Phosphate functionalized CoS nanoparticles coupled with Fe2O3 nanocrystals decorated on N,S co-doped porous carbon spheres for advanced hybrid supercapacitors

Abstract

Devising electrode materials with novel configurations and unique properties is a feasible strategy to boost the electrochemical properties of hybrid supercapacitors. This research demonstrates an effective two-step strategy to construct N,S co-doped porous carbon (NSC) sphere supported CoS nanoparticles with phosphate functionalization (P-NSC/CoS). Benefiting from the active multi-components, the electrochemical features of CoS can be remarkably modulated after the NSC and phosphate modifications. As the cathode material for the supercapacitor, the acquired P-NSC/CoS composite delivers a splendid capacity of 436.5 C g⁻¹ at 1 A g⁻¹ and a superb cycling property of 91.5% after 10 000 cycles at 10 A g⁻¹ in 6 M KOH. Furthermore, the Fe₂O₃ nanocrystals with ultrafine size are in situ deposited on NSC via a solvothermal-calcination process. The NSC/Fe₂O₃ composite presents a sizeable capacitance of 433 F g⁻¹ at 1 A g⁻¹ with 100.6% capacitance retention after 10 000 cycles. More significantly, it is inspiring that the assembled P-NSC/CoS//NSC/Fe₂O₃ hybrid supercapacitor delivers an energy density of up to 64.3 W h kg⁻¹ at 873.6 W kg⁻¹ and a splendid cycling stability of 94.2% after 10 000 cycles at 5 A g⁻¹ in 6 M KOH. The appreciable data demonstrate that the prepared advanced electrode materials and the hybrid supercapacitor display excellent application prospects in energy storage.