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One of the challenges in the semiconductor industry is to find new barrier materials and copper (Cu) alternative solutions in interconnects. In this work, we focused to find alternative diffusion barrier materials. Different binary (CoMo, CoRu, CoTa, CoW, MoRu, RuTa, RuW) and ternary (CoMoTa, CoRuTa, MoRuTa) metal alloys were evaluated theoretically with the Miedema model to find the amorphous phase composition range. Afterward, thin films of the alloys with various compositions were deposited by magnetron sputtering and theoretical values were compared to the experimental results. From the experimental measurements, which included grazing incidence x-ray diffraction analysis and resistivity measurements, suitable binary and ternary alloys were chosen for diffusion analysis. By annealing thin film stacks at temperatures ranging from 500 to 675 ° C, diffusion was induced and detected by x-ray photoelectron spectroscopy depth profiles. Seventeen alloys were evaluated by their diffusion barrier effectiveness, and five of those, which include Ru 60 Ta 40 , Ru 45 W 55 , Mo 47 Ru 53 , Mo 36 Ru 50 Ta 14 , and Co 40 Mo 35 Ta 25 , showed excellent barrier properties against copper diffusion. Furthermore, all of the stated materials have a lower resistivity than TaN. Last, the adhesion of the best performing alloys to SiCOH and Cu was evaluated by the modified edge lift-off test. Only Ru 45 W 55 had reasonable adhesion at both interfaces. The other materials showed low adhesion strength to Cu, which would make an adhesion promoter (liner), such as cobalt, necessary for the integration. [ABSTRACT FROM AUTHOR]

Uranium-based materials are valuable assets in the energy, medical, and military industries. However, understanding their sensitivity to hydrogen embrittlement is particularly challenging due to the toxicity of uranium and the computationally expensive nature of quantum-based methods generally required to study such processes. In this regard, we have developed a Chebyshev Interaction Model for Efficient Simulation (ChIMES) that can be employed to compute energies and forces of U and UH3 bulk structures with vacancies and hydrogen interstitials with accuracy similar to that of Density Functional Theory (DFT) while yielding linear scaling and orders of magnitude improvement in computational efficiency. We show that the bulk structural parameters, uranium and hydrogen vacancy formation energies, and diffusion barriers predicted by the ChIMES potential are in strong agreement with the reference DFT data. We then use ChIMES to conduct molecular dynamics simulations of the temperature-dependent diffusion of a hydrogen interstitial and determine the corresponding diffusion activation energy. Our model has particular significance in studies of actinides and other high-Z materials, where there is a strong need for computationally efficient methods to bridge length and time scales between experiments and quantum theory. [ABSTRACT FROM AUTHOR]

A layered sodium-ion battery cathode, O3/P3/P2-type NaNi1/3Mn1/3Fe1/3O2, has been systematically investigated by first-principles density functional theory to explore the detailed structural and Na-ion diffusion behavior during desodiation. Our results suggest that the (NaO6) spacing is greatest in the P3 phase and lowest in the O3 phase, with the P2 phase exhibiting intermediate spacing. During desodiation, the intermediate stages have a greater (NaO6) spacing than the initial and final stages. The great (NaO6) spacing facilitates the formation of the P3 phase, resulting in the structural evolution of NaxNi1/3Mn1/3Fe1/3O2 from the O3 to the P3 phase at x ≈ 0.59, finally reaching the O3 structure again at x ≈ 0.12. The electronic structure clearly proves that both Ni and Fe are active in O3/P3/P2-type NaxNi1/3Mn1/3Fe1/3O2. Ni2+ is oxidized to Ni3+ as Na content decreases from x = 1 to x = 0.66, then further oxidized to Ni4+ at x = 0.33, and finally, Fe3+ → Fe4+ oxidation occurs at x = 0. In the Na ion diffusion behavior, the order of the barrier is O3 (0.82 eV) > P2 (0.53 eV) > P3 (0.35 eV) at the initial stage, whereas it is O3 (0.53 eV) > P3 (0.21 eV) > P2 (0.16 eV) at a highly desodiated stage. The former can be traced back to the (NaO6) spacing, but the latter is related to the different Na sites. Our results thus provide a factor of the structural evolution and Na ion diffusion barrier by considering (NaO6) width and Na site changes during desodiation. [ABSTRACT FROM AUTHOR]

Copper (Cu) interconnections have been widely used in advanced electronic packaging due to their outstanding thermal and electric properties. Preparing a smooth and uniform Cu seed thin layer is one of the critical processes to obtain high-reliability Cu interconnections. The barrier layer between Cu and silicon (Si) devices is necessary to prevent the inter-diffusion between Cu and Si. However, little work has been done on the surface roughness analysis of the Cu seed layer deposited on the diffusion barrier layer. In this paper, the influences of deposition thickness, incident energy, barrier layer temperature, and surface morphology on the surface roughness of the Cu seed layer deposited on α-titanium (α-Ti) barrier layer were studied in detail by the molecular dynamics (MD). The simulation results indicated that appropriate parameters have a beneficial effect on reducing the surface roughness, and the surface morphology of the Cu seed layer strongly connects with that of the barrier layer. These results provided a foundation for optimizing the quality of the Cu seed layer. [ABSTRACT FROM AUTHOR]

Bimetallic, reactive multilayers are uniformly structured materials composed of alternating sputter-deposited layers that may be ignited to produce self-propagating mixing and formation reactions. These nanolaminates are most commonly used as rapid-release heat sources. The specific chemical composition at each metal/metal interface determines the rate of mass transport in a mixing and formation reaction. The inclusion of engineered diffusion barriers at each interface will not only inhibit solid-state mixing but also may impede the self-propagating reactions by introducing instabilities to wavefront morphology. This work examines the effect of adding diffusion barriers on the propagation of reaction waves in Co/Al multilayers. The Co/Al system has been shown to exhibit a reaction propagation instability that is dependent on the bilayer thickness, which allows for the occurrence of unstable modes in otherwise stable designs from the inclusion of diffusion barriers. Based on the known stability criteria in the Co/Al multilayer system, the way in which the inclusion of diffusion barriers changes a multilayer's heat of reaction, thermal conductivity, and material mixing mechanisms can be determined. These factors, in aggregate, lead to changes in the wavefront velocity and stability. [ABSTRACT FROM AUTHOR]

Adsorption, desorption, and diffusion dynamics of hydrogen gas molecules over a hexagonal ZnO monolayer have been studied thoroughly in the van der Waals Density Functional Theory (vdW-DFT) framework in association with kinetic Monte Carlo (kMC) simulations. Hydrogen molecules can attach to a ZnO sheet via a weak physisorption process with a limitation of maximum attachment of three molecules per hexagonal ring. Pressure and temperature are the main deciding parameters for the overall storage capacity of hydrogen on a ZnO substrate. kMC simulations are performed to capture the stochastic behavior of surface dynamics of gas molecules. Adsorption energy and diffusion barrier are predicted to be around 50–60 meV and 4–12 meV, respectively, according to vdW-DFT calculations. kMC simulations with these energy parameters estimate the surface coverage of hydrogen to be pretty high below room temperature and high pressure. Furthermore, the hydrogen adsorption in the ZnO monolayer leads to the increase of the bandgap value, subsequently changing the conductivity of the material. The present research work sheds light on the usage of a ZnO monolayer for suitable hydrogen gas storage and sensing applications. [ABSTRACT FROM AUTHOR]

