched MnO@rGO NO anodes could still deliver stable discharge capacities of 838 and 687 mAh g −1 , respectively. [ABSTRACT FROM AUTHOR]

Hierarchical hybrid nanostructure of mesoporous ZnFe 2 O 4 nanoparticles anchored on reduced graphene oxide (ZnFe 2 O 4 NPs/rGO) has been successfully developed in this research via a fast low-temperature refluxing method and a subsequent-annealing treatment in N 2 . The unique mesoporous network structures of ZnFe 2 O 4 NPs supported by flexible rGO sheets offer sufficient electrode-electrolyte contact, shorten Li + ions diffusion distance, and thus greatly facilitate the electrochemical reactions via accommodating the volume change efficiently during cycling. Meanwhile, the conductive rGO matrix in the hybrid composite also ensures rapid electron transport to avoid the serve pulverization. Just based on such beneficial synergistic effect, the well-designed hierarchical hybrid ZnFe 2 O 4 NPs/rGO composites present excellent lithium storage performance with high reversible discharge capacity, long-term cycle stability and superb high-rate capability when used as an anode for LIBs. A stable discharge capacity of as high as about 1106.7 mAh g −1 is well maintained even after 400 cycles at the current density of 200 mA g −1 . We think this facile strategy could be further extended to the fabrication of other graphene-based electrodes for advanced energy applications. [ABSTRACT FROM AUTHOR]

NiO nanosheets were anchored at honeycomb amorphous porous carbon with ultrahigh surface area derived from activated wheat husk to obtain NiO@PC (porous carbon). The ultrahigh surface area of PC (634.4 m 2 g −1 ) promoted the attachment of NiO nanosheets, and this hierarchical nanostructure (NiO@PC) was beneficial for facilitating electron and electrolyte ion transport and accelerating the reversible redox reaction, which successfully demonstrated its high energy storage properties as supercapacitor. The NiO@PC composite exhibited brilliant capacitance of 500 F g −1 at 10 A g −1 after 8000 cycles. Moreover, as symmetric supercapacitor, NiO@PC exhibited high specific capacitance of 76 mF cm −2 at 1 mA cm −2 . The excellent electrochemistry performance of NiO@PC brings the possibility of using biomass waste as electrode materials for energy storage. This process is facile and environmental friendly. [ABSTRACT FROM AUTHOR]