Poster Presentations
ABSTRACTS
P01 Evaluation of Effect of Microstructures on Mechanical Properties of Dual-phase Steel
MISATO SUZUKI, K. Shizawa, M. Muramatsu, Keio University, Yokohama, Japan
In this study, the effect of three-dimensional polycrystalline microstructures of dual-phase (DP) steel on mechanical properties is evaluated. DP steel is composed of a soft phase (ferrite) and a hard phase (martensite). The mechanical properties of DP steel depend on the spatial distribution of martensite, which contributes to strength, and ferrite, which contributes to ductility. DP steel microstructures are generated in two steps. For the first step, polycrystalline microstructures are generated by the multi-phase-field method. The multi-phase-field method predicts whether each grid point is within a crystal grain or grain boundary. Next, the results of the multi-phase-field method are used as initial states of the phase-field method that predicts martensitic transformation. Through these steps, microstructures with various martensite volume fractions and ferrite grain sizes can be obtained. The dislocation-based crystal plasticity finite element method is used to evaluate mechanical properties. The stress-strain relationship obtained from the crystal plasticity analysis is confirmed to be dependent on the martensite volume fractions. By taking into consideration the effect of dislocations, the stress-strain relationship is also found to vary with the ferrite grain sizes.
P02 Strain Phase Equilibria and Diagrams of Functional Materials
BO WANG, Lawrence Livermore National Laboratory, Livermore, USA; Long-Qing Chen, Penn State University, USA
Strain engineering has been established as a viable way to stabilize hidden phases and induce exotic phenomena in many low-dimensional solid-state materials. A phase diagram describing the equilibria of phases and domain variants as a function of strains and other thermodynamic variables is invaluable to guide the strain engineering. Here, we propose a universal theoretical framework based on thermodynamics to establish the strain phase diagrams of any solid-state functional materials, without a priori assumptions on the multi-phase/multi-domain coexistence or substantial computational workload. We apply this approach to establish the strain phase diagrams of various functional materials that undergoes structural transformations and discuss the generalized Gibbs phase rules, critical and multi-critical points, universal topological characteristics of the diagrams, and demonstrate a graphical approach to determine the content fractions of the coexisting phases/domain variants. Our theoretical approach offers a universal understanding of the phase equilibria of solid-state materials subject to arbitrary anisotropic strains, enabling efficient construction of strain phase diagrams in high dimensions that would be tremendously useful for strain engineering of quantum materials.
P03 3D Printing of Clay Components for Improving Passive Indoor Moisture Buffering
V. Gentile1, J.D. Vargas Velasquez1, S. Fantucci1, G. Autretto1, R. Gabrieli2, P. Kumar Gianchandani2, 3, M. Armandi2, F. Baino2, 1Department of Energy (DENERG), Politecnico di Torino, Turin, Italy; 2Department of Applied Science and Technology (DISAT), Politecnico di Torino, Turin, Italy; 3Department of Textile Engineering, Mehran University of Engineering & Technology, Jamshoro, Sindh, Pakistan
This study focuses on implementing a novel approach in which 3D-printed clay matrices were designed as a passive comfort solution to enhance indoor moisture buffering and air quality. Liquid Deposition Modeling additive manufacturing and parametric design were implemented to develop the components, which were characterized for having an increased specific surface exposed to air and moisture per volume unit, yielding to a significant enhancement of moisture buffering capability. The components showed a significant increase in the practical Moisture Buffering Value (MBV) and mass reduction compared to a solid clay reference. Furthermore, this research analysed the influence of two stabilization techniques on the moisture uptake capacity of the samples, i.e. thermal treatment at different temperatures between 600-1000°C and mixing with calcium hydroxide paste within the 10-40% range. SEM and XRD analyses of the samples showed a correlation between microstructural modifications and variations of moisture uptake capacity and MBV. In addition, nitrogen adsorption-desorption measurements revealed that sample porosity decreased as the temperature of the thermal treatment increased, showing a correlation with the decrease of practical MBV.
P04 Change in Potential Energy as Descriptor for Nano-particle Coalescence
a. damianidis1, Y. Wang1, P. Grammatikopoulos1, 2, 1Department of Materials Sciences and Engineering, Guangdong Technion - Israel Institute of Technology, Shantou, Guangdong, China; 2Particle Technology Laboratory, Institute of Process Engineering, Department of Mechanical and Process Engineering, ETH Zürich, Zürich, Switzerland
Various metrics have been used in the literature to describe the progress of nanoparticle (NP) coalescence. Typical examples include the neck radius, average distance between the NPs’ centres of mass, gyration radii, sphericity, surface area changes, etc. Here, we introduce a new descriptor, i.e., the overall reduced change in potential energy between the initial and final configurations. As potential energy of the initial configuration (per atom) we assume the value while two NPs are still isolated from each other. We compared potential energies after 100 ns of MD simulation runs; the final values of these plots reveal the percentage of the overall change in potential energy. We normalised these differences over the initial potential energy of the system to enable comparisons between runs at different temperatures. To benchmark our new descriptor, our definition is similar to that of the overall change in surface area, one of the most common and reliable metrics. Multiple linear regression analysis revealed that our new metric was reliable when no phase transition occurred. Therefore, it may become a valuable new coalescence metric at either low or high temperatures, especially considering that potential energy is a standard output property in atomistic simulations.
P05 Ionomer Cements Containing Bioglass and Glass-ceramic Reinforcements
A. Zandi Karimi, E. Rezabeigi, R.A.L. Drew, Mechanical, Industrial and Aerospace Engineering, Concordia University, Montreal, Canada
Incorporation of bioactive glasses into glass ionomer cements has led to successful improvements in properties, whereas incorporation of a bioactive glass in GICs has not been investigated. An Al-free GIC has been developed using various combinations of 45S5 Bioglass® and its corresponding glass-ceramic as filler components. The glass-ceramic with high crystallinity were employed because acting as both as a mineralizing and reinforcing agent. Various strengthening mechanisms were observed including crack deflection and crack-tip shielding. The effect of particle size distribution containing both micron- and nano-sized particles was investigated. The toxic effects of Al are avoided while still obtaining good bonding between the cement and the surrounding hard tissue(s) through interfacial biomineralization and adhesion.