Ultrashort period 1.0 nm W/Si multilayers have potential as dispersive Bragg reflectors in high-resolution x-ray fluorescence. However, formation of WSix leads to poor optical performance. To address this, we introduce ultrathin 0.1 nm B4C diffusion barriers in sputter-deposited 1.0 nm W/Si, inhibiting W–Si interaction. We demonstrate that the peak reflectance at a wavelength of 0.834 nm increased with a factor of 3.4 compared to W/Si. Diffuse scattering measurements reveal no change in interfacial roughness when applying B4C barriers compared to W/Si. X-ray reflectivity analysis shows a substantial increase in optical contrast between Si and W as well as sharper transitions between the layers. Chemical analysis suggests that the B4C barrier reduces formation of WSix through partial substitution of W-silicide bonds with W-carbide/boride bonds, leading to an increase in optical contrast. The resulting structure of W/Si with B4C barriers offers a compelling alternative to the more established W/B4C multilayer at the ultrashort scale due to its superior soft- and hard x-ray reflectance. [ABSTRACT FROM AUTHOR]

Ni/NiFe 2 coatings with different thickness of Ni were deposited on 50-h pre-oxidized SUS 430 steel by magnetron sputtering for solid oxide fuel cell (SOFC) interconnects application, which were subsequently exposed to 800 °C air for durations of up to 5040 h. Ni/NiFe 2 coating was thermally converted to an oxide structure comprising inner NiO layer and outer NiFe 2 O 4 spinel layer. The effects of different NiO diffusion barrier thickness on the oxidation behavior, electrical performance and long-term working stability of NiO/NiFe 2 O 4 coated steel were investigated. The chromium vaporization from bare and coated steels was also evaluated at 800 °C in air-12 % H 2 O atmosphere. Results showed that scale delamination and the spike of area specific resistance (ASR) were achieved for the sample with thicker NiO layer after 2520 h thermal exposure. Moreover, NiO gradually migrated outward through the solid-state reaction between NiO and NiFe 2 O 4 spinel and eventually aggregated near the outer surface. Breakaway oxidation of the bare steel occurred during the chromium vaporization test and undulating Fe oxide nodules were strewn on the steel surface. The chromium vaporization rate was effectively suppressed by the application of NiO/NiFe 2 O 4 coating. [ABSTRACT FROM AUTHOR]

Using the BVS method, we calculate Li-ion pathways and diffusion barriers in the interface between silicene and MgCl2, MgBr2 and MgI2 substrates and we show that the results are in good agreement with the previously published DFT studies. In addition, we showcase that BVS does not need the exact crystal structure as we examine different initial positions for the Li ion and different interface heights without affecting the calculated BVSE. Furthermore, we show that surface diffusion BVS calculations can be used to roughly optimize the interface, thus completely foregoing DFT geometry optimization calculations. Here, we propose that BVS can substitute DFT as a quick filter when searching for low migration barriers in silicene-based materials, providing good enough accuracy. [ABSTRACT FROM AUTHOR]

The discovery of novel electrode materials based on two-dimensional (2D) structures is critical for alkali metal-ion batteries. Herein, we performed first-principles computations to investigate functionalized MXenes, Mo2BT2 (T = O, S), which are also regarded as B-based MXenes, or named as MBenes, as potential anode materials for Li-ion batteries and beyond. The pristine and T-terminated Mo2BT2 (T = O, S) monolayers reveal metallic character with higher electronic conductivity and are thermodynamically stable with an intrinsic dipole moment. Both Mo2BO2 and Mo2BS2 monolayers exhibit high theoretical Li/Na/K storage capacity and low ion diffusion barriers. These findings suggest that functionalized Mo2BT2 (T = O, S) monolayers are promising for designing viable anode materials for high-performance alkali-ion batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] Na 3 V 2 (PO 4) 2 F 3 (NVPF), recognized for its Na superionic conductor architecture, emerges as a promising candidate among polyanion-type cathodes for sodium ion batteries (SIBs). However, its adoption in practical applications faces obstacles due to its inherently low electronic conductivity. To address this challenge, we employ a binary co-doped strategy to design Na 3.3 K 0.2 V 1.5 Mg 0.5 (PO 4) 2 F 3 cathode with nitrogen-doped carbon (NC) coating layer. This configuration enhances electronic conductivity and reduces diffusion barriers for sodium ion (Na+). The strategy of incorporating nitrogen-doped carbon coating not only facilitates the formation of a porous structure but also introduces additional defects and active sites. Such modifications accelerate the reaction kinetics and augment electrolyte interaction through an expanded specific surface area, thus streamlining the electrochemical process. Concurrently, strategic heteroatom substitution leads to a more efficient engagement of Na+ in the electrochemical activities, thereby bolstering the cathode's structural integrity. The vanadium fluorophosphate Na 3.3 K 0.2 V 1.5 Mg 0.5 (PO 4) 2 F 3 @NC exhibits an electrochemical performance, including a high discharge specific capacity of 124.3 mA h g−1 at 0.1C, a long lifespan of 1000 cycles with a capacity retention of 93.1 % at 10C, and a rate property of 73.2 mA h g−1 at 20C. This research provides a method for preparing binary doped NVPF for energy storage electrochemistry. [ABSTRACT FROM AUTHOR]

[Display omitted] • Compared with bulk NbSe 2 , few-layered wgef-NbSe 2 nanosheets presented shortened activation cycles, lower reaction polarization, better cyclic stability, and accelerated ion diffusion kinetics. • The continuous and intensive charge accumulation region between the NbSe 2 interlayers ensures a strong adsorption tendency of Na+ in virtue of forming a certain Coulombic force. • The interlayers possess a lower Na+ diffusion barrier, which is as low as 0.18 eV, guaranteeing NbSe 2 to achieve rapid reaction kinetics. • During the sodiation, Coulomb force causes the shrinkage of the d -spacing of some specific lattice planes of the NaNbSe 2 intermediate. However, the other planes are immune to the Coulomb force, showing the expansion of d -spacing. • Wgef-NbSe 2 exhibits an intercalation and conversion parallel running mechanism that promises the high structural robustness and high theoretical capacity. The unique superconductivity and charge density wave transition characteristics of NbSe 2 make it worthy of exploring its electrochemical performance and potential applications in the field of batteries. Herein, the bulk NbSe 2 was successfully exfoliated into few-layered NbSe 2 nanostructures by wet grinding exfoliation approach, which solved the issues of its long activation period and poor cycle stability. The strong Nb-Se bond in the plane and weak van der Waals force between the adjacent layers could render the fast Na+ diffusion, provide abundant reaction sites and multi-directional migration paths, thus accelerate the ionic conductivity. The theoretical calculations verified the high Na+ adsorption tendency between the NbSe 2 interlayers stemming from the continuous region of charge accumulation. Thanks to the unique electronic and two-dimensional few-layered structures, the exfoliated NbSe 2 exhibited a high cyclic stability with a capacity of 502 mA h g−1 over 2800 cycles at 10 A/g. In addition, the reaction mechanism was studied by in - situ X-ray diffraction and other tests, indicating a reaction mechanism containing of simultaneous intercalation (N b S e 2 ↔ N a x N b S e 2 ↔ N a N b S e 2 ↔ N a 1 + x N b S e 2) and conversion processes in NbSe 2. This parallelly running mechanism not only alleviates the volume change but also ensures a high specific capacity. Additionally, different lattice planes of the NaNbSe 2 intermediate in the intercalation process experience varying degrees of contraction and expanding in d -spacing due to the influence of Coulombic force. [ABSTRACT FROM AUTHOR]

At present, germanium (Ge) as a high-mobility material is considered as a possible replacement for Si in microelectronics. The main obstacle in the method is the large vacancy concentration obtained after the implantation of shallow donors. This prevents the formation of n + regions and has a negative impact on device performance. One way to eliminate the detrimental effects of such defects is through the codoping approach. In this study, the behavior of Na impurities in germanium together with the formation of defect complexes with vacancies, divacancies and shallow donors (P and As) were investigated using hybrid density functional theory calculations. The site preference, diffusion barriers, charge states and binding energies of various complexes, as well as the activation of donor–vacancy complexes with both F and Na codoping were investigated. For this purpose, two extreme cases were considered. Firstly, we calculate the concentrations of substitutional and interstitial Na together with monovacancies in the case of quasi-equilibrium conditions realized for doping from melt. Another extreme case is Na codoping during ion implantation. Our calculations show that Na passivates vacancies, divacancies and donor–vacancy complexes (E-centers) with a large energy gain, which prevents rapid donor diffusion similar to the case of doping with fluorine. We have shown that the passivation of E-centers with both F and Na impurities leads to the back transformation of such complexes into shallow donors. This means that codoping with Na may neutralize the harmful effects of vacancies and is a perspective for defect engineering. [ABSTRACT FROM AUTHOR]

