Sparse MnO2 nanowires clusters for high-performance supercapacitors

Abstract

MnO2 nanowires clusters are electrodeposited onto Ni foam by a cyclic voltammetric technique. MnO2 nanowires, about 20nm in diameter and up to 200nm in length, present a sparse grass clusters structure. As cathode material for supercapacitors, MnO2 nanowires clusters exhibit superior pseudocapacitance performances with high specific capacitances (1080Fg−1 at 4Ag−1 and 415Fg−1 at 30Ag−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.