Electrode designs, which can accommodate severe volume changes (ca. 400 %) of silicon anode materials upon lithium insertion, are the main prerequisite for high-performance lithium ion batteries. Among various techniques investigated for this purpose, a robust polymeric binder is a promising means to inhibit mechanical fracture of silicon negative electrodes during cycling.Lithium ion batteries (LIBs) are one of the most promising energy storage devices owing to their high power and energy densities. [1] For LIBs, silicon is a promising candidate anode material owing to its high theoretical specific capacity of 4200 mAh g À1 for Li 4.4 Si, low electrochemical potential between 0 and 0.4 V versus Li/Li + , and small initial irreversible capacity compared with other metal-or alloy-based anode materials. [2] Nevertheless, the practical application of silicon to LIBs is still quite challenging because silicon suffers from severe volume changes (ca. 400 %) during Li + insertion and extraction processes, which breaks electrical contact between the silicon particles and results in degradation of electrodes and rapid capacity loss. [3] To alleviate volume change, silicon nanoparticles and porous silicon materials have been extensively studied because the smaller particles undergo smaller absolute volume change. [4] The aggregation of silicon particles upon cycling, however, accelerates the degradation of electrodes. Thus, many efforts have focused on the synthesis of silicon-carbon composites to prevent the agglomeration of silicon, resulting in a highly improved cycle performance. [5] Although remarkable improvements in the electrochemical performance of silicon-based anodes have been achieved, electrode deformation and external cell expansion still occur because of the inherent volume change of silicon. This large cell volume change is the main factor limiting the commercialization of silicon-based anode materials.

We present a promising electrolyte candidate, Mg(TFSI)2 dissolved in glyme/diglyme, for future design of advanced magnesium (Mg) batteries. This electrolyte shows high anodic stability on an aluminum current collector and allows Mg stripping at the Mg electrode and Mg deposition on the stainless steel or the copper electrode. It is clearly shown that nondendritic and agglomerated Mg secondary particles composed of ca. 50 nm primary particles alleviating safety concern are formed in glyme/diglyme with 0.3 M Mg(TFSI)2 at a high rate of 1C. Moreover, a Mg(TFSI)2-based electrolyte presents the compatibility toward a Chevrel phase Mo6S8, a radical polymer charged up to a high voltage of 3.4 V versus Mg/Mg(2+) and a carbon-sulfur composite as cathodes.

Conjugated polymers with a one-dimensional p-orbital overlap exhibit optoelectronic anisotropy. Their unique anisotropic properties can be fully realized in device applications only when the conjugated chains are aligned. Here, we report a molecular design principle of conjugated polymers to achieve concentration-regulated chain planarization, self-assembly, liquid-crystal-like good mobility and non-interdigitated side chains. As a consequence of these intra- and intermolecular attributes, chain alignment along an applied flow field occurs. This liquid-crystalline conjugated polymer was realized by incorporating intramolecular sulphur-fluorine interactions and bulky side chains linked to a tetrahedral carbon having a large form factor. By optimizing the polymer concentration and the flow field, we could achieve a high dichroic ratio of 16.67 in emission from conducting conjugated polymer films. Two-dimensional grazing-incidence X-ray diffraction was performed to analyse a well-defined conjugated polymer alignment. Thin-film transistors built on highly aligned conjugated polymer films showed more than three orders of magnitude faster carrier mobility along the conjugated polymer alignment direction than the perpendicular direction.

Among the phenomena related to the surface rearrangement of cations in perovskite-based oxides, A-site cation enrichment, Sr in particular, near the surface has been frequently observed. Upon annealing in an oxidizing atmosphere, Sr is often enriched on the surface as compared with the bulk composition of the material, which eventually forms Sr-rich phases or rearranges the crystal structure of the surface. This Sr segregation changes the structure and composition of the perovskite surfaces and thus affects the stability of the materials and the reactivity with gas phases. In this regard, many studies have been carried out in the field of solid oxide electrochemical cells (SOCs). In this review, we summarize the latest research efforts on Sr segregation in perovskite-based SOC O 2 electrodes, with a focus on how excess Sr is present. We then discuss the origins of Sr segregation and suggest strategies for suppressing it to realize high-performance perovskite-based O 2 electrodes.

Polymeric dielectrics having different ratios of hydroxyl groups were intentionally synthesized to investigate the effect of hydroxyl groups on the electrical properties of pentacene-based organic thin film transistors (OTFTs). Large hysteresis usually observed in OTFT devices was confirmed to be strongly related to the hydroxyl bonds existing inside of polymeric dielectrics and could be reduced by substituting with cinnamoyl groups. Although the hydroxyl groups deteriorate the capacitance-voltage characteristics and gate leakage current densities, exceptionally high hole mobility (5.5cm2V−1s−1) could be obtained by increasing the number of hydroxyl groups, which was not caused by the improvement of pentacene crystallinity but related to the interface characteristics.