Density Functional Molecular Dynamics Simulations Research Articles

An in-depth on the high corrosion resistance of carbon steel in an acidic solution by a novel functionalized graphene oxide with oxime derivative via cutting-edge experimental characterization and computational modeling

Carbon steel is inextricably linked to industrial production and construction owing to its superior durability, low cost, and simplicity of manufacturing. However, it was discovered that carbon steel is very sensitive to corrosion in a variety of harsh environments, the most common of which are acidic solutions, which are frequently used in the surface pickling and oil well acidification sectors. In an acidic environment, carbon steel spontaneously degrades causing significant corrosion difficulties. As a result, research into carbon steel corrosion in aggressive acidic solutions has garnered a lot of attention. The inclusion of a corrosion inhibitor seems to be one of the most efficient techniques for preventing carbon steel corrosion. The current study is concerned with the synthesis of 1,3-diphenylprop-2-en-1-one oxime functionalized graphene oxide (DPPO-GO), which was characterized using FTIR, Raman, and a Scanning Electron Microscope (SEM). Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization curves (PDP), and weight loss measurements were used to investigate the inhibitory effect of functionalized graphene oxide on the corrosion of carbon steel in 0.5 M sulfuric acid solution. Concurrently, the effect of concentrations and the synergistic effect were explored. According to the PDP results, the DPPO-GO behave as mixed-type inhibitors. At the optimum dose of 60 mg/L, EIS measurements revealed that functionalized graphene oxide exhibited a great protective capacity reaching 94%. Adsorption experiments demonstrated that the DPPO-GO displayed both physisorption and chemisorption processes, corresponding to the Langmuir model. By computing the synergism parameter, the synergistic influence of DPPO-GO and KI was determined. Under diverse settings, the surface morphology of carbon steel was investigated using SEM and UV–visible. Calculations based on density functional theory, Monte Carlo, and Molecular dynamic simulations were utilized to further investigate the inhibitory impact.

Shape Control of Carbon Nanoparticles via a Simple Anion‐Directed Strategy for Precise Endoplasmic Reticulum‐Targeted Imaging

AbstractHerein, small‐sized fluorescent carbon nanoparticles (CNs) with tunable shapes ranging from spheres to various rods with aspect ratios (ARs) of 1.00, 1.51, 1.89, and 2.85 are prepared using a simple anion‐directed strategy for the first time. Based on comprehensive morphological and structural characteristics of CNs, along with theoretical calculations of density functional theory and molecular dynamics simulations, their shape‐control mechanism is attributed to interionic interactions‐induced self‐assembly, followed by carbonization. The endoplasmic reticulum‐targeting accuracy of CNs is gradually enhanced as their shape changes from spherical to higher‐AR rods, accompanied by a Pearson's correlation coefficient up to 0.90. This work presents a facile approach to control the shape of CNs and reveals the relationship between the shape and organelle‐targeting abilities of CNs, thereby providing a novel idea to synthesize CNs that serve as precise organelle‐targeted fluorescent probes.

Shape Control of Carbon Nanoparticles via a Simple Anion-Directed Strategy for Precise Endoplasmic Reticulum-Targeted Imaging.

Herein, small-sized fluorescent carbon nanoparticles (CNs) with tunable shapes ranging from spheres to various rods with aspect ratios (ARs) of 1.00, 1.51, 1.89, and 2.85 are prepared using a simple anion-directed strategy for the first time. Based on comprehensive morphological and structural characteristics of CNs, along with theoretical calculations of density functional theory and molecular dynamics simulations, their shape-control mechanism is attributed to interionic interactions-induced self-assembly, followed by carbonization. The endoplasmic reticulum-targeting accuracy of CNs is gradually enhanced as their shape changes from spherical to higher-AR rods, accompanied by a Pearson's correlation coefficient up to 0.90. This work presents a facile approach to control the shape of CNs and reveals the relationship between the shape and organelle-targeting abilities of CNs, thereby providing a novel idea to synthesize CNs that serve as precise organelle-targeted fluorescent probes.

