A facile one-step electrosynthesis of polypyrrole/nano-SbOx composite for supercapacitors

Abstract

The study depicts a one-step electrochemical synthesis of composite based on polypyrrole (PPy) and SbOx (Sb2O3, Sb2O5) on the graphite surface for the supercapacitor electrode in an acetonitrile solution including pyrrole monomer and Sb(BF4)3. PPy/SbOx composite on graphite plate is characterized using XPS, XRD, TEM, BET, and FESEM by comparing it with PPy homopolymer prepared in the same way. SbOx forms in nano-size and homogeneously encapsulates in PPy due to their simultaneous synthesis. The average pore size of the composite coating is 23.9 nm. The coated PG electrodes are tested in an H2SO4 electrolyte using CV, EIS, and GCD methods. SbOx nanoparticles enhance the capacitive performance of PPy due to the contribution of its catalytic and pseudocapacitive properties. The specific capacitance of the PPy/SbOx-coated PG electrode is 389.5 F g−1 at 5 A g−1 for 1.0 mg cm−2 loading. PPy/SbOx is synthesized in the presence of carboxymethyl cellulose (CMC) to provide stability to the coating. An asymmetric supercapacitor cell is fabricated by assembling the PPy/SbOx/CMC-coated and activated carbon-based graphite paper electrodes (10 mg cm−2 loading). While the potential window expands to 1.4 V, it delivers an energy density of 8.3 Wh kg−1, a power density of 3.5 kW kg−1, and a coulombic efficiency of 90% at 5 A g−1. Post-mortem analysis reveals that structural degradation of PPy in the composite limits long-term stability.