P07 Inkjet Printing of Ceramic Coatings from Polysilazane and SiC Nanoparticles for High-temperature MEMS Applications
A. QAZZAZIE-HAUSER1, K. Honnef1, T. Hanemann1, 2, 1Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany; 2Institute for Applied Materials IAM-WK, Karlsruhe Institute of Technology KIT, Eggenstein-Leopoldhafen, Germany
Due to their extraordinarily versatile processability, preceramic polymers are attractive candidates for additive manufacturing of ceramic components. In this study, coatings based on polysilazane as preceramic polymer and silicon carbide (SiC) nanoparticles were deposited by inkjet printing on silicon wafers to develop new composite materials for high-temperature MEMS applications. Polysilazane offers several advantageous properties, such as excellent adhesion on many surfaces, high thermal and chemical stability. Furthermore, after pyrolysis it can be converted into silicon carbonitride with SiC nanodomains. Since SiC is a semiconductor, its electrical properties are expected to be measured in the final coating. The electrical conductivity will be measured by the four-probe method. The thin films were polymerized photochemically followed by pyrolysis in nitrogen atmosphere. The polymerization and crosslinking progress were investigated in detail by FTIR spectroscopy. Additionally, the decomposition and the pyrolysis process of the coatings was analyzed thermogravimetrically. Before printing, rheological and surface tension characterizations of the ink were conducted to fulfill the requirements of the inkjet printing process. The ink exhibits Newtonian behavior.
P08 Coarse-grained Molecular Dynamics Simulations on Aggregation and Dispersion Mechanisms of Organically Modified Nanoparticles
M. NAKAMURA1, K. Jojima1, R. Taniai1, Y. Ootani1, N. Ozawa2,1, M. Kubo1, 2, 1Institute for Materials Research, Tohoku University, Aoba-ku, Sendai, Japan; 2New Industry Creation Hatchery Center, Tohoku University, Aoba-ku, Sendai, Japan
Nanoparticles are characterized by their quantum size effect and large surface area. Their unique physical properties have been applied to electronics, magnetism, etc. For mass production of nanoparticles, nanoparticles are often handled in organic solvents. To maintain the unique physical properties of nanoparticles, it is important to disperse nanoparticles in organic solvents. Therefore, nanoparticles are usually coated with the organic ligands to prevent aggregation. It is well known that the dispersibility of organically modified nanoparticles (OMNP) strongly depends on the solvents. Therefore, in the present study, we employed a coarse-grained molecular dynamics method for clarifying the aggregation and dispersion mechanism of OMNP. Here, we focused on organically modified CeO2 nanoparticles, and hexane, tetradecane, cyclohexane, and benzene are used for the organic solvents. Our simulation results indicate that the bundling of the ligands is an important factor for the aggregation and dispersion of OMNP. The number of bundled parts obtained by our simulations corresponded to the experimental dispersibility. Furthermore, we also revealed that the solvent penetration into the ligands contribute to ligand swelling, leading to the increment of the dispersibility of the OMNP.
P09 Multiscale Modeling of Nanoparticle Synthesis by Pulsed Laser Ablation in Liquid
CHAOBO CHEN, L.V. Zhigilei, Materials Science and Engineering, University of Virginia, Charlottesville, VA, USA
Pulsed laser ablation in liquid (PLAL) has emerged as a promising technique for synthesis of chemical-clean nanoparticles (NP) for catalysis and other applications. In PLAL, the fast laser energy deposition brings the target material to the supercritical state and triggers a sequence of far-from-equilibrium processes leading to the NP formation. To study these processes, we developed a multiscale model combining a two-temperature model for the description of laser excitation and subsequent relaxation of electrons, atomistic molecular dynamics (MD) modeling of laser-induced phase transformations, coarse-grained MD representation of the ablation plume - liquid interaction, hydrodynamic modeling of the shock wave propagation in the liquid environment, and electromagnetic (EM) model based on the solution of Maxwell equations for predicting transient optical properties of the ablation plume. Large-scale simulations (>100 million atoms in MD and >500 million cells in EM) of PLAL of FeNi targets performed with this model have provided insights into the rapid phase transformations occurring within a laser spot, revealed the existence of three distinct fluence regimes of the NP formation, and suggested new avenues for enhancing the efficiency of the NP production.
P10 Model and Analysis of the Solid-state Crystal-clad Growth from the Ti:sapphire Core
sheng-lung huang, National Taiwan University, Taipei, Taiwan
Ultra-broadband wavelength-swept lasers are essential for high-speed optical coherence tomography for cancer diagnosis at the early stage. Single-mode Ti:sapphire crystalline fiber gain medium can be developed by solid-state growth from the crystalline core perimeter. With high-temperature sintering, the crystalline core boundary can migrate by aligning the alumina grain orientation with the core to form crystalline clad. To model and analyze the sintering temperature and time effects on the crystallographic orientations of ambient grains, end-face images of the cladded crystal fiber were taken using the electron backscatter diffraction method. For a 1650 °C sintering time of 24 hours, the ambient grains around the crystalline cladding grew anisotropically to around 100 μm. The crystallographic orientations of neighboring grains in the clad rotated to a small misorientation angle to the crystalline core. However, some big adjacent grains with large misorientation angles were hardly rearranged due to the significant free energy gaps. The crystallographic orientation distribution of ambient grains concentrates around a smaller number of crystallographic orientations. The influence zone of the cladding and core on the crystallographic orientation was modeled and analyzed.
