Article
Materials Science, Multidisciplinary
Shota Suzuki, Moeko Matsubara, Hideaki Minamiyama, Marwan Dhamrin, Yasufumi Fujiwara, Yukiharu Uraoka
Summary: We conducted two-dimensional X-ray diffraction measurements during the formation of a silicon-germanium (SiGe) layer by a simple method of aluminum-germanium (Al-Ge) paste screen-printing and annealing. The study found that aluminum (Al) and germanium (Ge) in the Al-Ge paste enter the liquid phase at temperatures around 540°C and 430°C respectively. The SiGe layer grows epitaxially in the same direction as the silicon (Si) substrate by utilizing the liquid phase formed during the cooling process.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Physics, Applied
Yanxu Wang, Wu Gong, Takuro Kawasaki, Stefanus Harjo, Kun Zhang, Zhidong Zhang, Bing Li
Summary: In this study, the deformation behavior of the plastic inorganic semiconductor Ag2S was investigated using in situ neutron diffraction at different temperatures. The results showed that at room temperature, the distribution of lattice strain among different crystallographic plane families may be responsible for the significant work-hardening behavior in bulk Ag2S. At 453 K, Ag2S undergoes a phase transformation from monoclinic to body-centered cubic phase, with a stress plateau and subsequent rehardening. The deformation mode of bulk Ag2S at the initial stage is likely due to the migration of silver ions, and as strain increases, it resembles the behavior at room temperature, leading to rehardening.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
Hang Li, Weibo Hua, Bjoern Schwarz, Martin Etter, Stefan Mangold, Georgian Melinte, Nicola Pietro Maria Casati, Helmut Ehrenberg, Sylvio Indris
Summary: In this study, the structural and electronic changes of LiNiO2 at different temperatures were investigated through thermal treatments. Besides the decomposition process, a series of transformations were discovered under mild conditions, including the reaction with CO2 and the cation off-stoichiometry.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Rahmandhika Firdauzha Hary Hernandha, Bharath Umesh, Purna Chandra Rath, Le Thi Thu Trang, Ju-Chao Wei, Yu-Chun Chuang, Ju Li, Jeng-Kuei Chang
Summary: The lithiation/delithiation properties of alpha-Si3N4 and beta-Si3N4 are compared and the carbon coating effects are examined. Then, beta-Si3N4 at various fractions is used as the secondary phase in a Si anode to modify the electrode properties. The incorporated beta-Si3N4 decreases the crystal size of Si and introduces a new N-Si-O species at the beta-Si3N4/Si interface.
Review
Chemistry, Physical
Wenzao Li, Diana M. Lutz, Lei Wang, Kenneth J. Takeuchi, Amy C. Marschilok, Esther S. Takeuchi
Summary: To overcome the limitations of static and destructive characterizations of Li-ion battery materials and components, a comprehensive investigation over various length and time scales is essential. Emerging in situ and operando characterization methodologies focusing on multiple size domains are a powerful approach to resolve current challenges and navigate future directions. The necessity and opportunity for in situ and operando characterization of electrochemical energy storage materials and systems are discussed, along with suggestions for future directions to tackle currently intractable issues on Li-ion battery application, failure, and emerging design concepts.
Article
Chemistry, Physical
Sizhan Liu, Patrick J. West, Hui Zhong, Jianming Bai, Eli Stavitski, Denis Leshchev, Amy C. Marschilok, Esther S. Takeuchi, David C. Bock, Kenneth J. Takeuchi
Summary: In intercalation materials, the kinetics and uniformity of mass transport across the nanocrystalline domains are crucial for the structural reversibility and transport capability at the macroscopic level. This study investigates the origins of compositional and orientational-dependent phase separations in LiNi0.8Mn0.1Co0.1O2 during electrochemical cycling, providing insights into crystallographic orientation-dependent phase inhomogeneity under fast charge and extended cycling.
