Efficient Materials Research Articles

Designing a series of RE based carbon composites (RE=Tb, Gd, Ho, Lu, Nd, Sm, Yb, Eu, and Ce)-especially Tb-N-Cs for oxygen reduction enhancement

Iron and nitrogen co-doped carbon materials (Fe–N–Cs) have enormous application prospects in cathodic oxygen reduction reaction (ORR) as efficient electrode materials. However, their stability is of great importance, but is still limited by severe Fenton reaction due to the preferential reaction between Fe2+ and H2O2. This paper intends to rationally design a series of rare earth (RE) metals based carbon matrix anchoring RE centers directly converted from RE oxides and small nitrogen-containing carbon molecules by employing the molten-salts-assisted pyrolysis. A class of prepared RE based carbon (RE-N-Cs) catalysts surprisingly exhibits ORR activities comparable to that of Pt/C. The Tb–N–Cs sample with the best catalytic activity among them was characterized by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC-HAADF-STEM) and X-Ray Diffraction (XRD). The characterization results show the presence of Tb single-sites in carbon substrate, with Eonset of 1.06 V and Jd of 6.37 mA cm−2, exceeding those of the commercial Pt/C (Eonset = 0.96 V vs. RHE; Jd = 5.64 mA cm−2).

Recyclable polyethylenimine based polymer for selective Pd(II) recovery and Suzuki reaction: Waste to treasure tactics

Developing efficient materials for the selective capture of Pd(II) from secondary sources, along with the reutilization of spent Pd(II)-loaded adsorbents, is of great significance, but remains great challenging. Herein, a highly efficient adsorbent (TP@PEI) was fabricated through polycondensation of polyethyleneimine (PEI) with 1,3,5-triformylphoroglucinol (TP), which selectively extracts palladium ions from simulated industrial wastewater, with preferential uptake of Pd(II) over 9 competing cations. The TP@PEI achieves ultrafast capture of Pd(II) in just 20 min, with an impressive adsorption capacity of 620 mg g−1. Of greater significance, the removal efficiency for Pd(II) reaches 99.9 % at a concentration of 100 mg L-1, which still remains at a remarkable 99 % after 11 adsorption–desorption cycles. Exceptional 99.9 % Pd(II) recovery is achieved through the adsorption of a depleted Pd-digested solution, while the breakthrough test validates its practicality and impressive bed breakthrough time (1070 min). Mechanism study reveals that the exceptional adsorption performance of TP@PEI for palladium is driven by synergistic interactions, including coordination and electrostatic interactions. Furthermore, the waste Pd(II) loaded TP@PEI efficiently catalyzes the Suzuki reaction in water, achieving a remarkable 99 % yield of the targeted compound. This research showcases a strategy for converting industrial waste into a valuable resource by meticulously engineering materials to extract precious metals from wastewater, subsequently repurposing them as high-performing catalysts.

Molecularly and Structurally Designed Polyimide Nanofiber Radiative Cooling Films for Spacecraft Thermal Management

AbstractRadiative cooling films (RCFs) are crucial for spacecraft thermal management, but their optical performance is currently limited by their structures and intrinsic high absorption at short wavelengths. In this study, a novel RCF using electrospun polyimide nanofibers optimized at both the molecular and microscale levels is developed. The newly designed polyimide molecules significantly decrease visible and ultraviolet (UV) light absorption while maintaining excellent thermal radiation properties in the infrared spectrum. By optimizing the diameter and orientation of the nanofibers using Monte Carlo simulations, the resulting film achieves a solar reflectivity of 99.6% and a mid‐infrared emissivity of 0.93. Its physical structures and optical properties remain stable under exposure to UV light, atomic oxygen, and extreme temperature changes. Further vacuum radiative cooling tests reveal that the thermal equilibrium temperature of this film is approximately 28 °C lower than that of Kapton‐based RCFs currently used in spacecraft. These results provide a new approach for creating efficient thermal management materials for space applications, with potential for broader use in architecture, electronic devices, and outdoor equipment.