In aqueous aluminum‐ion batteries (AAIBs), the insertion/extraction chemistry of Al3+ often leads to poor kinetics, whereas the rapid diffusion kinetics of hydronium ions (H3O+) may offer the solution. However, the presence of considerable Al3+ in the electrolyte hinders the insertion reaction of H3O+. Herein, we report how oxygen‐deficient α‐MoO3 nanosheets unlock selective H3O+ insertion in a mild aluminum‐ion electrolyte. The abundant oxygen defects impede the insertion of Al3+ due to excessively strong adsorption, while allowing H3O+ to be inserted/diffused through the Grotthuss proton conduction mechanism. This research advances our understanding of the mechanism behind selective H3O+ insertion in mild electrolytes. [ABSTRACT FROM AUTHOR]

In aqueous aluminum‐ion batteries (AAIBs), the insertion/extraction chemistry of Al3+ often leads to poor kinetics, whereas the rapid diffusion kinetics of hydronium ions (H3O+) may offer the solution. However, the presence of considerable Al3+ in the electrolyte hinders the insertion reaction of H3O+. Herein, we report how oxygen‐deficient α‐MoO3 nanosheets unlock selective H3O+ insertion in a mild aluminum‐ion electrolyte. The abundant oxygen defects impede the insertion of Al3+ due to excessively strong adsorption, while allowing H3O+ to be inserted/diffused through the Grotthuss proton conduction mechanism. This research advances our understanding of the mechanism behind selective H3O+ insertion in mild electrolytes. [ABSTRACT FROM AUTHOR]

Potassium‐ion batteries (PIBs) have favorable characteristics in terms of cell voltage and cost efficiency, making them a promising technology for grid‐scale energy storage. The rational design of suitable electrode materials on a theoretical basis, aiming at high power and energy density, is of paramount importance to bring this battery technology to the practical market. In this paper, a series of iron‐based compounds with different non‐metal anions are selectively synthesized to investigate the nature of kinetic differences induced by anionic modulation. A combination of experimental characterization and theoretical calculation reveals that iron phosphide, with its moderate adsorption energy (Ea) and lowest diffusion barrier (Eb), exhibits the best cycling and rate properties at low electrochemical polarization, which is related to the narrow Δd‐p band center gap that facilitates ion transfer. In addition, the optimization of the electrolyte formula results in the carbon‐supported iron phosphide anode running stably over 2000 cycles at 0.5 A g−1 and exhibiting a high rate capacity of 81.1 mAh g−1 at 2 A g−1. The superior electrochemical properties are attributed to the robust KF‐rich solid electrolyte interphase formed by the highly compatible KFSI in ethylene carbonate (EC)/diethyl carbonate (DEC) configuration. [ABSTRACT FROM AUTHOR]

[Display omitted] Li-rich layered oxides cathodes (LLOs) as the promising next-generation cathode materials can provide ultrahigh capacity and energy density due to their distinctive anionic redox chemistry. Unfortunately, severe interfacial side reactions, surface structural degradation and sluggish Li+ kinetics have resulted in low initial coulombic efficiency (ICE), capacity decay and poor rate performance, restricting their practical applications for high-energy–density lithium-ion batteries. Herein, Surface structure regulation strategy used as surface modified agent is proposed to activate the anionic redox chemistry via ammonium tungstate treatment. Experimental results showcase that dual coating layer spinel-like structure LiMn 2 O 4 and Li 2 WO 4 have been successfully constructed on the surface of LLOs. The surface spinel-like structure providing 3 D Li+ diffusion channels together with fast-ion conductive layer decrease the interfacial Li+ diffusion barrier and boost the fasting Li+ kinetics. In addition, the in-situ reconstruction layer can further alleviate the interfacial side reactions and reinforce the surface structural stability. As a result, the ICE of modified LLOs can be precisely increased from 74.71 % to 107.42 % with the adjustment of ammonium tungstate usage. Moreover, it delivers a high reversible capacity of 279.5 mAh/g at 0.1 C, as well as excellent rate capability with capacity of 147.2 mAh/g at 5 C. This work provides a significant reference for designing high-energy–density LLOs via surface structure regulation strategy. [ABSTRACT FROM AUTHOR]

SUMMARY: The increased soil salinity is becoming a major challenge to produce more crops and feed the growing population of the world. In this study, we demonstrated that overexpression of OsDIR55 gene enhances rice salt tolerance by altering the root diffusion barrier. OsDIR55 is broadly expressed in all examined tissues and organs with the maximum expression levels at lignified regions in rice roots. Salt stress upregulates the expression of OsDIR55 gene in an abscisic acid (ABA)‐dependent manner. Loss‐function and overexpression of OsDIR55 compromised and improved the development of CS and root diffusion barrier, manifested with the decreased and increased width of CS, respectively, and ultimately affected the permeability of the apoplastic diffusion barrier in roots. OsDIR55 deficiency resulted in Na+ accumulation, ionic imbalance, and growth arrest, whereas overexpression of OsDIR55 enhances salinity tolerance and provides an overall benefit to plant growth and yield potential. Collectively, we propose that OsDIR55 is crucial for ions balance control and salt stress tolerance through regulating lignification‐mediated root barrier modifications in rice. Significance Statement: Collectively, we propose that OsDIR55 is crucial for ions balance control and salt stress tolerance through regulating lignification‐mediated root barrier modifications in rice. [ABSTRACT FROM AUTHOR]

Heterojunctions in electrode materials offer diverse improvements during the cycling process of energy storage devices, such as volume change buffering, accelerated ion/electron transfer, and better electrode structure integrity, however, obtaining optimal heterostructures with nanoscale domains remains challenging within constrained materials. A novel in situ electrochemical method is introduced to develop a reversible CuSe/PSe p‐n heterojunction (CPS‐h) from Cu3PSe4 as starting material, targeting maximum stability in potassium ion storage. The CPS‐h formation is thermodynamically favorable, characterized by its superior reversibility, minimized diffusion barriers, and enhanced conversion post K+ interaction. Within CPS‐h, the synergy of the intrinsic electric field and P‐Se bonds enhance electrode stability, effectively countering the Se shuttling phenomenon. The specific orientation between CuSe and PSe leads to a 35° lattice mismatch generates large space at the interface, promoting efficient K ion migration. The Mott‐Schottky analysis validates the consistent reversibility of CPS‐h, underlining its electrochemical reliability. Notably, CPS‐h demonstrates a negligible 0.005% capacity reduction over 10,000 half‐cell cycles and remains stable through 2,000 and 4,000 cycles in full cells and hybrid capacitors, respectively. This study emphasizes the pivotal role of electrochemical dynamics in formulating highly stable p‐n heterojunctions, representing a significant advancement in potassium‐ion battery (PIB) electrode engineering. [ABSTRACT FROM AUTHOR]

