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Remarkable Li-ion battery(LIB) anode materials need to have long cycle life and fast charge/discharge rate, however they are difficult to be realized in the monolayer anode materials. The monolayer β-Bi has the stiffness of only 33.0 N/m, thus the Bi/G heterostructure is proposed to improve the electronic and mechanical properties and to produce better LIB anode performance in this paper. The calculated results show that Bi/G heterostructure has excellent thermodynamic, dynamical and mechanical stability. The band gap is only 0.04 eV, which ensures remarkable electrical conductivity. In addition, the Bi/G heterostructure has higher stiffness (369.2 N/m) than that of monolayer β-Bi and graphene. The diffusion barrier (Ebarrier) of 0.32 eV and volume expansion ratio(VER) of only 4% can ensure the rapid transport of Li+ ions in the charge/discharge cycling process and long life of the LIB. These calculated theoretical results for describing the detail properties of Li storage and diffusion in the Bi/G heterostructure can supply adequate conclusive evidence for the prediction of remarkable properties of Bi/G heterostructure as an anode material for LIBs.

Summary Preparation of thermally stable metal single-atom catalysts (SACs) is a challenge in heterogeneous catalysis, especially on conventional supports that provide a weak metal-support interaction. In this work, we report that a modified support MgAl2O4 can stabilize Pt single atoms by a mechanism of vapor-phase self-assembly in a high-temperature treatment (800°C, air). The experimental results on the formation mechanism and the structure are validated by DFT and ab initio molecular dynamics simulations. We infer that stable triangular K3O3 structures help stabilize Pt single atoms at high temperatures in oxidizing conditions, exhibiting excellent reactivity for methane oxidation. The obtained Pt/K/MgAl2O4 SAC presents excellent stability in methane oxidation after steam treatment at elevated temperatures, whereas the Pt/MgAl2O4 nanocatalyst suffers from rapid deactivation due to Pt nanoparticle growth. This work paves the way for preparing thermally stable and highly active SACs using conventional high-surface-area supports, despite the weak metal-support interaction.

Machining performance of thin-walled components made by aeronautical difficult-to-process materials is a significant issue in the aviation manufacturing industry. Although wire electric discharge machining-low speed (WEDM-LS) is one of typical non-contact machining processes without macro cutting force, which does well in removing hardness and brittleness materials via pulsed discharge at high temperature, but few researchers have studied the thermal distortion behavior leading to a considerable geometric error in the WEDM-LS of thin-walled components. In this paper, a transverse magnetic field assisted method is applied for affecting the uniformity of discharge point distribution so as to reduce the distortion in WEDM-LS processing thin-wall component. First, the generation mechanism of this new distortion behavior and the impact mechanism of transverse magnetic field (TMF) on distortion are demonstrated by theoretical analysis. In order to further figure out the distortion behavior in the TMF-WEDM process, a new thermo-physical model considering the discharge point distribution is established to simulate temperature field, residual stress field and distortion profiles. Then a large number of Taguchi experiments are carried out to investigate the influences of process parameters including pulse discharge energy (pulse on time, pulse off time, and current) and magnetic field strength on distortion in WEDM-LS. To comparatively analyze simulated and experimental results, the accuracy of established thermo-physical model is verified within a relative error of 18.38 % in distortion. Moreover, it can be revealed that transverse magnetic field contribute to significantly improve the longitudinal distribution uniformity with maximum increase of 12.32% at magnetic field strength: 0.15 T, leading to significant reductions of 32.77% in distortion and 22.68% in recast layer. Eventually, we also presented the variation of residual stress and recast layer along thickness direction under different distortion behavior, which are in good agreement with that of distortion behavior.

The entropy-driven monolayer assembly of hexagonal prisms and cylinders was studied under hard slit confinement. At the conditions investigated, the particles have two distinct and dynamically disconnected rotational states: unflipped and flipped, depending on whether their circular/hexagonal face is parallel or perpendicular to the wall plane. Importantly, these two rotational states cast distinct projection areas over the wall plane that favor either hexagonal or tetragonal packing. Monte Carlo simulations revealed a re-entrant melting transition where an intervening disordered Flipped-Unflipped (FUN) phase is sandwiched between a fourfold tetratic phase at high concentrations and a sixfold triangular solid at intermediate concentrations. The FUN phase contains a mixture of flipped and unflipped particles and is translationally and orientationally disordered. Complementary experiments were conducted with photolithographically fabricated cylindrical microparticles confined in a wedge cell. Both simulations and experiments show the formation of phases with comparable fraction of flipped particles and structure, i.e., the FUN phase, triangular solid, and tetratic phase, indicating that both approaches sample analogous basins of particle-orientation phase-space. The phase behavior of hexagonal prisms in a soft-repulsive wall model was also investigated to exemplify how tunable particle–wall interactions can provide an experimentally viable strategy to dynamically bridge the flipped and unflipped states.