In-situ synthesis of bifunctional N-doped CoFe₂O₄/rGO composites for enhanced electrocatalysis in hydrogen and oxygen evolution reactions

The development of cost-effective and efficient materials for electrochemical water splitting using non-noble metal oxide is a promising strategy to promote clean energy and mitigate environmental issues. In this study, we synthesized N-doped CoFe2O4 (NCF) and various wt% rGO-loaded N-doped CoFe2O4 (x = 1 %, 3 %, and 5 %; denoted as NCFRx) using a hydrothermal method. Subsequently, the NCF and NCFR3 samples were annealed at four different temperatures (y = 550, 600, 650, and 700 °C; denoted as NCFR3-y). FE-SEM, TEM, and XPS studies revealed a strong interface between rGO nanosheets and N-doped CF, acting as electron transport carriers that enhance performance in hydrogen and oxygen evolution reactions (HER and OER). The electrochemical evaluation of the prepared materials was carried out in a 1.0 M KOH electrolyte. The nickel foam (NF) electrode supported by the NCFR3–650 composite demonstrated excellent and stable electrocatalytic performance with a minimum overpotential of 73 mV and 170 mV at a current density of 10 mA/cm2 for HER and OER, respectively, and achieved excellent faradaic efficiencies of 91.01 % for OER and 90.48 % for HER. These results confirmed that the NCFR3–650@NF composite catalyst was comparable to standard Pt/C and IrO2, exhibiting lower overpotential and Tafel slope at a current density of 10 mA/cm2. The double layer capacitance (Cdl) of NCFR3–650@NF (7.70 mF/cm2) was higher than that of other electrocatalysts, indicating a large electrochemically active surface area. The structural properties of NCFR3–650@NF contributed to improved stability during long-term HER and OER analysis. Therefore, the developed NCFR3–650@NF electrocatalyst is a promising alternative to noble metal-centered systems for water splitting, offering overall high efficiency.

Performance analysis of wire-electrochemical discharge cutting of glass material

The present study investigated the feasibility of micro-cutting in glass material by using Electrochemical Discharge Machining (ECDM) Process. Glass possesses outstanding properties that make it a versatile with widely used in a diverse range of applications. Because of its tendency to fracture brittle during machining, glass is typically processed in its liquid or viscous state to manufacture precise and high-quality parts. Machining glass with good dimensional accuracy is a challenging task due to its fragile nature. Therefore, researchers have recognized the very appropriate technique for machining glasses with precision. The Wire-Electrochemical Discharge Machining (WECDM) has been identified as the most economical and efficient technique for fabricating micro slits in thin glass samples. In the present work, an in-house setup for WECDM was developed and the feasibility of the developed configuration was examined. Two different thicknesses of glass specimen have been considered for experimentation for checking the quality of cut and it is found that thinner specimen possesses good quality cut. The regression model has been developed to find a relationship between input and response parameters. The developed regression model was reasonably well fitted with the observed values where applied voltage 55V, 15% by wt. electrolyte concentration and 70% duty cycle were the most influencing parametric combinations among others. Further mixed electrolytes have shown excellent performance up to a certain concentration in terms of Material Removal Rate (MRR). This study reveals that optimal capillary action, influenced by surface tension and electrolyte concentration, is crucial for consistent sparking and efficient material removal in WECDM.

