Bulk Properties Research Articles

Computer-Aided formulation design for pharmaceutical drug product development, part 01: Materials exploration through a visualization tool

An interactive tool has been developed to help design oral solid dosage form formulations. The tool enables quantitative explorations and comparisons of physical, bulk, and mechanical properties, and takes into account functional characteristics as well. In this manner, comparisons and clustering of both excipients and APIs can be carried out. These comparisons enable the generation of alternatives as well as surrogate identification, so as to spare resources and material.Multiple data sources were merged to create a “joint” data table with all relevant properties. Four main workflow activities are supported: Explore Materials, Search Similar APIs, Search Similar Excipients and Search Material Clusters.Multi-dimensional filtering can be superimposed to each functionality. Suggested visualizations are made particularly accessible by providing them as “standard plots”.The underlying philosophy is to empower formulation scientists to explore options, rather than prescribe decisions on exclusively mathematical grounds. The tool described here is the first step towards a holistic optimization incorporating predictions of mixture properties. Methodology of use is illustrated through three material selection application examples.

Predicting the diffusion coefficients of rejuvenators into bitumens using molecular dynamics, machine learning, and force field atom types

This study explores the use of chemical descriptors derived from force field atom types to predict Fickian diffusion coefficients of rejuvenators in bitumen, utilizing machine learning models trained on data from 240 non-equilibrium molecular dynamics simulations. The simulations cover three bitumen types (NO, TO, FO), five aging degrees, and four temperatures (60 °C, 120 °C, 160 °C, 200 °C), capturing diffusion coefficients ranging from 0.0068e-10 m2/s in highly aged bitumens at 60 °C to 4.35e-10 m2/s in fresher samples at 200 °C. The MLM, built with 18 chemical descriptors for bitumen and rejuvenator sides, achieves an R2 of 0.97, accurately predicting diffusion across varied conditions. This approach abstracts away from the need for repeated MD simulations, enabling diffusion predictions even for systems outside the original dataset. The manuscript presents three case studies to illustrate how the model can be used for the iterative design of rejuvenators by optimizing molecular structures based on critical chemical features, such as rejuvenator oxygen content, bitumen sulfur content, and molecular weights. It also demonstrates how the model offers a practical framework for understanding the diffusion and performance of rejuvenators by linking time-dependent factors—such as concentration, depth, and rejuvenation time—with the bulk properties of bitumen-rejuvenator systems, facilitating industrial applications

Hydrocarbon potential, source correlation, and paleoenvironmental reconstruction of the Jurassic interval in the Zey Gawra Oilfield, Kurdistan Region, Iraq

A comprehensive geochemical analysis for the Sargelu, Naokelekan, and Najmah formations cutting rock and crude oil samples from Z1, Z3, and Z5 wells of Hawler Block, Kurdistan Region, Iraq have been studied for source rock evaluation. Depending on the total organic carbon (TOC) content from pyrolysis analyses, the Sargelu and Naokelekan formations are regarded as very good source rocks, and fair source rock for the Najmah Formation. The organic matter in the Sargelu Formation is characterized by types II and mixed II and III kerogens. However, the Naokelekan and Najmah formations are characterized by type II kerogen. The Sargelu and Naokelekan formations’ organic matters are at mature stages; hence, in the oil window, whereas Najmah Formation’s organic matter is at immature stage. Pyrolysis study shows that the Sargelu Formation is oil and gas prone, while the Najmah and Naokelekan formations are oil prone. The biomarkers and bulk properties of the selected oils from Gas Chromatography (GC) and Gas Chromatography-Mass Spectroscopy (GC/MS) analysis show that they originated by the same source rocks. The geochemical characteristics indicate a carbonate source in a reducing environment for the studied formations and oils. Based on the oleanane index, tricyclic terpane indices, C28S/C29S ratios, and gammacerane index, the relative age of the oils and cuttings of Sargelu, Naokelekan, and Najmah formations is Middle to Late Jurassic and deposited under moderate saline condition. The biomarkers parameters show evidence that molecules from the cutting rocks of the Sargelu and Naokelekan formations are related to the oils in Z1, Z3, and Z5 wells. However, they are not related to the Najmah Formation.

Revealing subterahertz atomic vibrations in quantum paraelectrics by surface-sensitive spintronic terahertz spectroscopy.

