Energy Density Properties Research Articles

Solubility of letrozole in eight pure and five mixed solvents: Measurement, thermodynamic and molecular simulation analysis

In this work, the solubility of letrozole within eight single and five binary solvents was first systematically investigated at 283.15 K to 323.15 K via the gravimetric method. Subsequently, four thermodynamics formulas including modified Apelblat, λh, GSM and Jouyban-Acree were utilized to link the experimental outcomes of letrozole, all models achieved the good fitting performance and the ARD% was less than 2 %. The dissolvability of letrozole in chosen solvents exhibited a positive correlation with temperature, and co-solvency was observed in such mixed solvent systems as ethyl acetate + 1-propanol, and acetonitrile + 1-propanol. Furthermore, the sites of hydrogen bonding donor and acceptor of letrozole and solvents were analyzed through the molecular electrostatic potential surfaces (MEPs). Then solvent effect, solvation free energy and radial distribution function (RDF) analysis gained via molecular simulation were utilized to illuminate experimental phenomena, the outcomes manifested the polarity, cohesive energy density and other properties of solvents along with both solvent–solvent and solute–solvent interactions contributed differently to the dissolution processes. In the end, the apparent thermodynamic identities concerning letrozole within chosen solvent systems were computed under the van’t Hoff and Gibbs formulas, and outcomes showed that dissolution concerning letrozole was a procedure of endothermic and entropy mainly driven.

Optimizing O3-type cathode materials with modified collector for sodium-ion batteries: Insights of interfacial reaction between collector and electrolyte

In order to obtain a sodium-ion battery with high energy density and good kinetic properties, high specific capacity of O3-type NaNi1/3Fe1/3Mn1/3O2 (NFM111) cathode material and high ion migration rate of NaClO4 electrolyte are selected. The cycling performance of NaNi1/3Fe1/3Mn1/3O2 is tested at 0.5 C after pre-activation at 0.1 C. During the electrochemical testing, a kind of side reaction products are found on the surface of the electrode piece. Through Scanning emission microscopy (SEM), X-ray photoelectron spectroscopy analysis (XPS) and Raman tests, side reaction products are found on the current collector with NaClO4 and Fluoroethylene carbonate (FEC). The protective layers are constructed on the surface of Al foil to effectively avoid the occurrence of side reactions. The prepared half cells have excellent stability and rate performance by the modified current collector. After 100 cycles at 0.5 C, the specific discharge capacity is 106 mA h g−1. The specific discharge capacity at 5 C is 107.2 mA h g−1. This measure provides a new idea to the NFM111 cathode materials electrochemical test and offers research basis for the design of sodium ion battery with excellent dynamic performance. Meanwhile, it also eliminates industry doubts about the performance of sodium-ion batteries.

Enhanced Dielectric, Thermal, Energy Storage, Quality Factor, Impedance, and Conductivity Properties of Novel PVDF/PAN/ZrO2 Polymer Nanocomposites for Flexible Electronics Applications

ABSTRACTIn this study, novel polymer nanocomposite films based on polyvinylidene fluoride/polyacrylonitrile/zirconium dioxide (PVDF/PAN/ZrO2) were prepared using a solution casting technique. The structural modifications and morphological properties were analyzed by x‐ray diffraction (XRD) and high resolution scanning electron microscopy (HRSEM). The obtained results verified the filler‐polymer interactions and uniform dispersion of the ZrO2 filler in the host polymers (PVDF and PAN). Thermal stability of up to 46% leftover residue for 30% ZrO2 nano‐filler loading in the blend polymer nanocomposite was analyzed by thermogravimetric analysis (TGA). The dielectric properties such as dielectric constant and dielectric loss values and impedance, Q‐factor, and AC conductivity were analyzed using an impedance analyzer. The decrement in impedance with increasing nano‐filler content with improved dielectric, thermal, Q‐factor, energy density and conductivity properties signifies the prepared novel PVDF/PAN/ZrO2 polymer nanocomposite as an effective material for flexible electronics applications.