CNTs/lamellar VSe2/Fe3O4 self-assembled a variety of unique three-dimensional multilayer interface structures and microwave absorption properties

Fabrication of microwave absorption (MA) materials of matched small thickness, low density, broad effective absorption bandwidth (EAB), as well as high absorption performance remains a technical challenge to be solved today. In this paper, three-dimensional (3D) VSe2/CNTs/Fe3O4 ternary composites with a variety of self-assembled structures were fabricated by a two-step hydrothermal and one-step carbothermal reduction method. Via varying the content of Fe3O4 in the composites, different 3D multilayer interfacial structures, such as star fruit-, bitter melon-, goldfish-, starfish-, peony- and chrysanthemum-shaped structures were self-assembled, and excellent MA absorption characteristics were obtained. The best reflection loss (RLmin) was −50.96 dB at 1.8 mm thickness. The maximum EAB was 4.93 GHz at 2.0 mm thickness. Carbon nanotubes mainly contributed to conduction and polarization losses. In situ generated VSe2 nanosheets and Fe3O4 nanoparticles promoted the assembly of multilevel interfacial structures, thus contributing to interfacial polarization loss and dipole polarization loss. Fe3O4 also created magnetic losses. This study lays the foundation for fabricating highly efficient MA materials in special self-assembled heterostructures with ternary synergistic effects at the nanoscale.

Surface Molding Hydrogel Film Initiated by ZIF-8 with Ethylene Adsorption Performance for Preserving Perishable Fruits.

The quality deterioration of postharvest fruits is greatly influenced by ethylene, leading to food wastage worldwide. Therefore, it is urgent to develop an efficient packaging strategy to reduce ethylene concentration and prolong the shelf life of perishable fruits. In this work, a surface-molding hydrogel film was created using ZIF-8 in combination with carboxymethyl starch (CMS) and carboxymethyl chitosan (CMCS). Specifically, ZIF-8 is first anchored on CMS and then rapidly cross-linked in situ with CMCS, forming ZIF-8@CC on the fruit surface (within 10 s). The perfect tight-fitting effects of ZIF-8@CC were observed on various fruit surfaces with different roughness (Ra: ranges from 102 to 308 nm). ZIF-8@CC could absorb 57.3% endogenous ethylene from bananas, and the interaction mechanism between ethylene and ZIF-8 was studied by molecular dynamics simulations, providing insights into the ethylene adsorption capacity of ZIF-8@CC. Moreover, ZIF-8@CC presented excellent antibacterial properties and achieved satisfactory ultralong preservation effects on both nonclimatic and climatic fruits (12 days for strawberries and 14 days for bananas) at room temperature. Importantly, ZIF-8@CC is easily removed, washed, and degradable. These findings offer an efficient and potential food packing material with multifunctional properties for preserving perishable fruits.

Cu2-xSe@MXene (Ti3C2Tx) 2D layered heterostructure as an anode for high-performance sodium-ion batteries

With a notable focus on developing efficient sodium storage electrode materials, sodium-ion batteries (SIBs) have been identified as a promising contender in the pursuit of high-performing substitutes for lithium-ion batteries. Among varying sodium storage anode materials for SIBs, nonstoichiometric Cu2-xSe exhibits significant promise. This material stands out due to its ultrahigh electrical conductivity and theoretical sodium storage capacity. However, the practical implementation of Cu2-xSe-based anodes in SIBs is significantly impeded by their sluggish electrochemical reaction kinetics and severe pulverization during the repeated charge–discharge cycles. In the current research, we introduce a novel and straightforward methodology for the synthesis of a heterostructured SIBs anode material (Cu2-xSe@Ti3C2Tx), by coupling Cu2-xSe nanoparticles with two-dimensional (2D) layered MXene (Ti3C2Tx). The 2D layered Ti3C2Tx can provide abundant fast Na+ transport pathways, which effectively promote the ion transport kinetics in the composite anode. Moreover, the pulverization of Cu2-xSe can be effectively mitigated due to the interlamellar spatial confinement of the 2D layered MXene matrix. Consequently, the electrochemical performances of the Cu2-xSe-based anode are significantly improved. Concretely, the Cu2-xSe@Ti3C2Tx anodes demonstrate remarkable rate performance (248mAh g−1 at 10.0 A/g), along with commendable cycling stability, exhibiting a capacity retention of 92 % at 5.0 A/g after 750 cycles. A comprehensive assessment of the Cu2-xSe@Ti3C2Tx anode has been conducted by assembling a full SIB alongside a Na3V2(PO4)3 cathode. This comprehensive study underscores the significant potential of Cu2-xSe-based composite materials, positioning it as a promising candidate for future advancements in SIB technology.