Prediction of cosolvent effect on solvation free energies and analysis of intermolecular forces of tizanidine hydrochloride in ethyl acetate + methanol / ethanol mixtures

The solubility of small molecule drug in solvents can be dramatically affected by addition of a suitable cosolvent, which makes the screening of the best-suited cosolvent an important task for the purification and preparation. The present work aims to improve the fundamental understanding of tizanidine hydrochloride (TIZ HC) solvation by cosolvent. Solubility experimental data from TIZ HCl in mixtures of ethyl acetate + alcohols were obtained at different temperatures with the method of isothermal equilibrium. In the system of ethyl acetate + methanol, the solubility data increased firstly and then decreased with an increase in ethyl acetate content, however, the strictly monotonic decreasing of solubility in ethyl acetate + ethanol mixtures was observed. The solubility correlation fitting was performed with the Jouyban-Acree model and CNIBS/R-K model. The solvent effect analysis indicates that the hydrogen bond acidity, the polarity / polarizability and the cohesive forces of the solvent have a greater influence on the solubility, which was further validated by the local quantitative molecular surface analysis results of electrostatic potential (ESP). The dissolution process of TIZ HCl in systems with different solvent compositions was analyzed in the form of preferential solvation parameters, it was found that methanol is the preferred solvent in the solvation shell of TIZ HCl in methanol-rich and ethyl acetate-rich mixtures but the ethanol is preferred in intermediate compositions and ethyl acetate-rich mixtures. Moreover, the types of intermolecular solute–solvent interactions were discussed on the basis of the structural characteristics of TIZ HCl. The solvation free energy is a key parameter describing solvent effects, which is extremely important for understanding solution chemistry. For this part, with the aid of density functional theory (DFT) and molecular dynamics (MD) simulations, it was found that the cosolvent effect is consistent with the prediction trend of solvation free energy of TIZ HCl in each systems. The effect of the cavity formed by the solvent molecules and dipole moment of solute was calculated accordingly by the solvation model based on density (SMD) for explaining the former behavior.

Double Effects of Oxidative Aging on Carbon Nanotube-Asphalt Nanocomposite Interfaces: Enhancement and Deterioration.

Understanding the mechanisms of oxidative aging effects on the carbon nanotube (CNT)-asphalt nanocomposite interface has long been a challenge, as there are two opposing effects: enhancement and deterioration. In this study, a multiscale coupling method is proposed to analyze the dual effect of oxidative aging on the CNT-asphalt nanocomposite. The method is based on density functional theory (DFT) and molecular dynamics (MD) simulations, supported by microscopic interface observation and macroscopic property testing with a focus on the composite interface. The results show that oxidative aging has a resetting effect on benzene ring stacking at the interface and enhances the binding energy of CNT-asphalt. Meanwhile, oxidative aging enhanced the interfacial charge transfer, but no chemical reaction occurred between CNT-aged asphalt. This is also verified by Fourier Transform Infrared Spectroscopy (FTIR). Enhancement and degeneration effects of oxidative aging occur via distinct mechanisms. Oxidative aging enhanced the interfacial shear barrier by approximately 5% and the energy barrier by 44.87%, which increased the high-temperature deformation resistance of the CNT-asphalt nanocomposites. However, molecular oxidation was not responsible for the decline in the fatigue resistance. According to scanning electron microscopy (SEM) and atomic force microscopy (AFM) results, oxidative aging elevates the content of polar molecules, leading to an increase in the solid properties of asphalt and a 39.6% decrease in surface adhesion. This disrupts the three-dimensional network of the CNT and ultimately leads to a reduction in crack resistance. This study clarifies the mechanism underlying the dual effect of oxidative aging and provides fundamental support for understanding asphalt aging behavior and the interfacial behavior of composites.

Cellulose fiber-enabled mitigation of polysulfide shuttling and dendritic lithium growth in lithium–sulfur batteries

Decarbonization demands more batteries. Lithium-sulfur (Li–S) batteries are considered one of the most promising next-generation “post-Li-ion” batteries, whose practical viability is still hindered by two major challenges, polysulfide shuttling and dendritic lithium growth. Coating cellulose fibers onto separators has been proven to be an effective route for solving the two challenges simultaneously. Studying the working mechanism of the cellulose fiber is important yet difficult when the battery is in operation. Here, density functional theory and molecular dynamic simulations unveiled atomistically how cellulose fiber impedes polysulfides and lithium ions passing through the fiber, mitigating polysulfide shuttling and retarding dendritic lithium growth. This cost-effective modification paves the way towards more viable, sustainable Li–S batteries.

