Quaternary System Research Articles

Low-temperature methanation of fermentation gas with Ni-based catalysts in a multicomponent system

A large amount of greenhouse gases, such as carbon dioxide and methane, are released during the production process of bioethanol and biogas. Converting CO2 into methane is a promising way of capturing CO2 and generating high-value gas. At present, CO2 methanation technology is still in the early stage. It requires high temperature (300–400 ℃) and pressure (> 1 MPa), leading to high cost and energy consumption. In this study, a new catalyst, Ni–Fe/Al–Ti, was developed. Compared with the activity of the common Ni/Al2O3 catalyst, that of the new catalyst was increased by 1/3, and its activation temperature was reduced by 100℃. The selectivity of methane was increased to 99%. In the experiment using simulated fermentation gas, the catalyst showed good catalytic activity and durability at a low temperature and atmospheric pressure. Based on the characterization of catalysts and the study of reaction mechanisms, this article innovatively proposed a Ni–Fe/Al–Ti quaternary catalytic system. Catalytic process was realized through the synergism of Al–Ti composite support and Ni–Fe promotion. The oxygen vacancies on the surface of the composite carrier and the higher activity metals and alloys promoted by Fe accelerate the capture and reduction of CO2. Compared with the existing catalysts, the new Ni–Fe/Al–Ti catalyst can significantly improve the methanation efficiency and has great practical application potential.

Hydrogen bond unlocking-driven pore structure control for shifting multi-component gas separation function

Purification of ethylene (C2H4) as the most extensive and output chemical, from complex multi-components is of great significance but highly challenging. Herein we demonstrate that precise pore structure tuning by controlling the network hydrogen bonds in two highly-related porous coordination networks can shift the efficient C2H4 separation function from C2H2/C2H4/C2H6 ternary mixture to CO2/C2H2/C2H4/C2H6 quaternary mixture system. Single-crystal X-ray diffraction revealed that the different amino groups on the triazolate ligands resulted in the change of the hydrogen bonding in the host network, which led to changes in the pore shape and pore chemistry. Gas adsorption isotherms, adsorption kinetics and gas-loaded crystal structure analysis indicated that the coordination network Zn-fa-atz (2) weakened the affinity for three C2 hydrocarbons synchronously including C2H4 but enhanced the CO2 adsorption due to the optimized CO2-host interaction and the faster CO2 diffusion, leading to effective C2H4 production from the CO2/C2H2/C2H4/C2H6 mixture in one step based on the experimental and simulated breakthrough data. Moreover, it can be shaped into spherical pellets with maintained porosity and separation performance.

A new approach to predicting the region of facilitated glass formation in the Sc-Y-Co-Al system

The experimental search for concentration ranges of vitrification in three-component systems requires the study of several thousands of compositions, whereas for four or more alloy's components the task becomes impracticable at all. To reduce material costs, it is vital to develop reliable theoretical methods for predicting glass formation regions in multicomponent metal systems. We have developed a new model for predicting the compositions of quaternary amorphous metallic glasses and applied it to the Sc-Y-Co-Al system. The proposed model parameters Θx−yx,Θx−yy make it possible to predict the location of glass-forming compositions by finding the minimum of the PHSS parameter multiplication by the geometric coefficient Γ1,2(x), Γ1,2y. The alloy with the composition Sc33Y32Co19Al16 was successfully predicted and then cast in the form of a glass rod with a lateral size of 3 mm. According to the results of X-ray diffraction and thermal analysis, the sample Sc33Y32Co19Al16 is an amorphous material with the lowest value of the crystallinity index 4%. The proposed approach can be used as a predictive model for determining glass-forming compositions in various quaternary metal systems.

Phase Equilibria of Quaternary System KCl + BaCl2 + SrCl2 + H2O and Its Ternary Systems at 323 K

Phase Equilibria of Quaternary System KCl + BaCl2 + SrCl2 + H2O and Its Ternary Systems at 323 K

Evaluation of a Simplified Model for Three-Phase Equilibrium Calculations of Mixed Gas Hydrates

