Systematic design of hierarchical Ni3S2/MoO2 nanostructures grown on 3D conductive substrate for high-performance pseudocapacitors

Abstract

For high-performance pseudocapacitors, the rational design of nanoarchitectures has gained extensive attention to achieve superior pseudo-capacitive behaviors such as excellent energy storing ability and long-term cyclability. Here, we report systematically designed hierarchical Ni3S2/MoO2 (H-Ni3S2/MoO2) nanostructures directly grown on a 3D conductive substrate via a facile one-step synthesis route. The synthesized H-Ni3S2/MoO2 exhibits a high specific capacitance of 1376.1 F g(-1) at 1 mA cm(-2), a high energy density of 45.9 Wh kg(-1), and a good capacitance retention of 86.0% during 2000 cycles. These enhanced pseudo-capacitive features of H-Ni3S2/MoO2 are attributed to their unique nanoarchitectures favorable for pseudo-capacitive behavior as follows: (1) densely arrayed Ni3S2 nanoarchitectures consisting of the primary 1D nanowires and the secondary 2D nanosheets providing large electrolyte contact areas that can increase specific capacitances, and (2) well-engineered interfacial layer of MoO2 that can induce good electrochemical cyclability. Thus, our results suggest that the H-Ni3S2/MoO2 can be utilized as a promising pseudo-capacitive electrode for high-performance pseudocapacitors.