P11 Effect of Mechanical Stress in Thin Hafnium Oxide Films
E.B. KALIKA, V.V. Mikheev, I.G. Margolin, A.A. Chouprik, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
Since the discovery of the ferroelectric properties of hafnium oxide, it has been considered one of the most promising materials in electronics, especially for application in ferroelectric non-volatile memory devices, due to the ability to demonstrate ferroelectricity even in nanometer thick films and its compatibility with CMOS conditions. However, the origin of ferroelectricity still remains an open question. It is now being debated whether the ferroelectric phase in HfO2 could originate due to the mechanical stress that is created in the film during the annealing process. Current research investigates the effect of mechanical stress on the dielectric and ferroelectric properties (particularly, polarization, band gap and dielectric permittivity) of hafnium oxide films, both by first principles calculations and experimentally on Hf0.5Zr0.5O2 capacitors. We have shown that, on the one hand, it is possible to adjust the properties of the HfO2 film by varying the mechanical stress and, on the other hand, the difference in nominally identical devices can be due to different mechanical stresses.
P12 Computational Modeling of Semimetallic, Half-metallic and Other States in the Gd-Sb Compounds with Strong Electron Correlations
a.v. lukoyanov, R.D. Mukhachev, S.T. Baidak Institute of metal physics Mikheev UB RAS, Ekaterinburg, Russia
Quantum materials include a number of materials with anomalous properties. These properties are promising for spintronic and quantum applications. In this work, electronic structures of the Gd and Sb-based intermetallic materials have been modeled within DFT+U accounting for strong correlations of the electrons from the 4f shell in five Gd-Sb compounds. GdSb is found to be a semimetal with the topological electron pocket along G-X-W and hole pockets along L-G-X. Our calculations show that addition of nickel results in the band gap for GdNiSb. These semiconducting properties can be changed to the metallic ones in case of a cell contraction. In Gd4Sb3, this material is a half-metal with the band gap of 0.67 eV only in the minority spin projection. GdSb2 is revealed to have the metallic state, remarkably, its band structure has a Dirac-cone-like feature between G and S. The results are published in Int. J. Mol. Sci. 24, 8778, 2023. Thus, in this work, in the electronic and magnetic properties of the Gd-Sb compounds a variety of the semimetallic, half-metallic, semiconducting, or metallic states, as well as topological features in some of them, are found which can be related with different anomalous properties of the compounds. This research was supported by RSF 22-42-02021.
P13 A Highly Effective Data Modeling Approach for Transformers based on 1D CNN Methods for Improving SOC Estimation Accuracy
JUNGWOO HO, B. Han, C.S. Kim, Y. Kim, S. Lee, D. Yun, D. Chung, J. Jeon, Department of Advanced Battery Convergence Engineering, Dongguk University, Seoul, South Korea
Battery State of Charge (SOC) estimation is important to ensure batteries safety and efficiency. However, the issue of estimation inaccuracy persists due to the intricate electrochemical dynamics of batteries and the constantly changing ambient conditions [1]. Overcoming this challenge has been made possible through recent algorithmic advancements and the accessibility of comprehensive datasets, enabling SOC estimation using advanced deep learning techniques. In the battery SOC estimation method based on deep learning, recurrent neural networks are the majority. However, promising advancements arise with the application of Transformer models, initially designed for natural language processing, particularly in the realm of time series prediction [2]. Furthermore, data modeling has received much attention because it is an important step in determining the efficiency of deep learning methods. This paper proposes a data modeling approach for transformers, enhancing SOC estimation accuracy through a 1D CNN-based method.
[1] Z Wang, G Feng, D Zhen, F Gu, A Ball, Energy Reports 7 (2021): 5141-5161.
[2] Yuefeng Liu, Yingjie He, Haodong Bian, Wei Guo, Xiaoyan Zhang, Journal of Energy Storage 52 (2022) 104664.
P14 Stability and Structure of the Aqueous LiTFSI/LiCl Interface
h. wood, H. Burnett, R. Dryfe, P. Carbone, University of Manchester, Manchester, UK
It has recently been demonstrated that LiTFSI/LiCl solutions can form stable liquid-liquid biphasic systems when both electrolyte phases have sufficiently high concentrations, specifically in the "water-in-salt" regime. In this work, we combine molecular dynamics simulations and experimental analysis to investigate the molecular structure of the interface and how this correlates with its thermodynamic stability. We observe that TFSI$^-$ anions exhibit surfactant-like properties, leading to a reduction in surface tension and an increase in interfacial thickness due to aggregation at the interface with increasing LiTFSI concentration in liquid-air systems. We investigate the interfacial structure and stability of LiCl-LiTFSI biphasic systems. Our findings indicate that increasing the concentration of both salts improves the stability of the liquid-liquid interface, as evidenced by the increasing surface tension and decreasing interfacial thickness. The orientation of the amphiphilic TFSI$^-$ anions varies depending on the composition of the second phase and this structural variation influences the interfacial properties of these systems.
P15 Enhancing the Electrolyte Wetting in Electrodes of Lithium-ion Batteries
DONG HYUP JEON, Dongguk University, Gyeongju, South Korea
Lithium-ion batteries (LIBs) are widely used in information technology (IT) applications and preferred system for electrical energy storage (EES) in electrical vehicles (EVs) and hybrid electrical vehicles (HEVs) because of their high power and energy densities. The LIB electrode is composed of porous electrode, liquid electrolyte and separator. Through the impregnation process, liquid electrolyte permeates the pore space of porous electrode to constitute the transport paths for lithium ion. The wettability of porous electrode by the electrolyte is one of the critical factors that affect the battery performance and cycle life. Insufficient wetting of electrolyte can cause poor utilization of the electrode capacity and increasing electrolyte resistance, resulting in degradation of performance and cycle life. In this study, the electrolyte transport dynamics in the two-dimensional electrode structure of LIB numerically investigated using the multiphase lattice Boltzmann method (LBM). The LBM is a promising computational fluid dynamics (CFD) tools for simulation of multiphase and immiscible flow, and successfully simulates the complicated microscopic behavior of a liquid electrolyte in a porous electrode of LIBs. Using the LB model, we studied the wetting mechanism in the electrode.
