Synthesis of multi-dimensional nanostructured Co(OH)F/CoS2 grown on carbon fiber cloth for hybrid-supercapacitors with outstanding cyclic stability

Abstract

Improving the lifetime and energy density of energy storage devices has always been a major challenge. Here, CoS2 with a hollow structure derived from zeolite-imidazolate framework-67 was reconstructed on Co(OH)F nanowires. Co(OH)F nanowires contribute to ion/electron transmission and reduce transmission resistance, thereby promoting the stability of the electrode. CoS2 with a hollow porous structure contributes to the full infiltration of electrolytes, shortens the ion transmission distance, accelerates the redox reactions, and alleviates the volume expansion, thus improving the pseudocapacitance. Therefore, the prepared Co(OH)F/CoS2 displayed excellent specific capacity (233 mAh g−1). The assembled HSC Co(OH)F/CoS2//activated carbon in KOH solution could achieve a considerable energy density (63.9 Wh kg−1). Surprisingly, the specific capacitance accounts for 107.0% of the primary capacitance (20,000 cycles), demonstrating great cycling stability. This work presents a conceptual approach for the construction of abundant and promising electrodes for HSCs.