Statement of problem Although studies have reported on selective laser melting (SLM)-fabricated removable partial dentures (RPDs), research addressing the trueness of SLM-fabricated RPD metal frameworks is sparse. Purpose The purpose of this in vitro study was to evaluate the trueness of powdered cobalt-chromium (Co-Cr) or titanium-6 aluminum-4 vanadium (Ti-6Al-4V) alloy frameworks for RPDs fabricated by SLM. Material and methods A digital scan of a Kennedy class II mandible typodont was obtained to design an RPD framework by using a computer-aided design (CAD) software program (denoted as CRF). Two experimental groups of frameworks were fabricated from the CRF by using SLM in alloys of Co-Cr (SLM-Co-Cr, n=6) and in Ti-6Al-4V (SLM-Ti-6Al-4V, n=6) while a control group was fabricated by using traditional lost-wax casting following stereolithography (CA-Co-Cr, n=6). In total, 18 RPD frameworks were digitally scanned (denoted as CRF), with each scan then superimposed on the CRF and evaluated for discrepancies by using a 3D analysis software program. A nonparametric Kruskal-Wallis test was performed to determine differences in trueness among groups (α=.05). Results The CA-Co-Cr group showed the highest discrepancy between CEF and CRF. Statistically significant differences were found between the CA-Co-Cr and SLM-fabricated groups (P=.03 for Co-Cr, and P=.016 for Ti-6Al-4V). However, no significant difference was found between the SLM-Co-Cr and SLM-Ti-6Al-4V groups (P=.787). Conclusions SLM-fabricated RPD frameworks exhibited higher trueness than CA-Co-Cr fabricated ones, indicating the potential of selective laser melting to produce the geometric shapes required for accurate dental restorations.

Owing to their high surface area, stable structure and easy fabrication, composite nanomaterials with encapsulation structures have attracted considerable research interest as sensing materials to detect volatile organic compounds. Herein, a hydrothermal route is designed to prepare foam shaped α-MoO3@SnS2 nanosheets that exhibit excellent sensing performance for triethylamine (TEA). The developed sensor, based on α-MoO3@SnS2 nanosheets, displays a high response of 114.9 for 100 ppm TEA at a low working temperature of 175 °C with sensitivity higher than many other reported sensors. In addition, the device shows a wide concentration detection range (from 500 ppb to 500 ppm), good stability after exposure to air for 80 days, and excellent selectivity. The superior sensing characteristics of the developed sensor are attributed to the high crystallinity of α-MoO3/SnS2, excessive and accessible active sites provided by the good permeability of porous SnS2 shells, and the excellent conductivity of the encapsulation heterojunction structure. Thus, the foam shaped α-MoO3@SnS2 nanosheets presented herein have promising practical applications in TEA gas sensing devices.

Single-atom catalysts (SACs) exhibit high catalytic activities in many systems including metal–air batteries. However, the fundamental catalytic mechanism of SACs during the charge/discharge process is still unclear. Herein, we report a real-time imaging of the microscopic evolution of single-atom Co/reduced graphene oxide (SA-Co/rGO) in Na–O2 nanobatteries via an in situ environmental transmission electron microscope. Clearly, Na2O2 spheres were formed on the surface of the SA-Co/rGO scaffold during discharging, which can be easily decomposed during charging. In contrast, the formation and decomposition of Na2O2 on bare rGO without SACs were very sluggish. Moreover, a coin cell Na–O2 battery with an SA-Co/rGO air cathode also displays superior performance to a bare rGO cathode. DFT calculations reveal that the local coordination environment (Co + 4N) played a key role in tuning the charge density and oxidation states of the isolated Co active sites, thus activating O2 molecules and facilitating the oxygen reduction reaction/oxygen evolution reaction processes. This study suggests that SA-Co/rGO may be a promising catalyst for enhancing the performance of Na–O2 batteries.

NASICON-type solid electrolyte Li1.3Al0.3Ti1.7P3O12 (LATP) is attractive because of the cheap raw materials, excellent air stability, and high ionic conductivity. Silicon doping is generally adopted to improve its conductivity further, but the corresponding mechanism is vacant. Herein, we synthesize the silicon doped LATP electrolyte with a simple solution-based method and systemically investigate the effects of different silicon doping level on the local structure, microstructure and ionic diffusion kinetics of the solid electrolytes. We firstly put forward the octahedral occupation of silicon in Li1.3Al0.3Ti1.7P3O12 electrolyte instead of tetrahedral sites. Silicon doping is found to be negative for the ionic transportation in grain bulk, however, the grain boundary conductivity can be increased after a small amount of silicon doping due to the modification of micro-structure, i, e., the silicon doping induces the segregation of LiTiOPO4 in the grain boundary, which can effectively suppress the abnormal growth of electrolyte grains and concomitant gas pores and cracks during sintering. As a result, the total conductivity can reach ∼10−3 S⋅cm−1 after silicon doping with this simple method. Our results demonstrate the critical importance of adjusting secondary phase on the micro-structure and ionic conductivity of electrolyte during the development of inorganic fast ionic conductors.

In the field of interface science, superwettability and photocatalysis are two significant research hot spots. Currently, wettability has been proved to be a decisive factor to enhance photocatalyt...

International audience; Layered cathode materials are commonly used in lithium and sodium ion batteries, but they are prone to degradation under electrochemical cycling during battery operation. Here we report a new type of degradation mechanism through the electrochemically induced mechanical buckling and delamination cracking of intercalation layers in a P2 Na0.7-Ni0.3Mn0.6Co0.1O2 (Na-NMC) cathode material. Kinks form in the delaminated layers due to severe local bending, and each kink consists of a vertical array of dislocations, resulting from an easy slip between transition metal oxide layers. In situ mechanical compression experiments directly reveal the kink formation due to strong mechanical anisotropy parallel and perpendicular to the intercalation layers in single-crystal Na-NMC. In situ electrochemical experiments indicate that kinks form during the desodiation process. Our results unveil a new mechanism of electrochemically induced mechanical degradation stemming from weak interlayer bonding in layered cathode materials. This work has broad implications for the mitigation of degradation associated with irreversible interlayer slip in layered cathode materials.