Passively mode-locking fiber laser based on Cr2Si2Te6 saturable absorber

This paper reports on the generation of third-order harmonic mode-locking, double-pulse phenomena, and conventional solitons in an erbium-doped fiber laser using Cr2Si2Te6 as a saturable absorber (SA). The double-balance probing method was employed to examine the nonlinear characteristics of Cr2Si2Te6-SA. Its modulation depth is 2.35 %, and its saturation intensity is 29.74 MW/cm2. We discovered conventional soliton functioning with a center wavelength of 1561.8 nm at a pump power of 34.76 mW. It has a repetition frequency of 6.76 MHz and a signal-to-noise ratio of 45 dB. As the pump power increased, the traditional soliton was able to maintain its existence in the range of 34.76 mW to 80.96 mW. The maximum output power reaches 1.1 mW when the pump power is 80.96 mW, and the maximum single-pulse energy of the conventional soliton is 0.16 nJ. Furthermore, we observed third-order harmonic mode-locking and double-pulse phenomena at pump outputs of 53.65 mW and 71.16 mW. The experimental findings demonstrate the excellent nonlinear effect of the SA based on Cr2Si2Te6. In ultrashort-pulse fiber lasers, Cr2Si2Te6 nanosheets can be employed as an efficient saturable absorption material.

Adjustable Humidity Response: Ultrahigh Green EMI Shielding Gel with Double‐Side Constant Temperature Capability

AbstractWith the increasingly serious secondary pollution of electromagnetic waves (EMWs), efficient green shielding materials have become an urgent need. MXene is widely used in electromagnetic interference (EMI) shielding due to its large surface area and high conductivity. Here, this work constructs MXene islands with better shielding performance through viscosity control and continuous mechanical stirring. Benefiting from the MXene islands, Janus‐structural gel with humidity response is successfully prepared, showing controllable ultrahigh green shielding property (up to 100.5 dB, thickness of 2 mm). Interestingly, this gel can spontaneously adjust its water content according to the humidity, resulting in a reversible transformation in three states to meet the needs of different environments. By Janus‐structural design and reasonable material combination, this gel demonstrates excellent electrothermal (rise to 111.6 °C, 5 s, 2 V)/thermal insulation (thermal conductivity is low to 0.029 W m−1 K−1) properties to meet the needs of shielding in underwater/fire operations.

In situ constructing p-n heterojunction NiCo-MOF/LDH with built-in electric field for wide response range of glucose sensing

The development of non-precious metal nanomaterial for glucose sensor with sensitive performance and broad detection range will be a great challenge. In this study, a p-n heterojunction catalyst (NiCo-MOF/LDH) is devised as an efficient electrocatalytic oxidation material for glucose detection in alkaline solutions. As an enzyme-free sensor of glucose, (NiCo-MOF/LDH) exhibits good electrochemical properties with high sensitivity of 27.76 μA mM−1 cm−2, a low detection limit of 8 µM at a signal-to-noise ratio of 3 and a wide linear range (40 μM-16 mM). The results indicate that the Mott-Schottky junction between NiCo-MOF and NiCo-LDH constructs the built-in electric field (BEF) and achieves the redistribution of surface charge. The local positive charge induced by the p-n junction allows the NiCo-MOF side to adsorb more OH−, and the local negative charge allows the NiCo-LDH side to adsorb glucose positively charged H, optimizing the adsorption reactants and key intermediates. At the same time, the sensor is successfully applied to the detection of glucose in actual sample samples. Hence, the p-n heterojunction NiCo-MOF/LDH provides a rational strategy for a non-enzymatic glucose sensing catalyst.

