Advanced Powder Materials最新文献

The ever-growing demands for renewable energy sources motivate the development of energy storage systems. Among them, supercapacitors are received increasing attention due to their high power density, long cycle life, fast recharge rate, and almost no maintenance. Nevertheless, their application is hindered by severe self-discharge behaviors, especially in wearable and energy storage devices. In recent years, tremendous excellent works have been reported to conquer this shortcoming through various creative strategies. Herein, we gives a timely spotlight on breakthroughs in the self-discharge mechanism investigations of supercapacitors and the corresponding suppression strategies. The self-discharge mechanisms of various supercapacitors were introduced first, followed by a summary of the strategies from materials (i.e., electrode, electrolyte, and separator) to system and protocol optimization, furthermore, the connection between them, existing issues, and possible directions for future research are discussed.

The formation of balling, porosity and cracking defects is a vital obstacle in selective laser melting of wrought Al alloys. However, it lacks systematic research on the origins of these imperfections. Herein, the formation mechanisms and avoidance methods of metallurgical defects in slective laser melting (SLM)-processed Al–Cu–Mg alloy were investigated by numerical simulation and microstructure characterization. Process optimization by altering laser energy density can effectively suppress balling and porosity, thus enhancing relative density. Cracking results from the stress concentration and columnar grains arise due to the rapid cooling process during SLM. The methods that promote the columnar-to-equiaxed grain transition, such as microalloying by Sc/Zr/Ti elements, co-incorporation of ceramic particles and introducing ultrasound, can effectively enhance the cracking resistance and mechanical properties of wrought Al alloys.

How to improve the stability and processability of organic-inorganic hybrid perovskite quantum dots (OHPQD) is an important topic in recent research. In this work, the stability and machinability of OHPQD were improved by blending with PU elastomer. The CsPbBr₃−PU composites can be achieved easily by pouring molding process with rather excellent humidity and thermal stability. The tensile strength of 14 ​MPa and elongation of 580% at break of PU/CsPbBr₃ elastomer composites with self-repair properties were obtained, which was attributed to the introduction of disulfide bonds. It lays a foundation for the application of OHPQD.

In this short review, we highlight instances where interstitials have been shown to substantially increase the yield strength and work-hardening rate (WHR) of f.c.c. alloys, particularly high entropy alloys, medium entropy alloys, TWIP steels and stainless steels. However, the common practice of describing interstitial strengthening in f.c.c. alloys using models that are used to explain substitutional strengthening appears to be neither appropriate nor accurate. Here we suggest, based on the literature, that the yield strength increase due to interstitials in f.c.c. alloys is more appropriately described by a linear dependence on the concentration: due to a paucity of experimental studies, the dependence of the yield strength and WHR on misfit parameters is currently unclear. Thus, the source of the strengthening remains unclear. A feature that has been observed in several f.c.c. alloys is that interstitial additions lead to a change from wavy to planar slip although the origin of this change, which may be related to changes in stacking fault energy as well as other factors, remains unclear. The paper concludes by outlining areas of future research, including the need to develop a new model for interstitial strengthening in f.c.c. alloys.

Single-atom photocatalysts (SAPCs) have attracted great interests due to their remarkable atom utilization efficiency, excellent activity, and selectivity, yet no application in synchronous biorefinery and water splitting. Here, efficient SAPCs based on atomically dispersed Zn atoms on carbon nitride (named Zn−mCN) were produced. Experiments verified that Zn−mCN has widened adsorption range of visible-light and lowered ability of electron−hole recombination, leading to excellent photocatalytic redox activity for synchronous biorefinery and water splitting to co-produce lactic acid (selectivity up to 91.0%) and hydrogen (∼15898.8 ​μmol ​g⁻¹ ​h⁻¹). This system has excellent universality for small- molecule monosaccharides and macromolecular xylan. Poisoning experiments showed that h⁺, ¹O₂, ·O₂⁻ and ·OH can promote the simultaneous production of lactic acid and hydrogen. This work realized full utilization of whole redox reaction and provided a novel strategy for efficient and concomitant production of hydrogen and value-added chemicals from biomass-derived feedstocks aqueous solutions.

Electrodes in new function-flexible optoelectronic devices, need to meet the requirements of foldability and high transmittance. In last decades, thousands of research about copper and silver nanowires promoted the prosperity of photovoltaic industry. In this paper, we focus on the recent progresses of silver and copper nanowires for high transparent solar cell application, including preparation and optimization techniques. In addition, the primary obstacles of nanowire transparent electrodes in perovskite solar cells, organic solar cells and dye sensitized solar cells were discussed. Finally, the application prospects of nanowire-based high transparent solar cells were outlined.

Recently, the limited abundance and uneven geographical distribution of Li resources seriously hamper the growing demand for lithium-based energy storage devices. In this regard, potassium-ion batteries (KIBs) sharing similar “rocking chair” working principles with lithium-ion batteries have started to attract increasing attention due to their high energy density and abundant potassium resources. Carbon material is considered to show great potential for using as high-performance anode in KIBs. However, it is still a challenge to simultaneously achieve satisfactory specific gravimetric and volumetric capacities, high initial Coulombic efficiency, superior rate performance, and excellent cycle stability due to the sluggish reaction kinetics of the large-sized K-ions. Herein, we summarize the latest research achievements of different types of carbon anodes for KIBs, including graphite, graphene, hard carbon, soft carbon, and carbon nanotubes, in which the key factors affecting the electrochemical performance are explored. Importantly, the alternative strategies for addressing the low gravimetric/volumetric capacity and low initial Coulombic efficiency of carbons are thoroughly emphasized. Finally, the critical issues, challenges, and perspectives are proposed to show the development direction of KIBs. We hope this review can provide researchers with new ideas to design high-performance carbon materials and give insightful perspectives to accelerate the application of carbon electrodes for KIBs.