Characterization Of Materials Research Articles

Advanced Triboelectric Applications of Biomass-Derived Materials: A Comprehensive Review.

The utilization of triboelectric materials has gained considerable attention in recent years, offering a sustainable approach to energy harvesting and sensing technologies. Biomass-derived materials, owing to their abundance, renewability, and biocompatibility, offer promising avenues for enhancing the performance and versatility of triboelectric devices. This paper explores the synthesis and characterization of biomass-derived materials, their integration into triboelectric nanogenerators (TENGs), and their applications in energy harvesting, self-powered sensors, and environmental monitoring. This review presents an overview of the emerging field of advanced triboelectric applications that utilize the unique properties of biomass-derived materials. Additionally, it addresses the challenges and opportunities in employing biomass-derived materials for triboelectric applications, emphasizing the potential for sustainable and eco-friendly energy solutions.

Carbon aerogel supported Ni–Fe catalysts for superior oxygen evolution reaction activity

AbstractElectrochemical water splitting presents an optimal approach for generating hydrogen (H2), a highly promising alternative energy source. Nevertheless, the slow kinetics of the electrochemical oxygen evolution reaction (OER) and the exorbitant cost, limited availability, and susceptibility to oxidation of noble metal-based electrocatalysts have compelled scientists to investigate cost-effective and efficient electrocatalysts. Bimetallic nanostructured materials have been demonstrated to exhibit improved catalytic performances for the oxygen evolution reaction (OER). Herein, we report carbon aerogel (CA) decorated with different molar ratios of Fe and Ni with enhanced OER activity. Microwave irradiation was involved as a novel strategy during the synthesis process. Inductively coupled plasma mass spectrometry (ICP-MS), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope (SEM), Energy dispersive X-ray spectroscopy (EDAX spectra and EDAX mapping), Transmission Electron Microscope (TEM), High-Resolution Transmission Electron Microscope (HR-TEM), and Selected Area Electron Diffraction (SAED) were used for physical characterizations of as-prepared material. Electrochemical potential towards OER was examined through cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy (EIS). The FeNi/CA with optimized molar ratios exhibits low overpotential 377 mV at 10 mAcm−2, smaller Tafel slope (94.5 mV dec−1), and high turnover frequency (1.09 s−1 at 300 mV). Other electrocatalytic parameters were also calculated and compared with previously reported OER catalysts. Additionally, chronoamperometric studies confirmed excellent electrochemical stability, as the OER activity shows minimal change even after a stability test lasting 3600 s. Moreover, the bimetallic (Fe and Ni) carbon aerogel exhibits faster catalytic kinetics and higher conductivity than the monometallic (Fe), which was observed through EIS investigation. This research opens up possibilities for utilizing bi- or multi-metallic anchored carbon aerogel with high conductivities and exceptional electrocatalytic performances in electrochemical energy conversion.

Structural, microstructural, dielectric, electrical, and magnetic properties of a scandium-modified bismuth ferrite

ABSTRACT This paper reports on the synthesis method and characterisation of a binary polycrystalline material (Pb0.6Bi0.2Sc0.2)(Fe0.4Ti0.6)O3 ceramic. The room temperature XRD pattern confirms an orthorhombic crystal structure with average crystallite size of 25.3 nm. Study on SEM micrograph reveals the homogeneous dispersal of grains and well-defined grain boundaries and also the compactness of the grains implies the development of a highly dense material. The purity and composition of this material are verified using EDX, and confirms presence of all the constituent elements (Pb, Bi, Sc, Fe, Ti, and O) both in weight and atomic percentage. According to research on dielectric spectra as a function of temperature range of 25°C to 500°C and frequency range of 1 kHz to 1 MHz, there may be Maxwell–Wagner-type dispersion at low frequencies, which considerably decreases towards higher frequencies because of decreasing space charge polarisation. The negative temperature coefficient of resistance behaviour is observed from impedance spectroscopy. The research of modulus spectroscopy demonstrates the existence of a non-Debye type of relaxation. The thermally activated charge carriers regulate the study of the conduction mechanism. The semicircular arcs found both in Nyquist and Cole–Cole plots provide an evidence for the semiconducting nature. The magnetic study reveals the superparamagnetic nature of the sample.

