Wide-voltage-window silicon nanowire electrodes for micro-supercapacitors via electrochemical surface oxidation in ionic liquid electrolyte

The potential of silicon nanowires (SiNWs) as electrode material for large-voltage window micro-supercapacitors has been investigated. An ionic liquid electrolyte (EMI-TFSI) has been used in order to prevent the previously reported etching of silicon electrodes. Electrochemical oxidation of silicon surface at high anodic potentials leads to an extended operating voltage range (up to 4 V) and slightly enhanced specific capacitance of silicon electrodes. The ability of SiNW electrodes to operate at high frequency was demonstrated and a promising specific power of 472 mu W cm(-2) was obtained. (C) 2014 Elsevier B.V. All rights reserved.