In Situ Polymerization of Methylene Blue on Bacterial Cellulose for Photodynamic/Photoelectricity Synergistic Inhibition of Bacterial Biofilm Formation.

In the context of long-term antimicrobial treatment, the emergence of bacterial resistance poses a significant challenge. Therefore, there is a pressing need to develop novel antimicrobial materials and methods that can effectively and safely combat microbial infections. This study focuses on the synthesis of bacterial cellulose-polymethylene blue (BC-PMB) with integrated photodynamic and photoelectric antimicrobial properties. The polymerization of methyl blue (MB) onto bacterial celluloses (BC) was achieved, and through comprehensive computational analyses using density functional theory (DFT) and molecular dynamics simulations, it was confirmed that this polymerization greatly enhanced the binding efficiency between methylene blue and BC. Additionally, polymethylene blue (PMB) exhibited superior photoexcitation efficiency and conductivity compared to its precursor. When BC-PMB was exposed to a 30 mW 660 nm light source for 30 min, the material demonstrated a remarkable antimicrobial efficacy of 93.99% against Escherichia coli and 98.58% against Staphylococcus aureus. Furthermore, the synergistic effect of photodynamic and photoelectric antimicrobial mechanisms exhibited long-term inhibitory capabilities against bacterial biofilms.

Photo-Programmable Processes in Bithiophene–Azobenzene Monolayers on Gold Probed via Simulations

In this study, we investigate the structural changes, electronic properties, and charge redistribution within azo-bithiophene (Azo-BT)-chemisorbed monolayers under different light stimuli using the density functional theory and molecular dynamics simulations. We consider two types of switches, Azo-BT and BT-Azo, with different arrangements of the Azo and BT blocks counting from the anchor thiol group. The chemisorbed monolayers of pure cis- and trans-isomers with a surface concentration of approximately 2.7 molecules per nm2 are modeled on a gold surface using the classical all-atom molecular dynamics. Our results reveal a significant shrinkage of the BT-Azo layer under UV illumination, whereas the thicknesses of the Azo-BT layer remain comparable for both isomers. This difference in behavior is attributed to the ordering of the trans-molecules in the layers, which is more pronounced for Azo-BT, leading to a narrow distribution of the inclination angle to the gold surface. Conversely, both layers consisting of cis-switches exhibit disorder, resulting in similar brush heights. To study charge transfer within the immobilized layers, we analyze each snapshot of the layer and calculate the mean charge transfer integrals using Nelsen’s algorithm for a number of interacting neighboring molecules. Combining these integrals with reorganization energies defined for the isolated molecules, we evaluate the charge transfer rates and mobilities for electron and hole hopping within the layers at room temperature based on Marcus’ theory. This research offers new perspectives for the innovative design of electrode surface modifications and provides insights into controlling charge transfer within immobilized layers using light triggers. Additionally, we identify molecular properties that are enhanced via specific molecular design, which contributes to the development of more efficient molecular switches for various electronic applications.

Constructing Efficient Mg(CF3SO3)2 Electrolyte via Tailoring Solvation and Interface Chemistry for High‐Performance Rechargeable Magnesium Batteries

AbstractNon‐passivating and chlorine‐free electrolytes are crucial for making rechargeable magnesium batteries practically feasible. Rational design of a brand‐new electrolyte should balance both Mg salt and solvent considering that the interfacial reactions occurring at electrolyte/electrode interface involve with ion solvation structure. Herein, nitrogenous 2‐methoxyethylamine (MOEA) is employed as co‐solvent to regulate the coordination behavior of cations/anions in Mg(CF3SO3)2‐G2 electrolyte after a series of screenings, which enables significantly ameliorated physiochemical properties. In‐depth insight on the mechanism of MOEA participating in the solvation structure formation and interfacial reactions is deduced via density functional theory calculations and molecular dynamics simulations. The decompositions of MOEA‐tailored cationic/anionic complexes shield Mg anode and Mo6S8 cathode with Mg3N2 and CxNy‐rich layers, respectively, which enable to suppress side reaction and accelerate Mg2+ transportation with competing desolvation at the interfacial layer. All the merits endow remarkable performances of symmetric/asymmetric cells with ultralong‐cycle lives over 5000 h and a remarkable average Coulombic efficiency of 98.3% after 8200 cycles (≈11 months), respectively. Additionally, a cheerful discharge capacity of ≈59.3 mAh g−1 is obtained over 1000 cycles at 0.5 C in Mo6S8||Mg full cell.

