title: Controllable in situ synthesis of epsilon manganese dioxide hollow structure/RGO nanocomposites for high-performance supercapacitors.
abstract: Well-organized epsilon-MnO2 hollow spheres/reduced graphene oxide (MnO2HS/RGO) composites have been successfully constructed via a facile and one-pot synthetic route. The ε-MnO2 hollow spheres with the diameter of ∼500 nm were grown in situ with homogeneous distribution on both sides of graphene oxide (GO) sheets in aqueous suspensions. The formation mechanism of the MnO2HS/RGO composites has been systematically investigated, and a high specific capacitance and good cycling capability were achieved on using the composites as supercapacitors. The galvanostatic charge/discharge curves show a specific capacitance of 471.5 F g(-1) at 0.8 A g(-1). The hollow structures of ε-MnO2 and the crumpled RGO sheets can enhance the electroactive surface area and improve the electrical conductivity, thus further facilitating the charge transport. The MnO2HS/RGO composite exhibits a high capacitance of 272 F g(-1) at 3 A g(-1) (92% retention) even after 1000 cycles. The prominent electrochemical performance might be attributed to the combination of the pseudo-capacitance of the MnO2 nanospheres with a hollow structure and to the good electrical conductivity of the RGO sheets. This work explores a new concept in designing metal oxides/RGO composites as electrode materials.
authors.affiliation: Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hong Kong, China. jikang.yuan@polyu.edu.hk.
authors.forename: Mei
authors.initials: M
authors.lastname: Lin
authors.affiliation: Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hong Kong, China. jikang.yuan@polyu.edu.hk.
authors.forename: Bolei
authors.initials: B
authors.lastname: Chen
authors.affiliation: Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hong Kong, China. jikang.yuan@polyu.edu.hk.
authors.forename: Xiao
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hong Kong, China. jikang.yuan@polyu.edu.hk.
authors.forename: Jiasheng
authors.initials: J
authors.lastname: Qian
authors.affiliation: Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hong Kong, China. jikang.yuan@polyu.edu.hk.
authors.forename: Linfeng
authors.initials: L
authors.lastname: Fei
authors.affiliation: Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hong Kong, China. jikang.yuan@polyu.edu.hk.
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.affiliation: Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hong Kong, China. jikang.yuan@polyu.edu.hk.
authors.forename: Lai Wa Helen
authors.initials: LW
authors.lastname: Chan
authors.affiliation: Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hong Kong, China. jikang.yuan@polyu.edu.hk.
authors.forename: Jikang
authors.initials: J
authors.lastname: Yuan