High performance of symmetric micro-supercapacitors based on silicon nanowires using N-methyl-N-propylpyrrolidinium bis (trifluoromethylsulfonyl)imide as electrolyte

This work describes the development and performance of a symmetric micro-supercapacitor made of nanostructured electrodes based on silicon nanowires (SiNWs) deposited using chemical vapor deposition (CVD) on silicon substrates. The performance of the SiNWs micro-supercapacitor employing an aprotic ionic liquid (N-methyl-N-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide) (PYR13TFSI) as an electrolyte was able to deliver a maximal power density of 182 mW cm(-2) and a specific energy of 190 mu J cm(-2) operating at a wide cell voltage of 4 V with a quasi-ideal capacitive behavior. The lifetime of the device exhibited a remarkable electrochemical stability retaining 75% of the initial capacitance after several million galvanostatic charge-discharge cycles at a high current density of 1 mA cm(-2). Furthermore, a coulombic efficiency of approximately 99% was obtained after galvanostatic cycling without structural degradation on the morphology of SiNWs. (C) 2014 Elsevier Ltd. All rights reserved.