▎ 摘　　要

A novel MnO2 nanosheets/graphene nanosheets/carboxylic multi-walled carbon nanotubes (MONS/GNS/cMWCNT) ternary composite film was fabricated through a filtration-directed self-assembly method. The Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images showed the porous sandwiched structure of MONS/GNS/cMWCNT with GNS providing a conductive substrate and cMWCNT functioning as a vertical electron pathway. The X-ray diffraction (XRD) and Raman spectra further confirmed that the introduction of GNS and cMWCNT restricted the serious aggregation of MONS, resulting in a higher specific area (691 m(2)g(-1)). As a result, the MONS/GNS/cMWCNT composite film exhibited higher specific capacitance (248 Fg(-1) at 1 Ag-1 in 1 M Na2SO4), better rate performance (66.9% capacitance retention from 0.2 to 10 Ag-1) and cycling stability (86.5% retention after 3000 cycles) compared with those of pure dried MnO2 nanosheets. (C) 2014 Elsevier Ltd. All rights reserved.