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Graphical abstract The seamless integrated C@NiMn-OH-Ni 3 S 2/ Ni foam advanced electrode with hierarchical structures is successfully synthesized for high-performance supercapacitors. Highlights • A novel hierarchical nanostructure C@NiMn-OH-Ni 3 S 2 /Ni foam integrated advanced electrode was constructed. • The as-prepared hybrid advanced electrode exhibited extraordinary capacitance characteristics. • An asymmetric supercapacitor (ASC) was successfully constructed to power the LED. • The ASC devices achieves high energy density and superior cycling performance. Abstract Rational design and fabrication of hierarchical structures consisting of multiple components with distinctive features in situ grown on porous Ni foam skeleton is feasible and effective to boost the electrochemical properties of supercapacitors. Herein, a novel hierarchical C@NiMn-OH-Ni 3 S 2 /Ni foam hybrid integrated advanced electrode was successfully fabricated via a facile three-step hydrothermal method, involving two hydrothermal reaction to grow NiMn-OH nanoflakes onto Ni 3 S 2 thin film in situ grown on conductive Ni foam and then a glucose carbonization process to cover carbon on NiMn-OH. Benefiting from the synergistic effect of Ni 3 S 2 and NiMn-OH with enhancement of both the electrical and the ionic conductivity, the as-obtained C@NiMn-OH-Ni 3 S 2 /Ni foam exhibited an excellent specific capacitance of 2521 F g−1 at a current density of 1 A g−1, and cycle stability increased from 82.4% to 92.1% after coating the carbon layer. Furthermore, an aqueous asymmetric supercapacitor was successfully assembled using C@NiMn-OH-Ni 3 S 2 /Ni foam as the positive electrode and activated carbon (AC) as the negative electrode (C@NiMn-OH-Ni 3 S 2 /Ni foam//AC), such device delivers a maximum energy density of 45.3 Wh kg−1 at the power density of 1275 W kg−1, and a superior cycling stability (∼94.6% capacity retention after 10,000 cycles). [ABSTRACT FROM AUTHOR]

In order to reduce the cost of electrode active material, a three-dimensional (3D) sponge-like Co/Co(OH) 2 nanocomposite was synthesized by a simple NaBH 4 reduction method at room temperature. For supercapacitor application, the Co/Co(OH) 2 nanocomposite exhibits an excellent specific capacity of 1048 F g −1 at a current density of 1 A g −1 in a potential range of 0–0.45 V from the charge/discharge test, and the retention of capacitance is 70.6% after 5000 cycles. The sponge-like Co/Co(OH) 2 nanocomposite displays high supercapacitor performance, excellent rate capability and cycling stability. [ABSTRACT FROM AUTHOR]

The design and fabrication of efficientand inexpensive electrodesfor use in the oxygen evolution reaction (OER) is essential for energy-conversiontechnologies. In this study, high OER performance is achieved usingnovel hierarchical ZnxCo3–xO4nanostructures constructed with smallsecondary nanoneedles grown on primary rhombus-shaped pillar arrays.The nanostructures have large roughness factor, high porosity, andhigh active-site density. Only a small overpotential of ∼0.32V is needed for a current density of 10 mA/cm2with a Tafelslope of 51 mV/decade. The nanostructures are also found to performsignificantly better than pure Co3O4and a commercialIr/C catalyst and to perform similarly to the best OER catalysts thathave been reported for alkaline media. These merits combined withthe satisfactory stability of the nanostructures indicate that theyare promising electrodes for water oxidation. [ABSTRACT FROM AUTHOR]