Understanding surface collective dynamics in quantum materials is crucial for advancing quantum technologies. For example, surface phonon modes in quantum paraelectrics are thought to be essential in facilitating interfacial superconductivity. However, detecting these modes, especially below 1 terahertz, is challenging because of limited sampling volumes and the need for high spectroscopic resolution. Here, we report surface soft transverse optical (TO1) phonon dynamics in KTaO3 and SrTiO3 by surface-sensitive spintronic terahertz spectroscopy that can sense the collective modes only a few nanometers deep from the surface. In KTaO3, the TO1 mode softens and sharpens with decreasing temperature, leveling off at 0.7 terahertz. In contrast, this mode in SrTiO3 broadens substantially below the quantum paraelectric crossover and coincides with the hardening of a sub-milli-electron volt phonon mode related to the antiferrodistortive transition. These observations that deviate from their bulk properties may have implications for interfacial superconductivity and ferroelectricity. The developed technique opens opportunities for sensing low-energy surface collective excitations.

Effect of carbon ion implantation on the superconducting properties of MgB2 bulks prepared by powder-in-sealed-tube method

We studied the effect of carbon (C) ion implantation on the microstructure and superconducting properties of bulk MgB2 prepared by the powder-in-sealed-tube (PIST) method. FESEM and TEM analysis indicate microstructural changes due to carbon ion implantation. DC magnetization measurements reveal a slight improvement of TC and small ΔTC values due to ion implantation. The JC(B) characteristics of implanted samples show a significant enhancement of JC compared with pristine MgB2 at 10 and 20 K. MgB2 samples implanted with 80 keV carbon ions with a dose of 2 × 1016 ions cm−2 show maximum enhancement in JC i.e., 2.07 × 105 A/cm2 at 5 T and 10 K. The flux pinning force density curves are theoretically analyzed using the Dew-Hughes model. The results reveal that significant enhancements in the flux pinning properties are contributed by the normal point defects caused by carbon ion implantation, which acts as a strong pinning center.

Au@TiO2 Core-Shell Nanoparticles with Nanometer-Controlled Shell Thickness for Balancing Stability and Field Enhancement in Plasmon-Enhanced Photocatalysis.

Plasmonic core-shell nanostructures can make photocatalysis more efficient for several reasons. The shell imparts stability to the nanoparticles, light absorption is expanded, and electron-hole pairs can be separated more effectively, thus reducing recombination losses. The synthesis of metal@TiO2 core-shell nanoparticles with nanometer control over the shell thickness and understanding its effect on the resulting photocatalytic efficiency still remains challenging. In the present study, a synthesis method is presented for preparing Au@TiO2 core-shell nanoparticles with ultrathin shells that can be accurately tuned in the range of 2-12 nm, based on the controlled slow hydrolysis of a titanium precursor. Electromagnetic simulations combined with comprehensive characterization of the opto-physical bulk properties, as well as energy electron loss spectroscopy and electron tomography reconstructions at the nanoscale, aid in understanding the crucial role of the shell in improving both the activity as well as the stability in a photocatalytic reaction. Ultrathin shells in the order of 2 nm do not suffice to prevent sintering of the nanoparticles upon annealing, with a consequent loss of plasmonic properties. After reaching an optimum for a shell of 4 nm, further increasing the shell thickness again reduces the plasmonic properties by a weakened plasmonic coupling. This trend is confirmed by photocatalytic hydrogen evolution experiments, as well as stearic acid degradation tests. With this study, we prove and emphasize the crucial importance of carefully controlling the shell thickness in plasmonic core-shell structures, so their maximum application potential may be unlocked.

Interfacial and Bulk Properties of Potato and Faba Protein in Connection with Physical Emulsion Stability at Various pH Values and High Salt Concentrations.

The protein transition motivates the use of plant proteins, but their application in food emulsions is challenging, especially when high concentrations of oil and salt are needed for formulation and sensory properties. In the present work, we connect the iso-electric point of two potato protein isolates (patatin-rich, POPI-200; protease inhibitor-rich, POPI-300) and a faba protein isolate (FPI) to the behavior in the bulk phase and at the interface, and relate this to the physical stability of 45 wt% oil-in-water (O/W) emulsions in the presence of NaCl at pH 4.0-7.0. In the absence of NaCl, a higher bulk viscosity was found at the iso-electric point (IEP), especially for the FPI. In the presence of NaCl, the viscosity of the POPI-200 solutions was highest, followed by POPI-300, and that of the FPI was lowest, irrespective of the pH. Both POPIs showed faster initial adsorption at the O/W interface in the absence of NaCl, and formed a more elastic layer compared to the FPI. For all proteins, salt addition leads to less elastic films. Interestingly, the interfaces were more elastic at a pH close to the IEP of the protein in the presence of NaCl. Both POPI-stabilized emulsions showed higher stability (smaller size and less oiling off) than the FPI-stabilized emulsions, which makes potato proteins relevant for food emulsion product formulation, even under high salt conditions.

Thermodynamic properties of pinned nanobubbles.

