MoS₂/NiS Yolk–Shell Microsphere‐Based Electrodes for Overall Water Splitting and Asymmetric Supercapacitor

Abstract

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.

Defect‐Rich Heterogeneous MoS2/NiS2 Nanosheets Electrocatalysts for Efficient Overall Water Splitting

“…Then, we scratched the MoS 2 and NiS 2 powders from the carbon cloth, then mechanically mixed MoS 2 and NiS 2 with the atomic ratio of Mo:Ni = 1:1 (denoted as MoS 2 -NiS 2 ). [50,52,53] Consequently, these results further demonstrate the effect of the interface, which could enrich the active sites and promote the electronic transfer, and thus boost the sluggish water splitting efficiency. As shown in Figure S15 in the Supporting Information, it can be found that MoS 2 /NiS 2 shows much better HER and OER performances than that of mechanically mixed MoS 2 -NiS 2 sample.…”

Self‐Supportive Mesoporous Ni/Co/Fe Phosphosulfide Nanorods Derived from Novel Hydrothermal Electrodeposition as a Highly Efficient Electrocatalyst for Overall Water Splitting

“…The Tafel slope of NiCoFe‐PS nanorod/NF is better than those of IrO 2 based catalyst (97.8 mV dec −1 ), accounting for the fast kinetic process. In contrast, the performance of NiCoFe‐PS nanorod/NF is one of the best among reported catalysts for OER in Figure c …”

Hierarchical NiS@CoS with Controllable Core‐Shell Structure by Two‐Step Strategy for Supercapacitor Electrodes

“…Specifically, well‐regulated nanostructures not only improve the utilization of active materials, but also shorten the diffusion path of ions, thereby promoting the reaction kinetics of the electrodes and improving electrochemical performance . For example, Qin et al synthesized MoS 2 /NiS egg yolk‐shell microsphere structure, the specific capacitance at a current density of 0.2 A g −1 is 1493 F g −1 . Subramanian et al prepared NiS/CoS/PEDOT on a foamed nickel substrate by chemical bath deposition, showing a specific capacitance of 353 F g −1 at a current density of 15 mA cm −2 .…”