Facile synthesis of flower-like cobalt sulfide hierarchitectures with superior electrode performance for supercapacitors

We demonstrate a simple and environmental friendly strategy to synthesize Co_1−xS flower-like architecture constructed by nanosheets through a solution-based route using L-cysteine as chelating agent and sulfur source. The crystal structure and morphology of the as-prepared products reveal that the diethanolamine solvent is the key factor to form of flower-like Co_1−xS hierarchitectures. A possible synthesis mechanism for this hierarchical flower-like Co_1−xS nanostructure was proposed by varying Co/S ratio. When applied as electrode materials for supercapacitors, the specific capacitance is 674 F g⁻¹ and 603 F g⁻¹ at 3 A g⁻¹ and 13 A g⁻¹ respectively. After 1000 cycles at high current density of 5 A g⁻¹, specific capacitance of 548 F g⁻¹ still remained. The electrochemical measurements demonstrate high-rate capacity and good cycle stability of the flower-like Co_1−xS nanostructures, suggesting a great potential to be used as supercapacitor electrode.