Liquid nitrogen quenching-induced grain boundary-rich intermetallic compound/metal/carbon composites for efficient capacitive deionization

In this work, a novel liquid nitrogen quenching treatment is introduced for the first time to design and prepare a grain boundary-rich intermetallic compound/metal/carbon composite, serving as an efficient electrode material for sodium ion removal from simulated seawater. The liquid nitrogen quenching method effectively enhances the grain boundary density within the composite due to the rapid cooling-induced forces, thereby creating abundant active sites. Consequently, Co7Fe3/Co/C-700 achieves optimal performance in sodium ion embedding and de-embedding, with a capacity of 207.5 mg/g. Furthermore, sodium ion adsorption/desorption mechanisms are substantiated through ex-situ techniques, revealing dynamic atomic and electronic structure evolutions under operational conditions. Density Functional Theory (DFT) calculations validate the pivotal role of grain boundary sites in enhancing activity, elucidating the correlation between sodium ion adsorption and grain boundaries. Overall, this work elucidates the significant correlation between adsorption behavior and grain boundaries, proposing an innovative strategy for developing electrode materials for capacitive deionization.

Machine learning assisted prediction of absorption maxima in cyclohexene: A comparison using molecular descriptors and fingerprints

Light absorption plays important role in different photovoltaics devices. Easy and fast prediction of absorption properties is essential for fast screening of efficient materials. In our pursuit of identifying the optimal model for predicting absorption maxima, we systematically evaluated over 40 machine learning models, employing both molecular descriptors and fingerprints as input features. Notably, models trained on molecular descriptors demonstrated superior predictive capabilities as compared to those relying on molecular fingerprints. This not only showcased the efficacy of molecular descriptors but also highlighted the potential of these models as rapid and efficient alternatives to the density functional theory (DFT) based approaches. The use of machine learning models based on molecular descriptors introduced a level of simplicity and speed in predictions, surpassing the computational demands associated with traditional DFT-based methods. Our introduced framework that is based on machine learning, offers a valuable tool for the easy and fast prediction of properties.

Sustainable and Reusable Modified Membrane Based on Green Gold Nanoparticles for Efficient Methylene Blue Water Decontamination by a Photocatalytic Process.

Methylene blue (MB) is a dye hazardous pollutant widely used in several industrial processes that represents a relevant source of water pollution. Thus, the research of new systems to avoid their environmental dispersion represents an important goal. In this work, an efficient and sustainable nanocomposite material based on green gold nanoparticles for MB water remediation was developed. Starting from the reducing and stabilizing properties of some compounds naturally present in Lambrusco winery waste (grape marc) extracts, green gold nanoparticles (GM-AuNPs) were synthesized and deposited on a supporting membrane to create an easy and stable system for water MB decontamination. GM-AuNPs, with a specific plasmonic band at 535 nm, and the modified membrane were first characterized by UV-vis spectroscopy, X-ray diffraction (XRD), and electron microscopy. Transmission electron microscopy analysis revealed the presence of two breeds of crystalline shapes, triangular platelets and round-shaped penta-twinned nanoparticles, respectively. The crystalline nature of GM-AuNPs was also confirmed from XRD analysis. The photocatalytic performance of the modified membrane was evaluated under natural sunlight radiation, obtaining a complete disappearance of MB (100%) in 116 min. The photocatalytic process was described from a pseudo-first-order kinetic with a rate constant (k) equal to 0.044 ± 0.010 min-1. The modified membrane demonstrated high stability since it was reused up to 20 cycles, without any treatment for 3 months, maintaining the same performance. The GM-AuNPs-based membrane was also tested with other water pollutants (methyl orange, 4-nitrophenol, and rhodamine B), revealing a high selectivity towards MB. Finally, the photocatalytic performance of GM-AuNPs-based membrane was also evaluated in real samples by using tap and pond water spiked with MB, obtaining a removal % of 99.6 ± 1.2% and 98.8 ± 1.9%, respectively.

