Recent advances in polyaniline research: Polymerization mechanisms, structural aspects, properties and applications

Performance improvement of polysulfone ultrafiltration membrane using PANiEB as both pore forming agent and hydrophilic modifier

The PANI/Mesoporous MnO2 composites were prepared through a simple one step method and we introduced the KI-H2SO4 solution as the electrolyte of PANI/MnO2 composites creatively. The characterization of structure, morphology, and composition are obtained by X-ray diffraction, Fourier transform infrared spectroscopy, thermal gravity analysis, Raman spectra, and scanning electron microscope. The electrochemical performances were investigated by constant-current charge–discharge, the voltammetry curve, and alternating current (AC) impedance technique. The specific capacitance of composites is 1405 F/g, which is almost 10 times larger than MnO2 (158 F/g). We also find that the iodide concentration is closely related to the specific capacitance. Therefore, we explored the specific capacitance at different iodide concentration (0.05, 0.1, 0.2, 0.5, and 1 M), the results indicated that the specific capacitance reached a maximum value (1580 F/g) at 0.5 mol/L. Additionally, the PANI/Mesoporous MnO2 composites not only exhibited a good ratio discharge property (857 F/g) at high current density, but also revealed an excellent cycling stability after 500 cycles, which retained 90% of the original specific capacitance.

High Specific Capacitance of Polyaniline/Mesoporous Manganese Dioxide Composite Using KI-H2SO4 Electrolyte

A high conductivity and surface area are the most highly desired properties of an electrocatalyst. Herein, we report a novel technique to synthesize highly conductive and microporous N and S-doped carbon from polyaniline (PANI) via a simple, template-free hydrothermal method followed by carbonization in the presence of iodine. The iodine treatment removes a large amount of the attached oxygen atoms and other heteroatoms and, as a consequence, increases the carbon content. Thus, the iodine treatment decreases the doping of catalytically active heteroatoms, which is unfavourable for the ORR, but at the same time, significantly increases the electrical conductivity, which is beneficial for the ORR. In particular, iodine-treated carbonized PANI (CPANI) shows an exceptionally high conductivity i.e., about 3 times that of untreated CPANI. Iodine treatment is also found to enhance the micropore surface area of the PANI during carbonization without using a harmful activating agent or a hard template. An electrocatalytic study indicates that the activity of the iodine-treated sample is considerably higher than that of an untreated sample. This remarkable upsurge in activity is mainly attributed to the large increase in the conductivity and surface area of the iodine-treated sample. The ORR activity is discussed in terms of the heteroatom content, surface area and conductivity of the carbon. This convenient, innovative approach can offer new possibilities for the design of future highly efficient fuel cell electrocatalysts.

S. Adhikari

Papers

Enhanced conductivity in iodine doped polyaniline thin film formed by thermal evaporation