Nano-Raman Spectroscopy of 2D Materials

Abstract The use of nano-Raman spectroscopy to study two-dimensional (2D) systems is presented here. The nano (tip-enhanced) Raman spectroscopy (TERS) technique is briefly introduced, addressing some new theoretical aspects for Raman spectroscopy in the near-field regime, including field coherence, field distribution and the relevance of atomic description and quenching effects. State-of-the-art results in graphene and transition metal dichalcogenides are presented, exploring the connection between micro- and nano-Raman metrology. Various aspects such as defects, homojunctions, twisted-bilayer structures, localized emissions at bubbles, wrinkles, and borders, as well as substrate and coherence effects are addressed in detail. The paper concludes by outlining the perspectives for nano-Raman spectroscopy in 2D systems, highlighting its potential for advancing our understanding of nanoscale phenomena and facilitating further breakthroughs in materials science and characterization.

Characterization of Anisotropic Salt Weathering through Nondestructive Techniques Mapping Using a GIS Environment.

Doctrinal texts on architectural heritage conservation emphasize the importance of fully understanding the structural and material characteristics and utilizing information systems. Photogrammetry allows for the generation of detailed, geo-referenced Digital Elevation Models of architectural elements at a low cost, while GIS software enables the addition of layers of material characteristic data to these models, creating different property maps that can be combined through map algebra. This paper presents the results of the mechanical characterization of materials and salt-related decay forms of the polygonal apse of the 13th-century monastery of Santa María de Bonaval (Guadalajara, Spain), which is primarily affected by salt crystallization. Rock strength is estimated using on-site nondestructive testing (ultrasound pulse velocity and Leeb hardness). They are mapped and combined through map algebra to derive a single mechanical soundness index (MSI) to determine whether the decay of the walls could be dependent on the orientation. The presented results show that salt decay in the building is anisotropic, with the south-facing side of the apse displaying an overall lower MSI than the others. The relative overheating of the south-facing side of the apse enhances the effect of salt crystallization, thereby promoting phase transitions between epsomite and hexahydrite.

A Microporous Gel Polymer Electrolyte with High Mg2+ Ionic Conductivity at Room Temperature

Rechargeable magnesium batteries have attracted much attention due to the high theoretical volumetric capacity, abundance, and safety. However, solid‐state Mg batteries have been rarely studied because of limited choices of solid‐state electrolyte materials. In this research, poly(vinylidene fluoride)/poly(propylene carbonate) (PVDF/PPC) as matrix were prepared using a simple solution casting method. Ethylene carbonate (EC), diethyl carbonate (DEC), and magnesium(II) bis(trifluoromethanesulfonyl) imide [Mg(TFSI)2] were selected to prepare liquid electrolyte. A classification of novel gel polymer electrolytes (GPEs), PVDF/PPC/Mg(TFSI)2, was synthesized and investigated. The electrochemical measurements show that PVDF/PPC/Mg(TFSI)2 polymer electrolytes exhibit a high ionic conductivity, close to 10‐2 S cm‐1, at room temperature. The electrochemical stability window of PVDF/PPC‐based GPE was up to 3 V (versus Mg2+/Mg). Materials characterization shows that these GPEs have a porous structure, providing a pathway for magnesium ion transport. Thermal analysis and crystal structure results indicate that PVDF crystallinity was affected by the addition of PPC. Additionally, the ion transport mechanism in the gel polymer electrolyte has been discussed.

Infrared spectroscopy across scales in length and time at BESSY II.

