Nanowerk July 26, 2023 Over the past few decades, considerable advances have been achieved in polymer electrolyte membrane fuel cells (PEMFCs) based on the development of material technology. Recently, an emerging multiscale architecting technology covering nanometer, micrometer, and millimeter scales has been regarded as an alternative strategy to overcome the hindrance to achieving high-performance and reliable PEMFCs. In their review article researchers in South Korea provided summaries of progress in the key components of PEMFCs based on a novel architecture strategy. In the first section, diverse architectural methods for patterning the membrane surface with random, single-scale, and multiscale structures as […]
Tag Archives: S&T South Korea
Researchers develop a current collector for energy storage devices with high-efficiency and long cycling life
Nanowerk June 21, 2023 Researchers in South Korea used to prepare floating catalyst–chemical vapor deposition-derived CNT sheets for potential use as all-around current collectors in two representative energy storage devices: batteries and electrochemical capacitors. CNT-based current collectors enhance ion transport kinetics and provide many ion adsorption and desorption sites, which are crucial for improving the performance of batteries and electrochemical capacitors. They demonstrated high-performance lithium-ion hybrid capacitors (LIHCs) by assembling activated carbon–CNT cathodes and prelithiated graphite–CNT anodes. CNT-based LIHCs exhibit 170% larger volumetric capacities, 24% faster rate capabilities, and 21% enhanced cycling stabilities relative to LIHCs based on conventional metallic […]
Breaking through the limits of stretchable semiconductors with molecular brakes that harness light
Science Daily June 9, 2023 Researchers in South Korea investigated the effects of an azide photocrosslinker’s molecular length and structure on the microstructural, electrical features, and stretchability of photocrosslinked conjugated polymer films. For a systematic comparison, they synthesized a series of nitrene-induced photocrosslinkers (n-NIPSs) with different numbers of ethylene glycol repeating units (n = 1, 4, 8, 13) that bridge two tetrafluoro-aryl azide end groups. Two semicrystalline conjugated polymers and two nearly amorphous conjugated polymers were co-processed with n-NIPSs and crosslinked by brief exposure to UV light. They found that among the synthesized n-NIPSs, the shortest one (1-NIPS) is the […]
Researchers find a way to reduce the overheating of semiconductor devices
Science Daily June 1, 2023 Researchers in South Korea experimentally demonstrated boosted in-plane thermal conduction by surface plasmon polaritons (SPPs) propagating along a thin Ti film on a glass substrate. Due to the lossy nature of metal, SPPs could propagate over centimeter-scale distances even along a supported metal film, and the resulting ballistic heat conduction could be quantitatively validated. For a 100-nm-thick Ti film on a glass substrate, a significant enhancement of in-plane thermal conductivity compared to bulk value (∼25%) was experimentally shown. According to the researchers their work will provide a new avenue to employ SPPs for heat dissipation […]
Newly developed hydrogel nanocomposite for the mass production of hydrogen
Phys.org April 27, 2023 Despite recent progress in designing highly active photocatalysts, inefficient solar energy and mass transfer, the instability of catalysts and reverse reactions impede their practical large-scale applications. Storing solar energy in chemical bonds aided by heterogeneous photocatalysis is desirable for sustainable energy conversion. Researchers in South Korea designed a floatable photocatalytic platform constructed from porous elastomer–hydrogel nanocomposites. The nanocomposites at the air–water interface featured efficient light delivery, facile supply of water and instantaneous gas separation. Consequently, a high hydrogen evolution rate of 163 mmol h–1 m–2 was achieved using Pt/TiO2 cryoaerogel, even without forced convection. When fabricated in an area […]
Revolutionary battery technology to boost EV range 10-fold or more
Science Daily March 29, 2023 High-capacity anode materials are promising candidates for increasing the energy density of lithium (Li)-ion batteries due to their high theoretical capacities. However, a rapid capacity fading due to the huge volume changes during charge-discharge cycles limits practical applications. Researchers in South Korea developed a layering-charged polymeric binder that could effectively integrate high-capacity anodes using a strong yet reversible Coulomb interaction and enriched hydrogen bonding. The charged polymeric binder built a dynamically charge-directed network on the active materials with high versatility and efficiently dissipated the electrode stress with mechanical properties. In addition, poly(ethylene glycol) (PEG) moieties […]
Carbon fiber paper for longer-lasting electric vehicle batteries
Nanowerk March 27, 2023 Researchers in South Korea have designed and constructed a hierarchical surface on carbon fiber (CF) using binders in fabricated CF paper (CFP). The lightweight CF with high mechanical properties established a 3D network structure as an alternative to Cu foil. The binders were transformed into oxygen-containing amorphous carbon and sodium carbonate (Na2CO3) using a low-temperature carbonization process which to uniform Li nucleation and a stable solid electrolyte interphase layer with inorganic components. In tests CFP with amorphous carbon and Na2CO3 (ANCFP) showed a low Li nucleation overpotential and smooth dendrite-free Li plating. The ANCFP electrode exhibited […]
Imaging through random media using coherent averaging
Phys.org March 7, 2023 Although methods to recover the Fourier amplitude through random distortions are well established, recovery of the Fourier phase has been a more difficult problem. Researchers in South Korea proposed and demonstrated a new phase retrieval method for imaging through random media. They showed that by ensemble averaging shift-corrected images, the Fourier phase of an object obscured by random distortions can be accurately retrieved up to the diffraction limit. The method is simple, fast, does not have any optimization parameters, and does not require prior knowledge or assumptions about the sample. The feasibility and robustness of the […]
Researchers fabricate novel flexible supercapacitors on paper
Nanowerk March 6, 2023 Paper’s inherent characteristics can be exploited to overcome the limitations of conventional substrates, such as weak adhesion and large mass densities. Researchers in South Korea proposed a method for fabricating vertically integrated multi-electrodes within only a single sheet of paper. Despite the randomly distributed fibrous networks in paper, the multi-layered electrodes were uniformly formed and completely separated by applying a removable hydrophobic wax barrier confinement inside a single sheet of paper. Conventional two-dimensional planes can be used as three-dimensional scaffolds. The highly integrated electrodes and circuit systems were located within a sheet of paper, making a […]
Scientists observe ‘quasiparticles’ in classical systems for the first time
Phys.org January 26, 2023 The concept of quasiparticles has become a cornerstone of condensed quantum matter, where it explains a variety of emergent many-body phenomena such as superfluidity and superconductivity. Researchers in South Korea used quasiparticles to explain the collective behaviour of a classical system of hydrodynamically interacting particles in two dimensions. In the disordered phase of this matter, measurements revealed a subpopulation of long-lived particle pairs. Modelling and simulation of the ordered crystalline phase identified the pairs as quasiparticles, emerging at the Dirac cones of the spectrum. The quasiparticles stimulated supersonic pairing avalanches, bringing about the melting of the […]