Microwave synthesis of NiSe2 nanoflakes for electrochemical conversion and energy storage

Metal chalcogenides have garnered considerable interest for electronic applications owing to their high electrical conductivity, along with unique structural, optical, and electrochemical properties. In this work, NiSe 2 nanoflakes were synthesized via a simple, low-cost microwave-assisted method, followed by calcination at two different temperatures (200 °C and 400 °C) for 2 h. Structural characterization through X-ray diffraction (XRD) and Raman spectroscopy confirmed the successful formation of cubic-phase NiSe 2 at 400 °C. Detailed morphological and elemental analyses revealed that calcination temperature plays a pivotal role in tuning the nanoflake morphology and surface characteristics. The multifunctional behavior of the NiSe 2 nanoflakes was evaluated for both supercapacitor and solar cell applications. Electrochemical measurements demonstrated a high specific capacitance of 598 F/g at 0.5 A/g, while photovoltaic tests achieved a power conversion efficiency (PCE) of 5.0 %. These results highlight the potential of NiSe 2 nanoflakes as efficient electrode materials for integrated energy storage and conversion devices.