P16 A Deep Learning Model for Driving the Interaction of Data-variability Features in Dynamic-stress Time Series’ Information
BYEONGJIK Han, J. Ho, J. Ahn, Y. Kim, D. Chung, J. Jeon, Department of Advanced Battery Convergence Engineering, Dongguk University-Seoul, South Korea
A state of charge (SOC) estimation plays a very important role on the stable operation of lithium-ion batteries in electric vehicles (EVs). This article proposes a novel accuracy-tuning LSTM (a-LSTM) framework to learn both explicit and implicit interaction of long- and short-term factors for accurate SOC estimation, which is attributed to enhancing the extraction of long- and short-term features by modeling the data complexity of time series information variability. The proposed a-LSTM contains a data-complexity modeling LSTM (d-LSTM) module interworking with conventional LSTM (c-LSTM) module, which learns characterizing time-series’ complexity features. Experimental results show that the proposed a-LSTM exhibits enormously improved SOC accuracy of lower loss than c-LSTM where the root mean squared error (RMSEs) of a-LSTM are is 3.719e-5 less than 3.297e-4 of c-LSTM. Further, it also appears that the a-LSTM indicates remarkably well-optimized performance even in the presence of dynamically rapid change. The proposed a-LSTM model overcomes the deficiency of LSTM in weak modeling the long-time dependency and completes the long- and short-term feature interaction by efficiently modeling time series data.
P17 A Comparison of LSTM and GRU Networks using many to many method for State of Charge estimation on EV
yunsun kim, B. Han, C.S. Kim, J. HO, J. AHN, S. LEE, D. Chung, J. Jeon, Dongguk University, Seoul, South Korea
Accurate State of Charge (SOC) estimation is crucial for the safety and efficiency of electric vehicle (EV) battery management system, challenged by complex battery dynamics and changing environmental conditions. This paper focuses on leveraging data-driven deep learning methods, specifically Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU) neural network algorithms, to compare SOC estimation accuracy. The paper employs the many-to-many technique to retain output across all inputs in the recurrent neural network (RNN) series and reduce the feature vector dimension using many to one RNN, ultimately aiding in precise SOC computation. Experimental results show that the GRU exhibits a better performance in SOC estimation than LSTM, yielding 1.5850% of root mean squared error (RMSE) and 1.2918% of mean absolute error (MAE), respectively. LSTM shows 1.7275% of RMSE and 1.4327% of MAE, which are 8.25% and 9.84% higher prediction errors than GRU, one by one. Other experimental studies have concluded that GRU generally shows superior performance on smaller datasets compared to LSTM. In this study, when experimented with the same small dataset as previous studies, the results showed that GRU had higher performance.
P18 Computational Modeling of Mechanical Properties and Mechanism of Keratin-based Polymer Materials
Chia-Hung Wu, Chia-Ching Chou, Institute of Applied Mechanics, National Taiwan University, Taipei, Taiwan
This study investigates the properties of biomedical materials composed of alpha keratin and glycol chitosan, which are known for the flexibility, biocompatibility and biodegradability in the fields of tissue engineering and 3D printing. Here, we applied molecular dynamics simulations to model material structures and interactions at a microscopic scale at different degrees of methacrylate modification and material concentrations. Our simulation results revealed that keratins with methacrylate modification have intermolecular hydrogen bonding and end-to-end distances. On the other hand, methacrylate modification leads to more intramolecular hydrogen bonding in glycol chitosan and fewer intermolecular hydrogen bonds, indicating reduced hydrogen bonding with water and other high-molecular-weight compounds. We also observed that the system with lower glycol chitosan concentration or higher keratin concentration have the decreasing intermolecular hydrogen bonding interaction and more loosely distributed, lower-interaction polymer configuration, which aaligns with the lower Young's modulus and tensile strength observed in experiments. The in-depth atomic-scale analysis serves to enhance our understanding of keratin/glycol chitosan material properties and explore potential application.
P19 Structural Superlubricity of Macroscale Patterned Contact Network: A Simulation Study
VIET HUNG HO, M. Gianetti, B. Haugen, A.S. de Wijn, Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
In recent decades, structural superlubricity has gained significant attention, emerging as a key approach in lubrication. While structural superlubricity can be observed, e.g. between incommensurate two-dimensional materials, at the nano or microscale, achieving it at the macroscale remains a challenging endeavor. Thus, further research on macroscale superlubricity is essential to expanding it into technological applications. In this study, we conducted theoretical investigations into the friction behaviors of patterned networks containing a large number of microscale contacts using a combination of molecular dynamics simulations and the discrete element method. Additionally, various normal contact models, including non-adhesive model (Hertz), adhesive models (John-Kendall-Roberts and Derjaguin-Muller-Toporov), and Mindlin model, were used to examine the friction at different conditions. Our finding revealed the substantial dependence of friction on the load distribution across each microscale contact. These results suggest that with optimized geometrical parameters, specifically size and distance between microscale contacts, a superlubric contact network can be achieved. Furthermore, we discussed the influence of adhesion on the superlubricity of the proposed patterned network.
P20 Multiscale Computational Study of Surface Modification by Nonlinear Laser-induced Surface Acoustic Waves
YUAN XU, L.V. Zhigilei, University of Virginia, Charlottesville, VA, USA
Surface acoustic waves (SAWs) are used in many practical applications ranging from non-destructive evaluation of material’s mechanical properties to chemical sensing. Moreover, a number of experimental studies have demonstrated the ability of SAWs to substantially enhance the rates and selectivity of heterogeneous catalytic reactions. The physical explanation of this phenomenon remains unclear but a possible hypothesis is that a sufficiently strong SAW may be capable of producing structural changes on the surface, which in turn may lead to the activation of catalytic reactions. Therefore, multiscale modeling was applied to investigate the mechanical interaction between the intense SAWs and a platinum substrate. Firstly, continuum-level simulations were conducted to explore the ability of laser pulses to generate SAWs that are sufficiently strong for the formation of a shock front during nonlinear wave propagation. Secondly, large-scale molecular dynamics simulations were performed to investigate the surface structure modifications produced by the nonlinear propagation of SAWs. The focus of the analysis of the simulation results was on identification of the conditions (stress state) leading to the onset of SAW-induced emission of dislocations and their evolution.
