MOF-Derived Hollow Co₃S₄ Quasi-polyhedron/MWCNT Nanocomposites as Electrodes for Advanced Lithium Ion Batteries and Supercapacitors

Transition metal sulfides/carbon nanocomposites are being extensively studied as electrode materials since a rationally designed structure incorporated with carbonaceous materials can eliminate pulverization caused by volume expansion during the cycling process and promote electron transport in the electrodes. Herein, we report a cobalt sulfide/multiwalled carbon nanotube (MWCNT) nanocomposite with a novel structure where MWCNTs penetrate through hollow Co 3 S 4 quasi-polyhedra and form conductive networks. The preparation of this unique structure involves sulfurization of ZIF-67/MWCNT precursors via solvothermal process and subsequent crystallization by thermal annealing. With the employment of TEM 3D reconstruction technology, a panoramic view of the as-prepared nanocomposites is demonstrated and the structure is thoroughly confirmed. Moreover, the hollow Co 3 S 4 /MWCNT nanocomposites exhibit high specific capacity and excellent cyclic stability as electrodes for both lithium ion batteries and supercapacitors. They delivered specific capacity of 1281.2 mAh g –1 after 50 cycles at 200 mA g –1 and 976.5 mAh g –1 after 500 cycles at 2 A g –1 . Also, they show a high capacitance of 638.5 F g –1 at current density of 30 A g –1 and capacitance retention of 78.98% after 5000 cycles.