In this study, we perform an extensive evaluation of a simple model for hydrate equilibrium calculations of binary, ternary, and limited quaternary gas hydrate systems that are of practical interest for separation of gas mixtures. We adopt the model developed by Lipenkov and Istomin and analyze its performance at temperature conditions higher than the lower quadruple point. The model of interest calculates the dissociation pressure of mixed gas hydrate systems using a simple combination rule that involves the hydrate dissociation pressures of the pure gases and the gas mixture composition, which is at equilibrium with the aqueous and hydrate phases. Such an approach has been used extensively and successfully in polar science, as well as research related to space science where the temperatures are very low. However, the particular method has not been examined for cases of higher temperatures (i.e., above the melting point of the pure water). Such temperatures are of interest to practical industrial applications. Gases of interest for this study include eleven chemical components that are related to industrial gas-mixture separations. Calculations using the examined methodology, along with the commercial simulator CSMGem, are compared against experimental measurements, and the range of applicability of the method is delineated. Reasonable agreement (particularly at lower hydrate equilibrium pressures) between experiments and calculations is obtained considering the simplicity of the methodology. Depending on the hydrate-forming mixture considered, the percentage of absolute average deviation in predicting the hydrate equilibrium pressure is found to be in the range 3–91%, with the majority of systems having deviations that are less than 30%.

Factors Associated With Timeliness and Equity of Access to Outpatient MRI Examinations

ObjectiveThe role of MRI in guiding patients’ diagnosis and treatment is increasing. Therefore, timely MRI performance prevents delays that can impact patient care. We assessed the timeliness of performing outpatient MRIs using the socio-ecological model approach and evaluated multilevel factors associated with delays. MethodsThis institutional review board–approved study included outpatient MRI examinations ordered between October 1, 2021, and December 31, 2022, for performance at a large quaternary care health system. Mean order-to-performed (OtoP) interval (in days) and prolonged OtoP interval (defined as >10 days) for MRI orders with an expected date of 1 day to examination performance were measured. Logistic regression was used to assess patient-level (demographic and social determinants of health), radiology practice-level, and community-level factors associated with prolonged OtoP interval. ResultsThere were 126,079 MRI examination orders with expected performance within 1 day placed during the study period (56% of all MRI orders placed). After excluding duplicates, there were 97,160 orders for unique patients. Of the MRI orders, 48% had a prolonged OtoP interval, and mean OtoP interval was 18.5 days. Factors significantly associated with delay in MRI performance included public insurance (odds ratio [OR] = 1.11, P < .001), female gender (OR = 1.11, P < .001), radiology subspecialty (ie, cardiac, OR = 1.71, P < .001), and patients from areas that are most deprived (ie, highest Area Deprivation Index quintile, OR = 1.70, P < .001). DiscussionNearly half of outpatient MRI orders were delayed, performed >10 days from the expected date selected by the ordering provider. Addressing multilevel factors associated with such delays may help enhance timeliness and equity of access to MRI examinations, potentially reducing diagnostic errors and treatment delays.

Predicting melting temperature of inorganic crystals via crystal graph neural network enhanced by transfer learning

The melting temperature, a crucial material property, is particularly challenging to measure accurately for inorganic crystals. The data-driven approach emerges as a potential solution, although its effectiveness is hindered by the limitation of available data. To counter this challenge, we implement transfer learning, leveraging a vast computational database of atomization energy. We first pre-train a geometric-information-enhanced crystal graph neural network (GeoCGNN) using atomization energies of approximately 36,000 materials that are computed by the density functional theory. Subsequently, the pre-trained model is fine-tuned using melting temperatures measured for 799 crystals, encompassing 83 elements, ranging from unary to quaternary systems. This transfer learning strategy decreases the root mean square error from 407 to 218 K, attesting to a marked improvement in prediction accuracy. Furthermore, transfer learning significantly mitigates error variability across unary, binary, and ternary (or higher-order) systems, thereby enhancing the reliability of predictions across a broader range of crystals. We also show that transfer learning allows effective task adaptation by leveraging representation learned from pre-training. Therefore, it can achieve better prediction performance even with a limited number of data for predicting melting points.

