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Flower-like β-Ni(OH) 2 encapsulated by flexible reduced graphene oxide (rGO) nanosheets have been synthesized by one-pot hydrothermal process and were used as Faradaic electrodes for supercapacitors. β-Ni(OH) 2 microflowers whose particle sizes ranging from 1.7 to 2.5 μm were effectively encapsulated by flexible rGO nanosheets. Due to the efficient charge transfer and unimpeded ion transports, such β-Ni(OH) 2 /rGO composites can deliver ultrahigh specific capacity of 618 C g −1 at a current density of 3 A g −1 and maintain 276 C g −1 at 30 A g −1 in 6 M KOH electrolyte. Besides, the β-Ni(OH) 2 /rGO composite electrode exhibits outstanding cyclic stability. When tested at a current density of 10 A g −1 , high capacity retention ratio up to 90% can be achieved for the composite electrode after 2000 cycles. The outstanding cycling stability can be mainly attributed to rGO-encapsulating structure that effectively prevent the descent of electrical conductivity for the entirety of the electrode during the cycle processes. The ultrahigh specific capacity together with superb cycle performance make such composite a prospective candidate in capacitive energy storage field. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) porous structure that designed based on MnCo 2 O 4 decorated graphene was synthesized by a two-step method. The precursor was prepared of MnCo 2 O 4 by solid phase synthesis method, then in the hydrothermal reaction course, the graphene nanosheets as well as this precursor were self-assembled into a 3D interconnected network. The resultant composite materials present a higher specific capacitance (503 F g−1 at 1 A g−1 current density) and an excellent cycling stability. After 5000 charge/discharge cycles at a current density of 10 A g−1, 97.4% of the specific capacitance was retained. Thus, this material has a promising application potential for supercapacitor, at the same time, this synthetic method can also provide an idea for synthesizing composites based on 3D graphene in the future. • Three-dimensional composites of MnCo 2 O 4 and graphene were synthesized. • Three-dimensional graphene provides a porous skeleton. • The MnCo 2 O 4 /3DG electrode exhibits excellent electrochemical properties. • The excellent supercapacitor performance is attributed to the synergistic effect. [ABSTRACT FROM AUTHOR]