We present molecular dynamics simulations to study the thermodynamics of nanobubbles trapped at the mouth of narrow slit pores. Except when the slit dimensions are comparable to typical molecular sizes, the predictions of macroscopic thermodynamic theory are recovered by our simulations. Our simulations confirm that in this case, the internal pressure of stable nanobubbles is independent of the bubble radius and the surface tension and only depends on the bulk properties of the solute-containing solution, i.e., the chemical potential balance. However, in the case of extreme confinement, the pressure is not a suitable quantity to describe the thermodynamics of the bubbles, while the balance of the chemical potentials is.

Equality of Magnetization and Edge Current for Interacting Lattice Fermions at Positive Temperature

We prove that the magnetization is equal to the edge current in the thermodynamic limit for a large class of models of lattice fermions with finite-range interactions satisfying local indistinguishability of the Gibbs state, a condition known to hold for sufficiently high temperatures. Our result implies that edge currents in such systems are determined by bulk properties and are therefore stable against large perturbations near the boundaries. Moreover, the equality persists also after taking the derivative with respect to the chemical potential. We show that this form of bulk-edge correspondence is essentially a consequence of homogeneity in the bulk and locality of the Gibbs state. An important intermediate result is a new version of Bloch’s theorem for two-dimensional systems, stating that persistent currents vanish in the bulk.

On the Parasitic Surface Adsorption of Pyrrolidinium and Phosphonium-Based Ionic Liquid Preventing Accurate Differential Capacitance Measurements

Ionic Liquids (ILs) have received a substantial interest from the scientific community over the past few decades1, in particular, because of their possible use as electrolytes for battery technology. This wide excitement stems from their known thermal stability and non-volatile nature2 (as opposed to more traditional organic carbonate-based electrolytes) which has led the study of IL to fall under the category of green chemistry3.In a similar fashion to aqueous-based electrolytes, whose bulk properties are fundamentally different from their properties near charged interfaces (giving rise to an Electrical Double Layer, EDL), ILs and IL-based electrolytes also exhibit a distinct interfacial structuring near charged surfaces consisting of alternating layers of cations and anions4 extending into the liquid over several nanometers5. This interfacial structuring (i.e., EDL) initially formed at the electrode/electrolyte interface defines the charge transfer mechanism6. It is also believed to play a critical role in the formation of the Solid Electrolyte Interphase (SEI)7,8. The latter, via its morphological, mechanical and chemical properties directly governs the performance of the battery9.Electrochemical Impedance Spectroscopy (EIS) is an attractive technique for the indirect study of the EDL at charged interfaces, via the so-called differential capacitance measurement. The latter giving an indication of the ionic density near the interface10. Differential capacitance measurements are, however, difficult to interpret and compare, because there is no real consensus as to how the measurement needs to be performed. To add to the difficulty, some ionic liquids are known to display a hysteresis process, inducing measurement variabilities.In this study, we propose to investigate the structure of the EDL of pure IL (trimethyl isobutyl phosphonium bis(fluorosulfonyl)imide, P111i4FSI and N-methyl-N-propylpyrrolidinium bis(fluorosulfonyl)imide, C3mpyrFSI) as well as IL-based electrolytes composed of 42mol% of NaFSI in C3mpyrFSI and/or P111i4FSI using both a differential capacitance and AFM approach. Using a well-established method for the measurement of the differential capacitance in IL and IL-based electrolytes, we show that all the studied systems display important hysteresis properties (in particular, the pyrrolidinium-based ones). Via a series of differential capacitance as well as AFM experiments, we further demonstrate that the hysteresis is a result of adsorption processes on the surface of the electrode. This parasitic adsorption leads inaccuracies in traditional differential capacitance measurements. We therefore propose an alternative method for the measurement of the differential capacitance which allows to minimize the impact of adsorption.This new understanding of differential capacitance measurements has important methodological implications. By providing guidelines for accurately probing the differential capacitance of ILs and IL-based electrolytes, in particular, pyrrolidinium and phosphonium-based ones via a single, reliable method, this report may well help pave the way to easier comparisons and interpretations. J.P. Hallett et al., Chem. Rev. 2011, 111, 3508-3576.S. Zhang et al., ACS Appl. Mater. Interfaces 2021, 13, 53904-53914.K. Paduszynski et al., J. Chem. Inf. Model. 2014, 54, 1311-1324.J.M. Black et al., ACS Appl. Mater. Interfaces 2017, 9, 40949-40958.R. Hayes et al., Chem. Rev. 2015, 115, 6357-6426.D. Rakov et al., Chem. Mater. 2021, 34, 165-177.Q. Wu et al., J. Am. Chem. Soc. 2023, 145, 2473-2484.D.S. Silvester et al., J. Phys. Chem. C 2021, 125, 13707-13720.Y. Zhou et al., Nat. Nanotechnol. 2020, 15, 224-230.J.M. Klein et al., Phys. Chem. Chem. Phys. 2019, 21, 3712-3720. Figure 1