A computational investigation on the roles of binding affinity and pore size on CO2/N2 overall adsorption process performance of MOFs through modifying MIL-101 structure

To develop an appropriate metal-organic framework to capture CO2 from dry flue gas, understanding the roles of structural modifications, location of primary adsorption sites and underlying adsorption mechanisms is crucial. Herein, effects of type, position and concentration of nitrogen-containing functional groups and C/N-substituted ligands are investigated on overall CO2/N2 adsorption process performance and mechanism of pristine and metal-substituted MIL-101 MOFs. In this investigation, density functional theory computations, grand-canonical Monte-Carlo, and molecular dynamics simulations are applied. Taguchi-based overall evaluation criteria objective function is also used to assess the overall adsorption performances of these MIL-101 MOFs in terms of CO2 uptake capacity, CO2/N2 selectivity, isosteric heat of adsorption and mass transfer resistance. The PBE/DZVP computations resulted in the CO2-framework binding energies ranging from −3.85 to −21.01 kJ/mol implying an acid-base type of physisorption. A correlation is introduced to estimate the CO2 uptake capacity from binding affinity and pore diameter of these MIL-101 MOFs. Mechanistic investigations show that to enhance CO2 uptake capacity and CO2/N2 selectivity, functionalization of the linker ligands is more successful than functionalization of the open metal sites having strong interactions with CO2 molecules. Results also showed that the best possible scenario to improve the overall adsorption process performance of MIL-101 is to substitute the C atom(s) of the BDC ligands with the N atom(s), regardless of the central metal atom type. The comprehensive molecular design approach introduced in this work can be used as a methodology by scientists for the development of new MOFs for practical CO2 capture applications.

Corrosion inhibition of brass electrode in 3% NaCl medium using novel quinoline derivatives based on D-glucose: Synthesis, characterization, and mechanistic insights through experimental and computational approaches

Two novel quinoline derivatives, namely P1 and P2, were successfully synthesized using D-Glucose as a starting material. The synthesized compounds were subjected to characterization using carbon-13 nuclear magnetic resonance (13C NMR) and proton nuclear magnetic resonance (1H NMR) spectroscopy techniques. Their anticorrosive properties for brass electrode in 3% NaCl medium were evaluated by different physicochemical and electrochemical characterization techniques. Further, reactivity and interaction mechanisms between P1 or P2andthe first zinc (Zn) and copper (Cu) layer atoms present in the brass surface were studied by the density functional theory (DFT) calculations and molecular dynamic (MD) simulations. The electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves (PC) indicated that P1 and P2acted as barrier of the anticorrosive of brass area and its inhibition efficiencies reaches a maximum of 96.9 and 97.2% for P1 and P2 at optimal concentration, respectively. The adsorption of P1 and P2 onto the brass surface followed the Langmuir adsorption isotherms, indicating monolayer adsorption. Additionally, the adsorption process was characterized as chemisorption, suggesting a strong chemical interaction between the compounds and the metal surface. SEM/EDS analysis indicated a significant difference in brass area in the presence of 10−3M of P1 and P2 due to the formation of a layer protective barrier. Finally, the corrosion inhibition mechanism was explored and comprehended through the integration of experimental data and computational approaches.

Synthesis, Characterization, Density Functional Theory, Monte Carlo, and Molecular Dynamics Simulations of [Ni(Ii)(Tpy)2] Metal Organic Framework and Congo Red Dye Application

