2 research outputs found
Synergistic effects in 3D honeycomb-like hematite nanoflakes/branched polypyrrole nanoleaves heterostructures as high-performance negative electrodes for asymmetric supercapacitors
Rational assembly of unique branched heterostructures is one of the
facile techniques to improve the electrochemical figure of merit of
materials. By taking advantages of hydrogen bubbles dynamic template,
hydrothermal method and electrochemical polymerization, branched
polypyrrole (PPy) nanoleaves decorated honeycomb-like hematite
nanoflakes (core-branch Fe2O3@PPy) are fabricated. X-ray diffraction,
X-ray photoelectron spectroscopy, scanning electron microscopy,
transmission electron microscopy (TEM), high-resolution TEM, and
scanning transmission electron microscopy in high angle annular dark
field mode with electron energy loss spectroscopy were combined to
elucidate the mechanisms underlying formation and morphogenesis
evolution of core-branch Fe2O3@PPy heterostructures. Benefiting from the
stability of honeycomb-like hematite nanoflakes and the high
conductivity of PPy nanoleaves, the resultant core-branch Fe2O3 PPy
exhibits an ultrahigh capacitance of 1167.8 F g(-1) at 1 A g(-1) in 0.5
M Na2SO4 aqueous solution. Moreover, the assembled bi-metal oxides
asymmetric supercapacitor (Fe2O3@PPy/ /MnO2) gives rise to a maximum
energy density of 42.4 W h kg(-1) and a maximum power density of 19.14
kW kg(-1) with an excellent cycling performance of 97.1\% retention
after 3000 cycles at 3 A g(-1). These performance features are superior
than previous reported iron oxide/hydroxides based supercapacitors,
offering an important guideline for future design of advanced
next-generation supercapacitors. (C) 2016 Elsevier Ltd. All rights
reserved