Preparation of Low Melting Temperature Lithium-Based Binary Salts and Their Physicochemical Properties

Achieving carbon neutrality demands the development of high-performance Li-ion secondary batteries (LIB), driven by a pressing need for electric vehicles and renewable energy storage. Molten salt electrolytes offer promise for enhancing safety and performance due to their exceptional thermal stability and high Li+ transport numbers(1). However, the high operating temperature range of molten salts, stemming from high melting temperatures, presents a significant challenge. In this study, we propose Li salts with low melting points achieved through increased entropy and eutectic effects by mixing multi-Li salts. Our focus lies on the anion structure of fluorosulfonyl compounds, aiming to create salts with low melting points. Through mixing of an asymmetric anion salt (Li[N(SO2 CF3)(SO2F)], LiFTA) and versatile Li salts (Li[N(SO2F)2], LiFSA and Li[N(SO2CF3)2)], LiTFSA) we identified compositions with melting points lower than those of individual salts. We investigated the preparation scheme of the salt mixtures, their bulk properties, and electrochemical characteristics.Preparation of mixed salts was conducted in an Ar-filled glove box. Two salts from LiFTA, LiFSA, and LiTFSA were mixed in prescribed molar ratios, dissolved in acetonitrile (AN), and removed AN by heating at 373 K~413 K. The absence of residual AN in the Li mixed salt was confirmed through thermogravimetry (TG-DTA) and differential scanning calorimetry (DSC). The thermal properties of mixed salts were evaluated using TG-DTA and DSC. Ionic conductivity (σ) of the mixed Li salts was measured from 403 K to 263 K, with an alternating current (AC) amplitude of 500 mV over a frequency range of 500 kHz to 50 mHz.For low melting point LiFTA (T m = 376 K), pulsed-field gradient NMR (PFG-NMR) was obtained to measure self-diffusion coefficients (D) of each nucleus (Li+, FTA-) above T m (413 K~378 K). Compared to Li+, FTA- exhibited higher values of D, with activation energies of 74 kJ mol-1 for Li+ and 71 kJ mol-1 for FTA- (Figure 1). The difference in D between Li+ and FTA- suggests individual diffusion of the cation and anion. Figure 2 illustrates DSC profiles of each Li salt (LiFSA, LiTFSA) and mixed salts (LiFSA/LiTFSA). Mixing LiFSA and LiTFSA revealed a eutectic effect in the salt mixtures, particularly evident in the mixed salt Li([FSA]0.6[TFSA]0.4), which exhibited the lowest T m at 391 K. This melting point was lower than that of single salts, highlighting the effectiveness of mixing two versatile Li salts. Furthermore, highly amorphous nature was observed in Li([FSA]0.2[TFSA]0.8) through DSC analysis. The incorporation of LiFTA into the mixed salts (Li([FSA]0.6[TFSA]0.4)) holds promise for fabricating mixed salts with even lower T ms. Figure 3(a) displays DSC profiles of each Li salt (LiFTA, LiFSA) and mixed salts (LiFTA/LiFSA), while Figure 3(b) also depicts those of each Li salt (LiFTA, LiTFSA) and mixed salts (LiFTA/LiTFSA). The prepared mixed salts resulted in either transparent, highly viscous liquids or transparent to white solids. Mixed salts using LiFTA and LiTFSA became complete amorphous, indicating the potential for further reduction in melting points or the creation of supercooled Li ionic liquids.The Arrhenius plot of the ionic conductivity (σ) for Li([FSA]0.6[FTA]0.4) is presented in Figure 4. At 403 K, σ was rather low and 0.18 mS cm-1, which can be attributed to strong interactions between Li+ and the anion in the absence of solvents, resulting in high viscosity and reduced mobility. The conductivities exhibited close values between Li([FSA]0.6[FTA]0.4) and LiFTA. LiFTA showed a change from VFT to Arrhenius-type temperature dependence at 308 K, whereas Li([FSA]0.6[FTA]0.4) revealed stronger supercooling behavior compared to LiFTA.(1)Y. Yamada, A. Yamada, J. Electrochem. Soc., 162, A2406-A2423 (2015). Figure 1

Qualitative and Quantitative Proton Content Analysis of Chemically Delithiated Ni-Rich NCM Materials

