Clarifying the Role of Ordered Mesoporous Carbon on a Separator for High-Performance Lithium–Sulfur Batteries

Despite the remarkably high theoretical energy density (∼2600 W h kg–1), lithium–sulfur (Li–S) batteries are still far from commercialization due to the poor intrinsic electrical conductivity of sulfur and the polysulfide shuttle effect. In order to resolve these problems, various sulfur host materials and modified separators have been investigated. Herein, we investigate a dual-functional interlayer by applying ordered mesoporous carbon (OMC) on a commercial separator as (1) OMC provides sufficient capability for adsorbing dissolved polysulfide and (2) the OMC interlayer acts as an additional current collector (reaction site). An innovative investigation of the behaviors of adsorbed sulfur species in the OMC interlayer during cycling is conducted by operando small-angle X-ray scattering and energy-dispersive X-ray spectroscopy analysis. The Li–S cell with a particular configuration, which has only Ketjenblack (KB) without sulfur on the cathode and the OMC interlayer containing 70 wt % of sulfur on the separator, proves that the OMC interlayer provides an additional reaction site. The comprehensive analyses suggest that the dual-functionalized OMC interlayer exhibits great potential for fabricating high-performance Li–S batteries. In addition, the OMC interlayer results in improved electrochemical performances for a high-sulfur-loading cathode (90 wt % S/KB)

Silver Nanowire–Conducting Polymer–ITO Hybrids for Flexible and Transparent Conductive Electrodes with Excellent Durability

Solution-processed silver nanowire (AgNW) films have attracted attention as transparent and conductive electrodes for flexible optoelectronic devices and touch screens, to replace sputtered indium–tin-oxide (ITO) films. However, the mechanical flexibility, environmental durability, and the optical (such as transparency and a haze) and electrical properties of the AgNW films should be improved for their practical application. In this work, high-performance and roll-to-roll processed AgNW-based hybrid electrodes comprising poly­(3,4-ethylenedioxythiophene):poly­(styrenesulfonate) (PEDOT:PSS) and/or ITO are introduced. The optical and electrical properties of the AgNW films combined with PEDOT:PSS, ITO, or both of them were systematically examined. Among the films, the AgNW–PEDOT:PSS–ITO hybrid film exhibits a high transmittance (88%) and a low sheet resistance (44 Ω sq^–1) with a small haze (1.9%). Moreover, the hybrid films show excellent durability to a variety of environmental stresses. By virtues of the high performance and durability, it is believed that the AgNW–PEDOT:PSS–ITO hybrid electrodes are highly suitable for practical use

Microporous Organic Network Hollow Spheres: Useful Templates for Nanoparticulate Co₃O₄ Hollow Oxidation Catalysts

Hollow microporous organic networks (<b>H-MON</b>s) were prepared by a template method using silica spheres. The shell thickness was delicately controlled by changing the synthetic conditions. The <b>H-MON</b>s were used as a template for the synthesis of nanoparticulate Co₃O₄ hollows which showed excellent catalytic performance in H₂O₂ oxidation

<i>In Operando</i> Monitoring of the Pore Dynamics in Ordered Mesoporous Electrode Materials by Small Angle X‑ray Scattering

To monitor dynamic volume changes of electrode materials during electrochemical lithium storage and removal process is of utmost importance for developing high performance lithium storage materials. We herein report an <i>in operando</i> probing of mesoscopic structural changes in ordered mesoporous electrode materials during cycling with synchrotron-based small angel X-ray scattering (SAXS) technique. <i>In operando</i> SAXS studies combined with electrochemical and other physical characterizations straightforwardly show how porous electrode materials underwent volume changes during the whole process of charge and discharge, with respect to their own reaction mechanism with lithium. This comprehensive information on the pore dynamics as well as volume changes of the electrode materials will not only be critical in further understanding of lithium ion storage reaction mechanism of materials, but also enable the innovative design of high performance nanostructured materials for next generation batteries

Metal–Organic Framework@Microporous Organic Network: Hydrophobic Adsorbents with a Crystalline Inner Porosity

This work reports the synthesis and application of metal–organic framework (MOF)@microporous organic network (MON) hybrid materials. Coating a MOF, UiO-66-NH₂, with MONs forms hybrid microporous materials with hydrophobic surfaces. The original UiO-66-NH₂ shows good wettability in water. In comparison, the MOF@MON hybrid materials float on water and show excellent performance for adsorption of a model organic compound, toluene, in water. Chemical etching of the MOF results in the formation of hollow MON materials

Visible-Light Driven Photocatalytic Degradation of Organic Dyes over Ordered Mesoporous Cd_<i>x</i>Zn_1–<i>x</i>S Materials

Highly ordered mesoporous Cd_<i>x</i>Zn_1–<i>x</i>S materials were obtained via a simple nanoreplication method using a mesoporous silica template with a 3-D bicontinuous cubic Ia3d mesostructure. Combined analyses using X-ray diffraction, N₂ sorption, electron microscopy, and diffuse reflectance UV–visible spectroscopy revealed that the ordered mesoporous ternary compound semiconductor materials exhibited well-developed crystalline frameworks, high surface areas of 80–120 m²g^–1, uniform mesopore sizes of about 20 nm, ordered arrangement of mesopores, and outstanding visible light absorption properties. Photocatalytic activities were investigated by degradation of methylene blue and rhodamine B under visible light over the mesoporous Cd_<i>x</i>Zn_1–<i>x</i>S materials. Due to the high surface area and outstanding light absorption properties, the ordered mesoporous Cd_<i>x</i>Zn_1–<i>x</i>S exhibited excellent photocatalytic performances for the degradation of methylene blue and rhodamine B. This study indicates a potential application of the mesoporous compound semiconductors in the efficient visible-light-driven photolysis of organics that may cause environmental pollution