Design of ion-imprinted amino-modified chitosan for selective chromium (Ⅲ) ion removal

Green ion-imprinting technique was applied to construct a Cr(III) ion-imprinted absorbent material from an amino functionalized chitosan derivative. First, nitrogenous organic compounds (GACS) as functional monomer is synthesized by a Schiff base reaction followed by a grafting reaction. In the end, imprinting was completed by cross-linking with epichlorohydrin (ECH) in aqueous media and eluting the coordinated ions with hydrochloric acid to obtain chromium-imprinted polymers (Cr(III)-IIP) with pores. The relevant parameters of the imprinting system were explored, and the superior polymer (Cr(III)-IIP9) has an excellent adsorption capacity 385.89 mg/g, wide pH range adsorption, good adsorption rates and equilibrium times (≤120 min) for Cr(III) ion. Additionally, the kinetic study is best defined in terms of pseudo-second order, while the Freundlich isotherm model fits the data well. Competitive adsorption of the quaternary system of Cr(III)/ Cd(II)/ Ni(II)/ Cu(II) were also investigated, it demonstrated a greater affinity for the Cr(III) ion than other ions. Hence, the imprinting materials prepared by amino functionalized chitosan enhances the adsorption of Cr(III) ions in the simulation of actual water sample. The adsorption mechanism accords with the hard and soft acid and base theory (HSAB), which is expected to be is utilized for the separation of Cr(III) ions in the environment.

A unified surface tension model for multi-component salt, organic, and surfactant solutions.

Despite the fact that the surface tension of liquid mixtures is of great importance in numerous fields and applications, there are no accurate models for calculating the surface tension of solutions containing water, salts, organic, and amphiphilic substances in a mixture. This study presents such a model and demonstrates its capabilities by modelling surface tension data from the literature. The presented equations not only allow to model solutions with ideal mixing behaviour but also non-idealities and synergistic effects can be identified and largely reproduced. In total, 22 ternary systems comprising 1842 data points could be modelled with an overall root mean squared error (RMSE) of 3.09 mN m-1. In addition, based on the modelling of ternary systems, the surface tension of two quaternary systems could be well predicted with RMSEs of 1.66 mN m-1 and 3.44 mN m-1. Besides its ability to accurately fit and predict multi-component surface tension data, the model also allows to analyze the nature and magnitude of bulk and surface non-idealities, helping to improve our understanding of the physicochemical mechanisms that influence surface tension.

ОСНОВНЫЕ СТРАТИГРАФИЧЕСКИЕ РУБЕЖИ В КАЙНОЗОЕ ПРИМОРЬЯ И ИХ ПРОЯВЛЕНИЕ В ЛИТОЛОГИИ И ПАЛЕОФЛОРАХ

Within the territory of Primorye, key sections are discussed and compared to the boundaries between high-ranking stratigraphic subdivisions, including the boundaries between the Cretaceous and Paleogene, Paleogene and Neogene, Neogene and Quaternary systems, as well as the boundaries between series within the systems. The following boundaries can be considered as the most valid: the Eocene/Oligocene boundary, timed with the transition from the coal-bearing Khasanskaya Formation to the coalless tuff-siltstone Fatashinskaya Formation (Khasan Basin); the Paleogene/Neogene boundary, marked by the change in the lithological type of rocks from coal-bearing Upper Oligocene to tuff-siltstones, tuffs forming the base of the Miocene (Rakovka Basin). The Miocene/Pliocene boundary is proposed to be drawn within the basaltic lava complex with sedimentary rock packets forming the Shufan volcanic plateau at the base of the Kedrovskaya stratum. The Pliocene/Quaternary boundary corresponds to the base of the red-colored "pudding" sequence (Spassk Basin). The Cretaceous-Paleogene and Paleocene-Eocene boundaries cannot be determined with acceptable accuracy due to the lack of relevant sections in the region.

Combined toxicity and adverse outcome pathways of common pesticides on Chlorella pyrenoidosa.

Pesticides due to their extensive use have entered the soil and water environment through various pathways, causing great harm to the environment. Herbicides and insecticides are common pesticides with long-term biological toxicity and bioaccumulation, which can harm the human body. The concept of the adverse outcome pathway (AOP) involves systematically analyzing the response levels of chemical mixtures to health-related indicators at the molecular and cellular levels. The AOP correlates the structures of chemical pollutants, toxic molecular initiation events and adverse outcomes of biological toxicity, providing a new model for toxicity testing, prediction, and evaluation of pollutants. Therefore, typical pesticides including diquat (DIQ), cyanazine (CYA), dipterex (DIP), propoxur (PRO), and oxamyl (OXA) were selected as research objects to explore the combined toxicity of typical pesticides on Chlorella pyrenoidosa (C. pyrenoidosa) and their adverse outcome pathways (AOPs). The mixture systems of pesticides were designed by the direct equipartition ray (EquRay) method and uniform design ray (UD-Ray) method. The toxic effects of single pesticides and their mixtures were systematically investigated by the time-dependent microplate toxicity analysis (t-MTA) method. The interactions of their mixtures were analyzed by the concentration addition model (CA) and the deviation from the CA model (dCA). The toxicity data showed a good concentration-effect relationship; the toxicities of five pesticides were different and the order was CYA > DIQ > OXA > PRO > DIP. Binary, ternary and quaternary mixture systems exhibited antagonism, while quinary mixture systems exhibited an additive effect. The AOP of pesticides showed that an excessive accumulation of peroxide in green algae cells led to a decline in stress resistance, inhibition of the synthesis of chlorophyll and protein in algal cells, destruction of the cellular structure, and eventually led to algal cell death.