The development of long-lasting, high-energy-density batteries is crucial for the electrification of multiple sectors. The current scope for cathode active materials (CAM) to meet this demand are the next-generation Ni-rich layered oxides Li(NixCoyMnz)O2 (x+y+z=1, x>0.8). However, understanding their aging and degradation mechanisms is essential for improving their long-term stability. Chemical delithiation can be used to obtain pure CAM powders (rather than electrodes) at various degrees of delithiation to better understand these mechanisms and to develop countermeasures to improve cycling stability.[1] However, during chemical delithiation, protons can intercalate into the structure of CAMs by ion exchange of Li+ with H+.[2,3] This potentially compromises the use of chemically delithiated CAM powders for mechanistic studies.Therefore, we investigated the amount of protons in the chemically delithiated materials and devised approaches to minimize the proton content. Quantifying the proton content presents unique challenges, for which we employed prompt gamma activation analysis (PGAA) for precise quantification. Based on this benchmark technique, we developed a more accessible method to quantify the proton content by correlating the gas release during heat treatment of the chemically delithiated materials to their weight loss. Furthermore, we analyzed the bulk and surface properties of a Ni-rich chemically delithiated NCM as well as its thermal decomposition in order to gain insights into the effects of chemical delithiation and its comparability to electrochemical delithiation. While the bulk remained intact and followed the expected lattice development upon delithiation,[4] chemically delithiated materials exhibited higher overpotentials during galvanostatic cycling, indicating a surface reconstruction which in electrochemical delithiation only occurs after a large number of charge/discharge cycles. Therefore, while chemical delithiation is a powerful tool to access characteristics not possible with electrochemical delithiation, it must be employed with the utmost care and consideration. Acknowledgment This work was financially supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy (EXC 2089/1 –390776260, e-conversion). The authors would like to thank BASF SE for providing the active materials used for this study. S Q. further acknowledges funding by the German Federal Ministry of Education and Research (BMBF) within the project Aqua-Pop (grant number 03XP0329B). References C. Tian, Y. Xu, D. Nordlund, F. Lin, J. Liu, Z. Sun, Y. Liu, and M. Doeff, Joule, 2, 464–477 (2018)S. Venkatraman and A. Manthiram, J Solid State Chem, 177, 4244–4250 (2004)J. Choi, E. Alvarez, T. A. Arunkumar, and A. Manthiram, ESL, 9, A241 (2006)F. Friedrich, B. Strehle, A. T. S. Freiberg, K. Kleiner, S. J. Day, C. Erk, M. Piana, and H. A. Gasteiger, J Electrochem Soc, 166, A3760–A3774 (2019)

Multiscale Materials and Process Engineering for Efficient CO2 Recycling

Renewable electricity powered conversion of carbon dioxide (CO2) to fuels and chemicals has potential to close the anthropogenic carbon cycle at meaningful scales and achieve global sustainability goals. It provides an effective route to store renewable energy in chemical bonds for its modular utilization in a circular carbon economy. However, the technological progress of this complex chemical transformation is stymied due to the lack of systematic materials design principles, poor understanding of the convoluted reaction pathways that control efficiency and selectivity, and complexities associated with elementary electron and mass transfer in the reaction environment. At a system level, issues of carbon and energy conversion efficiencies needs to be addressed. Engineering of materials and interfaces can have profound effects on the correlated bulk and surface physicochemical properties for judicious tuning of these parameters and reaction pathways. In my talk, I will present examples of our research to build a broad perspective on how the rational design of materials and processes can solve some key scientific/technological challenges in electron-driven CO2 recycling pathways through understanding of structure-activity correlations. On the materials aspect, engineering of low dimensional carbon and copper based systems will be discussed. Integration of electrochemical CO2 conversion with capture and alternative anodic oxidation reactions will be showcased to highlight emerging approaches in addressing technological challenges from a process perspective.

Electrolyte Descriptors for Current Efficiency and Stability for Lithium-Mediated Electrochemical Ammonia Synthesis

