Lithium-sulfur batteries have attracted worldwide interest due to their high theoretical capacity of 1672 mAh g and low cost. However, the practical applications are hampered by capacity decay, mainly attributed to the polysulfide shuttle. Here, the authors have fabricated a solid core-shell γ-MnO -coated sulfur nanocomposite through the redox reaction between KMnO and MnSO . The multifunctional MnO shell facilitates electron and Li transport as well as efficiently prevents polysulfide dissolution via physical confinement and chemical interaction. Moreover, the γ-MnO crystallographic form also provides one-dimensional (1D) tunnels for the Li incorporation to alleviate insoluble Li S /Li S deposition at high discharge rate. More importantly, the MnO phase transformation to Mn O occurs during the redox reaction between polysulfides and γ-MnO is first thoroughly investigated. The S@γ-MnO composite exhibits a good capacity retention of 82% after 300 cycles (0.5 C) and a fade rate of 0.07% per cycle over 600 cycles (1 C). The degradation mechanism can probably be elucidated that the decomposition of the surface Mn O phase is the cause of polysulfide dissolution. The recent work thus sheds new light on the hitherto unknown surface interaction mechanism and the degradation mechanism of Li-S cells.

The fabrication of supramolecular chiral nanostructures from achiral materials without the need of pre-existing chirality is a major challenge associated with the origin of life. Herein, supramolecular chiral twisted nanoribbons of achiral oligoaniline derivatives were prepared via simply performing the chemical oxidation of aniline in an alcohol/water mixed solvent. In particular, the supramolecular chirality of the twisted nanoribbons could be controlled by facilely tuning the alcohol content in the mixed solvent. A tetra-aniline derivative CHON was attested to be the major component of the obtained nanoribbons. The main driving forces for the assembly of the oligoaniline derivative into twisted nanoribbons might be the π-π stacking and hydrogen bonding interactions among the chains which could be modulated by the alcohol content in the mixed solvent. The single-handed twisted nanoribbons could be used to separate chiral phenylalanine from a racemic mixture. Thus, it is highly anticipated that the supramolecular chirality endows π-conjugated molecules with potential application in chiral recognition.

Polyaniline multidimensional architectures from plate-like structures to flower-like superstructures have been successfully tailored by the oxidation polymerization in dilute aniline solution at room temperature, when the molar ratio of oxidant to monomer was altered in the range of 0.1:1-0.8:1. It was found that at low molar ratio (0.1:1-0.3:1) plate-like structures could be synthesized, while the as-synthesized product at the higher molar ratio (0.4:1-0.8:1) was flower-like superstructures; and the effect of monomer concentration on the shape of plate-like or flower-like architectures was also investigated. More importantly, their growth processes have been followed by measuring the morphological evolutions and chemical structures of products with the different reaction times, and then a plausible interpretation to their formation was brought forward through discussing the polymerization courses at two molar ratios (0.2:1 and 0.6:1). Besides, the molecular weight and conductivity of products obtained were also measured in this report.

A one-step route has been reported for the fabrication of poly(aniline-copyrrole) (PACP) copolymer hollow nanospheres via the oxidation polymerization of a mixture of aniline and pyrrole in the presence of Triton X-100. It was found that the variations in polymerization conditions, such as the concentrations of Triton X-100 and comonomers, and [pyrrole]/[aniline] molar ratios, could change the size and uniformity of copolymer hollow nanospheres. The result of DLS has attested the presence of the spherical Triton X-100 micelles swelled by the comonomers in reaction system, and such micelles might play template for the formation of hollow nanospheres, followed by developing a possible formation mechanism. The chemical structures and crystallinity of products were characterized by FTIR, UV-visible, 1 H NMR spectra, and XRD patterns, respectively, to prove the copolymer chemical structures of hollow nanospheres. The thermal-stability and solubility of PACP were improved compared with homopolymers (polyaniline and pyrrole). V V C 2008 Wiley Periodicals, Inc.

We reported the synthesis of nanostructure-covered rectangular submicrotubes of polyaniline in the doping state via the oxidation polymerization of aniline in the acidic solution of anionic surfactant. Both the concentrations of surfactant and inorganic acid employed in this preparing system are relatively low, which were essential to the successful fabrication of polyaniline hierarchical structures. We discussed the temperature dependence of polyaniline morphology and found that this synthesis admitted a wide range from 20 to 40 °C. After observing their growth processes, a tentative interpretation has been proposed to elucidate the formation of the tubular hierarchical structures in such a system. It was also found in this report that both SDS and HCl had profound impacts on the morphology of resulting product.