Silanized palygorskite clay as a template for the preparation of polypyrrole-based nanocomposites for supercapacitor electrodes

Polypyrrole (PPy) is considered a promising electrode material for supercapacitors (SCs) due to its high specific capacitance; however, it exhibits low long-term cycling stability. To address this issue, the introduction of nanostructured materials into the PPy matrix yields nanocomposites that exhibit enhanced capacitance and improved cycling stability. In this study, PPy/palygorskite (PPy/Pal) nanocomposites were synthesized via in situ chemical polymerization of pyrrole on Pal templates. To enhance the compatibility between PPy and the clay, the surface of Pal was modified with a silane coupling agent (Pal-S). In a half-cell configuration, the PPy/Pal-S electrodes exhibit better electrochemical performance in terms of specific capacitance, rate capability, and cycling stability than the PPy electrode. The PPy/Pal-S nanocomposites achieved a maximum specific capacitance of 218 F g⁻¹ and retained 91% of their initial capacitance after 500 CV cycles. Moreover, the fabricated symmetric supercapacitor device elaborated with the PPy/Pal-S electrodes delivered a specific capacitance of 15 F g⁻¹ at 3 mA cm⁻², an energy density of 0.9 Wh kg⁻¹, a power density of 55 W kg⁻¹ with a cycling stability of 72% after 2000 GCD cycles, in a voltage range of 0.7 V. This study presents a novel strategy for constructing a 1D core/sheath PPy/Pal-S structure, which combines the advantageous properties of PPy (pseudocapacitance and electrical conductivity) and Pal-S clay (mechanical and chemical stability, 1D morphology, mesoporosity, and nanoscale size). Understanding the synergistic effects provides valuable insights for designing electrode materials with superior performance.