P21 Computational Fluid Dynamics (CFD) Simulations on Optimal Designs and Performances of Various Operating Conditions in a 20kWe Class Solid Oxide Electrolysis Cell (SOEC) Stack
SANG SHIN PARK, Sun-dong Kim, Korea Institute of Energy Research (KIER), Daejeon, South Korea
The performances efficiencies in a solid oxide electrolysis cell (SOEC) stack have been decided by flow channel in cell. In this work, In order to optimal design of flow channel, the computational fluid dynamics (CFDs) are carried out with performances of various operating conditions in a solid oxide electrolysis cell (SOEC) stack considering pressure drop and fluid pattern. The CFD simulations were calculated with 4 flow channel patterns and 3 operating conditions. Optimal design factors were derived by comparative analysis and validations of our CFD simulation results and experimental results. Besides, the performances in a 20 kWe class SOEC stack were also predicted for temperature, fluid, and pressure distributions by our CFD simulations. Therefore, the optimal design factors for flow channel and the optimal operating condition were derived by considering pressure drops and flow distributions.
P22 Molecular Dynamics Simulations of Illite Clay Surface and Particle
GE LI, A.S. de Wijn, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
Illite clay is the predominant component of Norwegian quick clay, notorious for its rapid transformation from solid to liquid under specific pressure conditions. Current stabilization methods rely on cement and lime, contributing to significant CO2 emissions. To prompt the exploration of environmentally friendly alternatives, understanding the nanoscale mechanical interactions between illite particles is crucial, where the thickness of the electrical double layer (EDL) depends on salt types and concentrations. This study focuses on non-equilibrium molecular dynamics simulations of illite particle-surface contact, aiming to unveil the relationship between this interaction and EDL variations induced by various salts, including NaCl, KCl, CsCl, MgCl2, and CaCl2.
P23 Molecular Dynamics Simulation of the Effect of Dopant Distribution Homogeneity on the Oxide Ion Conductivity of Perovskite-type LaInO3
M.-Y. Yoon1, K. Kim1, S.-M. Jeong2, Hae-Jin Hwang1, 1Inha University, Incheon, South Korea; 2Korea Institute of Ceramic Engineering and Technology, South Korea
Molecular dynamics simulations are conducted to study oxide ion conduction in Ba-doped LaInO3, a type of cubic perovskite oxide. In a previous study, we reported that the Ba dopant forms oxygen vacancies and narrow bottlenecks that function as a barrier to the movement of oxide ions. In this further study, we analyze the effects of dopant distribution on the oxide ion conductivity in Ba-doped LaInO3. The results show that the ionic conductivity of Ba-doped LaInO3 is strongly dependent on the dopant distribution. The Ba-rich region plays a crucial role in decreasing the ionic conductivity. Consequently, a homogeneous dopant distribution without a Ba-rich region is estimated to improve the ionic conductivity of Ba-doped LaInO3.
P24 Improvement of the Electrochemical Activity of WO3 Nano-structures Incorporating Sulfur for Energy Storage Application
G. Roselló-Márquez, D.M. García-García, M.Cifre-Herrando, J. García-Antón, Ingeniería Electroquímica y Corrosión (IEC), Instituto Universitario de Seguridad Industrial, Radiofísica y Medioambiental (ISIRYM), Universitat Politècnica de València, Valencia, Spain
Nowadays, the energy issue has become the greatest challenge and has drawn global interest in current society. Optimizing the morphological and structural configuration of lithium-ion batteries (LiB) is crucial for enhancing their performance. This study investigates the impact of WO3 nanostructures on Li-ion battery behavior. Firstly, nanostructured WO3 thin films were synthesized through electrochemical anodization. These films were subjected to an annealing treatment at 600°C in an air environment for 4 hours. Additionally, WO3/WS2 electrodes were prepared via an in situ sulfurization process of WO3 using tungsten trioxide and thiourea as precursor materials under argon. A morphological and composition characterization of the two electrodes was conducted using techniques such as X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), Raman spectroscopy, and Field-Emission Scanning Electron Microscopy (FE-SEM). Electrochemical properties were analyzed through galvanostatic charge/discharge cycling and Electrochemical Impedance Spectroscopy (EIS). In conclusion, the WO3/WS2 nanostructures exhibited the best performance. They demonstrated the highest discharge capacity and excellent cycle stability, reaching a specific capacity of 530 mA·h·g−1.
P25 The Study of Indium-ion Diffusion for Multilayer Indium Tin Oxide Thin Films via Optoelectronic Characterization and Neutron Reflectometry
N. Xia1, J. Keum2, 3, A. Ievlev3, I. Ivanov3, V. Lauter2, R.A. Gerhardt1, M. Mays1, 1School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, USA; 2Neutron Scattering Division, Oak Ridge National Laboratory, USA; 3Center for Nanophase Materials Science, Oak Ridge National Laboratory, USA
Indium Tin Oxide (ITO), a transparent conducting oxide, is applied industrially as an electrode for usage in LEDs, computers/phone screens, and photovoltaic devices. Previous research has suggested that Indium diffusion into organic layers occurs as a function of device usage for sputtered ITO films.[1] This is unfavorable as this phenomenon leads to device degradation. In this study, we investigated the possible mobility of indium ions by characterizing multilayer ITO films with ToF-SIMS, Neutron and X-Ray reflectometry on ITO films deposited via spin coating. X-Ray and Neutron scattering length density results indicate peaks and troughs located at the interfacial layers between the individual layers of the ITO thin films. These features are a function of Indium-ion scattering length density being different in X-ray vs neutron scattering. Furthermore, ToF-SIMS results support the conclusion that increased Indium-ion content is present at the interfaces, confirming that diffusion of Indium to the interfaces occurs in multilayer ITO thin films. This effect was found to be independent of the substrates used and will need to be corroborated by conducting experiments on films deposited onto organic substrates.
