Controlled synthesis of MOF-derived quadruple-shelled CoS2 hollow dodecahedrons as enhanced electrodes for supercapacitors

Abstract

Hollow nanostructures with high complexity in shell architectures have attracted tremendous interest in electrode materials for energy storage and conversion because of their unique structural features. However, the synthesis of delicate structures for hollow metal sulfides are still difficult. Herein, we demonstrate the designed synthesis of porous quadruple-shelled CoS2 hollow dodecahedrons with the concave surfaces through a template engaged formation process. Uniform yolk-shell Co3O4 dodecahedrons are first synthesized from zeolitic imidazolate framework-67 and then transformed into quadruple-shelled CoS2 hollow dodecahedrons through the reaction with sulfur powder. As the result of the assembly of the advantages from materials and structures, when evaluating as electrodes for supercapacitors, the porous quadruple-shelled CoS2 shows a high specific capacity of 375.2 C g−1 with a good rate performance and excellent stability with 92.1% retention after 10000 cycles. Moreover, the assembling quadruple-shelled CoS2//active carbon asymmetric supercapacitor achieves a high energy density of 52.1 Wh kg−1, excellent specific capacitance (146 F g−1 at 0.5 A g−1), and electrochemical cycling stability (89% retention after 5000 cycles). The improved electrochemical performance of quadruple-shelled CoS2 hollow dodecahedrons demonstrates the importance of design of hollow electrodes materials with higher complexity.