Development of an efficient supercapacitor using hydrothermally synthesized nickel sulfide

Abstract

The current research explores the hydrothermal synthesis of nickel sulfide over a temperature range of 120–180°C, with advanced characterization used to assess features influencing its electrochemical behavior in supercapacitor applications. The temperature variation in the synthesis process results in a pure β-NiS phase at lower temperatures, while at higher temperatures, up to 180°C, mixed phases were confirmed by XRD, with FTIR revealing the characteristic vibrational modes of nickel sulfide. FE-SEM micrographs show a morphological transition from nanoflakes to microflowers to agglomerated flakes, influencing the specific surface area (10.45 m2g⁻1), for the sample synthesized at 140 °C, as determined by BET analysis. The electrochemical analysis of the fabricated electrodes was conducted in different electrolytes, revealing that NiS synthesized at 140°C achieves the highest capacitance of 294 Fg⁻1 at 1 A g⁻1 in KOH, establishing it as a promising candidate for supercapacitor applications.