Hydrothermally Synthesized SrS/Polyaniline Nanocomposite Electrodes for Asymmetric Supercapacitor Devices with Enhanced Charge-Storage Performance

The growing demand for efficient and sustainable energy-storage systems has intensified efforts to develop materials capable of delivering both high power output and reliable capacity retention. Conventional supercapacitors excel in rapid charge–discharge processes and offer outstanding cycling durability; however, their inherently low energy density limits large-scale use. In contrast, batteries provide high energy densities but typically display slower power response and poorer rate capability. Consequently, hybrid storage systems that merge capacitive and faradaic mechanisms have emerged as a compelling strategy to overcome these shortcomings. In this study, a SrS/polyaniline (SrS/PANI) nanocomposite was fabricated via hydrothermal synthesis and evaluated as an electrode material for hybrid supercapacitor architectures. Structural and morphological characterisation confirmed the formation of a nanoscale composite with well-integrated phases. Electrochemical performance was first evaluated in a three-electrode half-cell configuration, where the optimized SrS/PANI (50/50 wt%) electrode delivered a GCD-derived specific capacity of 580 C g−1 at 0.4 A g−1. The electrode was then assembled into an asymmetric two-electrode device, which achieved an energy density of 18 Wh kg−1, a power density of 2980 W kg−1, and 75% capacity retention after 1000 cycles. Overall, the findings indicate that the SrS/PANI composite exhibits improved charge-storage behaviour arising from the combined contribution of redox-active SrS and the conducting-polymer component PANI, underscoring its promise for hybrid energy-storage applications.