Boosting selective Cs+ uptake through the modulation of stacking modes in layered niobate-based perovskites

Selective separation of 137Cs is significant for the sustainable development of nuclear energy and environmental protection, due to its strong radioactivity and long half-life. However, selective capture of 137Cs+ from radioactive liquid waste is challenging due to strong coulomb interactions between the adsorbents and high-valency metal ions. Herein, we propose a strategy to resolve this issue and achieve specific Cs+ ion recognition and separation by modulating the stacking modes of layered perovskites. We demonstrate that among niobate-based perovskites, ALaNb2O7 (A = Cs, H, K, and Li), HLaNb2O7 shows an outstanding selectivity for Cs+ even in the presence of a large amount of competing Mn+ ions (Mn+ = K+, Ca2+, Mg2+, Sr2+, Eu3+, and Zr4+) owing to its suitable void fraction and space shape, brought by the stacking mode of layers. The Cs+ capture mechanism is directly elucidated at molecular level by single-crystal structural analyses and density functional theory calculations. This work not only provides key insights in the design and property optimization of perovskite-type materials for radiocesium separation, but also paves the way for the development of efficient inorganic materials for radionuclides remediation.

Bismuth-Tin Core-Shell Particles From Liquid Metals: A Novel, Highly Efficient Photothermal Material that Combines Broadband Light Absorption with Effective Light-to-Heat Conversion.

This study presents a pioneering investigation of hybrid bismuth-tin (BiSn) liquid metal particles for photothermal applications. It is shown that the intrinsic core-shell structure of liquid metal particles can be instrumentalized to combine the broadband absorption characteristics of defect-rich nano-oxides and the high light-to-heat conversion efficiency of metallic particles. Even though bismuth or tin does not show any photothermal characteristics alone, optimization of the core-shell structure of BiSn particles leads to the discovery of novel, highly efficient photothermal materials. Particles with optimized structures can absorb 85% of broadband light and achieve over 90% photothermal conversion efficiency. It is demonstrated that these particles can be used as a solar absorber for solar water evaporation systems owing to their broadband absorption capability and become a non-carbon alternative enabling scalable applications. We also showcased their use in polymer actuators in which a near-infrared (NIR) response stems from theiroxide shell, and fast heating/cooling rates achieved by the metal core enable rapid response and local movement. These findings underscore the potential of BiSn liquid metal-derived core-shell particles for diverse applications, capitalizing on their outstanding photothermal properties as well as their facile and scalable synthesis conditions.

Toward Strong UV-Vis-NIR Second-Harmonic Generation by Dimensionality Engineering of Zinc Thiocyanates.

The precise modulation of the spatial orientations and connection modes of primitives is vital for certain critically important optical functions for nonlinear optical (NLO) materials (specifically, second-harmonic generation (SHG) and optical bandgap); however, we are yet to achieve a sufficient level of control for the designed construction of efficient broadband NLO materials. Exploiting the changes in microscopic polarization that may result from dimensional increase, we propose herein a zero-dimensional (0D)-to-three-dimensional (3D) dimensionality-increase strategy to realize strong broadband SHG responses for the first time. The novel 3D pseudo diamond-like Zn(SCN)2 has been synthesized by removing SHG-inactive [NH4]+ counter cations and H2O molecules that are located between the adjacent discrete [Zn(SCN)4] building blocks within the 0D (NH4)2Zn(SCN)4·3H2O. The 0D-to-3D dimensionality engineering, proceeding from (NH4)2Zn(SCN)4·3H2O to Zn(SCN)2, results in significantly enhanced SHG responses and efficient broadband activity (8 × KH2PO4 @ 1064 nm, 4.18 eV bandgap for the former c.f. 2 × β-BaB2O4 @ 380 nm, 30 × KH2PO4 @ 1064 nm, 2 × KTiOPO4 @ 2100 nm, 4.78 eV bandgap for the latter) from the UV to the NIR regions (SHG@300-1050 nm). Theoretical calculations and crystal structure analyses reveal that the coordination-bond-connected [Zn(SCN)4] building blocks within the diamond-like structure of Zn(SCN)2 are responsible for its giant broadband SHG responses.