Flexible PVDF-Ba0.97Ca0.03TiO3 polymer-ceramic composite films for energy storage, biosensor, mechanosensor, and UV–visible light protection

Multifunctional piezoelectric devices, which can detect pressure, store electrostatic energy, block UV radiation, and generate electricity from body movements, are highly beneficial for enhancing individual well-being. To achieve these capabilities, polyvinylidene fluoride (PVDF) composite films with Ba0.97Ca0.03TiO3 (BCT3) filler were prepared, varying the BCT3 content from 0 to 50 wt.%. The BCT3 ceramic, prepared using a modified solid-state reaction, exhibits a tetragonal phase at room temperature with a d33 value of 105 pC/N. X-ray diffraction confirms composite formation. The beta phase ranges from 75 to 86.9 %. At 40 wt.% BCT3, the dielectric constant, energy density, and piezoelectric properties peak, yielding maximum Wrec and Wtot of 138.1 and 284.7 mJ/cm3 (@ 250 kV/cm), respectively. PVDF-BCT3-40 (40 wt.%) shows maximum voltage, current, and power density of 25 V, 26.8 nA, and 19.8 μW/cm3 under a 50 N load. Increasing BCT3 content enhances UV–visible absorbance, making the composites effective for light shielding.

Surface engineered covalent bridging strategy to in-situ fabricate MXene-based core-sheath fiber for flexible supercapacitors with ultrahigh volumetric energy density and mechanical properties

MXene fiber-based supercapacitors (SCs) are expected to make a major contribution to the ongoing development of wearable electronics and metaverse technologies in future. However, to fabricate fiber electrodes with high energy density and strong mechanical properties remains a major challenge for their usage in SCs. Herein, we fabricated a flexible core-sheath structural Ti3C2Tx MXene@polyaniline (MX@PA) fiber electrode with ultrahigh volumetric energy density and good tensile strength through surface engineered covalent bridging strategy via wet spinning and in situ oxidant-freepolymerization processes. Benefiting from the high-order core-sheath structure and strong Ti-O-N covalent bonds between MXene and PANI, an ultrahigh tensile strength (∼168.1 MPa) and super-toughed (∼1.75 MJ cm−3) fiber electrode was achieved. The assembled SC provided much higher volumetric capacitance of 631F cm−3 (based on the SC device) at a current density of 0.5 A cm−3 and ultralong-term cycling stability with 92.6 % capacitance retention after 10000 cycles due to the rapid electron conduction of core (MXene) and large pseudocapacitive charge transfer of the sheath (PANI). As a result, the SC delivers excellent volumetric energy density of 56.1 mWh cm−3 at a power density of 204.9 mW cm−3. The integrated SC found actual application to power a 2.5 V red LED.

A Comprehensive Comparison of the Structural, Ferroelectric, Energy Storage, and Photocatalytic Properties of Chemical Composition-Tailored Perovskite Ceramics

This article reports on the structural, ferroelectric, energy density, and photocatalytic properties of (Pb0.50Ba0.35Ca0.15)(Fe0.25Nb0.25Ti0.50)O3 [PBCTO] and (Pb0.50Ba0.50)(Fe0.25Nb0.25Zr0.1Ti0.40)O3 [PBZTO] ceramics synthesized by the solid synthesis route. X-ray diffraction and Raman spectra confirmed peaks corresponding to perovskite crystalline structure with tetragonal phase for both PBCTO and PBZTO ceramics. Slim ferroelectric hysteresis was observed in polarization-electric field measurements. Remnant polarization (Pr), and coercive field (Ec) values are ∼3.63 μC cm−2, ∼25.4 kV cm−1, and ∼1.39 μC cm−2 and 17.9 kV cm−1 for PBCTO and PBZTO, respectively. Energy densities were obtained from ferroelectric hysteresis loops. For PBCTO ceramics, the largest unreleased energy density is 0.72 J cm−3 @ 200 kV cm−1; for PBZTO ceramics, the largest unreleased energy density is 0.60 J cm−3 @200 kV cm−1. Photocatalytic performance was studied on methylene blue (MB) and methyl orange (MO) dyes under visible irradiation. The degradation percentage of MB dye in the presence of PBCTO and PBZTO was found to be 56% and 98% in 80 min with irradiation. The degradation percentage of MO dye in the presence of PBCTO and PBZTO at their respective wavelength was 48% and 97% in 120 min with irradiation. These bulk ceramics under study have shown interesting multifunctional properties useful for various potential applications.

