Preparation And Electrochemical Properties Of Novel Conducting Polymer Composites

Supercapacitor is a new type of energy storage device and its performance is mostly dependent on the electrode materials. In order to develop high-performance electrode materials for supercapacitors, several methods were introduced to prepare polypyrrole/manganese oxide/graphite felt composites (PPy/MnO2/GF), polyaniline/manganese oxide/graphite felt composites (PANI/MnO2/GF) and nickel cobalt oxide/polyaniline/graphite felt composite (NiCo2O4/PANI/GF) in this work. Furthermore, the structure, morphology and electrochemical properties of these composites were characterized.1. PPy/MnO2/GF composite was prepared via one-step electrochemical method, and the effect of Mn2+ concentration on the electrochemical properties of the prepared composite was investigated. The results showed that the composite (PYMG50) prepared in the electrolyte containing 50 mmol L-1 Mn2+ exhibited the highest specific capacitance. And its specific capacitance was much larger than that of MnO2/GF and PPy/GF, which may be attributed to the synergistic effect of MnO2 and PPy.2. PPy/MnO2/GF composite was prepared by pulse electrodeposition, and the effects of pulse parameters on the morphology and the electrochemical properties of the composite were studied. The results showed that the composite (PYMG-p-3) prepared by reverse pulse electrodeposition had porous structure, and its morphology was different from that of the other two samples. Moreover, the specific capacitance of PYMG-p-3 was the largest. This may be ascribed to the porous structure of PYMG-p-3 which can facilitate easy access of electrolyte to the active material and enhance the electrochemical properties of the composite.3. PPy/MnO3/GF composite was prepared through chemical redox reaction, and the effects of react temperature on the morphology and the electrochemical properties of the composite were investigated. With the increase of react temperature, the morphology of PPy/MnO2 changed from nano-flower shape to network structure. Moreover, the composite (PYMG-HT) prepared at 50 ℃ displayed the highest specific capacitance, which may be owing to the unique network structure facilitating easy access of electrolyte to the active material and enhancing the electrochemical performance of the composite.4. PANI/MnO2/GF composites were prepared via two-step and one-step electrochemical methods, respectively. In the composite (PAMG-t) prepared by two-step electrochemical method, MnO2 nanoparticles were deposited on PANI and partially into PANI layer. At the current density of 0.5 A g-1, the specific capacitance of PAMG-t reached 629.4 F g-1. While in the composite (PAMG-o) prepared by one-step electrochemical method, PANI/MnO2 flakes were deposited on GF fiber. And the specific capacitance of PAMG-o at the current density of 0.5 A g"1 was 575.3 F g"15. PANI/MnCO2/GF composite was prepared by pulse electrodeposition, and the effects of pulse parameter on the morphology and the electrochemical properties of the composite were studied. The results showed that the composite (PAMG-p-3) prepared by reverse pulse electrodeposition had dense PANI/MnO2 nanoparticles on the surface of GF and its morphology was different from that of the other two samples. The specific capacitance of PAMG-p-3 was the largest. This may be resulted from the nanoparticle structure of PANI/MnO2 which can facilitate easy access of electrolyte to the active material and enhance the electrochemical performance of the composite.6. PANI/MnCO2/GF composite was prepared through interfacial chemical technique, and the effects of react temperature on the morphology and the electrochemical properties of the composite were investigated. With the increase of react temperature, the PANI/MnO2 changed from blocks to porous submicron spheres. Moreover, the composite (PAMG-HT) prepared at 50 ℃ displayed the highest specific capacitance, which may be due to the porous structure and high dispersion of PANI/MnO2 facilitating easy access of electrolyte to the reactive material and enhancing the electrochemical properties of the composite.7. NiCo2O4/PANI/GF and NiCo2O4/GF composites were prepared via electrochemical deposition combined with thermal treatment. The NiCo2O4/PANI in NiCo2O4/PANI/GF composite was flake-like, with nanoparticles inside. The NiCo2O4 nanoparticles in NiCo2O4/GF agglomerated at some positions. NiCO2O4/PANI/GF exhibited higher electrochemical performance, which may be ascribed to the participant of PANI providing additional electron transport channel and enhancing the electrochemical performance.