CHEMISTRY OF MATERIALS
(2023)
Article
Geochemistry & Geophysics
Vasilije V. Dobrosavljevic, Dongzhou Zhang, Wolfgang Sturhahn, Jiyong Zhao, Thomas S. Toellner, Stella Chariton, Vitali B. Prakapenka, Olivia S. Pardo, Jennifer M. Jackson
Summary: This study develops a multi-technique approach to measure the high-pressure melting and solid phase relations of iron alloys and investigates the effect of silicon on melting temperatures and phase diagram. The results show that the addition of 10 mol% silicon reduces melting temperatures and flattens the phase boundary at low pressures.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Endale Abebe Gudeta
Summary: This study introduces a modified version of the Enzo-Parrish method to determine a straight background level with a nonzero gradient. The proposed method uses a scattering vector to determine the background and is validated on the XRD peak of a polymer sample.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Chemistry, Physical
Shigeharu Takagi, Keiji Shimoda, Jun Haruyama, Hisao Kiuchi, Ken-ichi Okazaki, Toshiharu Fukunaga, Zempachi Ogumi, Takeshi Abe
Summary: In this study, operando structural analyses of graphite electrode in lithium-ion batteries were performed using neutron diffraction and synchrotron radiation X-ray diffraction. The results provide insights into the phase evolution and structural transition of lithium-intercalated graphite. The study reveals that the in-plane structure of graphite transitions from LiC6-type to LiC9-type during lithium de-intercalation, and the LiC9-type arrangement is retained in Li-poor phases. This research is significant for understanding the structural changes in lithium-ion battery materials.
Article
Materials Science, Multidisciplinary
Rachel E. Lim, Darren C. Pagan, Donald E. Boyce, Joel Bernier, Paul A. Shade, Anthony D. Rollett
Summary: This study utilized high energy x-ray diffraction microscopy to investigate the anisotropic coefficients of thermal expansion for Ti-7Al alloy. It was found that grain-level internal stresses are affected by crystal structure changes and the dissolution of precipitates.
MATERIALS CHARACTERIZATION
(2021)
Article
Chemistry, Physical
Karolina Kutynia, Piotr Gebara
Summary: This study investigated the influence of partial substitution of Mn by Zr in MnCoGe alloys. It was found that Zr addition resulted in changes in lattice constants, phase content, structural transformation, and a decrease in Curie temperature. Samples doped with Zr showed a significant increase in magnetic entropy change.
Article
Nanoscience & Nanotechnology
Ryoji Katsube, Litian Luo, Keita Nakano, Taka Narumi, Hideyuki Yasuda
Summary: The solidification sequence of the CrMnFeCoCu alloy, a multicomponent and multiphase alloy derived from the CrMnFeCoNi alloy, was investigated. It was found that the microstructure of this alloy formed through a process of liquid-liquid phase separation and subsequent solid-phase transformation, rather than the conventional multiphase solidification manner. The understanding of these processes can contribute to the control of microstructure in multicomponent and multiphase alloys.
SCRIPTA MATERIALIA
(2023)
Article
Electrochemistry
Zhaoshun Wang, Yong Wang, Dechao Meng, Qinfeng Zheng, Yixiao Zhang, Feipeng Cai, Di Zhu, Jiabing Liu, Yushi He, Liwei Chen, Zi-Feng Ma, Linsen Li
Summary: The O2-type layered oxide cathode materials have gained significant research attention due to their high specific capacity and unique lattice structure. In this study, we investigated the structural, chemical, and morphological changes during ion-exchange processes for the preparation of these materials using LiBr/hexanol solution and LiNO3/LiCl molten salts. The solution method was found to be preferable for preparing high-capacity O2-type cathode materials, despite slower structural reorganization compared to the molten-salt method. It was discovered that the as-made O2-type cathode materials were actually Li-deficient at their pristine states but could accept more Li ions during the first charge/discharge cycle.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Shuo Feng, Rajesh Kumar Singh, Yucheng Fu, Zhuo Li, Yulong Wang, Jie Bao, Zhijie Xu, Guosheng Li, Cassidy Anderson, Lili Shi, Yuehe Lin, Peter G. Khalifah, Wei Wang, Jun Liu, Jie Xiao, Dongping Lu
Summary: In this study, a simple strategy was demonstrated for constructing low-tortuosity through-pores in both vertical and planar directions of electrodes by casting large particles into single-particle-layer electrodes. Through multi-scale characterizations and simulations, correlations between material/electrode structures, electrolyte permeability, polysulfide migration, and sulfur reactions were elucidated. The high-loading and dense sulfur cathode fabricated by this method delivers a high specific capacity at a very low electrolyte/sulfur ratio.