[1] S.T. Lee et al., https://doi.org/10.1063/1.124708
P26 Robust Closed-loop Linear Control of NiTinol Wires
B. TONDU, Institut National de Sciences Appliquées, Campus de Rangueil, Toulouse, and LAAS/CNRS, Toulouse, France
NiTinol wires are typical low-priced thermoelectric actuators, easy to implement, and able to lift high loads with respect to their own mass and dimension. An accurate control of the contraction of the wire is however essential for practical applications. We developed an original set-up making possible the open-loop control of NiTinol wires in response to current steps and sine-waves, and also its positioning closed-loop control by means of a laser pointing on a light box inside which are embedded known masses. Open-loop control is used for identifying the wire contraction and elongation, in response to various current steps. The result is a model mixing a linear part and a nonlinear part. Such a model is then used for specifying a PID-based closed-loop control. Reported experimental step responses for desired positions, in a range of several millimeters, exhibit both very satisfying response times for a null steady state error. The proposed controller also gives very satisfying results in tracking error when desired sine-waves are considered. Moreover, the same controller, with same parameters, appears to be adapted to similar step and sine-wave responses with embedded loads up to 2 kg, without significative loss in response time and accuracy.
P27 A High Efficiency Bromine-complexing Agent for Zinc-bromine Flow Batteries: 1,2-dimethyl-3-ethylimidazolium Bromide Compound
Changseong Kim, Byeongjik Han, Sohyeon Lee, Deokhee Yun, Daewon Chung, Joonhyeon Jeon, Department of Advanced Battery Convergence Engineering, Dongguk University-Seoul, Seoul, South Korea
In zinc-bromine redox flow batteries (ZBBs), the weak molecular structure and stability of bromine-complexing agent (BCA) sometime negatively affect battery’s overall performance. Such performance decrease is seriously and rapidly accelerated with increasing temperature of electrolyte in working ZBBs. This article introduces an organic BCA which is a 1,2-dimethyl-3-ethylimidazolium bromide (C7H13BrN2) with planar (flat) molecular structure. The proposed BCA significantly contributes to apparently enhancing reaction kinetics and reversibility of Zn2+/Zn(s) and Br-/Br2 redox couples, by strong electrostatic shielding effect and bromine-capture/release (along with strong bromine-binding strength). Experimental results exhibited most apparently enhanced reaction kinetics and reversibility of Zn2+/Zn(s) and Br-/Br2 redox couples in working ZBB electrolyte, resulting in not only 4.88(1.73) and 15.14 (5.47) times higher diffusion coefficient and specific capacitance of Zn2+ (Br-) ion than the pristine one, respectively, but also 2.4 and 3.1 times lower charge-transfer and Warburg-diffusion resistances. Further, it was also experimentally shown to lead to improved current (voltaic) efficiency of averagely 98.25 (86.19) % which are 5.53 (7.29) % higher than the pristine one.
P28 Descriptors of the Surface Energy Based on the Crystal Structure
YOYO HINUMA1, S. Yasumura2, T. Toyao3, T. Kamachi4, Ken-ichi Shimizu3, 1AIST, Japan; 2University of Tokyo, Japan; 3Hokkaido University, Japan; 4Fukuoka Institute of Technology, Japan
Identification of the most stable termination of a crystal is important but costly. Using descriptors that reveal terminations with relatively low surface energies without explicitly conducting first principles calculations of surface properties leads to efficient use of computational resources. Intuitively, the energy required to cleave a surface is strongly correlated with the number of bonds that need to be broken per unit area. Therefore, the number of broken bonds per unit area, or the density of unsaturated coordination, is defined as a descriptor named "unsaturated coordination index". The definition of "coordination" itself is, unfortunately, ambiguous. For example, the maximum (cutoff) bond length must be specified in advance for each crystal. In addition, bond breaking is treated using a Heaviside function of length, and bonds are either "bonding" or "not bonding". Gradually weakening interactions as the bond length increases cannot be reflected. For this reason, we additionally developed two descriptors, "atom proximity function of a plane" and "surface roughness index," that do not use the concept of bonding. The design of these descriptors do not assume specific chemistries. Application to binary oxide systems will be discussed in the presentation.
P29 Unveiling New Ferroaxial Material via High-throughput Virtual Screening and Experimental Verification
RYUSUKE MISAWA1, S. Yamagishi2, T. Hayashida3, T. Murata1, S. Hirose1, T. Kimura3, 1Murata Manufacturing Co., Ltd., Japan; 2Department of Advanced Materials Science, University of Tokyo, Japan; 3Department of Applied Physics, Graduate School of Engineering/Faculty of Engineering, The University of Tokyo, Japan
High-throughput database screening is a surging trend in recent materials science. We employed this approach, combined with ab-initio calculations and experimental verifications, to discover new ferroaxial materials with unique rotational structural distortions and exhibit the electrogyration(EG) effect, which enables electrical tuning of optical rotation. We initiated our research by focusing on glaserite-type oxide family, X(□;1)Y(□;2)[M(TO4)2]. We used formula-based screening and symmetry detection algorithms to search materials database for potential candidates. This exploration led to the identification of K2Zr(PO4)2 as a promising ferroaxial properties. Experimentally, we confirmed that the crystal exhibits the EG effect at room temperature and undergoes ferroaxial phase transition around 700 K, that were supported by ab initio phonon calculations. To expand our search, we conducted more extensive screening of ICSD database. In this presentation, we propose several prototype compounds for subsequent experimental investigation. Our research not only highlights K2Zr(PO4)2 as a new member of ferroaxial materials but also validates our integrated approach as an effective strategy for discovering new materials with structural phase transitions and associated functionalities.