A data-driven approach to predict the saturation magnetization for magnetic 14:2:1 phases from chemical composition

14:2:1 phases enable permanent magnets with excellent magnetic properties. From an application viewpoint, saturation polarization, Curie temperature, and anisotropy constant are important parameters for the magnetic 14:2:1 phases. Novel chemical compositions that represent new 14:2:1 phases require especially maximum saturation magnetization values at application-specific operating temperatures to provide maximum values for the remanence and the maximum energy density in permanent magnets. Therefore, accurate knowledge of the saturation magnetization Ms is important. Ms gets affected by chemical composition in a twofold way, with chemical composition significantly influencing both magnetic moments and crystal structure parameters. Therefore, for magnetic 14:2:1 phases, we have developed a regression model with the aim to predict the saturation magnetization in [µB/f.u.] at room temperature directly from the chemical composition as input features. The dataset for the training and testing of the model is very diverse, with literature data of 143 unique phases and 55 entries of repeated phases belonging to the ternary, quaternary, quinary, and senary alloy systems. Substitutionally dissolved elements are heavy and light rare earth elements, transition metals, and additional elements. The trained model is a voting regressor model with different weights assigned to four base regressors and has generalized well, resulting in a low mean absolute error of 0.8 [µB/f.u.] on the unseen test set of 52 phases. This paper could serve as the basis for developing novel magnetic 14:2:1 phases from chemical composition.

Thermodynamic databases of Ti-Al-Fe-V quaternary alloy systems and its application

Pandat software based on Calculations of phase diagram (CALPHAD) was used in this study. Six binary systems and four ternary systems in the Ti-Al-Fe-V system were evaluated, compared, and optimized. A thermodynamic database of Ti-Al-Fe-V titanium alloys was established by selecting the most recent, accurate, and self-consistent thermodynamic parameters. The database was used to simulate the organization of equilibrium solidification and non-equilibrium solidification alloys of Ti-10V-2Fe-3Al, Ti-10V-3Al-1Fe and Ti-10V-3Al. The precipitated phase fractions of Ti-10V-2Fe-3Al at different temperatures were calculated using the database. The effect of different Fe contents and aging temperatures on the phase composition of the Ti-10V-2Fe-3Al alloy is given in conjunction with the calculated results. There is good agreement with the experimental results for the heat treatment regimens given by the calculations. The above results show that thermodynamic calculations based on phase diagrams can guide the formulation of process parameters for alloy casting and heat treatment. The established thermodynamic database for Ti-Al-Fe-V titanium alloys is accurate and reliable.

Synergetic effect of binary, ternary and quaternary binders on microstructural, mechanical and durability aspects of EAF aggregate HPC system

The present study focuses on the combined effects of binder composites on the microstructural, mechanical, and durability characteristics of high-performance concrete that include manufactured sand (M-sand) and Electrical Arc Furnace slag (EAF) aggregate. Also, the influence of multi binders like Ordinary Portland Cement (OPC), Ground Granulated Blast Furnace Slag (GGBS), mS (micro-silica) and nano-silica (nS) have been investigated. The ternary binder system is used to develop HPC mixtures with the effect of the mS in three levels 5%, 10%, and 15% and a quaternary binder system with 1% nS into the optimized ternary system containing 10% mS. Micro-characterization has revealed that the addition of micro-silica (mS) and nano-silica (nS) refined the compact morphology of the multi binder system. Natural aggregate is replaced at the level of 0%, 50%, and 100% with the EAF aggregate. Slump flow value decreased with an increase in micro and nano particles. Mechanical properties of HPC mixes with EAF, as well as a ternary binder without ns and quaternary binder with ns have shown better strength properties due to the combined effect of mS and nS as well as the stronger physical features of EAF slag aggregate. The qualitative tests have shown that the addition of a quaternary binder system has a significant positive effect on the permeable characteristics of HPC mixes. Deterioration due to MgSO4 solution and HCl acid is reduced due to the addition of ternary and quaternary binder composite. The drying shrinkage of HPC mixes was higher with the inclusion of micro and nanoparticles, but the same decreased with the addition of EAF aggregate. The present finding has revealed that the maximum utilization of EAF aggregate and M-Sand enhanced the durability of concrete.