ENERGY & ENVIRONMENTAL SCIENCE
(2022)
Article
Chemistry, Physical
Albert Carrillo, Jason Daza, Joan Saurina, Lluisa Escoda, Joan-Josep Sunol
Summary: Two nanocrystalline ferromagnetic alloys of the Fe-Co-Nb-B system were produced by mechanical alloying, and their microstructure, thermal behavior, and magnetic response were studied. The increase in Co content leads to a decrease in dislocation density and an increase in activation energy of the crystallization process, while having no significant impact on the saturation magnetization. Additionally, lower Co content in the alloy results in lower coercivity.
Article
Chemistry, Multidisciplinary
Kewei Sun, Kazuma Sugawara, Andrey Lyalin, Yusuke Ishigaki, Kohei Uosaki, Tetsuya Taketsugu, Takanori Suzuki, Shigeki Kawai
Summary: The researchers successfully transformed C-N bonds on a metal surface and discovered a novel nitrogen heterocyclic segregation reaction. Density functional theory calculations showed that the ring-forming and -opening of N-heterocycles are strongly influenced by the hydrogen-substrate interaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Ruby A. Sims, Hidenori Noguchi, Sarah L. Harmer, Jamie S. Quinton, Kohei Uosaki
Summary: The research revealed the order of propyl chains during the adsorption of PTMS and PDMMS, as well as the impact of molecular packing density on film defects. Additionally, the formation of a physisorbed bilayer during the self-assembly process of PTMS was discovered for the first time, which is proposed to facilitate further condensation of the covalently bound film.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Chemistry, Physical
Shoichi Matsuda, Shoji Yamaguchi, Eiki Yasukawa, Hitoshi Asahina, Hirofumi Kakuta, Haruhiko Otani, Shin Kimura, Takashi Kameda, Yoshiki Takayanagi, Akihiko Tajika, Yoshimi Kubo, Kohei Uosaki
Summary: The research highlights the importance of electrolyte distribution in porous carbon electrodes for the performance of LOBs, emphasizing the significance of electrolyte filling techniques in achieving high-energy-density LOBs.
ACS APPLIED ENERGY MATERIALS
(2021)
Review
Chemistry, Physical
Ken Sakaushi, Kohei Uosaki
Summary: This review summarizes the latest experimental/theoretical collaborative research focusing on understanding the fundamental aspects of electron/proton transfer in surface electrochemical reactions from the perspective of materials. It explores the optimal choice of Pt- or metal-free electrocatalysts based on previously rejected material categories.
CURRENT OPINION IN ELECTROCHEMISTRY
(2021)
Review
Chemistry, Multidisciplinary
Shoichi Matsuda, Manai Ono, Shoji Yamaguchi, Kohei Uosaki
Summary: Theoretical energy density of conventional LiBs is insufficient for advanced energy storage, leading to the exploration of lithium-air batteries (LABs) with higher theoretical energy density. However, actual energy density of LABs is often lower due to excess electrolyte. This review article estimates practical energy density of LABs and identifies critical factors for improving their energy density, proposing criteria for evaluating LABs in industry.
MATERIALS HORIZONS
(2022)
Article
Chemistry, Physical
Ben Wang, Mikio Ito, Min Gao, Hidenori Noguchi, Kohei Uosaki, Tetsuya Taketsugu
Summary: The effect of metal substrates on the chemical bonding nature at molecule-metal interfaces was investigated for aryl isocyanide molecules with different para-substituents. Both experimental and theoretical results confirm that the metal substrate increases the NC stretching frequency, with a larger effect observed on the Au(111) surface compared to the Ag(111) surface. The analysis further reveals that the sigma donation from the molecule to the substrate is more pronounced than the pi back-donation, and the effect is stronger for the Au substrate.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Shoichi Matsuda, Manai Ono, Hitoshi Asahina, Shin Kimura, Emiko Mizuki, Eiki Yasukawa, Shoji Yamaguchi, Yoshimi Kubo, Kohei Uosaki
Summary: In this study, it is revealed that the reaction efficiency of the negative lithium electrode largely decreases due to chemical crossover from the positive oxygen electrode side. By fabricating an ultra-lightweight flexible ceramic-based solid-state separator, the lithium electrode is effectively protected against chemical crossover without diminishing the energy density of LOBs. This study sheds light on the direction for the practical implementation of LOBs with high energy densities and long cycle lives.