Effluents from dyeing companies are a major polluter of the environment and water bodies. An estimated 70 tons of dye are generated globally each year, with more than one-third of this amount lost to the environment. To combat this issue, novel chemical compounds that are more efficient than existing ones are proposed. The soft synthetic approach was used to create [Ni(II)(Tpy)2] MOF by reacting nickel nitrate with terpyridine (Tpy). The melting point of the MOF was determined, as well as the EA, HSM, TGA, PXRD, and X-ray crystallographic studies. The MOF results support the synthesis and coordination of the nickel (II) ion with the two Tpy molecules. In application, [Ni(II)(Tpy)2] MOF was utilized to study the adsorption of Congo red. After 30 min of adsorption time, 1 g of [Ni(II)(Tpy)2] MOF adsorbed a high amount of Congo red (138.26 mg) at [Formula: see text]C and a pH of 2. When compared to other isotherms, the Langmuir isotherm provided the best fit. Adsorption kinetics demonstrating electrostatic interaction between MOF and Congo red might be interpreted using the pseudo-second-order model. Density functional theory, Monte Carlo, and molecular dynamics simulations of the [Ni(II)(Tpy)2] MOF over Congo red dye were computed. Density functional theory calculations provide insights into the reactivity of the novel [Ni(II)(Tpy)2] MOF by furnishing chemical reactivity parameters that explain the interactions and adsorption processes between the [Ni(II)(Tpy)2] MOF and Congo red. The quantum mechanical calculations provide data for an insightful understanding of the reactivity of the MOF and its high adsorption on the Congo red surface. Low band gaps (1.40 and 1.43 eV in the gas phase and water, respectively) obtained for the [Ni(II)(Tpy)2] MOF suggest that this will make an extrinsic semiconductor with high electrical conductivity. Thus, it would readily interact with and be adsorbed on the Congo red.

Structural, electronic and mechanical properties of double core carbon nanothreads

The synthesis of double core carbon nanothreads (NTHs) has been recently achieved through compression of aromatic molecules containing two rings connected by short chains featuring either double or triple bonds (such as stilbene, azobenzene and diphenylacetylene). Their structure are characterized by two conventional 1D NTHs cores, interconnected by covalent bonds arranged in several ways. In this paper, we provide a comprehensive analysis of the possible atomic structures for double core NTHs, evaluate their relative stability, and calculate some electronic and mechanical properties, using Density Functional Theory calculations and Molecular Dynamics simulations. Many isomers are possible for these 1D materials, differing by the intrinsic structure of the cores and the nature of the covalent bonds crosslinking them. For stilbene and diphenylacetylene NTHs, the most stable isomers feature continuous sp3 or sp2 C-C chains connecting the cores, while those that preserve the original unsaturation of the molecule (azo group) are the most stable for azobenzene. The mechanical behavior of these NTHs are similar to that of conventional single core ones, with enhanced 1D strength and stiffness when continuous chains connect the cores. Their electronic behavior range from metallic to insulating depending on the arrangement of the bonds connecting the cores, and the materials with the narrowest band gaps feature electron delocalization along the chain connecting the cores. The variations in properties associated to the presence of bonds connecting the cores bring new opportunities to the design of electronic and optical devices employing this class of strong and flexible materials.

Automated potential development workflow: Application to BaZrO3

We present a Python workflow, Automated Potential Development (APD), for automating the development of interatomic potentials, including calculation of density functional theory (DFT) fitting data, optimization of potentials, and potential-driven molecular dynamics (MD) simulations. The workflow currently supports CASTEP and VASP DFT codes and the MEAMfit potential optimization code for optimization of reference-free modified embedded atom method (RF-MEAM) potentials. The LAMMPS software is supported for calculating the relaxed geometry, elastic constants, phonon dispersion, thermal expansion and radial distribution functions using the optimized potentials. These same properties are also computed at the DFT level and APD automatically generates plots and tables of these data. Query-by-committee active learning is supported, using multiple fitted potentials to evaluate the energies of atomic configurations generated from LAMMPS MD runs. The workflow is demonstrated on BaZrO3, an oxide-based perovskite material, with RF-MEAM results found in good agreement with DFT. Program summaryProgram title: Automated potential development (APD) workflowCPC Library link to program files:https://doi.org/10.17632/pd9gbxyy8d.1Developer's repository link:https://gitlab.com/AndyDuff123/meamfitLicensing provisions: BSD 3-clauseProgramming language: Python, BashNature of problem: Development of new interatomic potentials is a time-consuming process and requires expertise in density functional theory (DFT), potential optimization, and molecular dynamics (and statics) simulations using the optimized potential. Furthermore repeated cycles are usually required to fix numerical issues and improve the potential, requiring further DFT calculations and potential reoptimization. There are also many tedious steps including setting up inputs, submitting jobs (including continuation jobs where jobs terminated prematurely), analyzing outputs, and validating predictions of the interatomic potential. The latter requires multiple calculations of properties computed at both the DFT and potential level.Solution method: The APD workflow provides a black-box solution to fully automate the generation of interatomic potentials. The workflow takes as input a Materials Project id and temperature range of interest. All DFT, potential optimization, and potential molecular dynamics simulations are automatically set-up, submitted and analyzed. Active-learning is incorporated, and properties are computed both at the DFT and potential-level for validation purposes, with tables and graphs for relaxed geometry, elastic constants, phonon dispersion, partial radial distribution functions, and thermal expansion automatically generated.Additional comments including restrictions and unusual features: A full guide to installation, including setting up an environment with all relevant packages and libraries, are included in the distribution. The APD workflow is currently restricted to RF-MEAM potentials and the properties listed above. Some materials which are particularly challenging at the DFT level, e.g. complex magnetic structures, may require intervention in tuning DFT input parameters.