Using the zirconium­containing binders for obtaining refractory concretes

Now the creation of new heat­resistance and refractory binding materials contributing towards reliable and durable service of high­temperature plants is paid great attention. To develop the physical and chemical principles of such materials technology first of all it is necessary to study the high­melting oxide systems and as a consequence, to obtain refractory products in terms of ones. Taking into consideration all mentioned above, the multicomponent zirconium­oxide systems are of potential interest.&#x0D; As a result of our investigations new compositions of high­strength, heat­resistance, and refractory zirconium­containing binders on the basis of different sections of the quaternary system CaO—Al2O3—ZrO2—SiO2 are obtained. Refractory concretes in terms of zirconium­containing cement and various aggregates, both natural (corundum, baddeleyite) and artificial (calcium zirconate), have been elaborated. It is revealed that the kind and granulometric composition of aggregates, molding methods, as well as cement­aggregate relation influence the physical and mechanical properties of concrete developed. Concretes obtained are characterized by high strength (50—60 MPa) and service property stability: refractoriness — more than 1700 °C thermal shock resistance — more than 30 cycles; thermal linear expansion coefficient — 4.8×10–6 ÷ 5.6×10–6 deg.–1, initial strain point under load of 0.2 MPa — 1400—1500 °C Materials developed comply with requirements to refractory materials and can be applied for monolithic linings of heat density parts of high­temperature plants.

Long-lived shallow crustal magma reservoirs beneath Ulleung Island volcano (South Korea) and their rejuvenation recorded in zircon

The microanalytical data obtained from zircons collected on Ulleung Island, an emergent peak of a Quaternary alkaline magma system in the southwestern East Sea (Sea of Japan) back-arc basin, provide new insights into the origin of magma, magmatic processes, and the trigger of explosive eruptions. The U-Th ages of zircons extracted from a pumice layer formed during the intense Plinian eruption at ∼11 ka, known as the Ulleung-Oki tephra, show a wide range spanning the pre-eruption equilibrium state (>350 ka) up to the eruption event itself. Zircon grains derived from syenite and gabbro fragments entrained within the tephra yield weighted mean U-Th and U-Pb ages of 34.7 ± 2.3 ka and 1378 ± 22 ka, respectively. Under cathodoluminescence, zircons from the syenite reveal dark, featureless, or oscillatory-zoned cores, containing numerous inclusions of britholite-like Y-rich phases and pyrochlore. These cores are partially or entirely replaced by inclusion-free, brighter domains, suggesting that in situ dissolution and precipitation processes significantly influenced the transformation of zircon. The consistently low δ18O values (5.4–2.6‰) of zircons from Middle Pleistocene trachyte lavas, the Ulleung-Oki tephra, and lithic fragments indicate the persistent presence of shallow crustal magma reservoirs beneath Ulleung Island. These reservoirs have undergone substantial assimilation of hydrothermally altered rocks, with assimilation rates typically around 10–30% and reaching a maximum of approximately 50%. Zircon core-to-rim variations in oxygen isotopic composition, along with textural observations, suggest the rejuvenation of magma reservoirs through the injection of new melt, which likely served as a trigger for the explosive eruptions at Ulleung Island. The similarity in the range of εHf values between the core and rim (+7.4 to −4.3) implies the Hf isotopic consistency of the recharge melt.

