Hierarchically porous metallic silver monoliths: facile synthesis, characterization and its evaluation as an electrode material for supercapacitors

A simple method for exploiting soft template Pluronic P123 and silica nanoparticles for the fabrication of porous silver (pAg) monoliths via modified sol gel route is reported. The pAg monoliths were characterized using FTIR, TGA, XRD, FESEM-EDX and BET techniques. The Brunauer–Emmett–Teller (BET) and field emission scanning electron microscopic techniques (FESEM) were used to study the surface area and porous characteristics. Further, the electrochemical capacitor properties of pAg monoliths were studied using cyclic voltammetry, electrochemical impedance spectroscopy and Galvanostatic charge/discharge techniques. The total capacitive characteristics of pAg monoliths are attributed to the pseudocapacitive characteristics which is due to the redox behavior of Ag/Ag⁺ and electrochemical double layer capacitance due to its porous nature. Electrochemical measurements show that the maximum specific capacitance, power density and the energy density obtained for pseudocapacitor using pAg modified glassy carbon electrode (pAg/GCE) were 224.0 Fg⁻¹, 17.6 kW kg⁻¹and 31.0 Wh kg⁻¹, respectively at the current density of 0.5 Ag⁻¹. The fabricated pAg modified glassy carbon electrode (pAg/GCE) exhibited excellent life cycle with 91.3 % of the initial specific capacitance retained after 1,000 cycles. The results suggest that this porous material is a promising supercapacitor electrode material.