Lipid polymers such as cutin and suberin strengthen the diffusion barrier properties of the cell wall in specific cell types and are essential for water relations, mineral nutrition, and stress protection in plants. Land plant-specific glycerol-3-phosphate acyltransferases (GPATs) of different clades are central players in cutin and suberin monomer biosynthesis. Here, we show that the GPAT4/6/8 clade in Arabidopsis thaliana, which is known to mediate cutin formation, is also required for developmentally regulated root suberization, in addition to the established roles of GPAT5/7 in suberization. The GPAT5/7 clade is mainly required for abscisic acid-regulated suberization. In addition, the GPAT5/7 clade is crucial for the formation of the typical lamellated suberin ultrastructure observed by transmission electron microscopy, as distinct amorphous globular polyester structures were deposited in the apoplast of the gpat5 gpat7 double mutant, in contrast to the thinner but still lamellated suberin deposition in the gpat4 gpat6 gpat8 triple mutant. Site-directed mutagenesis revealed that the intrinsic phosphatase activity of GPAT4, GPAT6, and GPAT8, which leads to monoacylglycerol biosynthesis, contributes to suberin formation. GPAT5/7 lack an active phosphatase domain and the amorphous globular polyester structure observed in the gpat5 gpat7 double mutant was partially reverted by treatment with a phosphatase inhibitor or the expression of phosphatase-dead variants of GPAT4/6/8. Thus, GPATs that lack an active phosphatase domain synthetize lysophosphatidic acids that might play a role in the formation of the lamellated structure of suberin. GPATs with active and nonactive phosphatase domains appear to have nonredundant functions and must cooperate to achieve the efficient biosynthesis of correctly structured suberin. [ABSTRACT FROM AUTHOR]

The best choice today for a realistic method of increasing the energy density of a metal-ion battery is to find novel, effective electrode materials. In this paper, we present a theoretical investigation of the properties of hitherto unreported two-dimensional B 3 C 5 and N 3 C 5 bilayer systems as potential anode materials for lithium-ion batteries. The simulation results show that N 3 C 5 bilayer is not suitable for anode material due to its thermal instability. On the other hand B 3 C 5 is stable, has good electrical conductivity, and is intrinsically metallic before and after lithium intercalation. The low diffusion barrier (0.27 eV) of Li atoms shows a good charge and discharge rate for B 3 C 5 bilayer. Moreover, the high theoretical specific capacity (579.57 mAh/g) connected with moderate volume expansion effect during charge/discharge processes indicates that B 3 C 5 is a promising anode material for Li-ion batteries. [ABSTRACT FROM AUTHOR]

ZrCo alloy is easily poisoned by impurity gases such as O2, CO, and CO2, resulting in a deterioration in hydrogen storage performance. In this study, we conducted a comprehensive investigation into the adsorption and dissociation characteristics of oxygen on the ZrCo(110) surface using first-principles calculations. Previous studies indicated that the anti-disproportionation properties of ZrCo alloy can be significantly improved by Hf substitution, but the effect of Hf doping on the anti-poisoning properties has not been reported. We also examined the effect of Hf doping on the adsorption, dissociation, and diffusion characteristics of oxygen. It is found that on the ZrCo(110) surface, O2 molecules are easily dissociated and then stably adsorbed at the hollow site. Oxygen atoms will fill the surface preferentially and then diffuse inward. The doping of Hf has an insignificant impact on the adsorption or dissociation behavior of oxygen in comparison to the pure ZrCo surface. However, a notable observation is that the doping of Hf resulted in a reduction in the diffusion barrier for oxygen from the surface to the subsurface by 0.61 eV. Consequently, our study suggests that doping Hf is not an advisable strategy for improving the ZrCo(110) surface's resistance to O2 poisoning because of improved oxygen permeability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Facile synthesis of anode material with organized structure. • Binary composite demonstrates better performance than its unitary counterpart. • In-situ XRD together with in-depth characterization reveals sodium ion storage. • DFT calculation verifies the sodium migration barrier. Sodium-ion batteries offer significant advantages in terms of low-temperature performance and safety. In this study, we present a straightforward synthetic approach to produce bimetallic selenide NiCoSe 2 nanoparticles grown on a three-dimensional porous carbon framework for application as anode materials in sodium-ion batteries. This unique architecture enhances reaction kinetics and structural stability. The three-dimensional interconnected porous carbon network establishes a continuous pathway of electronic conductive, while increasing specific surface area and mitigating volume expansion. Consequently, these features expedite ion transfer and enhance electrolyte interaction. Notably, compared to CoSe, NiCoSe 2 exhibits reduced ion transport distances and lower sodium diffusion barriers. Leveraging these attributes, NiCoSe 2 /N, Se co-doped carbon composite materials (NiCoSe 2 /NSC) demonstrate a high specific capacity of 320.8 mAh/g, even after 1000 cycles at 5.0 A/g, with a capacity retention rate of 85.1%. The study further delves into the revelation of the reaction mechanism and ion transport pathway through in-situ X-ray diffraction (XRD) analysis and theoretical calculations. The development of these anode materials is poised to pave the way for advancements in sodium-ion battery technology. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) van der Waals heterostructures (vdWHs) received intensive interest due to their amazing physical properties and broad applications in fields such as ultrasensitive sensors, transistors, and solar cells. Although remarkable progresses were achieved for the synthesis of 2D vdWHs, great challenges still remain for the easy preparation of 2D vdWHs because of the weak interlayer coupling. As a type of 2D semiconductor, the 2D SnSe film is particularly appealing for optoelectronic and thermoelectric devices because of its high thermoelectric and optoelectronic performance. However, the easy preparation of large-area and high-quality 2D SnSe films remains a great challenge. In this work, we proposed an approach to regulate the preparation of high-quality 2D vdWHs, which employed the polarization field of substrate as a key factor to control the diffusion barriers of the adsorbed Sn and Se atoms. Hexagonally stacking α-In2Se3 was selected as such polarized substrate because this substrate exhibits out-of-plane ferroelectricity with upward or downward polarized states at room temperature, and the two degenerated polarized states can be easily switched by applying an external electric field. It was revealed that the polarization field of α-In2Se3 can substantially influence the diffusion behavior of Sn and Se atoms on polarized α-In2Se3 substrate. So, the film growth property of SnSe film is sensitive to the polarization direction of In2Se3 substrate. Our research provides an ideal method to explore the possibility of building 2D functional nanoelectronic devices. [ABSTRACT FROM AUTHOR]

Li metal has been considered as a potential anode candidate for next‐generation high‐energy Li‐metal batteries, even though the uncontrollable growth of Li dendrites shortens their cycling lifespan. Herein, a reliable and dendrite‐free Li‐metal anode is fabricated via inducing chemical confinement based on an atomic layer deposited lithiophilic ZnO in situ generating LiZn/Li2O arrays. In a configuration, the arrays consisting of uniformly distributed LiZn and Li2O phases, the lithiophilic Li2O phases with favorable Li diffusion barrier guarantee the preferential Li nucleation and prevent the Li diffusion to some sites with uneven charge accumulation. Furthermore, these functional LiZn/Li2O configurations with satisfied localized free electron distribution can effectively decompose the Li clusters to prevent Li aggregation. Meanwhile, the electron‐conductive LiZn phases ensure efficient electron transfer throughout the configuration. Therefore, the LiZn/Li2O‐derived chemical confinement enables uniform Li deposition. Consequently, the as‐prepared Li‐metal anode presents an overpotential <45 mV at 15 mA cm−2 in the symmetrical cells. Moreover, the preferable cycling stability and rate capability are delivered by the as‐assembled cells with a LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode. It is believed that the strategy proposed here can be also beneficial to other effective chemical confinement systems for fabricating high‐performance Li metal anode. [ABSTRACT FROM AUTHOR]