(Battery Division Postdoctoral Associate Research Award Sponsored by MTI Corporation and the Jiang Family Foundation) Science of Multiphysics Behavior of Si/C Composite Anodes in High-Energy-Density Lithium-Ion Batteries

The rapidly growing demands on energy storage technologies over the last decade have imposed further requirements for the high energy/power density, safety, and durability of lithium-ion batteries (LIBs). Si/C composite materials have attracted enormous research interest as the most promising candidates for the anodes of next-generation lithium-ion batteries, owing to their high energy density and mechanical buffering property. However, the major disadvantage of materials with ultra-high capacities, such as Si-based materials, is the significant volume change during cycling, which further leads to mechanical and electrochemical degradation. However, a sophisticated and quantitative understanding of the highly electrochemical-mechanical coupling behaviors is still lacking.A comprehensive computational model is indispensable in the developing process of the excellent performance of anode material due to the low-realizability, inconvenience, and high-cost of experiments, which also provides powerful tools for fabrication guidance of novel Si/C composites designs. Hence, a multiphysics modeling framework is established with a detailed geometric description to quantitatively reveal the underlying governing mechanisms of Si/C composite anode behaviors. We studied the effects of the Si weight percentage, the Si-related particle distribution, the Si-related particle size, the mechanical constraint, and the binder domain gradient on the battery performance regarding the potential behavior, capacity delivery, mechanical stress/strain, Li plating, and polarization evolution. In our study, we used silicon monoxide (SiO) as the Si element source and graphite (Gr) as the C element source. Results discover that an 8-10 wt% of SiO would be an optimal choice regarding capacity delivery and minimizing Li plating under 1C constant current charging condition. Positioning SiO particles near the separator and reducing the sizes of SiO particles are also demonstrated to be beneficial for electrochemical performance with trivial influence on mechanical mismatch. In addition, the mechanical constraint demonstrates a balanced effect on the overall performance of cells and the local behaviors of particles. Our findings also indicate that reducing the proportion of carbon-binder domain (CBD) in the upper domain (near the anode surface) compared to the lower domain (near the current collector) positively influences electrochemical performance, particularly in terms of capacity and Li plating. However, such an arrangement introduces potential risks of mechanical failures and we recommend to incorporate a higher proportion of CBD alongside the SiO particles. Finally, an anode design with a lower CBD proportion in the upper domain exhibits superior rate performance.This study explores the multiphysics behavior of Si/C anodes material using a comprehensive methodology combining experimental and FEA techniques, systematically revealing the coupling mechanism among various physical fields, as well as providing efficient and powerful tools in the design, development, and evaluation of high energy density lithium-ion batteries.

Systematical High-Pressure Study of Praseodymium Nitrides in N-Rich Region

Abstract We investigate high-pressure phase diagrams of Pr–N compounds by proposing five stable structures (Pnma-PrN, I4/mmm-PrN2, C2/m-PrN3, P 1 ¯ -PrN4, and R3-PrN8) and two metastable structures ( P 1 ¯ -PrN6 and P 1 ¯ -PrN10). The P 1 ¯ -PrN6 with the N14-ring layer and R3-PrN8 with the N18-ring layer can be quenched to ambient conditions. For the P 1 ¯ -PrN10, the N22-ring layer structure transfers into infinite chains with the pressure quenched to ambient pressure. Remarkably, a novel polynitrogen hR8-N designed by the excision of Pr atoms from R3-PrN8 is obtained and can be quenched to ambient conditions. The N-rich structures of P 1 ¯ -PrN6, R3-PrN8, c-PrN10 and the solid pure nitrogen structure exhibit outstanding properties of energy density and explosive performance.

