Fabrication of biowaste derived carbon-carbon based electrodes for high-performance supercapacitor applications

Abstract

The porous carbon is synthesised by chemical activation using cork dust bio-waste as carbon source and the electrochemical performance of the resulting carbon material is tested in even and uneven weight configuration using a two-electrode system. The obtained cork dust derived activated carbon (CDAC) shown a unique honeycomb structured morphology as confirmed by morphological analysis. X-ray diffraction (XRD) and Raman characterisation revealed the graphitic nature of the CDAC. Furthermore, the porous CDAC exhibited high specific surface area (1707 m2/g) and large pore volume (2.4 cc/g) with an average pore size of 4 nm. Even weight supercapacitor cell (SC) (positive and negative electrode with the same weight) and uneven weight SC cell (weight ratio of positive/negative electrodes:1.2) are assembled and tested in 1M TEABF4/AN. Uneven weight SC cell delivers the highest specific capacitance value of 107 F/g at a current density of 1 A/g. The uneven weight device shows promising cyclic stability without significant changes in capacitance values after 10000 and 5000 charge-discharge cycles at the potential window of 3 V and 3.2 V, respectively. On the contrary, a less specific capacitance (87 F/g at a current density of 1 A/g) observed for the even weight SC cell though high-capacity retention is realised under the same experimental conditions. The enhanced supercapacitor performance of uneven weight configuration SC cell is attributed to the weight balancing of the electrode, high graphitic nature, and unique pore size distribution with interconnected morphology of CDAC.