Context. Thermal diffusion is one of the basic processes for the mobility and formation of species on cosmic dust grains. The rate of thermal diffusion is determined by the grain surface temperature, a pre-exponential factor, and an activation energy barrier for diffusion. Due to the lack of laboratory measurements on diffusion, prior astrochemical models usually assume that the diffusion pre-exponential factor is the same as that for desorption. This oversimplification may lead to an uncertainty in the model predictions. Recent laboratory measurements have found that the diffusion pre-exponential factor can differ from that for desorption by several orders of magnitude. However, the newly determined pre-exponential factor has not been tested in astrochemical models so far. Aims. We aim to evaluate the effect of the newly experimentally measured diffusion pre-exponential factor on the chemistry under cold molecular cloud conditions. Methods. We ran a set of parameters with different grain temperatures and diffusion barrier energies using the NAUTILUS astro-chemical code and compared the molecular abundance between the models with the abundance obtained using the experimentally determined pre-exponential factor for diffusion and with the abundance obtained using the values commonly adopted in prior models. Results. We found that statistically, more than half of the total gas-phase and grain surface species are not affected by the new pre-exponential factor after a chemical evolution of 105 yr. The most abundant gas-phase CO and grain surface water ice are not affected by the new pre-exponential factor. For the grain surface species that are affected, compared to the commonly adopted value of the pre-exponential factor for diffusion used in the chemical models, they could be either overproduced or underproduced with the lower diffusion pre-factor used in this work. The former case applies to radicals and the species that serve as reactants, while the latter case applies to complex organic molecules (COMs) on the grain and the species that rarely react with other species. Gas-phase species could also be affected due to the desorption of the grain surface species. The abundance of some gas-phase COMs could be varied by over one order of magnitude depending on the adopted grain surface temperature and/or the ratio of diffusion to desorption energy in the model. Key species whose diffusion pre-exponential factor significantly affects the model predictions were also evaluated, and these species include CH3OH, H2CO, and NO. Conclusions. The results presented in this study show that the pre-exponential factor is one of the basic and important parameters in astrochemical models. It strongly affects the chemistry and should be determined carefully. More experiments to determine the diffusion of grain surface species are helpful for constraining their properties. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) calculations of hydrogen adsorption on titanium nitride had previously shown that hydrogen may adsorb on both titanium and nitrogen sites with a moderate adsorption energy. Further, the diffusion barrier was also found to be low. These findings may qualify TiN, a versatile multifunctional material with electronic conductivity, as an electrode material for the hydrogen evolution reaction (HER). This was the main impetus of this study, which aims to experimentally and theoretically investigate the electrocatalytic properties of TiN layers that were processed on a Ti substrate using reactive ion sputtering. The properties are discussed, focusing on the role of oxygen defects introduced during the sputtering process on the HER. Based on DFT calculations, it is shown that these oxygen defects alter the electronic environment of the Ti atoms, which entails a low hydrogen adsorption energy in the range of −0.1 eV; this leads to HER performances that match those of Pt-NPs in acidic media. When a few nanometer-thick layers of Pd-NPs are sputtered on top of the TiN layer, the performance is drastically reduced. This is interpreted in terms of oxygen defects being scavenged by the Pd-NPs near the surface, which is thought to reduce the hydrogen adsorption sites. [ABSTRACT FROM AUTHOR]

The effects of three additives, CaF 2 , TiO 2 and P 2 O 5 , on the crystallization, microstructure and properties of glass-ceramic glazes in the CaO–Al 2 O 3 –SiO 2 –ZrO 2 system were investigated in detail. The results showed that CaF 2 reduced the viscosity of the glaze and promoted the crystallization of t-ZrO 2 , as well as its conversion to ZrSiO 4. The addition of TiO 2 and P 2 O 5 produced a phase-separated structure that favored t-ZrO 2 crystallization but inhibited its transformation into ZrSiO 4. The stronger the phase separation, the more pronounced this inhibition was. In glass-ceramic glaze containing P 2 O 5 (named PG), t-ZrO 2 was present even at 1250 °C, about 100 °C higher than in conventional zirconium glazes. Further TEM-EDS mapping analysis revealed that Zr was preferentially dissolved in the P-rich droplets. The lack of SiO 2 and the diffusion barrier at the phase-separated interface were the main reasons for suppressing the transition from ZrO 2 to ZrSiO 4. After firing at 1200 °C, PG had a coexistence of ZrO 2 and ZrSiO 4 and exhibited optimal performance, with an L* value of 93.31, a whiteness of 86.5, a gloss of 91.9°, a hardness of 7.06 GPa and a roughness of 30.2 nm. These findings are valuable for the controlled crystallization of Zr-based glass ceramics and related products. [ABSTRACT FROM AUTHOR]

[Display omitted] With the ever-growing demand for high-capacity energy storage technologies, lithium-ion batteries (LIBs) have drawn increasing attention. Ti 2 B 2 , a typical two-dimensional MBenes material, has been considered as a strong contender for anode materials of LIBs with significant performance. However, the limited Li storage capacity of MBenes has hindered its wide applications. To address this issue, we have functionalized Janus-structured MBenes, denoted as Ti 2 B 2 X a X b (X a /X b = N, O, S, Se). Employing first-principles simulations based on density functional theory, we have investigated the geometric characteristics and electrochemical properties of Ti 2 B 2 X a X b. Our results reveal that Ti 2 B 2 NO exhibits an exceptionally large theoretical specific capacity of 1091.17 mAh·g−1, improved by 2.4 times compared with the pristine Ti 2 B 2 (456 mAh·g−1). Li atoms on the O side of Ti 2 B 2 NO possess a low diffusion barrier of 0.33 eV, which is conducive to the rapid charging and discharging of the battery. Moreover, the open-circuit voltage of Ti 2 B 2 NO within the safe voltage range of 0–1 V ensures the safety of battery operation. Overall, our study sheds light on understanding the underlying mechanism of surface functionalization on the Li storage properties of Janus-structured MBenes from atomic-scale, laying the groundwork for future design of high-performance anode materials. [ABSTRACT FROM AUTHOR]

Context: In this study, the electronic structure and diffusion barrier of the Ca-adsorbed WTe2 system under different torsion angles were calculated based on the first-principles method. The results show that the structure and properties of the pure WTe2 system and Ca-adsorbed WTe2 system are affected by torsional deformation. When the torsion angle is 6°, the intrinsic WTe2 changes from a direct band gap to an indirect band gap. The torsional deformation does not change the metallicity of the Ca-adsorbed WTe2 system. The Ca-d state electrons contribute to the electron density of WTe2. The calculation of the diffusion barrier shows that the torsion deformation promotes the diffusion of calcium on the surface of WTe2. This study provides a theoretical basis for the regulation of electrode materials. Methods: In this study, Materials Studio 8.0 software was used to construct the WTe2 model and Ca-adsorbed WTe2 model, and CASTEP module was used for first-principles calculation. [ABSTRACT FROM AUTHOR]

Context: In this study, the electronic structure and diffusion barrier of Ca adsorbed MoTe2 system under different degrees of shear deformation were calculated based on the first-principles method. The results show that both the pure MoTe2 system and Ca-adsorbed MoTe2 system are affected by shear deformation. The pure MoTe2 undergoes a transition from direct to indirect band gap under shear deformation. The adsorption of Ca makes MoTe2 changes from semiconductor to quasi-metal. The results of the density of states show that Ca insertion makes the conduction band part of the adsorption system significantly enhanced. The diffusion barrier of Ca through MoTe2 indicates that the shear deformation promotes the diffusion of Ca on the surface of MoTe2. Shear deformation can effectively modulate the electronic properties of the MoTe2 system, which provides a theoretical basis for the application of MoTe2 materials in the field of ion batteries. Methods: In this study, Materials Studio 8.0 software was used to construct the MoTe2 model and Ca adsorbed MoTe2 model, and the CASTEP module was used for first-principles calculation. [ABSTRACT FROM AUTHOR]

