Gold nanoparticles for power retention in electrochemical capacitors with KSCN-based aqueous electrolyte

Abstract

The paper reports the performance of the electrochemical capacitor operating with a nanoparticle-modified electrolyte. 7 mol L −1 KSCN aqueous solution, known as the electrolyte exhibiting redox activity originating from pseudohalide anion (SCN − ), has been enriched by gold nanoparticles at nanomolar concentration. The cycle life, specific energy of the device and power retention have been improved. The influence of nanoparticles concentration on the electrochemical capacitor performance has also been verified. All the nanoparticle-modified electrolytes display very high conductivity (∼370 mS cm −1 ); it is confirmed that the high energy density is retained at the whole range of applied current densities: 13.7 Wh kg −1 (at 1 A g −1 ) and 12.1 Wh kg −1 (at 20 A g −1 ). • Nanoparticles in the electrolytic solution improve power of capacitor. • The concentration of nanoparticles does not play any significant role. • The redox activity of thiocyanate remains unaffected by the presence of gold nanoparticles. • The impact of the nanoparticles is observed for redox-active electrolytes only.