MnNbS/Polyaniline Composite-Based Electrode Material for High-Performance Energy Storage Hybrid Supercapacitor Device

Hybrid supercapacitor or supercapattery devices have gained significant attention for their impressive power (P-d) and energy densities (E-d), as well as their exceptional cyclic stability compared to traditional storage devices. In this study, manganese niobium sulfide (MnNbS) is synthesized using a hydrothermal method. To enhance the electrochemical performance of MnNbS, polyaniline (PANI) is blended at varying mass ratios. Initially, the electrochemical properties of MnNbS/PANI are evaluated using a three-electrode configuration, consisting of working, counter, and reference electrodes. At a current density of 2 A g(-1), MnNbS/PANI exhibits an improved specific capacity ((Cs)$\left(\right. C_{s} \left.\right)$) of 1366 C g(-1). Subsequently, to develop a supercapattery energy storage device, a two-electrode system is constructed. This setup offers enhanced performance and flexibility, making it an ideal choice for high-performance supercapacitors. Activated carbon (AC) and MnNbS/PANI are employed as the negative and positive electrodes, respectively, in the two-electrode system. Notably, the device demonstrates outstanding energy density (E-d) of 26.2 Wh kg(-1), power density (P-d) of 2072 W kg(-1), and specific capacity of 118 C g(-1). Furthermore, durability tests involving 1000 charge-discharge cycles reveal a capacity retention of 79%. This study suggests that MnNbS/PANI (at a weight ratio of 80/20%) holds promise as an electrode material for supercapattery applications.