P30 A Framework for a High Throughput Screening Method to Assess Polymer/Plasticizer Miscibility
L. SMITH1, A. Karimi-Varzaneh2, S. Finger2, G. Giunta3, A. Troisi4, P. Carbone1, 1University of Manchester, Salford, UK; 2Continental Reifen Deutschland GmbH, Germany; 3BASF, Germany; 4University of Liverpool, Department of Chemistry, UK
Polymer composite materials require softening to reduce their glass transition temperature and improve processability. To this end, plasticizers, which are small organic molecules, are added to the polymer matrix. The miscibility of these plasticizers has a large impact on their effectiveness and therefore their interactions with the polymer matrix must be carefully considered. Many plasticizer characteristics, including their size, topology and flexibility, can impact their miscibility and the current trial-and-error approach is very ineffective. In this work, using a dataset of 40 plasticizers, we identify topological and thermodynamic descriptors that are proxy for their miscibility. Using ad-hoc molecular dynamics simulation set-ups, we establish correlations between the plasticizers’ topology, internal flexibility, thermodynamics of aggregation and their degree of miscibility and use these to classify the molecules as miscible or immiscible. The fully automated method is able to screen molecules with high miscibility potential on which further simulations or experiments can be performed. This procedure enables a 10-fold reduction of the test space and provides the basics for the development of a simulation procedure which can efficiently screen thousands of plasticizers.
P31 The Connection Between Power Dissipation and Energy Consumption in Memristive Devices during the Programming Phase
E. MIRANDA, F.L. Aguirre, J. Suñé, Universitat Autònoma de Barcelona, Cerdanyola del Valles, Spain; E. Piros, T. Kim, P. Schreyer, J. Gehrunger, T. Oster, K. Hofmann, C. Hochberger, L. Alff, Technische Universität Darmstadt, Darmstadt, Germany
We demonstrate that when programming a memristor or a resistive switching device there is a tradeoff between power dissipation and energy consumption. This interdependence arises because of the role played by the time-dependence of the programming signal. For instance, rapid varying signals are associated with large set voltages which increases the maximum power dissipated. On the contrary, slow signals yield high energy consumption because of the large voltages required under finite-horizon constraints. Considering the equations of the Dynamic Memdiode Model (DMM), electron transport and ion/vacancy displacement, we investigate in detail the consequences of selecting alternative programming trajectories for setting the same final conductance state in a fixed time. We show that assuming an incorrect switching dynamics for the memory state of the device leads to unphysical results. These issues are critical when dealing with hundreds or thousands of memristors in a crossbar array configuration typical of a neuromorphic system.
P32 Photothermal Crosslinking of Zirconium-Oxo Clusters for High Performance Dielectric and Memristor Applications
Myung-Gil Kim, Sungkyunkwan University, Suwon, South Korea
A hybrid structure of organic and inorganic building blocks enables us to design and tailor new materials with desired features and functions. Metal-oxo cluster molecules is one of the organic-inorganic hybrid materials. Metal-oxo cluster molecules having functional capping ligands offer remarkable promise in terms of thin film applications. Although there are a lot of metal-oxo cluster molecules reported so far, harnessing their potential is largely limited by lack of material processing strategy. We adopt a photothermally activated, cross-linked, and stable metal-oxo cluster molecular assembly based on hexanuclear zirconium-oxo cluster(Zr6-cluster), which can be a suitable for a new dielectric material in terms of electronic device applications since the zirconium-oxo core enhances the dielectric functionality and together the organic ligand (methacrylate) imparts a polymerizable functionality. In this study, we demonstrate that the photothermally activated zirconium-oxo cluster thin film can be successfully applied to a gate dielectric material for thin-film field-effect transistors with different active layers. Furthermore, the controlled crosslinking of Zr6-cluster enabled tuning of metal filament formation for memristor application.
P33 Production of Free-standing, Thin and Lead-free Barium Titanate Piezoceramics by Inkjet Printing
I. KETTERER1, C.-K. Yang1, E. Cimen1, M. Wapler2, T. Hanemann1, 3, j. SCHÖNFELDER1, 1Lab. for Materials Processing, Dept of Microsystems Engineering (IMTEK), University of Freiburg, Germany; 2Chair of Microsystems Engineering, Institute of Medical Engineering, Otto-von-Guericke University Magdeburg, Germany; 3Institute for Applied Materials - Materials Sciences and Engineering (IAM-WK), Karlsruhe Institute of Technology, Germany
With regard to the protection of human health and the environment, the search for lead-free alternatives to PZT continues to be a current research topic. Due to the tetragonally distorted perovskite structure below the Curie temperature of 120 °C, barium titanate (BaTiO3) has ferroelectric and piezoelectric properties and is a promising candidate as a substitute for PZT. This work deals with the production of extremely thin BaTiO3 ceramics for application in actuators. In detail, the aim is to develop multistable, programmable micro actuators using combined piezo and thermal actuation and lead-free piezoceramics. Here, the challenging processing of thin, planar and crack-free BaTiO3 ceramics in the size 15 x 20 mm2 with a layer thickness in the range of 100 – 120 µm without an underlying substrate is described. The barium titanate green bodies are produced via inkjet printing. This additive manufacturing technique brings the advantage of sustainability through material savings. The specially developed ink contains approx. 25 vol-% BaTiO3 dispersed in an organic solvent. The use of graphite substrates, which are ashed at 700 °C after the printing process, results in free-standing ceramics. These are finally sintered at 1100 °C.
P34 Versatile Solution-processed Reductive Interface Layers for Flexible Electronic Devices
KANG-JUN BAEG, Pukyong National University, Busan, South Korea
Efficient charge injection/extraction from/to contact electrodes is essential to realize organic electronic and optoelectronic devices with optimum characteristics for many applications. Herein, we studied a versatile reductive interlayer based on sodium borohydride to control the contact properties of the staggered organic field-effect transistors (OFETs) either by doping and/or by regulating the contribution of charge carriers. The versatile functionalities of the NaBH4 layer are mainly determined by the alignment of frontier molecular orbitals of donor−acceptor (D−A) type copolymer semiconductors and the work function of the contact electrode. After incorporating the NaBH4 layer, the work function of the bottom-contact gold electrode can be decreased significantly by 1.0 eV, which makes it favorable to efficient electron injection. An Ohmic contact is achieved by the spontaneous injection of electrons to the n-type organic semiconductors with high electron affinity while converting the OFET operation mode to n-type characteristics by blocking the counter-charge carriers for the other types of ambipolar and p-type
semiconductors. The solution-processed reducing agent can be a valuable approach to develop high-performance printed and flexible electronic devices.