Assessment of New Imidazol Derivatives and Investigation of Their Corrosion-Reducing Characteristics for Carbon Steel in HCl Acid Solution

This study assessed the corrosion inhibitory and adsorption properties of two imidazol derivatives, namely 5-((2,4,5-triphenyl-1H-imidazol-1-yl)methyl)quinolin-8-ol (TIMQ) and 5-((2-(4-chlorophenyl)-4,5-diphenyl-1H-imidazol-1-yl)methyl)quinolin-8-ol (CDIQ), on carbon steel (CS) in 1 M of HCl using electrochemical methods, including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization measurements (PDP), UV–visible spectroscopy (UV–v), scanning electron microscopy (SEM), and molecular modeling. The findings showed that TIMQ and CDIQ were potent inhibitors with inhibition efficiencies of 94.8% and 95.8%, respectively. The potentiodynamic polarization experiments showed that the inhibitors worked as mixed-type inhibitors, and the impedance investigations supported the improvement of a protective layer for the inhibitor on the metal surface. Each inhibitor was adsorbed onto the carbon steel surfaces, according to the Langmuir adsorption method. The steel was shielded from acidic ions by an adsorbed coating of the inhibitor molecules, according to SEM. Density functional theory (DFT) calculations and molecular dynamics (MD) simulations were used to inspect the results, and a good correlation was found between these results and those of the study. This information can be applied to determine the effectiveness of inhibitors in a HCl acid solution.

Structural Expansion of Cyclohepta[def]fluorene towards Azulene-Embedded Non-Benzenoid Nanographenes.

Non-benzenoid non-alternant nanographenes (NGs) have attracted increasing attention on account of their distinct electronic and structural features in comparison to their isomeric benzenoid counterparts. In this work, we present a series of unprecedented azulene-embedded NGs on Au(111) during the attempted synthesis of cyclohepta[def]fluorene-based high-spin non-Kekulé structure. Comprehensive scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM) evidence the structures and conformations of these unexpected products. The dynamics of the precursor bearing 9-(2,6-dimethylphenyl)anthracene and dihydro-dibenzo-cyclohepta[def]fluorene units and its reaction products on the surface are analyzed by density functional theory (DFT) and molecular dynamics (MD) simulations. Our study sheds light on the fundamental understanding of precursor design for the fabrication of π-extended non-benzenoid NGs on a metal surface.

First-principles calculations of the solvent effects on magnesium polysulfides in magnesium-sulfur batteries

Magnesium-sulfur (Mg-S) batteries have gained much attention in research community of rechargeable magnesium batteries (RMBs) due to the high energy density, safety, and low cost. The main challenge in the development of practical Mg-S batteries is the dissolution of intermediate magnesium polysulfides (Mg-PSs) in the electrolyte and their migration to the Mg anode, which results in the notorious shuttle effect. In this study, we combine static density functional theory (DFT) calculations and molecular dynamics (MD) simulations to explore the solvated structures of Mg-PSs with different solvents (THF, DOL and DME) and the reduction processes of solvated Mg-PSs, and the diffusion of S8 for the first time, helping to address the challenges of developing novel electrolytes for Mg-S batteries. Our results demonstrate the effect of solvents on the electrochemical reactions of S cathode in Mg-S batteries and could contribute to the advancement of efficient and high-energy Mg-S batteries.

