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Highlights: [•] β-Ni(OH)2 was modified via a template-free method by using different nickel salt. [•] The effects on the morphology and electrochemical behaviors were investigated. [•] The β-Ni(OH)2–SO4 2−/Ni-foam electrode displays 1025.3Fg−1 at 1.0Ag−1. [ABSTRACT FROM AUTHOR]

In this work, Co(OH) 2 buds direct growth on Ni foam (Co(OH) 2 buds/Ni foam) is prepared via a hydrothermal method. Their structure and morphologies are characterized by using X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy. Result shows that the Co(OH) 2 buds are assembled by several nanorods and uniformly covered on the surface of Ni foam. Due to its unique structure, the Co(OH) 2 buds/Ni foam electrode shows high capacitive performance and long cycle life. The specific capacitance of Co(OH) 2 buds/Ni foam is as high as 2041 F g −1 at a current density of 3 mA cm −2 in 6 M KOH electrolyte, and 811 F g −1 even at a high current density of 60 mA cm −2 . The capacitance of the Co(OH) 2 buds/Ni foam electrode remained 72.4% after 1000 cycles at 18 mA cm −2 . An asymmetric supercapacitor was successfully assembled, in which Co(OH) 2 buds/Ni foam and AC used as positive and negative electrode, respectively. The energy density of the AC//Co(OH) 2 buds/Ni foam supercapacitor reaches to 20.3 W h kg −1 at a power density of 90.6 W kg −1 . Our result shows that the Co(OH) 2 materials are promising candidate for electrochemical energy applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] Fe2O3 sheets have been synthesized on nickel foam by a simple template-free growth process and heat treatment. [•] The Fe2O3 electrode exhibits a specific capacitance of 147Fg−1 at 0.36Ag−1 and 98Fg−1 at 3.6Ag−1. [•] The as-prepared Fe2O3 electrode presents a wider potential window of 1.0V. [Copyright &y& Elsevier]

Highlights: [•] Cd(OH)2 nanowires was directly grown on nickel foam via a simple template-free method. [•] Cd(OH)2 nanowires exhibits a high specific capacitance of is 1164.8Fg−1 at 1Ag−1 in 6moldm−3 KOH solution. [•] The as-prepared Cd(OH)2 nanowires has potential applications in electrochemical capacitors. [Copyright &y& Elsevier]