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In this work, for the first time we are reporting the development of a kind of high rate and long cycle life electrode composed of nickel cobalt manganese ternary carbonate hydroxide (NiCoMn-CH) ultrathin nanoflakes coated on Co-CH nanowire arrays (NWAs), which are directly generated on a nickel foam (NF) support. The hierarchical heterostructures are synthesized via a scalable two step solvothermal strategy without any adscititious surfactant and binder. The smart combination of Co-CH and NiCoMn-CH nanostructures in the nanowire arrays shows significant synergistic effect on the enhancement of the electrochemical performance of the as-fabricated supercapacitors. The as-obtained electrode exhibits excellent conductivity and high specific surface area, resulting in an unprecedented high specific capacitance (up to 3224 F g−1 at 1 A g−1 in a three-electrode system) and an ultralong cycling stability (92.4% retention after 6000 successive charge–discharge cycles 5 A g−1). Meanwhile, an asymmetric supercapacitor device assembled of the Co-CH@NiCoMn-CH hierarchical nanostructures as positive electrode and activated carbon (AC) as negative electrode delivers good energy density of 20.31 W h kg−1 at the power density of 748.46 W kg−1 in the operation window 0–1.5 V. This methodology could be generalized to the design of other novel structured nanomaterials for energy storage devices and other applications. [ABSTRACT FROM AUTHOR]

Trimetallic sulfide microspheres with flower morphology prepared based on novel bimetallic MOF via sequential ion exchange processes exhibit promising energy storage properties. Rational design of electrical active materials with high performance for energy storage and conversion is of great significance. Herein, Cu(NiCo) 2 S 4 /Ni 3 S 4 , a three-dimensional (3D) hierarchical hollow heterostructured electrode material, is designed by etching the well-defined bimetal organic framework (MOF) via sequential in-situ ion-exchange processes. This trimetallic sulfides with unique structure provide large surface area, hierarchical pore distribution and enhanced electrical conductivity, can enrich the active sites for redox reactions, facilitate electrolyte penetration and rapid charge transfer kinetics. As a result, the Cu(NiCo) 2 S 4 /Ni 3 S 4 electrode exhibits a high specific capacitance of 1320 F/g at 1 A/g and excellent rate performance (only 15% of capacitance is attenuated when the current density is increased by 20 times). Furthermore, a fabricated hybrid supercapacitor of Cu(NiCo) 2 S 4 /Ni 3 S 4 /AC can deliver a maximum energy density of 40.8 Wh/kg, remarkable power density of 7859.2 W/kg and superior cycling stability (85% retention of capacitance after 5000 cycles), demonstrating great potential for practical applications in energy storage and conversion devices. [ABSTRACT FROM AUTHOR]

Herein, we designed and prepared nickel metal-organic framework microspheres anchored directly on reduced graphene oxide (Ni-MOF/rGO) by a facile hydrothermal and successive calcining process. The electrode for Ni-MOF/rGO composite annealed at an optimized temperature of 300 °C (Ni-MOF/rGO-300) shows desired conductivity, good cycling stability and high ion-accessible surface area, leading to an ultrahigh specific capacitance of 954 F g−1 at a current density of 1 A g−1 and a remarkable rate capability of 80.25% at 5 A g−1. Meanwhile, the assembled Ni-MOF/rGO-300//activated carbon asymmetric supercapacitor (ASC) shows a favorable energy density up to 17.13 Wh kg−1 at a power density of 750 W kg−1 in the potential window of 0–1.5 V. Moreover, the capacitance retention can still maintain 81.63% after 4000 cycles at a high current density of 5 A g−1. The excellent electrochemical properties can be credited to the synergistic effects between the unique structures of Ni-MOF and rGO, which makes the Ni-MOF/rGO composite a potential electrode material for high performance supercapacitors. [ABSTRACT FROM AUTHOR]

The hollow and spinous NiCo 2 S 4 nanotubes were designed and prepared through hydrothermal sulfurization reaction using the degummed natural cocoon silk as a template. Recently, ternary cobalt nickel sulfide, performing as the promising electrode material for supercapacitors has obtained great interests. Herein, the hollow and spinous NiCo 2 S 4 nanotubes are designed and prepared through a simple hydrothermal reaction using the natural silk as the template. The spinous Ni-Co precursors are grown on the natural silk through a facile hydrothermal strategy and the hollow structure is obtained by decomposing the silk via hydrothermal sulfurization. After the calcination treatment, the hollow and spinous NiCo 2 S 4 nanotubes are applied as the electrode material and exhibit better electrochemical performance than the solely vulcanized samples. In addition, owing to the unique hollow and spinous structure of NiCo 2 S 4 nanotubes, the supercapacitor electrode material shows good specific capacitance (630 F g−1 at 1 A g−1), low internal resistance R s (0.68 Ω) and high capacitance retention (91% after 3000 cycles) at 10 A g−1. Furthermore, an all-solid-state asymmetric supercapacitor is self-assembled with the SC400 composite and exhibits an energy density of 52.34 Wh kg−1 at the power density of 2206.37 W kg−1. Additionally, a blue LED indicator can be powered by connecting two ASCs in series. The prepared hollow and spinous NiCo 2 S 4 nanotubes with excellent electrochemical properties can envision promising applications in energy storage devices and nanotechnology. [ABSTRACT FROM AUTHOR]