Moonjung Park

Elemental sulfur is one of the most attractive cathode active materials in lithium batteries because of its high theoretical specific capacity. Despite the positive aspect, lithium-sulfur batteries have suffered from severe capacity fading and limited rate capability. Here we report facile large-scale synthesis of a class of organosulfur compounds that could open a new chapter in designing cathode materials to advance lithium-sulfur battery technologies. Porous trithiocyanuric acid crystals are

We establish a new systematic methodology for controlling the water retention of polymer electrolyte membranes. Block copolymer membranes comprising hydrophilic phases with widths ranging from 2 to 5 nm become wetter as the temperature of the surrounding air is increased at constant relative humidity. The widths of the moist hydrophilic phases were measured by cryogenic electron microscopy experiments performed on humid membranes. Simple calculations suggest that capillary condensation is import

Phase behavior of poly(styrenesulfonate-methylbutylene) (PSS-PMB) block copolymers was studied by varying molecular weight, sulfonation level, and temperature. Molecular weights of the copolymers range from 2.9 to 117 kg/mol. Ordered lamellar, gyroid, hexagonally perforated lamellae, and hexagonally packed cylinder phases were observed in spite of the fact that the copolymers are nearly symmetric with PSS volume fractions between 0.45 and 0.50. The wide variety of morphologies seen in our copoly

The key challenges in the advancement of actuator technologies related to artificial muscles include fast-response time, low operation voltages and durability. Although several researchers have tackled these challenges over the last few decades, no breakthrough has been made. Here we describe a platform for the development of soft actuators that moves a few millimetres under 1 V in air, with a superfast response time of tens of milliseconds. An essential component of this actuator is the single-

We report the facile synthesis of new naphthoquinone ( NQ ) derivatives for use in lithium-organic batteries to improve performance. The rational design of these NQ derivatives is based on theoretical calculations. Our lithium-organic batteries demonstrate remarkable charge–discharge properties, for example, a high discharge capacity of 250 mAh g –1 (363 mAh cm –3 ), discharge potential plateaus in the range of 2.3–2.5 V, and 99% capacity retention after 500 cycles at 0.2 C . In particular, the

The effect of alignment of proton-conducting domains in hydrated poly(styrenesulfonate- b -methylbutylene) copolymer films on conductivity was studied by impedance spectroscopy. Pressing isotropic samples obtained by casting results in lamellae aligned in the plane of the film. Application of electric fields and flow fields on the isotropic samples results in lamellae aligned perpendicular to the plane of the film. The alignment of lamellae, quantified by a combination of two dimensional small a

Abstract The global energy crisis and an increase in environmental pollution in the recent years have drawn the attention of the scientific community towards the development of efficient electrochemical devices. Polymers containing charged species have the potential to serve as electrolytes in next‐generation devices and achieving high ion transport properties in these electrolytes is the key to improving their efficiency. In this article, we explore ways to improve the ion transport properties

Abstract Pressing challenges facing future lithium batteries include the realization of a high specific capacity, reliable cycle life, fast charging, and improved safety. Herein, cutting‐edge lithium–sulfur batteries based on sulfur‐rich polymers that demonstrate a high discharge capacity of 1346 mAh g −1 at 0.1C, a record‐high rate performance of 833 mAh g −1 at 10C, and long lifetime of 500 cycles with a low capacity decay of 0.052% per cycle are reported. These are realized via the linker‐con

A new method to develop two-dimensional PANI nanosheets using ice as a removable hard template is presented. Distinctly high current flows of 5.5 mA at 1 V and a high electrical conductivity of 35 S cm(-1) were obtained for the polyaniline (PANI) nanosheets, which marked a significant improvement from previously values on other PANIs reported over the past decades. These improved electrical properties of ice-templated PANI nanosheets were attributed to the long-range ordered edge-on π-stacking o

We have investigated a new means to control the morphology and conductivity of block copolymer electrolytes by the inclusion of ionic units at the chain ends. A set of poly(styrene- b -ethylene oxide) (PS-b-PEO) block copolymers having dissimilar PEO end groups (−OH, −SO 3 H, and −SO 3 Li) exhibited various self-assembled morphologies including disordered, lamellar, and hexagonal cylindrical phases. Strikingly, the addition of Li salts to PS-b-PEO with sulfonate terminal groups afforded enriched

We have developed fast responsive, colorimetric and resistive-type polymeric humidity sensors from a series of self-assembled poly(styrenesulfonate-methylbutylene) (PSS-b-PMB) block copolymers with tailored hygroscopic properties. In dry state, the PSS-b-PMB films exhibit hexagonal cylindrical morphology where hydrophobic PMB cylinders are dispersed within a PSS matrix. Under levels of humidity, the PSS-b-PMB thin films self-displayed discernible reflective color changes, covering almost entire

Soft actuators based on electroactive polymers (EAPs) are the core constituents of future soft robots owing to their fascinating properties such as lightweight, compactness, easy fabrication into various forms, and low cost. Ionic EAP actuators are particularly attractive owing to the low driving voltages (<3 V) as compared to those of electronic EAP actuators (usually kilovolts). This paper presents a brief overview of the recent progress in a range of EAP actuators by focusing on low voltage o

The current goal in functional polymeric material research is the preparation of polymers with high-fidelity nanoscale self-assembled structures and advanced functionality. Thus, recent research efforts have focused on linking chemistry for the development of tailor-made polymers with desired properties. The design of alpha- or omega-functionalized telechelic polymers with strongly associative interactions is connected to their unique supramolecular self-assembly behavior in homopolymers and ble