Ammonia (NH3) is a critical chemical that is used primarily as fertilizers (80%) as well as the source of N atom in all synthetic chemicals. With a demand >170 million metric tons annually, ammonia is among the “Big Four” industries that release half of the industrial emissions in the world [1]. Electrochemical strategies have emerged as an attractive technology to replace the conventional synthesis via Haber-Bosch process. As one of the only reliable room temperature systems to date [2-3], the electrochemical lithium-mediated N2 reduction to ammonia (LiNRR) has emerged as a promising candidate for renewables-based and decentralized ammonia production. In LiNRR, the activation of molecular nitrogen (N2) is preceded by the electrochemical deposition of metallic lithium in an organic solvent, which then reacts with N2 and undergoes protonation to release NH3, while significant fractions of the active material undergo various parasitic reactions [4]. Progress in recent years aimed at improving the faradaic efficiency, energy efficiency and long-term stability have been achieved via changing the salt [5-6] and proton donor compositions [7], which have been correlated with the structure and composition alterations of the Solid Electrolyte Interphase (SEI). However, fundamental understanding of the interplay between N2 reduction, parasitic reactions and speciation at the interface that drive efficiency and system instability is lacking.In this study, we aim to develop electrolyte design principles that govern the faradaic efficiency and electrode stability of lithium-mediated electrochemical N2 reduction. Taking inspiration from Li-metal battery [8], a variety of lithium salts and electrolyte compositions in tetrahydrofuran and ethanol were employed to evaluate their efficacy for ammonia synthesis. Physical descriptors to probe the solvation structure around lithium ions (Li+) were established and quantified via electrochemical (Li/Li+ redox potential) characterization, Raman spectroscopy and Infrared spectroscopy of the bulk electrolytes and Li interface characterization. Our study revealed a clear correlation between the NH3 faradaic efficiency, the extent of Li+-anion and Li+-solvent pairing and the driving force for electrolyte decomposition. By drawing a comprehensive connection between ammonia efficiency against bulk and interfacial descriptors, we could reveal the fundamental origin of different NH3 synthesis performances in different electrolytes. An order-of-magnitude improvement in faradaic efficiency can be obtained at the optimal electrolyte composition compared to state-of-the-art perchlorate or tetrafluoroborate electrolytes. Moreover, the transability of ammonia performance enhancement on a continuous flow cell setup is evaluated. Such fundamental insights that connect the bulk properties with interfacial chemistry during LiNRR will aid in engineering stable interfaces, resulting in a long-lasting, high-performing system for practical applications.

(Invited) Role of Ag in Ag-C Interlayer for Reversible Plating/Dissolution of Li-Metal for Anode-Free Li-Metal Solid-State Batteries

Reversible lithium metal plating/striping is a vital requirement to realize anode-free configuration of lithium-metal solid-state battery (LMSSB), and has remained as a challenge for long years. To improve uniformity and reversibility of lithium metal plating, interlayer formation on solid-state electrolyte has been proven to be an effective strategy. While various types of interlayers have been studied so far, Ag-C composite interlayer has attained excellent cycle performance (89 % after 1,000 cycles) and high loading capacities (> 6 mAh/cm2) simultaneously[Ref]. The mechanism of Ag-C composite interlayer is, however, not clear yet, due partly to lack of the most fundamental characteristics of Li-Ag alloys such as phase diagram and their electrochemical characteristics.Here, in this study, we have clarified the fundamental Li-Ag properties and their influence on the Ag-C composite interlayer in anode-free LMSSB configuration. We, first, unambiguously identified phase diagram of Li-Ag, their crystal structures and their thermodynamic and kinetic electrochemical characteristics. Next, we revealed phase transformations of Ag-C interlayer during charging and discharging via synchrotron operand XRD. Then, we clarified that the role of Ag in Ag-C interlayer for anode-free LMSSB is to maintain interfacial intimacy between the Ag-C interlayer and current collector, rather than their influence on the bulk properties of Li-metal. First, we renewed Li-Ag phase diagram and revealed their crystal structures by systematic studies of structural, thermal, and electrochemical characterizations. The newly identified phase diagram is different from conventionally recognized phase diagram in lithium-rich region. No Li9Ag phase, usually referred as γ 1 phase with incongruent decomposition, was absent. But, instead, Li3Ag and Li83Ag17 phases, respectively are present and their crystal structures were identified by analysis of XRD spectrum using data-science approach. Furthermore, electrochemical characterization revealed that the open-circuit potential of Li3Ag phases is only 4 meV above Li/Li+ equilibrium potential, very close to the lithium metal. Thus, the whole map of Li-Ag phase diagram together with electrochemical properties around room temperature was clarified. Having correctly identified phase diagram and crystal structures of Li-Ag alloys, we performed operand XRD of Ag-C interlayer during charging/discharging processes using synchrotron X-ray radiation source. It was revealed that during charging, phase transformations of Li-Ag nearly follows the equilibrium conditions. Slight deviation from quilibrium is that lithium-metal nucleation overpotential was observed before most Li-rich phase (Li83Ag17) appeared. This is due to very low open-circuit potential of Li3Ag, which leads to non-equilibrium Li metal plating with slight overpotential. During discharging, the thermodynamically unstable phase appeared at the end of discharging, due to slow kinetics of Li-Ag alloy in the Li-rich region. Given that the Li-Ag materials characteristics and Ag-C interlayer charge/discharge phase transformation behavior was clarified, we then characterized charge/discharge performance of anode-free LMSSB with Ag-C interlayer. For comparison, the same battery configuration but the Ag-C interlayer replaced with carbon interlayer was also characterized. Discharge rate-performance of Ag-C interlayer shows nearly constant discharge capacity with increasing current for higher than 3 mA/cm2, while that of carbon interlayer abruptly dropped within 1 mA/cm2, when the discharge current was increased with cycles. This result seemingly showed the improved diffusion of lithium in Li-Ag alloy, which, however turned out to be not right. This drop of rate performance in carbon interlayer was observed only in the 2nd or latter cycles but not in the first cycle, which indicate that the effect of Ag in Ag-C interlayer for high cycle capability is its enhanced adhesion between Ag-C interlayer and current collector, but not the bulk diffusivity in Li-Ag layer. This was further verified with cross-sectional SEM images.This study reveals the role of Ag in Ag-C composite interlayer, and provides insight about the design principles of the interlayer towards realization of anode-free lithium-metal solid-state battery. [Ref] Y. Lee et al. Nat. Energy 5, 299 (2020).

