Fine tuning of supercapacitor performance through compositional and morphological engineering of siloxene-polyaniline composites

Recent research has paid attention to the establishment of new two-dimensional (2D) hetero-structures for supercapacitor electrodes with silicon-based 2D materials due to their compatibility with established silicon semiconductor technologies. In this study, we developed the siloxene-polyaniline hetero-structure to explore its electrochemical performance for supercapacitor applications. We synthesized the composites by systematically varying the amount of polyaniline (PANI) and tuning its morphology from granular to nanofiber form to optimize the overall electrochemical performance. Siloxene, a silicon-based 2D material, not only provides the structural stability to PANI, but also acting as a supportive template to prevent PANI degradation. On the other hand, PANI enhances the conductivity and pseudocapacitive properties, and also reducing siloxene sheet restacking. To evaluate these effects, we conducted electrochemical tests on the composites using both three-electrode and symmetric device configurations to capture specific capacitance, rate capability, and cycling stability. Notably, the siloxene-PANI nanofiber composite (SPA-NF) achieved a specific capacitance of 785 F g⁻¹ at a current density of 1 A g⁻¹ in a 1 M H₂SO₄ electrolyte with excellent rate capability, that surpassing other compositions. The symmetric supercapacitor device assembled with SPA-NF demonstrated a specific capacitance of 465 F g⁻¹, an energy density of 93 Wh kg⁻¹, and a power density of 1199 W kg⁻¹, with 94.6 % stability over 10,000 cycles, indicating strong potential for practical applications in the field of high-performance energy storage device.