Sparse MnO2 nanowires clusters for high-performance supercapacitors

MnO2 nanowires clusters are electrodeposited onto Ni foam by a cyclic voltammetric technique. MnO2 nanowires, about 20 nm in diameter and up to 200 nm in length, present a sparse grass clusters structure. As cathode material for supercapacitors, MnO2 nanowires clusters exhibit superior pseudocapacitance performances with high specific capacitances (1080 Fg(-1) at 4 Ag-1 and 415 Fg(-1) at 30 Ag-1) as well as excellent large-current cycling stability, making it suitable for high-performance supercapacitor application. The improved pseudocapacitance performances are attributed to small size, large surface area and high dispersion degree of MnO2 NWs, as well as 3-Dimension structure of Ni foam, which provide faster ion and electron transfer, larger reaction surface area, higher electrochemical activity, leading to faster reaction kinetics and higher material utilization ratio. (C) 2012 Elsevier B.V. All rights reserved.