The infrared beamline at BESSY II storage ring was upgraded recently to extend the capabilities of infrared microscopy. The endstations available at the beamline are now facilitating improved characterization of molecules and materials at different length scales and time resolutions. Here, the current outline of the beamline is reported and an overview of the endstations available is given. In particular, the first results obtained by using a new microscope for nano-spectroscopy that was implemented are presented. The capabilities of the scattering-type near-field optical microscope (s-SNOM) are demonstrated by investigating cellulose microfibrils, representing nanoscopic objects of a hierarchical structure. It is shown that the s-SNOM coupled to the beamline allows imaging to be performed with a spatial resolution of less than 30 nm and infrared spectra to be collected from an effective volume of less than 30 nm × 30 nm × 12 nm. Potential steps for further optimization of the beamline performance are discussed.

Synthesis, Characterization, and Properties of Heat-Resistant Energetic Materials Based on C-C Bridged Dinitropyrazole Energetic Materials.

Polycyclic energetic materials make up a distinctive class of conjugated structures that consist of two or more rings. In this work, 1,3-bis(3,5-dinitro-1H-pyrazol-4-yl)-4,6-dinitrobenzene (BDPD) was synthesized and investigated in detail as a polycyclic heat-resistant energetic molecule that can be deprotonated by bases to obtain its anionic (3-5) salts. All compounds were thoroughly characterized by 1H and 13C NMR, infrared spectroscopy, high-resolution mass spectrometry, and elemental analysis. The structural features of BDPD and its salts were investigated by single-crystal X-ray diffraction and analyzed by different kinds of computing software, like Multiwfn, Gaussian 09W, and so on. In addition, their thermal decomposition temperatures were evaluated by differential scanning calorimetry to be 319.8-329.0 °C, revealing that they possessed high thermal stabilities. The results of impact sensitivity and friction sensitivity analysis confirm that these energetic compounds were insensitive. The detonation properties of neutral compound BDPD and all its nonmetallic salts were calculated by the EXPLO5 v6.05.04 program. The results revealed that their detonation performances were higher than those of the widely used heat-resistant explosive 2,2',4,4',6,6'-hexanitrostilbene (HNS). Combining the above results, it is reasonable to suggest that these compounds have the potential to be heat-resistant energetic materials.

Toward Self-Driven Autonomous Material and Device Acceleration Platforms (AMADAP) for Emerging Photovoltaics Technologies.

ConspectusIn the ever-increasing renewable-energy demand scenario, developing new photovoltaic technologies is important, even in the presence of established terawatt-scale silicon technology. Emerging photovoltaic technologies play a crucial role in diversifying material flows while expanding the photovoltaic product portfolio, thus enhancing security and competitiveness within the solar industry. They also serve as a valuable backup for silicon photovoltaic, providing resilience to the overall energy infrastructure. However, the development of functional solar materials poses intricate multiobjective optimization challenges in a large multidimensional composition and parameter space, in some cases with millions of potential candidates to be explored. Solving it necessitates reproducible, user-independent laboratory work and intelligent preselection of innovative experimental methods.Materials acceleration platforms (MAPs) seamlessly integrate robotic materials synthesis and characterization with AI-driven data analysis and experimental design, positioning them as enabling technologies for the discovery and exploration of new materials. They are proposed to revolutionize materials development away from the Edisonian trial-and-error approaches to ultrashort cycles of experiments with exceptional precision, generating a reliable and highly qualitative data situation that allows training machine learning algorithms with predictive power. MAPs are designed to assist the researcher in multidimensional aspects of materials discovery, such as material synthesis, precursor preparation, sample processing and characterization, and data analysis, and are drawing escalating attention in the field of energy materials. Device acceleration platforms (DAPs), however, are designed to optimize functional films and layer stacks. Unlike MAPs, which focus on material discovery, a central aspect of DAPs is the identification and refinement of ideal processing conditions for a predetermined set of materials. Such platforms prove especially invaluable when dealing with "disordered semiconductors," which depend heavily on the processing parameters that ultimately define the functional properties and functionality of thin film layers. By facilitating the fine-tuning of processing conditions, DAPs contribute significantly to the advancement and optimization of disordered semiconductor devices, such as emerging photovoltaics.In this Account, we review the recent advancements made by our group in automated and autonomous laboratories for advanced material discovery and device optimization with a strong focus on emerging photovoltaics, such as solution-processing perovskite solar cells and organic photovoltaics. We first introduce two MAPs and two DAPs developed in-house: a microwave-assisted high-throughput synthesis platform for the discovery of organic interface materials, a multipurpose robot-based pipetting platform for the synthesis of new semiconductors and the characterization of thin film semiconductor composites, the SPINBOT system, which is a spin-coating DAP with the potential to optimize complex device architectures, and finally, AMANDA, a fully integrated and autonomously operating DAP. Notably, we underscore the utilization of a robot-based high-throughput experimentation technique to address the common optimization challenges encountered in extensive multidimensional composition and parameter spaces pertaining to organic and perovskite photovoltaics materials. Finally, we briefly propose a holistic concept and technology, a self-driven autonomous material and device acceleration platform (AMADAP) laboratory, for autonomous functional solar materials discovery and development. We hope to discover how AMADAP can be further strengthened and universalized with advancing development of hardware and software infrastructures in the future.