The treatment of emissions from natural gas engines is an important area of research since methane is a potent greenhouse gas. The benchmark catalysts, based on Pd, still face challenges such as water poisoning and long-term stability. Here we report an approach for catalyst synthesis that relies on the trapping of metal single atoms on the support surface, in thermally stable form, to modify the nature of further deposited metal/metal oxide. By anchoring Pt ions on a catalyst support we can tailor the morphology of the deposited phase. In particular, two-dimensional (2D) rafts of PdOx are formed, resulting in higher reaction rates and improved water tolerance during methane oxidation. The results show that modifying the support by trapping single atoms could provide an important addition to the toolkit of catalyst designers for controlling the nucleation and growth of metal and metal oxide clusters in heterogeneous catalysts. Despite its importance in the context of natural gas engines emissions treatment, methane oxidation remains challenging. Now, the authors introduce an approach to stabilize PdOx rafts on ceria by trapping Pt single atoms in the support resulting in a superior catalyst for this transformation.

Sodium (Na) metal batteries (SMBs) using Na anode are potential “beyond lithium” electrochemical technology for future energy storage applications. However, uncontrollable Na dendrite growth has plagued the application of SMBs. Understanding Na deposition mechanisms, particularly the early stage of Na deposition kinetics, is critical to enable the SMBs. In this context, we conducted in situ observations of the early stage of electrochemical Na deposition. We revealed an important electrochemical Ostwald ripening (EOR) phenomenon which dictated the early stage of Na deposition. Namely, small Na nanocrystals were nucleated randomly, which then grew. During growth, smaller Na nanocrystals were contained by bigger ones via EOR. We observed two types of EOR with one involving only electrochemical reaction driven by electrochemical potential difference between bigger and smaller nanocrystals; while the other being dominated by mass transport governed by surface energy minimization. The results provide new understanding to the Na deposition mechanism, which may be useful for the development of SMB for energy storage applications.

The corrosion-promotion effect caused by the high conductivity of graphene (G) cannot meet the requirement of long-term protection of G-containing coating under the increasingly complex working condition. Herein, a multifunctional epoxy (MF) composite coating with multilayer structure is constructed containing bottom nano-Al2O3/epoxy layer, intermediate G/epoxy layer, and top nano-SiO2/epoxy layer via a layer-by-layer (LBL) assembly method to improve the corrosion resistance, UV resistance, and tribological properties. MF composite coating exhibits an improved impedance value increased by 10 times and the excellent long-term chlorine resistance, mainly depending on the formation of tortuous diffusion path and avoiding the galvanic corrosion between G and metal substrate. Its wear rate (1.59 × 10−7 mm3/N·mm) is decreased by 73.54% compared with pure epoxy coating due to the lubrication effect of nanofillers and the increase of coating crosslinking density. Moreover, the improved UV aging resistance is reflected in the unchanged chemical structure after 30 days of exposure in UV irradiation, which is attributed to the absorption and reflection of UV light by the nanofillers. Therefore, the as-prepared multifunctional coating has great application prospects in materials protection.

The high cost of platinum (Pt)-group metal (PGM)-based catalysts used in proton-exchange membrane fuel cells (PEMFCs) poses a critical roadblock to their widespread adoption. Although using low PGM loading PEMFCs can largely address this challenge, high current density performance will be severely compromised consequently. To overcome this dilemma, we report the development of ultra-thin platinum-cobalt nanowires (PtCoNWs) as the cathode catalysts for ultralow Pt loading and high-performance membrane electrode assembly (MEA). The PtCoNWs delivered a record-high mass activity (MA) of 1.06 ± 0.14 AmgPt−1 of Pt-alloy catalysts towards oxygen reduction reaction (ORR) in MEA, yielding an impressive total Pt utilization of 5.14 WratedmgPt−1. The PtCoNWs retained a respectable end-of-life MA of 0.45 A mgPt−1 after the 30,000 cycles square-wave accelerated stability test, which is still above the Department of Energy 2020 beginning-of-life target for catalysts. In-situ X-ray absorption spectroscopy studies suggest that the high degree of alloying in the PtCoNWs stabilizes the ultrathin structure and may contribute to the high ORR activity and power density performance in PEMFC.

The emerging carbon-based mesoscopic perovskite solar cells (MPSCs) are known as one of the most promising candidates for photovoltaic applications thanks to their screen-printing process and excellent stability. Unfortunately, they usually suffer from serious defects because it is challenging to realize sufficient mesopore filling of the perovskite precursor solution throughout the triple-mesoporous scaffold. Herein, a bifunctional additive, biuret, endowed with both carbonyl and amino groups, was designed to realize a convenient fabrication approach for controllable crystallization of the precursor solution. Owing to the strong coordination ability with perovskite components, the incorporation of biuret can not only regulate crystallization kinetics allowing for the growth of high-quality perovskite crystals but also associate with uncoordinated ions for defect passivation to enhance the overall photovoltaic performance of MPSCs. A champion power conversion efficiency (PCE) of 13.42% with an enhanced short-circuit current density of 19.49 mA cm-2 and a much higher open-circuit voltage of 0.96 V was achieved for the device doped with 3 mol % biuret, which is 26% higher than that of the control device (10.66%). Moreover, the unencapsulated devices with biuret incorporation demonstrated superior stability, maintaining over 90% of the original PCE after 50 days of storage under ambient conditions. This work helps exploit bifunctional additive strategies for simultaneous defect passivation and crystallization control toward high-efficiency and long-term stability of carbon-based MPSCs.