(Invited) Enhanced Material Durability of Transition Metal-Antimony X-Ide Nanoparticles in Oxygen Reduction Electrocatalysis

Hydrogen fuel cells (FCs) are key energy devices that can accelerate our transition away from non-renewable, carbon-intensive fuels especially in the grid-scale storage and transportation sectors. FC cathodes perform the oxygen reduction reaction (ORR), and despite decades of progress towards higher performance electrocatalysts, the ORR remains kinetically sluggish and limits the efficiency of assembled FC devices. Modern, commercially available FC cathodes typically contain platinum (Pt)-based catalysts that can cause the overall FC to become prohibitively expensive for some applications so identifying alternate non-platinum group ORR catalyst formulations could increase deployment of FCs. Physics-based calculations with density functional theory (DFT) have predicted many first-row transition metal oxides (MOx, M = Mn, Fe, Cr, Ni, Co) as having favorable ORR performance trends. Additionally, there is experimental validation of nanoscale ternary and quaternary transition metal oxide systems with a mixture of transition metals used for catalyzing the ORR where relatively modest activity enhancements are reported. Despite this progress, an important limitation is present in the low material stability of non-precious transition metal oxides especially in acidic environments such as those encountered in proton exchange membrane FCs. Using synthetic material strategies to overcome such stability limitations in a variety of FC operating conditions will provide a deeper understanding of the relationship between structure, activity, and degradation.In this work, we employ two simultaneous strategies to work towards enhancing the activity and stability of transition metal oxides: (1) addition of antimony (Sb) as a ligand and (2) functionalization with nitrogen or sulfur. We utilized a previously reported colloidal synthesis for uniform ~ 50 nm oxide nanoparticles for manganese, nickel, cobalt, and iron to produce four sets of nanoparticles based on each of these metals. By using a colloidal synthesis that concurrently introduces Sb with the secondary metal and drying the particles afterwards, we incorporate Sb evenly throughout the polycrystalline structure of the of these nanoparticle catalysts. A high temperature surface modification reaction with reactive gas such as air, ammonia, or hydrogen sulfide was used to convert any remaining transition metal antimonate into an oxide, nitride, or sulfide, respectively. In total, twelve materials are used in this study: the oxide, nitride, and sulfide (collectively “X-ides”) of each of the four transition metal containing, antimony incorporated nanoparticles. We optimize this material synthesis and evaluate the nanoparticle catalyst’s ability to enhance electrochemical ORR activity in both acidic (pH 1) and alkaline (pH 13) conditions which are simulating operating conditions of proton-exchange membrane and anion-exchange membrane FCs, respectively. In addition to activity modulation, we measure the ORR selectivity change towards hydrogen peroxide formation for each material and note the role of nitrogen and sulfur modification in suppressing hydrogen peroxide formation in alkaline environments. In addition to electrochemical characterization, we employed a vast array of bulk and surface characterization techniques to understand catalyst dynamics and contextualize observed activity trends. Transmission electron microscopy (TEM) enabled determination of particle sizes and morphologies alongside electron diffraction patterns to validate the catalyst synthesis. X-ray diffraction (XRD) then provided further information about crystallinity that connected bulk-level insights to the local information from TEM. X-ray photoelectron spectroscopy (XPS) enabled determination of oxidation state changes in the transition metal and in Sb that serve as important descriptors for estimating the activity of these catalysts. We also employed in situ/operando techniques to probe catalyst dynamics and stability under various conditions. Using manganese K-edge synchrotron x-ray absorption spectroscopy (XAS) on the manganese antimony X-ides, we find significant changes to oxidation state and coordination of manganese in the nitride and sulfide as a function of potential indicating processes that displace nitrogen and sulfur in the lattice under certain conditions. Lastly, we use an in situ electrochemical flow cell coupled to inductively coupled plasma-mass spectrometry (ICP-MS) to measure corrosion as a function of ORR current density, potential sweeping, and electrolyte gas saturation to determine degradation patterns. Insights from all these techniques provide a fascinating perspective on what factors in a material and its environment are responsible for enhanced activity, selectivity, and stability. We perform DFT modeling of these systems to further elucidate material properties that are principally responsible for achieving key metrics in activity and stability especially as non-precious catalysts are evaluated for their performance in assembled device conditions. Combining electrochemical experiments, physics-based modeling, and material characterization to better understand structure-performance relationships is a promising path towards accelerating the process of materials discovery for eventual deployment in critical energy applications for the future.