Halloysite nanotubes enhanced polyimide/oxidized-lignin nanofiber separators for long-cycling lithium metal batteries

The high energy density and robust cycle properties of lithium-ion batteries contribute to their extensive range of applications. Polyolefin separators are often used for the purpose of storing electrolytes, hence ensuring the efficient internal ion transport. Nevertheless, the electrochemical performance of lithium-ion batteries is constrained by its limited interaction with electrolytes and poor capacity for cation transport. This work presents the preparation of a new bio-based nanofiber separator by combining oxidized lignin (OL) and halloysite nanotubes (HNTs) with polyimide (PI) using an electrospinning technique. Analysis was conducted to examine and compare the structure, morphology, thermal characteristics, and EIS of the separator with those of commercially available polypropylene separator (PP). The results indicate that the PI@OL and PI-OL@ 10 % HNTs separators exhibit higher lithium ion transference number and ionic conductivity. Moreover, the use of HNTs successfully impeded the proliferation of lithium dendrites, hence exerting a beneficial impact on both the cycle performance and multiplier performance of the battery. Consequently, after undergoing 300 iterations, the battery capacity of LiFePO4|PI-OL@ 10 % HNTs|Li stays at 92.1 %, surpassing that of PP (86.8 %) and PI@OL (89.6 %). These findings indicate that this new bio-based battery separator (PI-OL@HNTs) has the great potential to serve as a substitute for the commonly used PP separator in lithium metal batteries.

A Review of Macrocycles Applied in Electrochemical Energy Storge and Conversion.

Macrocycles composed of diverse aromatic or nonaromatic structures, such as cyclodextrins (CDs), calixarenes (CAs), cucurbiturils (CBs), and pillararenes (PAs), have garnered significant attention due to their inherent advantages of possessing cavity structures, unique functional groups, and facile modification. Due to these distinctive features enabling them to facilitate ion insertion and extraction, form crosslinked porous structures, offer multiple redox-active sites, and engage in host-guest interactions, macrocycles have made huge contributions to electrochemical energy storage and conversion (EES/EEC). Here, we have summarized the recent advancements and challenges in the utilization of CDs, CAs, CBs, and PAs as well as other novel macrocycles applied in EES/EEC devices. The molecular structure, properties, and modification strategies are discussed along with the corresponding energy density, specific capacity, and cycling life properties in detail. Finally, crucial limitations and future research directions pertaining to these macrocycles in electrochemical energy storage and conversion are addressed. It is hoped that this review is able to inspire interest and enthusiasm in researchers to investigate macrocycles and promote their applications in EES/EEC.

Layer effects on MXenes electrode and it applied to silicon composite structures

Despite the very high capacity of Si (4200mAh g−1), the widespread application of Si anodes has been hampered by drastic volume changes (up to 300 %) during cycling, leading to electrical contact losses and thus a sharp drop in capacity as the cycle life is shortened. Here we present a class of layered MXene/Si electrodes, which consist of nano-Si embedded in the interlayers of MXene to form a coupling effect, which can inhibit the huge volume change of Si during cycling. Therefore, layered MXene/Si has a highly reversible capacity, much improved cycling performance and excellent mechanical properties. First-principles calculations reveal the excellent electronic conductivity and good diffusion ability of layered MXene/Si, confirming the rapid storage of Li ions. This study provides useful information for the development and production of anode materials with high energy density and good mechanical properties.

