Plasma-Assisted Synthesis of NiSe Ultrathin Porous Nanosheets with Selenium Vacancies for Supercapacitor.

Two-dimensional (2D) NiSe nanosheets with porous ultrathin structure and selenium vacancies (NiSe PNS) are synthesized via plasma-assisted dry exfoliation for supercapacitor. The specific capacitance of the NiSe PNS is 466 F g in 1 M KOH electrolyte, which is much higher than those of NiSe ultrathin nanosheeets (328 F g) and NiSe particles (251 F g). After 1000 cycles, the specific capacitance of the NiSe PNS can be well-maintained, indicating its high cycling stability. The superior performance arose from its high conductivity, short electrolyte diffusion distance, and large specific surface area.