Yiheng Wang

Rational construction of core–shell Ni3S2@Ni(OH)2 nanostructures as battery-like electrodes for supercapacitors

Rationally constructing hybrid nanostructure electrodes is a promising approach for the development of high-performance supercapacitors. Here, we propose the fabrication of Ni3S2@Ni(OH)2 nanostructures directly on Ni foam by employing hydrothermal and chemical bath processes. In this core–shell nanostructure, the design of conductive Ni3S2 nanorods directly on Ni foam without organic binders could ensure intimate contact and fast electron transport. Meanwhile, porous Ni(OH)2 nanosheets coated on conductive Ni3S2 nanorods can effectively supply large surface areas with electrolyte and provide fast ion diffusion. Consequently, the as-fabricated Ni3S2@Ni(OH)2 nanostructures showed good electrochemical performance, such as high capacitance up to 3.55 F cm−2 and a good capacity retained after 10 000 cycles of about 85%. Furthermore, an asymmetric device, based on Ni3S2@Ni(OH)2 and activated carbon, was also fabricated and achieved a maximum energy density of 60.5 W h kg−1 at 1159 W kg−1. These results suggest that the as-designed core–shell Ni3S2@Ni(OH)2 nanostructures demonstrated in this research are promising electrode materials for energy storage.

Designing and constructing core-shell NiCo2S4@Ni3S2 on Ni foam by facile one-step strategy as advanced battery-type electrodes for supercapattery

Herein, we successfully design and construct core-shell nanostructured NiCo2S4@Ni3S2 directly on Ni foam by a scalable and effective one-step strategy. Further, through simply and accurately controlling the concentration of sulfur source, various nanostructures of NiCo2S4@Ni3S2 arrays in situ on Ni foam are successfully synthesized. The intriguing core-shell structures and integrated electrode configurations endow NiCo2S4@Ni3S2 electrode a large electroactive sites, fast electron transport path and sufficient contacts with electrolyte. Serving as free-standing electrode, as-fabricated NiCo2S4@Ni3S2 arrays exhibit the high specific capacity (4.55 C cm-2 at 5 mA cm-2), good rate performance and good cycling stability. Impressively, current research provides a general, scalable and effective one-step strategy for constructing core-shell nanostructures for energy storage devices.