Advancement in Fabrication and Characterization Techniques of Nanocomposites.

Advancements in the field of materials research have unveiled numerous unparalleled features, such as mechanical properties, clinical advances, interfacial strengthening, and porosities, providing a wide range of applications. The employment of any material begins with fabrication and characterization, demanding expertise for the effective execution of the investigation. This review encompasses the details of the working principles of some significant and frequently used fabrication and characterization techniques for various material categories, including pellets and coatings. The discussion begins with techniques for fabricating materials for various applications. A brief overview of coating synthesis methods can provide intriguing information for researchers in the field of coating fabrication. The report highlights the portrayal of morphological and physiochemical analysis techniques, followed by the estimation of the elastic modulus using nanoindentation and dynamic modulus mapping testing for the materials. Additionally, the review covers theoretical models for observing the elastic moduli of the materials. The review depicts tribological investigations of the materials, aiming to provide insight into fretting wear, pin-on-disc, and microscratch testing. The fundamentals of electrochemical characterization are presented, including the appraisal of linear polarization and potentiodynamic polarization as well as electrochemical impedance spectroscopy. Furthermore, the magnetic behavior was examined by using a vibrating sample magnetometer (VSM), and the estimation of magnetic domains in the materials was conducted through magnetic force microscopy. Thus, the report suggests that readers, especially beginners, can gain a comprehensive understanding of the extensive prospects associated with the fundamental principles of material synthesis and characterization.

Detecting irradiation defects in materials: A machine learning approach to analyze helium bubble images

Additive manufacturing technology has received significant attention in the field of nuclear materials due to its potential to improve the radiation resistance of materials and components. In our research, we propose to use 304 L stainless steel fabricated by Selective Laser Melting (SLM) as a replacement for traditional casting due to its superior performance and optimized manufacturing technique. During testing of its radiation resistance, we found that analyzing helium bubbles captured by transmission electron microscopy (TEM) is crucial for understanding and predicting material behavior under irradiation. However, this task typically involves manual counting, which is both time-consuming and prone to errors due to the fatigue of human annotators. To address this challenge, we present a novel machine learning model for automatic helium bubbles detection and counting through images. Our model leverages a fusion of traditional computer vision techniques with cutting-edge machine learning methods to achieve superior detection of helium bubbles in nuclear materials. This approach is based on two core designs: a novel generative model to generate training data and a gradient convergence layer to limit the range of parameters. Experiments show that our model outperforms previous state-of-the-art unsupervised detectors, and achieves highly accurate helium bubble segmentation in a few-shot scenario, with an F1 score typically exceeding 90 % and an average size error less than 0.1 nm. Our model achieves over 100 times more efficiency than manual counting, which takes approximately 20 s per image. Our work demonstrates a successful collaboration between the fields of material characterization and artificial intelligence (AI). By leveraging the respective strengths of material science and machine learning, we have achieved surprising results that could have a significant impact on the development of new materials and components for nuclear applications.