The all-solid-state batteries (ASSBs) are of particular interest because of their higher energy density and improved safety. However, the interfacial instability and resulting high interfacial resistance between the cathode and solid electrolyte (SE) have become the major challenges for the practical application of ASSBs. Herein, we report a stable LiFePO4 cathode/γ-Li3PO4 SE interface and systemically investigate the mechanism of Li-ion transport at the interface and the effects of surface nitrogen doping using first-principles calculations. It is found that delithiation at the LiFePO4/γ-Li3PO4 interface initially occurs at the topmost layer of the LiFePO4 cathode side, and hopping through the interface barrier is a rate-limiting step for Li mobility. Nitrogen doping leads to local structural distortion occurred at the interface, affecting the interfacial Li+ diffusion kinetics. Furthermore, the underlying mechanisms in which the different N doping sites alter the Li diffusion barrier are analyzed. We find that, by a rational design, N doping could significantly enhance Li+ diffusion kinetics. Further analysis of the electronic structure of the interface system reveals that the Li3PO4 electrolyte is electrochemically stable against the LiFePO4 cathode in the N-doped interface. Our findings provide a microscopic understanding of the Li+ transport at solid–solid LiFePO4/γ-Li3PO4 interface and suggest that controlling synthesis condition can be critical for enhancing Li+ transport at the N-doped LiFePO4/γ-Li3PO4 interface in an ASSB. [ABSTRACT FROM AUTHOR]

In an oxidizing environment, the oxide formed on plutonium (Pu) metal is composed of a plutonium dioxide (PuO2) top layer and a thin cubic plutonium sesquioxide (Pu2O3) middle layer. In a reducing environment, the PuO2 layer auto-reduces to cubic Pu2O3. The speed and extent of this conversion depend on the combination of temperature and time. While PuO2 provides a strong diffusion barrier against unwanted Pu corrosion by gaseous species (like hydrogen), Pu2O3 does not, since its crystal structure has chains of oxygen vacancies. The kinetics of the PuO2 reduction are, therefore, of fundamental interest and enable researchers to better protect Pu from corrosion. In this report, the oxygen-diffusion-limited kinetics of the dioxide to sesquioxide conversion were obtained by dynamically heating a PuO2-covered Pu sample from 294 to 418 K in a high-vacuum vessel equipped with an in situ spectroscopic ellipsometer. The physical/chemical constraints in the conversion process were combined with the ellipsometry method of multi-sample analysis to track the percentage of PuO2 and to compute the extent of Pu2O3 formation. The resulting diffusion coefficients were compared against and then combined with complementary literature data to produce a comprehensive set of kinetic parameters for reliably modeling oxide conversion over a larger temperature range than spanned by prior studies. The extracted thermal activation energy barrier (43.7 kJ/mol) and pre-exponential factor (5.0 × 10−10 cm2/s) for the oxygen-diffusion-limited process can be used to accurately model the PuO2 to Pu2O3 transformation in vacuum and/or inert gas applications. [ABSTRACT FROM AUTHOR]

The realization of high interconnect densities for three-dimensional integration demands development of new wafer-to-wafer bonding approaches. Recently introduced Cu-to-Cu wafer-to-wafer hybrid bonding schemes overcome scaling limitations, but like other Cu-based interconnect structures, they are prone to electromigration. Migration and growth of voids, induced by electromigration and mechanical stress, cause Cu-to-Cu hybrid bonds to fail. A comprehensive modeling approach is required to fully understand the complex dynamics of voids with their influencing factors, such as current density, temperature, and mechanical stress. In this work, we utilize such a modeling approach to perform studies of void migration through Cu-to-Cu hybrid bonds. The calculated velocities of the evolving void surface fully correspond to the experimentally observed behavior of voids migrating from the lower pad to the upper diffusion barrier of the upper pad, where they cause electrical failure. The migration velocity of a void in the upper pad is 20% higher than the migration velocity of a void in the bottom pad. Unbalance of the normal velocity distribution at the void surface leads to the transformation of the originally ellipsoid void into a teardrop shape. The simulations provide full insight in the impact of layout geometry, material properties, and operating conditions on void dynamics. In addition, the results enable targeted adjustments of the influencing factors to inhibit void migration and growth in order to delay or to fully prevent Cu-to-Cu hybrid bond failure. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) titanium disulfide (TiS 2) is the lightest transition-metal dichalcogenide (TMD). It exhibits relatively better adsorption and diffusion of sodium (Na) and potassium (K) ions than other TMDs, such as MoS 2 (molybdenum disulfide) and ReS 2 (rhenium disulfide), making it a promising anode material for alkali-ion batteries. Previous studies have found that doping significantly enhances the adsorption and diffusion capabilities of 2D TMDs. For the first time, this work reports the adsorption of Na and K ions on doped TiS 2 monolayers using first-principles calculations, where the Ti atom is substituted by 3d-transition metals, including iron (Fe), cobalt (Co), nickel (Ni), and copper (Cu). Metal-atom doping induces remarkably stronger binding of alkali ions on the surface of TiS 2 , with adsorption energies ranging from − 2.07 to − 2.48 eV for Na and − 2.59 to − 3.00 eV for K. The diffusion barrier energies for alkali ions decrease in the proximity of the doping site and increase as the ions travel away from the doping site for Fe-, Co-, and Ni-doped TiS 2. The average open circuit voltage increases dramatically when Na ions are adsorbed on Fe-doped TiS 2 (by 62%) and Co-doped TiS 2 (by 61%), while K ions result in a moderate improvement of 9% and 8%, respectively. These findings suggest that metal-atom doping considerably improves the electrochemical properties of 2D TiS 2 , potentially enabling its use as anode materials in Na- and K-ion batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] Sodium (Na) metal anodes receive significant attention due to their high theoretical specific energy and cost-effectiveness. However, the high reactivity of Na foil anodes and the irregular surfaces have posed challenges to the operability and reliability of Na metals in battery applications. In the absence of inert environmental protection conditions, constructing a uniform, dense, and sodiophilic Na metal anode surface is crucial for homogenizing Na deposition, but remains less-explored. Herein, we fabricated a Tin (Sn) nanoparticle-assembled film conforming to separator pores, which provided ample space for accommodating volumetric expansion during the Na alloying process. Subsequently, a seamless Na-Sn alloy overlayer was formed and transferred onto the Na foil during Na plating through a separator-assisted technique, thereby overcoming conventional operational limitations of metallic Na. As compared to traditional volumetrically expanded cracked ones, the present autotransferable, highly sodiophilic, ion-conductive, and seamless Na-Sn alloy overlayer serves as uniform nucleation sites, thereby reducing nucleation and diffusion barriers and facilitating the compact deposition of metallic Na. Consequently, the autotransferable alloy layer enables a high average Coulombic efficiency of 99.9 % at 3.0 mA cm−2 and 3.0 mAh cm−2 in the half cells as well as minimal polarization overpotentials in symmetric cells, both during prolonged cycling 1200 h. Furthermore, the assembled Na||Sn-1.0h-PP||Na 3 V 2 (PO 4) 3 @C@CNTs full cell delivers high capacity retention of 97.5 % after 200 cycles at a high cathodic mass loading. [ABSTRACT FROM AUTHOR]

Constructing a hierarchically porous MOF@COF (HP MOF@COF) structure for enhancing the gas-adsorption kinetics. [Display omitted] For ethylene purification, C 2 H 6 -selective metal–organic frameworks (MOFs) show great potential to directly produce polymer-grade C 2 H 4 from C 2 H 6 /C 2 H 4 mixtures. Most C 2 H 6 -traping MOFs are ultra-microporous structures so as to strengthen multiple supramolecular interactions with C 2 H 6. However, the narrowed pore channels of C 2 H 6 -traping MOFs cause large guest diffusion barriers, greatly hampering their practical applications. Herein, we present a feasible strategy by precisely constructing hierarchically porous MOF@COF core–shell structures to address this issue. Additional mesoporous diffusion channels were incorporated between MOF crystals through the construction of the COF shell, thereby enhancing the gas adsorption kinetics. Notably, designing a core–shell MOF@COF structure with an optimal coating amount of mesoporous COF shell will further improve the gas diffusion rate. Breakthrough experiments reveal that the tailored MOF@COF composites can effectively achieve C 2 H 6 /C 2 H 4 separation and maintain its separation performance over five continuous measurement cycles. This investigation opens up a new avenue to solve the diffusion/transfer issues and provides more opportunities and potentials for MOF@COF composites in practical separation applications. [ABSTRACT FROM AUTHOR]