The two biggest promises of solid-state lithium (Li) metal batteries (SSLMBs) are the suppression of Li dendrites by solid-state electrolyte (SSE) and the realization of a high-energy-density Li anode. However, LMBs have not met their expectations due to Li dendrite growth causing short-circuiting. In fact, Li dendrites grow even more easily in SSE than in liquid electrolyte, but the reason for this remains unclear. Here we report in situ transmission electron microscopy observations of Li dendrite penetration through SSE and "dead" Li formation dynamics in SSLMBs. We show direct evidence that large electrochemomechanical stress generates cracks in the SSE and drives Li through the SSE directly. We revealed that fresh Li nucleation sites emerged in every discharge cycle, creating new "dead" Li in the following charging cycle and becoming the dominant Coulombic efficiency decay mechanism in SSLMBs. These results indicate that engineering flaw size and reducing electronic conductivity in SSEs are essential to improve the performance of SSLMBs.

The development of pressure sensor arrays capable of distinguishing the shape and texture details of objects is of considerable interest in the emerging fields of smart robots, prostheses, human-machine interfaces, and artificial intelligence (AI). Here we report an integrated pressure sensor array, by combining solution-processed two-dimensional (2D) MoS2 van der Waals (vdW) thin film transistor (TFT) active matrix and conductive micropyramidal pressure-sensitive rubber (PSR) electrodes made of polydimethylsiloxane/carbon nanotube composites, to achieve spatially revolved pressure mapping with excellent contrast and low power consumption. We demonstrate a 10 × 10 active matrix by using the 2D MoS2 vdW-TFTs with high on-off ratio > 106, minimal hysteresis, and excellent device-to-device uniformity. The combination of the vdW-TFT active matrix with the highly uniform micropyramidal PSR electrodes creates an integrated pressure sensing array for spatially resolved pressure mapping. This study demonstrates that the solution-processed 2D vdW-TFTs offer a solution for active-matrix control of pressure sensor arrays, and could be extended for other active-matrix arrays of electronic or optoelectronic devices.

High interfacial resistance and uncontrollable lithium (Li) dendrite are major challenges in solid-state Li-metal batteries (SSLMBs), as they lead to premature short-circuiting and failure of SSLMBs. Here, we report the synthesis of a composite anode comprising a three-dimensional LiCux nanowire network host infiltrated with Li (Li* anode) with low interfacial impedance and superior electrochemical performance. The Li* anode is fabricated by dissolving Cu foil into molten Li followed by solidification. The Li* anode exhibits good wettability with Li6.4La3Zr1.4Ta0.6O12 (LLZTO) and high mechanical strength, rendering low Li*/LLZTO interfacial impedance, homogeneous deposition of Li, and suppression of Li dendrites. Consequently, the Li* anode-based symmetric cells and full cells with LiNi0.88Co0.1Al0.02O2 (NCA), LiFePO4 (LFP), and FeF2 cathodes deliver remarkable electrochemical performance. Specifically, the Li*/LLZTO/Li* symmetrical cell achieves a remarkably long cycle lifetime of 10 000 h with 0.1 mA·cm-2; the Li*/LLZTO/NCA full cell maintains capacity retention of 73.4% after 500 cycles at 0.5C; and all-solid-state Li*/LLZTO/FeF2 full cell achieves a reversible capacity of 147 mAh·g-1 after 500 cycles at 100 mA·g-1. This work demonstrates potential design tactics for an ultrastable Li*/garnet interface to enable high-performance SSLMBs.

Considering laser power, defocus length, and welding speed, a Taguchi experiment (25 groups) was designed to investigate the 30-kW-laser-welding processing of 16-mm-thick marine steel EH40. The fusion zone (FZ) microstructure was martensite, whereas the microstructure of the base metal (BM) was ferrite and pearlite. The microstructure of the heat-affected zone (HAZ) near the FZ was martensite, and that near the BM was martensite and ferrite. It was found that a large size (width, depth, and depth-width ratio), low hardness, and weak corrosion resistance can be easily obtained under a high laser power and low welding speed. The welding speed was a major factor affecting the weld width, and the effects of laser power and defocus length were small. The influence of laser welding, welding speed, and defocus length on the weld depth increases successively. Owing to the martensite phase in the weld, the hardness of the FZ and most of the HAZ (519-647 HV) was more than twice that of the BM (255 HV). The hardness of most of the HAZ was higher than that of the FZ because of a decrease in grain size. The corrosion resistance was found to become weaker for the same reason.

Morphology transformation and crystal growth strategies of metal oxide semiconductors are extensive studied in material science recently, because the morphology and crystallinity of the nanomaterial have significant effect on the physicochemical characteristics. However, understanding the morphology changes of α-MoO3 induced by annealing temperature is still a challenge. Herein, the nanostructure transition of MoO3 induced by calcined temperature has been investigated through XRD and SEM method. It can be found that crystallization is highly dependent on the annealing temperature. In addition, the MoO3 nanoflowers can change into nanosheets at 500 ºC. Afterwards, the nanosheets turn into microrods, especially at 900 ºC due to the growth of MoO3 crystal. On the other hand, MoO3 is a traditional sensing material, which is sensitive to many volatile organic compounds. Thus, the sensing performances of various MoO3 nanostructures were measured. Compared with MoO3 nanoflowers and microrods. The MoO3 nanosheets based sensor has excellent sensing performance towards ethanol, and the maximum gas response value is 8.06.