P35 Electric Field Engineering of Switching Mechanisms in CB-RAM Devices
TAEWOOK Kim, T. Vogel, E. Piros, N. Kaiser, P. Schreyer, A. Arzumanov, S. Petzold, L. Alff, Advanced Thin Film Technology Division, Technische Universität Darmstadt, Darmstadt, Germany; D. Nasiou, R. Winkler, A. Zintler, L. Molina-Luna, Advanced Electron Microscopy Division, Materials, Technische Universität Darmstadt, Darmstadt, Germany
We have investigated the resistive switching properties and electrical conduction mechanism changes in Cu/HfO2/Pt ECM device with varying HfO2 oxide layer thickness. We found that the conducting filament is rupturing with different trends depending on the thickness of the HfO2 layer. In devices with thicker oxide layers, the conducting bridge is abruptly ruptured and requires a high set voltage, while in devices with thinner oxide layers, the conducting bridge gradually ruptures and requires only a low set voltage. We propose a Thermally Assisted Electrochemical Mechanism (TA-ECM) to describe the resistive switching behavior, which suggests that thermal effects are involved in the rupture of the Cu conducting bridge. In addition to the resistive switching behavior, we investigated the conduction mechanisms in the Cu/HfO2/Pt device. In conclusion, this study provides valuable insights into the resistive switching and electrical conduction mechanisms of Cu/HfO2/Pt devices with varying oxide layer thicknesses. The findings highlight the critical role played by the HfO2 layer thickness in the resistive switching behavior and conduction mechanism. The proposed TA-ECM model and conduction mechanism model enhance our understanding of the underlying physics in these devices.
P36 A Possible bio-ReRAM using Aloe Vera for Green Computing
S. Vallabhapurapu, School of Computing, University of South Africa, Florida Park, South Africa; Z. Wiseman Dlamini, Maths, Science and Technology Education, Central University of Technology, Bloemfontein, South Africa
Our study focuses on the investigation of the resistive switching property exhibited by aloe vera when placed between two electrodes. The novelty of our investigation resides in the utilization of a silver and aluminium electrode combination, thereby distinguishing our device from those previously reported in the scientific literature. The device under investigation exhibited switching at a remarkably low voltage of 0.1 V . Moreover, the phenomenon of multilevel switching was exclusively observed under negative voltage bias. The limitation of this device is attributed to the progressive development of hysteresis, resulting in the loss of the switching. The analysis of the conduction mechanism revealed that the formation of a conduction filament occurred as a result of the degradation induced by voltage in the active layer of aloe vera. This phenomenon ultimately resulted in resistive switching. In general, the resistive switching memory utilizing aloe vera exhibits a notable reliance on the electrodes. Consequently, meticulous evaluation of the electrode pairing is imperative for the purpose of maximizing the performance of this particular device.
P37 In Situ Thermal Measurement and Modeling of the Operation of Ovonic Threshold Switch
J.H. Park, M.J. Jung, H. Kim, S.Y. Lee, J.H. Jang, G.H. Kim, M.K. Yang, Byung Joon Choi, Seoul National University of Science and Technology, Seoul, South Korea
To address the sneak path current issue of high-density crossbar array, selector based on ovonic threshold switch (OTS) have been studied. Although OTS shows superior performance as the selector, these chalcogenide-based devices can be degraded due to Joule heating generated during operation. To understand such a degradation process from the perspective of heat, we conducted failure analysis with thermoreflectance (TR) imaging microscopy combined with electrical measurement. For this analysis, GeTe5 based OTS which show superior selector characteristics was fabricated on a Pt bottom electrode. A TiN metal layer was deposited on a chalcogenide thin film as a top electrode. As a result of in situ TR imaging analysis, the temperature during operation and localized volatile resistive switching characteristics were observed, which has not been well characterized before. Transmission electron microscopy analysis was conducted to see how Joule heating affected the change of microstructure during operation. In addition, time-domain thermoreflectance (TDTR) analysis was also conducted by using Transometer™ (TMX Scientific Inc., US). With Multiphysics simulation, we try to understand the Joule heating effect and furthermore its impact on failure of the OTS eventually.
P38 Study on the Strain Compensated 4.8 Micrometer InGaAs/InAlAs Quantum Cascade Lasers
W.J. Lee, J.W. Seo, J.H. Kang, Il Ki Han, Nanophotonics Research Center, KIST, South Korea; S. Kim, J. Kim, Department of Information Display, Kyung Hee University, South Korea; J.C. Shin, Div. Electronics and Electrical Engineering, Dongguk University, South Korea; T.G. Kim, School of Electrical Engineering, Korea University, South Korea
Strain-compensated InGaAs/InAlAs/InP material structures for quantum cascade lasers (QCLs) were grown by molecular beam epitaxy (MBE). The structure was simulated through a strain-modified effective two-band model [1]. From the high resolution X-ray diffraction (HRXRD) measurement, the composition and thickness of each InGaAs and InAlAs layers composing active and injector regions of QCL were investigated. The QCLs were fabricated by normal fabrication process and exhibited a lasing wavelength of ~4.8 micrometer. In particular, the interface between InGaAs and InAlAs inside the QCL structure was examined by Atomic Probe Tomography (APT). In this study, we will demonstrate the effect of the interface between InGaAs and InAlAs on device performance. [1] Kim SJ and Kim JH. Strain-modified effective two- band model for calculating the conduction band structure of strain-compensated quantum cascade lasers: effect of strain and remote band on the electron effective mass and nonparabolicity parameter.
Optics Express. 2021; 29:40957-40980.