Study on the Thermal Sensitivity of Anisotropic Thin Sheets: Application to Hot Bulge Tests

This article presents a study on the thermal sensitivity of anisotropic thin sheets, focusing specifically on their behavior during hot bulge tests. Anisotropic materials exhibit different mechanical properties in different directions, and understanding their response to thermal loading is crucial for various engineering applications.
 The experimental investigation involves subjecting thin sheets of anisotropic materials to controlled thermal conditions and measuring their response. The hot bulge test, a well-established method, is employed to analyze the behavior of the sheets under elevated temperatures. This test involves applying a controlled internal pressure to a heated circular and elliptical specimen, causing it to deform and form a bulge.
 Through this study, the thermal sensitivity of anisotropic thin sheets is characterized by analyzing the bulge height, bulge profile, and strain distribution. The influence of various factors, such as temperature, material anisotropy, and loading rate, is examined to understand their effects on the sheet's response.
 Experimental results reveal significant variations in the thermal sensitivity of anisotropic thin sheets, depending on the material's orientation and temperature. The study demonstrates that certain orientations exhibit greater sensitivity to thermal loading, leading to distinct bulge profiles and strain distributions.
 Furthermore, numerical simulations are conducted using finite element analysis to validate and complement the experimental findings. The simulation models incorporate the anisotropic material properties and the thermal boundary conditions, enabling a comprehensive understanding of the thermal sensitivity behavior observed experimentally.
 The outcomes of this study provide valuable insights into the thermal behavior of anisotropic thin sheets, particularly in the context of hot bulge tests. The findings contribute to the knowledge base of material characterization and can aid in the design and optimization of structures and components subjected to thermal loading, where anisotropic materials are involved.

Simulation of the Dynamic Responses of Layered Polymer Composites under Plate Impact Using the DSGZ Model

This paper presents a numerical study on the dynamic response and impact mitigation capabilities of layered ceramic–polymer–metal (CPM) composites under plate impact loading, focusing on the layer sequence effect. The layered structure, comprising a ceramic for hardness and thermal resistance, a polymer for energy absorption, and a metal for strength and ductility, is analyzed to evaluate its effectiveness in mitigating the impact loading. The simulations employed the VUMAT subroutine of DSGZ material models within Abaqus/Explicit to accurately represent the mechanical behavior of the polymeric materials in the composites. The VUMAT implementation incorporates the explicit time integration scheme and the implicit radial return mapping algorithm. A safe-version Newton–Raphson method is applied for numerically solving the differential equations of the J2 plastic flow theory. Analysis of the simulation results reveals that specific layer configurations significantly influence wave propagation, leading to variations in energy absorption and stress distribution within the material. Notably, certain layer sequences, such as P-C-M and C-P-M, exhibit enhanced impact mitigation with a superior ability to dissipate and redirect the impact energy. This phenomenon is tied to the interactions between the material properties of the ceramic, polymer, and metal, emphasizing the necessity of precise material characterization and enhanced understanding of the layer sequencing effect for optimizing composite designs for impact mitigation. The integration of empirical data with simulation methods provides a comprehensive framework for optimizing composite designs in high-impact scenarios. In the general fields of materials science and impact engineering, the current research offers some guidance for practical applications, underscoring the need for detailed simulations to capture the high-strain-rate dynamic responses of multilayered composites.

Efficient phosphate adsorption in aqueous solution using nano-zirconia impregnated spent coffee grounds and preliminary application as a slow-release fertilizer