Infection is one of the major reasons which induce failure of percutaneous Ti implants. Covalent bonding of antimicrobial peptides (AMPs) on Ti surfaces can avoid AMPs' blast release by physical absorption, but the reduced mobility affects their antibacterial efficiency. In this paper, HHC36 was pegylated with PEG12 and immobilized on hydroxyapatite (HA) nanorods to endow Ti surface with antibacterial activity and improved cytocompatibility simultaneously. The obtained results indicated that HA nanorods immobilized with HHC36 showed antibacterial activity, and pegylation obviously increased the antibacterial activity of immobilized HHC36 against staphylococcus aureus. They reached 99.5% and 97.0% in vitro and in vivo, respectively. PEG12 is flexible, and it increases mobility of HHC36 and enables lateral diffusion of peptide molecules into the lipid double layer of microbial membrane, resulting in highly antibacterial activity of HHC36. Furthermore, HA nanorods immobilized with pegylated HHC36 have reduced inflammatory response in an infection model and should be potentially applied on percutaneous Ti implants for reducing infection-induced failure and enhancing biointegration.

Flexible piezoelectric thin films are raising interest in energy harvesting and wearable electronics, although their direct fabrication is challenging in the selection of substrates and thermal processing. In this work, we developed direct fabrication of flexible lead-free (K, Na)NbO3 (KNN)-based piezoelectric films on commercially available metallic foils by sol-gel processing. Stainless steel and platinum foils are selected as flexible substrates because of their good thermal stability, robust flexibility, and cost-efficiency. The sol-gel-processed KNN-based thin films on both of the metallic foils show good flexibility, with the bending radii reaching ±3 mm. The flexible thin films grown on stainless steel and platinum foils present high breakdown electric fields that reach 1760 and 2530 kV/cm, respectively, resulting from the fine-grained dense structure, limited leakage current density, and suppressed mobility of charged carriers. Improved effective piezoelectric coefficient d33, eff* (75.4 pm/V) with a slight decrease after bending was obtained in the flexible thin films on Pt when compared to their rigid counterparts. The flexible lead-free piezoelectric thin films with combined high breakdown electric fields and piezoelectric and energy storage properties may pave the way for integrating KNN-based multifunctional thin films into flexible electronics.

The unique applications of porous metal-organic framework (MOF) liquids with permanent porosity and fluidity have attracted significant attention. However, fabrication of porous MOF liquids remains challenging because of the easy intermolecular self-filling of the cavity or the rapid settlement of porous hosts in hindered solvents that cannot enter their pores. Herein, we report a facile strategy for the fabrication of a MOF liquid (Im-UiO-PL) by surface ionization of an imidazolium-functionalized framework with a sterically hindered poly(ethylene glycol) sulfonate (PEGS) canopy. The Im-UiO-PL obtained in this way has a CO2 adsorption approximately 14 times larger than that of pure PEGS. Distinct from a porous MOF solid counterpart, the stored CO2 in Im-UiO-PL can be slowly released and efficiently utilized to synthesize cyclic carbonates in the atmosphere. This is the first example of the use of a porous MOF liquid as a CO2 storage material for catalysis. It offers a new method for the fabrication of unique porous liquid MOFs with functional behaviors in various fields of gas adsorption and catalysis.

The increasing demand for safe and dense energy storage has shifted research focus from liquid electrolyte-based Li-ion batteries toward solid-state batteries (SSBs). However, the application of SSBs is impeded by uncontrollable Li dendrite growth and short circuiting, the mechanism of which remains elusive. Herein, we conceptualize a scheme to visualize Li deposition in the confined space inside carbon nanotubes (CNTs) to mimic Li deposition dynamics inside solid electrolyte (SE) cracks, where the high-strength CNT walls mimic the mechanically strong SEs. We observed that the deposited Li propagates as a creeping solid in the CNTs, presenting an effective pathway for stress relaxation. When the stress-relaxation pathway is blocked, the Li deposition-induced stress reaches the gigapascal level and causes CNT fracture. Mechanics analysis suggests that interfacial lithiophilicity critically governs Li deposition dynamics and stress relaxation. Our study offers critical strategies for suppressing Li dendritic growth and constructing high-energy-density, electrochemically and mechanically robust SSBs.

A three-layered transmitting focusing gradient meta-surface (FGMS) has been proposed, which can achieve broadband gain enhancement from 8.2 GHz to 10 GHz. The element of broadband transmitting FGMS has high transmitting efficiencies that over 0.7 and achieve [0, 2π] phase range with a flat and linear trend in the operating band. The FGMS can transform the spherical waves into plane waves. Three patch antennas working at 8.2 GHz, 9.1 GHz, and 10 GHz respectively are placed the focus of broadband FGMS as the spherical-wave source to build a broadband planar lens antenna system. It achieves a simulation gain of 15.44 dBi which is 7.51dB higher than that of the bare patch antenna at 10 GHz with satisfying SLLs and beamwidths. However, it enhanced the gain of the bare patch antenna in a wide operating band. Finally, the FGMS and the patch antenna are fabricated and measured. The measured results are in good agreement with the simulations.