CrN/TiSiN multilayer coatings deposited at 316 L substrate were selected to explore the effects of irradiation on LBE (Liquid Pb–Bi eutectic alloy) corrosion. The as-deposited and irradiated coatings were exposed in LBE. After exposure, all CrN/TiSiN coatings presented oxidation accompanied with PbBi penetration. Irradiated coatings revealed better corrosion resistance with thinner oxide layer and smaller penetration thickness. The largest decrement of 39 % in oxidation thickness was observed in CrN/TiSiN deposited with Ti 80 Si 20 under 150 V. The irradiation-decelerated LBE corrosion could be attributed to the rapidly formed protective oxide layer resulting from the irradiation defects which accelerated nucleation and diffusion process during oxides formation. The decelerated effect was relatively weak in coatings deposited with a bias voltage under 100 V, in which the decrement is under 10 %. The enhanced corrosion resistance was attributed to the quickly formed dense and continuous chromium oxide which rapidly formed due to the irradiation induced defects and acted as diffusion barrier to slow down LBE penetration. [ABSTRACT FROM AUTHOR]

MXenes' tunable properties make them excellent candidates for many applications in future nanoelectronics. In this work, we explore the suitability of Sc 2 CX (X=N 2 , ON, O 2) MXenes to act as the active anode materials in Na-ion based batteries (NIBs) by means of ab initio simulations. After analyzing the structural and elastic properties of all the possible models to evaluate the energetically favorable N and O functionalization sites, our calculations show that both Sc 2 CON and Sc 2 CN 2 present a clear metallic character, making them potential candidates as anode materials. The investigation of the most relevant features for anode performance, such as the adsorption and diffusion of Na atoms, the intrinsic capacity, the open circuit voltage, and the storage capacity, shows that both systems are serious alternatives to the most common 2D materials currently employed in alkali metal batteries. In particular, Sc 2 CN 2 presents better diffusion behavior thanks to the absence of Na clustering on its surface, with optimal diffusion barriers comparable to other 2D materials, such as MoN 2 , while the values of diffusion barriers for Sc 2 CON are at least three times smaller than those found for other anode candidates. Similarly, while the capacity of Sc 2 CON is close to the one reported for 2D Sc 2 C, Sc 2 CN 2 possesses a power density more than twice higher than the ones of 2D materials, such as Sc 2 C, graphite, and MoS 2. Our results, thus, confirm the urge for further experimental exploration of the MXene Sc 2 CX (X=N 2 , ON, O 2) family as anode material in NIBs. [ABSTRACT FROM AUTHOR]

Short-period multilayer mirrors are used in wavelength-dispersive x-ray fluorescence to extend the wavelength range available with naturally occurring Bragg-crystals. W/Si multilayer mirrors with a period of 2.5 nm are used to reflect and disperse elements in the O-Kα–Al-Kα range. However, the reflectance is far from theoretical due to nanoscale W-Si intermixing and formation of WSix. In this work, B4C diffusion barriers were applied in sputter deposited 2.5 nm W/Si multilayers to inhibit W–Si interaction. A peak reflectance of 45% at 9.7° grazing was measured at a wavelength of 0.834 nm—the highest reported in the literature so far. Diffuse scattering measurements revealed no change in interfacial roughness when applying B4C barriers compared to W/Si. A hybrid grazing incidence x-ray reflectivity and x-ray standing wave fluorescence analysis revealed an increase in W concentration of the absorber layer after the application of B4C barriers. Chemical analysis suggests a partial replacement of W silicide bonds with W carbide/boride bonds from the B4C barrier. The formed WxBy and WxCy instead of WxSiy is hypothesized to increase reflectance at 0.834 nm due to its higher W atomic density. [ABSTRACT FROM AUTHOR]

Ion transport in solids is a key topic in solid-state ionics. It is critical but challenging to understand the relationship between material structures and ion transport. Nanochannels in crystals provide ion transport pathways, which are responsible for the fast ion transport in fast lithium (Li)-ion conductors. The controlled synthesis of carbon nanotubes (CNTs) provides a promising approach to artificially regulating nanochannels. Herein, the CNTs with a diameter of 5.5 Å are predicted to exhibit an ultralow Li-ion diffusion barrier of about 10 meV, much lower than those in routine solid electrolyte materials. Such a characteristic is attributed to the similar chemical environment of a Li ion during its diffusion based on atomic and electronic structure analyses. The concerted diffusion of Li ions ensures high ionic conductivities of CNTs. These results not only reveal the immense potential of CNTs for fast Li-ion transport but also provide a new understanding for rationally designing solid materials with high ionic conductivities. [ABSTRACT FROM AUTHOR]

A V2C MXene has a high theoretical capacity and low diffusion barrier, showing tremendous potential in lithium-ion batteries. However, most reports on V2C focus on a multilayered structure that is stacked, which diminishes the ionic accessibility and results in unsatisfactory cycling stability. Therefore, we synthesized a few-layer V2C (f-V2C) material and added multi-walled carbon nanotubes (MWCNTs). The formed f-V2C/MWCNT provides abundant pores, which enhance ionic accessibility, so that Li+ can easily enter the layer space. The introduction of MWCNTs can further separate the f-V2C, expand the specific surface area, reduce the charge transfer resistance, and heighten the structural stability. The experiments reveal that f-V2C/MWCNT has a high specific capacity of 531 mA h g−1 at 0.1 A g−1 after 100 cycles. Even at a high current density of 5.0 A g−1, the specific capacity can still reach 166 mA h g−1. Moreover, the f-V2C/MWCNT structure shows good cycling stability with a capacity retention rate of 95% after 1000 cycles at 5.0 A g−1. The above findings indicate that f-V2C/MWCNT has great application potential in the field of Li+ storage. [ABSTRACT FROM AUTHOR]

The utilization of pristine graphene as an anode material in sodium-ion batteries (SIBs) is limited by its inherent chemical inertness toward Na-ions. To address this issue, we propose a two-dimensional carbon allotrope (named as TD-graphene) by assembling tricyclo[4.4.1.11,6]dodecane (C12H20) skeleton. The topological non-hexagonal feature of C12H20 increases the degree of local carbon-ring disorder and introduces additional electron-deficient regions on the surface, thus enhancing the adsorption capability of Na. TD-graphene demonstrates exceptional stability across the energetic, thermodynamic, dynamic, and mechanical aspects. As a promising anode for SIBs, it exhibits an intrinsic metallicity, an ultra-high storage capacity (1487.58 mA h g−1), a low diffusion barrier (0.20 eV), a low average open-circuit voltage (0.33 V), and a small lattice expansion (0.6%). The presence of solvents with high dielectric constants improves the adsorption and migration capability of Na. Furthermore, taking into account the limitation of single-layer materials in practical applications, we employ h-BN as a promising substrate for TD-graphene, which can boost the Na adsorption and diffusion performance. These results render TD-graphene as a promising high-performance anode material for SIBs. [ABSTRACT FROM AUTHOR]

