Novel hybrid micro-supercapacitor based on conducting polymer coated silicon nanowires for electrochemical energy storage

Abstract

The development of a novel hybrid symmetric micro-supercapacitor based on poly(3,4-ethylenedioxythiophene) coated silicon nanowires using an ionic liquid (N-methyl-N-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide) as an electrolyte has been demonstrated. The hybrid supercapacitor device was able to deliver a specific energy of 10 W h kg⁻¹ and a maximal power density of 85 kW kg⁻¹ at a cell voltage of 1.5 V. The hybrid device exhibited long lifetime and an outstanding electrochemical stability retaining 80% of the initial capacitance after thousands of galvanostatic charge–discharge cycles at a high current density of 1 mA cm⁻². The improvement of the capacitive properties compared with the bare SiNWs was attributed to the pseudo-capacitive behavior induced by the conducting polymer coating.