ABSTRACT In this study, the development of a nano-biocomposite adsorbent based on spent coffee grounds (SCG) and nano-Zirconia (n-ZrO2) was presented to meet the increasing demand for effective and low-cost phosphate adsorbents and contribute to sustainable development goals (SDGs). The adsorption performance of raw SCG and SCG modified with n-ZrO2 (n-ZrO2-mSCG) was tested. The characterization of materials was performed by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), BET surface area analysis, thermogravimetric analysis (TGA), Scanning electron microscopy (SEM), Dispersive X-ray spectroscopy (EDS), and Transmission electron microscopy (TEM). The n-ZrO2-mSCG exhibited superior adsorption capacity compared to SCG. The influences on the adsorption of factors such as initial concentration, pH, stirring time, temperature, and coexisting ions were evaluated. The results showed the maximal adsorption capacity of modified SCG was 15.8 mg/g at pH 2, using a stirring time of 150 mins. Among investigated coexisting anions, sulfate (SO4 2-) and bicarbonate (HCO3 −) affected the phosphate adsorption performance of n-ZrO2-mSCG, when they existed in aqueous solution at predominant levels. The n-ZrO2-mSCG displayed high selectivity toward phosphate and sustained efficacious phosphate adsorption after three successive cycles of adsorption/desorption, proposing a prospective low-cost and reusable adsorbent material for phosphate removal and a potential alternative to conventional fertilizers.

Development, Characterisation and Biocompatibility Analysis of a Collagen-Gelatin-Hydroxyapatite Scaffold for Guided Bone Regeneration

Guided Bone Regeneration (GBR) is the choice of treatment for improving the horizontal and vertical bone volume through bone grafting. GBR membranes work on the principle of preventing epithelial migration into the defect space while maintaining the space for cell migration and differentiation at the defect site. Hydroxyapatite has been commonly used as a bone graft for infrabony defects. The study was conducted at the Department of Biomaterials at Saveetha Dental College. GBR membrane was prepared and its material characterization was done using Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX) analysis, Fourier Transform Infrared Radiation (FTIR), and Confocal Analysis. The developed GBR membrane revealed SEM properties conducive to cell attachment. EDX and FTIR analysis showed the successful development of the collagen-gelatin-hydroxyapatite membrane. Cell culture and confocal analysis revealed excellent biocompatibility with a homogenous layer of viable cells. The developed composite GBR membrane is a biogenic membrane with relevant biomineralization potential that should be applied for GBR applications.

Experimental study of a thin thermally grown oxide layer in thermal barrier coatings based on the SWT-BP algorithm and terahertz technology

As a promising nondestructive testing (NDT) technique with a very adaptive physical modeling of wave transmission process, terahertz technology is used for the detection and characterization of nonpolar materials and the evaluation of layered and/or defective structures. THz-TDS can also be used to perform spectroscopic analysis and detect structural defects in thermal barrier coatings (TBCs) of aero-engines. Although it is generally difficult to measure the structure of the thin oxide layer of the thermal barrier coatings whose thickness is generally lower than 30 µm (the current axial resolution of the THz-TDS cannot exceed 30 µm). We were able to complete the detection of the oxide layer within 1–29 µm through simulation by using the SWT-BP algorithm. In this study, the analysis was performed on real-world samples, the fitting degree of the SWT-BP algorithm reached 0.77, and the minimum prediction error was less than 0.1 µm. The paper also put forward some improvement measures about the experimental results.

Carbon nanospheres-induced enhanced capacitive dynamics in C/WS2/WO3 nanocomposites for high-performance electrochemical capacitors

This work investigates the impact of carbon nanospheres on the electrochemical performance of C/WS2/WO3 nanocomposites for electrochemical supercapacitors. The nanocomposites have been synthesized and characterized by various techniques like XRD, UV–vis spectroscopy, SEM, TEM and FTIR. The electrochemical properties of the nanocomposites have been analysed in order to study the charge transport, reaction kinetics, impedimetric properties and specific capacitance by using cyclic voltammetry (CV) and potentio electrochemical impedance spectroscopy (PEIS). The capacitive performance of the samples has been investigated by the obtained specific capacitance values and Nyquist plots. The specific capacitance of the samples has been found in a range of 0.8–2.8F/g at 20 mV/s. The sample with the least amount of carbon showed maximum specific capacitance. The electrochemical insights, combined with comprehensive material characterizations, provide valuable knowledge for tailoring the capacitive performance of C/WS2/WO3 nanocomposites through controlled carbon nanospheres and thus the suitability of materials for electrochemical capacitors.