Thin films of single-phase ruthenium aluminide (RuAl) intermetallic compound were deposited by magnetron co-sputtering. An ordered B2 body-centered cubic structure of high crystallinity was formed after rapid thermal annealing at 800 °C for 1 min. Data fittings using the Fuchs–Sondheimer and Mayadas–Shatzkes models suggested the very short mean free path of electrons of below 5 nm and the high specularity parameter of 0.9. The short mean free path and the much reduced diffuse scattering of electrons at the interface effectively suppressed the resistivity scaling of the B2 RuAl intermetallic compound as compared to ruthenium metal. At an ultra-small film thickness of below 5 nm, the reflection of electrons by grain boundaries or domain walls might alternatively dominate the increase in resistivity. The RuAl intermetallic compound with an ordered B2 structure and a high cohesive energy (a large negative mixing enthalpy) also demonstrated a superior thermal stability at an extreme temperature up to 900 °C. It could be a promising candidate for potential use as the next-generation interconnect metallization without the need of a diffusion barrier. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polyurethane elastomer (TPU) is designed firstly as a solid polymer electrolyte (SPE) for LMBs. • Soft chain forging PEO and hard chain segments IPDI enhance Li+ conductivity, elastic modulus and flexibility of the SPE. • The Li 2 S additive promotes in-situ generatation of LiF at the Li/PEO interface. • Smooth and stable interface enables Li symmetric battery a long cycle of 1400 h at 0.1 mA/cm2. • The Li||LiFePO 4 cell exhibits an excellent capacity retention rate of 80% after 500 cycles at 1C. Li metal anodes have high specific capacity and low electrode potential, and have always been considered as one of the most promising anode materials. However, the growth of Li dendrites, unstable solid electrolyte interface layer (SEI), severe side reactions at the Li/electrolyte interface, and infinite volume expansion of the Li anode seriously hinder the practical application of solid-state Li metal batteries (LMBs). Herein, we report a polyurethane elastomer (TPU) material with high elasticity and interfacial stability as a solid polymer electrolyte (SPE) for LMBs. The synergistic effects of its designed soft chain forging (PEO) and hard chain segments (IPDI) can enhance Li ion conductivity, elastic modulus and flexibility of the SPE to settle the challenges of the Li metal anodes. Moreover, Li 2 S, as a solid-state electrolyte additive, is able to effectively inhibit the occurrence of side reactions at the interface between Li metal and SPE, promote the decomposition of N(CF 3 SO 2) 2 − and in-situ generation of LiF with low Li+ diffusion barrier and excellent electronic insulation, achieving rapid Li ion transport and uniform Li deposition. As a result, stable cycle of up to 1400 h has been achieved for a Li||TPU-Li 2 S||Li battery at 0.1 mA/cm2 at 50 ℃, accompanied with a stable cycling performance of 350 h at a higher current density of 0.5 mA/cm2. Finally, the LiFePO 4 ||TPU-Li 2 S||Li full battery exhibits an excellent cycling performance with a capacity retention rate of 80 % after 500 cycles at 1C. This simple and low-cost strategy provides novel design thoughts for practical application of high-performance SPEs in stable and long-life LMBs. [ABSTRACT FROM AUTHOR]

[Display omitted] Na 4 Fe 3 (PO 4) 2 (P 2 O 7) (NFPP) is currently drawing increased attention as a sodium-ion batteries (SIBs) cathode due to the cost-effective and NASICON-type structure features. Owing to the sluggish electron and Na+ conductivities, however, its real implementation is impeded by the grievous capacity decay and inferior rate capability. Herein, multivalent cation substituted microporous Na 3.9 Fe 2.9 Al 0.1 (PO 4) 2 (P 2 O 7) (NFAPP) with wide operation-temperature is elaborately designed through regulating structure/interface coupled electron/ion transport. Greatly, the derived Na vacancy and charge rearrangement induced by trivalent Al3+ substitution lower the ions diffusion barriers, thereby endowing faster electron transport and Na+ mobility. More importantly, the existing Al—O—P bonds strengthen the local environment and alleviate the volume vibration during (de)sodiation, enabling highly reversible valence variation and structural evolution. As a result, remarkable cyclability (over 10,000 loops), ultrafast rate capability (200 C), and exceptional all-climate stability (−40–60 °C) in half/full cells are demonstrated. Given this, the rational work might provide an actionable strategy to promote the electrochemical property of NFPP, thus unveiling the great application prospect of sodium iron mixed phosphate materials. [ABSTRACT FROM AUTHOR]

Packaging is very important to maintain the quality of food and prevent the growth of microbes. Therefore, the use of food packaging with antimicrobial properties protects the food from the growth of microorganisms. In this study, antibacterial nanocomposite films of polyvinyl alcohol/starch/chitosan (PVA/ST/CS) together with nickel oxide-copper oxide nanoparticles (NiO–CuONPs) are prepared for food packaging. NiO–CuONPs were synthesized by the co-precipitation method, and structural characterization of nanoparticles (NPs) was carried out by XRD, FTIR, and SEM techniques. Composites of PVA/ST/CS, containing different percentages of NPs, were prepared by casting and characterized by FTIR and FESEM. The mechanical properties, diffusion barrier, and thermal stability were determined. The nanoparticles have a round structure with an average size of 6.7 ± 1.2 nm. The cross-section of PVA/ST/CS film is dense, uniform, and without cracks. In the mechanical tests, the addition of NPs up to 1% improved the mechanical properties (TS = 31.94 MPa), while 2% of NPs lowered TS to 14.76 MPa. The fibroblast cells toxicity and the films antibacterial activity were also examined. The films displayed stronger antibacterial effects against Gram-positive bacteria (Staphylococcus aureus) compared to Gram-negative bacteria (Escherichia coli). Furthermore, these films have no toxicity to fibroblast cells and the survival rate of these cells in contact with the films is more than 84%. Therefore, this film is recommended for food packaging due to its excellent mechanical and barrier properties, good antibacterial activity, and non-toxicity. [ABSTRACT FROM AUTHOR]

Aqueous zinc ion batteries (AZIBs) are subject to various unwanted side reactions, including dendrite growth, hydrogen evolution, and corrosion passivation, due to the highly active Zn anode. While constructing an artificial interface layer (AIL) can address these problems, the compromise in Zn deposition kinetics is considerable. Herein, F‐doped modified hydrated calcium silicate (F‐CSH) nanosheets are designed to enhance Zn2+ ion deposition kinetics. Combined with theoretical calculations, it is verified that the F‐doped contributes to higher interface adsorption energy with Zn metal and lower ion diffusion barrier, favoring faster charge transfer compared to non‐F‐doped counterparts. Additionally, the strong interaction between zincophilic F and Zn facilitates rapid desolvation of Zn2+ and promotes the deposition between the Zn metal and F‐CSH interphases. As a result, the F‐CSH layer maintains the stability on the Zn surface, enabling fast and reversible Zn deposition. The F‐CSH@Zn anode exhibits a long lifespan of over 2800 h at 5 mA cm−2, while running more than 2500 cycles at a ≈100% Coulombic efficiency. This work highlights the importance of constructing AIL with strong interaction with Zn2+/Zn in improving the interphase kinetics of zinc anode for realizing the stability of AZIBs. [ABSTRACT FROM AUTHOR]

Wearable metabolite sensors are often limited by easily denaturable enzymes that only allow short‐duration monitoring. Although encapsulating enzymes in metal–organic frameworks (MOFs) shows promise of long‐term enzyme protection, it is typically accompanied by significantly decreased activity due to increased diffusion barrier, steric hindrance for enzyme‐substrate binding, and poor enzyme‐electronic interface. Herein, the co‐encapsulation of enzymes and ultrasmall arginine‐derived carbon dots (Argdot) into a mesoporous Zeolitic Imidazolate Framework‐8 (mZIF‐8) matrix and the enhancement effect of Argdot on enzyme stability and activity, which consequently improves the electrochemical sensor's long‐term sensitivity are investigated. Specifically, the glucose oxidase (GOx)‐Argdot@mZIF‐8 nanocomposite consistently exhibits 40% higher electrochemical sensitivity compared to control GOx@mZIF‐8, an improvement similarly demonstrated with another model enzyme lactate oxidase (LOx). Furthermore, GOx‐Argdot@mZIF‐8 displays excellent stability, retaining 100% of initial sensitivity over 30 days of repeated testing at 37 °C. A touch‐based glucose sensor prototype is demonstrated as an excellent reusable sensor to monitor finger‐tip sweat glucose levels over one month at room temperature. This enzyme encapsulation strategy is not only useful for developing reusable sweat sensors with long‐term monitoring capability, but also promising to expand the industry use of enzymes under harsh conditions. [ABSTRACT FROM AUTHOR]