Dual-ZIF-derived "reassembling strategy" to hollow MnCoS nanospheres for aqueous asymmetric supercapacitors.

ABSTRACT

Construction of delicate nanostructures with a facile, mild-condition and economical method is a key issue for building high-performance electrode materials. We demonstrate a facile and novel "reassembling strategy" to hollow MnCoS nanospheres derived from dual-ZIF for supercapacitors. The spherical shell's surface structure, thickness and Mn distribution were controlled by regulating the solvothermal reaction time. The chemical composition, phases, specific surface areas and microstructure were studied and the electrochemical performances were systematically estimated. As the unique low-crystalline and optimized hollow nanosphere structure contributes to increasing active sites, MnCoS nanospheres exhibit excellent electrochemical performance. The test results show that the specific capacitance increases with increasing solvothermal time, and the MCS with a 5 h reaction time exhibits optimal electrochemical properties with a high specific capacity of 957 C g-1 (1 A g-1). Furthermore, an MCS-5//AC asymmetric supercapacitor device delivers a specific energy as high as 36.9 W h kg-1 at a specific power of 750 W kg-1.