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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]

Fe 3 O 4 nanospheres are synthesized by a solvothermal method with only one step under the assistance of surfactant. Fe 3 O 4 /C nanospheres are further fabricated by modifying Fe 3 O 4 nanospheres with glucose as carbon source. The crystalline structure and surface morphology are investigated by a combination of X-ray diffraction, Roman spectroscopy, transmission electron microscopy and scanning electron microscopy. The results suggest that cubic Fe 3 O 4 nanospheres are achieved, with a diameter around 200 nm. After the coating process, uniform carbon layer ~5 nm is formed on the surface of Fe 3 O 4 spheres. The electrochemical performances of prepared Fe 3 O 4 and Fe 3 O 4 /C nanospheres as anode materials for lithium-ion batteries are conducted via galvanostatic discharge/charge measurements and cyclic voltammetry. Under a current density of 100 mA g −1 , the Fe 3 O 4 /C nanospheres exhibit a delithiation capacity of 767.2 mAh g −1 over 100 cycles with excellent capacity retention of 98.2% and improved rate capacities, both of which are better than those of Fe 3 O 4 nanospheres. This work demonstrates that the prepared Fe 3 O 4 /C nanospheres can be a promising anode material for lithium ion batteries. [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]

Ni foam supported-NiCo 2 O 4 nanostructures with various morphologies are successfully prepared by a facile template-free method. The synthesis involves the electrodeposition of the bimetallic (Ni, Co) film on Ni foam support. The NiCo 2 O 4 nanostructures are formed by immersing the bimetallic film in an oxalic acid solution, followed by a calcination progress. The control over NiCo 2 O 4 nanostructures with different morphologies is achieved by adjusting the electrodeposition time and immersing time. The electrode is characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. H 2 O 2 electrooxidation and electroreduction in KOH solution on the NiCo 2 O 4 nanostructures are studied by cyclic voltammetry and chronoamperometry. Results show that NiCo 2 O 4 nanostructures exhibit high performance and superior stability for both H 2 O 2 electrooxidation and electroreduction, resulting from hierarchical porous structure inside their architectures. [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]