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Ultrathin Two-Dimensional MnO2/Graphene Hybrid Nanostructures for High-Performance, Flexible Planar Supercapacitors
journal contribution
posted on 2013-05-08, 00:00 authored by Lele Peng, Xu Peng, Borui Liu, Changzheng Wu, Yi Xie, Guihua YuPlanar supercapacitors have recently
attracted much attention owing
to their unique and advantageous design for 2D nanomaterials based
energy storage devices. However, improving the electrochemical performance
of planar supercapacitors still remains a great challenge. Here we
report for the first time a novel, high-performance in-plane supercapacitor
based on hybrid nanostructures of quasi-2D ultrathin MnO2/graphene nanosheets. Specifically, the planar structures based on
the δ-MnO2 nanosheets integrated on graphene sheets
not only introduce more electrochemically active surfaces for absorption/desorption
of electrolyte ions, but also bring additional interfaces at the hybridized
interlayer areas to facilitate charge transport during charging/discharging
processes. The unique structural design for planar supercapacitors
enables great performance enhancements compared to graphene-only devices,
exhibiting high specific capacitances of 267 F/g at current density
of 0.2 A/g and 208 F/g at 10 A/g and excellent rate capability and
cycling stability with capacitance retention of 92% after 7000 charge/discharge
cycles. Moreover, the high planar malleability of planar supercapacitors
makes possible superior flexibility and robust cyclability, yielding
capacitance retention over 90% after 1000 times of folding/unfolding.
Ultrathin 2D nanomaterials represent a promising material platform
to realize highly flexible planar energy storage devices as the power
back-ups for stretchable/flexible electronic devices.