Enhancing Electrochemical Properties of Walnut ShellActivated Carbon with Embedded MnO Clusters forSupercapacitor Applications

Abstract

Activated carbon (AC) materials from renewable sources arewidely used in electrochemical applications due to their well-known high surface area. However, their application aselectrode material in double-layer electrochemical devices maybe limited due to their relatively low electrical conductivity andlightweight. To overcome these limitations, the incorporation ofpseudocapacitance metal oxide nanoparticles is an optimumapproach. These nanoparticles can provide a second energystorage mechanism to the composite, mitigating the loss ofsurface area associated with their incorporation. As a result, thecomposite material is endowed with increased conductivity andhigher density, making it more suitable for practical implemen-tation in real devices. In this study, we have incorporated a finedispersion of 1 % of MnO clusters into a highly porous activatedcarbon synthesized from walnut shells (WAC). The high-resolution electron microscopy studies, combined with theirrelated analytical techniques, allow us to determine thepresence of the cluster within the matrix carbon precisely. Theresulting MnO@WAC composite demonstrated significantlyimproved capacitive behavior compared with the WAC material,with increased volumetric capacitance and higher chargeretention at higher current densities. The composite‘s electro-chemical performance suggests its potential as a promisingelectrode material for supercapacitors, addressing drawbacksassociated with traditional AC materials.