The intermediate valence state Mo5+ in Fe doping La2(MoO4)3 boosting electrochemical nitrogen reduction

NH3 is considered as an ideal fuel for fuel cells to achieve zero carbon emissions due to its high energy density (at liquefaction) and carbon-free properties. The zero-carbon clean electrocatalytic nitrogen reduction reaction (NRR) is one of the alternative routes for NH3 synthesis. The efficiency of NRR is restricted by the high stability of N N and the slow reaction rate. In this study, La2(MoO4)3 (LaMo), and x%Fe doping-LaMo (x = 3, 5, 7, and 10) are synthesized via a hydrothermal method. The strong electron-donating ability of Fe converts a part of Mo6+ to Mo5+ and Mo4+ improving the electronic environment. The presence of Mo5+, an intermediate valence state, facilitates the oxidation and reduction reactions and establishes rapid electron transport channels. The electron transport of Mo6+↔e−Mo5+ is easier than Mo6+↔2e−Mo4+. Furthermore, the Mo5+ activates N2 and enhances N2 adsorption, boosting the NRR performance. Importantly, the content of Mo5+ exhibits a positive correlation with NH3 yield rate (R2 = 0.89), and Faradaic efficiency (FE, R2 = 0.95). Consequently, the 5%Fe–LaMo exhibits the highest Mo5+ percentage (75.9 %) and NRR performance (NH3 yield rate:30.4 μg h−1 mgcat−1, FE: 3.6 %). Thus, this study proposes a method to enhance the NRR performance by element doping with strong electron-donating ability to regulate the Mo5+ percentage.

Effect of reaction temperature and concentration of H2SO4 acid in the unzipping process of carbon nanotubes to form graphene nanoribbons

Unzipping carbon nanotubes (CNTs) is one of the methods to produce graphene nanoribbons. In this research, we investigated the effect of reaction temperature and concentration of H2SO4 acid on graphene nanoribbons (GNRs) formation. By increasing the reaction temperature, the transformation of CNTs to form GNRs is getting better. The results showed that the unzipping process was strongly affected by temperature. At 100 °C temperature, GNRs obtained 100% yield with a purity of +99%C and surface area of 250 m2/g. Furthermore, H2SO4 acid is the only environment for the wet chemical reaction, it doesn’t affect GNRs quality so the low concentration of acid will be utilized and contribute to reducing the environmental impact in the world. The GNRs will be a potential material for both anode and cathode in batteries and supercapacitors to get higher energy density and fast charging properties.

Three-dimensional faveolate porous N-doped carbon skeleton embodied with nano Bi toward stable less-Na sodium metal batteries

Sodium metal batteries (SMBs) have been widely investigated recently due to the low price of Na metal, satisfactory energy density and similar chemical properties to lithium. However, SMBs also face challenges like low Na utilization, dendrite growth, dead sodium accumulation, unstable solid electrolyte interphase and massive bubble generation. To improve their safety and cycling stability, herein, we fabricate a porous hybrid framework, i.e., fine Bi nanoparticles anchored in porous N-doped carbon matrix (Bi@PNC), as a modified layer upon Cu collector toward stable SMBs. Upon electrochemical activation, the nanoscale Bi-derived Na–Bi alloy with high sodiophilicity reduces the nucleation overpotential of Na, inhibits the formation of Na dendrites, and decreases the loss of Na during cycling. Thanks to these striking merits, the half cells assembled with Na undergo 1600 cycles (3200 h) at 1 mA cm−2, 1 mAh cm−2 with the average Coulombic efficiency of 99.95%. The optimized Bi@PNC based symmetric cells still maintain the overpotential of ∼9.2 mV under 1 mA cm−2 and depth of discharge of 16.7% after cycling for 2420 h. Furthermore, the assembled less-Na full SMBs exhibit superb electrochemical properties. Our strategy here provides meaningful avenue to construct stable less-Na metallic anodes for advanced SMBs.

