title: Direct Reduction of Graphene Oxide by Ni Foam as a High-Capacitance Supercapacitor Electrode.
abstract: Three dimensional reduced graphene oxide (RGO)/Ni foam composites are prepared by a facile approach without using harmful reducing agents. Graphene oxide is reduced by Ni foam directly in its aqueous suspension at pH 2 at room temperature, and the resultant RGO sheets simultaneously assemble around the pillars of the Ni foam. The RGO/Ni foam composite is used as a binder-free supercapacitor electrode and exhibits high electrochemical properties. Its areal capacitance is easily tuned by varying the reduction time for different RGO loadings. When the reduction time increases from 3 to 15 days, the areal capacitance of the composite increases from 26.0 to 136.8 mF cm(-2) at 0.5 mA cm(-2). Temperature is proven to be a key factor in influencing the reduction efficiency. The composite prepared by 5 h reduction at 70 °C exhibits even better electrochemical properties than its counterpart prepared by 15 day reduction at ambient temperature. The 5 h RGO/Ni foam composite shows an areal capacitance of 206.7 mF cm(-2) at 0.5 mA cm(-2) and good rate performance and cycling stability with areal capacitance retention of 97.4% after 10000 cycles at 3 mA cm(-2). Further extending the reduction time to 9 h at 70 °C, the composite shows a high areal capacitance of 323 mF cm(-2) at 0.5 mA cm(-2). Moreover, the good rate performance and cycling stability are still maintained.
authors.affiliation: State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology , Beijing 100029, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology , Beijing 100029, China.
authors.forename: Enwei
authors.initials: E
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology , Beijing 100029, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology , Beijing 100029, China.
authors.forename: Yunhua
authors.initials: Y
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology , Beijing 100029, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology , Beijing 100029, China.
authors.forename: Zhong-Zhen
authors.initials: ZZ
authors.lastname: Yu
keywords: Ni foam; binder-free; electrochemical performance; graphene oxide; supercapacitor electrode