Aconitine and hypaconitine are the main active ingredients of Radix Aconiti, paeoniflorin and albiflorin are the primary components of Radix Paeoniae Alba. Both Radix Aconiti and Radix Paeoniae Alba are herbs that are commonly used in traditional Chinese medicine. This study sought to explore the mechanistic transport of aconitine and hypaconitine across MDCK-MDR1 cells and to assess the effect of paeoniflorin and albiflorin on aconitine and hypaconitine transmembrane transport as a potential attenuation mechanism. Drug cytotoxicity was tested via the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, and transport studies were performed in both directions. The effects of drugs on P-gp ATPase activity, P-gp efflux function, MDR1 mRNA and P-gp expression were evaluated in MDCK-MDR1 cells. Aconitine and hypaconitine treatment with the verapamil could significantly decrease the efflux rate (ER). The ER of aconitine and hypaconitine were significantly increased with the coadministration of paeoniflorin and albiflorin, suggesting that paeoniflorin and albiflorin can promote the efflux of these two alkaloids. Aconitine and hypaconitine can induce P-gp enzymatic activity, inhibit P-gp-mediated efflux, and downregulate the expression of P-gp protein to produce cytotoxic effects. When treatment in combination with paeoniflorin and albiflorin, it could stimulated P-gp ATPase activity, increasing mRNA expression, enhance P-gp efflux function, and upregulate P-gp protein expression.

Developing highly efficient electrochemical catalysts for carbon dioxide reduction reaction (CO2RR) provides a solution to battle global warming issues resulting from ever-increasing carbon footprint due to human activities. Copper (Cu) is known for its efficiency in CO2RR towards value-added hydrocarbons; hence its unique structural properties along with various Cu alloys have been extensively explored in the past decade. Here, we demonstrate a two-step approach to achieve intimate atomic Cu-Ag interfaces on the surface of Cu nanowires, which show greatly improved CO2RR selectivity towards methane (CH4). The specially designed Cu-Ag interfaces showed an impressive maximum Faradaic efficiency (FE) of 72% towards CH4production at −1.17 V (vs. reversible hydrogen electrode (RHE)).

Baffle system is a promising disaster mitigation measure, while the mechanism of debris-baffle interaction at grain scale has not been fully understood, and especially the effect of the unsteady nature of granular flow on debris-baffle interaction has not been detailly investigated. For this purpose, we conducted various small-scale model tests and used the three-dimensional discrete element method to assist the interpretation of the experimental results and extend research content. The granular arch that is formed between the baffle slit controls the debris-baffle interaction, which is completely different from the dead zone-dominant debris-barrier interaction mechanism represented by a rigid or flexible barrier. The particle size effect is controlled by the baffle jamming behavior. Larger particles facilitate the rapid formation of a stable force arch with larger energy-breaking efficiency. And flows with larger Froude number are not easy to form stable granular arches. Thus, the baffle array number, particle size, and construction site control the efficiency of baffle structure in deceleration of granular flows. Particularly, increasing the baffle array number restricts the recovery of flow mobility after the flow passes the baffle structure. In general, the construction of baffle at deposition area may not be an effective engineering options, because the impact force discrepancy on baffle array is larger by 28%, the generated energy dissipation is lower by 60.97%, the run-out distance by 10% and the spreading distance on the slope by approximately 40% for baffles in the deposition area compared with baffles constructed on slope.

Thermoplastic polyurethane (TPU) films have been widely used as substrates in the rapidly developing fields of flexible electronics and soft actuators. Patterned high-quality cutting is of great significance to the promotion of applications. In order to clarify the mechanism of laser cutting, Raman and thermal analyses were performed. Raman tests verified that no new solid by-products were produced after laser cutting. Thermal cracking and thermogravimetric-infrared combined analysis were used to simulate the process of nanosecond laser cutting, and the results showed that the gas by-products released were mainly composed of organic substances including ketone and phenol with benzene ring as the main body, as well as low-chain hydrocarbons and alcohols. Moreover, a cutting quality evaluation standard consists of cutting kerf zone (CKZ) and heat-affected zone (HAZ) was established. And based on this standard, the better nanosecond laser cutting parameters are 10 kHz and 0.03 m/s, which was obtained from a 2-factors and 5 levels orthogonal experiment. Main effect and interaction analysis were performed to clarify the impact of laser parameters on cutting quality and each other.

The combination of non-thermal plasma (NTP) and catalyst characterized by high energy efficiency, enhanced volatile organic compounds (VOCs) removal efficiency, high product selectivity, and low production of unwanted and/or toxic by-products possesses a great promise for the abatement of VOCs. This work reviews the state of knowledge regarding Mn-based catalysts for VOCs abatement in the post-plasma-catalytic (PPC) system. First, the development and the performance of different Mn-based catalysts such as pure manganese oxide, mixed manganese oxide-based catalysts, and supported Mn-based catalysts in terms of VOCs abatement and O3 decomposition are summarized. Then, the mechanism of the VOCs decomposition in the NTP and PPC system is discussed. Finally, the modeling and simulation of VOCs abatement in the NTP and PPC system are overviewed. This review aims at providing a reference guide for the development and optimization of VOCs abatement in the PPC system using Mn-based catalysts.