Investigation of Anionic and Cationic Redox Chemistry in P3-Type Na0.67[Zn0.3Mn0.7]O2 Layered Sodium Cathode with Zn Displacement

Oxygen redox-based layered cathode materials, such as P2/P3-types Nax[AyMn1-y]O2 (A=Li, Mg, Zn, vacancy), are of great importance to realize high-energy-density sodium-ion batteries (SIBs). In this work, we introduce a novel oxygen redox-based layered cathode material, P3-type Na0.67[Zn0.3Mn0.7]O2 with Na-O-Zn local configuration (Figure a,b). We investigate the effect of Zn doping on the electrochemical performance using a variety of methods such as galvanostatic potential cycling (Figure b), operando-X-ray diffraction (o-XDR) (Figure c), X-ray absorption near-edge structure (XANES), X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance (23Na NMR), atomic-resolution scanning transmission electron microscopy (STEM) and differential electrochemical mass spectroscopy (DEMS). O-XRD analysis reveals that P3 - Na0.67[Zn0.3Mn0.7]O2 material undergoes a phase transformation from P3 to O/P during charging and from O/P to P3 and finally to O3 during discharging (Figure d), which is also proved with the local structure transformations obtained by 23Na NMR. Moreover, STEM and XANES reveal the displacement of Zn from the transition metal (TM) layer to the Na layer. Therefore, the Na-O-Zn configuration and the possibility of Zn migration in the Mn4+ - based layered material are expected to play an important role in activating oxygen redox. As a result, our findings provide new insights into the reaction mechanism of P3-type oxygen redox-based cathode materials and a new design strategy for optimizing the bulk properties of SIB cathode materials. Figure. (a) Rietveld refinement of XRD pattern for P3-Na0.67[Zn0.3Mn0.7]O2 (NZMO) (inset: crystal structure of NZMO) (b) STEM-HAADF images of NZMO at fresh state (c) The 1st and 2nd charge-discharge cycles of NZMO tested at 13 mA g−1 (0.05C) (d) Operando-XRD pattern of NZMO electrode during the first charge-discharge cycle (e) Schematic image of structural evolution of NZMO during de/sodiation. Figure 1

Understanding the Multiple Roles of Solvation Structure in the Performance of Next-Generation Sodium Metal Battery Systems

Sodium metal batteries have become one of the most attractive targets for beyond-lithium electrochemical energy storage opportunities in recent years due to their low cost, high abundance, and sustainability when compared to popular lithium systems. The adoption of sodium metal batteries has been limited, however, by their instability and poor cycle life. Current efforts to resolve instability of the sodium metal anode have primarily focused on the adaptation of electrolyte systems (including solvents, salts, and additives) from the more researched lithium metal battery systems with some success.1 However, it has become clear that sodium metal batteries behave distinctly for their alkali counterpart, and will require new electrolyte design strategies. In order to inform solvation shell dynamics and SEI formation, this work explores 2 common salts (NaPF6 and NaTFSI) and 2 common solvents (diglyme and FEC) employed in sodium metal battery electrolytes. The selected components possess a range of desirable molecular structures bulk properties, allowing us to diagram the connections between their solvation structures and bulk solution phase properties. We achieve this by probing solvation shells with (1) Raman and (2) NMR spectroscopy, and following these chemical dynamics through to their impacts on electrolyte decomposition with in operando (3)electrochemical quartz crystal microbalance (EQCM) and SEI composition (4) XPS to morphology (5) SEM. Finally, we correlate these fundamental electrochemical and chemical observations to traditional cycling analysis as well as electrochemical impedance spectroscopy (EIS). We elucidate distinct roles of anion and solvent for ion transport and SEI formation in sodium systems, providing crucial understanding required for informed Na electrolyte design. 1. Sarkar, S.; Lefler, M.J.; Vishnugopi, B. Nuwayhid, R.B.; Love, C.T.; Carter. R.; Mukherjee, P.P.; Fluorinated ethylene carbonate as additive to glyme electrolytes for robust sodium solid electrolyte interface. Cell Reports Physical Science , 2023, 4, 101356.

