title: Facile synthesis and strongly microstructure-dependent electrochemical properties of graphene/manganese dioxide composites for supercapacitors.
abstract: Graphene has attracted much attention since it was firstly stripped from graphite by two physicists in 2004, and the supercapacitor based on graphene has obtained wide attention and much investment as well. For practical applications of graphene-based supercapacitors, however, there are still many challenges to solve, for instance, to simplify the technological process, to lower the fabrication cost, and to improve the electrochemical performance. In this work, graphene/MnO2 composites are prepared by a microwave sintering method, and we report here a relatively simple method for the supercapacitor packaging, i.e., dipping Ni-foam into a graphene/MnO2 composite solution directly for a period of time to coat the active material on a current collector. It is found that the microwave reaction time has a significant effect on the microstructure of graphene/MnO2 composites, and consequently, the electrochemical properties of the supercapacitors based on graphene/MnO2 composites are strongly microstructure dependent. An appropriately longer microwave reaction time, namely, 15 min, facilitates a very dense and homogeneous microstructure of the graphene/MnO2 composites, and thus, excellent electrochemical performance is achieved in the supercapacitor device, including a high specific capacitance of 296 F/g and a high capacitance retention of 93% after 3,000 times of charging/discharging cycles.
  81.05.ue; 78.67.Sc; 88.80.fh.
authors.affiliation: Department of Materials Science, Sichuan University, Chengdu 610064, People's Republic of China.
authors.forename: Caiyun
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Materials Science, Sichuan University, Chengdu 610064, People's Republic of China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Materials Science, Sichuan University, Chengdu 610064, People's Republic of China.
authors.forename: Zhongxing
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Materials Science, Sichuan University, Chengdu 610064, People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Sun
authors.affiliation: Department of Materials Science, Sichuan University, Chengdu 610064, People's Republic of China.
authors.forename: Yinjuan
authors.initials: Y
authors.lastname: Ren
authors.affiliation: Department of Materials Science, Sichuan University, Chengdu 610064, People's Republic of China.
authors.forename: Jiliang
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Department of Materials Science, Sichuan University, Chengdu 610064, People's Republic of China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Department of Materials Science, Sichuan University, Chengdu 610064, People's Republic of China.
authors.forename: Dingquan
authors.initials: D
authors.lastname: Xiao
keywords: Composite; Electrochemical properties; Graphene; Manganese dioxide; Microstructure; Supercapacitors