Premium
Graphite‐Aligned Ni/Ni(OH) 2 Nanowire‐Based Aqueous Asymmetric Supercapacitors Exhibiting Excellent Cycle Stability, High Rate Performance, and Wide Operation Voltage
Author(s) -
Pandey Rakesh K.,
Totake Yuichiro,
Soh Siowling,
Nakanishi Hideyuki
Publication year - 2019
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201903707
Subject(s) - supercapacitor , materials science , electrode , capacitance , nanowire , graphite , electrolyte , horizontal scan rate , aqueous solution , graphene , chemical engineering , nanotechnology , electrochemistry , layer (electronics) , optoelectronics , composite material , cyclic voltammetry , chemistry , organic chemistry , engineering
We present a new design for an asymmetric supercapacitor combining a vertically aligned Ni/Ni(OH) 2 nanowire array electrode and a graphite‐based electrode. The arrangement of these two electrodes in a sandwiched fashion allows the device to function at a high operating voltage window of 2.0 V in an aqueous electrolyte. A thin layer of Ni(OH) 2 can be readily formed on Ni nanowires (NiNWs) to yield a Ni/Ni(OH) 2 structure. The redox reaction of Ni(OH) 2 formed on the surface of NiNWs was crucial in achieving improved capacitance over this wide voltage window. The modification of the graphite electrode using graphene flakes was found to provide a more stable response at high current densities. The shape of the voltammogram can be retained up to high values and thus the device can operate at very rapid charge/discharge rates at an enhanced voltage window. Furthermore, the capacitance was found to be unchanged after 10000 continuous potential cycles.