Integration of polypyrrole with metal complexes of 2,6-pyridinedicarboxylic acid and their electrochemical studies as potential electrode material in supercapacitor application / Sadia Tanzim

Sadia , Tanzim (2023) Integration of polypyrrole with metal complexes of 2,6-pyridinedicarboxylic acid and their electrochemical studies as potential electrode material in supercapacitor application / Sadia Tanzim. Masters thesis, Universiti Malaya.

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Abstract

In this study, four transition metal complexes of PDC namely: AgPDC, CdPDC, CuPDC and ZnPDC were synthesized, characterized and integrated with polypyrrole (PPY) to create four new composite materials: PPY-AgPDC, PPY-CdPDC, PPY-CuPDC and PPY-ZnPDC for studying their electrochemical performance. PPY and the composites were synthesized using two techniques: in-situ oxidative polymerization (powder) and electrochemical polymerization (thin films). The composite materials were characterized by FTIR spectroscopic technique, powder X-ray diffraction technique, TGA, FESEM and EDX. XRD studies reveal AgPDC, CuPDC and ZnPDC were similar to previously reported structures whereas CdPDC was identified as a new crystal structure. FESEM analysis of powder composites revealed that the complexes were encapsulated by the microspheres of PPY with an average size of 0.5 μm whereas, analysis of the film composites revealed that the complexes were embedded irregularly within the PPY microspheres with an average size of 1.2 μm. Powder PPY and its composites were mixed with carbon black and PVDF to form slurry and coated evenly over graphite sheet as working electrode. With Ag/AgCl reference and Pt wire counter electrode, the CV was performed in room temperature at potential range of -0.2 V to +0.8 V in 1 M H2SO4 electrolyte. Thin films of PPY and its composites on ITO glass as working electrode with Ag/AgCl reference and graphite rod counter electrode was used to perform CV in room temperature at potential range of -0.5 V to +0.9 V in 0.01 M K3[Fe(CN)6] + 0.1M KCl electrolyte solution. Based on the shape of the voltammograms at 10 mV.s-1 scan rate, the powder composites exhibited improved capacitive behaviour and the film composites exhibited better pseudocapacitive behaviour than PPY. EIS of the powder composites was performed in the same electrochemical cell set-up as CV, meanwhile the films were extracted from ITO and performed directly. The conductivity values determined for PPY powder slurry was 8.62 × 10-4 S.cm-1 and for PPY film was 1.04 × 10-5 S.cm-1. Powder composites exhibited conductivity in the range of 1.03 × 10-3 – 4.41 × 10-3 S.cm-1 and film composites were in range of 4.78 × 10-5 – 2.16 × 10-5 S.cm-1. All fabricated composites achieved higher conductivities, reduced resistance, than pure PPY. These electrochemical traits are promising for their future application as supercapacitors.

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