Nickel metal-organic framework microspheres loaded with nickel-cobalt sulfides for supercapacitor electrode materials

Metal-organic frameworks (MOFs) are commonly used for template and precursor for supercapacitor electrodes. MOFs are interesting due to excellent specific surface areas and pore structures. Two-dimensional nanosheets suffer from the disadvantages of random growth and easy agglomeration, which significantly limit their applications. In this study, Ni-Co sulfides with unique morphology were designed using a simple in situ sulfidation method, with Ni-MOF used as the substrate material. The unique three-dimensional structures can offer many reaction sites to guarantee electron transfer. The samples obtained (Ni7S6@NiCo2S4) exhibited good electrochemical performance. The composite electrode material had a capacity value of 1636 F g (1) in a 3 M KOH. In addition, devices comprising with activated carbon had a specific energy of 53 Wh kg (1) and a specific power of 810 W kg (1). The asymmetric supercapacitor (ASC) exhibited outstanding cycling of 87 % after 5000 cycles. This study demonstrates a flexible method for activating MOFs to enhance the capabilities of supercapacitor materials. Thus, this method maintains a well-defined stacking structure of nanosheets while enriching the active sites, it is promising for the applications of MOF derivatives.

Automated summary

This study designs unique morphology Ni-Co sulfides using a simple in situ sulfidation method with Ni-MOF as the substrate material. The obtained samples exhibit good electrochemical performance and outstanding cycling in an asymmetric supercapacitor. This flexible method enhances the capabilities of supercapacitor materials.