Surface engineering of quantum dots (QDs) plays critical roles in tailoring carriers’ dynamics of I-III-VI QDs via the interplay of QDs in aggregates or assembly, thus influencing their photocatalytic activities. In this work, an aqueous synthesis and the followed pH tuned oriented assembly method are developed to prepare network-like aggregates, dispersion, or sheet-like assembly of GSH-capped Silver Indium Sulfide (AIS). FTIR, DLS, and HRTEM investigation revealed that surface protonation or deprotonation of QDs occurred at pH 12 favors the formation of network-like aggregates with various defects or sheet-like assembly with perfect crystal lattice, respectively, via the surface charge induced interaction among AIS QDs. Further UV–vis, steady and transient PL investigation confirm the narrowed band gaps and the prolonged PL lifetime of the acidic network-like aggregates. As a result, the optimized network-like aggregates (3.0-AIS) exhibits superior photocatalytic H2 evolution (PHE) rates (5.2 mmol·g−1·h−1), about 113 times that of alkaline sheet-like assembly (13.0-AIS) or 2.7 times higher than that of dispersed AIS QDs (AIS-8.0). The formation of defects and their roles in PHE mechanisms are discussed. This work is expected to give some new insight for designing efficient non-cadmium/non-novel metal I-III-VI photocatalysts for boosting PHE.

Summary The scalable preparation of high-purity monolayers is essential for practically integrating two-dimensional (2D) semiconductors in diverse technologies but remains a persistent challenge. Previous efforts to exfoliate 2D layered crystals by the organic ammonium intercalation usually produce few-layer nanosheets owing to a self-retarding effect that hinders the complete intercalation in neighboring layers. Herein, we report a unique “intercalation and separation” chemistry with a constant self-refreshing crystal surface that mitigates the self-retarding effect to ensure a complete intercalation of the bulk crystal, ultimately enabling high-yield solution-phase exfoliation of 2D semiconductor monolayers in excellent purity (e.g., monolayer purity of >95% for In2Se3 and InSe). Furthermore, we have assembled large-area organic/inorganic hybrid superlattices with diverse organic molecules and inorganic 2D monolayer crystals, thus creating a family of artificial superlattice materials with atomically modulated chemical compositions, widely tunable superlattice periodicities, and specifically tailorable electronic and thermal properties.

Five closely spaced Au or Ag NPs are linearly arranged in analogy with Newton's cradle, forming various homogeneous and heterogeneous NP chains. Using small NPs, the Au–Ag–Ag–Ag–Au heterochain has the lowest propagation loss (17.6%) at short resonance wavelengths. When the NP diameter is increased to 80 nm, the dominant resonance is shifted to longer wavelengths. As low as 6% of the total energy dissipates in the intermediate NP component, and there seems to be little difference between the Au–Ag–Ag–Ag–Au heterochain and the Ag–Ag–Ag–Ag–Ag homochain. Besides the wavelength-dependent intrinsic loss (i.e., the imaginary part of the permittivity) in metals, the real part of the permittivity also plays a critical role in determining the propagation loss. Considering the high fabrication cost of the heterochain, the homochain composed of moderately large Ag NPs (

The development of eco-friendly and light-weighted solid-state electrolytes with a wide electrochemical window is critical to apply flexible energy storage devices for powering wearable and implantable electronics. Herein, we report the first demonstration of a quasi solid-state hydrogel electrolyte leveraging the formation of “interfacial wetting water” for facile two-dimensional ion transports instead of typical diffusion in bulk-like water. The hydrogel electrolyte exhibits a wide electrochemical window (2.5 V) in electrical double layer capacitance (EDLC) cell with an extremely effective low salt concentration (6.8 m), 3.1 times lower than the well-known water-in-salt electrolyte (WiSE, 21 m), and a small water retention (24 wt%). Besides, a significant toughness (ultimate tensile strength of 420 kPa and elongation of 6,000%) is achieved. The flexible supercapacitor demonstrates the high specific energy density of 39.1 Wh•kg−1 at 0.5 A•g−1 and 7.6 Wh•kg−1 at power density of 6218 W•kg−1, as well as a subdued self-discharge profile. This interfacial water dominated hydrogel electrolyte provides new directions in designing high-voltage hydrogel electrolyte for safe and sustainable soft energy storage devices.

Heat gain through glazing is a major source of the space cooling load in subtropical cooling-dominant climates. Application of energy-efficient glazing systems can significantly reduce the energy consumption of air conditioning in summer. Thus, it has become a popular research topic. In this study, a sample of silica aerogel glazing was developed and prepared. Two identical insulated boxes were then constructed; one faÇade was equipped with the aerogel glazing sample and the other was prepared with a conventional double-layer glazing. An onsite measurement of the boxes’ internal thermal properties was then conducted. The two boxes were placed within the same outdoor environment. The temperature, humidity, and enthalpy values were calculated with the boxes facing different orientations and in a variety of weather conditions. The performance of the silica aerogel glazing was then evaluated by both experimental and theoretical analysis. The results of this study will provide a basis for aerogel glass building application guidelines.

Ultraviolet (UVUV) nanosecond laser cutting of polyvinyl chloride (PVC) films was evaluated by experimental design and laser ablation principle. Factors such as laser power, cutting speed, and repe...

