Thin metal film on porous carbon as a medium for electrochemical energy storage

Abstract Processing of suitable materials as sustainable, eco-friendly, and cheaper energy storing electrodes offer significant challenges to overcome the current thresholds. In this work, we demonstrate development of a thin metallic (cobalt, in this case) film over biowaste-resourced porous carbon (PC) as a high performing supercapacitor electrode in aqueous alkaline electrolyte and lithium ion capacitor (LIC) configuration in an ionic electrolyte. The hierarchical structure thus developed are characterized for their chemical (crystal structure, surface chemical configuration), surface (morphology, surface area, and porosity) and electrochemical (voltammetric, galvanostatic and impedance spectroscopic) properties. The cobalt coating favourably modified the surface of PC such that the charge storability is enhanced. An optimized metal concentration (10% Co over PC) delivers over 100% increase in the charge storability with 20% increase in the potential window than the pure PC electrode. The LIC and the aqueous alkaline supercapacitor deliver impressive energy and power densities.