Synthesis of HfSe ₂ and CuHfSe ₂ crystalline materials using the chemical vapor transport method and their applications in supercapacitor energy storage devices

This study reports the synthesis of highly crystalline layered HfSe 2 and CuHfSe 2 using the chemical vapor transport method and the investigation of their supercapacitor behavior. Various characterizations were performed in order to confirm and ascertain the structure of the synthesized materials. The CuHfSe 2 electrode exhibited better supercapacitor performance due to its higher conductivity, as confirmed by experimental analysis and density functional theory calculations. The semiconducting nature of HfSe 2 with a 2H phase mainly impedes its electrochemical performance. Further electrochemical analyses were conducted to test the stability of both electrode materials. Moreover, these new nanocrystals can be regarded as promising supercapacitor electrode materials with good specific capacitance, excellent cycling stability, and high energy density due to the unique microstructure of such 2D materials.