α-MnS@Co3S4 hollow nanospheres assembled from nanosheets for hybrid supercapacitors

Abstract

• Nanosheet assembled hollow α-MnS@Co 3 S 4 spheres (NSH-MCS) were fabricated by an effective strategy. • The NSH-MCS sample was chosen as an efficient positive electrode for hybrid supercapacitors. • A hybrid supercapacitor is constructed using NSH-MCS and activated carbon with desirable energy density. Nanostructured mixed metal sulfides (MMSs) have emerged as a prominent kind of material for use in the fields of energy storage thanks to their intrinsic safety and good theoretical specific capacity. In this paper, nanosheet assembled hollow α-MnS@Co 3 S 4 spheres (NSH-MCS) with special morphology are synthesized and evaluated as an effective positive electrode for the hybrid supercapacitors. The synthesis process starts with the growth of the Co-based zeolitic imidazolate framework (ZIF-67) nanosheets onto manganese-glycerate (Mn-G) solid spheres. The direct sulfidation of the Mn-G@ZIF-67 nanostructures leads to the formation of NSH-MCS. The special structure can provide rich mass/electron transfer channels, meanwhile prevent the accumulation of nanosheets. Taking advantage of these great merits, the NSH-MCS based electrode discloses appealing electrochemical features including an impressive capacity value of 283.3 mAh/g (1019.9C/g) at 1 A/g with desired rate performance of 81.5% at 25 A/g and significant longevity of 92.7% over 10,000 cycles at 15 A/g. Also, a hybrid supercapacitor assembled with NSH-MCS positive electrode and AC (activated carbon) negative electrode proves desirable performance, such as a good energy density (54.9 Wh/kg at 753 W/kg) and excellent longevity of 90.5% after 10,000 cycles at 15 A/g. The straightforward strategy introduced in this paper can open an effective avenue for the fabrication of various MMSs for other applications.