Molybdenum Sulfide Nanoflowers as Electrodes for Efficient and Scalable Lithium-Ion Capacitors.

Hybrid supercapacitors (HSCs) bridge the unique advantages of batteries and capacitors and are considered promising energy storage devices for hybrid vehicles and other electronic gadgets. Lithium-ion capacitors (LICs) have attained particular interest due to their higher energy and power density than traditional supercapacitor devices. The limited voltage window and the deterioration of anode materials upsurged the demand for efficient and stable electrode materials. Two-dimensional (2D) molybdenum sulfide (MoS2) is a promising candidate for developing efficient and durable LICs due to its wide lithiation potential and unique layer structure, enhancing charge storage efficiency. Modifying the extrinsic features, such as the dimensions and shape at the nanoscale, serves as a potential path to overcome the sluggish kinetics observed in the LICs. Herein, the MoS2 nanoflowers have been synthesized through a hydrothermal route. The developed LIC exhibited a specific capacitance of 202.4 F g‑1 at 0.25 A g‑1 and capacitance retention of > 90% over 5,000 cycles. Using an ether electrolyte improved the voltage window (2.0 V) and enhanced the stability performance. The ex-situ material characterization after the stability test reveals that the storage mechanism in MoS2-LICs is not diffusion-controlled. Instead, fast surface redox reactions, especially intercalation/deintercalation, are more prominent for charge storage.

Interface behavior in negative current collectors for sodium‖zinc liquid metal batteries: Implications for enhanced energy storage performance

All-liquid structure and elevated operational temperatures of liquid metal batteries (LMBs) cause severe corrosion of the current collector, impacting cycling performance. This investigation explores the interaction behaviors between negative current collectors (Mo, W, Fe) and the negative active material (Na) within Na|NaCl-CaCl2|Zn LMB. Experiment results indicate that the Na|NaCl-CaCl2|Zn LMB with Fe current collector displays higher cycle stability and smaller polarization than that using Mo or W current collector. The capacity fading rates of 1.23 %, 1.03 %, and 0.23 % in 40 cycles for Mo, W, and Fe current collectors, respectively. Characterizations of materials indicate that Fe4Zn9, W-Zn solid solution and MoZn7 are formed on the Fe, W, and Mo interfaces. Theoretical calculations reveal that the adsorption energy of Na atom on Fe/Fe4Zn9 surpassed that on other current collectors, which indicates the superior charge-transfer kinetics of Na+ on the Fe electrode. The high performance of Fe current collector is attributed to the formation of a dense structure of Fe-Zn alloy and fast charge-transfer ability. Our study contributes to a deeper understanding of the intricate electrochemical processes at the negative electrode interface and provides a practical framework for optimizing the performance of Na‖Zn LMBs.

An investigation of the genotoxic potential of a well-characterized yerba mate extract

Yerba Mate (Ilex paraguariensis) is historically used as a beverage and its extracts are considered traditional medicine in South America. Extract use has been expanding to North American and European markets and the currently available genetic toxicology literature indicate discrepancies in genotoxicity findings for yerba mate. As botanical extract use expands, assumption in safety should be made with caution assuring a good understanding of the test material characterization. Authoritative agencies suggest a two-step paradigm to investigate genotoxicity, and this was implemented to evaluate the safety of yerba mate hydroxycinnamic acid extract. Four OECD compliant assays were employed: bacterial reverse mutation, in vitro micronucleus and a parallel in vivo micronucleus, and comet assay. No evidence of mutagenicity was observed in the in vitro Ames assay, but the results of an in vitro micronucleus study were inconclusive. However, oral gavage treatment of rats for the in vivo micronucleus and comet assays demonstrated negative findings. The results from this battery of tests, supports that this yerba mate hydroxycinnamic acid extract is not anticipated to pose genotoxicity concerns. A high-level comparison of results to other available genotoxicity literature on yerba mate is presented with emphasis on the importance of identity when drawing conclusions on botanicals.