Investigating Electrochemical Behavior of Cobalt Pentacyano(methlyaniline)ferrate(II) in Various Aqueous Electrolytes for Supercapacitor Application

Abstract

Electrochemical supercapacitors have excellent properties that can satisfy the demand of high power density, fast charging/discharging capability, and prolonged operational life but are restricted by limited energy density for large-scale development. Research on electrolytes, especially the redox active electrolyte, which is crucial for significantly enhancing specific capacity has received far less attention over the past decade. Prussian blue analogues playa vital role as electrode material in supercapacitor applications due to their morphology and three-dimensional open channel structure. Herein, a facile coprecipitation approach was adopted to fabricate cobalt pentacyano(methylaniline)ferrate(II) with enhanced electrochemical performance and is characterized via different techniques that include; X-ray diffraction analysis (XRD), fourier transform infrared spectroscopy (FT -IR), scanning electron microscopy coupled energy dispersive X-ray (SEM-EDX). An electrolyte-based study was carried out to evaluate the electrochemical perfonnance and it exhibited excellent specific capacity of 390 mAh g-l, 233 mAh g-l, 175 mAh g-l, 83 mAh g-l in 3M KOH, 1M NaOH, 1M LiOR, and 1M KN03 with specific capacity retention of88 %, 88.2 %, 86.5 % and 87.8 % over 1000 cycles, respectively. Furthemlore, solid-state supercapacitors were fabricated by using polyvinyl alcohol (PV A)/KOH gel as a solid electrolyte. Symmetrical supercapacitors exhibited a specific capacity of24 mAh g-I at the current density of 1 A g-I with an energy density of 24 Wh Kg-I and power density of 1960 W Kg-I. Moreover, a hybrid asymmetric solid-state supercapacitor was also fabricated in the same electrolyte that demonstrated specific capacity of 55 mAh g-l with an energy density of71 Wh Kg-1 and power density of2560 W Kg-1 at the current density of 1 A g- l. Conclusively, the utilization of Prussian blue analogues in energy storage applications holds great promise because of their excellent electrochemical performance, improved chemical resistance, ease of synthesis, and cost-effectiveness.