Nanostructured activated biomass carbon-cu2znsns4 kesterite material for high-performance supercapacitor

Abstract

This work introduces a novel Cu 2ZnSnS 4 (copper zinc tin sulfide [CZTS]) kesterite/coconut shell-derived biomass activated carbon(AC) nanocomposite material (CZTS 0.5:AC 0.5 ) for supercapacitor application. CZTS was prepared by microwave-assisted synthesisand combined with AC to produce CZTS0.5 :AC0.5 through mechanical milling and low-temperature annealing at 350°C. X-raydiffraction (XRD) and Raman spectroscopic analyses of CZTS0.5 :AC 0.5 nanocomposite revealed the formation of a multiphasesystem consisting of residual CZTS and secondary sulfides (zinc sulfide [ZnS], CuS, and SnS), which are embedded within a highlyconductive amorphous carbon matrix. High-resolution transmission electron microscopy (HRTEM) results indicate a reduction ofthe particle size from 55.7 nm (for CZTS) to 21.7 nm (for CZTS 0.5 :AC0.5 ) due to annealing. The nanostructurization of CZTS0.5 :AC0.5 created abundant electroactive sites that made the material an efficient charge storage system. Galvanostatic studies of AC//CZTS 0.5 :AC 0.5 in a three-electrode configuration produced a specific capacitance (Csp ) of 458.2 Fg−1 at 1 Ag−1 . Two-electrode AC//CZTS0.5 :AC 0.5 asymmetric supercapacitor device had a maximum energy density of 12.8 Wh kg−1 and a maximum power densityof 890.5 W kg−1 . The supercapacitor device exhibited excellent stability with a coulombic efficiency retention of 99.99% and acapacitance retention of 81.4% after 10,000 cycles. The results portray CZTS 0.5 :AC 0.5 nanocomposite material as a promising,sustainable electrode material for next-generation supercapacitors.