ADVANCED ENERGY MATERIALS
(2023)
Article
Chemistry, Physical
Hung Cuong Dinh, Ganesan Elumalai, Hidenori Noguchi, Andrey Lyalin, Tetsuya Taketsugu, Kohei Uosaki
Summary: In this study, the electrocatalytic activities of gold (Au) electrodes for the oxygen reduction reaction (ORR) were enhanced by modifying the Au surface with size-selected hexagonal boron nitride nanosheets (BNNS). The smaller the size of the BNNS, the lower the overpotential for ORR and the higher the ORR activity. The smallest BNNS size range (0.1-0.22 μm) reduced the overpotential by as much as 330 mV compared to a bare Au electrode, and it exhibited an ORR activity only 80 mV higher than that of a platinum (Pt) electrode.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Shoichi Matsuda, Shin Kimura, Kohei Uosaki
Summary: In this study, ex situ X-ray computerized tomography (XCT), in situ internal pressure monitoring, and in situ confocal microscopy were employed to study the physical states of the electrodes and the electrolyte in high energy density lithium-oxygen batteries (LOBs). The analysis revealed large irreversible volume changes in both the positive and negative electrodes, as well as electrolyte displacement from the pores of the positive electrode during the discharge process. These new insights into the physical behavior of LOBs during cycling conditions provide effective means for designing LOBs with high energy density and long cycle life.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Yanan Gao, Hidenori Noguchi, Kohei Uosaki
Summary: We studied the molecules produced during the discharge/charge of a TEGDME-based lithium-oxygen battery using a new online system. 37 peaks were detected, with 27 being assigned to specific molecules. Impurities from TEGDME, as well as molecules generated during charge, were observed, indicating direct electrochemical oxidation.
ACS ENERGY LETTERS
(2023)
Article
Chemistry, Physical
Yoshitaka Tateyama, Akiko Kagatsume, Masaru Yao, Shoichi Matsuda, Kohei Uosaki
Summary: Organic cathode active materials (CAM) with lightweight frameworks and higher energy density are potential candidates for next-generation batteries. In this study, the characteristics of two organic crystals (naphthazarin lithium salt dimer and phenazinetetrone) were analyzed by density functional theory (DFT) calculations. The results showed that phenazinetetrone exhibits better cathode performance.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Mehdi Estili, Shoichi Matsuda, Lulu Jia, Nobuyuki Sakai, Renzhi Ma, Tohru S. Suzuki, Kohei Uosaki
Summary: The effectiveness of multiwalled carbon nanotubes (MWCNTs) in enhancing the suitability of MXenes for energy-related applications is explored. The control over the structure of MXene-based macrostructures by individually dispersed MWCNTs is investigated. The results show that the composition and surface structure of MXene films are significantly altered by the presence of MWCNTs. The stacking order of MXenes is preserved up to 30 wt% MWCNTs, but disrupted at 40 wt%. The membranes with MWCNTs exhibit improved Li-ion transport mechanisms and properties. A high rating of 8 is given for the importance of this research.
Article
Chemistry, Multidisciplinary
Yanan Gao, Hidenori Noguchi, Kohei Uosaki
Summary: The degradation products of lithium oxygen batteries using TEGDME electrolyte solution were monitored in real time during discharge/charge cycles. A total of 37 peaks were detected, with 27 of them being identified as specific molecules. The degradation compounds exhibited complex generation and decomposition processes during the cycles. Most of the molecules were generated during charge due to the degradation of TEGDME by active oxygen species and/or electrochemical oxidation, and they were subsequently decomposed during discharge by active oxygen species.
Article
Chemistry, Multidisciplinary
Kewei Sun, Kazuma Sugawara, Andrey Lyalin, Yusuke Ishigaki, Kohei Uosaki, Oscar Custance, Tetsuya Taketsugu, Takanori Suzuki, Shigeki Kawai
Summary: In this study, complex organometallic oligomers were systematically synthesized on Cu(111) through sequential ring opening and bonding of phenanthroline derivatives by multiple Cu atoms. Characterization using scanning tunneling microscopy and density functional theory calculations revealed the role of Cu adatoms in the chiral oligomers. Furthermore, the strength of the bonds against sliding friction was found to be sufficient.
Article
Chemistry, Physical
Shoichi Matsuda, Eiki Yasukawa, Shin Kimura, Shoji Yamaguchi, Kohei Uosaki
Summary: This study evaluates the performance of LOBs under different experimental conditions, revealing unique degradation phenomena under lean-electrolyte and high areal capacity conditions. The importance of considering the electrolyte amount against areal capacity ratio and gas-diffusion layer materials when evaluating LOBs performance is emphasized.
FARADAY DISCUSSIONS
(2023)