Gradient fluorinated and hierarchical selective adsorption coating for Zn-Based aqueous battery

Rechargeable aqueous zinc-ion batteries (ZIBs) are considered as one of the most promising large-scale energy storage system due to their high energy density, low cost and inherent safety. However, the notorious dendrite growth and severe side reactions, impede their practical application. Herein, we constructed a multifunctional gradient composite fluorinated coating with insulating ZnF2 outside and Zn/Sn alloy inside. ZnF2 outside and Zn/Sn alloy inside perform their own functions and solve the dendrites and side reactions jointly. Density functional theory (DFT) calculations and Molecular dynamics (MD) simulations demonstrate that the electronically insulating ZnF2 layer on the surface can regulate the transport of Zn2+ cations, limit the free H2O molecules and improve the dissolution of Zn2+, at the same time, the zincophilicity Zn/Sn alloy inside work as the favorable nucleation sites for Zn atoms and lowers the Zn2+ diffusion energy barrier. As a result, the ZnF2-Sn@Zn electrode in a symmetrical cell exhibits a long cycle life of about 1400 h, as well as 91 % capacity retention after 1400 cycles at 1 A/g in the ZnF2-Sn@Zn//MnO2@CNT full batteries. This work provides a practically promising strategy and new insights for the electrolyte and anode interface design.

Investigate the ability of deep eutectic solvent (ChCl-glycerol) to sense the sulphur dioxide using density functional theory calculations and molecular dynamics simulations

SO2 gas is one of the major industrial pollutants, by-product obtained from the combustion of fossil fuels, is an indirect greenhouse gas. Hence, deep eutectic solvent can offer an inexpensive and efficient way for its sensing and removal. A theoretical investigation for deep eutectic solvent (DES) consisted of choline chloride and glycerol has been done with density function theory (DFT) calculations. DES was investigated for adsorption of SO2. Herein, feasibility of adsorption ability of the DES for different concentration or amount of SO2 was performed; on varying the ratio of DES: SO2 from 1:1 to 1:4. The change in feasibility of interaction of the DES and SO2 was also studied with the change in temperature using DFT computation. The study was done by analyzing the interactions, thermodynamic properties obtained from DFT calculations. The stability & interaction between DES and SO2 as well as the extent of charge transfer was analyzed with the help of natural bond orbital (NBO) analysis and density of states spectra (DOS). Molecular dynamic (MD) simulations of the DES and DES:SO2 (1:1 to 1:4) were performed and the interactions were analyzed using root mean square deviation (RMSD), root mean square fluctuation (RMSF) and radial distribution function (RDF). It was observed that the DES exhibited most stable interactions in the gaseous state. DES in gaseous state exhibited very stable interaction with the SO2 molecule as the concentration of the SO2 was increased the stability of interaction was also observed to increase. With the increase in temperature, the feasibility of interaction between DES and SO2 decreases.

Screening Platform for Promising Na Superionic Conductors for Na-Ion Solid-State Electrolytes.

Na-ion batteries are considered a promising alternative to the analogous Li-ion batteries because of their low manufacturing cost, large abundance, and similar chemical/electrochemical properties. In particular, research on Na-ion solid electrolytes, which resolve the flammability issues associated with liquid electrolytes and increase the energy density obtained using a particular metal anode, is rapidly growing. However, the ionic conductivities of these materials are lower than those of liquids. We present a novel classification approach based on machine learning for identifying Na superionic conductor (NASICON) materials with outstanding ionic conductivities. We obtained new features based on chemical descriptors such as Na content, elemental radii, and electronegativity. We then classified 3573 NASICON structures by implementing the ensemble model of gradient boosting algorithms, with an average prediction accuracy of 84.2%. We further validated the thermodynamic stability and ionic conductivity values of the materials classified as superionic materials by employing density functional theory calculations and ab initio molecular dynamics simulations. Na3YTaSi2PO12, Na3HfZrSi2PO12, Na3LaTaSi2PO12, and Na3ScTaSi2PO12 were confirmed as promising NASICON structures that fulfill the requirements of solid-state electrolytes.