Supercapacitor electrodes based on single crystal layered ZrX₂ (X = S, Se) using chemical vapor transport method

We synthesized single crystals of layered zirconium disulfide/diselenide (ZrX₂, X = S, Se) using the chemical vapor transport method. Our aim was to explore their potential as energy storage devices, specifically supercapacitors. To confirm the structures of our growth samples, we conducted various characterization tests. The semiconducting nature of ZrX₂, particularly in the 1T phase, limits its electrochemical performance. However, the 1T-ZrX₂ nanoflakes serve as highly stable conductive electrodes for high-performance supercapacitors. At a scan rate of 10 mV/s, ZrS₂ and ZrSe₂ exhibited specific capacitance values of 18.8 and 18 F/g, respectively. Notably, the metallic 1T-ZrSe₂ electrode outperformed 1T-ZrS₂ due to its greater conductive space observed from layer spacing, as confirmed by HRTEM analysis. The ZrSe₂ devices demonstrated exceptional stability, exceeding 90%. These findings highlight the promising potential of these 2D materials as supercapacitor electrodes, offering excellent specific capacitance values, conductivity and cycling stability.