Anticorrosive performance of green deep eutectic solvent for electrochemical capacitor

Reline Deep Eutectic Solvent (DES) is widely recognized as a novel and green electrolyte for industrial applications due to its low cost and tolerance to moisture. It has received significant attention, however, its application in the energy storage system is still in infancy. Generally, aqueous-based electrochemical capacitors (ECs) present an ideal energy storage technology because of several advantages. Yet, high corrosion of the current collector limits their cyclability. Novel Reline DES electrolyte is studied and its anticorrosive electrochemical performance is evaluated in carbon-based ECs using stainless steel current collector (316L). Our findings show that Reline electrolyte and its water mixture display a strong inhibiting corrosion effect for 316L. Furthermore, a few aqueous electrolytes are studied to confirm the effectiveness of Reline DES as a green and anti-corrosive electrolyte for EC. Floating protocol is applied to monitor the stability of the EC performance in Reline and aqueous electrolytes. The devices using pure Reline and its water mixture exhibit higher electrochemical stability with good capacitive performance compared to 1 M Li2SO4 and 1 M KOH based ECs. The study may pave the way to practical Reline DES-based ECs for sustainable, highly stable, environmentally friendly and cost-effective energy storage systems in the future.