Hollow architectures of CoNi2S4/NiS2 with boosted performance for supercapacitors

Abstract

Hollow architectures have great prospects in supercapacitors due to their rich active surface area, good structural stability and convenient transmission channels for ions/electrons. Herein, we present a self-engaged template process to prepare hybrid CoNi₂S₄/NiS₂ hollow architectures. Ni–Co glycerate solid spheres are used as templates and transformed to CoNi₂S₄/NiS₂ via a sulfidation procedure. The supercapacitor’s performance evaluation unveils that these CoNi₂S₄/NiS₂ hollow architectures manifest a high capacitance of 1309.2 F g⁻¹ at 4.0 A g⁻¹ and remarkable cyclability with 1147.6 F g⁻¹ retention (only 4.2% decay) for 5000 cycles at 6.0 A g⁻¹. Furthermore, a two-electrode cell assembly of the CoNi₂S₄/NiS₂ and activated carbon, displays an energy density of 47.5 W h kg⁻¹ at 3301 W kg⁻¹ and impressively durable cycle life. These results provide a simple avenue to design an efficient electrode material for supercapacitors based on metal sulfides.