Mesoporous structured MoS2 as an electron transport layer for efficient and stable perovskite solar cells.

Mesoporous structured electron transport layers (ETLs) in perovskite solar cells (PSCs) have an increased surface contact with the perovskite layer, enabling effective charge separation and extraction, and high-efficiency devices. However, the most widely used ETL material in PSCs, TiO2, requires a sintering temperature of more than 500 °C and undergoes photocatalytic reaction under incident illumination that limits operational stability. Recent efforts have focused on finding alternative ETL materials, such as SnO2. Here we propose mesoporous MoS2 as an efficient and stable ETL material. The MoS2 interlayer increases the surface contact area with the adjacent perovskite layer, improving charge transfer dynamics between the two layers. In addition, the matching between the MoS2 and the perovskite lattices facilitates preferential growth of perovskite crystals with low residual strain, compared with TiO2. Using mesoporous structured MoS2 as ETL, we obtain PSCs with 25.7% (0.08 cm2, certified 25.4%) and 22.4% (1.00 cm2) efficiencies. Under continuous illumination, our cell remains stable for more than 2,000 h, demonstrating improved photostability with respect to TiO2.

Experimental and computational insights into oxygen vacancy-rich MoO2-x/N-doped carbon nanowires as high-performance cathode for magnesium batteries and magnesium-lithium hybrid batteries

This work aims to develop efficient cathode materials for magnesium based batteries, which are considered promising next-generation energy storage and conversion devices. One major challenge in magnesium based batteries is the strong Coulomb interaction between magnesium ions and cathode materials, which hinders ion storage and diffusion. To overcome this, we designed and synthesized oxygen vacancy-rich MoO2-x/N-doped carbon nanowires (MoO2-x-NC-NWS). The materials were prepared through a controlled synthesis process, ensuring the incorporation of N-doped carbon and oxygen vacancies, which play crucial roles in improving magnesium ion diffusion and storage. The prepared MoO2-x-NC-NWS demonstrated superior energy storage performance, achieving a capacity of 64 mAh/g in magnesium batteries and 263 mAh/g in magnesium-lithium hybrid batteries at a current density of 50 mA/g. Theoretical calculations further confirmed that oxygen vacancies enhance the diffusion capabilities of magnesium and lithium ions, thereby improving the overall energy storage performance. Therefore, the controllable synthesis of defects such as oxygen vacancies and the development of composite cathode materials are clearly effective strategies for enhancing the performance of magnesium-based battery cathodes. Meanwhile, this rational design of MoO2-based nanostructures provides valuable insights into the development of high-performance cathode materials for magnesium-based energy storage systems.

A Mesoscale Comparative Analysis of the Elastic Modulus in Rock-Filled Concrete for Structural Applications

Rock-filled concrete (RFC) is an advanced construction material that integrates high-performance self-compacting concrete (HSCC) with large rocks exceeding 300 mm, providing advantages such as reduced hydration heat and increased construction processes. The elastic modulus of RFC is a critical parameter that directly influences its structural performance, making it vital for modern construction applications that require strength and stiffness. However, there is a scientific gap in understanding the effects of rock size, shape, arrangement, and volumetric ratio on this parameter. This study investigates these factors using mesoscale finite element models (FEMs) with spherical and polyhedral rocks. The results reveal that polyhedral rocks increase the elastic modulus compared to spherical rocks, enhancing RFC’s load-bearing capacity. Additionally, a 5% increase in the elastic modulus was observed when the rockfill ratio was increased from 50% to 60%, demonstrating a direct correlation between rock volume and mechanical performance. Furthermore, the elastic modulus rises significantly in the early stages of placement, followed by a gradual increase over time. Optimal rock sizes and a balanced mix of rock shapes allow for improved concrete flow and mechanical properties, making RFC a highly efficient material for construction. These findings offer valuable insights for designers and engineers looking to optimize RFC for structural applications.