Su-Ryeon Yun

Synthesis and control of the shell thickness of polyaniline and polypyrrole half hollow spheres using the polystyrene cores

Polyaniline (Pani) and polypyrrole (Ppy) half hollow spheres with different shell thicknesses were successfully synthesized by three steps process using polystyrene (PS) as the core. The PS core was synthesized by emulsion polymerization. Aniline and pyrrole monomers were polymerized on the surface of the PS core. The shells of Pani and Ppy were fabricated by adding different amounts of aniline and pyrrole monomers. PS cores were dissolved and removed from the core shell structure by solvent extraction. The thicknesses of the Pani and Ppy half hollow spheres were observed by FE-SEM and FE-TEM. The chemical structures of the Pani and Ppy half hollow spheres were characterized by FT-IR spectroscopy and UV-Vis spectroscopy. The shell thicknesses of the Pani half hollow spheres were 30.2, 38.0, 42.2, 48.2, and 52.4 nm, while the shell thicknesses of the Ppy half hollow spheres were 16.0, 22.0, 27.0, and 34.0 nm. The shell thicknesses of Pani and Ppy half hollow spheres linearly increased as the amount of themonomer increased. Therefore, the shell thickness of the Pani and Ppy half hollow spheres can be controlled in these ranges.

The synthesis and electrochemical performance of aniline based conducting polymers as cathode materials for lithium ion batteries

The PDTDA and P(2-ATP), which have polyaniline main chain and bonds structure, were easily polymerization by chemical oxidation method. Although doped polyaniline was not soluble, doped PDTDA and P(2-ATP) were soluble. The chemical structure of dedoped and doped PDTDA and P(2-ATP) was characterized by FT-IR and XPS analysis. We studied the electrochemical performance such as the charge-discharge ability, discharge capacity, and cyclic voltammogram of them. The discharge capacities of PDTDA and P(2-ATP) after 50th cycle were ~38 and ~37mAh/g. The discharge capacities of PDTDA and P(2-ATP) as a function different current after initial stabilized step were measured. Recovering rates after high C-rate at 0.1C are ~92 % (PDADT) and ~50 %(P(2-ATP).