Understanding the energy storage mechanisms of poly(3,4-ethylenedioxythiophene)-coated silicon nanowires by electrochemical quartz crystal microbalance

Abstract

The capacitive properties of electrodes elaborated from the electrochemical deposition of poly(3,4-ethylenedioxythiophene) (PEDOT) coatings onto chemical vapor deposition (CVD)-grown silicon nanowires (SiNWs) were investigated for supercapacitor applications. A high areal capacitance value of 17 mF cm−2 (50 F g−1) was obtained at a scan rate of 100 mV s−1 in a 3-electrode cell configuration. Furthermore, this 3D hybrid nanostructure was analyzed by electrochemical quartz crystal microbalance (EQCM) to correlate the interfacial ionic exchange mechanisms to their electrochemical performance. It was demonstrated that both anions (BF4−) and cations (TBA+) were simultaneously involved in the charge compensation during the oxidation-reduction scans of cyclic voltammetry measurements.