It is highly desirable to develop advanced electrode structures of lithium–sulfur (Li–S), which enable high energy density, long life, low cost, and environmental benignity. In particular, suppression of polysulfide (PS)-shuttle behavior that occurs during electrochemical reaction in Li–S batteries is the most important challenge for practical, large-scale applications. In this work, a natural-wood-derived polymer, lignosulfonate sodium salt (LSS), is employed as a binder material for Li–S, showing superior capacity and cycle retention because of its unique chemical structure. LSS with amphiphilic functional groups can easily disperse hydrophobic electrode components in water and effectively block PS dissolution by its electrostatic repulsion force. Moreover, with enhanced Li ionic conductivity, the rate capability of the S cathode is maintained at ∼661 mA h g–1 at a current rate of 1675 mA g–1 and stable areal capacity of ∼1.55 mA h cm–2 is obtained with pristine S active material.

Directed self-assembly (DSA) of block copolymers (BCPs) with a high Flory−Huggins interaction parameter (χ) provides advantages of pattern size reduction below 10 nm and improved pattern quality. Despite theoretical predictions, however, the questions of whether BCPs with a much higher χ than conventional high-χ BCPs can further improve the line edge roughness (LER) and how to overcome their extremely slow self-assembly kinetics remain unanswered. Here, we report the synthesis and assembly of poly-(4vinylpyridine-b-dimethylsiloxane) BCP with an extremely high χ-parameter (estimated to be approximately 7 times higher compared to that of poly(styrene-b-dimethylsiloxane) − a conventional high-χ BCP) and achieve a markedly low 3σ line edge roughness of 0.98 nm, corresponding to 6% of its line width. Moreover, we demonstrate the successful application of an ethanolbased 60 °C warm solvent annealing treatment to address the extremely slow assembly kinetics of the extremely high-χ BCP, considerably reducing the self-assembly time from several hours to a few minutes. This study suggests that the use of BCPs with an even larger χ could be beneficial for further improvement of self-assembled BCP pattern quality.

The interfacial effect between a metal catalyst and its various supporting transition metal oxides on the catalytic activity of heterogeneous catalysis has been extensively explored; engineering interfacial sites of metal supported on metal oxide has been found to influence catalytic performance. Here, we investigate the interfacial effect of Pt nanowires (NWs) vertically and alternatingly stacked with titanium dioxide (TiO 2 ) or cobalt monoxide (CoO) NWs, which exhibit a strong metal−support interaction under carbon monoxide (CO) oxidation. High-resolution nanotransfer printing based on nanoscale pattern replication and e-beam evaporation were utilized to obtain the Pt NWs cross-stacked on the CoO or TiO 2 NW on the silicon dioxide (SiO 2 ) substrate with varying numbers of nanowires. The morphology and interfacial area were precisely determined by means of atomic force microscopy and scanning electron microscopy. The cross-stacked Pt/ TiO 2 NW and Pt/CoO NW catalysts were estimated with CO oxidation under 40 Torr CO and 100 Torr O 2 from 200 to 240 °C. Higher catalytic activity was found on the Pt/CoO NW catalyst than on Pt/TiO 2 NWs and Pt NWs, which indicates the significance of nanoscale metal−oxide interfaces. As the number of nanowire layers increased, the catalytic activity became saturated. Our study demonstrates the interfacial role of nanoscale metal−oxide interfaces under CO oxidation, which has intriguing applications in the smart design of catalytic materials.

Despite the outstanding physical and chemical properties of two-dimensional (2D) materials, due to their extremely thin nature, eliminating detrimental substrate effects such as serious degradation of charge-carrier mobility or light-emission yield remains a major challenge. However, previous approaches have suffered from limitations such as structural instability or the need of costly and high-temperature deposition processes. Herein, we propose a new strategy based on the insertion of high-density topographic nanopatterns as a nanogap-containing supporter between 2D materials and substrate to minimize their contact and to block the substrate-induced undesirable effects. We show that well-controlled high-frequency SiO nanopillar structures derived from the self-assembly of Si-containing block copolymer securely prevent the collapse or deformation of transferred MoS and guarantee excellent mechanical stability. The nanogap supporters formed below monolayer MoS lead to dramatic enhancement of the photoluminescence emission intensity (8.7-fold), field-effect mobility (2.0-fold, with a maximum of 4.3-fold), and photoresponsivity (12.1-fold) compared to the sample on flat SiO. Similar favorable effects observed for graphene strongly suggest that this simple but powerful nanogap-supporting method can be extensively applicable to a variety of low-dimensional materials and contribute to improved device performance.

Surface microstructuring of polymer electrolyte membranes (PEMs) has been considered as an effective strategy to extend the three-phase boundary in PEM fuel cells (PEMFCs). However, it is still unclear which parameters are the most critical for maximizing cell performance. In this study, in order to elucidate the correlation between the membrane surface topography and PEMFC performances, we employed solvent-assisted nanotransfer printing and plasma deep etching techniques, which allow independent control of structural parameters. This approach enables the formation of various catalyst–membrane interface structures with controlled pattern periods and aspect ratios. Our systematic customization reveals that nanowell patterned membranes partially filled with carbon-supported platinum (Pt/C) can significantly improve fuel cell performance, which is driven by both reducing kinetic resistance and mass transport resistance. In particular, the sample with a pattern period of 1200 nm and a well depth of 1100 nm exhibited the best performance, a current density of 1000 mA/cm2 at a cell voltage of 0.6 V, and a maximum power density of 583 mW/cm2. These values are 53 and 41% higher than those with unpatterned membranes, respectively, at the same Pt loading.