Hybrid Mass Spectrometry Applied across the Production of Antibody Biotherapeutics.

Post expression from the host cells, biotherapeutics undergo downstream processing steps before final formulation. Mass spectrometry and biophysical characterization methods are valuable for examining conformational and stoichiometric changes at these stages, although typically not used in biomanufacturing, where stability is assessed via bulk property studies. Here we apply hybrid MS methods to understand how solution condition changes impact the structural integrity of a biopharmaceutical across the processing pipeline. As an exemplar product, we use the model IgG1 antibody, mAb4. Flexibility, stability, aggregation propensity, and bulk properties are evaluated in relation to perfusion media, purification stages, and formulation solutions. Comparisons with Herceptin, an extensively studied IgG1 antibody, were conducted in a mass spectrometry-compatible solution. Despite presenting similar charge state distributions (CSD) in native MS, mAb4, and Herceptin show distinct unfolding patterns in activated ion mobility mass spectrometry (aIM-MS) and differential scanning fluorimetry (DSF). Herceptin's greater structural stability and aggregation onset temperature (Tagg) are attributed to heavier glycosylation and kappa-class light chains, unlike the lambda-class light chains in mAb4. Hydrogen-deuterium exchange mass spectrometry (HDX-MS) revealed that mAb4 undergoes substantial structural changes during purification, marked by high flexibility, low melting temperature (Tm), and prevalent repulsive protein-protein interactions but transitions to a compact and stable structure in high-salt and formulated environments. Notably, in formulation, the third constant domain (CH3) of the heavy chain retains flexibility and is a region of interest for aggregation. Future work could translate features of interest from comprehensive studies like this to targeted approaches that could be utilized early in the development stage to aid in decision-making regarding targeted mutations or to guide the design space of bioprocesses and formulation choices.

First-principles calculations to investigate the bulk, electronic, optical and thermoelectric properties of BaGe[formula omitted]As[formula omitted] and BaGe[formula omitted]P[formula omitted] alloys

The structural, elastic, electronic, and optical properties of BaGe2As2 and BaGe2P2 have been theoretically investigated, but their thermoelectric properties have not been reported. The current work aimed at conducting an exhaustive study on the bulk, electronic, and optical properties as well as the thermoelectric property of BaGe2As2 and BaGe2P2 zintl phase compounds. Density functional theory implemented in Quantum ESPRESSO code combined with other processing codes such as Thermo−pw and BoltzTrap were employed in this study. The lattice constants computed were found to agree well with the other theoretical and experimental results, demonstrating validity of the study. Both compounds are brittle, elastically anisotropic and mechanically as well thermodynamically stable. The materials in this investigation were discovered to be semiconductors with indirect band gaps of 0.73 eV and 1.14 eV for BaGe2As2 and BaGe2P2 respectively. Therefore, both materials are appropriate for use in the electronics sector, notably in temperature control applications. The PDOS analysis suggests that P and As in BaGe2P2 and BaGe2As2, respectively, dominate the conduction band, whereas Ge dominates the valence band in both cases. The results also show that BaGe2P2 out-performs BaGe2As2 in terms of optical absorption coefficient. Both BaGe2As2 and BaGe2P2 are excellent p-type thermoelectric materials but BaGe2P2 has a greater figure of merit than BaGe2As2, making it a potential thermoelectric material. Lastly, the figure of merit values determined in this study are considered approximations since the lattice thermal conductivities of complex BaGe2As2 and BaGe2P2 compounds were not computed due to limited computational resources.

Comprehensive analysis of bulk and (001) surface properties of the quaternary Heusler compound CoTiFeGe

The study investigates the CoTiFeGe quaternary Heusler alloy, focusing on its bulk structure with various ordering types and its (001) surface terminations of ∗CoFe and ∗TiGe. Employing density functional theory (DFT), researchers analyzed the material's properties. Calculations of elastic constants provided insights into the alloy's mechanical properties. Electronic structure analysis, specifically the density of states and band structure for XA-type ordering, revealed half-metallic characteristics. Using both GGA and mBJ-GGA methods, the study found band gaps of 0.490 eV and 0.982 eV, respectively, confirming the alloy's half-metallic nature. Surface analysis showed that the ∗CoFe-terminated (001) surface loses its half-metallic ferromagnetic character, while the ∗TiGe-terminated surface maintains complete spin polarization. This finding has significant implications for potential spintronic applications. Optical property investigations of both bulk and (001) surfaces supported the material's semiconducting nature. The primary optical reflections were observed in the visible and infrared regions, with minimal loss in the same spectral range. The presence of absorption in the (001) surface suggests potential applications in optoelectronics. Additionally, the research explored the alloy's thermoelectric properties by examining its transport coefficients.