Self-Limited Formation of Cobalt Nanoparticles for Spontaneous Hydrogen Production through Hydrazine Electrooxidation.

Hydrogen (H2) has emerged as a highly promising energy carrier owing to its remarkable energy density and carbon emission-free properties. However, the widespread application of H2 fuel has been limited by the difficulty of storage. In this work, spontaneous electrochemical hydrogen production is demonstrated using hydrazine (N2H4) as a liquid hydrogen storage medium and enabled by a highly active Co catalyst for hydrazine electrooxidation reaction (HzOR). The HzOR electrocatalyst is developed by a self-limited growth of Co nanoparticles from a Co-based zeolitic imidazolate framework (ZIF), exhibiting abundant defective surface atoms as active sites for HzOR. Notably, these self-limited Co nanoparticles exhibit remarkable HzOR activity with a negative working potential of -0.1V (at 10mA cm-2) in 0.1m N2H4/1m KOH electrolyte. Density functional theory (DFT) calculations are employed to validate the superior performance of low-coordinated Co active sites in facilitating HzOR. By taking advantage of the potential difference between HzOR and the hydrogen evolution reaction (HER), a novel HzOR||HER electrochemical system is developed to spontaneously produce H2 without external energy input. Overall, the work offers valuable guidance for developing active HzOR catalyst. The novel HzOR||HER electrochemical system represents a promising and innovative solution for energy-efficient hydrogen production.

Bio-inspired design of PTFE/B energetic materials with high reactivity and flexibility

Although new-type energetic materials have been investigated extensively, there is a challenge on how to integrate energy density and mechanical properties of energetic materials simultaneously. Herein, a versatile approach was proposed to design energetic materials with high energy density, reactivity, and flexibility based on a bio-inspired strategy. By mimicking the “brick-and-mortar” structure within a natural nacre, the energetic film with alternative layers of polytetrafluoroethylene (PTFE) and boron (B) was successfully fabricated. The nacre-mimetic PTFE/B energetic film exhibited excellent reaction heat (4413.9 J⋅g−1) and bright combustion flame, which may originate from the exothermic reaction mechanism between fluorine (F) and B. Even more remarkably, such PTFE/B energetic film revealed prominent mechanical flexibility reported for the first time. These findings indicate that the nacre-mimetic strategy provides an effective route to engineer energetic materials with high energy density, reactivity, and flexibility.

Unlocking Charge Transfer Limitation in NASICON Structured Na3V2(PO4)3 Cathode via Trace Carbon Incorporation

AbstractNASICON‐type cathode with remarkable ionic conductivity is perspective candidate for fast‐charging sodium‐ion battery. However, severely restricted by low electrical conductivity and poor interfacial kinetics, it usually delivers poor charge transfer kinetics. Different from traditional carbon compositing with high carbon contents, herein, a trace carbon incorporation tactic is proposed based on a typical NASICON‐structured Na3V2(PO4)3. First, particle‐growth process of Na3V2(PO4)3 is regulated via incorporating carbon dot, significantly reducing its particle size to shorten charge diffusion path. Second, electrical conductivity of Na3V2(PO4)3 is improved without sacrificing its high electrochemical activity due to the incorporated trace carbon content (0.76 wt.%). Third, Na3V2(PO4)3‐electrolyte interface structure is optimized by abundant functional groups from the incorporated carbon dot, enabling a thin and stable NaF‐rich CEI layer to boost interface kinetics. As a result, carbon dot endows Na3V2(PO4)3 with ultrastable cyclability up to 20 k cycles (capacity retention of 98.4%) and excellent rate capability (up to 200 C) in half cell, as well as high energy density (368.7 Wh kg−1) and fast charging property (≈110.2 s per charging with 250.8 Wh kg−1 input) in full cell. This study carves a new path for developing fast‐charging cathode, as is increasingly desired for present energy storage applications.

