Rational designing of the composition and structure of electrode material is of great significance for achieving highly efficient energy storage and conversion in electrochemical energy devices. Herein, MoS2 /NiS yolk-shell microspheres are successfully synthesized via a facile ionic liquid-assisted one-step hydrothermal method. With the favorable interface effect and hollow structure, the electrodes assembled with MoS2 /NiS hybrid microspheres present remarkably enhanced electrochemical performance for both overall water splitting and asymmetric supercapacitors. In particular, to deliver a current density of 10 mA cm-2 , the MoS2 /NiS-based electrolysis cell for overall water splitting only needs an output voltage of 1.64 V in the alkaline medium, lower than that of Pt/C-IrO2 -based electrolysis cells (1.70 V). As an electrode for supercapacitors, the MoS2 /NiS hybrid microspheres exhibit a specific capacitance of 1493 F g-1 at current density of 0.2 A g-1 , and remain 1165 F g-1 even at a large current density of 2 A g-1 , implying outstanding charge storage capacity and excellent rate performance. The MoS2 /NiS- and active carbon-based asymmetric supercapacitor manifests a maximum energy density of 31 Wh kg-1 at a power density of 155.7 W kg-1 , and remarkable cycling stability with a capacitance retention of approximately 100% after 10 000 cycles.
Keywords: asymmetric supercapacitor; interface design; overall water splitting; yolk-shell structure.
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