Construction of hierarchical honeycomb-like MnCo2S4 nanosheets as integrated cathodes for hybrid supercapacitors

Bimetallic transition metal sulfides (TMSs) are one class of promising electrode materials that have attracted wide attention for energy storage applications. Herein, we have presented a moderate and efficient synthetic methodology to rationally design and construct hierarchical honeycomb-like manganese cobalt sulfide nanosheets (MnCo2S4 NSs) as integrated cathodes for hybrid supercapacitors (HSCs). The anion-exchange process performed in the sulfidation reaction has significantly improved the electrochemical performance of the MnCo2S4 NSs, resulting in a superior areal capacity of 0.837 mA h cm−2 at 3 mA cm−2, a superb rate capability, and an admirable cycling lifespan with 92.3% of the initial capacity retained after 10,000 cycles. Moreover, MnCo2S4 NSs are directly used as integrated cathode and iron oxide particles encapsulated in reduced graphene oxide (Fe2O3@rGO) is employed as the anode to assemble the HSC. The as-assembled MnCo2S4 NSs//Fe2O3@rGO HSC delivers a superb energy density of 61.4 Wh kg−1 with an admirable cycling lifespan of 90.4% of capacity retention after 10,000 cycles. Besides, two HSC modules connected in series can power a homemade light-emitting diode (LED) device for 23 min, highlighting its potential practical prospects in energy storage systems.