Conductive Robust Interfaces with Fluoro-Borate Based Electrolyte Additive for 4.6V Well-Cycled LiNi0.90Co0.06Mn0.04O2||Li Batteries.

Owing to the outstanding comprehensive properties of high energy density, excellent cycling ability, and reasonable cost, Ni-rich layered oxides (NCM) are the most promising cathode for lithium-ion batteries (LIBs). To further enhance the specific capacity of Ni-rich layered oxides, it is necessary to increase the cut-off voltage to a higher level. However, a higher cut-off voltage can lead to substantial structural changes and trigger interface side reactions, presenting significant challenges for practical applications (cycle life and safety). Herein, to solve above issues, tris(hexafluoroisopropyl)borate (TFPB) is introduced as a high voltage electrolyte additive for LiNi0.90Co0.06Mn0.04O2 cathode. Based on detail in situ/ex situ characterization, this study proves that TFPB forms a protective solid-state interphase (SEI) layer on the Li-anode. Additionally, derivatives of TFPB are easily oxidatively decomposed to create a dense cathode electrolyte interphase (CEI) film on the cathode. This CEI film effectively prevents the continuous oxidation of the electrolyte and mitigates the adverse effects of HF on the battery. Benefit from the protective SEI and CEI layer, the LiNi0.90Co0.06Mn0.04O2||Li battery with a TFPB-containing electrolyte maintains an unprecedented level of performance, with a capacity retention of 89.1% after 100 cycles under the ultrahigh cut-off voltage of 4.6V (vs Li/Li+).

Tailoring the non-coherent interfacial precipitation to overcome the trade-off between strength-ductility and impact energy release in Ti–Zr–Hf–Nb–Ta high entropy alloy

The energetic high-entropy alloys have brought a new idea for the development of new energetic structural materials (ESMs) with high energy density and excellent mechanical properties. However, the energetic high-entropy alloys exhibit a significant trade-off between strength-ductility and impact energy release efficiency. Here, we develop a new strategy to introduce non-coherent interfacial nanoprecipitates into the Ti–Zr-Hf-Nb-Ta BCC energetic high-entropy alloy, which can not only exert the precipitation strengthening mechanism to maintain excellent mechanical properties, but also transform the local shear fracture into multiple cracks along the grain boundary to promote energy release. The nanoprecipitation-strengthened energetic high-entropy alloy achieved a four-times greater fireball area generated by impact energy release than that of the single-phase BCC alloy, while maintaining an excellent mechanical property combination of high dynamic compression strength (1787 MPa) and high fracture strain (40 %). The results provide new insights into the development of energetic high-entropy alloys with superior impact energy release and strength-ductility synergy.

High-performance palladium nanotube network as fast, high-resolution, and wide range hydrogen detector in atmosphere

Due to its high energy density, cleanliness, and renewable properties, hydrogen (H2) has found wide applications in aerospace, fuel cells, biomedicine, and chemical production. However, ensuring its safety is crucial, and a quick response time for H2 leakage detection is urgently needed for subsequent explosion-proof measures, requiring a limit of less than 5 s. So far, there is no reported device with both high-resolution and wide range capabilities. In this study, we propose a novel solution by designing and fabricating a hollow palladium nanotube network (HPNN) as a rapid leaking-sensing H2 detector. The HPNN sensor demonstrates excellent performance with a low detection limit of 10 parts per million (ppm) and a fast response time of less than 0.6 s in atmospheric environment. These impressive safety characteristics are attributed to the unique structure of the Pd nanotube network, where both the lattice volume expansion effect and electron accumulation under mechanical deformation affect the electrical resistance. The device is capable of effectively detecting a wide range from 4 % to 0.001 % of H2 concentrations. Compared to previous results, the response speed is improved by over 8 times at the minimum explosion concentration (4 %) and two orders of magnitude at low limit concentration. Such simple and cost-effective manufacturing method offers potential for the development of high-performance hydrogen leakage detectors.