Science Daily August 23, 2021 Mg/S batteries are some of the most promising rechargeable batteries owing to their high theoretical energy density. However, their development is hindered by low electronic conductivity of S, sluggish Mg2+ diffusion in solid Mg–S compounds formed by discharge, and dissolubility of polysulfides into electrolytes. To address these problems researchers in Japan proposed liquid-S/sulfide composite cathode materials in combination with an ionic liquid electrolyte at intermediate temperatures (∼150 °C). The composite structure is spontaneously fabricated by electrochemically oxidizing metal sulfides, yielding liquid S embedded in a porous metal-sulfide conductive frame. They demonstrated the concept by a […]
In a first, scientists capture a ‘quantum tug’ between neighboring water molecules
Phys.org August 25, 2021 An accurate description of the ultrafast vibrational motion of water molecules is essential for understanding the nature of hydrogen bonds and many solution-phase chemical reactions. An international team of researchers (USA – SLAC National Accelerator Laboratory, UC Davis, University of Nebraska, Stanford University, Sweden) measured the ultrafast structural response to the excitation of the OH stretching vibration in liquid water with femtosecond temporal and atomic spatial resolution using liquid ultrafast electron scattering. They observed a transient hydrogen bond contraction of roughly 0.04 Å on a timescale of 80 femtoseconds, followed by a thermalization on a timescale of […]
An innovative process prevents irreversible energy loss in batteries
Phys.org August 24, 2021 Due to the permanent loss of Li ions that occurs during the initial charge in the stabilization stage of the battery production the theoretical energy density that can be stored in the batteries has not been achieved. To overcome this issue researchers in South Korea have developed an electrode pre-treatment solution capable of minimizing the initial Li ion loss in graphite-silicon oxide composite anodes. After being dipped in the solution, the anode, which was composed of 50% SiOx, demonstrated negligible Li loss, enabling a full cell to exhibit near-ideal energy density. The work highlights the promise […]
Laser scribed graphene for supercapacitors
Nanowerk August 23, 2021 Supercapacitors, which have safe and fast charge (in seconds) and high energy storage are promising for consumer electronics, hybrid electric vehicles and industrial power management. Recently, laser scribed graphene has been increasingly studied for supercapacitor applications. With the laser scribing process, graphene can be directly fabricated and patterned for supercapacitors. Researchers in China summarize recent developments, current challenges and future advancements of supercapacitors based on laser scribed graphene. They summarize facile laser scribing methods for graphene and the application for electrochemical double-layer capacitors, pseudo-capacitors, and hybrid supercapacitors. Recent developments are discussed demonstrating that laser scribing technology […]
Lightweight composite material inspects itself: Changes in color indicate deformations
Science Daily August 23, 2021 An international team of researchers (Switzerland, UK) developed a new type of laminate that changes color as soon as the material is deformed. The laminate is composed of alternating layers of a plastic polymer and artificial nacre or mother-of-pearl and is modelled on the biological example of the mussel shell. It consists of glass platelets arranged in parallel, which are compacted, sintered, and solidified using a polymeric resin making it extremely hard and break-resistant. The second layer consists of a polymer and an indicator molecule synthesised specifically for this application. The molecule is activated as […]
New Exotic Magnetic Quasiparticle: “Skyrmion Bundle” Joins Topological Zoo
SciTech Daily August 23, 2021 Although theory has proposed “skyrmion bags” and “high-order skyrmions” as multi-Q topological magnetic structures, their experimental observations remain elusive. Using 3D micromagnetic simulation approach, an international team of researchers (China, USA – University of New Hampshire) proposed a new 3D multi-Q topological structure, skyrmion bundle. Through experimental verification they found collective motions and topological sign dependence of Hall sideway shifts of skyrmion bundles driven by nanosecond pulsed currents. Skyrmion bundles can serve as information carriers applied in distinct spintronic devices such as multi-state memory and information interconnect and should pave a new field of topological […]
New form of carbon in a mesh tantalizes with prospects for electronics
Nanowerk August 27, 2021 Biphenylene network is highly conductive and may prove able to store more electrical energy than even graphene. However, their syntheses remain challenging given the lack of reliable protocols for generating nonhexagonal rings during the in-plane tiling of carbon atoms. An international team of researchers (Germany, Finland, Japan) has grown an ultraflat biphenylene network with periodically arranged four-, six-, and eight-membered rings of sp2-hybridized carbon atoms through an on-surface interpolymer dehydrofluorination (HF-zipping) reaction. The characterization of this biphenylene network by scanning probe methods reveals that it is metallic rather than a dielectric. They expect the interpolymer HF-zipping […]
New insulation material provides more efficient electricity distribution
Phys.org August 26, 2021 One way to reduce transmission loses such as this is by increasing the direct current voltage level. However, an increase in the transmission voltage adversely affects the insulation of an HVDC cable. An international team of researchers (Sweden, Italy) have shown that by adding very small amounts of the conjugated poly(3-hexylthiophene) (P3HT), it is possible to lower the electrical conductivity by up to three times. The work opens new possibilities for manufacturers. The researchers believe that their discovery could lead to numerous new applications and directions for research…read more. Open Access TECHNICAL ARTICLE
A new platform for integrated photonics
Phys.org August 25, 2021 The quality of photonic integrated circuits are limited due to the high density of crystal defects near growth interface. Researchers in China have fabricated an ultralow loss 4H-SiCOI platform with a record-high-Q factor of 7.1 × 106. The platform was prepared by wafer-bonding than thinning techniques, enabled the same crystalline quality as bulk high-pure 4H-SiC crystal. The high Q resonators were used to demonstrate various nonlinear processes including generation of multiple harmonics up to the fourth order. Broadband frequency conversions, including second-, third-, fourth- harmonic generation have been observed. Using a dispersion-engineered SiC microresonator, Kerr frequency […]
New quantum ‘stopwatch’ can improve imaging technologies
Phys.org August 24, 2021 Time-correlated single-photon counting (TCSPC) is an enabling technology for applications such as low-light fluorescence lifetime microscopy and photon counting time-of-flight (ToF) 3D imaging. However, state-of-the-art TCSPC single-photon timing resolution (SPTR) is limited to 3–100 ps by single-photon detectors. Researchers at the University of Colorado experimentally demonstrated a time-magnified TCSPC (TM-TCSPC) that achieves an ultrashort SPTR of 550 fs with an off-the-shelf single-photon detector. It can resolve ultrashort pulses with a 130-fs pulse width difference at a 22-fs accuracy. When applied to photon counting ToF 3D imaging, the it greatly suppresses the range walk error that limits […]