Facile synthesis of a phosphorus-doped graphene/nickel-cobalt sulfide nanocomposite derived from metal-organic framework as a high-performance electrode material for supercapacitors

Abstract

In this study, a hierarchical phosphorus-doped graphene/NiCo₂S₄ (PGNCS) nanocomposite was rationally engineered as a high-performance electrode material for supercapacitors via a sequential solvothermal–calcination–sulfidation strategy. The design integrates phosphorus-doped graphene (PG) with a bimetallic NiCo-based metal–organic framework (MOF) precursor, synergistically combining high electrical conductivity with abundant and accessible redox-active sites. Comprehensive characterizations-including XRD, BET, FT-IR, Raman, TEM, FE-SEM, and EDS mapping-confirm the successful formation of a porous, well-anchored architecture with uniformly distributed elements. Electrochemical measurements reveal outstanding performance, delivering a high specific capacitance of 1340 F g⁻¹ at 1 A g⁻¹ (GCD) and 767 F g⁻¹ at 5 mV s⁻¹ (CV), along with excellent cycling stability (⁓91% capacitance retention after 5000 cycles). The superior charge-storage capability originates from the synergistic interaction between the conductive PG scaffold and the highly active NiCo₂S₄ phase, which together facilitate rapid electron/ion transport and enhance Faradaic utilization. This work highlights PGNCS as a promising and rationally designed electrode material for next-generation energy storage devices.