超级电容器
材料科学
电容
电极
石墨烯
准固态
功率密度
复合材料
扫描电子显微镜
化学工程
纳米技术
功率(物理)
电解质
色素敏化染料
量子力学
物理
工程类
物理化学
化学
作者
Guoping Xiong,Pingge He,Dini Wang,Qiangqiang Zhang,Tengfei Chen,Timothy S. Fisher
标识
DOI:10.1002/adfm.201600879
摘要
A hierarchical structure consisting of Ni–Co hydroxide nanopetals (NCHPs) grown on a thin free‐standing graphene petal foam (GPF) has been designed and fabricated by a two‐step process for pseudocapacitive electrode applications. The mechanical behavior of GPFs has been, for the first time to our knowledge, quantitatively measured from in situ scanning electron microscope characterization of the petal foams during in‐plane compression and bending processes. The Young's modulus of a typical GPF is 3.42 GPa, indicating its outstanding mechanical robustness as a nanotemplate. The GPF/NCHP electrodes exhibit volumetric capacitances as high as 765 F cm −3 , equivalent to an areal capacitance of 15.3 F cm −2 and high rate capability. To assess practical functionality, two‐terminal asymmetric solid‐state supercapacitors with 3D GPF/NCHPs as positive electrodes are fabricated and shown to exhibit outstanding energy and power densities, with maximum average energy density of ≈10 mWh cm −3 and maximum power density of ≈3 W cm −3 , high rate capability (a capacitance retention of ≈60% at 100 mA cm −2 ), and excellent long‐term cyclic stability (full capacitance retention over 15 000 cycles).
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