Electrochemical Kinetics and Energy Storage Performance of 3D Hierarchical CuFeS 2 @rGO Micro-flower Electrodes

Abstract

Among various candidates, hierarchical nanostructured composites integrating transition metal chalcogenides with conductive carbon frameworks have emerged as promising platforms due to their enhanced electrochemical activity and rapid charge transport properties. A threedimensional hierarchical micro-flower architecture of copper-iron sulphide (CuFeS 2 ) integrated with reduced graphene oxide (rGO) is successfully developed and evaluated as a high-performance pseudocapacitive electrode material. The CuFeS 2 @rGO composite is synthesized via a facile two-step hydrothermal approach, yielding a porous and interconnected structure that facilitates efficient electrolyte accessibility and charge transport. Electrochemical investigations conducted in 1 M aqueous LiOH within a three-electrode configuration reveal that the composite exhibits superior charge storage characteristics, arising from the synergistic interplay between surface-controlled pseudocapacitance of CuFeS 2 and electric double-layer capacitance contributed by rGO. Notably, the CuFeS 2 @rGO electrode delivers a high specific capacitance of ~1160 F g -1 at 1 A g -1 , significantly outperforming pristine CuFeS 2 (308 F g -1 ).In addition, the composite demonstrates excellent cycling stability, indicating its robustness for long-term operation. A symmetric supercapacitor device assembled using CuFeS 2 @rGO electrodes exhibits remarkable energy and power densities, along with outstanding cyclic durability, retaining 96.03% of its initial capacitance after 10,000 charge-discharge cycles.These findings highlight the strong potential of earth-abundant CuFeS 2 -based hybrid architectures for next-generation high-performance supercapacitor applications.