Molten Salt Based High Entropy Electrolytes for Calcium Batteries

Calcium (Ca) is in principle a very attractive metal anode for rechargeable batteries due to the large abundance of calcium in the Earth’s crust, its low electrochemical potential, and its low cost1. Until rather recently2, however, stable plating and stripping of Ca and hence rechargeability of Ca-batteries was deemed impossible, due to the stable phases formed at the electrolyte/electrode interface, completely blocking Ca2+ transfer3.Since this pivotal breakthrough, Ca-batteries have attracted more interest, but they are still in their very infancy and new battery designs – such as using novel electrolyte concepts – are needed to achieve stable cycling of Ca metal anodes, and this preferably at room temperature.Here we report on the use of molten salt electrolytes, i.e. binary and multi-component systems of inorganic cations and anions, and more specifically on their physico-chemical and electrochemical properties as a function of composition with special emphasis on the compositional entropy. By using completely solvent-free electrolytes issues associated with organic electrolytes and solvents, such as the blocking of Ca2+ transfer and electrolyte flammability3, are avoided. Furthermore, they should/do not induce any large polarization, as opposed to ionic liquid-based electrolytes4.In more detail, using the Ca(FSI)2 salt in combination with the analogous Li-, Na-, and KFSI salts in equimolar compositions, all with melting temperatures (significantly) above 100 °C, we can create electrolytes melting at ca. 60-75 °C for the ternary systems, which is further reduced to ca. 55 °C for the quaternary system. These lowered melting temperatures are achieved by increased entropy of mixing, reducing the Gibbs free energy. This can for example be illustrated by Raman spectroscopy via comparing the spectra of “as cast” electrolytes with the spectra for the ones “aged” for one week (Figure 1). Here the FSI anion band at 772 cm-1 (νsS-N-S)5 shows that the electrolytes partially (re-)crystallize/micro-separate for the ternary systems, but stay more stable for the quaternary system, which we, at least partially, attribute to an entropy effect. Reference s M. E. Arroyo-De Dompablo, A. Ponrouch, P. Johansson, and M. R. Palacín, Chem . Rev., 120, 6331–6357 (2020).A. Ponrouch, C. Frontera, F. Bardé, and M. R. Palacín, Nat. Mater., 15, 169–172 (2016).D. Aurbach, R. Skaletsky, and Y. Gofer, J . Electrochem Soc., 138, 3536–3545 (1991).Q. Pang et al., Nature, 608, 704–711 (2022).K. Matsumoto, T. Oka, T. Nohira, and R. Hagiwara, Inorg . Chem ., 52, 568–576 (2013). Figure 1

Mechanical analysis of the incorporation of vanadium atoms into the TiCN system for the conformation of the TiVCN system

Hard coatings are in constant development and evolution, so the generation of new quaternary systems is of great importance. Thus, this research studies the influence of the incorporation of Vanadium atoms into the FCC structure of TiCN, to conform to a quaternary system (TiVCN), which there is very little information so far. The structural analysis evidenced that this quaternary system maintains the same FCC crystal structure as TiCN, and that this structural configuration is in agreement with the models proposed by Hume-Rothery, in which the Titanium and Vanadium atoms randomly occupy the Wyckoff 4a positions and the Carbon and Nitrogen atoms occupy the Wyckoff 4b position. Since Ti and V atoms have a difference in atomic radius, they cause a distortion of the crystal lattice, which will modify the mechanical properties. Experimental results determined a 60 % decrease in roughness, and a 26 % increase in hardness for the TiVCN system compared to TiCN. Thus, this new quaternary system will be a better option to be implemented as protective coatings compared to conventional systems such as TiCN.

X-ray attenuation performance of a newly synthesized tellurium based lead-free radiation shielding glass system

The lead-free quaternary glass systems containing B2O3–CaO–ZnO–TeO2 were synthesized using the traditional melt-quenching method. XRD analysis confirmed that the TeZnCaB glass system exhibited an amorphous behaviour. The density of the glass samples was increased from 3.48 g/cc to 4.08 g/cc by increasing the TeO2 concentration from 20 to 45 mol%. From UV–visible spectroscopy, it was observed that direct and indirect energy band gaps decreased with increasing the TeO2 concentration whereas the refractive index increased. TEM analysis revealed the amorphous behaviour along with nanocrystals present in the glass sample. X-ray attenuation measurements were performed to assess the radiation shielding properties of the lead-free glass system and observed that the radiation shielding capacity was increased with the TeO2 concentration. The best lead equivalent thickness was 2.02 mm for the sample with 45% TeO2 and these glasses could be promising materials for medical diagnostic applications.