Phys.org November 11, 2022 Eliminating grain boundaries (GBs) is a primary approach to resisting high-temperature creep in metals which is responsible for component failures at high temperatures. Researchers in China found that grain boundaries in the nanograined single-phased alloy could be effectively stabilized through structural relaxation, and the creep performance of the alloy could be significantly enhanced at elevated temperatures. They demonstrated a creep resistance, with creep rates of ~10–7 per second under gigapascal stress at 700°C (~61% melting point), outperforming that of conventional superalloys. They plan to extend this principle to other engineering alloy families for high-temperature applications, including […]
Tag Archives: S&T China
One-unit-cell thick semiconductors with room-temperature magnetism
Nanowerk November 15, 2022 Researchers in China have developed a confined-van der Waals epitaxial approach to synthesizing air-stable semiconducting cobalt ferrite nanosheets with thickness down to one unit cell using a facile chemical vapor deposition process. They demonstrated hard magnetic behavior and magnetic domain evolution by means of vibrating sample magnetometry, magnetic force microscopy and magneto-optical Kerr effect measurements, which showed high Curie temperature above 390 K and strong dimensionality effect. According to the researchers their work provides possibilities for numerous novel applications in computing, sensing and information storage…read more. Open Access TECHNICAL ARTICLE
Putting the brakes on lithium-ion batteries to prevent fires
Science Daily November 14, 2022 Researchers in China have developed a kind of novel shape-memorized current collector (SMCC), which can successfully brake battery thermal runaway at the battery internal overheating status. Unlike traditional current collectors made of commercial copper foils, SMCC is made of a micropatterned shape memory micron-sized film with copper deposition. SMCC displays ideal conductivity at normal temperatures and turns to be insulative at overheating temperatures. According to the researchers a battery consisting of an SMCC can run normally at temperatures lower than 90 °C, while it quickly achieves self-shutdown before the occurrence of battery combustion and explosion…read […]
Novel copper gas penetration electrode can efficiently reduce CO2 to multicarbon products
Phys.org November 8, 2022 Although considerable progress has been made in CO2 electroreduction, sustained production of multicarbon compounds at high current density remains a challenge. Researchers in China reported a hierarchical micro/nanostructured Cu(100)-rich copper hollow fiber as a gas penetration electrode (GPE) that reduces CO2 to C2+ product with a faradaic efficiency of 62.8% and a current density of 2.3 A cm-2 in 0.5 M KHCO3 solution at −1.94 V (vs. RHE). Electrochemical results demonstrate that optimized mass transfer and enhanced three-phase interface reaction synergistically promote CO2 activation and reduction kinetics. Theoretical calculations suggested that the Cu(100) facet of Cu […]
Functional carbon materials for addressing dendrite problems in metal batteries
Phys.org October 25, 2022 Metal batteries that directly use active metals as anodes are promising solutions for energy upgrade of battery technologies, but they suffer from dendrite problems. Researchers in China have demonstrated that functional carbon materials (FCMs) can suppress metal dendrites. They reviewed recent progress in using FCMs to deal with dendrite problems. The review focused on the surface chemistry and multi-dimensional carbon material engineering, which systematically overcomes the problems through diverse methods, such as reinforcing desolvation, improving interface compatibility, homogenizing electric field, buffering volume expansion and lattice mismatch. They refined the long-standing debate about whether surface defects in […]
Mussel-inspired dynamic poly(disulfides) ultra-strong underwater adhesives
Phys.org October 18, 2022 Researchers in China have developed a simple and robust strategy that combines natural thioctic acid and mussel-inspired iron-catechol complexes to enable ultra-strong adhesive materials that can be used underwater and simultaneously exhibit unprecedented high adhesion strength on diverse surfaces. Their experimental results showed that the robust crosslinking interaction of the iron-catechol complexes as well as high-density hydrogen bonding were responsible for the ultra-high interfacial adhesion strength. The embedding effect of the hydrophobic solvent-free network of poly(disulfides) further enhanced the water-resistance. The network also made possible the resulting materials reconfigurable, thus enabling multiple reusability via repeated heating […]
Researchers develop novel robust superhydrophobic coating
Phys.org October 18, 2022 Fragile hierarchical structures, fluorine-containing chemicals usage, and strict requirements for substrate scopes in biomimetic superhydrophobic coating remain thorny challenges. Researchers in China constructed a mechanical robust superhydrophobic ZnO@STA@PDMS coating with fluorine-free reagents through wide-applicable and substrate-independent spray-coating method. Different analyses and contact angle meter were used to assess the surface micro-nano structures, chemical compositions, thermal stability, and wettability variations. The corrosion resistance of the coating was reduced by two orders of magnitude after being spray-coated with superhydrophobic ZnO@STA@PDMS indicating excellent corrosion resistance in marine submerged zone. In simulated marine atmospheric conditions with high relative humidity, the […]
New weather prediction model produces more accurate typhoon intensity forecasts
Phys.org October 12, 2022 Researchers in China cycled and evaluated western North Pacific (WNP) typhoons of 2016 using Kalman filter (EnKF) combined with the Advanced Research Weather Research and Forecasting model (WRF). For all TC categories, the 6-h ensemble priors from the WRF/EnKF system had an appropriate amount of variance for TC tracks but had insufficient variance, they overestimated the intensity for weak storms but underestimated the intensity for strong storms. Comparison with the 5-d deterministic forecasts compared to the NCEP [US] and ECMWF [European] operational control forecasts showed that the WRF/EnKF forecasts generally had larger track errors than the […]
Flexible solid electrolytes for all-solid-state lithium batteries
Phys.org October 3, 2022 The thick electrolyte layer and rigid nature as well as poor interfacial contact of doped garnet-type solid electrolytes are obstacles for its application in all-solid-state lithium batteries. Through solvent-free procedure researchers in China developed an ultrathin flexible Li6.4La3Zr1.4Ta0.6O12- (LLZTO-) based solid electrolyte with 90 wt% LLZTO. The resulting film exhibited ultrahigh ionic conductance of 41.21 mS at 30°C, excellent oxidation stability of 4.6 V, superior thermal stability and nonflammability. The assembled Li||LiFePO4 pouch cell with integrated electrolyte/cathode interface exhibited excellent rate performances and cycle performances with a capacity retention of 71.4% from 153 mAh g-1 to 109.2 mAh g-1 at 0.1 C […]
Researchers fabricate miniaturized bionic ocean-battery
Phys.org September 30, 2022 Researchers in China fabricated a bio-solar cell consisting of a four-species microbial community by mimicking the ecological structure of marine microbial ecosystems. The four-species microbial community was assembled into a spatial-temporally compacted cell using conductive hydrogel as a sediment-like anaerobic matrix, forming a miniaturized bionic ocean-battery. The battery directly converts light into electricity with a maximum power of 380 μW. It stably operated for over one month. They demonstrated such ecological structure consisting of primary producer, primary degrader, and ultimate consumers is essential for achieving high power density and stability. According to the researchers the photoelectric conversion […]