Rechargeable lithium-carbon dioxide (Li-CO2) batteries have attracted much attention due to their high theoretical energy densities and capture of CO2. However, the electrochemical reaction mechanisms of rechargeable Li-CO2 batteries, particularly the decomposition mechanisms of the discharge product Li2CO3 are still unclear, impeding their practical applications. Exploring electrochemistry of Li2CO3 is critical for improving the performance of Li-CO2 batteries. Herein, in-situ environmental transmission electron microscopy (ETEM) technique was used to study electrochemistry of Li2CO3 in Li-CO2 batteries during discharge and charge processes. During discharge, Li2CO3 was nucleated and accumulated on the surface of the cathode media such as carbon nanotubes (CNTs) and Ag nanowires (Ag NWs), but it was hard to decompose during charging at room temperature. To promote the decomposition of Li2CO3, the charge reactions were conducted at high temperatures, during which Li2CO3 was decomposed to lithium with release of gases. Density functional theory (DFT) calculations revealed that the synergistic effect of temperature and biasing facilitates the decomposition of Li2CO3. This study not only provides a fundamental understanding to the high temperature Li-CO2 nanobatteries, but also offers a valid technique, i.e., discharging/charging at high temperatures, to improve the cyclability of Li-CO2 batteries for energy storage applications.

Graphical abstract, Introduction Laser induced plasma micro-machining (LIPMM) has proved its superiority in micro-machining of hard and brittle materials due to less thermal defects, smaller heat affected zone and larger aspect ratio compared to conventional laser ablation. Objectives In order to improve characteristics and stability of induced plasma, this paper proposed magnetically controlled LIPMM (MC-LIPMM) to achieve a good performance of processing single-crystal silicon which is widely used in solid state electronics and infrared optical applications. Methods A comprehensive study on surface integrity and geometrical shape was conducted based on the experimental method. Firstly, the mechanism of MC-LIPMM including laser-plasma, laser-materials interactions and transport effects was theoretically analyzed. Then a series of experiments was conducted to completely investigate the effect of magnetic field intensity, pulse repetition frequency, and bubble behavior on surface integrity and geometrical shape of micro channels. Results It revealed that magnetic field contributed to maximum reduction of 12.64% for heat affected zone and 62.57% for width while maximum increase of 26.23% for depth and 90.26% for aspect ratio. Conclusion This research confirms that MC-LIPMM can improve the machining characteristics of silicon materials and cavitation bubbles shows an apparently negative impact on the surface morphology.

Recently, near-infrared (NIR) light-triggered photochemical reactions have been of particular interest owing to their potential in solar-driven chemistry and biomedical applications. However, asymm...

Developing advanced electrochemical double-layer supercapacitors (EDLCs) with high energy density and capacitance can be realized by exploring the electrodes possessing large specific surface area ...

Experiments were carried out to study the dynamic and thermal characteristics of rockslide motion using a model slope with sliding blocks of varying parameters. A high-speed camera for block velocity, an acceleration acquisition system for impact acceleration, and a thermal infrared camera for heating. The results between the recorded velocities and theoretical are consistent for sliding blocks. The impact acceleration shows complex non-stationary characteristics over a very short time duration (~ 0.01 s), high amplitude (up to 5 g measured near the impact point), high-frequency motion (generally 100–300 Hz), and rapid attenuation. The thermal infrared images show that impact heating is substantially higher than frictional heating. The thermal analysis indicates frictional heating of 1–4.6 °C, whereas impact heating reached 20–60 °C. The temperatures during sliding were affected by the velocity, contact stiffness, and mass of the sliding block, with velocity showing the strongest influence. The impact heat dissipated very rapidly: 80% dissipated within 2 s, 95% within 5 s, and 98% within 10 s. The results of this study can be used as a future reference, and the impact characteristics provide guidelines for the development of disaster prevention measures. Moreover, the high temperatures verified in the tests provide meaningful information for studies on the sliding surface and movement speed of landslides.

The isothermal curing kinetics of polymethacrylimide/nano-SiO2 composites were investigated using a dynamic thermomechanical analysis. The relative conversion was defined with the storage modulus. The Avrami model-fitting method, Friedman method and integral method were applied to analyze the curing kinetics. The storage modulus and loss modulus increased appreciably, spanning three orders of magnitude throughout the curing. The frequency correlation of the relative conversion was noticeable at 180 °C because the glass transition took place when the curing degree was not high enough. The Avrami model-fitting analysis gave good fits for the experimental data. The activation energy calculated with the Avrami equation changed from 65.46 kJ/mol to 25.28 kJ/mol at 180–190 °C, while at 190–200 °C, the activation energy changed from 107.14 kJ/mol to 63.82 kJ/mol. The model-free analysis revealed the dependence of the activation energy on the relative conversion. The activation energy increased from 104.3 kJ/mol to 130.6 kJ/mol with the use of the Friedman method when the relative conversion ranged between 0.4–0.8. Similarly, the activation energy calculated with the integral method increased from 71.5 kJ/mol to 103.4 kJ/mol. When the relative conversion exceeded 0.8, the activation energy decreased gradually. The mobility of the reactive groups was hindered and the crosslinking density of the composite was much higher. The curing kinetics became diffusion controlled. The activation energy of the PMI/SiO2 composite was greater than that of PMI, which could be attributed to the hindrance effect caused by nano-SiO2.

Developing transition-metal nanocatalysts with precious-metal-like ability is essential for complete mineralization of formaldehyde (HCHO) at room temperature. Herein, a series of N-doped carbon en...